4766 4770.output

* GB785173 (A)

Description: GB785173 (A) ? 1957-10-23

Amide-like derivatives of lysergic and isolysergic acids

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PATENT 3 SPE CI I CI ON SPECIFICATION i M a S Date of Application and filing Complete Specification: Jan 13, 1956. E W v No1252/56. Application made in Switzerland on Jan 21, 1955. Application made in Switzerland on Dec 7, 1955. Complete Specification Published: Oct 23, 1957. Index at acceptance:-Class 2 ( 3), C 3 A 14 A( 3 D: 5: 6: 8 D). International Classification:-CO 7 c, d. COMPLETE SPECIFICATION 785,173 Amide-like Derivatives of Lysergic and Isolysergic Acids We, SANDOZ LTD, of Lichtstrasse 35, Basle, Switzerland, a Swiss Body Corporate, do hereby declare the invention, for whichwe 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 a process for the production of new amide-like derivatives of lysergic acid and of isolysergic acid These new amide-like derivatives are also referred to herein as lysergic acid amides and, isolysergic acid armides; they have blood pressure lowering and sedative properties.

It has been found that hitherto unknown amide-like derivatives of lysergic acid and isolysergic acid having the general formula I: Cg 5 M /\ / wherein -es 2-eg A Xv R = { 2 / /2 5-C>/or /0 are obtained by reacting isolysergic acid azide with amines having the general formula II: II, wherein R has the above significance, and isolating from the resulting mixture the lysergic acid amide and isolysergic acid amide. Amide-like derivatives of lysergic acid and = isolysergic acid have already been known for some time (see for example A Stoll, Oest. Chemiker-Ztg 53, 73, 101 l 1952 l) For lPaice 3 s 6 d l example the naturally occurring ergot alkaloids of the ergotamine and ergotoxin group and their dextro rotatory isomers are amidelike derivatives of the said acids; they are characterised by an acid amid-like linkage of 35 the free amino group of a peptide residue which is made up of three amino acids, with the carboxylic acid group of the acid component Although the said ergot alkaloids have not hitherto been capable of synthesis 40 owing to the complicated structure of the peptide residue, acid amide-like mono-, diand tripeptides of the lysergic acids series having a simpler structure have already been synthesized (compare A Stoll, A 45 Hofnaann, E Jucker, Th Petrzilka, J. Rutschmann and F Troxler, Helv Chim. Acta 33, 108 l 1950 l) In other amides of lysergic acid series which are available by synthesis, for example in ergobasine, its 50 isomers, homologues and derivatives (A Stoll and A Hofmann, Helv Chim Acta 26 944 l 1943 l), the basic component is an aliphatic or aryl-aliphatic amino alcohol or an aliphatic amine All the above mentioned hitherto 55 " known amide-like derivatives of the lysergic acid series have one feature in common, i e. the carboxylic acid group of the acid component is linked in acid amide-like manner with an amino group forming part of a straight 60 chain On the other hand, amide-like; derivatives of the lysergic acd series in which the carboxylic acid group is linked with an amino group which is a member of a heterocyclic compound, have been unknown up to 65 now Such last mentioned amides have only become accessible by means of the process of the present invention. -In accordance with the present invention a process for the production of amide-like 70 derivatives of lysergic acid and isolysergic acid having the general formula I 46 dg 5 A 06 t CO #V/K> wherein \Ca >f\j_ x Ll ' tw. Aq / U'\ If M 2 i 2 785,1 j 3 =, O X or-eldxf, -emit or -e Nl is characterized in that isolysergic acid azide is reacted with an amine having the general formula II elfll wherein OR has the above meaning, and' the lysergic acid amide and the isolysergic acid amide are separated from the resulting mixture of these two components, the

reaction of the amine and the said azide being effected in solution Preferably the reaction is effected at a temperature Of from ambient temperature to 700 C. For example, the process of the present invention, is effected in such a manner that isolysergic acid azide dissolved in an organic solvent is allowed -to react with an amine of the formula II at room temperature or at a slightly higher temperature Solvents which may be used are not only Tinert organic liquids but also the amine used for the reaction, in which case an amount of amine in excess of the theoretically required quantity for the reaction' is added The end product,; which is a mixture of a lysergic acid amide and anx isolysergic acid amide, is isolated by' evaporating the solvent or the excess of amine in' a vacuum and the said two isomeric amides are se parated from this mixture by known methods, for example by chromatography on aluminium oxide The isolysergic acid azide which is used as starting material may be' produced in accordance wviih the 'method desdsribed -by A Stoll and A Hofmann in Helv Chim Acta 26, 944 ( 1943). The amide-like derivatives of lysergic acid and isolys'ergic' acid which may -be obtained by the process of the present invention are compounds which are solid at ambient temperature,minos-tof them are crystalline and form well defined crystalline salts with: acids. They have interesting phamacological properties as they have a definite effect on vital centres' of the organism Ti particular they affect those portions of the medulla oblongata and probably also aialogous portions of the brain which are situated higher up For example in the case of the pyrrolinide and the pyrrolidide of lysergic acid amounts of 10-20 y/lkg administered intr-avenously to dogs and cats lead to a reduction of the blood pressure and a decrease in rate of the heart beat The morpholide and the piperidide of lysergic acid have qualitatively the same effect but in reduced measure However, these derivatives have a stronger effect on breathing, in particular the morpholide causing a remarkably great decrease and flattening in the rate of breathing The effect on vital portions of the animal organism by the above mentioned compounds are further noticed by the influence they have on the body temperature which may be raised or lowered, depending on the animal species. Large amounts may cause vomiting; for example 100 ylkg of the pyrrolidide to dogs causes regular vomiting The above lysergic acid derivatives have no pronounced adrenolytic effect but they stimulate the uterus, but to a lesser degree than ergobasine or methylergobasine The new derivatives of lysergic acid, furthermore, have a pronounced retarding effect -towards serotomn. Some of the new compounds produced by the present process may be

used-therapeutically for the treatment of hypertonia. A particularly important property of the said new compounds from a therapeutic point of view is the good resorbability of the substances On administering parenterally one single effective dosage amounts 0 2 to 0 3 mg while a similar effect is obtained by oral administration of approximately twice the said amount. The following examples illustrate the invention without, however, limiting it; all temperatures are statedi in degrees centigrade and all percentages are percentages by weight. EXAMPLE 1. A solution of 10 g of isolysergic acid azide in 50 cc of pyrrolidine which had been produced at O e, is heated fof one hour to 600, the excess of pyrrolidine is -evaporated in a 95 vacuum, a solution of the residue in chloroform is extracted with an aqueous solution of sodium bicarbonate and the-chloroform solution which had been dried over sodium sulphate is evaporated in a vacuum The 100 residue ( 10 5 g) is dissolved in absolute chloroform and chromatographed on a column of 500 g of aulminium oxide On washing with absolute chloroform 7 5 g of lysergic acid pyrrolidide are eluted 105 The compound crystallizes from benzene in the form of leafy crystals containing solvent of crystallization and having a melting point of 100-110 ; on crystallizing from ethyl acetate pointed prisms are obtained which 110 melt at 1810 lal'2 = + 25 ( 1 2 % concentration (in pyridine) -. C Antyask C O H 23 HON, -321 4 Calculatedt C% 7473 H% 7 21 N% 13 08 Found: 74 78 7 16 13 16 115 The comipomund is soluble in water only with great -difficulty but forms easily soluble, 785,173 785,173 3 easily crystallizable salts, for example the dimaleate; the last mentioned salt crystallizes on the addition of an equimolecular amount of base to the acid in 5 times& the amount 6 of methanol to form elongated prisms having a melting point of 204-206, lCl,20 = + 350. ( 0.5 % concentration in water). On continuing chromatography with chloroform containing 1 % of ethanol, 2 3 gof isolysergic acid pyrrolidide are eluted. The compound crystallizes from acetone in the form of plates having a melting point of 202-203 , lOlC 2 O_ + 1939 ( 0 5 concentration in pyridine). Analysis: CQOH,2 ON = 321 4 Calculated: C% 74 73 M 1 % 7 21 N% 13 08 Found: 7495 7 25 13 26 The compound is soluble in water with difficulty. EXAMPLE 2. A solution of 10 g of isolysergic acid azide in 50 cc of tetrahydrofuran is mixed with 2 cc of piperidine, the mixture is warmed for two hours to 500, the solvent is evaporated and a solution of the residue in ethyl acetate is extracted with aqueous sodium

bicarbonate solution The residue resulting from the evaporation of the dried ethyl acetate solution ( 11 g) is dissolved in benzene and is chromatographed on a column of aluminium oxide 7 2 g of lysergic acid piperidide are eluted by means of absolute benzene It is not possible to obtain lysergic acid piperidide in the form of the free base as a crystalline substance The amorphous compound is very easily soluble in most organic solvents but is practically insoluble in water It forms crystalline water soluble salts Lysergic acid _piperidide D-tartrate On, mixing equivalent amounts of lysergic acid piperidide and D-tartaric acid in 5 times the amount of methanol the D-tartrate crystallizes in the form of needles having a melting point of 145-1500 l O JlJ = + 15 ' ( 04 % concentration in water) Analysis: (C,,H-,50 N),, 04 H 060 = 820 9 Calculated: C% 67 29 H% 6 88 N% 10 24 Found: 67 58 7 10 10 35 It is possible to obtain lysergic acid piperidide in the amorphous but pure state from the tartrate lalJ,20-180 ( 0 5 % concentration in pyridine). On continuing chromatography with benzene containing 5 % of methanol, 3 0 g of isolysergic acid piperidide are eluted The compound crystallizes from methanol in the form of polyhedrons containing solvent of crystallization and having a melting point of 137-140 lalD 20 = + 1900 ( O 51 % concentration in pyridine). Analysis: C 21 H 1,5 ON, Calculated: C% 75 18 H% 7 52 N% 12 54 Found: 75 29 7 82 12 38 EXAMPLE 3. A solution of 10 g of isolysergic acid azide 65 in 50 cc of morpholine which had been produced at 00, is left to stand for 10 hours at room temperature, the excess of morpholine is evaporated in a vacuum, a solution of the residue in chloroform is extracted with an 70 aqueous solution of sodium bicarbonate and the dried chloroform solution is evaporated in a vacuum The residue ( 10 5 g) which conrsists of a mixture of lysergic acid morpholide and isolysergic 'acid morpholide, is dissolved 75 in absolute chloroform and brought onto a column of aluminium oxide By means of absolute chloroform 7 0 g of lysergic acid morpholide are eluted; this material is crystallized from benzene in the form of 80 plates containing solvent of crystallization and having a melting point of 1160. f I Do 2 r= + 44 ( 0 2 % concentration in chloroform),. Analysis: COH,,0,N, = 337 4 85 Calculated: C% 71 19 H% 6 87 N% 12 46 Found: 71 27 6 84 12 16 The compound is easily soluble in most organic solvents, but soluble in water with difficulty It forms well crystalline, easily 90 water soluble salts with acids. The D-tartrate of lysergic acid morpholide crystallizes from methanol in the form of needles having a melting point of 1800. -x D 2 = + 230 ( 0 3 % concentration in water) 95 On dissolving equimolecular amounts of base and maleic acid the

dimaleate-crystallizes in the form of needles having a melting point of 2070. Analysis: COH 50,N C 4 H 4 04 = 453 48 100 Calculated: C% 63 56 H% 6 00 N% 9 27 Found: 63 49 5 99 ' 9 23 On continuing chromatography with chloroform containing 2 % of ethanol, 3 1 g of -isolysergic acid morpholide are eluted 105 = The compound crystallizes from ethyl acetate or acetone in the form of thin plates having a melting point of 1880 lHD 20 = + 2130 ( 0.2 % concentration in chloroform). Analysis: C 20 H,,02 N, = 337 4 110 Calculated: C% 71 19 H 1 % 6 87 N% 12 46 Found: 70 90 6 95 12 51 EXAMPLE 4. cc of, pyrroline are added to 10 g of Disolysergic acid azide and heating is effected 115 for one hour at 600 The excess of pyrroline is evaporated in a vacuum,, the residue is dissolved in chloroform containing 0 51 % of ethanol and is chromatographed on 1000 g of aluminium oxide 120 Using chloroform containing 0 51 % of ethanol the D-lysergic acid pyrrolinide passes through the column first This compound could not be obtained as the free base in crystalline form It is easily soluble in ether 125 and practically insoluble in water It forms 785,173 a water soluble salt with maleic acid maleate crystallizes in the form of needles or The d cmaleate of D-lysergic acid pyrro hexagonal prisms Melting point 207-212 linide On mixing equimolecular amounts of with decomposition' la ID 2 O= + 390 ( 0 5 % D-lysergic acid pyrrolinide and maleic acid in concentration in 50 % aqueous ethanol). 10 times the amount of methanol, the diAnalysis: C 2 o H 21 ON, C 4 H 4 04 -Calculated: C% 66 19 RP/% 5 79 O % 18 37 N% 9 65 Found: 66 31 5 86 18 40 9 38 D lysergic acid pyrrolinide may be obtained in amorphous but pure state fromi 15, its dimaleate l)jj 20 = + 57 ( 0 6 % concentration in pyridine). Analysis: C 20 H 2,0 N. Calculated: N% 13 2 Found: 13 4 Chloroform containing 1 % of ethanol effects elution of D-isolysergic acid pyrrolinide -=

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* GB785174 (A)

Description: GB785174 (A) ? 1957-10-23

A process for the production of emulsions

Description of GB785174 (A) Translate this text into Tooltip



x 3 1: _ PATENT SPECIFICATION Date of Application and filing Complete Specification Jan 19, 1956. No 1861/56. Application made in United States of America on Jan 26, 1955. Complete Specification Published Oct 23, 1957 Index at Acceptance:-Class 2 ( 7), T 6 D( 2: 8: 9: 11), T 6 (F 1: F 2: G 1: G 3: H 1: J 1). International Classification: -CO 8 g. COMPLETE SPECIFICATION A Procests for the Production of Emj jioiisWe, MIDLAND SILICONES LIMITED, a British company, of 19, Upper Brook Street, London, W.1, 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 emulsion polymerisation of organosiloxanes. One of the problems which has not heretofore been solved in the organosilicon field is a good process of preparing stable emulsions of extremely high molecular weight siloxanes, i.e, siloxanes which would be of sufficiently high molecular weight t Q make suitable protective coatings This has been accomplished heretofore after a fashion by first dissolving, the siloxane in a solvent and then emulsifying the solution However, this process has disadvantages inherent to the use of solvents Furthermore, such emulsions are not particularly stable Emulsified coating compositions are widely employed in the organic

resin art and the great advantages of such compositions is well-illustrated in the rapidly growing use of latices in the production of Water base paints. Hitherto however, no suitable organosiloxane -latices -have been -ava-11 ble This -invention makes possible the preparation of such materials on a commercial scale. It is the primary object of this invention to provide a novel process; for polymerising organopolysiloxanes Another object is to provide superior organopolysiloxane emulsions. Another object is to provide emulsified polysiloxanes of sufficiently high molecular weight to serve as protective coating Another object is to provide a process of more rapidly polymerising organosiloxanes with an acid catalyst. Another object is to, provide a more rapid process for the preparation of hydroxyl endblocked diorganosiloxane liquids of controlled molecular size. In accordance with this invention the poly. merisation of an organopolysiloxane is carried out while the siloxane is dispersed in an aqueous media The polymerisation is effected by contacting the dispersed siloxane with ,,, catalyst which is a strong mineral acid or a strong alkali 50 In carrying out the process of this invention the siloxane may be first dispersed in the water preferably with the use of an emulsifying agent and the catalyst then added and the emulsion allowed to stand with or without agitation at 55 the desired temperature until the siloxane has; reached the desired state of molecular aggregation Alternatively, the catalyst may be added to the siloxane prior to dispersion or simultaneously with dispersion In the 60 preferred procedure an emulsifying agent is dispersed in the siloxane and the mixture is then added with agitation to water to give the desired emulsion The catalyst is then added and polymerisation is allowed to proceed 65 Polymerisation of the siloxanes proceeds satisfactorily at room temperature but may be carried out at any desired temperature Preferably, of course, this should be below the boiling point of water although if desired, tein 70 peratures above 1000 C can' be employed if the polymerisation is carried out in a closed system The preferred temperature range is from 25 to 800 C. Thle time of polymerisation is not critical but 75 will vary depending upon the speed of the reaction and the viscosity desired in the result ing siloxane The time may also, be regulated by the particle size desired in the finished -emulsion It has been found that as the poly 83 merisation proceeds the viscosity of the siloxane will increase and the size of thelemulsion droplets decreases A combination of these two processes is believed to result in the extremely stable emulsions obtained by the -process of 85 this invention.

The concentration of the siloxane with res, pect to the water is not critical All that is required is that dispersion be a siloxane-inwater emulsion Thus so long as there is 90 enough water to give a continuous aqueous phase the polymerisation will proceed in i accordance with this invention Polymerisai tions can be carried out at siloxane concentra1 tions of 1 % by weight or less 95 L When polymerisation is complete the sil785,174 oxane may be recovered from the emulsion by breaking it in any desired fashion such as by the addition of salts such as sodium chloride or by evaporation of the water. The organosiloxanes are of the general formula R Si O 4 _, in which each R is a mono2 valent hydrocarbon radical or a halogenated monovalent hydrocarbon radical, if desired some of the R radicals being replaced by hydrogen atoms, and in which N has an average value from 1 to less than 3 Thus it can be seen that the siloxanes employable range from resinous materials having an average of IR group per silicon up to liquid end-blocked polymers having an average of more than 2 R groups per silicon The viscosity of the starting siloxane is not critical If the viscosity is too high for adequate disersion of the siloxane, a small amount of solvent may be employed which may subsequently be removed if desired, before polymerisation is begun It should be understood that the process of this invention applies equally well to the preparation of homopolymeric siloxanes and to the preparation of co-polymeric siloxanes Thus for example one may polymerise an organosiloxane of the general formula R 2 Si O such as dimethylsiloxane or one may co-polymerise mixtures of siloxanes of the formulae R Si QO 1; 5 R 25 i O and R Si O O,. For the purpose of this invention the organopolysiloxanes can be substituted by monovalent hydrocarbon radicals such as alkyl radicals such as methyl, ethyl, and octadecyl; alkenyl radicals such as vinyl, alklyl and hexenyl; cycloaliphatic radicals such -as cyclohexyl and -cyclohexenyl; aryl hydrocarbon radicals such as phenyl, tolyl and xenyl; and alkaryl hydrocarbon radicals such as benzyl; halogenated monovalent hydrocarbon radicals such as chlorophenyl,,wca-trifluorotolyl, trifluorovinyl, trifluorochlorocyclobutyl and tetrabromo xenyl The R groups on the siloxane can also be hydrogen although preferably there should not be more than 1 hydrogen atom per silicon. The catalysts which are operative in the process of this invention are strong mineral acids such-as hydrochloric, hydrobromic, hydroiodic, sulphuric, nitric, and phosphoric acids and strong alkaline catalysts such as alkali metal hydroxides such as sodium hydroxide, caesium hydroxide and lithium hydroxide andquaternar-y ammonium hydfoxidqs of the general formula RINOH In the latter each R' group can be any a Lkyl hydrocarbon radical such as methyl, ethyl, ocetadecyl, or any

aralkyl radical such as benzyl and phenyl-ethyl, or hydroxyalkyl radical such as hydroxyethyl, hydroxypropyl or hydroxybutyl These acid and alkaline catalysts are characterised by their ability to rearrange siloxane bonds. The catalyst may be emloyed in any desired amount and the particular amount will vary depending upon the nature of the catalyst For example, alkaline catalysts are preferably 65 employed in relatively low concentrations such as from 1 alkali molecule per 100 silicon atoms to 1 alkali molecule per 50,000 silicon atoms. On the other hand, acid catalysts are generally employed in higher concentrations, i e the 70 acid concentration in the aqueous phase of the emulsion may range from 15 to 80 % by weight. The preferred acid catalyst is hydrochloric acid The preferred alkaline catalysts are 75 quaternary ammonium hydroxides having at least 1 alkyl radical containing at least 12 carbon atoms attached to the nitrogen These hydroxides are preferred because they perform both as emulsifying agents and as polymerisa 80 tion catalyst for the silexane Their superior performance over other alkaline catalysts is presumably due to a higher degree of solubility in the dispersed siloxane than is obtained with other alkaline materials such as the alkali metal 85 hydroxide or quaternary ammonium hydroxides having lower alkyl or aralkyl radicals -altached to the nitrogen The preferred quaternary ammonium hydroxides may be employed either as the hydroxide, per se, or 90 in the form of a salt such as for example the quaternary ammonium chlorides, nitrates, sulphates and acetates In case the salts are employed, excellent emulsions are formed but polymerisation is not obtained unless an acid 95 catalyst is added or the emulsion is rendered alkaline by the addition of some alkaline material such as ammonia, sodium carbonate, or organic amines When the emulsion is rendered alkaline some of the quaternary ammo 100 nium, hydroxide is generated in situ and catalyses the polymerisation of the siloxane. Specific examples of the preferred alkaline catalysts are octadecyltrimethyl ammonium hydroxide, didodecyldiethyl ammonium hyd 105 roxide, tetradodecyl ammonium hydroxide, tritetradecylmethyl ammonium hydroxide and hexadecyloctadecyldimethyl ammoniumnhydroxide. As stated above the dispersion of the sil 110 onxane may be carried out in any desired manner This is best accomplished, by the use of a dispersing agent which can be of the cationic, anionic or nonionic type The specific type of emulsifying agent chosen will 115 depend somewhat on the catalyst employed. For example, it is preferably not to employ an acid catalyst in conjunction with anionic emulsifying agents In general it has been found that the cationic type of dispersing agent 120 is the best for

alkaline polymerisation The nonionic type of emulsifying agent being about equally suitable with either alkaline or acid catalysts The dispersing agent can be any cationic 125 emulsifying agent such as aliphatic fatty amines and their derivatives such as dodecylamine acetate, octadecylamine acetate and acetates of the amines of tallow fatty acids: homo-785,174 logues of aromatic amines of tallow fatty acids; homologues of aromatic amines having fatty chains such as dodecylanaline; fatty amides derived from aliphatic diamines such as undecylimidazoline; fatty amides derived, from disubstituted amines such as oleylaminodiethylamine; derivatives of ethylene diamine; quaternary ammonium compounds such as dioctadecyl-dimethyl ammonium, chloride, didodecyldimethyl ammonium chloride and dihexadecyldimethyl ammonium, chloride; amide derivatives of amino alcohols such as P 3-hyd& roxyethylstearylamide; amine salts of long chain fatty acids; quaternary ammonium bases derived from fatty amides of di-substituted diamines such as oleylbenzylaminoethylene diethylamine hydrochloride; quaternary ammonium bases of the benzimidazolines such as methylheptadecyl benzimidazole hydrobromide; basic compounds of pyridine and its derivatives such as cetylpyridinium chloride; sulphonium compounds such as octadecylsulphonium methyl sulphate; quaternary ammonium compounds of betaine such as betaine compounds of diethylamino acetic acid and octadecylchloromethyl ether; urethanes of ethylene diamine such as the condensation products of stearic acid and diethylene triamine; polyethylene diamines; and polypropanolpolyethanol amines. Suitable nonionic emulsifying agents are the saponines; condensation products of fatty acids with ethylene oxide such as dodecyl ether of -tetraethylene oxide; condensation products of ethylene oxide and sorbitan monolaurate; condensation products of ethylene oxide and sorbitan trioleate and condensation products of phenolic compounds having side chains with ethylene oxide such as condensation products of ethylene oxide with isododecylphenol and imine derivatives such as polymerised ethylene imine and N-octadecyl-N-N'-ethylene imide. Suitable anionic emulsifying agents are alkali metal sulphoricinates; sulphonated glyceryl esters of fatty acids such as sulphonated monoglycerides of coconut oil acids; salts of sulphonated monovalent alcohol esters such as sodium oleylisethionate; amides of amino sulphonic acids such as the sodium salt of oleyl methyl tauride; sulphonated products of fatty acid nitriles such as palmitonitrile sulphonate; sulphonates aromatic hydrocarbons such as sodium a-naphthalene monosulphonate; condensation products of naphthalene sulphonic acids with formaldehyde; sodium octahydroanthracene sulphonate and alkylarylsulphonates having 1 or several alkyl groups of 8 or less carbon atoms.

The emulsions prepared by the process of this invention are characterised by extreme stability and extremely fine particle size The dispersed particles of siloxane are so small that they cannot be resolved under an optical microscope The stability of the emulsions is exemplified by the fact that they stand for at least a year without separating and they can ben centrifuged 2000 r p m for 30 minutes without any sign of separation and can be diluted to any concentration without separation These emulsions can be rendered neutral 70 by proper neutralisation of the catalyst and if desired, the emulsion can be changed from a cationic to an anionic or nonionic systemor vice versa after polymerisation is complete or during polymerisation Thus, for example, if 75 polymerisation is to be carried out with an acid, it is best that a cationic or non-ionic emulsifying agent be employed However, it is sometimes desirable to employ anionic emulsifying agents since better wetting of certain 80 surfaces is thereby obtained This change can be effected with the emulsions of this invention without any deleterious effects as to particle size and stability by merely adding an anionic dispersion agent to the system 85 The emulsions of this iinvention may be employed for release agents or for coating compositions The process of this invention is particularly adaptable for the preparation of latex paints For example, the emulsion can be 90 mixed with the desired pigment or other fillers and then applied to a surface where the water will evaporate leaving a continuous coating. It should be understood that the utility of the process of this invention is not limited 95 to the production of emulsions but may also be employed to facilitate production of siloxane polymers which can be recovered by breaking the emulsion This is particularly true in the case of acid catalysed polymers since the speed 100 of reaction is greatly increased in the process of this invention over the speed obtained with heretofore known processes This is particularly true with low temperature polymerisation. The viscosity of the siloxanes shown in the 105 following examples refers to the viscosity of the siloxanes per se at 250 C and not to that of the emulsion The viscosity was determined by separating the siloxane from the emulsion and determining its viscosity by usual methods 110 The following examples illustrate the invention. EXAMPLE 1. 8 g of a mixture of 70 % by weight of diocetadecyldimethyl ammonium chloride and 115 % by weight of dihexadecyldimethyl ammonium chloride (said mixture being hereinafter referred, to as Arquad 2 HT the word " Arquad " being a Registered Trade Mark), were dissolved with warming in 283 g of octa 120 methylcyclotetrasiloxane having a viscosity of 2.3 cs The solution was then added with stirring to 243 g of water The

resulting emul sion was made alkaline by the addition of aqueous ammonia The emulsion was, heated 125 at 700 C for 10 hours whereupon the viscosity of the siloxane was 3000 cs The resulting emulsion was quite stable. EXAMPLE 2. Employing the process of Example 1, 30 g 130 o if ixed cyclic 6thylhnethy Isil 6 xanes having a the aqueous phase and 1 3 hours thereafter the viscosity of 5 3 cs,-1 g of Arquad 2 HT, and viscosity of the siloxane was over 1,000,000 -g of-water were emulsified and then mixed cs The resulting emulsion was quite stable. with 35 g of 28 % aqueous ammonia The alkaline emulsion was allowed to stand at EXAMPLE 8. room temperature whereupon the viscosity of A mixture of 142 g of cyclic dimethylsilthe siloxane gradually increased to 27 cs The oxane and 6 9 g of cyclic vinylmethylsiloxane emulsion -showed no sign of separation after having a viscosity of about 3 7 cs and 7 8 g. one year of the trimethylnonylether polyethylene glycol EXAMPLE 3 were mixed and added with agitation to 150 g. Employing the process of Example 1, an of 36 5 % hydrochloric acid The emulsion so emulsion of 30 5 % by weight of a mixture of formed was allowed to stand at room tempera7 5 mol % of cyclic phenylmethylsiloxanes and ture After 5 hours the viscosity of the co-poly92 5 mol % of cyclic dimethylsiloxane, having mer was 1420 cs The acid concentration in the a viscosity of about 4 5 cs, 1 % by weight of aqueous phase was then lowered to 30 % by Arquad 2 HT, 59 % by weight of water and -the addition of water and after 1 hour at room 9.5 % by weight of ammonia was prepared and temperature the viscosity was over was heated at 500 C for 5 days -After 2 days 1,000,000 r cs, the viscosity of -the siloxane -was 6000 cs and EXAMPLE 9. after 5 days the viscosity had risen to 22600 An emulsion was prepared in accordance -cs After 1 year the emulsion was centrifuged with the process of Example 8 from a mixture at 2000 r p m for 30 minutes No separation of 122 1 g of cyclic dimethylsiloxane, and 24 occured g of cyclic methyl hvdrogen siloxane having : f _ O EXAIMPLE 4 Employing the process of Example 1, an emulsion-was prepared from 30 g of mixed cyclic phenylmethylsilaxanes having a viscosity of less than 10 cs, 7 5 g of Arquad 2 HT, 70 g of water and 5 g of 28 % ammonium hydroxide; The emulsion was allowed to stand at -room temperature whereupon polymerisation of the phenylmethylsiloxanes to a higher viscosity took place EXAMPLE -5. 2 g of a mixture of about 70 % by weight of didodecyl-dimethyl ammonium chloride and about 30 % by weight of ditetradecyldimethyl ammonium chloride (said mixture being known as Arquad 2 C) was mixed with 30 g of octamethylcyclotetrasiloxane having a viscosity a

viscosity of about 3 3 cs, 8 g of the tri 85 methylnonyl ether of polyethylene glycol and g of 36 5 % hydrochloric acid After 24 hours' standing at room temperature the viscosity of the liquid was 358 cs The acid concentration was -then lowered to 32 % in the 90 aqueous phase and after 40 minutes the viscosity of the fluid had risen to 592 cs. EXAMPLE 10. A mixture of 50 g of cyclic dimethylsiloxane having a viscosity of about 3 3 -cs and 2 parts of the trimethylnonyl ether of polyethy-lene glycol was emulsified with 50 parts of 62 % sulphuric acid The emulsion stood at room temperature and after one day the viscosity of the siloxane had reached 1162 cs. 2 30 -cs and the -solution was poured into 70 EAMPLE 11. g of 15 % aqueous hydrochloric -acid The 40 g of a 55 % toluene solution of a resinous mixture was emulsified -by agitation and then siloxane having the composition 33 mol % of heated at 500 -C whereupon the viscosity of monophenylsiloxane, 32 5 mol % of monothe siloxane increased to 466 cs methylsiloxane, 27 mol % of phenylmethyl 105 siloxane and 7 5 mol % of diphenyl siloxane = EXAMPLE 6 the solution having a viscosity of less than 10 A mixture of 10 g of octamethylcyclotetra cs, was mixed with 2 g of Arquad 2 HT The siloxane having a viscosity of 2 3 cs and 1 g of mixture was then added with stirring to 60 Wg. octadecyltrimethyl ammonium chloride was of water 5 g of 28 % aqueous ammonia was 110 emulsified with 10 mil of 36 5 % hydrochloric then added to the emulsion After one day a acid and the emulsion was allowed to stand at substantial increase in the molecular weight of room temperature whereupon the viscosity the resin had occurred. increased -to 20000 cs ' EXAMPLE 12. : 2 g of a mixture of 70 % by weight of di 115 EXAMPLE 7 octadecyidimethyl ammonium hydroxide and A mixture of 150 g of octamethylcyclo 30 % by weight of dihexadecyl-dimethyl tetrasiloxane having a viscosity of 2 3 cs and ammonium hydroxide was added to 60 g of 7 5 g of the trimethylnonylether of polyethy cyclic dimethylsiloxane having a viscosity of lene glycol was emulsified with 60 g of 36 5 %i 3 7 cs -The mixture was poured into water 120 hydrochloric acid and allowed to stand at 250 and agitated to give an emulsion and the emulC After 4 hours the viscosity of the siloxane sion -was heated at 500 C. was 5600 cs The emulsion was diluted with The viscosity of the siloxane increased to atertogive an acid concentration of -18 % in f 16800 csc785,174 EXAMPLE 13. A mixture of 74 g of cyclic dimethylsiloxane having a viscosity of 3 7 cs 1 5 g.

of ammonium oleate was added to 75 g of water The mixture was agitated to give an emulsion and 2 2 g of potassium hydroxide were added The emulsion was heated in a closed vessel at 1250 C whereupon the viscosity of the siloxane increased to 1025 cs. Equivalent results were obtained when caesium hydroxide was employed as a catalyst. EXAMPLE 14. An emulsion containing 40 % by weight of cyclic dimethylsiloxane having a viscosity of 3 3 cs, 2 % by weight of sodium lauryl sulphate, 1 % by weight of Arquad 2 HT and 57 % by weight of water was prepared in the usual manner The siloxane in the emulsion was polymerised by employing a small amount of a tetramethyl ammonium hydroxide as a catalyst Equivalent results were obtained when sodium hydroxide was employed as the catalyst. EXAMPLE 15. An emulsion was prepared in the usual manner from 1050 g of cyclic dimethylsiloxane having a viscosity of 3 3 cs, 1579 g of water and 60 g of Arquad 2 HT 432 g of 28 % aqueous ammonia was then added to the emulsion and the product was polymerised by heating at 500 C until the viscosity reached 63300 cs The resulting emulsion was then agitated as 72 95 g of sodium laurate sulphate in 250 g of water were added The ammonia was then removed from the emulsion by bubbling air therethrough whereupon a neutral anionic very stable emulsion resulted This emulsion wets glass. EXAMPLE 16. A co-polymeric siloxane was obtained when a mixture of 90 mol % cyclic dimethylsiloxane and 10 mol % of:H 2 H Me I I I C-C Si O I C Ca F 2 F having a viscosity of less than 10 cs was emulsified and polymerised in accordance with the procedure of Example 8. EXAMPLE 17. Trimethyl end-blocked dimethylsiloxane liquids were obtained when a mixture of 99 mol %/Q of cyclic dimethylsiloxane and 1 mol. % of hexamethyldisiloxane having a viscosity of 2 2 cs were co-polymerised in accordance with the procedure of Example 1.


* GB785175 (A)

Description: GB785175 (A) ? 1957-10-23

Process for the production of elastic coatings

Description of GB785175 (A)

A high quality text as facsimile in your desired language may be available amongst the following family members:

DE1011548 (B) FR1140230 (A) DE1011548 (B) FR1140230 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 7859175 Date of Application and filing Complete Specification Jan 23, 1956. No 2194/56. Application made in Germany on Jan 24, 1955. Complete Specification Published Oct 23, 1957. Index at Acceptance:-Classes 2 ( 6), P 2 A, P 2 C( 8 B: 8 C: 9:17: 2 B), P 2 D( 1 A: B: 1 X: 2 A), P 2 K( 7: 8:9:10), P 2 P 1 (B:C:D:E 3:E 5:F), P 2 P( 2 A 3:2 A 4:4 A),-P 2 T 2 A, P 6 A, P 6 C( 8 B: 8 C: 9:17: 20 B), P 6 D( 1: 8), P 6 K( 7: 8:9), P 6 P 1 (B:C:D: E 3: ES: F), P 6 P( 2 A 3: 2 A 4: 4 A), P 6 T 2 A, P 7 A, P 7 C( 8 B: 8 C: 9: 17: 20 B), P 7 D( 2 A 1: 2 A 2 B: 3: 8), P 7 K( 2: 8: 9), P 7 P 1 (B: C: D: E 3: E 5: F), P 7 P( 2 A 3: 2 A 4: 4 A), P 7 T 2 A, -P 8 A, P 8 C( 8 B: 8 C:9: 17: 20 B), P 8 D( 2 A: 2 B 2: 3 A: 3 B: 8), P 8 K( 2: 7:8:9), P 8 P 1 (B: C: D: E 3: E 5: F), P 8 P( 2 A 3: 2 A 4: 4 A), P 8 T 2 A, P 9 A, P 9 C( 8 B: SC: 9: 17: 20 B), P 9 D( 1 B 1: 8), P 9 ( 2:

6:7: 8), P 9 PI(B: C:D: E 3: E 5: F), P 9 P( 2 A 3: 2 A 4: 4 A), P 9 T 2 A; and 95, B 4 X. International Classification: -B 05 CO 8 d, f. COMPLETE SPECIFICATION Process; for the Production of Elastic Coatings We, FARBENFABRIKEN BAYER AXTIEN action, which contain no free acid groups, 2) GESELLSCHAFT, of Leverkusen-Bayerwerk, other polymerisable ethylenically unsaturated Germany, a Body Corporate organised under organic compounds, which contain no free the laws of Germany, do hereby declare the acid groups, and 3) semi-esters of a-P 6-ethylene invention, for which we pray that a patent dicarboxylic acids with alcohols which contain 45 may be granted to us, and the method by at least 8 carbon atoms in aliphatic or cylowhich it is to be performed, to be particularly 7 aliphatic bond, or salts of these semi-esters. described in and by the following state Suitable polymerisable ethylenically unment:_ a o e saturated organic compounds with an elasticisThis invention relates: to elastic coatings Ming action ar, for example acrylic and, '50 and to a process for their production methacrylic acid esters of alcohols with at least Our Specification No 763,396 describes and 4 carbon atoms, for instance butyl alcohol, claims a process for the emulsification 'of an dodecyl alcohol, octadecyl alcohol, vinyl alkyl organic _liquid in water with the aid of an ethers, the alkyl radicals of which contain at emiulsifier, which comurises agitating an least 4 carbon atoms, vinyl isobutyl ether, 55 aqueous solution of an alkali metal hydroidie - vinyl butyl ether, compounds with conjugated withl a solution in a water-immun'scible organic double bonds, such as butadiene, its homoliquid of a co-polymer of at least ione poly logues and derivatives such as isoprene, 2,3merisable, water-insoluble vinyl compound -:dimethyl butadiene an'd /3-chloro-butadiene. and at least one polymerisable-acid co M'pounid Examples of polymerisable organic com 60 having 'the general formula R-CH-CX pounds which do not have ao elasticising action CO-OH, wherein X represents a hydrogen or are: tyr'ene, acryloitrile, methacrylonitrile, halogen atom or an alkyl group and R rep acrylic or methacrylic= ester s of alcohols -with resents a COOR' CONHR' or CONR'R 11 1 3 carbon atomss -1,-dichloroethylene, group, in wbhih R' andi Rn stands-f 6 o alkyl divimyl henzene 65 radicals containing inore thaif 8 cabon aiiris, -Suitable semiesters of a ethylene dicarthe ratio, of the vinyl compound'to the acid boxyi acids and alcohols with at least 8 carused in the piroduction of the co oym-er bonu atoms-in aliphatic or c cloaliphatic bond being such as to produce a T copolymer thie are for exampf 6 lte semi-esters of maleic acid alkali metal salts of Which are water-insoluble, and fuimaric

acid with aliphatic alcoh 6 ls, such 70 wheieby -during the agitation 'an alkali metal as for example octyl alcbhol, dodecyl alcoholl salt of the co-polymer is formed a'd acts as and oltadecyl ailcohol; Alcohols which have an emulsifier proved to be particularly suitable are cycleo In accordance with the present invrention it aliphatic alcohols with several ring systems and 'has been found that elastic coatings with gobd -akyl side chains, such as for example abietic 75 bonding' powers = can -be obtained from emul alcohol. sion 6 olmers which are produced by the It is preferable to' use 1) the polymerisable emulsion polymerisation, at a i H value higher unsaturated organic compounds with an than 7, of 1) 'polymerisable ethylenicall; un elasticising action in-amounts of 30 to 94 per saturated compounds -with -an -elasticising cent by weight; 2) the other polymerisable 80 lPrice 3 s 6 d l We Ce 4 S M 6 organic compounds in amounts of 70 to 5 per acrylonitrile and stirred for 30 minutes at 65 cent by weight and 3) the semi-esters or their room temperature with 1800 parts of water, salts in amounts of about 1 to 20 per cent by 150 parts of IN caustic soda solution, 1 2 parts weight, calculated on the total amount of the of triethanolamine, 2 4 parts of dodecyl merpolymerisable compounds It is, however, also captan and 550 parts of butadiene, possible to use other proportions: -i 3 7 parts of potassium persulphate 70 The polymerisation is preferably carried out are thereafter added and the temperature in aqueous medium andat a p H value of -from adjusted to 25 e C The p H value during poly8 to 10 Since the semi-esters mentioned above merisation is maintained at a value of from act as emulsifiers, it is generally unnecessary 8 to 10 The polymerisation is complete after to employ another emulsifier If another emul about 12 hours -A homogeneous stable emul 75 sifier is -used, however, the known emulsifiers, sion is formed, which after being spread, dries such as for example soaps or alkyl aryl sul as a completely transparent film with good -phonates, can be used for this purpose The bonding strength. polymerisation can be activated by free-radicalforming substances, for example peroxides, EXAMPLE 2. potassium persulphate and/or with redox sys 50 parts of the acid ester of maleic acid and 80 tems, by -which are to be understood the abietic alcohol are dissolved in 300 parts of combinations of oxygen-yielding and reducing styrene and 50 Parts of acrylonitrile and stirred, agents Suitable reducing agents for this for 30 minutes at room temperature with 1800 purpose are sulphinic acid sugar, ascorbic parts of water, 150 Darts of IN caustic soda acid, amines, salts of polyvalen t metals solution, 1 2 parts of triethanolamine, 2 4 85 and mercaptans Furthermore, it is post parts of dodecyl mercaptan and 550 parts of

sible for the thermiioplastic properties -of -the butadiene 3 7 parts of potassium persulphate copolymers to _be influenced according to are thereafter added and the temperature known liethpds by adding regulators to the -adjusted to 25 C The PH value during poly-polymerisation mixtures Stabilizefs such as -t erisation is maintained at a value of from 8 90 -for example -phenyl-1-naphthylamine, can be to 10 The polymerisation is complete after added to the polymer emulsion prinr towork about 24 hours A homogeneous stable emuling up X sion is formed, from which can be produced The polymerisation of the invention can be films which dry with a good bonding strength. carried out at a temperature of between 0 and 500 C preferably at -room-temperature EXAMPLE 3 95 Surface coatings produced from polymer -125 parts of the acid ester of maleic acid emulsions obtained in this manner are extra and dodecyl alcohol are dissolved in 688 parts ordinarily waterproof after drying and do not _of styrene and 125 Parts of acrylonitrile The lose their bonding strength when they are solution is stirred for 30 minutes at room temexposed to the action of water or steam Since -perature in an autoclave with 2300 parts of 10 C -their bonding power with metal surfaces is also -water, 250 parts of IN caustic soda solution, -for the manufacture of protective sedling layers zbutadiene 3 75 Darts of potassium persulphate -on packings Sealing rings for preserve jars are then added and the temperature raised to can also be produced in a simple manner by 300 C The -p, value during the polymerisation 105 -means of these polymer emulsions Owing to is maintained at 8 to 10 A homogeneous stable -the good bonding power of the coatings and -polymer emulsion is formed, which dries as a their excellent resistance to water, jars sealed r imly adhering coating. -with these rings can readily be subjected to 5,a sterilising process EXAMPLE 4. Various additions, such as pigments, dye 16500 Parts of water, 1500 parts of 110 -stuffs andc casein can be made to the polymer IN-Na OH, 12 parts of triethanolanine and -emulsions,c depending on the purpose for 24 varts-of n-dodecyl mercapitan are placed in :which they are to be used Vulcanising agents -a 40 litre autoclave equipped with stirrer and -such as zinc oxide and sulphur, as well as intensely stirred for 30 minutes, after addition _vulcanisation accelefators may be 7 added -of 7200 parts of butadiene with a solution of 115 X The surface coating produced from these 600 parts of the semi-ester of maleic acid and -polymer -emu Isions'can be dried at room, temr hydro-abidtic alcohol in 2100 p arts of acryloni-perature and, more rapidly at higher tempera trile and 2100 parts of styrene Thereupon 36 Iture, say up to 90 C =-'parts of potassium, persulphate dissolved in z The

invention is further illustrated by the little water are added and the temperature is 12 C following examples in which are parts are by -adjusted to 250 C The reaction is to be carried zweight;-' ' 7 ';out at a p H of 8 5 to 9 and the p H is if necesX -isary, adjusted The emulsion is polymerised :: X EXAMPLE 1 = unti it contains about 38 to 40 per cent of the parts of the acid ester of maleic acid and -copolvner thereupon it is stabiilsed with 120 125 abietic alcohol are dissolved in 350 parts of g of '2,6-di-tert -butyl-p-cresol and degasified. 785,175 785,175 A coating mass is prepared my homogeneously mixing: a) 333 parts of a polymer emulsion diluted so as to contain 30 per cent of solid substance, b) 80 parts of kieselguhr, 10 parts of kaolin, 1 part of colloidal sulphur, 0 5 part of zinc oxide, 1 part of zinc diethyl dithiocarbamate, 1 part of a stabiliser prepared by polymerisation of styrene in the presence of diphenylamine. The fillers set forth under b), before being added to the emulsion, are ground in a ball mill to form a dispersion with addition of 90 parts of an aqueous solution of a dispersing agent. The final mixture is applied by means of a nozzle to the rim of a tin lid to form a layer about 1 mm thick This layer is dried at 80 C An annular film is formed on the rim of the lid, which strongly adheres to the lid Upon folding the rim on to the tin, the film produces a tight sealing By boiling the sealed tin in hot water, the film is vulcanised and is thus given a good stability to ageing as well as a good resistance to oil and fat.


* GB785176 (A)

Description: GB785176 (A) ? 1957-10-23

Improvements in regenerative detector circuits



FR1146806 (A) US2921196 (A) FR1146806 (A) US2921196 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 785,176 @f f ipt l Date of Applcation and filing Complete Specification Feb 3, 1956. No 3476/56. Application made in United States of America on Feb 14,1955. Complete Specification Published Oct 23, 1957. Index at Acceptance:-Class 40 ( 6), T. International Classification:-1 o 3 f. COMPLETE SPECIFICATION Improvements in regenerative detector circuits We, GENERAL ELECTRIC COMPANY, a Corporation of the State of New York, United States of America, having its office at Schenectady 5, State of New York, 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 regenerative detector circuits and more particularly to circuits of this character utilizing transistor devices. In commercially known transistor devices, the power gain of a given transistor decreases rapidly with the increase of signal frequency. Due to this, operating characteristic, many r.f and i f amplifier stages may be required in order to obtain a high signal level The use of a large number of radio frequency and intermediate frequency stages may prove advantageous in providing an excellent signal to noise ratio and in providing good fidelity of the audio output signal However, for application in small, portable communication equipment, simplicity of circuitry and construction are paramount considerations For portable

receiver design, the required sensitivity must be obtained using a minimum number of amplifier stages. It is an object of the present invention to provide a new and improved regenerative detector circuit utilizing transistor devices. It is a further object of the present invention to provide a detector circuit which has a minimum number of amplifier stages yet provides excellent sensitivity. According to the invention there is provided a regenerative detector circuit comprising a junction-type transistor having base, emitter and collector electrodes means for applying an amplitude modulated input signal to said base electrode, an inductance in the emitter electrodes circuit, a tuned cirlPrice 3 s 6 d l cuit inductively coupled to said inductance, means for connecting said tuned circuit to the collector electrode, means for applying potential to the electrodes of said transistor and means so connected in the collector 50 electrode circuit as to produce an amplifier audio signal when said input signal is applied to said base electrode, The invention will, be more clearly understood from the following description taken 55 in connection with the accompanying drawing, in which the single figure shows a circuit embodying the invention. The embodiment of the invention illustrated in the drawing uses a PNP junction 60 type transistor 10 An input signal selected by resonant circuit 8 may be fed by inductive coupling to an inductance 9 which is connected to the base electrode 11 of transistor 10 Collector electrode 13 of transistor 65 is connected to a resonant circuit 30 whichincludes an inductance 16 and a variable capacitance 17 Resonant circuit 30 is regeneratively coupled to the emitter electrode 12 of transistor 10 by an inductance 14 The 70 windings of inductances 14 and 16 form a transformer 15 which has-variable coupling. An output transformer 18 is connected to the resonant circuit 30 The positive terminal of a source of potential 35 is connected to the 75 base electrode 11 of transistor 10, through a variable resistance 21 and inductance 9 _ Variable resistance 21 is shunted by a radio frequency by-pass capacitance 20 The negative terminal of source of potential 35 80 is connected through a variable resistance 23 to output transformer 18 The source of potential 35 and variable resistance 23 are shunted by an audio frequency by-pass capacitor 22 A radio frequency by-pass 85 capacitor 19 is connected between resonant -circuit 30 and inductance 14 Variable resistances 21 and 23 are used to supply the proper bias for PNP junction-type transistor When the proper biasing values are 90 Priee determined, these variable resistances may at radio frequencies diminishes the collector be replaced by resistances with fixed values curvature effect relative to the junction In operation, the disclosed circuit makes rectifying

effect which latter effect operates 70 use of the fact that there are amplified signal to impress on the base electrode a modulacurrents together with rectified signal cur tion frequency voltage amplified by the rents in -the output circuit of transistor 10 higher alpha existing in the transistor at By regeneratively coupling the output circuit modulation frequencies As noted, by assist to the input circuit of transistor 10, the r f ing in the predominance of the signals pro 75 voltage applied to the detector increases duced through rectification at the basewhich correspondingly increases the rectified emitter junction, the frequency dependence output signal, thus giving greater sensitivity of the transistor amplification factor is turned The present commercially known junction to advantage for the extension of the linear and point contact transistors have small detection range 80 power gain at high frequencies However, The amount of regeneration in the junction-type transistors have very good gain described circuit may be controlled by varyat audio frequencies The present invention ing the coupling between the windings of utilizes this property profitably by detecting transformer 15 When regeneration is carried amplitude modulated r f signals at a low as far as possible without producing oscilla 85 level, and then amplifying the audio signals tions, the resulting increase in amplitude is This is accomplished by regeneration great for extremely weak signals The It has been found that the minimum r f amount of regeneration should be controlled signal required for a transistor detector is on to ensure that the circuit will not start oscilthe order of 5 to 10 milli-volts An input lating, otherwise, the resulting output signal 90 signal inductively coupled from resonant may be extremely distorted or inaudible. circuit 8 by inductance 9 is applied to base By way of example only, experimental electrode 11 of transistor 10 This r f signal results have shown a junction transistor is comparatively small It appears amplified which has about 10 db power gain at a freat collector electrode 13 by transistor action, quency of approximately 1 megacycle can 95 and appears across resonance circuit 30 A function very well as a regenerative detector portion of this signal is fed back to emitter using the described circuit For a 1 megaelectrode 12 of transistor 10 by transformer cycle r f signal of 100 microvolts with 80 % Due to the positive feedback from modulation by a 400 cycle signal, an audio resonant circuit 30 to emitter electrode 12, frequency output of 3 millivolts was 100 the signal is again amplified The r f signal obtained It will be appreciated that other is amplified in this manner until it rises to a transistor devices and various signal frelevel of about 10 milli-volts, then the quencies suited for a particular application emitter-base junction of transistor 10 begins may be used The cited example is used detecting the r f signal At this time,

merely to illustrate an application of prim 105 changes in emitter current appear as changes ciples embodied in this invention. in collector current, and these changes It should be noted that a resonant circuit approximate the envelope of the incoming may be utilized to apply an incoming radio signal Thus, the signal -strength of an in frequency signal to the base electrode 11 of coming amplitude modulated r f signal is transistor 10 This would provide better 110 built up to a value to allow transistor detec receiver selectivity Also, output transformer tion and amplification of the detected signal 18 may be replaced with a set of headphones Since detection of the r f signal produces a (not shown), or a resistance in combination current which varies at an audio frequency with a coupling capacitor (not shown) It rate, and since the transistor provides excel will also appear obvious to those skilled in 115 lent gain in the audio frequency range, the the art, that an NPN junction-type transistor resulting sensitivity is greatly enhanced by may be used with the described circuit by utilizing transistor 10 in the detector circuit changing the polarities of source of potential The detection operation is aided by biasing 35.


* GB785177 (A)

Description: GB785177 (A) ? 1957-10-23

Improvements in or relating to methods of manufacturing indirectly heatedcathodes



BE545031 (A) DE1009315 (B) FR1140831 (A) NL100082 (C) US2860275 (A) BE545031 (A) DE1009315 (B) FR1140831 (A) NL100082 (C) US2860275 (A) less Translate this text into Tooltip



P A T E N T S P E C I F I CO 7 8 5, 1 7 7 PATENT SPECIFICATION -7-85,177 Date of Application ana filing Complete Specification Feb 6, 1956. No 3627/56. Application made in Netherlandson Feb 9, 1955. Complete Specification Published Oct 23, I 957. Index at Acceptance:-Classes 39 ( 1), D( 17 A 1: 17 AZB: 31); and 39 ( 3), H 2 E( 4 C: 11). International Classification:-Holj Ho 5 b. COMPLETE SPECIFICATION improvements in or relating to methods of manufacturing indirectly heated cathodes" We, PHILIPS ELECTRICAL INDUSTRIES LIMITED, of Spencer House, South Place, Finsbury, London, E C 2, a British Company, 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 methods of manufacturing indirectly heated cathodes for electric discharge tubes, more particularly cathodes of this kind in which the space' between the heater element and the cathode sleeve is filled by sintered insulating material. Frequently it is desirable that the space between the heater element and the sleeve of an indirectly heated cathode should be entirely filled with insulating material, which will be sintered As examples, mention may be made of cathodes having a high operating temperature or cathodes in which a very high degree of electric insulation between the heater element and the cathode is required. In addition, it is frequently desirable to avoid movements of the heater element relative to the cathode since such movements give rise to microphonic disturbances owing to variations in capacitance between the said parts.

It has, however, been found that it is very difficult to prevent the formation of cavities in the insulating material or between this material and the cathode sleeve during the process of filling the space and after sintering Sintering may be required in order to degas the insulating material and to prevent said material from falling out of -the cathode sleeve. The formation of such cavities is undesirable, particularly in view of the heat transfer between the heater and the cathode sleeve. Since the thermal conductivity is reduced by such cavities, no constant product is obtained, and different cathodes will exhibit varying temperatures since the cavity formation will differ from cathode to cathode. lPrice 3 s 6 d l Furthermore, due to cavity formation the heater is likely to become overheated locally so that the heater filament may become brittle. The principle object of the present inven 50 tion is to provide an improved method of manufacturing an indirectly heated cathode for an electric discharge tube-in which the. said disadvantages are mitigated. According to -the present invention a 55 method of manufacturing an indirectly heated cathode for an electric discharge tube, in which the space between the heater and the cathode sleeve is filled with sintered insulating material, is characterized in that 60 the insulating material is introduced into the said space by sedimentation from a suspension. This method provides the advantage of ensuring a partial separation between the 65 finer and coarser particles of the suspension. If the maximum height of fall, i e, the maximum distance the particles have to travel, is chosen sufficiently large, the coarser particles become located substantially at the 70 bottom and the finer particles substantially at the top of the cathode sleeve. In a preferred method in accordance with the invention, the maximum distance the particles have to travel is at least twice the 75 length of the space required to be filled. When the cathode sleeve is closed at one end, the greater part of the coarser particles become consequently located in the proximity of the closed end, whilst the greater 80 part of the finer particles become located in the proximity of the open end The coarser particles are only slightly sintered and consequently shrink only slightly, whilst the finer particles subsequent to sintering exhibit a 85 great mechanical strength and satisfactorily seal the open end The coarser particles produce a porous mass having some resiliency so that the formation of cavities by shrinking is avoided or reduced 90 / ii 11 1 i A maximum height of fall of from 2 to 3 times the length of the

space to be filled has proved advantageous, particularly when sedimentation is accelerated by the use of a centrifuge. In order that the invention may readily be put into practice, one embodiment will now be described with reference to the accompanying drawing, in which: Figure 1 shows a holder for the cathode sleeve and the suspension during sedimentation, and Figure 2 shows a centrifuge provided with such holders, whilst Figure 3 is a sectional view of a cathode after sedimentation and sintering. In Figure 1, reference numeral 1 denotes the emissive part of the cathode, which cathode in the case shown is a dispenser cathode, reference numeral 2 denotes the cathode sleeve in which the emissive part 1 is secured and 3 denotes the heater arranged in the cathode sleeve 2 The cathode sleeve 2 has a depression 4 formed in its periphery. The assembly comprising the emissive part 1, the sleeve 2 and the heater 3 is introduced into a metal holder 5 until the depression 4 abuts with the bottom of the holder 5 Said holder 5 has a cavity 9 formed in it which is provided with a tapering part which registers with a second cavity in the holder 5 within which second cavity the cathode sleeve fits The holder 5 is arranged together with the cathode assembly in an aperture 7 of a second holder 6 which may, for example, be made of synthetic resin The cavity 7 has a narrowed portion 8 in its bottom in which the emissive part 1 and depression 4 are accommodated A suspension of the insulating material to be provided in the cathode sleeve is now introduced into the sleeve 2 and space 9 Preferably use is made of ground and purified A 123, 1 kg of ground A 1203 being suspended in 1 litre of ethyl alcohol The size of the particles is preferably from 1 to 15 microns The height of the space-9 is greater than but less than twice the length of the cathode sleeve 2 The coarser particles of the suspension settle first and consequently come to rest substantially at the bottom in the proximity of the closed end of the cathode sleeve, the mean size of the particles decreasing in the direction from bottom to top When the solid substance is deposited, the liquid is decanted or evaporated and the holder 5 is taken from the holder 6 and heated until sintering of the insulating material occurs In the cathode finally produced which is shown in Figure 3, the filling of the lower end of the cathode sleeve consists substantially of coarser particles 12 (from 10 to 15 microns) whilst the -percentage of finer particles 13 (approximately 1 micron) gradually increases towards the upper end 65 The sedimentation can be considerably accelerated with the aid of a centrifuge, as is shown in Figure 2 The holder 6 can be suspended from an annular member 11 which is supported from arms 10 of a centri-7 fuge 'With a maximum height of

fall of from 2 to 3 times the length of the cathode, substantially complete sedimentation is produced after a period of from 5 to 10 minutes at a speed of 3000 revolutions per minute 75 and with a distance between the cathodes and the axis of rotation of approximately 10 to 15 cms, the solid substance filling the cathode envelope to the level shown by a broken line 14 in Figure 1 80 The sintering of the A 1203 is effected by heating, for two hours at 1000 MC and subsequently for 15 minutes at 1600 C It was found that substantially no cavities were formed either during filling or during sinter 85 ing It is necessary that the suspension contains particles of different sizes so that preferably ground insulating material is used as initial material. Although one embodiment of a cathode 90 has been described, that is to say a so-called dispenser cathode, the method according to the invention can also be used for the manufacture of tubular cathodes.


4766 4770.output

Law