U.S. patent application number 10/798295 was filed with the patent office on 2004-10-14 for controllable and rapid solubility rate of water-soluble polymeric films.
Invention is credited to Yang, Thomas P..
Application Number | 20040204543 10/798295 |
Document ID | / |
Family ID | 27814517 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040204543 |
Kind Code |
A1 |
Yang, Thomas P. |
October 14, 2004 |
Controllable and rapid solubility rate of water-soluble polymeric
films
Abstract
Water-soluble films are prepared from polymer blends of
polyvinyl alcohol and sulfonate polymers. The sulfo group can be
acid form, SO.sub.3H, as well as salt form of potassium, sodium,
ammonium, i.e. --SO.sub.3K, --SO.sub.3Na, and --SO.sub.3NH.sub.4.
Conventional film-forming processes can be used to produce the
films. Polymeric films prepared from the blend compositions have
unique characteristics. Their water solubility rate can be
controlled by varying the composition ratio of the polymer blend.
Their water solubility rate is increased even at a temperature of
0.degree. C. The water-soluble polymeric films can be used as
packaging materials and immersion transfer printing film.
Inventors: |
Yang, Thomas P.; (Vancouver,
CA) |
Correspondence
Address: |
David J. McGruder
OYEN WIGGS GREEN & MUTALA
#480 - 601 West Cordova Street
Vancouver
BC
V6B 1G1
CA
|
Family ID: |
27814517 |
Appl. No.: |
10/798295 |
Filed: |
March 12, 2004 |
Current U.S.
Class: |
525/56 |
Current CPC
Class: |
C08L 2666/04 20130101;
C08J 2329/04 20130101; C08L 29/04 20130101; C08L 29/04 20130101;
C08L 25/18 20130101; C08J 5/18 20130101 |
Class at
Publication: |
525/056 |
International
Class: |
C08F 016/06 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2003 |
CN |
03 1 09627.1 |
Claims
What is claimed is:
1. A water-soluble film comprising a blend of polyvinyl alcohol and
a sulfonate polymer.
2. A film according to claim 1 wherein said sulfonate polymer
contains a sulfo group in the form of --SO.sub.3M, wherein M is
hydrogen, sodium, potassium or ammonium.
3. A film according to claim 2 wherein said blend contains 0.01 to
60 weight percent of said sulfonate polymer.
4. A film according to claim 2 wherein said blend contains 0.1 to
50 weight percent of said sulfonate polymer.
5. A film according to claim 2 wherein said blend contains 1 to 40
weight percent of said sulfonate polymer.
6. A film according to claim 2 wherein said sulfonate polymer is a
homopolymer or a co-polymer formed by free-radical polymerization
of sulfonate monomers.
7. A film according to claim 6 wherein said sulfonate monomer is
derived from one of 2-chloroethylene sulfonic acid,
ethylenesulfonic acid, ethylenedisulfonic acid,
1-nitriloethylenesulfonic acid, 2-formylethylenesulfonic acid,
1-carboxyethylenesulfonic acid, 1-propene-1-sulfonic acid,
1-propene-2-sulfonic acid, 2-formyl-1-methylethylene sulfonic acid,
1-carboxy-2-methylethylene sulfonic acid,
2-methyl-1,3-propenedisulfonic acid, 1-butene-1-sulfonic acid,
1-carboxy-2,2-dimethyl-ethylene sulfonic acid, 1-pentene-1-sulfonic
acid, 1-hexene-1-sulfonic acid, 2-(p-nitrophenyl) ethylene sulfonic
acid, 2-phenylethylene sulfonic acid, 2-(p-hydroxyphenyl) ethylene
sulfonic acid, 2-(2-aminophenyl) ethylene sulfonic acid,
1-methyl-2-phenylethylene sulfonic acid, 2-(p-methoxyphenyl)
ethylene sulfonic acid, 4-phenyl-1,3-butadiene sulfonic acid,
2-(p-acetamidophenyl) ethylene sulfonic acid, 3-chloroallyl
solfonic acid, allyl sulfonic acid, 1-hydroxyallyl sulfonic acid,
2-cynoallyl sulfonic acid, 3-chloromethallyl sulfonic acid,
1-carboxyallyl sulfonic acid, 3-carboxyallyl sulfonic acid,
methallyl sulfonic acid,
2-methylene-4,4-dimethyl-1,3-disulfo-pentene,
4-methylene-4,4-dimethyl pentene sulfonic acid,
1-hydroxy-3-phenylallyl sulfonic acid, 3-phenylallyl sulfonic acid,
2-benzylallyl sulfonic acid, 2-(p-methylphenoxy) allyl-sulfonic
acid, 3-phenoxymethallyl sulfonic acid, 2-sulfoethyl acrylate,
2-sulfoethyl maleate, 3-sulfopropyl acrylate, 2-sulfonyl
methacrylate, 3-sulfopropyl acrylate, 2-sulfo-1-(sulfomethyl) ethyl
methacrylate, 3-sulfopropyl maleate, 4-sulfobutyl methacrylate,
2-(acyloxymethyl)-c-sulfuran, bis-2-sulfoethyl fumarate,
3-sulfopropyl itaconate, p-sulfophenyl acrylate,
2-(2-methylacryloxymethyl)-sulfofuran, bis(2-sulfoethyl) itaconate,
p-sulfophenyl methacrylate, bis(3-sulfopropyl) maleate,
bis(3-sulfopropyl) fumarate, bis (2-sulfopropyl) maleate,
bis(2-sulfopropyl) fumarate, 5-methyl-2-(methallyloxy) benzene
sulfonic acid, bis(2-sulfopropyl) itaconate,
ar-(2-acryloyloxyethoxy)-2-naphthalen- e sulfonic acid,
ar-(2-methacryloyloxyethoxy)-naphthalene sulfonic acid,
dodecyl-4-sulfopropyl itaconate, dodecyl-4-sulfobutyl itaconate,
n-acryloyl taurine, allylthioethyl sulfonic acid, alloxy propene
sulfonic acid, n-allyl-n-methylaminoethane-sulfonic acid,
n-(methacrylamidomethyl)- -sulfoacetamide, vinyloxybenzene sulfonic
acid, n-(p-sulfophenyl) methacrylamide,
p-[(2-vinylsulfonyl)ethoxy]-benzene sulfonic acid,
n-methyl-n-(2-vinylsulfonyl-ethyl)-p-(sodiumsulfo) benzyl amine,
dichlorostyrene sulfonic acid, 2-chlorostyrene sulfonic acid,
p-styrene sulfonic acid, p-sulfonic acid, vinyltoluene sulfonic
acid, 2-methyl styrene sulfonic acid, the potassium, sodium and
ammonium salts of each of the foregoing compounds,
4-methylene-2,2,6,6-tetramethyl-3,5-disulfohe- ptene, allyloxyethyl
sulfonic acid, allyl oxybenzene sulfonic acid, and styrene sulfonic
acid.
8. A film according to claim 2 wherein said sulfonate polymer is
made by condensation polymerization of formaldehyde with sulfonate
monomers.
9. A film according to claim 8 wherein said sulfonate monomers are
derived from one or more of aminophenol sulfonic acid,
2-amino-4-chloro-phenyl sulfonic acid, 2-amino-1-naphalene sulfonic
acid, 1-amino-8-naphthol-3,5 disulfonic acid, amino-naphalene
trisulfonic acid, aminobenzene-2,5 disulfonic acid, diaminostilbene
sulfonic acid, phenol sulfonic acid, amino-naphthol disulfonic
acid, and aminodiphenylamine methane sulfonic acid.
10. A film according to claim 2 wherein said sulfonate polymer
includes sodium sulfonic styrene.
11. A film according to claim 2 wherein said sulfonate polymer is
one of sulfonated polystyrene, sulfonated polysulfone, sulfonated
melamine-formaldehyde resin, sulfonated phenol-formaldehyde resin,
sulfonated urea-formaldehyde resin, sulfonated
naphthalene-formaldehyde resin, sulfonated ethyl cellulose,
sulfonated polyurethane, sulfonated polypropylene glycol, and
sulfonated polyethylene gylcol.
12. A film according to claim 2 wherein said sulfonate polymer has
a number average molecular weight in the range of
18,000-26,000.
13. A film according to claim 2 wherein said blend includes a
film-forming additive.
14. A film according to claim 13 wherein said additive is present
in the range of 0.1-18% by weight.
15. A film according to claim 13 wherein said additive is a wetting
agent, filler, plasticizer, antioxidant, mold-releasing agent,
biocide, anti-blocking agent, defoamer or lubricant.
16. A container made from the film of claim 2.
17. A composition for forming a water-soluble film, comprising a
blend of polyvinyl alcohol and a sulfonate polymer.
18. A composition according to claim 17 wherein said sulfonate
polymer contains a sulfo group in the form of --SO.sub.3M, where M
is hydrogen, sodium, potassium or ammonium.
Description
FIELD OF THE INVENTION
[0001] This invention relates to compositions of polymer blends
useful for preparing films by conventional industrial film
processes, and particularly to water-soluble and heat-sealable
films having a controlled water-solubility rate.
BACKGROUND OF THE INVENTION
[0002] Considerable interest has been shown recently in the use of
polyvinyl alcohol water-soluble films for packaging and bags. Such
products have a number of uses. Packaging materials contaminated by
toxic or harmful materials such as biocides, preservatives, bleach,
fertilizers and detergents, must be disposed in an environmentally
safe way. Under increasing pressure of environmental regulation, it
is often difficult and expensive to dispose of empty packages or
bags which contain residues of toxic or harmful materials. It is
highly desirable for the safety of the user of such toxic or
harmful materials to use water-soluble polymer films as packaging
films. Most of these chemicals are in powder or dust form and a
user may breathe or be exposed to them. To protect a user from
these chemicals, water-soluble bags can be used. When the chemical
product is needed, the package is immersed in water and the package
dissolves in water with its content. Airborne contamination is
therefore eliminated.
[0003] For convenience of use and to reduce handling, many chemical
products are packaged in unit containers or bags having a
pre-determined quantity. For example, products such as dyes,
detergents and cement are packaged in unit containers or bags. The
use of such containers or bags permits measured amounts of the
packaged chemicals to be used without handling the chemicals
directly, protecting users from being exposed to the chemicals.
Water-soluble films are suitable materials to prepare such unit
containers or bags. When the chemical product is needed, the
container or bag is immersed in water and the bag and its content
dissolves in water.
[0004] In the healthcare field, articles such as bedclothes from
hospitals, particularly from infectious disease hospitals, have to
be sterilized for reuse. It is important to protect workers from
contact and exposure to the used articles. Bags prepared from
water-soluble films can be used as a container and put into a
sterilizer directly without opening, to eliminate contact with
infectious disease bacteria.
[0005] Water-soluble bags prepared from polymeric films are
particularly useful where the contents are toxic or should for
other reasons not be touched.
[0006] Water-soluble films are also widely used in immersion
printing processes. These are processes for decorating products
with complex curving surfaces. Water-soluble films can suitably be
used as carriers of immersion printing plates. In immersion
printing processes, controlled water-solubility rate and stiffness
are both very important to the films floated on the water
surface.
[0007] Many techniques have been investigated to modify polyvinyl
alcohol to increase the water-solubility rate of films prepared
therefrom. They can be summarized as following: (1) degradation of
the polymer; (2) design of film structure; (3) new copolymers of
polyvinyl alcohol; and (4) modifications of polyvinyl alcohol.
[0008] U.S. Pat. No. 6,071,618 (Cook, Jr. et al.) discloses a
process for increasing the solubility rate of a water soluble
polyvinyl alcohol film. A polymeric film comprises at least one
irradiated water soluble layer. In the irradiation process, the
film is subjected to an energetic radiation treatment, such as
corona discharge, plasma, flame, ultraviolet, X-ray, gamma ray,
beta ray, and high energy electron treatment. The molecular weight
of the polymer is decreased by the degradation of the polymer
through the irradiation process to increase the solubility rate of
the polymer. The molecular weight of the polymer is increased by
crosslinking of the polymer through the irradiation process to
decrease the solubility rate of the polymer. The irradiation
equipment and process are very expensive. The patent indicates that
the water-solubility rate of the films at 0.degree. C. can be
increased.
[0009] U.S. Pat. No. 3,387,405 (Iwasyk et al.) discloses a foam
structure film of polyvinyl alcohol. A polyvinyl alcohol solution
containing gelling agents is mixed with bubbles of air under
pressure. The foam is dried to a cellular film to improve the water
solubility rate. It is a slow process and difficult to control the
gelling conditions.
[0010] U.S. Pat. No. 3,157,611 (Lindemann) discloses a polyvinyl
alcohol film plasticized by phosphate ester to improve the cold
water solubility rate. It also indicates that many plasticizers
such as glycerin, ethylene glycol, ethanol acetamide and ethanol
formamide have been suggested for polyvinyl alcohol in order to
produce a material readily dissolved in water but that they are not
effective in producing polymeric materials with improved cold water
solubility. The plasticizers disclosed in this patent have the
following disadvantages: they are humectants which absorb moisture
in high humidity conditions to make them become tacky and weak; or
they are volatile so that they are easy to migrate to their
surface. All these disadvantages will affect the water solubility
rate and other physical properties of the film. The fact that
phosphate esters are not highly compatible with polyvinyl alcohol
results in the former tending to migrate to the surface of the
latter.
[0011] U.S. Pat. No. 2,948,697 (Robertson) discloses that polyvinyl
alcohol films plasticized by combination of polypropylene glycol
and phosphate esters are improved in their water solubility rates
both at high and low temperatures. But they still suffer two
problems, namely poor compatibility between polyvinyl alcohol and
plasticizers, and the migration of plasticizers to the surface of
the films.
[0012] U.S. Pat. No. 3,106,543 (Milne) discloses a polyvinyl
alcohol modification method: an ethylene oxide is reacted with
aqueous polyvinyl alcohol solution to obtain a hydroxyethylated
polyvinyl alcohol. The films prepared from the modified polyvinyl
alcohol do not contain any plasticizers. Because the process must
be carried out in extremely dilute aqueous polyvinyl alcohol
solution in an autoclave, it is expensive.
[0013] U.S. Pat. No. 3,505,303 (Lindemann) discloses a film made of
modified polyvinyl alcohols, which is clear, colorless and readily
soluble in cold water. The patent indicates that the solubility of
a film can be raised by modifying polyvinyl alcohol through
copolymerization, but the solubility of a film in cold water is not
increased. The films disclosed have high solubility in cold water.
Under alkaline condition, acryl amide is added to some of the
hydroxyl groups of the polyvinyl alcohol molecules by an alkene
addition reaction. Because the concentration of the polyvinyl
alcohol solution is 10-20%, the process is expensive. In addition,
the acryl amides must be recovered.
[0014] It would be desirable to provide water-soluble films having
the characteristics of controllable solubility rate and rapid cold
water solubility, even at 0.degree. C.
SUMMARY OF THE INVENTION
[0015] According to one broad aspect of the invention, there is
provided a water-soluble film comprising a blend of polyvinyl
alcohol and a polymer containing a sulfonate monomer. According to
another broad aspect of the invention, there is provided a
composition comprising such blend for use in forming water-soluble
films.
[0016] The invention provides controllable and rapid solubility
rate of water-soluble polymeric films. The solubility rate of the
polymeric films of the novel polymer blends is controlled by
varying the weight percent of the sulfo-containing polymer in the
composition of the polymer blend. The higher the weight percent of
the sulfo-containing polymer in the composition of the polymer
blend, the more rapid the solubility of the polymeric film. The
solubility rate is increased at high or low temperatures, even at
0.degree. C.
[0017] When the polymeric films of the present invention are
immersed in water or floated on the surface of water, their water
solubility can be controlled at a desired rate. The polymeric films
can be used for packaging films and as a base materials of an
immersion transfer printing film.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The present invention provides polymer blend compositions of
polyvinyl alcohol and sulfonate polymers. The polymeric films
prepared from novel compositions of the invention can be obtained
by conventional industrial processes for film forming.
[0019] In this specification, the term "sulfo group" means the
functional group of sulfonic acid in the form of free acid or its
salts, i.e. --SO.sub.3M, where M is H or a cation. The term
"sulfonate monomer" means a monomer containing a sulfo group. The
term "sulfonate polymer" means a polymer containing a sulfonate
monomer. Thus, the sulfonate polymers of the invention are polymers
containing a sulfo group.
[0020] It is important that the sulfonate polymers be water
soluble. Accordingly, polymers with sulfo groups in the form of
salts which render the polymers water insoluble, or minimally
soluble, are not suitable for use in the invention. Preferably, the
sulfonate polymers have sulfo groups in the form of the free acid
or the sodium, potassium or ammonium salt, all of which are water
soluble. The lithium salt is also useful, but is not preferred due
to the higher cost of lithium salts. "Water soluble" in this
specification means that the sulfonate polymer is readily soluble
in water to an extent such that films comprising the polymer blend
compositions of the invention are commercially-practical
water-soluble films.
[0021] As used in this application, the term "polymers" is used
generically, unless otherwise indicated, to mean homopolymers,
copolymers, terpolymers, tetrapolymers, etc., and thus includes
polymers prepared using any number of monomers. The term
"copolymer" is used generically, unless otherwise indicated, to
mean polymers prepared using more than one different monomers. The
term "terpolymer" is used generically, unless otherwise indicated,
to mean polymers prepared using three different monomers. The term
"tetrapolymer" is used generically, unless otherwise indicated, to
mean polymers prepared using four different monomers.
[0022] The sulfonate polymers can include polymers formed by the
free-radical homo-polymerization or free-radical copolymerization
of sulfonate monomers. Non-limiting examples of suitable sulfonate
monomers include ones from the following compounds:
2-chloroethylene sulfonic acid, ethylenesulfonic acid,
ethylenedisulfonic acid, 1-nitriloethylenesulfonic acid,
2-formylethylenesulfonic acid; 1-carboxyethylenesulfonic acid;
1-propene-1-sulfonic acid; 1-propene-2-sulfonic acid;
2-formyl-1-methylethylene sulfonic acid; 1-carboxy-2-methylethylene
sulfonic acid; 2-methyl-1,3-propenedisulfonic acid;
1-butene-1-sulfonic acid; 1-carboxy-2,2-dimethyl-ethylene sulfonic
acid; 1-pentene-1-sulfonic acid; 1-hexene-1-sulfonic acid;
2-(p-nitrophenyl) ethylene sulfonic acid; 2-phenylethylene sulfonic
acid; 2-(p-hydroxyphenyl) ethylene sulfonic acid; 2-(2-aminophenyl)
ethylene sulfonic acid; 1-methyl-2-phenylethylene sulfonic acid;
2-(p-methoxyphenyl) ethylene sulfonic acid; 4-phenyl-1,3-butadiene
sulfonic acid; 2-(p-acetamidophenyl) ethylene sulfonic acid;
3-chloroallyl solfonic acid; allyl sulfonic acid; 1-hydroxyallyl
sulfonic acid; 2-cynoallyl sulfonic acid; 3-chloromethallyl
sulfonic acid; 1-carboxyallyl sulfonic acid; 3-carboxyallyl
sulfonic acid; methallyl sulfonic acid;
2-methylene-4,4-dimethyl-1,3-disulfo-pentene;
4-methylene-4,4-dimethyl pentene sulfonic acid;
1-hydroxy-3-phenylallyl sulfonic acid; 3-phenylallyl sulfonic acid;
2-benzylallyl sulfonic acid; 2-(p-methylphenoxy) allyl-sulfonic
acid; 3-phenoxymethallyl sulfonic acid; 2-sulfoethyl acrylate;
2-sulfoethyl maleate; 3-sulfopropyl acrylate; 2-sulfonyl
methacrylate; 3-sulfopropyl acrylate; 2-sulfo-1-(sulfomethyl) ethyl
methacrylate; 3-sulfopropyl maleate; 4-sulfobutyl methacrylate;
2-(acyloxymethyl)-c-sulfuran; bis-2-sulfoethyl fumarate;
3-sulfopropyl itaconate; p-sulfophenyl acrylate;
2-(2-methylacryloxymethyl)-sulfofuran; bis(2-sulfoethyl) itaconate;
p-sulfophenyl methacrylate; bis(3-sulfopropyl) maleate;
bis(3-sulfopropyl) fumarate; bis (2-sulfopropyl) maleate;
bis(2-sulfopropyl) fumarate; 5-methyl-2-(methallyloxy) benzene
sulfonic acid; bis(2-sulfopropyl) itaconate;
ar-(2-acryloyloxyethoxy)-2-naphthalen- e sulfonic acid;
ar-(2-methacryloyloxyethoxy)-naphthalene sulfonic acid;
dodecyl-4-sulfopropyl itaconate; dodecyl-4-sulfobutyl itaconate;
n-acryloyl taurine; allylthioethyl sulfonic acid; alloxy propene
sulfonic acid; n-allyl-n-methylaminoethane-sulfonic acid;
n-(methacrylamidomethyl)- -sulfoacetamide; vinyloxybenzene sulfonic
acid; n-(p-sulfophenyl) methacrylamide;
p-[(2-vinylsulfonyl)ethoxy]-benzene sulfonic acid;
n-methyl-n-(2-vinylsulfonyl-ethyl)-p-(sodiumsulfo) benzyl amine;
dichlorostyrene sulfonic acid; 2-chlorostyrene sulfonic acid;
p-styrene sulfonic acid; p-sulfonic acid; vinyltoluene sulfonic
acid; 2-methyl styrene sulfonic acid; the potassium, sodium and
ammonium salts of each of the foregoing compounds;
4-methylene-2,2,6,6-tetramethyl-3,5-disulfohe- ptene; allyloxyethyl
sulfonic acid; allyl oxybenzene sulfonic acid; and styrene sulfonic
acid.
[0023] The sulfonate polymers of the invention can be obtained by
the free-radical copolymerization of a sulfonate monomers and an
olefinic co-monomer. Non-limiting examples of suitable olefinic
comonomers include ones from the following compounds and groups:
acrylic acid and its salt; methylacrylic acid and its salt;
acrylates; methacrylates; acrylamide; methylacrylamide; vinyl
acetate; n-vinyl pyrrolidon; styrene; vinyl chloride;
acrylonitrile; and allyl.
[0024] Free radical initiators that may be used include
2,2'-azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide,
t-butyl peroxide, cumyl peroxide, t-butylhydro peroxide, cumylhydro
peroxide, hydrogenperoxide-ferrous sulfate.
[0025] The sulfonate polymers can be prepared by any conventional
free radical polymerization technique, such as solution
polymerization, suspension polymerization, emulsion polymerization
and bulk polymerization.
[0026] The sulfonate polymers may also be formed by the
condensation polymerization of formaldehyde with sulfonate
monomers, including sulfonate monomers of the following compounds:
aminotoluene sulfonic acid; aminophenol sulfonic acid;
2-amino-4-chloro-phenyl sulfonic acid; 2-amino-1-naphalene sulfonic
acid; 1-amino-8-naphthol-3,5 disulfonic acid; amino-naphalene
trisulfonic acid; aminobenzene-2,5 disulfonic acid; diaminostilbene
sulfonic acid; phenol sulfonic acid; amino-naphthol disulfonic
acid; and aminodiphenylamine methane sulfonic acid.
[0027] The sulfonate polymers may also be formed by direct
sulfonation or alkyl-sulfonation of the polymers. Sulfonation and
alkyl-sulfonation reagents include sulfur trioxide and its complex,
sulfuric or chlorosulfonic acid, sultone and acetyl sulfate.
[0028] The sulfonate polymers can include sulfonated polystyrene,
sulfonated polysulfone, sulfonated melamine-formaldehyde resin,
sulfonated phenol-formaldehyde resin, sulfonated urea-formaldehyde
resin, sulfonated naphthalene-formaldehyde resin, sulfonated ethyl
cellulose, sulfonated polyurethane, sulfonated polypropylene
glycol, and sulfonated polyethylene gylcol.
[0029] The number average molecular weight of the sulfonate
polymers of the invention is in the range of about 18,000-26,000,
preferably 19,000-23,000. The number average molecular weight of
the polyvinyl alcohol used for present invention is in the range of
about 7,000-13,000, preferably 8,000-11,000.
[0030] The polymer blends of the present invention preferably
contain sulfonate polymers in the range of about 0.01-60% by weight
of the blend, more preferably 0.1-50% by weight, more preferably
1-45% by weight, and most preferably 1-40% by weight. Said blends
can be prepared by any conventional industrial process for
preparing polymer blends, of which a mixing process is
preferred.
[0031] The polymeric films prepared from the blends may include
conventional film forming additives, including wetting agents,
fillers, plasticizers, antioxidants, mold releasing agents,
biocides, anti-blocking agents, defoamers, lubricants, etc.
Depending on the compositions of the blends, the quantity of the
additives is typically 0.1-18 weight %.
[0032] The polymeric films can be prepared by any conventional film
process, of which solution casting, melt extrusion and blown film
processes are more preferred.
[0033] The water solubility rate of the polymeric films can be
controlled by varying the compositions of the polymer blend. The
water solubility rate of the films depends directly on the weight
percent of the sulfonate polymers in the blends. The weight percent
of the sulfonate polymers in the blends controls the water
solubility rate of the films. The water solubility rate of the
polymeric films prepared from the novel polymer blends can be
increased to 2.4 times of that of a polyvinyl alcohol film at the
temperature of 0.degree. C.
[0034] In the following examples, the polyvinyl alcohol used has a
number average molecular weight of 7,000-13,000; and the poly
sodium styrene sulfonate used has a number average molecular weight
of 18,000 to 26,000.
EXAMPLE 1
[0035] A polymer blend of 90% by weight of polyvinyl alcohol and
10% by weight of poly sodium styrene sulfonate was prepared. The
two components were premixed and then pelletized. The composition
was formed into a film by means of a blown film process at
200.degree. C.
EXAMPLE 2
[0036] A polymer blend of 80% by weight of polyvinyl alcohol and
20% by weight of poly sodium styrene sulfonate was prepared. The
two components were premixed and then pelletized. The composition
was formed into a film by means of a blown film process at
200.degree. C.
EXAMPLE 3
[0037] A polymer blend of 70% by weight of polyvinyl alcohol and
30% by weight of poly sodium styrene sulfonate was prepared. The
two components were premixed and then pelletized. The composition
was formed into a film by a blown film process at 200.degree.
C.
EXAMPLE 4
[0038] For comparative purposes a film was made without a sulfonate
polymer. A film was cast from an aqueous polyvinyl alcohol
solution, the concentration and the average MW of which are 18 wt %
and 7,000-13,000, respectively. The solution was poured onto a
glass plate and is spread into a uniform film by a glass bar. It
was dried for 24 hours at a temperature of 45.degree. C. The dried
film was peeled off from the glass plate.
[0039] The water solubility rates of the films produced in Examples
1 to 4 were measured. Films of 4 cm.times.1 cm.times.0.03 cm
(thickness) were used. 250 ml of water in a 500 ml beaker was held
at 15.degree. C. and constantly stirred. The films were put in the
water and permitted to dissolve. The water solubility rate was
measured as the time interval between the moment the film touched
the water and the moment the film disappeared by visual inspection.
The results are summarized in Table 1.
1TABLE 1 Controllable Water Solubility Rate of the Films
Compositions of the Films (wt %) Water Solubility Rate A B at
15.degree. C. (Sec.) Ex. 1 Film 90 10 10.2 Ex. 2 Film 80 20 8 Ex. 3
Film 70 30 3 Ex. 4 Film 100 0 14.2 A = Polyvinyl alcohol B = Poly
sodium styrene sulfonate
[0040] The water solubility rates of the Example 1 film, Example 2
film and Example 3 film are 1.4, 1.8 and 8 times faster than that
of Example 4 film, respectively.
EXAMPLE 5
[0041] A blend of 91% by weight of polyvinyl alcohol and 9% by
weight of poly sodium styrene sulfonate was prepared, with 12.6% by
weight (based on the total weight of the polymers) of propylene
glycol, 1.7% by weight of sodium C.sub.12-16 olefin sulfonate and
1.7% dihydroxy ethylphenol amine. The components were premixed and
then pelletized. The composition was formed into a film by a blown
film process at 195.degree. C.
EXAMPLE 6
[0042] For purposes of comparison with the film of Example 5, a
film was made without the poly sodium styrene sulfonate. A blend of
100% by weight of polyvinyl alcohol was prepared with 12.6% by
weight (based on the total weight of the polyvinyl alcohol) of
propylene glycol, 1.7% by weight of sodium C.sub.12-16 olefin
sulfonate and 1.7% by weight of dihydroxy ethyphenol amine. The
components were premixed and then pelletized. A film was formed
into a film by a blown film process at 198.degree. C.
[0043] The water solubility rates of the films produced in Examples
5 and 6 were measured (at 25.degree. C.) by the method described
above in Example 4. The results are summarized in Table 2.
2TABLE 2 Water Solubility Rate at 25.degree. C. Film Compositions
(wt %) Water Solubility Rate A B C at 25.degree. C. (Sec.) Example
5 91 9 16 4 Example 6 100 0 16 8.4 A = Polyvinyl alcohol B = Poly
sodium styrene sulfonate
[0044] C=Propylene glycol 12.6 wt %; sodium C.sub.12-16 olefin
sulfonate 1.7 wt %; and dihydroxy ethylphenol amine 1.7 wt %.
Weight percentages are relative to the total weight of the polymers
only.
[0045] The water solubility rates of the Example 5 film is 2.1
times faster than that of Example 6 film, at 25.degree. C.
[0046] The water solubility rates of these films was then measured
at 0.degree. C., using the same method. The results are summarized
in Table 3.
3TABLE 3 Water Solubility Rate at 0.degree. C. Film Compositions
[wt %] Water Solubility Rate A B C at 0.degree. C. [Sec.] Example 5
91 9 16 9.4 Example 6 100 -- 16 22.4 A = Polyvinyl alcohol B = Poly
sodium styrene sulfonate C = Propylene glycol 12.6 wt %; sodium
C.sub.12-16 olefin sulfonate 1.7 wt %; and dihydroxy ethylphenol
amine 1.7 wt %. Weight percentages are relative to the total weight
of the polymers only.
[0047] The water solubility rates of the Example 5 film is 2.4
times faster than that of the Example 6 film, at 0.degree. C.
[0048] As will be apparent to those skilled in the art in the light
of the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from
the spirit or scope thereof. Accordingly, the scope of the
invention is to be construed in accordance with the substance
defined by the following claims.
* * * * *