* GB786174 (A)

Description: GB786174 (A) ? 1957-11-13

Improvements in or relating to chemical nickel plating process

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION Inventor: PAUL TALMEY Date of Application and filing Complete Specification: Feb 28, 1955. No 5857/55. Complete Specification Published: Nov 13, 1957. Index at acceptance:-Class 82 ( 2), F(WBIB: 2 J; 2 Z 6), F 4 (A; E; F; G; J: K; W; X). international Classification;-C 23 c. COMPLETE SPECIFICATION Improvements in or relating to Chemical Nickel Plating Process We, GENERAL AMERICAN TRANSPORTATION COR Po RAT Io N, a corporation organised under the laws of the State of New York, United States of America, of 135 South La Salle Street, City of Chicago, State of Illinois, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to improved processes of chemical nickel plating of catalytic materials employing baths of the nickel cation-hypophosphite anion, type, and more particularly to continuous processes of chemical nickel plating. The chemical nickel plating of a catalytic material employing an

aqueous bath of the nickel cation-hypophosphite anion type is based upon the catalytic reduction of nickel cations to metallic nickel and the corresponding oxidation of hypophosphite anions to phosphite anions with the evolution of hydrogen gas at the catalytic surface The reactions take place when the body of catalytic material is immersed in the plating bath, and the exterior surface of the body of catalytic material is coated with nickel The following elements are catalytic for the oxidation of hypophosphite anions and thus may be directly nickel plated: iron, cobalt, nickel, ruthenium, rhodiumi palladium, osmium, iridium and platinum The following elements are examples of materials which may be nickel plated by virtue of the initial displacement deposition of nickel thereon, either directly or through a galvanic effect: copper, silver, gold, beryllium, germanium, aluminium, carbon, vanadium, molybdenum, tungsten, chromium, seleniuml, titanium and uranium The following elements are examples of non-catalytic materials which may not be nickel plated,: bismuth, cachniumi, tin, lead and zinc The activity of the catalytic materials varies considerably; and the following elements are particularly good catalysts, in the chemical nickel plating bath: iron, cobalt, nickel and pallat Price 3 s 6 d l diumi The chemical nickel plating process is autocatalytic since both the original surface of the body being plated and the nickel metal 50 that is deposited on the surface thereof are catalytic. In the continuous nickel plating system disclosed in copending application No 19063/ 53 (Serial No' 785,693), periodic or' con 55 tinuous regeneration of the plating bath is effected by the corresponding additions thereto of appropriate ingredients; for the purpose of maintaining substantially constant the coinposition of the plating bath The regeneration 60 of the plating solution in the reservoir consistsi essentially of adding thereto appropriate amounts of soluble nickel-containing and hypophosphite-containing reagents, as well as an alkali for p H control 65 In the continuous plating system, plating baths such as disclosed in our' copending application No 36334/53 (Serial No 785,696), areexpressly recommended, since they exhibit an exceefdingly fast plating rate, and have an 70 exceedingly long life because they acommodate the build-up of phosphite anions therein to' a concentration above 1 0 mole/ litre, without the precipitation of nickel phosphite and mixed basic salts 75 Also for the purpose of increasing the stability of such a plating bath, it is highly advantageous to add thereto a stabilizing additive, as disclosed in our eopending applications No 31365/53 and 22974/56 (Serial 80 Nos 785,694 and 786,175). In carrying out the continuous nickel plating process described in coplending application 19063/53 (Serial No 785,693) the regeneration

of the relatively cool portion of 85 the aqueous plating solution in the reservoir may be ekced either periodically or continuously during the time interval that the body of catalytic material is being plated in. the hot portion of the plating solution in the 90 plating chamber, as previously noted, whereby the additions of the nickel salt (such as nickel chloride, nickel sulphate and nickel acetate) bring about the introduction of the corres- 786,174 2 786,174 ponding foreign anions into the aqueous solution, with the consequent build-up thereof through the successive cycles of regeneration to a point where the concentration of the foreign anions in the aqueous solution is excessive More particularly, the concentration of the foreign anions in the aqueous plating solution is excessive in the sense that the plating rate of the bath in the plating chamber is s Iowed-down considerably; and mloreover, these foreign anions, in excessive concentration, serve as crystal nuclei for the precipitation of nickel salts, resulting in plating bath instability. Specifically, by way of illustration, it has been discovered that the plating rate of a plating bath such as mentioned in copending application No 36334/53 (Serial No 785,696) decreases linearly with the concentration of Nael therein resulting from the employment of nickel chloride in the regeneration thereof. More particularly, the rate of decrease of the plating rate of the plating bath with the increase in the concentration of Na Gl is: ( O 00053 grms/min,/cni P)/(moles Na Cl/litre) In ether words, if the sodium chloride concentration, is raised froml zero to 6 0 males/ litre in the plating bath, the plating rate becomes less than half of its original value. Moreover, another phenomenon has been. discovered in, this connection that is sometimes undesirable, i e, the hardness of the nickel deposit upon the body of catalytic material increases with the chloride concentration in the plating bath. Accordingly, it is a general object of the present invention to provide an improved process of chemical nickel plating of bodies formed of catalytic material, employing a continuous chemical nickel plating operation involving plating bath regeneration, wherein the build-up of foreign anions as a consequence of the introduction of the soluble nickel salt into the plating bath is not excessive as the regeneration of the plating bath proceds. Another object of the invention is to provide an improved process of chemical nickel plating of the character noted, wherein the plating bath regeneration is at least partially effected by the utilization of nickel hypephosphite, whereby there is no foreign anion, of this

soluble nickel salt introduced into the plating bath. A further object of the invention is to provide an improved nickel plating process of the character described, wherein the plating bath regeneration proceeds without the build-up therein of foreign anions, such as, the chloride, the sulphate and the acetate. These and other objects and advantages of the invention pertain, to the particular arrangement of the steps of the process, as will be understood from the foregoing and following description 65 The present invention provides a process of chemically plating with nickel a solid body of catalytic material, which comprises contacting said body throughout a time interval with an aqueous bath containing nickel ions and hypo 70 phosphite ions, and regenerating said bath during said time interval by adding thereto appropriate amounts of a soluble alkali, nickel hypophosphite and another soluble hypophosphite comprising hypophosphorous acid and/ 75 or an alkaline hypophosphite (the term "alkaline hypophosphite" means herein a hypophosphite which is an alkali metal or an alkaline earth metal hypophosphite), thereby to minimize the introduction of extraneous ions into 80 said bath and the consequent build-up of undesirable salts therein, incident to the regeneration thereof. In accordance with the process of the present invention, the article or body to be 85 nickel plated, is prepared by mechanically cleaning, degreasing and light pickling substantially in accordance with known standard practices in the art For example, in the nickel plating of a steel object, it is customary mech 90 anically to cleans the rust and mill scale from the object, to degrease the object, and then lightly to pickle the object in a suitable acid, such as hydrochloric acid The article is then immersed in the plating bath provided in the 95 plating chamber of the continuous system described in copending application, No 19063/ 53 (Serial No 785,693); whereupon almost immediately hydrogen bubbles are formed on the catalytic surface of the steel object and 100 escape in a steady stream from the plating bath, while the surface of the steel object is slowly coated with metallic nickel (containing some phosphorus) The reactions are continued until the required thickness of the 105 nickel coating has been deposited upon the surface of the steel object; whereupon the steel object is removed from the plating bath in the plating chamber of the continuous system, and is rinsed off with water so that 110 it is ready for use. In the formation of the plating solution in accordance with the present invention, the soluble nickel salt that is employed is selected from the group consisting of nickel chloride, 115 nickel sulphate, nickel acetate and nickel hypophosphite, the other hypophosphite that is employed is selected from the group, consisting

of hypophosphorous acid, sodium hypophosphite, potassium hypophosphite and calcium 120 hypophosphite, the organic additives and appropriate stabilizing cations are then introduced into the aqueous plating bath, and the p-H thereof is appronriately adjusted employing Na OH and Na CI Thereafter and during 125 the time interval that the body is being nickel plated the plating bath is regenerated, as pre786,174 viously described, employing nickel hypophosphite, another hypophosphite (ordinarily an, alkaline hypophosphite, such as sodium hypophosphite) and preferably a weak alkali, such as, sodium bicarbonate or a dilute aqueous solution of caustic soda, for pl H control The reagents may be added continuously or periodically during said time interval, and preferably, to' a cool portion of the solution, such as that in the reservoir of the system in copending application 19063/53 In, one embodimnent of the present invention the absolute concentration of hypophosphite in the bath expressed in moles/litre is within the range 0 15 to 1 20 The plating bath is generally maintained at a p H of 4 5 to) 9 5, preferably 4.5 to 7 0. The process of plating may be further facilitated by the addition to the plating solution of an agent in an amount at least sufficient to' complex 100 % of the nickel ions therein and comprising a saturated aliphatic hydroxy-carboxylic acid and/or a salt thereof and an additive exalting the normal plating rate theof and comprising a simple short chain saturated aliphatic dicarboxylic acid and/or al salt thereof or an aliphatic amino carboxaylic acid and/or salt thereof It may be carried out by circulating the plating solution from a reservoir to' a plating chamber and then back to said reservoir, heating said solution to a relatively high temperature slightly below the boiling point thereof, preferably to 2100 F, after withdrawal thereof from said reservoir and before introduction thereof into, said plating chamber, cooling said solution to a relatively low temperature well below the boiling point thereof, preferably to F, after withdrawal thereof from said plating chamber and before return thereof to said reservoir, immersing said body in the hot portion of said solution in said plating chamber toi effect nickel plating: on the surface of said body, withdrawing said body from said hot portion of said solution in said plating chamber after a time interval corresponding to the thickness of the nickel plating on the surface of said body that is desired, and regenerating said solution during said time interval to) compensate for the ingredients of said solution that are exhausted during said time interval in said hot portion of said solution in said plating chamber, said regeneration of said solution consisting essentially of adding to the cool portion of said solution in said reservoir appropriate amounts of nickel hypophosphite and another soluble hypophosphite and a soluble alkali, said other

hypophosphite being selected from the group consisting of hypophosphorous acid and alkaline hypophosphites, thereby toa minimize the introduction of extraneous ions into' said bath and the consequent build-up' of undesirable salts; therein incident to the regeneration thereof. In the regeneration of the plating solution, the depletion of the nickel cations is compensated for by the addition of the nickel hypophosphite, and the depletion of the hypophosphite is compensated for by the additions of the nickel hypiophosphite and the other hypophosphite, it being necessary to add both the nickel hypophosphite and the other hypophosphite to the plating solution to' maintain the desired ratio, between the nickel cations and the hypophosphite anions in the range O 25 to 1 60 The addition of the alkali to' the plating solution in the regeneration thereof is necessary since the p H of the plating solution is automatically reduced as the reactions therein proceed, whereby the addition of the alkali mentioned maintains the p H of the plating solution in the range 4 5 to 9 5, preferably 4 5 to 7 0. In accordance with the present process, the initial concentration of sodium chloride prcsent in the aqueous plating solution, when nickel chloride is employed in the initial formation, thereof, is not excessive, and the concentration of sodium chloride therein is not built-up as a consequence of the regeneration thereof by virtue of the utilization of nickel hypophosphite, thereby avoiding the build-up of the foreign chloride anion, as previously explained. In, order to' demonstrate the present process, a first plating test was performed in the continuous plating system described in copending application No 19063/53 (Serial No 785,693) in which there is a continuous flow of plating solution, employing previously cleaned cold rolled steel samples and a plating bath of the character described in copending application No' 36334/53 and having the particular composition indicated below: PLATING BATH NO 1 Nickel chloride 0 0675 moles per Litre Sodium hypophosphite 0 225, , Sodium succinate 0 06,, ,,, Malic acid 0 135,,. Pb++ as stabilizing ion 3 0 ppm Ratio: Ni++/hypor 0 3 Initial p 1 H adjusted with Na OH 5 57 In this first continuous plating test, it was assumed that the hy pophosphite utilization was 0.3 for purposes of plating bath regeneration, and in this connection hypophosphite utilization may be defined as the ratio between the number of moles of nickel deposited in the plating operation and the number of moles of hypophosphite consumed in the plating operation h I other words, in this continuous system in order to plate 3 moles of nickel upon the steel bodies 10 moles of hypopihosphite are oxidized to' phosphite, which, of course, indicates

that in the regeneration of the plating bath, it is necessary to add thereto 786,174 somewhat in excess of three times as many moles of hypophosphite as moles of nickel. This first continuous plating test was conducted through 11 cycles, the temperature of the plating bath in the plating chamber being C, with plating bath regeneration at the conclusion of each cycle (employing nickel hypophosphite and sodium hypophosphite-to' supply the required nickel cations and hypophosphite anions and to maintain the desired ratio therebeeveen, and employing caustic soda to maintain the p H within the desired range). The results of this first continuous plating test were as follows: Cycle No. Initial p H Final p H Time of plating (min) Sample area cm 2 5.57 5 52 5 60 5 60 5 55 4.92 5 20 5 22 5 28 5 24 112 116 106 122 97 97 97 97 97 Wt gain, gms. 5.01 5 38 4 91 4.92 5 74 Rate Rx 10 Soln flow rate cc/min. Cycle No. Initial p H 4.62 4 78 4 86 5 08 4 85 51 49 50 57 47 5.52 11 5.52 5 50 5 52 5 51 5 51 Final p H Time of plating (min) 5.33 5 32 5 35 5 41 106 104 101 111 108 81.5 81 5 81.5 81 5 81 5 98 5 Wt gain, gms. Rate R x 104 Solu flow rate cc/min. 4.57 4 43 4 24 4 63 4 55 5 77 5.29 5 20 5 15 5 12 5 16 5 27 54 55 50 51 53 51 A second plating test was performezd in the continuous plating system described in copending application 19063/53 in which there is a continuous flow of plating solution employing previously cleaned cold rolled steel samples and a plating bath of the character described in copending application No 36334/ 54 (Serial No 785,696) and having the par 45 ticular comrposition indicated below: is Sample area cm 2 5.40 5 37 111 86,114 PLATING BATH NO 2 Nickel chloride 0 0675 moles/Litre Sodiumi hypophosphite 0 225,, Aminoacetic acid 0 0675,, Malic acid 0 2025,, Pb++ as stabilizing ion 3 0 ppm Ratio: Ni++/hypo 0 3 Initial pi H adjusted with Na OH 6 52 In this second continuous plating test, it was assumed that the hypophosphite utilization was 0 3 for purposes of plating bath reCycle No. generation, as previously explained This second continuous plating, test was conducted through 11 cycles, the temperature of the plating bath in the plating chamber being C, with plating bath regeneration at the conclusionl of each cycle (employing nickel hypophosphite and sodium hypophosphite to' supply the required nickel cations and hypophosphite anions and to maintain the desired ratio therebetween, and employing caustic soda to maintain the p H within the' desired range). The results of this second continuous plating test were as follows:

Initial p H Final p H Time of plating (min) Sample area, cm 2 6.52 5.51 6.51 6.53 6.51 6 49 5.87 5 82 5 95 5 95 106 118 97 97 97 97 97 Wt gain, gms. Rate R x 104 So In flow rate cc/min. Cycle No. 5.71 6 00 6 96 6 65 5 34 4.92 5 83 5 98 5 82 5 68 48 54 48 48 59 Initial p H Final p H Time of plating, (min) Sample area, cm 2 6.50 6 51 6.50 6 48 6 48 6 48 6.09 6 28 6 28 6 29 6 20 6 30 127 119 136 111 81.5 81 5 81 5 81 5 81 5 98 5 Wt gain, gms. Rate R x 104 6.01 5 72 6 02 6 18 5.81 5.90 5 91 6.37 6 60 5.62 5 80 6 04 Soln flow rate cc/min. 48 49 42 42 51 A third continuous plating test was performed in the continuous plating system de, scribed in copending application 19063/53 in which there is a continuous flow of plating solution, employing previously cleaned cold rolled steel samples and a plating bath of the 55 character described in copending application No 36334/53 (Serial No 785,696) and having the particular composition indicated below: 11 PLATING BATH NO 3 Nickel hypop'nosphite 0 0675 moles/Litre Sodiumhypophcsphite 0 09 Arninoacetic acid 0 0675,, Malic acid 0 135 Pb++ as stabilizing ion 3 0 ppm Ratio: Ni++/hypo O 3 Initial p H adjusted with Na OH 6 5 In this third continuous plating test, it was assumed that the hypophosphite utilization was 0 33 for purposes of plating bath regenCycle No. Initial p H Final p H Time of plating, (min) Sample area, cm 2 Wt gain, gms. Rate R x 104 So In flow rate cc/min. Loss of Nickel Ni++ moles/litre 6.51 5.68 4.67 4.88 0.0151 eration, as previously explained This third continuous plating test was conducted through 8 cycles, the temperature of the plating bath in the plating chamber being 100 C, with plating bath regeneration at the conclusion of each cycle (employing nickel hypophosphite and sodium hypophosphite to supply the required nickel cations and hypophosphite anions and to maintain the desired ratio therebetwen, and employing caustic soda to maintain the p H within the desired range). The results of this third continuous plating test were as follows: 6.61 5.82 102 5.26 5.33 0.0292 6.58 6.09 5.17 5.33 0.0444 6.60 6.00 103 5.29 5.29 0.0585 Cycle No 5 6 7 8 Initial p H 6 48 6 51 6 50 6 55 Final p H 6 01 6 06 6 12 6 22 Time of plating, (min) 101 106 120 107 Sample area, cm 2 97 97 97 98 7 Wt gain, gins 5 27 5 34 6 24 5 73 Rate Rx 104 5 39 5 20 5 36 5 42 Soun flow rate cc/min 57 54 47 53 Loss of Nickel Ni++ 0 0726 0 0868 0 1035 0 1187 moles/litre In the foregoing continuous plating tests, the nickel deposits upon the cold rolled steel samples were homogeneous, smooth and bright, the plating rates

indicated correspond to rates in excess of 1 5 mils ( O 0015 inch) per hour, and the plating baths were totally devoid. of turbidity or black precipitate Accordingly, these plating tests clearly demonstrate the highly satisfactory commnercial character of the present process. In the foregoing continuous plating tests, it will be observed that in the formation of plating baths Nos 1 and 2, the nickel salt employed was nickel chloride; whereas in the formation of plating bath No 3, the nickel salt employed was nickel hypophosphite On 786,174 786,174 the other hand, in the regeneration of the plating baths between cycles in each of the continuous plating tests, the nickel salt em; ployed was nickel hypophosphite Accordingly, it becomes substantially immaterial whether the plating bath is initially formed utilizing as the nickel salt, nickel chloride, nickel sulphate, nickel acetate or nickel hypephosphite, since the introduction of the foreign anions thereinto is not excessive, as long as the regeneration of the plating bath between cycles is carried out employing nickel hypophosphite. In the foregoing discussion and tests the plating rate may be defined: R = weight gain in the nickel plating in gram/cm 12/minu te of the plated surface of the test sample, or expressed simply: R = gmi/cm/n/min In, view of the foregoing, it is apparent that there has been provided an improved process of chemical nickel plating of catalytic bodies that is particularly well-suited to the production of commercial coatings, since the process is continuous', and the plating bath exhibits an exceedingly fast plating rate and has an exceedingly long life.

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* GB786175 (A)

Description: GB786175 (A) ? 1957-11-13

Improvements in or relating to chemical nickel plating bath and process

Description of GB786175 (A) Translate this text into Tooltip

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION 786,175 Date of Application and filing Complete Specification: Nov 12, 1953. No 229741 f 56. Application made in United States of America on June 3, 1953. \-r, /(Divided out of No 785,694) Complete Specification Published: Nov 13, 1957. Index at acceptance:-Class 82 ( 2), F( 1 81 B:2 U:2 Z 6), F 4 (A:E:FW::J:K:W:X). International Classification:-C 23 c. COMPLETE SPECIFICATION Improvements in or relating to Chemical Nickel Plating Bath and Process We, GENERAL AMERICAN TRANSPORTATION CORPORATION, a corporation organised under the laws of the State of New York, United States of America, of 135 South La Salle Street, Chicago, Illinois, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention relates to improved processes of chemical nickel plating of catalytic materials employing baths of the nickel cation-hypophosphite anion type containing stabilizing agents. The chemical nickel plating of a catalytic material employing an aqueous bath of the nickel cation-hypophosphite anion type is based upon the catalytic reduction of nickel cations to metallic nickel and the corresponding oxidation of hypophosphite anions to phosphite anions with the evolution of hydrogen gas at the catalytic surface The reactions take place when the body of catalytic material is immersed in the plating bath, and the exterior surface of the body of catalytic material is coated with nickel The following elements are catalytic for the oxidation of hypophosphite and thus may be directly nickel-plated, iron, cobalt, nickel, ruthenium rhodium, palladium,

osmium, iridium and platinum The following elements are examples of materials which may be nickel-plated by virtue of the initial displacement deposition of nickel thereon either directly or through a galvanic effect: copper, silver, gold, beryllium, germanium, aluminium, carbon, vanadium, molybdenum, tungsten, chromium, selenium, titanium and uranium The following elements are examples of non-catalytic materials which may not be nickel-plated: bismuth, cadmium, tin, lead and zinc The activity of the catalytic materials varies considerably; and the following elements are particularly good lPrice 3/61 catalysts in the chemical nickel plating bath: iron, cobalt, nickel and palladium The chemical nickel plating process is autocatalytic since both the original surface of the body being plated and the nickel metal that 50 is deposited on the surface thereof are both catalytic, and the reduction of the nickel cations to metallic nickel in the plating bath proceeds until all of the nickel cations have been reduced to metallic nickel, in the pre 55 sence of an excess of hypophosphite anions, or until all of the hypophosphite anions have been oxidized to phosphite anions, in the presence of an excess of nickel cations. Actually the reactions are slowed-down 60 rather rapidly as time proceeds because the anions, as contrasted with the cations, of the nickel salt that is dissolved in the plating bath combine with the hydrogen cations to form an acid, which, in turn, lowers the p H 65 of the bath, and the reducing power of the hypophosphite anions is decreased as the p H value of the bath decreases Moreover, there is a tendency for the early formation in the plating bath of a "black precipitate" that 70 results from a random chemical reduction of the nickel cations Of course, this formation of the black precipitate comprises a decomposition of the plating bath and is particularly objectionable in that it causes 75 the nickel deposit to be coarse, rough and frequently porous. For the dual purposes of increasing the stability of the plating bath (preventing the formation of the black precipitate men 80 tioned), and of increasing the normal plating rate of the bath, various baths of the present type have been suggested employing different additives or agents that serve either as buffers or as exaltants A chemical nickel 85 plating bath of the nickel cation-hypophosphite anion type has been proposed that contains as an additive a buffer in the form of a soluble salt of an organic acid, particularly sodium acetate A chemical nickel plating 90 ? e 25 p -:'I r 4NS I 786,175 bath of the nickel cation-hypophosphite anion type Ris disclosed in our copending Application No 17206/53 (Specification Serial No 761,062), that contains as an additive an exaltant in the

form of a soluble salt of a simple short-chain saturated aliphatic dicarboxylic acid, and specifically sodium succinate. In carrying out the chemical nickel plating process, particularly in a continuous system such as disclosed in our copending Application No 19063/53 (Serial No. 785,693), it has been discovered that an initially stable plating bath becomes unstable after some use, and notwithstanding the content of the buffer, or the exaltant, or both, whereby the plating bath decomposes with the formation of the previously mentioned black precipitate It is believed that the formation of the black precipitate (the first visible manifestation in the plating bath of random reduction of the nickel cations) starts at the surfaces of suspensoids (solid particles of dust, microcrystalline precipitate of ferric hypophosphite, nickel phosphite, etc), present in the plating bath, and the presence of these suspensoids in the plating bath is evidenced by the observation of Tyndall beams when a shaft of light is passed through the clear filtered plating bath, even when freshly prepared. The present invention is predicated upon the discovery that such plating baths may be stabilized to a high degree, without material depression of the plating rates thereof, by the further addition thereto of a trace amount of certain water-soluble additives of dipolar molecular character. In accordance with the present invention there is provided a nickel plating bath which comprises an aqueous solution containing nickel ions, hypophosphite ions and an amount of a stabilizing additive so as not substantially to reduce the plating rate of the bath and so as to inhibit random decomposition of the bath, said stabilizing additive comprising a long chain aliphatic compound containing at least 6 carbon atoms in the aliphatic chain and being capable of forming an oriented hydrophobic film on the material to be plated. In the plating bath ofr the present invention the cation of the dipolar molecule is readily dissociated and the anion of the dipolar molecule forms with the metallic element of any suspensoids which may be present a water-insoluble product that is hydrophobic or water repellent. The presence of these suspensoids is undesirable and the purpose of the additive is to form hydrophobic films upon suspensoids that may be in the plating bath. The additive is capable of forming an oriented hydrophobic film on the surface of the material to be plated and since any additive which remains after the suspensoids have been coated will attach itself to the material to be plated, the amount of the additive present should be limited so as not to have an inhibiting effect on the surface of the object 70 being plated.

In accordance with the invention only a trace amount of the additive is placed in the aqueous solution in forming the bath Preferably, the long chain aliphatic compound 75 comprising the stabilizing additive of this invention contains not more than 18 carbon atoms, i e, 6-18 carbon atomns, in the aliphatic chain In general, the additive compound is selected from the class consisting of ali 80 phatic carboxylic acids and alkali metal salts and sulphates and sulphonates thereof unsaturated aliphatic amines and salts thereof, such as an amine acetate and unsaturated aliphatic long chain alcohols In large quan 85 tities the aliphatic radical present in the bath is a catalytic poison, and will considerably reduce the plating rate or stop plating altogether However at the proper concentration, the aliphatic radical prevents random 90 decomposition of the plating bath and the formation of the black precipitate mentioned. the proper quantity of aliphatic radical in the plating bath to achieve stability being not greater than 100 parts per 1,000,000 95 parts by weight of the plating bath, preferablv in the range 5 to 100 parts per 1,000,000 parts of the plating bath by weight. In accordance with the plating process of the present invention, the article to be nickel 100 plated and formed of a catalytic material is prepared by mechanically cleaning, degreasing and light pickling, substantially in accordance with standard practices in electroplating processes 105 With respect to the composition of the bath, it comprises an aqueous solution containing nickel cations, hypophosphite anions, a buffer or exaltant, and a stabilizing agent. For example, the nickel cations may be 110 derived from nickel chloride, and the hypophosphite anions may be derived from sodium, potassium, lithium, calcium mannesium, strontium or barium, hypophosphites, or various combinations thereof 115 Specifically a suitable bath may be formed in an exceedingly simple manner by dissolving in a hydrochloric acid-water solution nickel chloride and sodium hypophosphite, and then the buffer or exaltant and the 120 stabilizing agent are added thereto, as explained more fully hereinafter The desired p H of the bath is established by the eventual introduction thereinto of additional hvdrochloric acid and is appropriately adjusted 125 by the addition thereto of a weak alkali, preferably sodium bicarbonate. The terms "cation" "anion", and "ion" as employed herein, except where specifically noted, include the total quantity of the 130 786,175 corresponding elements that are present in the plating bath, i e, both undissociated and dissociated material In other words, 100 %) dissociation is assumed when the terms noted are used ir connection with molar ratios and concentrations in the plating bath. The stabilizing effects of the various organic compounds mentioned

were determined from a series of plating tests that were made employing a "standard" test plating bath having a volume of 50 cc and a temperature between 98 C and 100 'C Low carbon steel samples were plated that had a surface area of 20 cm 2 and that had been vapour-degreased, electro-cleaned, and pickled in a 10 % HCI solution The standard test plating bath was produced from a solution containing nickel as nickel hypophosphite ( 0 09 mole/litre), sodium hypophosphite ( 0 045 mole/litre), sodium succinate ( 0.06 mole/litre), sodium chloride ( 0 18 mole /litre), and enough water to make one litre, the peel having been adjusted to a value of 4.6 with pure Hl, whereby the nickel cation/hypophosphite anion ratio was 0 4. The stabilizing agents were then added to the standard test plating bath by measuring the proper volume from stock solutions containing 1,000 ppm thereof, and the plating rates (R) were measured in gm/cm 2/min. In these tests stability is indicated by the time in minutes that elapsed before "black precipitate" was formed, and the appearance of the nickel deposited upon the samples was ppm of sodium oleate Wt gain gms p H begin p H end Sample Appear Time to black ppt min. noted In describing the appearance of a 35 test sample, the following symbols are employed: B= Semi-bright (satin), BB =Bright, VB = Very bright, S= Smooth, SR= Slightly rough, R=Rough, D=Dull, and Sp= Spotted 40 Two "blank" plating tests were first run employing only the test samples in the standard test plating bath (without the addition of any stabilizing agent), with the following results: 45 Duration of test 10 min 60 min. Weight gain, gms 0 0948 0 1903 Plating rate Rx 104 4 74 Sample appearance B-S B-SR Time to black ppt None 20 mins 50 From the two above blank plating tests, it is apparent that the standard test plating bath is unstable since noticeable decomposition thereof takes place within 20 minutes; and hereafter a plating bath is considered "un 55 stable" if it decomposes within a time interval of 60 minutes. Comparable plating tests were then made employing the standard test plating bath containing as stabilizing agents the various 60 organic compounds mentioned, the stabilizing agents being added to the baths from stock solutions containing 1,000 ppm of the organic molecule. In a series of these plating tests employ 65 ing the standard test plating bath containing sodium oleate as the stabilizing agent, the following results were obtained:Stability test-60 minutes 10 0 1334 0 1376 4 58 4 58 2 80 2 63 BB-S BB-S 10 0.1401 4.58 2.73 RB-S 0.1384 4.58 BB-S 0.1469 4.58 BB-S In a series of these plating tests employ potassium oleate as the stabilizing agent, the ing the standard test plating bath containing following results were obtained:ppm of potassium oleate Weight gain, gms.

Plating rate Rxl O 4. Sample appearance Time to black ppt. p H begin p H end ppm potassium oleate Wt gain gins. p H 1 begin p H end Sample Appear. Time to black ppt min. (a) Rate test-10 minutes 0 25 50 0.0596 0 0577 0 0542 2.98 2 89 2 71 BB-S BB-S BB-S none 4.59 4 59 4 59 3.98 4 02 4 07 (b) Stability test-60 minutes None 10 0 1253 0 1379 4 58 4 58 2 780 2 65 BB-S BB-S 10 0.1382 4.58 2.66 RB-S 0.1392 4.58 2.67 BB-S 0.1483 4.58 2.62 BB-S 786,175 The foregoing plating tests employing the standard test plating bath containing either sodium oleate or potassium oleate establish that stabilization is achieved at 75 ppm. A series of these plating tests were conducted employing the standard test plating bath containing a high molecular weight iminodazoline ("Amine 0, manufactured by Alrose Chemical Co) as the stabilizine agent "Amine 0 " is fundamentally l Phydro 10 xyethyl-2-heptadecenivl-imino'dazoline of approximately 880 purity and in these plating tests the following results were obtained:(a) Rate test-10 minates 0 0 0649 3 25 ppm of " Amine 0 " Weight gain, gms. Plating rate Rxl O 4 Sample App. Time to black ppt. p H begin p H end Bath appear. ppm of " Amine " 0 Weight gain, gms. Sample App. Time to black ppt. p H begin p H end Bath app. In view of the foregoing plating tests employing in the standard test plating bath "Amine O " as the stabilizing agent, it will be observed that the stabilizing range is 5 0 ppm and above, with acceptable rates up to ppm. A series of these plating tests were conducted employing the standard test plating bath containing acetic acid salts of primary ppm of " Armac T" Weight gain, gins. Plating rate Rx 10. Sample app Time to black ppt. p H begin p H end Bath app. ppm of " Armac T" Weight gain, gms. Sample app Time to black ppt. p H begin p H end Bath app. 1 5 0.0538 0 0573 2.69 2 87 sc 0.0566 2.83 none 4.59 4 59 4 59 4 59 20 3.93 4 08 4 04 4 05 clear, green (b) Stability tests-60 minutes 0 1 5 10 25 50 0.1341 0 1361 0 1292 0 1248 0 1137 0 0995 25 BB-SR BB-S BB-S Sp-S Sp-S Sp-S 12 10 stable 4.61 4 61 4 61 4 61 4 61 4 61 2.52 2 66 2 88 3 00 3 31 3 58 clear,

green 30 fatty amines ("Armac T" manufactured by 40 Armour & Co, the word "Armac" being a Registered Trade Mark) as the stabilizing agent "Armac T" is fundamentally a tallow amineacetate consisting of 30 oq hexadecylamineacetate, 25 % octadecylamineacetate and 45 % octadecenylamineacetate and in these plating tests the following results were obtained:(a) Rate test-10 minutes U 1 5 10 25 50 50 0.0649 0 0657 0 0291 0 0177 0 0008 0 0005 3.25 3 29 1 46 0 89 0 04 0 03 BB-S BB-S Sp-S Sp-S Sp-S Sp-S none 3.25 3 92 4 29 3 40 4 58 4 59 55 5.59 4 59 4 59 4 59 4 59 4 59 Clear green-Slightly turbid Turbid, green-green(b) Stability tests-60 mintes 0 1 5 10 25 50 0.1286 0 1449 0 1345 0 0727 0 0140 0 0014 60 BB-S BB-S BB-S Sp-S Sp-S Sp-S 13 12 stable 4.61 4 61 4 61 4 16 4 61 4 61 2.71 2 52 2 69 3 79 4 41 4 54 clear, green Turbid green 65 In view of the foregoing plating tests employing in the standard test plating bath "Armac T" as the stabilizing agent, it will be observed that the stabilizing range is 5 0 ppm and above, with an optimum rate at ppm. In a series of these plating tests employing the standard test plating bath containing the isopropanol amide of oleic acid ("Emcol X-25 " manufactured by Emulsol Corp) as 75 the stabilizing agent, the following results were obtained: 786,175 ppm of " Emcol X-25 " Weight gain, gns Plating rate Rxl O 4 s Sample app Time to black ppt p H begin p H end Bath App (a) Rate test-10 minutes 0 10 0 0422 0 0436 2 11 2 18 ' BB-S BB-S 0.0444 2.22 none 458 4 58 4 58 4 58 413 4 13 4 12 4:14 clear, green ppm of " Emcol X-25 " Weight gain, gins Sample App. Time to black ppt p H begin p H end Bath app (b) Stability tests-60 minutes 0 1 0.1286 0 1506 BB-S BB-R 13 20 4.61 4 61 2.71 2 41 10 25 50 0.1441 0 1432 0 1462 0 1453 BB-S 30 55 Stable 4.61 4 61 4 61 4 61 2.55 2 56 2 52 2 54 clear, green In view of the foregoing plating tests employing in tthe standard test plating bath -Emcol X-25 " as the stabilizing agent, it will be observed that the stabilizing range is O.0 ppm and above. Tche minimum amounts of the different ones of these organic stabilizing agents that are required to achieve stabilization are a function of nickel cation concentration in the plating baths, whereby the minimum amount of the stabilizing agent that must be added thereto must be disproportionately increased as the nickel cation concentration in the plating bath is increased However, these minimum amounts of the different organic stabilizing agents are otherwise independent of the particular compositions of the plating baths with reference to other constituents This is probably due to the fact that they do not form complexes with such constituents as malic acid, lactic acid and amino-acetic acid Thus these organic stabilizing agents are very advantageous when used in proper amounts since they do

not decrease the plating rate of the plating baths over wide ranges and they tend to increase substantially the brightness of the plated bodies, and moreover they do not have any adverse action on the adhesion of the nickel plating upon the base metal of the plated bodies. In carrying out the present process in a continuous plating operation, it is recommended that trace quantities of the selected stabilizing agent be fed periodically or continuously into the plating bath along with the other regenerating chemicals (particularly the nickel cations and the hypophosphite anions) so as to keep the level thereof substantially constant and at that required, as previously explained For example, the simplest and safest procedure lis to select la stabilizing agent that is known to be active, and not objectionable with respect to decreasing the plating rate over a relatively wide range of concentration, and then to keep the level of concentration of the stabilizing agent within the effective range by the required 65 addition thereof to the plating bath along with the other regenerating ingredients, as noted above The temperature of the plating bath is generally above 90 'C and the ph thereof is in the range 3 0 to 5 5 70 Amounts of said stabilizing additive are added during the regeneration sufficient to maintain controlled trace amounts ithereof in the bath throughout the time interval during which the catalytic material to be plated 75 is contacted with the plating bath. In the appended claims the term "catalytic material" means any material which can be nickel-plated in an aqueous bath of the nickel cation-hypophosphite anion type with the 80 evolution of hydrogen gas at the catalytic surface, and includes a material comprising an element which is catalytic for the oxidation of hypophosphite anions as previously set forth herein, and materials comprising an 85 element which may be nickel-plated by virtue of the initial displacement deposition of nickel thereon either directly or through a galvanic effect, as previously set forth herein.

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* GB786176 (A)

Description: GB786176 (A) ? 1957-11-13

Polyester films and their production

Description of GB786176 (A)

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PATENT SPECIFICATION Date of Application and filing Complete Specification: May 20, 1955 No. 1 P Application made in United States of America on June 8, 1954. ^ O g / Application made in United States of America on Feb17, 1955. ___ i <Complete Specification Published: Nov 13, 1957. Inden eit aaoeptance:-Classes 2 ( 2)l, E( 2:612)9 and 1 IMI 1 E 0, Inteiniationsia Classification -b 329 d, D 03 m. COMPLETE SPECIFICATION Polyester Films and their Production We, E I Du PONT Ds E NEMOURS AND COMPANY, a Corporation organised and existing under the laws of the State of Delaware United States of America, located at Wilmington 98, Delaware, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: - This invention relates to self-supporting oriented polyester films of improved dimensional stability and to such films having an adherent substratum of a polymeric filmforming material and a water-permeable colloid layer The invention also relates to light-insensitive products

obtainable by such processes, to a photographic film having at least one water-permeable colloid silver halide emulsion layer disposed on such polymer coated polyester film either directly or by means of a water-permeable colloid anchor layer, and to the production of all the said materials. In United States Patent No 2,627,088, there is disclosed a process of preparing photographic flim including casting or extruding into the form of a self-supporting sheet of film, a molten highly polymeric ester of a dicarboxylic acid and a dihydric alcohol, said ester being capable of being formed into filaments which when cold drawn show by characteristic X-ray patterns molecular orientation along the fibre axis, coating at least one surface of the polyester film with an aqueous dispersion of a copolymer containing at least 350, by weight of vinylidene chloride, drying the coated film and biaxially orienting the coated film by stretching it at an elevated temperature A water-permeable colloid layer is then applied to the layer of copolymer to serve as an anchor layer for a colloid silver halide emulsion layer. Photographic film produce in accordance with the process of the aforesaid United States Patent has many useful properties Its mechanical strength and flexibility are excellent and it has excellent dimensional stability when exposed to temperatures below 90 WC. Water-permeable colloid silver halide emul 50 sion layers have strong adherence to the polymer-coated base film Such photographic film is useful as X-ray film, portrait film, motion picture film and for photographic purposes in general 55 Motion picture exhibitors are now using projectors which operate at higher temperatures than formerly, because of the use of larger viewing screens and three-dimensional pictures The perforated photographic film 60 used in such projectors is often raised to temperatures of 120 'C or higher, which causes a slight shrinkage in the pitch from one perforation to the next which, in turn, causes unsteadiness, chatter, vibrations and wobble 65 The distance between perforations decreases so that the teeth on the projection apparatus do not engage the perforations uniformly and accurately Moreover, the shrinkage may result in buckling of the film which causes 70 image distortion on the screen. The present invention provides polyester films with improved dimensional stability. By the expression "polyester" is meant a highly polymeric ester of a dicarboxylic acid 75 and a dihydric alcohol, the said ester being one which is capable of being formed into filaments which when cold drawn show by characteristic X-ray patterns molecular orientation along the fibre axis By the ex 80 pression "dimensionally stable" is meant that the film is substantially stable in dimensions under all normal

conditions of use and shows no significant shrinkage when exposed to a temperature of 120 'C for five minutes under 85 conditions of no tension By the term "biaxially oriented" is to be understood the condition of a film which has been stretched in each of two directions at right angles in either order or simultaneously, and the term 90 "biaxially orienting" refers to this stretching process. 69176 14685/55. t. 7 $ 8 786,176 According to the present invention a process for the production of a dimensionally stable polyester film comprises forming a sheet of film from a molten polyester (as hereinbefore defined), and particularly of a polyethylene terephthalate, biaxially orienting the film by stretching it in two directions at right angles at elevated temperature, heat-setting the film at a temperature from 150 'C to 210 'C under conditions such that no shrinkage occurs and modifying the heat-set film by heating it to a temperature of 10 CC to 150 'C for a period of 1 to 5 minutes while under a tension between 10 and 300 and preferably between 10 and 25 pounds per square inch When the film is to be used as a base for photographic purposes, the second heating operation can be carried out either before or after the application of a water-permeable colloid substratum for anchoring a water-permeable colloid silver halide emulsion layer to the polyester film. This second heat treatment, which is carried out at a temperature above the temperatures normally used in drying aqueous water-permeable colloid layers, relaxes the stresses in the biaxially-oriented film and markedly improves its dimensional stability. The amount of tension to be used for relaxing stresses in a particular polyester film will depend primarily upon the temperature to which it will be subjected in use In general, moreover, the tension will be increased, between the limits given above in proportion to the increase in the temperature of the heat treatment For example, in order to produce a polyester film which does not shrink more than 0 2 ' in dimensions when heated to 'C for five minutes, a tension of 175 pounds per square inch can be used at a temperature of 120 'C for a period of 5 minutes, or a tension of 295 pounds per square inch can be used at 1390 C for a period of 5 minutes. In one method of carrying out the invention, a molten polyester, e g, a polythylene terephthalate, is cast or extruded onto a suitable smooth surface and stretched longitudinally and laterally, in either order or simultaneously, at a temperature of 70 WC to 1200 C, heat-set at a temperature between 'C and 210 'C at a tension such that dimensions will be held constant, and then passed into a heating zone where it is heated to a temperature between 110 'C and 150 'C. for a period of 1 to 5 minutes under slight tension, whereby internal

stresses are relaxed. The casting or extrusion of the polyester into the form of a film and the stretching of the film can be carried out with any conventional apparatus for this purpose An especially useful extrusion apparatus is described in Specification No 772,148 and in Application Nos 2226155 and 25572/56 (Serial Nos. 779,645 and 779,646) An especially useful stretching apparatus is disclosed in Specification No 746,386. The polyester film may be composed of any polyester of a dicarboxylic acid and a dihydric alcohol of the type described in United 70 States Patent No 2,071,250 or may be composed of any of the high-melting difficultly soluble, usually microcrystalline, cold-drawing linear, highly polymerised esters of terephthalic acid and glycols of the series HO 75 (CH 2)COH, where ni is an integer within the range of 2 to 10 described in United States Patent No 2,465,319. The polyesters used in accordance with the present invention need not consist solely of 80 glycol units since some of the glycols react to form polyglycols and small percentages of units from such polyglycols can be present. For instance, when ethylene glycol is a reactant, the polyester may contain from 1 to 85 ' or more of units from diethylene glycol (i.e -CH CH OCH CH,O-units) Also when a mixture of glycols and polyglycols is used. e.g, ethylene glycol and diethylene glycol, the copolymers may contain a substantial 90 proportion of oxyethvlene units. If desired, the polyester film can be coated with a thin lay&r of an adherent film-forming copolymer prior to the biaxial stretching step or steps Suitable copolymers for this purpose 95 include ( 1) the vinylidene chloride copolymers containing at least 35- by weight of vinylidene chloride, e g, the poly(vinylidene chloride co acrylic or methacrylic ester or nitrile co itaconic acid) compounds described in 100 United States Patent No 2,627,088, ( 2) the polyisocyanates and polyisothiocyanates described in United States Patent No 2,698 242, ( 3) a polyester of ethylene glycol, terephthalic acid and a third component in the form of a 105 polyethylene glycol or a saturated aliphatic dicarboxylic acid, soluble in trichloro-ethylene in admixture with an organic polyisocyanate or polyisothiocyanate described in United States Patent No 2,698,241 and ( 4) 110 the polyesters described in United States Patent No 2,698,239 Such layers will be applied of the heat set, heat-relaxed film is to be used for the manufacture of photographic film In such case, it is desirable to 115 apply a thin layer of a water-permeable colloid, e g, gelatin or a synthetic colloid or mixture of the two, from an aqueous solution or dispersion and to dry the said layer at a temperature of 100 'C to 105

'C before the heat 120 relaxing operation. The polyester film may contain a pigment or dye to colour it any desired colour When the film is to be used as a photographic film base for X-ray film, it may be tinted green 125 or blue The copolymer layer may be similarly tinted and may contain an antistatic material Antistatic layers and antibalation layers can be coated on the surface of the film or on the copolymer layer 130 786,176 The invention is not limited to the particular layer of adherent film-forming copolymers described above (which are esssentially hydrophobic in character) as other adherent copolymers can be used as an anchoring substratum for a water-permeable colloid layer. Additional water-permeable colloids having a protective colloid action which can be used include water-soluble polyvinyl alcohol derivatives in general, e g, partially hydrolyged polyvinyl acetates, and mixed polyvinylchloride-acetates, hydrolysed interpolymers of vinyl acetate with unsaturated compounds, for example, maleic anhydride and acrylic acid esters Suitable colloids of the last mentioned types are disclosed in United States Patents Nos 2,276,322, 2,276,323 and 2,397,866 Other suitable colloids include hydrophilic partially substituted polyvinyl esters and acetals and the low substituted cellulose esters of saturated aliphatic monocarboxylic acids of 2 to 4 carbon atoms and low substituted cellulose ethers, e g, methylcellulose and ethyl-cellulose Additional natural colloids include casein, albumin, gum arabic, agar agar and polyglycuronic acid which are also anchored to supports by these new substrata. The casting or extruding of the polyester film, coating of the copolymer, heat-setting, colloid-coating and drying steps can be carried out in an apparatus of the type described in United States Patent No 2,627,088. The heat-relaxing step following the drying step can be carried out in another chamber 35 similar to the heat-setting and cooling zone o in the apparatus of the aforesaid patent, but is preferably carried out in a chamber where the film is in vertical paths and passes over and under rollers The heat-relaxing 40 zone can be heated near the entrance by infra-red lamps or electrically heated platens and then by means of hot air or superheated steam. The following examples will serve to illus 45 trate the invention but are not to be regarded as limiting it in any way:EXAMPLES I-III A molten ethylene glycol/terephthalic acid polyester having a melting point of about 50 255 C is extruded through an elongated orifice having the lips spaced about 90 mils apart onto a casting drum having a peripheral speed of about 90 inches per minute to form a film about 38 mils thick The film 55 is biaxially stretched, first longitudinally and then laterally, about 3 0 times in unit length and width at a

temperature of about 88 WC, heat-set under tension so that no shrinkage occurs, and then given a second heat treat 60 ment A sample of the resulting film and a sample of the film which did not receive the second heat treatment were heated to a temperature of 120 'C for a period of 5 minutes under no tension and the shrinkage meas 65 ured. The following results were obtained with varying conditions: Second heat treatment Shrinkage of Shrinkage Temperature of Temperature Tension lbs /sq Time in sample not of sample heat-set O C inch minutes subjected to subjected 0 C second heat to second treatment heat treatment Ex I 150 119 75 5 1 05 % 0 07 % Ex H 180 132 12 2 0 95 % 0 06 % Ex III 210 146 185 3 0 88 % 0 08 % EXAMPLES IV-VI A film of ethylene glycol/terephthalic acid polyester was cast as in Example I A surface of the cast film was provided with a layer about 1 8 microns thick of a vinylidene chloride/methyl acrylate/itaconic acid copolymer ( 90: 10: 2 by weight and made as described in Example I of United States Patent No. 2,627,088) and dried at a temperature of about 92 'C The coated film was biaxially stretched, first laterally and then longitudinally, about 3 0 times in unit width and length 90 at a temperature of about 88 WC, heat-set under tension so that no shrinkage occurred and then given a second heat treatment Samples of the film were tested as in Examples I-III and the following results were ob 95 tained:Second heat treatment Shrinkage qf sample not subjected to second heat treatment Shrinkage of sample subjected to second heat h-eahnetlt 119 75 5 0 83 % 0 09 % 132 12 2 0 9 % 0 05 % 105 210 146 185 5 0 92 % 0 10 % Temperature of heat-set rc. Temperature Tension Ibs /sq Time in 0 C inch minutes Ex IV Ex V Ex VI 786,176 The base films of Examples IV, V and VI, when provided with a thin gelatin substratum and coated with a gelatino-silver halide emulsion layer showed good anchorage and dimensional stability when developed washed, fixed and dried. EXAMPLE VII The process described in Example IV was repeated, substituting for the vinylidene chloride/methyl acrylate/itaconic acid copolymer of that Example a solution of the polyester of Example I of the United States Patent No 2,698,239 in trichloroethylene. The film was heat-set at a temperature of 180 C and the second heat treatment was at a temperature of 138 'C, a tension of 40 pounds per square inch and for a period of 2 l minutes A sample of the film, when tested as in Examples I-Il exhibited a shrinkage of only 0 09 < whereas a sample of the film which did not receive the second heat treatment exhibited, under the same conditions, a shrinkage of 1 42 EXAMPLE VIII The process described in Example IV was repeated substituting for the

vinylidene chloridel methyl acrylate/itaconic acid copolymer of that Example a mixture of a polyester and an organic polyisocyanate of Example I of United States Patent No. 2,698,241 The film was heat-set at a temperature of 1905 C, and the second heat treatment was at a temperature of 119 'C _ a tension of 150 pounds per square inch and for a period of 2 minutes A sample of the film, when tested as in Examples I-III exhibited a shrinkage of only 0 075 ',, whereas a sample of the film which did not receive the second heat treatment exhibited, under the samne conditions, a shrinkage of 118 <-,. EXAMPLE IX The process set forth in Example IV was repeated substituting for the vinylidene chloride/methyl acrylate/itaconic acid copolymer of that Example an organic polvisocyanate of Example V of United States Patent No 2,698,242 The film was heat-set at a temperature of 180 'C, and the second heat treatment was at a temperature of 1329 C, a tension of 12 pounds per square inch and for a period of 2 minutes A sample of the film, when tested as in Examples I-III exhibited a shrinkage of only 0 11 C ', whereas a sam Dle of the film which did not receive the second heat treatment exhibited, under the same conditions, a shrinkage of 0 85 ;. The uncoated biaxiallv oriented, heat-set heat-relaxed polyester films obtainable in accordance with the invention have excellent dimensional stability and are useful for many purposes where a dimensionally stable self-supporting film is desired Among such uses are measuring tape (where variation in dimension of the tape after the divisions of length have been marked thereon will result in inaccurate measurements a residual shrinkage of 1 in the tape resulting in an error of as much as 1 foot in a 100 feet tape measure), transparent windows for envelopes (where even slight shrinkage will cause 70 buckling of the envelope in an undesirable manner), bottle, ap and other container liners where shrinkage after the bottle or container is closed may cause lealafe of the contents). laminations with other ma-terials (where dif 75 ferences in shrinkage of tle several layers wiil result in warping and uneven bending of the composite structure package wrapping mnaterial, as for confectionery cosmetics, foods and other materials (where shrink 80 age of the wrapper subsequent to the wrapping may cause crack ino and tearing of the wrapper if originally tightly wrapped or -may cause an unsightly appearance if originally loosely wrapped to allow for 85 shrinkage), storm window substitute for glass (where shrinkage of a Fat tightly attached pane or sheet may cause tearing) dials drafting instruments scales and reticles (where unchanging calibration is critical) These and 90 many other uses for the polyester films obtained in accordance

with this invention are described in United States Patent No. 2,686,931. Various radiation-sensitive materials may 95 be coated onto the anchoring colloid layers of the light-insensitive films made in accordance with this invention In addition to lightsensitive silver salts, such as silver chloride. silver bromide, silver chloride-bromide silver 100 chloride-iodide and similar mixtures, there may be used bichromated hydrophilic colloids, e g, albumin, gelatin gum arabic. polyvinyl alcohols or glue The light-sensitive layers, of course are applied in the ab 105 sence of actinic radiations Non-diffusing colour formers, dye intermediates or dyes may be present in such layers Other materials which mav be coated include 5 i 1 ht-sensitive iron salts and diazonium compounds 110 with or without coupling con Inonents With certain of these light-sensitive materials e g the diazo compounds the binding agent may have a low sensitivity to water Thus polyvinyl acetate or a cellulose acetate may be 115 used as the colloid binder. The radiation-sensitive copolyrmer-coated biaxially oriented polyester films made in accordance with this invention can be used for any purpose including radiography por 120 trait photography, colour photography, lithography and motion picture purposes The non-light-sensitive base films are also useful for projection screens, glazing (laminations for windows and surface protection) 125 The production of dimensionally stable self-supporting polyester films in accordance with this invention is simple, dependable and easily controlled, it does not require complicated or expensive equipment and can be 130 786,176 carried out on a semicontinuous scale The invention is of particular value in providing photographic films bearing at least one lightsensitive layer on a polyester base that is dimensionally stable under conditions of processing and use even at temperatures above -stretching temperatures.

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* GB786177 (A)

Description: GB786177 (A) ? 1957-11-13

An improved weld nut

Description of GB786177 (A)

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BE551321 (A) FR1156716 (A) BE551321 (A) FR1156716 (A) less Translate this text into Tooltip

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

We, G K N GROUP SERVICES LIMITED, a British Company, of London Works, Smethwick, in the County of Stafford, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to the class of nuts which has become known under the term "weld nuts" and in which a nut is provided on one end face with a plurality of small projections so that when it is desired to secure the nut to a metal plate, the projections can be fused with the metal of the plate by means of an electric current passed between suitable electrodes, through the nut and the plate, pressure also being applied to the nut, so that the nut becomes welded to the plate. There have been in the past certain proposals for weld-nuts of square shape having four projections, one at each corner of the nut, and such projections have been either of hemo-spherical form or angular form These are not entirely satisfactory from the point of view of obtaining a good weld because they do not provide a good area of contact with a plate for welding purposes and, particularly in mass production, they cannot be relied upon to provide welding projections which are all of equal height from the base of the nut, and for good

welding it is essential that the projections be all of equal height. It is the object of the present invention to provide an improved weld nut which will be free of these objections. According to the present invention we provide a weld nut of square form having on one end face an axially projecting spigot for locating the nut over a preformed hole in 7869177 the plate to which it is to be attached and four welding projections which are formed as arcuate parts of an annular ring having 45 its centre coincident with the axis of the nut. The invention is illustrated in the accompanying drawings wherein:Figure 1 is a perspective view of a nut. Figure 2 is a plan view on the top 50 Figure 3 is a side view. Figure 4 is a section taken diagonally. In this example of a weld nut constructed in accordance with the present invention the body of the nut is of square form and is 55 provided with a centrally disposed hole extending between the end faces 10 and 11 and provided with the usual form of screw thread 12. On one end face 10 there is formed a 60 locating spigot which takes the form of a circular ring or boss 13 projecting axially from this end face and concentric with the threaded hole and this locating spigot serves to engage within a prepared hole in the plate 65 to which the nut is to be attached so as to locate the nut in the correct position for the subsequent welding operation The internal screw thread extends also through the interior of this locating spigot 70 Also on this end face 10 the otherwise flat face of the nut is provided with four welding projections 14 and these are formed at the four corners of the nut as parts of an annular ring (see Figure 2) which has its 75 axis coinciding with the axis of the threaded hole such that four parts of this annular ring appear as raised projecting ribs 14 which extend across the four corners of the nut. At each corner the rib so formed is spaced 80 away from the extreme corner point 15 of the face of the nut and is also spaced away from the locating spigot so as to provide an air gap between the welding projection and PATENT SPECFICATION Inventor: -NORMAN HECTOR NEWTON. Date of filing Complete Specification: June 11, 1956. Application Date: July 8, 1955 No 19769/55. Complete Specification Published: Nov 13, 1957. Index at Acceptance -Class 89 ( 1), A 7. International Classification:-FO 6 b. COMPLETE SPECIFICATION. An Improved Weld Nut. 786,177 the locating spigot which prevents molten metal from entering the threaded interior of the nut during the welding operation. As the four raised ribs 14 at the corners of the nut are part of a

common annular ring there is a guarantee that they will be of equal height which is essential for good welding characteristics. At its other end the face of the nut may be provided with a shallow recess 16 around the opening of the threaded hole for the purpose of concentrating the flow of current during the welding operation in the outer regions of the nut body so as to avoid any damage due to overheating and deformation of the thread form as is more fully explained in the Specification of our co-pending Application No 16113/55 (Serial No 775,724). In previous proposals for weld nuts of square form having four projections these projections have been provided by separate and independent forms on a tool thus giving no guarantee of equality of height between the projections whereas with the present invention the four projections can be provided by means of tool forms which are part of a common ring which ensures an equality of height in all the projections produced on the face of the nut.

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* GB786178 (A)

Description: GB786178 (A) ? 1957-11-13

Bis-mercaptomethyl aromatic compounds

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete,

up-to-date or fit for specific purposes.

COMPLETE SPECIFICATION Bis-Mercaptometbyl Aromatic Compounds We, Esso RESEARCH AND ENGINEERING COMPANY, a corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Elizabeth, New Jersey, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to improvements in or modifications of the process described in our copending Application, No. 36131/54 (Serial No. 783,546). In the said cop ending application we have described a method for the production of bismercapto aromatic compounds such as bistnercaptomethyl durenes by reacting a bishaloaromatic compound such as bis-chlorb methyl durene with a thiocompound such as a thiourea, a thiocarbamate or a xanthate to form a thiouronium, thiocarbamate or xanthate derivative and then converting this compound to the mercapto derivative by hydrolysing the talouronium compound with aqueous alkali or treating the thiocarbamate or xanthate com- pound with ammonia. The bis-haloaromatic compound used as the starting material may be represented by the formula ZCH2.Ph.CH2Z wherein Z is chlorine, bromine or iodine, and Ph is a phenylene radical or a phenylene radical substituted with 1 to 4 methyl groups. This type of material can be prepared in a variety of ways as described, for instance, by M. J. Rhoad and P. J. Flory, J.A.C.S. 72:2216 i(1950). Bischloromethyl-2,3,5,6-tetramethylbenzene, also known as bis-chloromethyl durene and hereafter represented for the sake of simplicity by the formula CH2.X.CWCl, is by far the preferred material because of the unusual prb perties attributable to its fully substituted ring structure. However, other known aromatic bis-chioromethylated in the para position such as para-bis-chloromethyl benzene or 2,5-bischloromethyl-1,4-dimethyl-benzene may be used similarly as a starting material for linear fiber forming resins. Moreover, where the linear nature of the final condensate is not of paramount importance e.g. in molding resins or in insecticides, the two halomethyl groups need not be in the para position and in such an event bis-halomethylated mixed xylenes represent a particularly useful raw material. instead of the chloromethyl derivatives it will be understood that the analogous bromomethyl or iodomethyl derivatives can be used similarly.

According to the process of the above Co- pending application the mercaptan group may be introduced into the aromatic molecule by reacting the above halo compound with a suitable thiocomnound represented bv the formula <img class="EMIRef" id="026598823-00010001" /> wherein Q is an amino group NR2 or an allroxy radicalORV, and Y is an amino group - NR1V or thiol salt radical - SM, RIV being hydrogen or an alkyl or aromatic radical of 1 to 8 carbon atoms such as methyl, propyl, octyl, phenyl or xylenyl, R7 being an alkyl or aromatic radical of 1 to 8 carbon atoms, preferably of 1 to 3 carbon atoms, and M being sodium, potassium or an ammonium radical The principal examples of such reagents are thiourea, CS(NH2),, alkali metal thiocar- bamates such as sodium dithiocarbamate, NaS.CS.NH2, and the alkali metal alkyl xanthates such as potassium ethyl xanthate, KS.CS.OC2H,. Of coarse, depending on economic considerations, various other alkyl or aryl substituted homologues of any of the foregoing types of compounds can be used, e.g., tetramethyl thiouree, CS(NMe2)2, ammos nium diisopropyl dithiocarbomate, NH4S. CS .N(i-C3H7)2, diphenylthiocarbamic acid phenyl ester, Ph2N.CS.OPh, or sodium octyl xanthate, NaS.CS.OCsH,7. As an illustration bis-chloromethyl durene can be condensed with an alkali metal alkyl xanthate as follow: - (1) ClCH2.X.CH2Cl+ 2KS.CS.OR-- > RO.CS.SCH2.X.CH2S.CS.OR+2KCL The bis-alkyl xantbomethyl aromatic com pound produced as an intermediate in the process of this invention will have the formula I, shown above, wherein X represents a phenylene, dimethyl phenylene, trimethyl phenylene or tetramethyl phenylene group and R represents an alkyl radical of 1 to 8 carbon atoms. The resulting bis - alkyl xanthomethyl aromatic intermediate can then be reacted with ammonia to yield the desired bismercaDtan: - <img class="EMIRef" id="026598823-00020001" /> (2b) RO.CS.SCH.X.CWS.CS.OR+ 2NH, oHS.C:H2.X.CH2SH+ by-products (e.g. xanthogen amide etc.). The use of the base, referred to in the above cop enduing application for the treatment of the bis-alkyl xanthomethyi aromatic compound acording to the process of the above copending application has the disadvantage that unless special precautions are taken substantial amounts of by-products insoluble in allmali are formed and thus reduce the yield of the desired bis-mercaptan. It has now been found that if a weak base is used improved yields can be obtained with a reduction in the amount of insoluble compounds. The term weak base as used herein does not include ammonia and refers

to ionisable bases which are weaker bases, in aqueous solution, than sodium hydroxide. Examples d such weak bases are acid salts of hydrogen sulfide such as potassium hydro gen sulfide, ammonium hydrogen sulfide, and sodium hydrogen sulfide. The present application relates to an improvement in or modification of the process described and claimed in Application No. 36131/54 (Serial No. 783,546) for preparing a dimercaptan which comprises reacting one mole of an aromatic dihalide, having the formula ClCW.X.CH,G wherein X is a phenylene, momomethylphenylene, dimethyl phenylene, trimethyl phenylene or tetramethyl phenylene group, with 2 moles of an alkali metal alkyl xanthate, separating the resulting aromatic xanthate product, heating the separated aromatic xanthate product with a weak base in a ratio of at least 2 moles of weak base per mole of said aromatic xanthate until a major proportion of the xanthate is converted to the dimercaptan, dissolving the resulting dimercaptan, in hot aqueous alkali, separating residual undissolved solid from the liquid soludon, and precipitating the dimercaptan from the solution. The reaction between the aromatic dihalide and the alkali metal alkyl xanthate is preferably carried out at 30 to 50" C. EXAMPLE The xanthomethyl derivative of bischioro methyl durene was obtained by reacting bischloromethyl durene with an alkali metal alkyl xanthate such as potassium ethyl xanthate, and sodium propyl xanthate as described below. A three-way flask equipped with a stirrer, a return condenser and a thermomtr, was charged with 211.2 gms. (1.32 mole) of potav sium xanthate, and 900 ml. dimethylformamid as the preferred solvent. Other sol. vents which can be used in its stead include formamide, dioxane and chloroform, though these will generally give much poorer yields. 138.6 gms. (0.6 mole) of bis-chloromethyl durene was slowly added to the mixture of xanthate and dimethyl formamide with stirring and sufficient cooling to keen the temerature at a moderate level, that is, at about 30 to 40 C. Higher temperatures at this stage have an adverse effect on yield. When all the dihalide had been added, stirring at 40 C. was continued fcr three additional hours. At this point, the mixture was cooled to a temperature below 0 C. specifically to about - 5 C., and filtered. The precipitated aromatic xanthate was slurried with water several times to remove the excess of potassium xanthate and the potassium chloride formed. When air dried, the bis-ethylxanthomethyl durene product consisted of

240 gms. of an almost snow-wllite powder melting at 179 C. On recrystallization from dioxane it melted at 184 C. Compared with a theoretical yield of 246 gms. the actual yield was almost quantitative. This compound was than converted into the desired bis-mercaptan as described below. A 12-liter four-neck round bottom flask equipped with a stirrer, condenser and a thermometer was charged with 3000 ml. of absolute ethyl alcohol and 1500 ml. of an ethyl alcohol solution of potassium hydrogen sulfide containing 0.21 grams KHS per ml. of solution The mixture was heated to 75-80 C. and 804 grams of bis-ethylxanthomethyl durene prepared as described above was added to it The resulting mixture was then heated and refluxes for 1.5 hours to form the dimercaptan. At this stage 400 ml. of a 30% aqueous solution of sodium hvdroxide was added and the mixture was reflexed for an additional hour. Finally the mixture was poured into about thre times its volume of ice water acidified with concentrated hydrochloric add until neutral as determined by a Congo Red indicator, and filtered. The separated precipitate was reslurried several times in water and air dried for three days. The air dried material was distilled under a pressure of 1 mm. Hg. 331 grams of a fraction boiling at 165--170" C. at this pressure was recovered, leaving a small amount of higher boiling residue. The recovered distillate consisted of pure bis-mercaptomethyl durene having a melting point of 150 to 152 C. and corresponding to a yield of 82.3% based on bisxanthomethyl durene. A substantially better yield could be obtained with more careful handling. The purity of the product was confirmed by elemental analysis. The dimercaptan makes an ideal intermediate for the preparation of linear polymers by condensation of the former with bifbnc- tional reactant such as diacids, diacid chlorides, diolefins and dialdehydes. The polymerization or condensation is best carried out in an inert solvent such as xylene, toluene or ethylene chloride. For instance, the dimercaptan may be condensed with adipyl chloride while in solution in xylene. To bring about the condensation the reaction mixture is heated in the absence of oxygen, e.g. in a nitrogen or carbon dioxide atmosphere, until no more hydrogen chloride is given off. At the beginning of the reaction, the mixture is homogeneous but later becomes turbid, and finally the polyester precipitates as a snowwhite powder. On completion of the reaction the mixture is filtered, and the precipitate air dried either directly or, if quick drying is desired, after washing with ether. The polyesters have a melting point above 200 C. They can be readily cold drawn to produce strong colorless filaments. Various mixtures of two or more mercaptans e.g. of bis-mercaptomethyl benzene and

bis-mercaptomethyl durene, and/or of add chlorides, e.g. adipic and terephthalic chloride, may be used to modify the properties of the resins, e.g. to lower the melting point and so facilitate extrusion. What we claim is : - 1. An improvement in or modification of the process described and claimed in Application No. 36I31/54 (Serial No. 783,546) for preparing a dimercaptan which comprises reacting one mole of an aromatic dihalide, having the formula ClCH2.X.CH2Cl wherein X is a phenylene, monomethyl phenylene, dimethyl phenylene, trimethyl phenylene or tetramethyl phenylene group, with 2 moles of an alkali metal alkyl xanthate, separating the aromatic xanthate product, heating the separated aromatic xanthate product with a weak base in a ratio of at least 2 moles of weak base per mole of said aromatic xanthate until a major proportion of the xanthate is converted to the dimercaptan, dissolving the resulting dimercaptan in hot aqueous, alkali separating residual undissolved solid from the liquid solution, and precipitating the dimercaptan from the solution. 2. A process as claimed in Claim 1 wherein the weak base is an acid salt of hydrogen sulphide. 3. A process according to Claim 1 or 2 wherein the weak base is potassium hydrogen sulphide, ammonium hydrogen sulphide or sodium hydrogen sulphide. 4. A process as claimed in any of Claims 1 to 3 wherein the separated aromatic xanthate product is heated with the weak base in the presence of ethyl alcohol. 5. A process as claimed in any of Claims 1 to 4 wherein the reaction between the aromatic dihalide and the alkali metal alkyl xanthate is carried out the presence of dimethyl formamide, formamide, dioxane or chloroform. 6. A process as claimed in any of Claims 1 to 5 wherein the reaction between the aromatic dihalide and the alkali metal alkyl xanthate is carried out at 30 to 50 C. 7. A bis-alkyl xanthomethyl aromatic compound having the formula RO.CS.SCH2XCH2 S.CS.OR wherein X represents a phenylene, monomethyl phenylene, dimethyl phenylene, trim ethyl phenylene or tetramethyl phenylene group and R is an allyl radical of 1 to 8 carbon atoms. 8. The improvement in or modification of the process described and claimed in Specification No. 36131/54 (Serial No. 783,546) substantially as hereinbefore described with particular reference to the example.