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Патент USA US2077396

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Patented Apr. 420, 1937
, 2,077,396
UNITED STATES PATENT OFFICE I‘
2,077,396 '
mors'rrmeraoor MATERIAL
William Hale Char-ch, mm... and Albert Hersh
berger, Kenmore, N. Y., assignors. by mesne as-l
signments, to E. I. du Pont de Nemours & Com
pany, Wilmington, Del., a corporation of Dela
ware
No Drawing. Application February 24, 1934,
Serial No. 712,794. Renewed November 17,
v1936
'
11 Claims.
This invention relates to ?exible and non
(CI. 91-68)- '
be incorporated ingredients which produce special
tacky', moistureproof, and, preferably also, glass
clear materials admirably suited for use as a‘
wrapping tissue.
We have found-that by incorporating rubber
or an allied substance in a moistureproo?ng com
position consisting of a wax and a cellulose de
rivative, with or without a plasticizer, and/or
with or without a gum, and/or with or without
a blending agent, the wax being present in an
amount at least equal to the quantity of the
cellulose derivative or alternatively the wax being
present in an amount less than the quantity of
the cellulose derivative, we can secure,,upon the
evaporation of the solvent at a temperature at
least equal to the melting point of the wax in the
composition, a transparent, ?exible and moisture
proof coating or ?lm which has better heat seal
' ing properties and/or anchors or adheres more
20 ?rmly to the base material to which it is applied
than similar coatings or ?lms without the rubber
constituent.
The material constituting the instant invention
consists of a base formed of a material having
a smooth, dense, non-porous surface thinly coated
on both sides with the composition hereafter
more fully explained. In the preferred embodi
ment of the invention, the base material is also
non-?brous and transparent. As illustrative ex
amples of materials which have given‘ satisfac
tory results when used as the base may be men
tioned sheeting formed of cellulosic materials,
for example, regenerated cellulose, glycol cellu
lose, cellulose acetate, sheeting formed of albu
minous materials, for example, casein, gelatin,
etc.
Bases such as “glassine" paper or other
papers having the surface characteristics men
tloned may also be utilized.
_. The coating on the sheeting, as- more fully ex
40
plained hereafter, is moistureproof, ?exible, non-_
tacky, odorless and transparent. Thus, in the
preferred embodiment, when a transparent base
is used, the ultimate product is also transparent.
effects in the coating. For example, substances
which impart a hard surface to the coating, dyes,
pigments,-etc. may be incorporated.
For the rubber constituent, pale crepe rubber 5
is preferred. However, similar or allied sub
stances, such as, for example, balata, caoutchouc
and gutta percha, and rubber derivatives, for
example, hydrogenated rubber and chlorinated
rubber, may be used. As another speci?c rubber 1o
derivative may be mentioned the thermoplastic,
resin-like, rubber derivative obtained by reacting
rubber or a rubber solution with a halide salt or '
halogenated acid of a metal having a plurality of
secondary valences, such as tin tetrachloride or 15
tetrabromide, antimony pentachloride, titanium
tetrachloride, boron trichloride, ferric chloride,
antimony trichloride, boron tri?uoride, ?uoboric
acid, chlorostannic or chlorostannous acid and
the like, as described by Thies and Clifford in 20
the “Journal of Industrial and Engineering
Chemistry”, vol. 26, page 123 (1934.). The ther-‘
moplastic, rubber derivative obtained in the
above-mentioned manner through the use of tin
compounds has been found to be particularly de
sirable as a ?lm-forming ingredient. These 25
products are commonly known as thermoplastic
rubber derivatives of the "Plioform” type. The
aforementioned rubber and like materials may be
used singly or in combination with one another. 30
As the cellulose'derivative, a soluble pyroxylin
of any desired viscosity, for example, from 1/2 sec
ond up to 60 seconds or even more, and of any
suitable nitrogen content, such as that of nitro
celluloses ordinarily used in lacquers, is preferred. 35
Though a pyroxylin of the type above mentioned
is preferred, it is also possible to use other cellu
lose derivatives, such as the higher esters, mixed
esters and ether esters, as well ,as the cellulose
ethers, such as ethyl or benzyl cellulose.
40
As the wax, para?ins, particularly the high
melting point para?ins having a melting point
above 50° C., and preferably in the neighborhood
In general, the coating may be obtained from
four types of compositions, the constituents of of 60° C. or over, are preferred. Other waxes,
such as palm wax, candelilla wax, carnauba wax, 45
which consist of the following:
' certain synthetic waxes or wax-like materials‘, or
( 1) rubber, cellulose derivative, wax, and sol
esters obtained chemically from the higher al- v
vent;
' (2) rubber, cellulose derivative, wax, plasticizer
and solvent;
.
(3) rubber, cellulose derivative, wax, resin or
blending agent, and solvent;
(4) rubber, cellulose derivative, wax, resin or
blending agent, plasticiz'er and solvent.
55
In any of the above compositions, there may
cohols and acids, such as montanic acid ester of
lauryl alcohol, “vasoline”, etc. may be used. The
wax or wax-like materials may be used singly or 50
in combination.
When the composition is of the type which in
cludes also a resin or blending agent, the ordi
nary lacquer resins and preferably those resins
which are soluble in solvents, such as toluene, ben- 55
2,077,896
2
zene, etc., are preferred. Those resins which act'
as blending agents for the wax and cellulose de
rivative and which impart a hard, non-greasy sur
face to the coating are especially desirable. As
5 illustrative examples of the particularly suitable
resins may be mentioned dammar, ester gum,
rosin, hydrogenated rosin, esters of hydrogenated
rosins with various types of mono- or polyhydric
alcohols, gum mastic, synthetic resins of the
10 type soluble or partially soluble in aromatic hy
drocarbons, etc.
When the composition is of the type which in
cludes also a plasticizer, it is possible to use the
plied to the base in a relatively thin coating; thus
the total coating thickness on both sides of'the
base ?lm may be from approximately 0.00001 to
0.00015 of an inch, 'although in certain instances
it may be possible to use coatings of somewhat
greater thickness. In the preferred embodiment
of the invention, the total coating thickness on
both sides of the ?lm will be from approximately
0.00004 to 0.00008 of an inch. When the coating
composition does not include a blending agent, 10
the coating thickness should generally be less than
the coating thickness used when the composition
contains a blending agent and should generally
ordinary plasticizers, such as dibutyl phthalate,
15 tricresyl phosphate, etc‘. Certain plasticizers may
approach the lower limits of the thickness range
agent for the wax and the cellulose derivative. As
an illustrative example for use in connection with
ethyl cellulose, dixylyl ethane may be mentioned.
When the composition is of the type which in
'20 cludes
'a blending agent, any blending agent may
be used in any suitable ‘quantity, depending on
the properties desired in the ?nal product. As il
are truly heat-scalable, that is, when the films
and coatings are of the thickness previously de
scribed they are heat-sealed, there will be pro
function both as a plasticizer and a blending
lustrative examples of blending agents which
25 have given satisfactory results may be mentioned
hydrogenated castor oil, wool grease, fatty acid
glycerides, Japan wax, ricinoleic acid and its vari
ous esters, liquid esters of rosin and hydrogenated
‘rosin, etc.
i
.
As the solvent or solvent mixture, it is pre
30
set forth above.
‘
15
The coated materials produced by this invention
duced a seal or joint which is stronger than that 20
produced by heat sealing materials of the prior
art such, for example, as that described in United
States Patent No. 1,737,187.
The following test has been devised to deter
mine and test the strength of the joints before 25
mentioned:
1
Strips of the coated material 1.5 inches wide
are superposed on one end, so that the opposite
faces of the ?lm are in contact. A seal is made
across the width of the material by imposing 30
ferred to use one which is a mutual solvent for
thereon a heated iron weighing 1,500 grams for 2
the celluiose derivative and the rubber constitu
seconds.
ents. Preferably, hydrocarbon solvents, such as
benzene, toluene, etc. and/or chlorinated hydro
seal to be made of a width of a”; of an inch, the
iron being maintained in any suitable manner
at a temperature above 130° C. and below 200° C., 35
carbon solvents, such as ethylene dichloride, tri
chlorethylin, etc., are preferred. Where the cellu
lose derivative is of a type which is not completely
soluble in such solvents alone, for instance, as in
The iron is so designed as to cause a
Two strips so sealed are
opened at the free end and placed in a stretching
device, such as a Suter testing machine, by grip
the case of pyrcxylin, additional substantial ping each end of the sheet in suitable clamps,
40 quantities of a pyrcxylin solvent, for instance, one of which is ?xed and the other of which
amyl acetate or the higher acetates, cyclohexyl is moved away at'a constant speed of 12 inches
acetate, cyclohexanone and ethyl lactate, which per minute. The force in grams required to pull
at the same time possesses solubility or swelling 1 the sheets apart is taken as a measure‘ of the
properties vfor the rubber, may be used. The strength of the bond and is referred to herein as
45 lower alcohols and esters'of the lower alcohols “heat-sealing value”.
For the purposes of this speci?cation and
and low molecular weight acids, generally as a
claims, we define moistureproof materials as
class do ‘not possess sufficient solubility character
istics, and therefore the higher members of this those which, in the form of continuous, unbroken
sheets or ?lms, permit the passage of not more
series are preferred.
The
quantitive
proportions
of
the
ingredi
than 690 grams of water vapor per 100 square
50
ents constituting the different compositions may meters per hour, over a period of 24 hours, at
vary within wide limits, depending on the degree approximately 39.5" C.-i_-0.5° C., the relative hu
of transparency, moistureproofness, the surface midity of the atmosphere at one side of the ?lm
characteristics required in the ?nished ?lm, etc. being maintained at least at 98% and the rela
The coating composition in each of the afore
tive humidity of the atmosphere at the other
55
mentioned compositions contains su?icient quan
side being maintained at such a value as to give a
tityof solvent or solvent mixture to produce a humidity differential of at least 95%.
I
solution having a solids content of from 2%-20%,
Moistureproo?ng coating compositions are de
and preferably 5%-10%, by weight.
~
?ned as those which, when laid down in the form
60 The selected composition is applied to the chosen of a thin, continuous, unbroken ?lm applied uni
base, which for convenience is now referred to as formly as a coating with a total coating thickness
regenerated cellulose sheeting, in any suitable not exceeding 0.0005 of an inch to both sides of a
manner, such as by dipping, spraying, etc. The sheet of regenerated cellulose of» thickness ap
excess coating material is then removed by scrap~ proximately 0.0009 of an inch, will produce a
‘ 65 ing or any other suitable means, and the coated
sheets transferred to a drying apparatus held at
a temperature at least equal to the melting point
of the wax in the compositiomsuch as 80° C.-110°
C. After drying, which is completed in a very
70 short interval of time, such as from 2 seconds to
3 minutes, if it is desired to remove the last traces
of solvent and restore the ?exibility to the base
of regenerated cellulose sheeting, the coated sheet
may be subjected to a humidifying~ treatment.
75
As previously mentioned, the composition is ap
as, for instance, 150° C.
coated product which is moistureproof.
For the purposes of experimental tests, espe
cially for those materials adaptable as coating
compositions, moistureproof materials include
those substances, compounds or compositions
which, when laid down in the form of a con;
tinuous, unbroken ?lm applied uniformly as a
coating with a total coating thickness not ex
ceeding 0.0005 of an inch to both sides of a sheet
of regenerated cellulose of thickness approxi
45
50
55
60
a
_
sheet which will ‘permit the passage therethrough
of not more than_690 grams of water vapor per
100 square meters per hour‘ over a period of ap
proximately 24 hours, at a temperature of 395°
0.:05" C.- (preferably 395° C.:0.25° 0.), with
a water vapor pressure differential of 50-55 mm.
(preferably 53.4:07 mm.) of mercury. For con
venience, the number of grams of water vapor
10 passed under these conditions may be referred to
as “the permeability value". An uncoated sheet
of regenerated cellulose having a thickness of ap
proximately 0.0009 of an inch will show a per
meability value of the order of 6900.
15 - From the foregoing, it is apparent that under
amyl acetate to give a solution containing 10%
solids:
9
72
9
10
The process of coating; drying and humidifying
is the same as in Example Al.
'
10
The coatings are glass-clear.
Example B2.--Same as Example B1, but substi~
tute “balata" for “pale crepe rubber".
The process of coating, drying and humidifying
_ is the same asin Example B1
The coatings are clear.
Examples of rubber-pyroxylin-wax-resin
through at least ten times as effectively as the
Example C1 .-The following ingredients in the
proportions set forth are dissolved in a mixture of
In order to more fully explain the nature of the
invention, the following illustrative examples are
set forth:
Examples of rubber-pyroxylin-wax
Example A1.—-The following ingredients in ap
proximately the‘proportions set forth are dis
.solved in 1,000 parts by weight of a solvent com
posed of 60% toluene and 40% amyl acetate:
30
'
'
Pale crepe rubber _______________________ __
Pyroxylin (51 seconds) __________________ __
Para?ln (M.-P. 60-62° C.) _______________ __
Tricresyl phosphate _____________________ __
' the passage of moisture or water vapor there
uncoated regenerated'cellulose sheet.
'
Parts by weight
the conditions set forth, a moistureproofed re
generated cellulose sheet is capable of resisting
'20
3
2,077,396
mately 0.0009 of an inch, will produce a coated
Parts by weight
Pale crepe rubber _______________________ __
10
Pyroxylin (51 seconds) ____________ __' ____ __
80
Paraffin (M. P. 60—62° C.) ___________ _-______
10
I A sheet of regenerated cellulose is coated, dried
and humidi?ed as previously described. The
product possesses a slight haze and is not abso:
lutely glass-clear. The surface gloss and bril
liance of the sheet are somewhat dull, but for
certain uses dullness is a desirable property, for
instance, in the case where these coated sheets
are used for window envelopes, the strong glare
which is sometimes considered objectionable when
60% toluene and 40% amyl acetate to give a
solution of 10% solids:
Parts by weight
Pale crepe rubber ________________________ __ 9
Pyroxylin (51 seconds) ___________________ __ 10
Para?ln (M. P. 60-62° C.) ____ __‘ __________ _._ 40
De-waxed gum dammar _________ _'_ _____ __'__ 41
The process of coating, drying and humidifying
is the sameas set forth in Example Al.
The coatings are glass-clean,
Example C2.--The following ingredients in ap
proximately the proportions set forth are dissolved
in a mixture of 60% toluene and 40% amyl ace
tate to give a solids concentration of approxi-_
mately 10%:
Parts by weight
Pale crepe rubber ________________________ __
Gum mastic _____________________________ __ 50 40
The process of coating, drying and humidifying
is the same as in Example A1.
The coatings are clear.
it is desired to read writing or printing through
the sheet at an angle is avoided.
Example A2.—The following ingredients in the
9
Pyroxylin (51 seconds) ___________________ __ 30
Paraf?n (M. P. 60-62° C.) _________________ __ l1
Examples of rubber-pyroxylin-wax-resin-plasti
cizer
proportions set forth are dissolved in the same
solvent mixture as set forth in Example Al:
.
'
Example D1.—The following ingredients in the
' proportions set forth are dissolved in a mixture of
Parts by weight
Pale crepe rubber ____ "a ________________ __
7
Pyroxylin (51 seconds) __________________ __
1.0
Para?in (M. P. 60-62" C.) ________________ __
83
The process of coating, drying and humidifying
is the same as in Example A1.
The coated sheet is clear, transparent and
possesses no haze.
Example A3.—The following ingredients are
dissolved in a solvent the same as set forth in
I Example A1:
60% toluene and 40% amyl acetate to give a solu
tion containing 10% solids:
'
Parts by weight
Pale crepe rubber ______________________ __ 4
Pyroxylin (51 seconds) __________________ __ 27
Para?in (M. P. 60-62° C.) _______________ __ 4.5 "
De-waxed gum dammar _____ __, ________ _,__ 50.5
Tricresyl phosphate ____________________ __ 14
The coating, drying and humidifying are as
set forth under Example A1.
The coatings are glass-clear. v
Parts by weight
Example D2‘.—Substitute “palm wax” for “par
Pale crepe rubber __________ _-_ ___________ _-
_ 7
a?in” in Example D1.
Pyroxylin (51 seconds) ____________ _i _____ __
10
Or Paraffin (M. P. 60—62° C.) ________________ __
60
Example D3.—Substitute “candelilla wax” for
“paraffin” in Example D1.
Re?ned carnauba wax __________________ __
13
The process and the properties of the ?nished
coated regenerated cellulose sheet are the same
as in Example A2.
'
Examples of rubber-pyroa:ylin-wax-plasticizer
Example B1.—A suf?cient quantity of the fol
lowing ingredients in the proportions set forth
vi is dissolved in a mixture of 60% toluene and 40%
60
,
‘
65
' Example D4.—Substitute 1/2 of the paraffin con- ‘
tent in Example D1 with I. G. wax E (an ester
of montanic acid).
_
Example D5.—Substitute “hydrogenated ester
gum” for “de-waxed gum dammar’? in Example
D1.
,
l
.
Example D6.—Substitute “gum mastic’? for “de
waxed gum damma'r” in Example D1.
,
.
Example D7.——Substitute “hydrogenated ‘rub
her" for “pale crepe rubber” in Example D1.
'
2,077,896
4
Example D8.-‘-Substitute ,“balata” for “pale sides
thereof with a. composition comprising a
wax, a cellulose derivative and a substance select
crepe rubber" in Example D1‘.
The method of coating regenerated cellulose, - ed from the class which consists of pale crepe
drying and humidifying is the same as in Example rubber, balata, gutta percha, caoutchouc, hydro- -
5 A1.
.
The coating may be very slightly hazy without
seriously impairing the transparency. The coated
genated rubber, chlorinated rubber and “Plio
form”, the thickness of the coatings and the pro
portions of the ‘ingredients thereof being such as
‘ ' to produce a transparent, moistureproof and ?ex
sheet may be brightened by polishing. .
ible coating, the total thickness of the coatings on
Example Bil-Substitute “pyroxylin (15 sec
10 onds)” for “pyroxylin (51 seconds)” in Example . both sides being from. 0.00001 to 0.00015 of an 10
inch, said article being moistureproof, transpar
ent and flexible.
D1.
Example D10.—-Substitute “low nitrogen ni
trocellulose (11.9% nitrogen)" for “pyroxylin (51
seconds)" in Example D1.
‘ 15
Example D11.-—The following ingredients are
dissolved in a sufficient quantity of toluene to give’
approximately 10% solution of the solids:
Parts by weigh
20 Pale crepe rubber ______________________ __ 6.5
Benzene-soluble ethyl cellulose _______ __'___ 65
Para?in (M. P. 60-62° C.) ______________ __ 8.5
De-waxed. gum dammar ________________ __ 20
The coating, drying and humidifying are the
25 same as in Example A1.
The coatings are clear.
(
Example D12.—Add 10 parts by weight of tri
cresyl phosphate to the solids mixture of Example
0 D11.
,
2. An article of manufacture suitable for use as
a wrapping tissue comprising a substantially
transparent and non-fibrous base sheet formed 15
of a material of the class which consists of cellu
losic and albuminous substances coated on both
sides thereof with a composition comprising a
wax, a cellulose derivative, a blending agent and
a substance selected from the class which consists 20
of pale crepe rubber, balata, gutta percha, caou
tchouc, hydrogenated rubber, chlorinated rubber
and “Plioform”, the thickness of the coatings and
the proportions of the ingredients thereof being
such as to produce a transparent, moistureproof 25
and flexible coating, the total thickness of .the
coatings on both sides being from 0.00001 to
0.00015 of an inch, said article being moisture
proof, transparent and ?exible.
,
Examples illustrating the use of a blending agent
Example E1 .-1The following ingredients in ap
proximately the proportions set forth are dissolved
in a mixture of 60% toluene and 40% amyl acetate
35 to give approximately a 10% solution:
Parts by weigh
Pale crepe rubber ______________________ __
transparent and non-fibrous base sheet formed
of a material of the class which consists of cellu
losic and albuminous substances coated on both
sides thereof with a composition comprising a 35
wax, a cellulose derivative, a plasticizer and a
substance selected from the class which consists
5.4
Pyroxylin (51 seconds) _________________ __ 43
4o Para?in (M. P. 60-6-2" C.) _______________ ..Y
3. An article of manufacture suitable for use 30
as a wrapping tissue comprising a substantially
6.6
of pale crepe rubber, balata, gutta percha, caou
tchouc, hydrogenated rubber, chlorinated rubber
and “Plioform”, the thickness of the coatings and 40
' Hydrogenated castor oil ________________ __ 23
the proportions of the ingredients thereof being
Tricresyl phosphate ______ _:____________ __ 23
such as to produce a transparent, moistureproof
The coating, drying and humidifying are the
45 same as in Example A1.
,
The coating may be slightly hazy or possess a
surface wax blush which may be removed, if de
sired, by polishing, bu?lng, etc.
Y Example E2.—-The following ingredients in ap
proximately the proportions set forth are dissolved
in a su?icient quantity of a mixture containing
60% toluene and 40% amyl acetate to give a solu
tion containing approximately 10% solids:
Parts by weight
55 Pale/crepe rubber ________________________ __ 4
Pyroxylin (51 seconds), __________________ __ 27
Vaseline _________________________________ __
5
'Para?in (M. P. 60-62" C.) ________________ __
1
Hydrogenated ester gum ________ __'_ _____ __ ‘50
w Tricresyl phosphate ______________________ __ 13
The method of coating, drying and humidify
ing is the same as in Example A1.
The coatings are glass-clear in transparency.
Since it is obvious that various changes and
modi?cations may be made in the above descrip
tion without departing from the nature and spirit
thereof, this invention is not restricted thereto
' except as set forth in the appended claims.
70
We claim:
.
1. An article of manufacture suitable for use as
a wrapping, tissue comprising a substantially
transparent and non-?brous base sheet formed
of a material of the class which consists of cellu
, 75 losic and albuminous substances coated on both
and flexible coating, the total thickness of the
coatings on both sides being from 0.00001 to
0.00015 of an inch, said article being moisture 45
proof transparent and flexible.
4. An article of manufacture suitable for use
as a wrapping tissue comprising a substantially
transparent and non-?brous base sheet formed of
a material of the class which consists of cellu 50
losic and albuminous substances coated on both
sides thereof with'a composition comprising a
wax, a cellulose derivative, a‘ blending agent, a
plasticizer and a substance selected from the
class which consists of pale crepe rubber, balata,“ 55
gutta percha, caoutchouc, hydrogenated rubber,
chlorinated rubber and “Plioform”, the thickness
of the coatings and the proportions of the ingre
dients thereof being such as to produce a trans
parent, moistureproof and ?exible coating, the 60
total thickness of the coatings on both sides being
from 0.00001 to 0.00015 of an inch, said article
being moistureproof, transparent and flexible.
5. An article of manufacture suitable for use
as a wrapping tissue comprising a substantially 65
transparent and non-?brous base sheet formed
of a material of the class which consists of cellu
losic and albuminous substances coated on both
sides thereof with a composition comprising a 70
wax, a cellulose derivative, a resin and a sub
stance selected from the class which consists of
pale crepe rubber, balata, gutta percha, caou
tchouc, hydrogenated rubber, chlorinated rubber
and “Plioform", the thickness of the coatings and 76
9,077,896
the proportions of the ingredients thereof being
0.00015 of an inch, said article being moisture
'
., 6, An article of manufacture suitable for use
as a wrapping tissue comprising regenerated cel
lulose coatedon both sides thereof with a compo
sition comprising a wax, a cellulose derivative
and a substance selected from the class which
consists of pale crepe rubber, balata, gutta percha,
caoutchouc, hydrogenated rubber, chlorinated
rubber and "Plioform”, the thickness of the coat
15 ings and the proportions of the ingredients there
' of being such as to produce a transparent, mois
tureproof and ?exible coating, the total thickness
a
5
an inch, said article being moistureproof, trans
such as to produce a transparent, moistureproof
and ?exible coating, the total thickness of the
coatings on both sides being from 0.00001 to.
proof, transparent and ?exible. , '
-
parent and ?exible.
_
9. An article of manufacture suitable for use
as a wrapping tissue comprising a base sheet or
film of transparent regenerated cellulose having
a transparent, moistureproof and ?exible coat
ing on each side thereof, the total thickness of the
coatings on both sides being from 0.00001 to
0.00015 of an inch', each of said coatings being
formed of a composition which consists essentially
of:
'
'10
Parts by weight
Pale crepe rubber______________________ .._
4
Pyroxylin (51 seconds) __________________ __ 27
Paramn '(M. P. 60-62°C.) ________________ __ 4.5
De-waxed gum dammar ________________ __ 50.5
of the coatings on both sides being from 0.00001, , Tricresyl phosphate____________________ -_ 14
to 0.00015 of an inch, said article being moisture
proof, transparent and ?exible.
10. An article of manufacture suitable for use
as a wrapping tissue comprising a base sheet or
7. An article of manufacture suitable for use
as a wrapping tissue comprising glassine paper
coated on both sides thereof with a composition
25 comprising a wax, a cellulose derivative and a
substance selected from the class which consists
of pale crepe rubber, balata, gutta percha, caou
?lm of transparent regenerated cellulose having 20
a transparent, moistureproof and ?exible coating
on each side thereof, the total thickness of the
coatings on both sides being from 0.00001 to‘
0.00015 of an inch, each of said coatings being
formed of a composition which consists essen 25
tchouc, hydrogenated rubber, chlorinated rubber
tially of:
and “Plioform”, the thickness of the coatings and
the proportions of the ingredients thereof being
Pale crepe rubber ____ __-_ _____________ __‘__
such as to produce a transparent, moistureproof
and ?exible coating, the total thickness of the
coatings on both sides being from 0.00001 to
0.00015 on an inch, said article being moisture
proof, transparent and ?exible.
.
8. An article of manufacture suitable for use
as a wrapping tissue comprising a cellulose deriv
ative sheet, produced by casting an aqueous cel
lulose derivative composition in film form, coated
on both sides thereof with a composition compris
40
ing a wax, a cellulose derivative and a substance
selected from the class which consists of pale .
crepe rubber, balata, gutta percha, caoutchouc,
hydrogenated rubber, chlorinated rubber and
45 “Plioform", the thickness of the coatings and the
proportio, of the ingredients thereof being such
Parts by weight
6.5
Benzene-soluble ethyl cellulose__________ _. 65.0
Para?-ln (M. P. 60-62° C.) ______ _; _______ __
8.5
De-waxed gum dammar_________________ __ 20.0
11. An article of manufacture suitable for use
as a wrapping tissue comprising a base sheet or
?lm of transparent regenerated cellulose having a 35
transparent, moistureproof and ?exible coating‘
on each side thereof, the total thickness of the
coatings on both sides being from 0.00001 to
0.00015 of an inch, each of said coatings being
formed of a composition which consists essen
tially of:
-
Parts by weight
Pale crepe rubber ________________________ __
7
Pyroxylin (51 seconds) ______________ _______.. 10
as to produce a transparent, moistureproof and , Para?in (M. P. 60—62° C.) ________________ __ 83
?exible coating, the total thickness of the coat
ings On both sides being from 0.00001 to 0.00015v 0!
WILLIAM HALE CHARCH.
ALBERT
40
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