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* GB786094 (A)
Description: GB786094 (A) ? 1957-11-13
Phosphate compositions, their production and use
Description of GB786094 (A)
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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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* GB786095 (A)
Description: GB786095 (A) ? 1957-11-13
Cushion plates for the closure members of grid-type valves
Description of GB786095 (A)
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.
Complete Specification Published: Nov 13, 1957.
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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* GB786096 (A)
Description: GB786096 (A) ? 1957-11-13
Work holding device
Description of GB786096 (A)
PATENT SPECIFICATION
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.
Complete Specification Published: Nov 13, 1957.
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.
COMPLETE SPECIFICATION
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
Description of GB786097 (A)
PATENT SPECIFICATION
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
Description of GB786098 (A)
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.
COMPLETE SPECIFICATION
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 poly- mer, 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
metal- lic 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.