5686 5690.output

* GB786094 (A)

Description: GB786094 (A) ? 1957-11-13

Phosphate compositions, their production and use

Description of GB786094 (A)

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up-to-date or fit for specific purposes.

PATENT SPECIFICATION

786,094 Date of Application and filing Complete Specification: April

18, 1955.

No 11075155.

Application made in United States of America on April 16 1954.

Complete Specification Published: Nov 13, 1957.

Index at acceptance -Classes 1 ( 3), A 1 (D 37: G 1 D 37:050 D 37);

and 919 D 2 (F:H:S).

International Classifcation:-CO 1 b, C 11 d.

COMPLETE SPECIFICATION

Phosphate Compositions, their Production and Use WC, MONSANTO CHEMICAL

COMPANY, a Corporation organized under the Laws of the State of

Delaware, United States of America, of 1700 South Second Street, City

of St Louis, State of Missouri, 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 alkali metal phosphate compositions and more

specifically to alkali metal tripolyphosphate and pyrophosphate

compositions which have a relatively low rate of precipitation or

crystallization from aqueous solution The invention also relates to

methods for producing the aforementioned phosphate compositions.

The invention also relates to the control of the rate of precipitation

or crystallization of such phosphates from aqueous solutions and is

particularly useful in connection with the manufacture of detergent

compositions by spray drying techniques.

Many detergent compositions, and especially those of the dry granular

type, such as those intended for home laundry use, are mafde up from a

plurality of components including a so-called "active" ingredient,

such as an alkali metal salt of a sulphonated alkylated aromatic

hydrocarbon or a condensation product of ethylene oxide with a long

chain alkyl alcohol or mercaptan, a predominant proportion of a

so-called "builder" such as sodium tripolyphosphate or tetrasodium

pyrophosphate, and a small amount of a corrosion inhibitor such as an

inorganic silicate, e g, sodium metasilicate.

One of the problems in formulating a satisfactory and commercially

useful granular mixture of several dry ingredients is to obtain a

satisfactorily uniform distribution of each of the separate

ingredients throughout the bulk of the mixture: failure to obtain this

will increase the probability that lPrice 3/61 small portions

withdrawn from the bulk of the mixture will have a composition

substantially different from the overall composition of the total bulk

Another problem in the formulation of such mixtures is to obtain a 50

satisfactorily uniform particle size distribution of the ingredients:

failure to obtain this will give rise to an automatic classification

process whereby the coarse and fine particles will tend to separate

from each other during 55 the transportation and handling of the

packaged or bulk solids.

One way in which the aforementioned difficulties are overcome, or at

least minimized, is by spray drying In such a pro 60 cess a slurry of

the solids in water is broken up into relatively uniformly sized

droplets by atomizing the slurry The droplets are then passed into or

through a heated zone wherein the water is evaporated from each 65 of

the droplets, leaving discrete dry granular particles or agglomerates

By proper control of the conditions under which the spray drying is

carried out, it is possible to obtain a reasonably uniform

distribution of particle 70 sizes, with each of the individual

particles containing approximately the same proportions of the various

components.

One of the factors which is particularly important in the control of a

spray drying 75 process is that of the viscosity, or consistency, of

the slurry which is to be atomized.

If the slurry is too thick or viscous, proper atomization thereof is

very, difficult In such a case the fluidity of the slurry can be 80

increased by increasing the amount of water in the slurry, but an

increase therein is undesirable since a large quantity of slurry must

be handled, and a larger quantity of water must be evaporated, for a

given output 85 of detergent composition Thus, it is very advantageous

to have the solid content of the slurry as high as possible while

still maintaining the required degree of fluidity for adequate

atomization of the slurry 90 C",; 786,094 As indicated above, sodium

tripolyphosphate and/or tetrasodium pyrophosphate are often used as

predominant components of granular detergent compositions prepared by

spray drying processes The commercial tripolyphosphate and

pyrophosphate utilized in such processes are usually in anhydrous form

When these anhydrous phosphates are made into an aqueous slurry, there

is a marked tendency for the slurry to increase rapidly in

consistency, and the slurry may be transformed into a completely

non-fluid mass This increase in viscosity or loss of fluidity is at

least partially caused by the is reduction in the free water content

of the slurry because of the hydration of the anhydrous phosphates and

may also be accentuated by the manner in which crystal growth of the

hydrates occurs As a consequence thereof, in order to maintain the

slurry in a satisfactory fluid state, it is necessary either to

increase the amount of water in the slurry or to find a way to prevent

or delay the precipitation or crystallization of the hydrates of these

phosphates.

Accordingly, objects of the present invention are to decrease the rate

of crystallization of certain phosphates from aqueous solutions

thereof, to provide a novel phosphate composition which is

particularly useful in the formation of high fluidity slurries

suitable for spray drying operations and to provide suitable methods

for making such phosphate compositions An additional object is to

provide a method for forming slurries of phosphates which are highly

suitable for spray drying processes.

According to the present invention there is provided a phosphate

composition comprising an anhydrous alkali metal phosphate having a

molar ration M 20/P 20 O, in which M is an alkali metal, or from 5/3

to 2 and a water-soluble linear polymeric phosphate having more than

three phosphorus atoms in its linear chain, the proportion of the

latter not exceeding 10 % of the total dry weight of the mixed

phosphates.

It has also been found that a very suitable phosphate composition can

be prepared by intimately admixing a comminuted watersoluble linear

polymeric phosphate of the above kind with a granular or powdered

anhydrous alkali metal phosphate, the proportion of the former not

exceeding 10 % 1, of the total dry weight of the mixed phosphates It

has also been found that such phosphate compositions are particularly

useful in the preparation of detergent slurries suitable for spray

drying to forn granular detergent compositions.

Typical of the linear polymeric phosphates suitable for use in the

various aspects of the present invention are the sodium phosphate

glasses, i e, the amorphous compositions having Na 2 OIP RO molar

ratios between 1 and 1 67 As has been pointed out in the literature

(see, for example, Van Wazer, Journal of the American Chemical

Society, volume 72, pp 644-647 and 647-655 ( 1950)), these phosphate

glasses are mixtures of 70 water-soluble, straight-chain, polymeric

materials having a chain consisting of alternating atoms of oxygen and

phosphorus.

These mixtures of linear polymeric phosphates can be characterized in

terms of an 75 average chain length, h The term "chain length", as

applied to these straight chain polymeric phosphates, refers to the

number of phosphorus atoms in the straight chain polymer 80 It is also

pointed out by Van Wazer that the average chain length of the mixture

of polymers in ia sodium phosphate glass is primarily a function of

the ratio of Na 2 O/P 20, in the melt from which the glass 85 was

formed The predominant polymer in such a mixture has a chain length

equal to the whole number most nearly approaching the value of the

average chain length The proportions of the other chain length poly-90

mers in the mixture become progressively smaller as the chain length

increases or decreases from the average chain length.

The average chain length of the glasses becomes increasingly greater

as the ratio of 95 Na O/P,O decreases ranging from a chain length of

three when the Na,OIP O ratio equals 5/3 to a chain length of several

thousands as the ratio of Na,O/P DO, approaches unity 100 As

previously indicated, the linear polymers suitable for use according

to the present invention are those having a chain length greater than

3 As the len Oth of the chain increases, the polymers become more

effec 105 tive for the purposes of the present invention Thus,

polymers having a chain length of 4 aremoreeffectivethan those having

chain lengths of less than 4 Likewise, polymers having a chain length

of 5 are more effective 110 than those having a chain length of 4 and

so on A preferred class of linear polymeric phosphates are those

having an average chain length greater than 10 While the effectiveness

increases as the chain length 115 increases, the rate of increase of

effectiveness with respect to increase in chain leneth decreases as

the chain length increases.

Examples of particularly desirable linear polymeric phosphates are the

commercially 120 available sodium phosphate glasses having molar

ratios of Na,OIP 1 RO, of substantially 1.1, substantially 1 4 and

substantially 1 55.

We have stressed the importance of sodium phosphate glasses in the

practice of 125 the present invention because they are very well known

and more widely available than some of the other sources of linear

polymeric phosphate ions However, it should be understood that any

material which can 130 786,094 supply the polymeric phosphate ion is a

suitable source Examples of other suitable materials are Kurrol's salt

(a water-soluble, crystalline linear polymeric potassium

metaphosphate), lithium phosphates having a molar ratio of Li 2 O/P O,

between 1 and 13, linear polymeric ammonium phosphates formed either

by replacing alkali metal ions of polymeric phosphates with ammonium

ions or by reaction of ammonia and phosphorus pentoxide (with or

without water) Also satisfactory are the acids corresponding to the

foregoing salts In order to affect the rate of crystallization of the

tripoly and pyrophosphates, it is necessary that the linear polymeric

phosphate ions be in solutioh Consequently, any salts which are used

as a source of such ions must be soluble in the tripoly or

pyrophosphate solution, at least to the extent of the minimum

effective concentration of the ion.

As indicated above, the effectiveness of the linear polymeric

phosphates increases with increasing chain length of the phosphates

When these linear polymeric phosphates are utilized with

tripolyphosphates, the effectiveness also varies somewhat with the

crystalline form of the tripolyphosphate.

As is well known, sodium tripolyphosphate exists in two different

crystalline formsone known as the high temperature form (or Form V),

and the other known as the low temperature form (or Form II) A

preferred embodiment of the present invention is the use of the

above-described polymeric phosphates with sodium tripolyphosphate-II,

or with the mixtures of Form I and Form II containing more than 75 %

by weight of the Form II material Best results are obtained when

using;mixdtures containing less than % by weight of Form I, or even

less than % by weight of Form I.

Because of -the marked change in effectiveness of the polymeric

phosphates with respect to both the chain length of the polymers and

the crystalline form of the phosphates to which the polymers are

added, the minimum effective concentration of the polymeric phosphates

will vary over a rather wide range In general, at least 0 01 % by

weight (based upon the total dry weight of phosphates present), and

preferably at least 0.1 % by weight, should be utilized In extreme

cases, such as when using the short chain polymers in tripolyphosphate

mixtures containing relatively large proportions of the Form I

modification, as much as 1 % by weight or more of the polymeric

phosphate may be required More than 10 % will not be required, and

under most circumstances %O will be more than adequate.

As indicated above, a preferred embodiment of the present invention is

the preparation of the alkali metal tripolyphosphate or pyrophosphate

compositions into which the water-soluble linear polymeric phosphates

have already been incorporated One of the simplest ways to prepare

such a composition is by fine grinding or otherwise comminuting the

polymeric phosphate and intimately 70 intermixing it with the granular

or powdered alkali metal tripolyphosphate or pyrophosphate in the

requisite proportions.

Another way to form such a composition with the polymeric phosphate

intimately 75 and uniformly distributed throughout the bulk of the

alkali metal tripolyphosphate or pyrophosphate is to form a solution

of the polymeric phosphate in a volatile solvent, such as water or an

alcohol-water mixture,80 and then to spray the solution on to or into

a heated bed of the other phosphate The solvent is evaporated 'from

the bed, thereby precipitating the polymeric phosphate within the bed

of tripoly or pyrophosphate It is 85 particularly advantageous to

maintain the temperature of the bed of phosphate above the boiling

point of the solvent in which the polymeric phosphate is dissolved In

this way, the solvent is evaporated very 90 quickly upon contact with

the phosphate bed, and there is less tendency for the solvent to

dissolve any of the tripoly or nyrophosphate and cause clumping or

agglomerating.

Another way of preparing suitable phos 95 phate compositions

containing small amounts of linearly polymeric phosphates is by

exposing the alkali metal 'tripolyphosphate to an elevated temperature

for a relatively short period of time in order to fuse 100 a small

amount of the material on the surface of the tripolyphosphate

particles The fusion of tripolyphosphate results in the formation of

solid pyrophosphate and molten linearly polymeric phosphates having

105 an average chain length somewhat above 3.

While equilibrium cooling of the fused tripolyphosphate would result

in the reconversion of the pyrophosphate and linear polymers to

tripolyphosphate, a relatively 110 rapid cooling will trap the linear

polymeric materials in a non-equilibrium glassy state, thus giving the

desired tripolyphosphate composition containing a small amount of the

linear polymeric phosphate of chain 115 length longer than 3.

The phosphate compositions into which the linear polymeric phosphates

have been incorporated are utilized in the preparation of crutcher

mixes (or slurries) for spray 120 drying in substantially the same

general manner that the phosphate builders have been utilized in the

past However, a higher concentration of solids can be utilized in

slurries of the present phosphate composi 125 tions without increasing

the viscosity of the slurry, or alternatively, the viscosity of the

slurry can be markedly decreased without decreasing the concentration

of solids in the slurry 130 786,094 As an alternative to incorporating

the polymeric additives into the slurry as an integral component of a

phosphate builder composition, the additives can be incorporated into

the aqueous slurries independently of the phosphate "builder"

addition.

If added independently, however, the linear polymeric phosphates

should be added to the slurry prior to, or at least at substantially

the same time as, the phosphate builder is added If added much later,

substantial precipitation and crystallization of the hydrated

phosphate will have taken place before the linear polymeric material

has an opportunity to delay such crystallization.

The term "linear" as us-ed herein with respect to the polymeric

phosphates, includes branched as well as "normal" chain phosphate

polymers, but excludes the cyclic phosphates such as the

trimetaphosphates.

The ammonium polyphosphates, and especially those in which oxygen

atoms have been replaced by imido nitrogen atoms, are examples of

linear polyphosphates believed to have branched chains.

The following examples illustrate the nature of the invention and the

manner in which it may be performed.

EXAMPLE 1

Fifty grams of 95 % glycerine and 50 g.

of powdered sodium tripolyphosphate ( 2.4 o by weight of Form I, the

remainder Form II) were thoroughly intermixed in a ml tall beaker

Twenty-five millilitres of water was then added to the mixture and vi

35 orously stirredforabout 2 minutes Theresulting mixture was then

allowed to stand for about minutes After this time the beaker was

inverted, but the consistency of the mixture had increased to such an

extent that only 40 a few drops of liquid ran out of the beaker.

A parallel test was carried out in the same manner, except that 0 5 g

of a glassy sodium polyphosphate having an average chain length of

substantially 5 5 was dissolved in 45 ml of water prior to inixina

with the glycerine-sodium tripolvphosphate mixture.

In this latter case, the enti-re slurry was readily poured from the

beaker after 30 minutes standing 50 EXAMPLE 2

The procedure of Example 1 was repeated.

except that various water-soluble linearly polymeric sodium phosphates

in finely 55 divided form were physically admixed with the sodium

tripolyphosnhate prior to incorporation into the glycerine The results

of these tests are sumnmarized in the following table: 60

SODIUM PHOSPHATE GLASS Average Concentration chain inr wt% length (ii)

0 0.4 5 5 0.5 5 5 0.75 5 5 0.1 15 5 0.4 155 1.0 15 5 0.02 112 0.1 112

EXAMPLE 3

The procedure of Example 2 was repeated, except that the water-soluble

linearly polymeric phosphate used was a crystalline potassium

polyphosphate having an average chain length of about 630 This

polyphosphate, commonly known as Kurrol's salt, was utilized in a

concentration of substantially 0.1 % by weight, based upon the sodium

tripolyphosphate After the 30 minutes standing period, most of the

slurry could be readily poured from the beaker-only about 0 75 inch of

solids remaining in the bottom of the beaker.

EXAMPLE 4

The procedure of Example 2 was repeated, RESULTS OF TEST Slurry

remained in beaker after inversion 65 Very small proportion of solids

remained after inversion Beaker completely emptied after inversion

Beaker completely emptied after inversion About 0 625 " of solids

remained in bot 70 tom of beaker after inversion About 0 25 ' of

solids remained in bottom of beaker after inversion Beaker completely

emptied after inversion About 0 75 " of solids remained in bottom 75

of beaker after inversion Beaker completely emptied after inversion

except that the water-soluble linear polymeric phosphate was an

ammonium poly 95 phosphate of the type described by Van Wazer in

"Encyclopedia of Chemical Technology", Vol X ( 1953) pages 419-20 The

specific ammonium polyphosphates used were reaction products of

ammonia, phos 100 phorus pentoxide, and water in the respective molar

proportions of (A) 2 02/1 00/1 29 and (B) 2 91/1 00/0 49 Sample A had

an average chain length of substantially twelve phosphorous atoms and

a water-solubility of 105 about 40 % by weight Sample B had an average

chain length of substantially eight phosphorus atoms and a water

solubilitv of about 60 %h by weight (The chain lengths 786,094 were

determined by the well-known endgroup titration method) The results

obtained by mixing various concentrations of these Composition (A) (A)

(A) (A) (B) (B) ammonium polyphosphates with sodium tripolyphosphates

are summarized in the fob S lowing table: AMMONIUM POLYPHOSPHATE GLASS

Concentration, in wt % RESULTS OF TEST None Slurry remained in beaker

after inversion 0.01 About 1 " of solids remained in bottom of beaker

after inversion 0 02 About 0 5 " of solids remained in bottom of

beaker after inversion 0 1 About 0 125 " of solids remained in bottom

of beaker after inversion 0.2 Beaker completely emptied after

inversion 0 2 Slurry remained in beaker after inversion 0 5 About 0

125 " of solids remaining in bottom of beaker after inversion EXAMPLE

5

The procedure of Example 2 was repeated except that 'the water-soluble

linear polymeric phosphate was formed upon the surfaces of the sodium

tripolyphosphate particles by briefly passing a flame over the surface

of a mass of tripolyphosphate After mixing and allowing to stand as

described in the foregoing examples, the slurry formed from the

flame-treated tripolyphosphate was readily poured from the beaker,

whereas the slurry prepared from an identical tripolyphosphate sample

without flame treatment had increased in viscosity to such an extent

that none of the slurry could be poured from the beaker.

EXAMPLE 6

The procedure of Example 2 was repeated except that tetrasodium

pyrophosphate was substituted for the sodium tripolyphosphate.

As in the cases where sodium tripolyphospliate was used, the slurry

prepared from tetrasodium pyrophosphate without any water-soluble

linear polymeric phosphates became so thick that it could not be

poured from the beaker However, when either 5 %.

by weight of a water-soluble linear polymeric sodium phosphate having

an average chain length of 5 5, or 0 5 % by weight of a watersoluble

linear polymeric sodium phosphate having an average chain length of 15

5 was added to the tetrasodium pyrophosphate, the resulting slurry

retained sufficient fluidity to be poured easily from the beaker.

EXAMPLE 7

A solution of sodium tripolyphosphate super-saturated with respect to

sodium tripolyphosphate hexahydrate was prepared by adding 340 g of

anhydrous sodium tripolyphosphate (about 2 5 % by weight of Form I) to

1000 ml of water The mixture was stirred for ten minutes, cooled to 25

C.

and filtered To a 100 ml portion of the filtrate, there were added (

1) 0 6 g of a sodium phosphate glass having an average chain length of

5 5 and ( 2) 10 g of recrystallized sodium tripolyphosphate

hexahydrate (The latter was added to provide a surface for

crystallization of the hexahydrate from the solution) The resulting

mixture was con 70 tinuously stirred while sodium tripolyphosphate

hexahydrate crystallized from the solution The rate of crystallization

was determined by periodically withdrawing samples of the supernatant

liquid and deter 75 mining the concentration of dissolved solids

therein Two other 100 ml portions of filtrate were treated in the same

manner except that sodium polyphosphate glasses of average chain

lengths 15 5 and 112 were 80 used A fourth portion of filtrate was

used as a control, being treated in the same manner as each of the

others except that no polyphosphate glass was added The results of the

foregoing tests are plotted in the ac 85 companying drawing in the

form of a graph of the amount of sodium tripolyphosphate hexahydrate

crystallized from the solution, as a function of time and average

chain length (fi) of the sodium polyphosphate 90 glasses added to the

solution From this graph it can be seen that the rate of

crystallization from solutions of the less highly condensed

phosphates, such as tetrasodium pyrophosphate and sodium tripolyphos

95 phate, is markedly decreased iby small amounts of water-soluble

linear polymeric phosphates, such as the sodium phosphate glasses.

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* 5.8.23.4; 93p

* GB786095 (A)

Description: GB786095 (A) ? 1957-11-13

Cushion plates for the closure members of grid-type valves


PATENT SPECHICATON

Inventors: -HENRY EDWARD MUCKLEY and JOHN WALDRON.

Date of filing Complete Specification: Nov 22, 1955.

Application Date: April 19, 1955 No 11229/55.


Index at Acceptance:-Class 135, VI 1.

International Classification:-FO 6 k.

COMPLETE SPECIFICATION.

Cushion Plates for the Closure Members of Grid-Type Valves.

We, BELLISS & MORCOM LIMITED, of Ledsam Street Works, in the City of

Birmingham 16, 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:-

The invention relates to a valve of the type for use in, for example,

air compressors, which comprises a grid-like seating having therein a

concentric arrangement of ports, a centrally supported closure member

consisting of a thin metal or other disc also having a like

arrangement of ports, a resilient or spring loaded cushion plate, and

a guard plate, the closure member and cushion plate being situated

between the seating and guard plate.

One of the disadvantages of a valve of the said type of conventional

construction is that during normal movements of the closure member

from and to its seating, friction occurs between the closure member

and a guide provided therefor, with consequent risk of stalling of the

closure member, or of wear which results in displacement of the

closure member relatively to its seating and consequent leakage of

fluid when the said member is in its closed position.

The object of the present invention is to provide an improved cushion

plate which enables the above mentioned disadvantage to be obviated in

a simple and reliable manner.

A cushion plate in accordance with the invention includes a pair of

deflectable arms which are inter-connected at their inner ends by a

ring adapted to fit closely a central aperture in the closure member,

and branchesextending from the arms, the branches having free ends

providing abutments for springs.

In the accompanying drawings:

Figure 1 is a plan, and Figure 2 a cross-section on the line 2 2 of

Figure 1 illustrating one form of cushion plate embodying the

invention.

Figure 3 is a plan of the closure member with which the cushion plate

shown in Figures 1 & 2 is adapted to co-operate.

Figure 4 is a cross sectional view of a valve provided with the

cushion plate shown in Figures 1 & 2.

Referring to Figures 1 and 2, the cushion plate there shown is made

from a thin disc of steel or other resilient metal Alternatively it

may be made from a resilient nonmetallic p Ihstic The disc is pierced

to form a narrow peripheral rim a, a diametrical bar b, a Dair of arms

c extending radially inwards from the rim and at right angles to the

bar, and a pair of segmental branches d extending laterally from each

of the arms and situated adjacent to the rim.

Alternatively, and particularly in discs of large diameter, the arm c

may be of bifurcated vee shape having its apex adjacent to the centre

of the disc The surface areas of the free ends of the branches d may

be enlarged as shown to provide adequate abutments e for the springs

to be hereinafter mentioned The plate may also be provided with other

segmental branches f, g.

At the centre and at one side of the cushion plate, there is secured

to the inner ends of the arms c by rivets h a ring i which can occupy

and closely fit a central aperture j in the closure member k (Figure

3) the ring serving to prevent lateral movement of the closure member

in its own plane relatively to the valve seating shown in Figure 4

Further the rim a of the 786,095 cushion plate is slit at two

positions m adjacent to the arms c to allow the arms and the branches

d to be deflected relatively to other parts of the plate.

s A valve construction for which the cushion plate above described is

required is shown in Figure 4 It comprises a flat seating n having

therein a number of concentric rings of segmental ports a At the

centre of the seating is attached a washer p of any convenient

thickness for supporting the bar b of the cushion plate, and around

this washer there is formed in the seating an annular groove q for

accommodating the ring i on the arms c The closure member k (as shown

in Figure 3) consists of a thin metal or plastic disc having therein a

plurality of rings of segmental ports situated opposite the lands

between the ports o in the seating, the closure member being held

against lateral movement by the ring i on the arms c of the cushion

plate, and being also held against rotational movement by, for

example, a peg (not shown) extending a 5 from a guard plate i through

holes r, S in the cushion plate and closure member respectively The

cushion plate is held against lateral and rotational movement by a peg

(not shown) extending from the seating through a hole t The guard

plate u is held in position by a nut or nuts v on a screw threaded

stem W extending from the seating through a hole in the bar and guard

plate.

In the underside of the guard plate are formed four equi-spaced

sockets x for helical springs y which bear on the ends e of the

branches d on the arms of the cushion plate By the action of the

springs the branches d and arms c are deflected out of the plane of

the other parts of the closure member and thereby caused to hold the

closure member in contact with the seating.

When during the action of the valve, the closure member is

intermittently moved off and on to its seating, no relative movement

occurs between the ring i and the closure member k Consequently no

friction occurs between the intercontacting parts of the closure

member and cushion plate and no wear can occur at the periphery of the

orifice j in the closure member occupied by the ring Risk of stalling

of the closure member or of detrimental movement of the said member in

its own plane relatively to the seating is thereby effectively

obviated.

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* 5.8.23.4; 93p

* GB786096 (A)

Description: GB786096 (A) ? 1957-11-13

Work holding device



Date of Application and filing Complete Specification: April 21, 1955.

786,096 No 11560/55.

)t)' I Application made in United States of America on April 30, 1954.


Index at acceptance:-Classes 60, 02 H 1; 83 ( 3), W( 7 QA 211); and

1451 L 5 E, 03 C.

International Classification:-B 22 d, B 24 b, B 27 b, f.


Work Holding Device We, MAGNA ENGINEERING CORPORATION, a Corporation

duly organized under the lows of the State of California, United

States of America, of 110 Linfield Drive,

Menlo Park, State of California, United States of Anmerica, 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

partieularly described in and by the following statement:-

This invention relates to a work holding device, and more particularly

to a work clamping mechanism especially adapted for mounting on a

miter gage frequently employed in conjunction with euttin tools such

as circular saws, band saws, sanders and grinding discs However, the

invention may be employed for the holding or clamping of any type of

work irrespective of the operation intended to be performed on such

work.

With respect to cutting tools, such as a circular saw, in which work

such as 2,5 lumber is moved along a work table past the rotating saw

which cuts the same and with which a miter gage is often employed for

positioning the work at a desired cutting angle, it is the prevalent

practice for the operator to hold the work against a work abutment

face of the miter gage, by means of his two hands positioned at one

side of the cutting tool Such manual holding of the work with two

hands presents safety hazards Furthermore, it is not conducive to

accuracy because of the development of a certain amount of so-cealled

"creep" toward the tool, with the result that the work is not cut

squaie, or' is cut at an angle off one or two degrees.

Although work hold-down or clamping mechanisms have been provided in

the past for clamping the work, in an attempt to overcome the

objections to holding the work with two hands, they have not been all

to be desired and consequently have not met with popular use This is

so because they cannot be set up quickly and easily or adjusted

rapidly, operated quickly, and they do not present the 50 ultimate in

safety and accuracy This invention is designed to overcome the

problems related.

Summarizing the invention, the work holding device comprises a hand

grip part, 55 work clamping means movably connected to the hand grip

part, and actuating means associated with the grip part and connected

to the clamping means for moving the clamping means into clamping

position 60 against the work; the grip part and clamp actuating means

being adapted to be held and operated with one hand so as to leave the

other hand, usually the left hand, free for holding the work 65 The

clamping means includes elements that can be quickly adjusted to

position a work engaging element of the clamping means a short

distance above the work to be cut; and the clamp actuating means is 70

of such character as to bring the work engaging element in contact

with the work by mere squeezing of a hand on the grip part Thus, when

the device is fixedly supported on a conventional miter gage, 75 the

work can he held down in fixed position by gripping of the grip part

with the hand; and both the hold-down device and the miter gage are

operated by the one hand as such combination of devices is 80 pushed

toward the operating tool by the hand.

Also, the clamp actuating means is so constructed that when the work

is cut.

automatic release of the work clamping 8 $ means can be effected by

mere release of the clamp actuating means by the hand.

Hence, when cutting off a plurality of successive smaller pieces from

the same piece of work or operating on another 90 2 786,0 6 piece of

work of substantially the same thickness, the operation of shifting

the work to be cut into smaller pieces or replacement with a new piece

of work may be quickly and easily performed without the necessity of

having to make any adjustment for releasing the -work, and

readjustments for clamping the work.

As a result of the described arrangement, there is great safey for the

operator because having merely to hold one hand on the grip part

during the working operation, his other hand is free to hold the work

at a position remote from the operating tool In addition, the support

arrangement of the device on the miter gage is such that there is

substantially no creeping of the work, thus providing great accuracy

in the work operation.

From the preceding summary, it is seen that this invention has as its

objects, among others, the provision of an improved, simple and

economical one hand operable work holding device particularly adapted

for use in conjunction with an instrument such as a miter gage, and

which provides great safety in operation, requires substantially no

adjustment thereof to place it in operation, will not cause creeping

of the work to thus insure accurate operation on the work, and which

is easy to operate Other objects of the invention will become apparent

from the following more detailed description in which reference is

made to the accompanying drawings.

In the drawings:

Fig 1 is an isometric view illustrating the work holding device of the

invention operated with one hand in conjunction with a miter gage

slidably mounted on Ihe work table of a rotary saw tool.

Fig 2 is a side elevational view of the device mounted on a miter gage

which provides a supporting base structure therefor; the customary

miter gage bar being broken away to shorten the viewr.

Fig 3 is a top plan view looking in the direction of arrow 3 in Fig 2

with the miter gage omitted from the view.

Fig 4 is a top plan view of the miter .age looking in the direction of

arrow 4 in Fig 2; an end portion of the miter gage bar being omitted

from the view and a portion of the miter gage protractor body being

omitted to shorten the view.

Fig 5 is a longitudinal sectional elevation of the device mounted on

the miter gage, with an end portion of the o miter gape bar omitted to

shorten the view The broken lines illustrate the movable clamping

means of the device, the actuating means therefor and the work in work

clamping position.

Fig 6 is a transverse section across the handle portion of the grip

part of the device, looking in the direction and taken in a plane

indicated by line 6-6 in Fig a.

Fig 7 is a similar view looking in the 70 direction and taken in a

plane indicated by line 7-7 in Fig 3.

Fig 8 is a fragmentary longitudinal sectional view at the bottom of

the means adapted to engage the work, illustrating 75 the mounting of

a work press shoe employed for such purpose.

Fig 9 is a fragmentary horizontal seetion, looking in the direction

and taken in a plane indicated by line 9-9 iii 80 Fig 5.

As previously related, the hold-diown) device hereof is of general

applicability but is particularly co-operable with a miter gage The

miterage is of mioie 85 or less conventional construction and

coniprises the usual miter Qaae liar 2 provided with longitudinally

extendin slot 3 co-operable with screw 4 providing adjustment for

accurate sliding fit of thego bar in guidewvav 6 if a tool work table

7.

A circular saw S is shown for purposes of illustration as the work

operating tool but, as previously related other operat-ii {r tools may

be employed 95 The usual protractor body 9 of the miter gage is

pivotally mounted for turnin movement on bar 2 lay means of a collar

11 fixed in the underside of body 9 and which is journalled in bar 2

as is 100 illustrated in Fig 3 Collar 11 is internally threaded; and a

screw 12 detachably holds the parts together while at the same time

allows free turning of body 9 on bar 2 105 At its front, bodv 9 has

transverse, accurately machined and flat, vertical work abutment face

13 against which the work is held: and the rear part of body 9 is

provided with the usual protractor 110 scales 14 and with arcuate slot

16 adiacent such scale A stud 17 fixed to bar 2 extends tlhroug>h slot

16: and a knurle(d nut 18 is screwed on stud 17 to clamp protractor

body 9 at any predetermined 115 angular position depending on the

angle at which it is desired to cut the work.

Customary means is employed on the gange for deteriuinin fixed stop

positions wherein abutment face 12 is at 905 and 120 450 angles with

respect to the longitudlinal center line of bar 2 Such stop momns

comprises adjustable set screwrs 19 mounted in bosses 21 extendinlg

from the underface of pirotractor body 9 in in 125 areute recess at

such underface and -wibe are co-operable with a longitudinally movable

stop pin 22 slidahly mounted in a pedestal 2 ' fixedly bat detachably

secured to the rear end of bar 130 786,096 786,096 2 by screws 24 On

the top face of pedestal 23 is an index plate 26 cooperable with

protractor scale 14; the index plate being held in adjusted position

by a set screw 27 which passes through an elongated slot in plate 26.

The work holding device is detachably miotunted on the described type

of miter rage which thus provides a supporting 13 base structure

therefor Such work holdin_ device comprises the following main parts A

hand grip part 31 having a pistol-like handle portion 32 arcuately

shaped to conform to a hand gripping the same, and extending upwardly

from and mounted on pedestal 23; a work clamping part 33 movably

connected to grip part 31 at the front upper end thereof for up and

down movement in an upright direction, and including detachably

mounted clamping arm 34, and work engaging means 36 adjustably mounted

on such arm for both longitudinal and vertical movement with respect

thereto; and automatically releasahle actuating means 35 associated

with grip part 31 and connected to work clampig part 33 to move the

same Actuating means 35 is operable by the hand engaging handle

portion 32, and is automatically releasable upon release of such hand.

(trip part 31 comprises right and left hand mating sections 37 which

form a hollow interior 38, and provide a horizon38 tal forwardly

extending top portion 39 at the upper end of handle portion 32; the

mating sections 27 being detachably held together by a pair of lower

screws 41 and a pair of upper screws 42 The lower left hand screw 41

appearing in Figs 2 and 5, passes through spaced ears 42 on handle

portion 32 and through a boss 44 on pedestal 23, to thus provide one

point of support of the grip part on the rear end of miter gage bar 2

Another point of support is provided for the grip part 31, which is

spaced forwardly from such rear point, by means of an upright stud 46

fixed to protractor body 9 The upper end of stud 46 is rotatably

journalled in mating sections 37 of the grip part.

For securing the grip part to stud 46, the stud is provided with an

annular recess 5547 at its upper end, which forms a head A 8 overlying

a shoulder 49 formed in mating sections 37 Since stud 46 can turn in

the fflrip part free unimpeded movement of protractor body 9 is not

affected Because of spaced points of attachment of grip part 31 on the

supporting base structure at one side of the work 50, great stability

obtains to thus obviate creeping of the work held by the work clamping

part 33 in the manner to be described more fully later.

Actuating means 35 for work clamping part 33 comprises a generally

L-shaped lever 51 within the hollow interior 38 of the grip part Lever

51 has a horizontal 70 portion 52 pivotally mounted on the left hand

upper screw 42 appearing in Fig 5, projecting forwardly of such screw

42 to provide means for detachable but fixed connection of lever 51

with work clamping 75 part 33 in a manner to be described.

Adjacent its lower end, lever 51 engages in a -slot 53 formed in a

transverse key member 54 fixed on a trigger 56 mounted in handle

portion 32 for floating move 80 ment; the side edges of the key 54

being freely slidably mounted in opposite guideways 57 formed on the

inside faces of the respective mating sections 37 Trigger 56 projects

freely through an elongated 85 slot 58 formed by the mating sections

37 at the underside of handle portion 32, and has an elongated arcuate

underface 59 extending substantially the length of handle portion 32

and which can be com 9 g fortably grasped by the four fingers of a

hand to press the trigger inwardly.

Stop members 61 are provided at the upper and lower ends of the

trigger, engageable with portions of the inside of 95 handle portion

32 to preclude the described lever and trigger assembly from falling

out of the handle portion Resilient means in the form of a coil spring

62 is interposed between the inside of handle 100 portion 32 and a

spring abutment pad 63 at the lower end of lever 51 for resiliently

thrusting the work clamping part 33 to non-clamping position At one

end, spring 62 is seated in a recess 64 in handle 105 portion 32, and

at the opposite end it is centered about a centering boss 66 on

abutment face 63 Since grip part 31 is made of two mating sections 37

held together by detachable screws, it is readily 110 apparent that

with lever 51, trigger 56 and spring 62 properly positioned between

the parts, and the two mating sections 37 properly positioned over

head 48 of stud 46, the grip part can be quickly assembled 115 and

attached to the miter gage.

From the preceding description, it is seen that when the grip part of

the device is held merely by one hand and trigger 56 squeezed by the

fingers of such hand, 120 as is illustrated in Fig 1, work clamping

part 33 will be moved downwardly from the full line position shown in

Fig.

to the dotted line position As long as the trigger is held squeezed,

the work 50 125 will be clamped firmly; and by mere movement of the

hand forwardly, the entire miter gage with the work and the clamping

device, can be moved along work table 7 so that the work can be cut

130 786,096 by the cutting tool S Because spring 62 urges work

clamping part 33 to nonclamping position, the work will liecome

automatically released by mere release of the trigger by the hand.

Arm 34 of work clamping part 33 projects in cantilever fashion

outwardly and forwardly from projection 52 of lever 31 and has an end

recess 71 in which lever projection 52 seats with a close fit When

arim:34 is seated on lever projection 52.

it is detachablv but firmlv held thereon bay a set screwv 72, and

extends beyond thie front of work abutment face 1, of protractor body

9.

The work engraging means 36 of the clamping part is adjustably

supported on clamping arm 34 for both vertical and lononitudinal

adjustment For this purpose an elongated slot 73 is formed in arm 34

and all upright screw threaded post 74 extends freely through slot 73

so as to be longitudinally adjustable therein.

Post 74 is reetangularly shaped in crosssection as can be seen best

fromic Fig 3 so that it can not turn in slot 73.

Vertical adjustment of post 7-4 relative to arm 34 is provided by

means of a pair of nluts 76 screwved on the post, one above and one

below the arm By adjusting the hleight of nuts 76 on post 74 the

distance of the bottom of the post from the work can be selected so

that the work engagin means can initially clear the work; and by

tightening both nuts 76 against arm 71 post 74 call be fixedly held on

the arm.

At its lower end, post 74 carries a work uress shoe 77 which is

loosely riouitdd on a pin 78 fixed to the post, so that the shoe may

have a limited amount of universal movement to engage evenly the w:ork

when the work clamping part is brouoght into position, to clamp the

work.

Detachable mounting of arm 34 of work clamping part 33 on lever

projection 52 w-hielh is a functional part of grip part :1 insofar as

the mountingl assembly is concerned, is an important feature This is

so because in case it is desired to operate on work wl hich is so high

that it cannot 1 he placed against the abutment face 13 without

clearing clamping part 9,3 at its uppermost adjusted position, the

entire clamping part can be quickly and easily detached and removed

out of the wvay merely by Ihosening set screw 72 and pulling arm 34 of

Y of lever projection 52.

In this connection, it will be noted from Fig 5, that lhen arm 34 is

removed from the grip part no portion of the grip part over bar 2

(namely the center line of the dlevie 6) extends in front of abutment

face 1.3 Consequently, worlk otherwise too hiigh can be abutted

against face 13 free of interference v\ilk the grip part: and the

device -an s Aill e emplt-ed lwithout the necessity of remo; ing: a

multiplicity of parts and subseqluently replacing them.

With respect to l Jon iitudilal adj;stmlenlt f 70 post 74 on clarilpin

1 a arm 4 I this is an important feature hecause when the protractor

bod is tm ned at an angile for cutting the wvork at ii angle, the poit

cani bze moved outvairdl-, t avoid interference 75 with the work

turned at such an Ole.

In operation( of tie dlev-ice the moniltiln LY thereof at spaced

lonations oln the supporting base structure in hack of post 74

provides a sturdy support for the device, 80 as previously relitedl

adll when pressure is applied to clanmp the work, the lwork will be

firmly held without creeping when it is moved against the operatin,

tool, thus insuring accuracy of the cutting or what 85 ever other

operation is being performed.

When pieces of work of the same thielkess are hzeing operated upon

post 74 can be initially vertically adjusted so that shoe 77 is

slightly a Iove the work to be 90 clamped, thus permnitting rea dy

insertion of the work under the shoe: andl clamping of the work can

ibe readilr and quiely effected in the mannter related above.

After the work has beenl operated upon 95 it can h)e replaceel with

work of similar thickness without the necessity oif hlavi to make any

adjustments wvhatsoev-er other than release of the tria','er and

replacement of the work, u ith salbse quient eliampino of 100 the

replaced woorn eise - when suecessive smaller pieces are to le cut

fhum a large piece of work N adjostment S nec I be made, as the -ulr

rh e l shifted jaierlas the triager is released an -3 tlie; 10,5

reclamped by sqnec/ino the trie cr Without a emlamn 1 Acl deriee f

tbct-pe described the -orkt is wswmll h& v ith both hands V 1 ith the

present le-ire, ofnly one hand is teaiuredl to elirnp the 110 work by

pressinii the s ec/e aetzlaein" means for the elzimmnr)in pa Il and 3

m ill such hand the or-vo all I, e mo laails the operating f-w I thuls

k in t 7 e operator 'ree to hod 1,1 the end of the wrk 115 with the

fiee b-audil whillieh enhlanees accuracy of operatin A Itbw-h the

device is partieularl adapted for use in combination with a miter gage

instrumenlt the pniciples thereof can be employed for 120 bold-down of

anly otfler tyre of work, because the entire derice can be mounted inl

the mamner described onl any other t-pe of supporting strlluctllle.

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* 5.8.23.4; 93p

* GB786097 (A)

Description: GB786097 (A) ? 1957-11-13

Improvements in or relating to bathroom cabinets and the like



Inventor:-HARRY DUNDONALD TIIURGAR.

Date of filing Complete Specification: May 2, 1956.

F 1 Application Date: May 3,19,55 Aro 12828155.

( omplete Specification Publishied: Nov 13, 1957.

Index at Acceptance:-Classes 52 '1), C 4 (B 2: B 9: F P 3: F 9); and

131, D 4.

International Classification:-A 47 b, k.

COMPLETE SPECIFICATION.

Improvements in or relating to Bathroom Cabinets and the like.

We, THURGAR BOLLE (SUCCESSORS) LIMITED, a British Company, of Orient

House, Field Street, Kettering, in the County or Northampton, 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 bathroom cabinets and the like formed, by

moulding, from thermoplastic material, and has for its object to

provide a simple arrangement of a rack supported on the inner side of

the door for receiving toothbrushes or other small articles.

According to the invention, in a cabinet formed, by moulding, from

thermoplastic material, and having a door which is recessed on its

inner side a strip member shaped to form a rack extending across the

inner side of the door engages at one end with locating means with

which it is engaged by movement in the direction of its length, and is

held in position at its other end by a pin passing vertically through

the strip member and through a lug or lugs formed on the door.

The central part of the door may be cut away to define a frame for a

mirror, the mirror being held against the rear face of the frame by

the strip member.

The invention is hereinafter described with reference to the

accompanying drawings, in which:Figure 1 is a perspective view of a

cabinet according to the invention, with the door open; and Figure 2

is a sectional plan view of the door and strip member taken on the

longitudinal centre line of the strip member.

Referring to the drawings, the cabinet lPrice 3 s 6 d l body 10 is an

integral moulding of approximately rectangular shape, a shelf 11 being

formed integral with it, and a pair of hinge 45 lugs 12, 12 being

integrally formed on one side edge The door 13 has a rim 14 which fits

around a rim 15 on the body 10 when the door is closed, and the door

is also formed with a pair of hinge lugs 16, 16 two 50 hinge points

(not shown) being passed each through one lug 12 and one lug 16 to

provide a hinge connection between the body and the door The front

face of the door 13 slopes forwardly from its edge as shown 55 at 17

in Figure 2, towards a central opening 18.

The door is thus recessed on its inner side An internal flange 19,

spaced from the edge of the opening 18, serves to locate 60 therein a

mirror 21, and a strip member 22 extending across the inner side of

the door in the recess, is formed to constitute a rack for

toothbrushes, and also serves to hold the mirror in position 65 The

strip member 22 is of channel shape in cross section, with outwardly

projecting flanges 23 at the edges of its side walls, and is tapered

at its ends in the direction of its depth to conform to the shape of

the door 70 The base of the channel is cranked at its ends, as shown

at 24 in Figure 2, so that the centre portion, as viewed from the

inside of the cabinet door, is set back somewhat relative to the ends

The side walls of the 75 centre portion of the channel are formed with

four pairs of cut-outs 25, each pair being joined by a slot in the

base of the channel of less width than the cut-outs.

Transverse walls 26 in the channel between 80 the cut-outs are

provided for stiffening purposes.

A tapered socket 27 on the inside of the door receives a tapered

tongue 28 on one 786,097 L_ end of the strip member 22, and a lug 29,

also on the inside of the door, fits between the side walls of the

strip member 22 at the other end of the latter, the said side walls

and the lug being formed with holes to receive a vertical pin 31 The

lug 29 is conveniently hollow, as indicated in Figure 2 The socket 27

and lug 29 are placed one adjacent each vertical edge of the door, at

about the middle of its height, the socket 27 being horizontally

aligned with a catch member 32 on the edge of the door The catch

member, when the door is closed, engages the rim of the body to hold

the door 13 in the closed position, and the socket serves to stiffen

the door in the region of the said catch member.

To assemble the mirror 21 and the strip member 22, the mirror is

placed in position, the tongue 28 on the strip member is inserted

longitudinally into the socket 27, and the other end of the strip

member is fitted over the lugs 29, so that the holes in the side walls

of the strip member and in the lug come into alignment The pin 31 is

then pushed through the holes to secure the parts together.

Toothbrushes can be supported in the strip member by passing the

handles downwardly through the cut-outs 25.

The door, instead of having the shape shown in the transverse section

in Figure 2, may be of other shapes, for example having a flat front

and a rearward flange at its edge perpendicular to said front The

shape of the strip member is then suitably modified to conform to the

shape of the door.

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* GB786098 (A)

Description: GB786098 (A) ? 1957-11-13

Improvements in protective reflective films


A high quality text as facsimile in your desired language may be available

amongst the following family members:

BE538269 (A) US3152950 (A)

BE538269 (A) US3152950 (A) less

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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.


Improvements in Protective Reflective Films

We, MINNESOTA MINING AND MANUFACTURING COMPANY, of 900 Fauquier

Avenue,

Saint Paul 6, Minnesota, United States of

America, a Corporation organized under the laws of the State of

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 metallic-appearing protective film adapted

to be adherently attached to the surfaces of materials such as metal,

wood, glass and fabric as a tough, durable weather resistant surface

coating having a bright reflective metallic lustre.

Non-metallic as well as metallic articles may thus be given a

brilliantly reflective appearance while being effectively protected

from weathering.

The invention provides a protective and decorative metallic film

product adapted to be firmly adhered to clean surfaces, comprising a

self-supporting transparent oriented polyester film having a thickness

not exceeding 2 mils and composed of a polyester condensation product

of monomers including terephthalic and/or isophthalic acid and

ethylene glycol and/or other glycols, a brilliantly reflective metal

coating applied to one surface of said film by vapour deposition in a

vacuum, and a thin strongly adhesive coating bonded to said metal

coating.

The invention provides a method of making a protective and decorative

metallic film product adapted to be firmly adhered to clean metal and

other surfaces, comprising coating a smooth surface of an oriented

transparent film of a polyester condensation product of monomers

including terephthalic and/or isophthalic acid and ethylene glycol

and/or other glycols with metal applied by vapour deposition in a

vacuum to a thickness just sufficient to provide an opaque brilliantly

reflective metal layer, followed by a liquid solvent-containing layer

of a strongly adhesive composition from which the solvent is

evaporated.

The said adhesive coating preferably comprises a rubbery

butadiene-acrylonitrile polymer, a heat-advancing

phenol-formaldehyde resin compatible therewith and compatible

plasticizers and tackifiers.

The liquid adhesive composition may be coated directly on to the

metal-coated surface and then dried. It may alternatively be first

coated on a temporary removable carrier web and partially dried, or

completely dried and then re-activated by moistening the surface with

solvent, and finally transferred to the coated surface of the film

under squeeze-roll pressure. The remaining small proportion of solvent

is then removed by dispersion through the adhesive coating and by

evaporation.

Films can be provided in accordance with the invention which when

smoothly adhered to various surfaces give the appearance of chrome

plating. Such films are strong, tough and flexible as well as

resistant to the degradative effects of water, organic solvents and

oils, sunlight and abrasion. They may be applied over compound curves

as well as flat surfaces to form smooth and brilliantly reflective,

closely fitting surface layers, and are easily adherently retained in

place on the clean surfaces of a wide variety of materials.

So far as we are aware, it was unknown prior to our invention that

thin oriented films of the type we employ have sufficient

weather-resistance to suggest suitability for our purposes. Test

samples of our reflective films have been continuously exposed to the

weather in Texas for two years and more without losing their brilliant

shiny metallic appearance. Texas was selected because of the severe

weathering conditions which pre- vail. Non-oriented films of the type

we employ do not have adequate weather-resist ance. It is of critical

importance that thin films be employed in order to provide sufficient

stretch for conformation of the product to curved surfaces, to prevent

vandalism, and to provide an appearance of chrome plating.

A wide variety of other commercially available films have been tested

by us without finding any that was suitable for our purpose.

Methods for the application of metal vapour to the surfaces of sheet

materials under high vacuum are well known. The resulting films are

highly reflective and appear to be continuous films. However it is

found that solvents readily penetrate such metallic layers. The

application of solvent-containing adhesive compositions to various

prior art metallic coated films has frequently resulted in loss of the

initial brilliantly reflective metallic appearance. Presumably the

solvent from the adhesive penetrates the porous metal coating and

attacks the bond between the metal and the film. In other instances,

the adhesive-coated metallized film is reflective when first applied

to a surface but soon becomes dull and non-reflective on weathering.

For example, it has been found to be extremely difficult, if not

impossible, to produce weather-resistant, adhesivecoated, reflective,

metallic coatings on films of cellulose acetate, polyacrylates, vinyl

films, regenerated cellulose, and drying-oilmodified alkyd resins. The

initially bright and reflective metallic surface produced by the

vapour coating of such films is rendered dull and non-reflective by

the application to the metallic coating of solvent-containing adhesive

coating compositions, or by prolonged weathering. Attempts to apply

the adhesive layer in other ways have invariably resulted in poor

adhesion within the sheet structure, or loss of reflectivity at the

metallic surface, or deformation of the polymeric film, or some

combination of these or other deleterious effects.

As the flexible transparent film we prefer to employ an oriented

polyester film of g to 2 mil. thickness made from the polyester

condensation product of terephthalic acid and ethylene glycol. Such a

film is sold commercially under the Registered Trade

Mark " Mylar". Analogous films formed of polyester condensation

products of terephthalic acid and other glycols, of isophthalic acid

and ethylene glycol or other glycols, and of mixtures of terephthalic

and isophthalic acids with ethylene glycols or other glycols or

mixtures thereof, are also useful. The thin film must be rapidly

quenched and is then oriented, preferably in both lengthwise and

crosswise directions, by cold stretching to or almost to the yield

point. The resulting film has exceptionally high tensile strength. it

is touh, and resists bending and ldiuc. The cheniical resistance of

The film is high, and it is weather-resistant and waterproof.

The metal vapour coating is applied to the film in a vacuum chamber

operating at pressures in the neighbourhood of three microns of

mercury, or preferably at not more than one micron, depending somewhat

on the specific metal being applied. The film is usually held in

contact with a cooling plate during the deposition of the metal, in

order to prevent overheating due to radiation from the crucible in

which the metal is volatilized. Due to its ease of application and due

to the superior results obtained, aluminium is a preferred metal, but

other metals, e.g., gold. may also be employed.

Aluminium produces an appearance which is very similar to that of

chrome plating, when viewed through the film on which the metal is

deposited.

Aluminium in particular is found to obtain extremely high adhesion to

the surface of the oriented polyester film, and to provide a surface

to which the subsequently applied adhesive layer forms a firm bond.

This is surprising in view of the well-known inert nature of the

surface of the film. For example, enamels and inks applied to such

surfaces are not firmly held, showing a tendency to loosen and fall

away when the printed film is exposed to outdoor weathering.

The preferred adhesive composition of this invention consists of a

blend of rubbery butadiene-acrylonitrile polymer, a heatadvancing

phenol-formaldehyde resin compatible therewith, and various additional

modifiers as desired. The adhesive is applied as a liquid in a

volatile organic vehicle, which is then removed by evaporation to

leave a flexible and durable, hard and nontacky adhesive layer, which

may subsequently be re-activated by heating or by application of

solvent. Such an adhesive has extremely high bonding qualities with

respect to metal, wood and glass surfaces, and is capable of retaining

the composite film on such surfaces against severe weathering and

against vandalism. The dry adhesive film is adequately extensible so

that it is capable of conforming to compound surfaces to which the

product may be applied. However the adhesive is not soft and tacky.

but is essentially completely non-tacky in the dry state, so that the

coated film product may be wound up in roll form or laid up in stacks

and subsequently removed Therefrom.

Somewhat softer adhesives containing a plasticizer in amount which

renders them slightly tacky and capable of forming a strong

vandal-proof bond to metal surfaces when pressed Thereagainst without

having been activated by a volatile solvent, may be employed. However

it is found that cons en tional nressure.eisit-i.-e tape a.lhesives re

r- norrTi:!l! E - and re'c"j'e-sn- sitive at room temperature, do not

provide a vandal-proof structure and, in fact, permit the protective

film to coil away from the surface to which applied under the

influence of prolonged normal weathering.

The invention will be illustrated by reference to an example of a

product produced in accordance with it.

EXAMPLE

The carrier web consisted of a Kraft paper provided on both surfaces

with a thin but smooth continuous layer of polyethylene. It was coated

on one side with a liquid adhesive composition in a thickness

sufficient to provide a final dried film of about 1k mils.

The composition of the adhesive was as follows:

Parts by

weight

Rubbery butadiene - acrylonitrile

polymer .. . . 100

Zinc oxide ........ ..................... 10

Glycerol ester of gasoline-insoluble

pine wood resin .................. 40

Heat-advancing phenol-formalde

hyde resin compatible with the

rubbery polymer . 40

Salicylic acid ......... 7.5

Dibutyl phthalate . 3.9

Methylethyl ketone ...... ........... 400

The dibutyl phthalate and the glycol ester of gasoline-insoluble pine

wood resin are respectively representative of compatible plas

-ticizers and tackifiers.

Oriented "Mylar" polyester film as here- inbefore described, and

having a thickness of one mil, was vapour coated under vacuum with the

minimum amount of aluminium required to produce a visibly opaque

metallic layer. The surface of the aluminium, when viewed through the

transparent film, had the appearance of chrome plating, i.e., was

brilliantly reflective.

The exposed surface of the dry adhesive film on the carrier web was

activated with a minimum application of methylethyl ketone and was

then pressed against the metallized surface of the film under squeeze

roll pressure. The carrier web could then be readily stripped away,

leaving the adhesive coating firmly bonded to the metallized film. The

appearance of the film viewed from the face, or non-adhesive side,

remained unchanged.

The product was wound up into roll form for storage and shipping.

Portions were removed from the roll, the carrier web was stripped

away, the exposed adhesive surface was activated with a minimum

application of solvent, and the film was applied over a metal article

having compound curves, e.g., a motor car bumper. Sufficient tension

was applied to cause the film to fit smoothly over the entire curved

surface, and the film was pressed into place. The adhesive bonded

firmly to the clean metal. and the bond grad ually improved until

after about 24 hours at room temperature it was impossible to strip

any significant area of the film from the metal, i.e., the

installation was "vandalproof". The metallic surface, viewed through

the transparent outer film, remained brilliantly reflective despite

the temporary presence of the adhesive-activating solvent and despite

the considerable stretch imparted to the film. The amount of stretch

required to provide smooth coverage on the multicurved surface was

such that it would have been impossible to apply a thin aluminium foil

in the same manner without tearing or wrinkling the film. The

combination had the appearance of chrome-plated steel, and this

appearance was maintained after prolonged weathering. The transparent

polyester film added an illusion of depth to the appearance of the

metallic film. The film effectively protected the shiny metal surface

from the elements.

What we claim is :

1. A protective and decorative metallic film product adapted to be

firmly adhered to clean surfaces, comprising a self-supporting

transparent oriented polyester film having a thickness not exceeding 2

mils and composed of a polyester condensation product of monomers

including terephthalic and/or isophthalic acid and ethylene glycol

and/or other glycols, a brilliantly reflective metal coating applied

to one surface of said film by vapour deposition in a vacuum, and a

thin strongly adhesive coating bonded to said metal coating.

2. A product according to Claim 1 in which the said metal is

aluminium.

3. A product according to Claim 1 or

Claim 2 in which the said adhesive coating comprises a rubbery

butadiene-acrylonitrile polymer, a heat-advancing phenol-formaldehyde

resin compatible therewith and compatible plasticizers and tackifiers.

4. A protective and decorative metallic film product, substantially as

described in the example herein.

5. An article having a surface to which has been firmly bonded a

protective and decorative metallic film product according to any

preceding claim.

6. A method of making a protective and decorative metallic film

product adapted to be firmly adhered to clean surfaces, comprising

coating a smooth surface of an oriented transparent film of a

polyester condensation product of monomers including terephthalic

and/or isophthalic acid and ethylene glycol and/or other glycols with

metal applied by vapour deposition in a vacuum to a thickness just

sufficient to provide an opaque brilliantly reflective metal layer.

followed by a liquid solvent-containing layer of a strongly adhesive

composition.

from which the solvent is evaporated.

5686 5690.output

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