JPS61209275A - Production of aqueous dispersion of vinyl copolymer resin - Google Patents

Abstract

PURPOSE:To produce the titled aqueous dispersion having excellent film-forming property, by polymerizing a specific hydrophilic monomer with another polymerizable vinyl monomer in a water-soluble organic solvent and adding water to the obtained vinyl copolymer resin solution to effect the dispersion of the resin. CONSTITUTION:The objective dispersion is produced by dissolving (A) 1-15pts.(wt.) of a hydrophilic monomer of formula (R1 and R2 are H, 1-4C alkyl or phenyl; R3 is H or 1-20C alkyl; X is polyoxyalkylene group composed of 60-99.9(wt)% oxyethylene unit and 40-0.1% oxypropylene unit and/or oxybutylene unit) (the average molecular weight of whole oxyethylene unit is 1,500-15,000, preferably 2,000-10,000) in a water-soluble organic solvent or its mixture with water, adding a radical initiator and (B) 99-85pts. of another polymerizable vinyl monomer [e.g. methyl (meth)acrylate] dropwise to the solution under heating and agitation to effect the polymerization of the monomers and adding water dropwise to the hot solution under heating and agitation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a new method for producing an aqueous vinyl copolymer resin dispersion. More specifically, the present invention relates to a method for producing a new vinyl copolymer aqueous dispersion that does not contain commonly used emulsifiers and protective colloids.

(Prior Art and Problems) In recent years, water-based resins have attracted particular attention because they are low-pollution, resource-saving, easy to handle, and have low risk of fire. Water-based resins are usually classified into water-soluble resins and water-dispersible resins, each with its own characteristics. Water-soluble resins produced by neutralization with amino compounds are comparable to organic solvent-based resins in workability such as coatability, and have excellent gloss and corrosion resistance on coated surfaces, but on the other hand, organic solvents are not included in the paint. 3
It contains 0 to 50% by weight, which is still unsatisfactory in terms of pollution control, and has drawbacks such as odor due to ammonia or organic amines, poor drying properties, and poor water resistance of the coating film. Furthermore, when the molecular weight of the polymer is increased, the viscosity of the solution increases significantly, resulting in the disadvantage that high molecular weight materials cannot be used.

On the other hand, water-dispersed resins obtained by emulsion polymerization or mechanical dispersion in the presence of emulsifiers or protective colloids have no relation to the viscosity of the aqueous dispersion, and therefore have a high molecular weight. It has the characteristics that it can be obtained with high concentration and relatively low viscosity, hardly any organic solvents or organic amino compounds are used, and the coating film has excellent drying properties. However, there is a limit to the ability to form a half-sided film, and the mechanical stability of the aqueous dispersion and workability such as pigment compatibility are reduced, and the gloss of the coating film is reduced. Furthermore, due to the effects of the emulsifier or protective colloid used, The drawback is that the water resistance, corrosion resistance, and adhesion of the coating film are poor. For this reason, recently, water-dispersible resins that take advantage of the advantages of both water-soluble resins and water-dispersible resins have been studied.

(Means for solving the problem) Under such circumstances, the present inventors first polymerized a polymerizable vinyl monomer in a water-soluble solvent in which polyalkylene glycol was dissolved, and then added water. We have already proposed a method for producing an aqueous dispersion obtained by dispersion, and as a result of further investigation, we have discovered a method for producing an aqueous dispersion that is more versatile and provides good physical properties, leading to the present invention. .

That is, the present invention provides a method for applying a compound having a general formula (wherein, RtlRg is H or a C8~ alkyl group or phenyl group, Rs is H or a Cl41° alkyl group, X
is 60-99.9% by weight of oxyethylene units and 40-0% of oxypropylene units and/or oxybutylene units.
．． 1% by weight of the polyoxyalkylene moiety. ) and 99 to 85 parts by weight of another polymerizable vinyl heptamer by adding water to a vinyl copolymer resin solution obtained by polymerizing 1 to 15 parts by weight of a hydrophilic monomer represented by A method for producing an aqueous copolymer resin dispersion.

The aqueous dispersion obtained by the present invention is stably dispersed without using commonly used emulsifiers or protective colloids, and the resulting coating film has excellent adhesion, water resistance, and corrosion resistance. .

The hydrophilic monomer of the general formula (1) used in the present invention includes vinyl monomers containing a hydroxy group such as β-hydroxypropyl acrylate, β-hydroxyethyl methacrylate, β-hydroxyethyl acrylate, etc., and ethylene oxide ( A) and propylene oxide and/or butylene oxide (B) (A) / (
B) A compound obtained by adding randomly or in blocks at a weight ratio of -60/4o to 99.910°1;
The above (A) and (B゛) are (A)/(B)-60/40
A polyoxyalkylene glycol in which one end group is an alkyl group of H or cl~2° and the other end group is a hydroxyl group, which was randomly copolymerized or block copolymerized at a weight ratio of ~99.9/0.1. A compound obtained by an esterification reaction with a vinyl group-containing carboxylic acid monomer such as acrylic acid, methacrylic acid, or cinnamic acid;
Examples include compounds obtained by transesterification with vinyl group-containing ester monomers and mer such as propyl acrylate and butyl acrylate.

The total average molecular weight of the oxyethylene moieties contained in such hydrophilic monomers must be in the range of 1,500 to 1 sooo, and if the average molecular weight of this moiety is less than 1,500, the vinyl polymer obtained by copolymerization If the water dispersion of the resin solution is insufficient and undesirable, and if the oxyethylene moiety exceeds 1 sooo, the number of vinyl groups that can be copolymerized per unit molecular weight of the monomer will be extremely small, and in this case as well, the amount of vinyl groups that can be copolymerized will be very small. This is undesirable because the water dispersion effect of the vinyl polymer resin solution is significantly reduced.

Furthermore, if the proportion of the oxyethylene moiety in the polyoxyalkylene moiety of the wood-philic monomer is less than 60% by weight, the degree of hydrophilicity of the wood-philic monomer decreases, and water in the vinyl polymer resin solution obtained by copolymerization decreases. This is undesirable because the dispersing power decreases, and if it exceeds 99.9% by weight, the crystallinity of the wood-philic monomer becomes high, so it is necessary to crush or heat-melt it before use, which only causes problems in handling. In addition, the solubility in the seven-mer premix is poor, making it difficult to carry out a uniform polymerization reaction, which is not preferable.

The total average molecular weight of the oxyethylene moieties of the wood-philic monomer is preferably 2,000 to 10,000. More preferably, it is 3000-8000. Further, the proportion of the oxyethylene moiety in the polyoxyalkylene moiety is preferably 75 to 95% by weight.

The amount of the above-mentioned wood-loving upper layer used is 1 to 15 parts by weight out of 100 parts by weight in total with other polymerizable vinyl monomers.

If the amount of the wood-philic monomer used is less than 1 part by weight, the resulting vinyl copolymer resin solution will not have a sufficient water dispersion effect, making it difficult to obtain a stable aqueous dispersion, which is not preferred.

On the other hand, if the amount exceeds 15 parts by weight, the water dispersion effect of the resulting vinyl copolymer resin will no longer increase much, which is not only uneconomical but also reduces the water resistance etc. of the resulting polymer, which is not preferable.

A particularly preferable amount of the hydrophilic monomer used is in the range of 2 to 10 parts by weight based on 100 parts by weight in total with other polymerizable vinyl monomers.

In the present invention, other polymerizable vinyl monomers copolymerized with the hydrophilic polymer represented by the general formula (1) include ethylenically unsaturated monomers 6 For example, methyl (meth)acrylate, (meth) Ethyl acrylate, (meth)
n-butyl acrylate, lauryl (meth)acrylate,
(meth)acrylic acid-2-hydroxyethyl, (meth)
2-hydroxypropyl acrylate, 2-hydroxy-3-chloropropyl (meth)acrylate, (meth)acrylate
Acrylic acid esters and methacrylic esters such as acrylic acid glycidyl ether, α- or β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, or their salts, acrylamide, methacrylamide, N-methylacrylamide, N- α- or β-unsaturated amites such as methylol acrylamide, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl chloride, vinylidene chloride, and vinyl halides such as fluorine-containing monomers used in various water and oil repellents, etc. kind,
Styrene, α-methylstyrene, styrene derivatives such as vinyltoluene, vinyl esters such as vinyl acetate and vinyl propionate, α-olefins, conjugated dienes such as butadiene, maleic anhydride, maleic esters, itaconic esters , ethylene, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc., and one or more of these may be used.

In the present invention, the copolymerization of the hydrophilic monomer and other polymerizable vinyl monomer is carried out in a water-soluble organic solvent or in a mixed solvent solution of a water-soluble organic solvent and water. Examples of water-soluble organic solvents include alcohols such as n-butanol, 2-butanol, propylene glycol, isopropylene glycol, methanol, and ethanol, and ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol monoethyl ether. and ketones such as methyl ethyl ketone and methyl isobutyl ketone. The amount of the above-mentioned water-soluble organic solvent is not particularly limited in the present invention, but it is usually used in the range of 10 to 100 parts by weight per 100 parts by weight of heptamer to be copolymerized.

In the present invention, when obtaining a vinyl copolymer resin solution, benzoyl peroxide, lauroyl peroxide, and tart
- organic peroxides such as butyl peroxide, tert-butyl perbenzoate, te, rtt-butyl peroctoate acetyl peroxide, 2,2'-azobisisobutyronitrile or 2,2'-azobisvalero So-called radical initiators such as nitriles such as nitrile can be used.

The method for preparing the vinyl copolymer resin solution is not particularly limited. For example, while heating and stirring a water-soluble organic solvent solution containing the wood-loving polymer of general formula (1), a radical initiator and other polymers are added. You can drop a vinyl monomer, or
Other vinyl monomers containing a radical initiator and a hydrophilic monomer may be added dropwise while heating and stirring the water-soluble organic solvent, or a combination of a water-soluble organic solvent, a radical initiator, and another polymerizable vinyl monomer may be added dropwise. It is also possible to simultaneously drop a wood-philic upper layer, or to add a hydrophilic monomer in the latter half of the polymerization of monomers to be copolymerized with a radical initiator in a water-soluble organic solvent. Water may be added to the water-soluble organic solvent used at the time, usually in an amount of 50 parts by weight or less, preferably 20 parts by weight or less, per 100 parts by weight of the water-soluble organic solvent.

The resulting vinyl copolymer resin solution is then dispersed by adding water. The vinyl copolymer resin solution can be dispersed in water by gradually adding the resin solution to the water while stirring, or conversely, by gradually adding water to the vinyl copolymer resin solution and inverting the phase. Any method of emulsification is possible. Generally, about 50% of the vinyl copolymer resin solution is
A preferred method is to heat the mixture to ~100°C, gradually add water dropwise while stirring well, and carry out phase inversion emulsification because it is easy to obtain a stable dispersion having a fine particle size.

Further, when the vinyl copolymer obtained in the present invention has acid groups, it is also possible to neutralize part or all of the acid component with a volatile alkali such as ammonia or morpholine, if necessary.

Neutralization may be carried out by dissolving it in water added during the production of the aqueous dispersion, or it may be added after the production of the aqueous dispersion for neutralization.

Such aqueous dispersions of vinyl copolymer resins can be used alone, but various pigments, plasticizers, solvents, colorants, etc. may be added to them, or modified amino resins, epoxy resins, polyester resins, acrylic resins, urethane resins, etc. It is also possible to incorporate a wide variety of water-soluble or water-dispersible resins such as resins.

(Effects of the Invention) The aqueous vinyl copolymer resin dispersion obtained by the production method of the present invention is stably dispersed without using commonly used emulsifiers or protective colloids, has excellent film-forming properties, and has excellent film-forming properties. It has coating workability and finish gloss comparable to mold resin.

The characteristic of the aqueous dispersion obtained by the production method of the present invention is that by selecting the type of monomer, it is possible to easily prepare a resin dispersion having anionic, nonionic, or cationic ionicity after water dispersion. In addition to being able to manufacture
By using them alone or in combination, it becomes possible to develop them into a wide variety of application fields.

Such aqueous dispersions of vinyl copolymer resins can be used alone, but various pigments, plasticizers, solvents, colorants, etc. may be added to them, or modified amino resins, epoxy resins, polyester resins, acrylic resins, urethane resins, etc. It is also possible to incorporate a wide variety of water-soluble or water-dispersible resins such as resins.

The aqueous dispersion of the vinyl copolymer resin used in the present invention can be directly kneaded with various coloring pigments, extender pigments, etc., and the blended liquid is better than emulsion polymers made using ordinary emulsifiers and dispersants. It has excellent dispersion stability and mechanical stability, and is characterized by extremely little problem of foam generation.

The coating composition using the aqueous dispersion of the vinyl copolymer resin obtained by the present invention can be applied by any method such as dipping, coating, spraying, or roll coating, and can be applied to wood, paper, etc. It can be applied to the surfaces of fibers, plastics, ceramics, inorganic cement base materials, iron, non-ferrous metals, etc. to impart excellent performance.

(Example) Next, Examples are given to specifically illustrate the present invention.
The present invention should not be limited only to these examples.

In addition, all parts and percentages in the examples are based on weight.

Example! 2j equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and inert gas inlet! A flask was charged with 300 parts of ethyl cellosolve as a solvent, and then 35 parts of a woodphilic heptamer represented by the formula was added, and the temperature was raised to 120° C. in a nitrogen gas stream to dissolve the hydrophilic monomer. Separately, methyl methacrylate 47 as well as nil monomer
6 parts, butyl acrylate 210 parts, methacrylic acid 14 parts
Weigh and mix the parts in advance, and also add the tertiary parts.
A weighed amount of 14 parts of butyl hydroperoxide was injected from separate dropping ports, and the mixture was uniformly dropped and polymerized over a period of 3 hours.

After the dropwise addition was completed, the temperature was further raised to 130°C and maintained for 2 hours to complete the polymerization. Thereafter, the obtained solution was cooled to 80° C., and 615 parts of water was added dropwise at the same temperature over a period of about 2 hours. Thereafter, when the mixture was cooled to 25° C., a uniform aqueous resin dispersion with a slight bluish tinge was obtained. The resulting aqueous resin dispersion is made alkaline with 5% aqueous ammonia to neutralize the carboxyl groups in the polymer. The aqueous resin dispersion had a nonvolatile content of 44.5%, a viscosity of 1250 cps, a pH of 8.2, and an average particle size of 0.2 pm or less.

Examples 2 to 9, Comparative Examples 1 to 5 In the same manner as in Example 1, the types and amounts of the solvent and hydrophilic monomer used, and the type of polymerizable vinyl monomer to be copolymerized were changed as shown in Table 2. A vinyl copolymer resin aqueous dispersion was produced. The properties of the obtained aqueous dispersion are shown in Table 3, and the properties of the vines are shown in Table 1.

Comparative Example 6 An emulsion polymer having the following composition is produced by a conventional emulsion polymerization method.

Methyl methacrylate 476 parts Butyl acrylate 210 −
Methacrylic acid 14
#Sodium dodecylbenzenesulfonate 28
l Ammonium persulfate 2.
1# ion exchange water 1094.
8 #Total 1
824.9# The resulting emulsion has a non-volatile content of 39.7
%, viscosity 245 cps, and pH 3.6.

Comparative Example 7 A water-soluble resin is produced by polymerizing the following composition in a solvent using a conventional method, followed by neutralization and dilution with water.

Methyl methacrylate 350 parts Butyl acrylate 280# Methacrylic acid 70# Butyl cellosolve 490 tert
-Butyl peroxybenzoate 7#Triethylamine 84〃Ion exchange water 490〃Total
1771 #゛The properties of the resulting water-soluble resin are non-volatile content 39.9% and viscosity 2640.
0 cps, pH 9.6.

The resin dispersions of the present invention obtained in Examples 1 to 3 and the emulsion copolymers and water-soluble resins obtained in Comparative Examples 6 to 2 were made into coatings, and the properties of the coating films are shown in Table 4. .

Procedural amendment (voluntary) April 12, 1985 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case Patent Application No. 51304 of 19852, Name of the invention Process for producing vinyl copolymer resin aqueous dispersion3, Relationship with the case of the person making the amendment Patent applicant 3-35-58 Sakashita, Itabashi-ku, Tokyo 174 (28
8) Dainippon Ink & Chemicals Co., Ltd. Representative Yo Mura
Kuni Shigeru 4, Agent: Dainippon Ink & Chemicals Co., Ltd., 3-7-20 Nihonbashi, Chuo-ku, Tokyo 103 Phone number: Tokyo (03) 272-4511 (Main representative)
8B76) Patent attorney Katsutoshi Takahashi 5, subject of amendment
:Ill, - Detailed explanation of the invention in the specification column 6゜Contents of amendment'et al°5゛1・"', -1

Claims (1)

[Scope of Claims] In a water-soluble organic solvent or in a mixed solvent solution of a water-soluble organic solvent and water, a general formula having a total average molecular weight of oxyethylene moieties of 1,500 to 15,000 ▲ Numerical formula, chemical formula, table etc. ▼...(I) (In the formula, R_1, R_2 are H or an alkyl group of C_1_ to__4 or a phenyl group, R_3 is H or C_1_ to_2
_0 alkyl group, X is oxyethylene unit 60-99
．． 9% by weight and 40-0.1% by weight of oxypropylene units and/or oxybutylene units. A vinyl copolymer resin solution obtained by polymerizing 1 to 15 parts by weight of a hydrophilic monomer represented by ) and 99 to 85 parts by weight of another polymerizable vinyl monomer, by adding water to Method for producing aqueous polymer resin dispersion.