JPH0481405A - Crosslinked fine-particle aqueous dispersion and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title dispersion having no glass transition temperature and good water resistance, durability, heat resistance and anti-blocking property and suitable for coating material, etc., by subjecting a polymerizable monomer containing a polymerizable polyfunctional, monomer to emulsion polymerization using a polymer having a specific acid value as an emulsifying agent. CONSTITUTION:A polymerizable monomer (e.g. ethylene glycol dimethacrylate) containing >=15wt.% polymerizable monomer is subjected to emulsion polymerization using a polymer expressed by the formula [R1 is 6-18C alkyl; R2 to R6 are H, methyl, carboxyl, carboxymethyl, etc.; X is H, ammonium salt, amine base, alkali metal or alkaline earth metal; Y is hydrocarbon having a polymerizable unsaturated group; Z is nitrile, (substituted) phenyl, amide, etc.; (a) is 2-100; (b) is 0 or 1-50; (c) is 0 or 1-50] as an emulsifying agent to provide the aimed crosslinked fine-particle aqueous dispersion having no glass transition temperature.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a crosslinked fine particle aqueous dispersion and its crosslinked fine particle aqueous dispersion that is suitably used in industrial fields such as paints, adhesives, paper, fiber processing, molded products, and adhesives. This relates to a manufacturing method.

[Prior art and problems to be solved by the present invention] In recent years, polymer emulsions have continued to grow steadily.

There is a worldwide movement to regulate solvents from the perspective of protecting the global environment, and expectations for emulsions are increasing. However, despite intensive research on improving water resistance, light resistance, weather resistance, etc., and increasing concentration, polymer emulsions have poor water resistance and durability compared to solvent-based polymers. It was lacking in This is thought to be caused by the emulsifier used during the production of polymer emulsions, which has a low molecular weight and lacks compatibility with the resulting polymer.

An object of the present invention is to provide a crosslinked fine particle aqueous dispersion that can improve not only conventional polymer emulsions but also water resistance and durability defects caused by low-molecular emulsifiers.

Similarly, another object of the present invention is to provide a crosslinked fine particle aqueous dispersion that can improve blocking resistance and heat resistance when added to thermoplastic resins and thermosetting resins.

[Means and effects for solving the problem] The present inventors
A polymerizable monomer containing a polymerizable polyfunctional monomer of 15% by weight or more, using a polymer having a long-chain thioalkyl group at the end and a carboxyl group in the molecule and having an acid value of 200 or more as an emulsifier. The crosslinked fine particle aqueous dispersion obtained by emulsion polymerization not only dramatically improves the blocking resistance, heat resistance, adhesion, and chemical resistance of polymer emulsions, but also allows the above polymer to be used as an emulsifier. The present invention has been completed based on the discovery that water resistance and durability can be improved by this method.

That is, the present invention emulsion polymerizes a polymerizable monomer containing 15% by weight or more of a polymerizable polyfunctional monomer using a polymer represented by the following general formula (A) having an acid value of 200 or more as an emulsifier. The present invention relates to a crosslinked microparticle aqueous dispersion that has substantially no glass transition temperature and a method for producing the same.

General formula (A) (wherein, R1 represents an alkyl group having 6 to 18 carbon atoms, and R
, R,, R4, R6 and R6 each independently represent hydrogen, a methyl group, a carboxyl group, a carboxymethyl group, or a salt thereof, and X is hydrogen, an ammonium salt, an amine base, an alkali metal or an alkaline earth represents a metal, Y represents a hydrocarbon group having a polymerizable unsaturated group, Z represents a nitrile group or a phenyl group, an amide group, or a carboxylic acid alkyl ester group which may have a substituent, and a represents 2- an integer of 100, b is 0 or an integer of 1-50, and C is O or an integer of 1-50. ) The polymer represented by the general formula (A) used as an emulsifier in the present invention can be synthesized by a method such as that disclosed in JP-A-63-258913 and JP-A-63-274443. However, in terms of physical properties such as stability during emulsion polymerization and water resistance of the resulting crosslinked fine particles, the acid value must be 200 or more. Further, the molecular weight thereof is preferably in the range of 300 to 7,000, particularly 600 to 3,000. If a molecular weight outside this range is used, sufficient emulsion stability may not be obtained or water resistance may be insufficient.

In particular, when b is 1 to 50 in general formula (A), the emulsifier reacts with the crosslinked fine particles and is fixed on the surface of the crosslinked fine particles, resulting in improved blocking resistance, heat resistance, adhesion,
Chemical resistance, water resistance, and durability can be further improved.

The crosslinked fine particles of the present invention having substantially no glass transition temperature are defined as:
Refers to those without sharp endothermic peaks.

Examples of polymerizable polyfunctional monomers that can be used to produce the crosslinked fine particle aqueous dispersion include (meth)acrylic acid and ethylene glycol, 1,3-butylene glycol, diethylene glycol, 1,6-hexanediol, and neopentyl. Polyfunctional compounds having two or more polymerizable unsaturated groups in the molecule, such as esters with polyhydric alcohols such as glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylolpropane, pentaerythritol, and diventaewaswattol. Meth)acrylic acid esters; polyfunctional (meth)acrylamides having two or more polymerizable unsaturated groups in the molecule, typified by methylenebis(meth)acrylamide; molecules such as diallylphthalate, diallyl maleate, diallyl fumarate, etc. Polyfunctional allyl compounds having two or more polymerizable unsaturated groups within: Allyl (meth)acrylate, divinylbenzene, etc., which can be used alone or in combination of two or more. . The amount of the polymerizable polyfunctional monomer used is preferably 15% by weight or more, more preferably 30% by weight or more. If it is less than 15% by weight, heat resistance to the extent that it does not substantially have a glass transition point cannot be obtained.

The polymerizable monomer having a functional group capable of reacting with a carboxyl group used in the production of the aqueous dispersion of crosslinked fine particles of the present invention is used to react the crosslinked fine particles with a polymer represented by the general formula (A) used as an emulsifier. It is used for the purpose of For example, the purpose is achieved by maintaining the material at a high temperature after emulsion polymerization, and its effects include further improvements in blocking resistance, heat resistance, adhesion, chemical resistance, water resistance, and durability. Examples of the polymerizable monomer having a functional group that can react with a carboxyl group include glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate,
Epoxy group-containing polymerizable monomers such as allyl glycidyl ether; Aziridinyl group-containing polymerizable monomers such as (meth)acryloyl aziridine and 2-aziridinylethyl (meth)acrylate: 2-isopropenyl-2 -Oxazoline group-containing polymerizable monomers such as oxazoline and 2-vinyl-2-oxazoline;
One or a mixture of two or more of these can be used. The amount of these polymerizable monomers used is 0.5 to 30% by weight, more preferably 1 to IQ% by weight, based on the polymerizable monomer components used in emulsion polymerization. If it is less than 0.5% by weight, the reaction with the polymer used as an emulsifier will be insufficient, and further improvement in performance cannot be expected. On the other hand, if it is used in an amount exceeding 30% by weight, stability during emulsion polymerization and storage stability will deteriorate, which is not preferable.

Other polymerizable monomers used in the production of the crosslinked fine particle aqueous dispersion of the present invention include styrene, vinyltoluene,
Styrene derivatives such as α-methylstyrene and chloromethylstyrene; (meth)methyl acrylate, (meth)
Ethyl acrylate, butyl (meth)acrylate, etc.
(Meth)acrylic acid esters synthesized by esterification of meth)acrylic acid and alcohols of C1 to C1+: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid Hydroxyl group-containing (meth)acrylic acid esters such as monoesters with polypropylene glycol or polyethylene glycol; (meth)acrylamide, N-monomethyl (meth)acrylamide, N-monoethyl (meth)acrylamide, N,N-dimethyl (
(meth)acrylamide conductors such as meth)acrylamide, N-methylol(meth)acrylamide, and N-butoxymethyl(meth)acrylamide; vinyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloylpropyltrimethoxysilane , vinyltris(2-methoxyethoxy)silane, allyltriethoxysilane, and other polymerizable monomers having a hydrolyzable silicon group directly bonded to a silicon atom; vinyl acetate, (meth)acrylonitrile, vinyl fluoride, vinylidene fluoride , vinyl chloride, vinylidene chloride, etc.
A species or a mixture of two or more species can be used. However, in order to obtain crosslinked fine particles having substantially no glass transition temperature, the glass transition temperature of the polymer made of polymerizable monomers other than the polymerizable polyfunctional monomer is preferably 70°C or higher. , more preferably 90°C or higher. 70
If the temperature is below .degree. C., even if a polymerizable polyfunctional monomer is added, it may not be possible to obtain crosslinked fine particles having sufficient heat resistance to have substantially no glass transition temperature.

The crosslinked fine particle aqueous dispersion of the present invention uses a polymer represented by the above general formula (A) having an acid value of 200 or more as an emulsifier,
In addition, the above-mentioned polymerizable monomer containing 15% by weight or more of the polymerizable polyfunctional monomer is added, if necessary, a polymerizable monomer having a functional group capable of reacting with a carboxyl group, and the well-known method is used in an aqueous medium. It is obtained by emulsion polymerization. For example, the polymerization catalyst, water, and the acid value represented by the above general formula (A) are 2.
00 or more polymer, a method of polymerizing by simultaneously mixing polymerizable monomers containing 15% by weight or more of a polymerizable polyfunctional monomer, or the so-called monomer dropping method, braised emulsion method, seed polymerization method, multistage polymerization method, etc. The crosslinked fine particle aqueous dispersion of the present invention can be produced by the method. The polymerization temperature is 0 to 100°C, preferably 50 to 80''C1, and the polymerization time is 1 to 10 hours.

Although emulsion polymerization can be carried out by any well-known method, it is preferable to employ a pre-emulsion method in order to carry out stable polymerization up to a high non-volatile content concentration. - In polymerization methods involving bulk mixing and monomer dropwise addition methods, problems such as a rapid increase in the number of particles, poor polymerization stability, and failure to increase the concentration of nonvolatile matter may occur.

The amount of the polymer represented by general formula (A) having an acid value of 200 or more is preferably in the range of 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts of the polymerizable monomer. It is. If the amount used is less than 0.5 parts by weight, the stability of emulsion polymerization will be poor, and if it is used in excess of 20 parts by weight, water resistance and durability may be adversely affected.

As the polymerization catalyst, any conventionally known catalyst can be used. However, to obtain even better water resistance and durability, hydrogen peroxide, peracetic acid, 2.2"-azobis(2-amidinopropane) dihydrochloride, 4,4-azobis(4-cyanopentane), It is preferable to use one type or a mixture of two or more types of polymerization catalysts that do not leave sulfuric acid groups such as
The range is from 0.01 to 5 parts by weight.

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited only to these Examples. In the examples, unless otherwise specified, % means % by weight and parts means parts by weight, respectively.

Reference Example 1 180 parts of isopropyl alcohol was placed in a flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, and while blowing nitrogen, the internal temperature was raised to 81°C, and the isopropyl alcohol was heated for 10 minutes. Refluxed.

Next, a previously prepared polymerizable monomer mixture consisting of 174 parts of acrylic acid, 36 parts of n-dodecylmercaptan, and 0.42 parts of 2,2'-azobisisobutyronitrile was added over 1 hour. It was added dropwise and polymerized. After the dropwise addition was completed, it was aged for 1 hour under reflux to obtain a polymer with a solid content of 53.9% (1
) was obtained. The polymer (1) has a structure represented by the following general formula, an acid value of 645, and a number average molecular weight of 120.
0 white powdery substance.

- A polymerizable monomer mixture consisting of 0.30 parts of azobisisobutyronitrile was added dropwise over 1 hour and polymerized. After dropping, it was aged for 1 hour under reflux, and the solid content was 55.4%.
A solution of polymer (2) was obtained.

The polymer (2) was a white powder having a structure represented by the following general formula, an acid value of 256, and a number average molecular weight of 1,500.

Reference Example 2 A flask similar to Reference Example 1 was charged with 180 parts of isopropyl alcohol, and the internal temperature was raised to 81° C. while blowing nitrogen, and the isopropyl alcohol was refluxed for 10 minutes. Subsequently, 86 parts of acrylic acid, 139 parts of 2-hydroxyethyl acrylate, 36 parts of n-dodecyl mercaptan, 30 parts of isopropyl alcohol and 2,2 Reference Example 3, which had been prepared in advance, were added to the dropping funnel, stirrer, nitrogen introduction tube, Pour 180 parts of isopropyl alcohol into a flask equipped with a thermometer and reflux condenser, and heat to 80°C while gently blowing nitrogen gas.
heated to. A polymerizable monomer mixture consisting of 174 parts of acrylic acid, 36 parts of n-dodecylmercaptan, and 0.42 parts of 2.2'-azobisisobutyronitrile was added thereto.
The mixture was added dropwise over 5 hours. During the dropwise addition, the temperature was maintained at 80 to 85°C, and after the completion of the dropwise addition, the mixture was stirred at the same temperature for 1 hour to complete the polymerization. Further, 57 parts of allyl glycidyl ether and 2.1 parts of triethylbenzylammonium chloride were added to the polymer thus obtained, heated to 85°C, and reacted at the same temperature for 6 hours. Completion of the reaction was confirmed by acid value measurement. Solid content concentration 57.0
% of polymer (3) was obtained. The polymer was a pale yellow polymer having an acid value of 396 and a number average molecular weight of 1550, having a structure represented by the following general formula.

C00(:H2CO-CH, -0-CH2-CH=CH
2CH Example 1 170 parts of ion-exchanged water was placed in a flask equipped with a dropping funnel, a stirrer, a nitrogen introduction tube, a thermometer, and a reflux condenser, Reference Example 1
0°1 part of the solution of polymer (1) obtained in step 2 and 2 for neutralization.
0.037 part of 8% aqueous ammonia was added. It was heated to 70° C. while slowly blowing nitrogen gas. There 2,
5 of 2'-azobis(2-amidinopropane) dihydrochloride
% aqueous solution was added. Subsequently, 140 parts of methyl methacrylate and 60 parts of divinylbenzene, which had been prepared in advance, were added to 10 parts of a solution of polymer (1) and 2
1% by weight of a polymerizable monomer pre-emulsion that had been pre-emulsified with 3.7 parts of 8% aqueous ammonia and 90 parts of ion-exchanged water was injected. After continuing the one-part polymerization, the remaining pre-emulsion was added dropwise over a period of 3 hours. After the dropwise addition was completed, the temperature was raised to 85°C, stirring was continued for 1 hour, and then the mixture was cooled to complete the polymerization.

A crosslinked fine particle aqueous dispersion (1) with a nonvolatile content concentration of 42.2% was obtained. The crosslinked fine particles showed no endothermic peak in measurement (DSC) using a heat-compensated differential scanning calorimeter manufactured by Shimadzu Corporation, and had substantially no glass transition temperature.

Examples 2 to 4 The same operations as in Example 1 were repeated except that the polymerization initiator, polymer (1) solution, and polymerizable monomer were replaced with those shown in Table 1. , crosslinked fine particle aqueous dispersions (2) to (4) were obtained. The results are shown in Table 1.

Comparative Examples 1 to 3 All the same procedures as in Example 1 except that the solution of polymer (1) and the polymerizable monomer were replaced with those shown in Table 1.
Repeat the same operation as above to prepare a comparative crosslinked microparticle aqueous dispersion (
1゛) to (3゛) were obtained. The results are shown in Table 1.

Example 5 Crosslinked fine particle water dispersions (1) to (4) and comparative crosslinked fine particle water dispersion (1) obtained in Examples 1 to 4 and Comparative Example 1
Take 50 copies of each of °) and add Nippon Shokubai Chemical ■
5C-31,350 parts of acrylic emulsion manufactured by Co., Ltd. were added thereto and thoroughly stirred and mixed. These were dried to a film thickness of 10% on a glass plate.
Coat the film to a thickness of 13 μm and hold it at a temperature of 70°C for 5 minutes.
Dry at 0'C for 5 minutes. The blocking resistance and water resistance (appearance of the coating after immersion in ion-exchanged water for 12 hours and cellophane peel strength) of these coatings on glass plates were tested. The results are shown in Table 2.

Test method Film appearance: The transparency of the film immersed in ion-exchanged water for 12 hours was evaluated.

0 ・・・・・・ Remains transparent with no change ○ ・・・・・・
・ Slightly bluish white (×...) Cellotape peel strength that completely turns white: After soaking in ion-exchanged water for 12 hours, quickly wipe off the water on the surface and remove the coating film with a cutter knife at 1 mm intervals on the base of IOX 10. After cutting it and pressing a polyester adhesive tape on it, it was peeled off and the remaining state of the coating film was examined.

0...The coating film does not peel off at all.○...
...The paint film has partially peeled off × ...The paint film has completely peeled off Blocking resistance: When the paint films are overlapped,
Put a weight on it so that the pressure is 0.1 kg/cm",
After holding at a temperature of 50° C. for 1 hour, it was peeled off and its resistance was examined.

0...I was able to peel it off easily○...
・There was resistance but it was possible to peel it off. Scarlet fever susceptibility to fever heads was evaluated as follows.

O...No stick sound △...Low stick sound

Table 3 Example 6 Crosslinked fine particle water dispersions (1) to (4) and comparative crosslinked fine particle water dispersions (2°) and (3') obtained in Examples 1 to 4 and Comparative Examples 2 to 3 ), and 50 parts of acrylic emulsion 5C-31,325 parts were added thereto and thoroughly stirred and mixed. This was coated on a 100 μm thick PET film so that the dry film thickness was 0.3 μm, and dried at 150° C. for 1 minute. Next, a black solid base paper is passed through the copy mode of FACOM FAX, and a thermal head is applied to the coated surface of the PET film (effect of the invention). When added to conventional emulsions, the crosslinked microparticle aqueous dispersion obtained as an emulsifier and having virtually no glass transition temperature improves the blocking resistance, heat resistance, chemical resistance, and adhesion properties that have hitherto been disadvantages of emulsions. It is possible to improve water resistance and durability.

Therefore, the crosslinked fine particle aqueous dispersion can be used in paints, adhesives, paper,
It is suitably used in industrial fields such as textile processing, adhesives, and molded products.

Claims (1)

[Claims] 1. Emulsifying a polymerizable monomer containing 15% by weight or more of a polymerizable polyfunctional monomer using a polymer represented by the following general formula (A) and having an acid value of 200 or more as an emulsifier. A crosslinked fine particle aqueous dispersion obtained by polymerization and having substantially no glass transition temperature. (Note) General formula (A) ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, R_1 represents an alkyl group having 6 to 18 carbon atoms,
R_2, R_3, R_4, R_5 and R_6 each independently represent hydrogen, a methyl group, a carboxyl group, a carboxymethyl group, or a salt thereof, X is hydrogen,
It represents an ammonium salt, an amine base, an alkali metal or an alkaline earth metal, Y represents a hydrocarbon group having a polymerizable unsaturated group, and Z represents a nitrile group or a phenyl group which may have a substituent, an amide group or represents a carboxylic acid alkyl ester group, a is an integer of 2 to 100, b is 0 or an integer of 1 to 50, and c is 0 or an integer of 1 to 50. 2. Crosslinking according to claim 1, wherein at least one kind of polymerizable monomer other than the polymerizable polyfunctional monomer is a polymerizable monomer having a functional group capable of reacting with a carboxyl group. Microparticle water dispersion. 3. In the polymer represented by general formula (A), b is 1
The crosslinked fine particle aqueous dispersion according to claim 1 or 2, characterized in that the crosslinked fine particle aqueous dispersion has a molecular weight of 50 to 50. 4. Emulsion polymerization of a polymerizable monomer containing 15% by weight or more of a polymerizable polyfunctional monomer using a polymer represented by the following general formula (A) having an acid value of 200 or more as an emulsifier. A method for producing a crosslinked fine particle aqueous dispersion having substantially no glass transition temperature. (Note) General formula (A) ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, R_1 represents an alkyl group having 6 to 18 carbon atoms,
R_2, R_3, R_4, R_5 and R_6 each independently represent hydrogen, a methyl group, a carboxyl group, a carboxymethyl group, or a salt thereof, X is hydrogen,
It represents an ammonium salt, an amine base, an alkali metal or an alkaline earth metal, Y represents a hydrocarbon group having a polymerizable unsaturated group, and Z represents a nitrile group or a phenyl group which may have a substituent, an amide group or represents a carboxylic acid alkyl ester group, a is an integer of 2 to 100, b is 0 or an integer of 1 to 50, and c is 0 or an integer of 1 to 50. )