JPS61171735A - Polymer latex for treating polyester film - Google Patents

Abstract

PURPOSE:A latex being stuck fast to a polyester sheet, having improved alcohol stability resistance, obtained by subjecting a hydroxyl group-containing (meth) acrylate and an ethylenic unsaturated acid to emulsion polymerization. CONSTITUTION:0.5-15wt% based on total monomers of hydroxyl group- containing acrylate and/or methacrylate, 0.3-10wt% ethylenic unsaturated acid monomer, and the rest of monomer copolymerizable with them are subjected to emulsion polymerization, to give a polymer latex having <=50 deg.C glass transition temperature. The use of an acrylic acid ester, or methacrylic acid ester as the copolymerizable monomer improves resistance to change in color under heating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a polymer latex for treating polyester films.

(Prior Art) Carboxyl group-containing styrene-butadiene copolymer latexes have been used for undercoating photographic films using polyester film as a base and for surface treatment of polyester sheets for electronic copying for OHP. When applying the latex to an all-polyester film or sheet, the latex is generally diluted with water and used at a solid content of 1% by weight or less. As the amount decreases, the surface of the film or sheet becomes opaque, and there is a problem that the surface of the film or sheet cannot be uniformly coated. One way to solve this problem is to add alcohol to promote wetting, but since adding alcohol to the diluted latex causes the polymer to coagulate and separate, this method cannot be used and a solution is desired. ing.

(Problems to be Solved by the Invention) The present inventors have made efforts to develop a polymer latex with alcohol resistance stability that does not cause such problems.
The inventors discovered that a polymer latex containing a hydroxyl group-containing (meth)acrylate and an ethylenically unsaturated acid could be used as the constituent components of the polymer, and completed the present invention.

(Means for Solving the Problems) The object of the present invention is to provide a polymer latex for treating polyester films, which contains (1)
0.5 to 15% by weight of acrylate and/or methacrylate containing hydroxyl groups, (0.3 to 10!i% of difunctional tylenically unsaturated acid monomers and (1) copolymerized with these monomers) This can be achieved by using a latex of a polymer obtained by emulsion polymerization of possible monomers (the remainder) and whose glass transition temperature is 50° C. or lower.

Hydroxyl group-containing acrylates and methacrylates used in the present invention include hydroquinoethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2,2-dimethylhydroxyl lobil (meth)acrylate, and 5-hydroxypentyl (meth)acrylate. acrylate, diethylene glycol quino(meth)acrylate, trimethylolpropane mono(meth)acrylenide,
Hentaerythritol mono(meth)acrylate, 2-
Examples include hydroxy-3-chloropropyl (meth)acrylate. These acrylates or methacrylates can be used alone or in combination of two or more. The amount of the monomer used is preferably in the range of 0.5 to 15% by weight. If it is less than 0.5% by weight, the stability against alcohol will decrease, and if it exceeds 15% by weight, the stability against alcohol will be saturated and it will be useless. More preferably 1
~10% by weight.

Ethylenically unsaturated acid monomers used in the present invention include acrylic acid, methacrylic acid, itaconic acid, maleic acid,
Unsaturated carbonic acids such as malic acid; monoesters of unsaturated dicardic acids such as itaconic acid monoethyl ester, fumaric acid monoethyl ester, maleic acid monoethyl ester; 2-sulfoether acrylate, 2-sulfopropyl methacrylate, Unsaturated sulfonic acids such as acrylamide pronosulfonic acid and styrene sulfonic acid can be used alone or in combination of two or more. The amount of these used is 0.3 to 10% by weight. 0.3
If it is less than 8% by weight, the adhesion to polyester fill will be insufficient, and if it is used in an amount exceeding 8% by weight, the adhesion will not change. Preferably it is 0.5 to 8 times.

Monomers copolymerizable with the above monomers are used to impart strength to the coating. Such monomers include (1)
Other acrylic esters and methacrylic esters; acrylic amide, methacrylic amide; vinyl ethers (e.g., methyl vinyl ether, vinyl butyl ether); vinyl esters (e.g., vinyl propionate, vinyl acetate, etc.); aromatic vinyl Monomers (e.g. styrene, α-methyl-styrene, divinylbenzene, etc.); Conjugated diene monomers (e.g. 1,3-butanoene, isoprene, 1,3-pentadiene, etc.); Ethylenically unsaturated nitriles ( For example, acrylonitrile,
methacrylate trile, etc.). These monomers can be used alone or in a mixture of two or more, and are used within a range where the glass transition temperature of the resulting copolymer is 50° C. or lower. If the glass transition temperature exceeds 50° C., the flexibility of the coating decreases, which is not preferable.

More preferably, the temperature is 45°C or lower. When heat discoloration resistance is required for the polymer coating, it is particularly preferable to use acrylic esters and/or methacrylic esters other than α) among the third monomers mentioned above. The acrylic esters and methacrylic esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, cyanoethyl acrylate, dimethylaminoethyl acrylate, Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, hexyl methacrylate, and sulfopropyl methacrylate.

If thermal discoloration of the polymer film is not a problem, a conjugated diene monomer or a mixture of a conjugated diene monomer and an aromatic vinyl monomer or an unsaturated nitrile may be used as the third monomer. Especially economically preferred.

The polymer latex of the present invention is produced by using the above-mentioned monomer mixture using a conventional emulsion polymerization technique.

As the surfactant used to obtain the polymer latex of the present invention, anionic surfactants are suitable;
It is also possible to use nonionic surfactants alone or in combination with anionic surfactants. Examples include higher alcohol sulfate ester salts, alkylaryl sulfonates, alkylnaphthalene sulfonates, derivatives thereof, alkyl sulfonates, polyethylene glycol, fatty acid esters of polypropylene gelicol, and the like.

Catalysts used to obtain the polymer latex of the present invention include inorganic peroxides such as persulfates and hydrogen peroxide;
Alternatively, organic peroxides such as benzoyl 14-oxide, cumenehydrono, and monooxide may be used.

Furthermore, it is also possible to use a so-called redox catalyst, which is a combination of a peroxide and a reducing agent. If necessary, mercaptans, heronated hydrocarbons, etc. can also be used as chain transfer agents.

The mode of polymerization also includes a method of polymerizing by adding the entire monomer mixture at once, a method of polymerizing while continuously adding the mixture,
Examples include a method in which a part of the mixture is used for polymerization and then the remaining monomer is added to complete the polymerization, but any polymerization mode may be used. Also, the polymerization temperature is low,
Either high temperature may be used.

The polymer latex of the present invention thus obtained is a latex that has excellent alcohol resistance stability and excellent adhesion (dense) layering properties to polyester sheets. The polymer latex of the present invention can be used for purposes such as coating the entire surface of a polyester sheet to form a smooth film, or partially coating the sheet to form unevenness on the sheet surface. can. The polyester sheet surface-treated in this manner is used as a base film for packaging, optical applications, electronic copying, condenser applications, etc., but its uses are not limited thereto.

The present invention will be specifically explained below using Examples.

Example 1 A polymerization tank was charged with 0.2 parts of sodium lauryl sulfate, 0.5 parts of potassium persulfate, and 100 parts of ion-exchanged water. Polymerization was started by adding emulsion carbonate consisting of 100 parts of a monomer mixture having the following composition, 0.3 parts of sodium lauryl sulfate, and 80 parts of ion-exchanged water, and polymerization was carried out for 4 hours while maintaining the polymerization temperature at 70°C. A polymer latex having the It body composition and glass transition temperature shown in Table 1 was prepared.

These polymer latexes were diluted to 1 to 5% by weight with a total 90% n-propyl alcohol aqueous solution, applied to an untreated polyester sheet to form a 95mm thick film, and then heated in an oven at 60 to 80°C. It was dried for 5 to 10 minutes to form a film. The properties of these films are shown in Table 2.

(Note) *1 Alcohol stability: The stability was determined by the presence or absence of coagulum when diluted with 90% n-propyl alcohol aqueous solution. *2 Adhesiveness: The painted surface was rubbed 10 times with gauze. *3 Blocking resistance: The coated surface and the untreated polyester surface were placed on top of each other, and after being held down with a load of 10y/6n2, it was peeled off and the amount of polymer attached to the polyester surface was determined. Judging from the results in Table 2, hydroxyethyl acrylate is 0
．． It can be seen that when the amount is less than 5% by weight, the alcohol stability decreases. In addition, it can be seen that when the acrylic acid content is less than 0.3% by weight and the glass transition temperature exceeds 50°C, the adhesiveness decreases. Example 2 In the same manner as in Example 1, butadiene 50
% by weight, 46% by weight of styrene, 2% by weight of methacrylic acid
, 2% by weight of hydroxyethyl acrylate (latex i), 50% by weight of butadiene, 46% by weight of acrylonitrile, 2% by weight of methacrylic acid, 2% by weight of hydroxyethyl acrylate (latex j). A polymer latex was prepared, coated on a polyester sheet in the same manner as in Example 1, and dried to form a film. What are the properties of these films? It is shown in Table 3.

Table 3

Claims (1)

[Claims] (1) 0.5 to 15% by weight of acrylate and/or methacrylate containing a hydroxyl group, (
2) Glass of the polymer obtained by emulsion polymerization of 0.3 to 10% by weight of an ethylenically unsaturated acid monomer and (1) a monomer copolymerizable with these monomers (the remainder) transition temperature is 5
A polymer latex for polyester film processing that is below 0°C.