JPS5937287B2 - Method for producing an aqueous dispersion composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aqueous dispersion composition that has excellent properties as a base composition for paints, adhesives, and the like.

In recent years, aqueous polymer dispersions obtained by emulsion polymerization, such as acrylic, acrylic-styrene, vinyl acetate, and ethylene-vinyl acetate, have come to be widely used in industrial applications such as paints and adhesives. I came.

However, the films formed from these conventional aqueous polymer dispersions have insufficient adhesion to metals, wood, hardened cement, plastics, etc., and often cause peeling and blistering, especially in wet conditions or at high temperatures. It had some defects. In order to improve these defects, efforts have been made to reduce the amount of water-sensitive substances such as surfactants and protective colloids contained in the aqueous polymer dispersion, and to create crosslinked structures by introducing functional groups into the polymer skeleton. Although attempts have been made to form In addition, attempts have been made to improve the water resistance of coating films by using thermosetting resins, such as epoxy resins, etc., but (1) the polymer component and epoxy resin separate during storage, and (2) the obtained It had drawbacks such as the coating film becoming cloudy and (3) insufficient improvement in water resistance of the coating film. In view of these facts, the present inventors have conducted intensive studies to find an aqueous dispersion that has good storage stability and the resulting coating film is uniform and has good water resistance, heat resistance, and adhesion. , which led to the completion of the present invention.

That is, the present invention provides (2) an epoxy equivalent of 900 to 400;
10 to 90 parts by weight of a compound obtained by reacting 0 bisphenol A type epoxy resin and methacrylic acid at a molar ratio of 1/0.1 to 1/0.5 and 20 to 80 parts by weight of acrylic acid or methacrylic acid. 90 to 10 parts by weight of a polymerizable monomer consisting of 10 to 60 parts by weight of an aromatic vinyl monomer and 5 to 50 parts by weight of an alkyl ester of α/β monoethylenically unsaturated carboxylic acid. This is a method for producing an aqueous dispersion composition obtained by uniformly mixing the components, polymerizing at a temperature of 100° C. or lower, and partially or completely neutralizing with a basic compound.

The aqueous dispersion composition produced according to the present invention provides a coating film having significantly superior water resistance, heat resistance, and adhesion compared to conventional acrylic aqueous dispersions.

Furthermore, compared to conventional epoxy resin-based or acrylic-based water dispersions combined with epoxy resin, it has excellent storage stability and provides a transparent coating film. Furthermore, the aqueous dispersion composition produced by the present invention has little variation in product quality due to production conditions, and can enjoy stable quality. In the aqueous dispersion composition produced in the present invention, it is necessary that sufficient epoxy groups remain in the composition to carry out the crosslinking reaction. A good coating film can be formed by adding a compound capable of reacting with the resulting alcoholic OH groups, ie, a crosslinking agent.

The film can also be formed by introducing a reactive functional group into the ethylenic monomer. The present invention will be explained in more detail below.

The bisphenol A type epoxy resin used in the present invention is a condensate of bisphenol A and epichlorohydrin, and has an epoxy equivalent of 900 to 4,000.

If the epoxy equivalent is less than 900, the flexibility of the coating film will be poor, while if it is more than 4000, the viscosity will be too high and a good polymer product cannot be obtained, resulting in poor storage stability of the aqueous dispersion. There is. The reaction between the epoxy resin and methacrylic acid can be carried out at a molar ratio of 1/0.1 to 1/0.5 using a reaction catalyst at a temperature of 110 to 150°C.

Catalysts include (1) alkali metal hydroxides such as K;
OH. NaOH (2) Uses an inorganic or organic salt of an alkali metal. The reaction continues until substantially free methacrylic acid is consumed. When the reaction molar ratio is less than 1:0.1, the storage stability of the resulting aqueous dispersion composition is extremely poor;
When the ratio is 0.5 or more, the production of high molecular weight during polymerization is significant;
It tends to gel during polymerization, and it is also difficult to make it solubilized in water. The polymerizable monomers used in the present invention are (a) 20 to 80% by weight of acrylic acid or methacrylic acid) 10 to 60% by weight of aromatic vinyl monomer, and (h) alkyl of α/β monoethylenically unsaturated carboxylic acid. It consists of 5 to 50% by weight of ester, and if the amount of acrylic acid or methacrylic acid is less than 20% by weight, the storage stability of the aqueous dispersion is poor, and if it is more than 80% by weight, gelation occurs during polymerization, which is not preferable. .

If the amount of the aromatic vinyl monomer is less than 10% by weight, the corrosion resistance will not be good, and if it is more than 60% by weight, the storage stability of the aqueous dispersion will be poor. Also, α/β monoethylenically unsaturated carvone is 5
If it is less than 50%, the flexibility of the coating film will be insufficient, and if it is more than 50%, the boiling water resistance of the coating film will be extremely deteriorated. Examples of the aromatic vinyl monomer used in the present invention include styrene, α-methylstyrene, and vinyltoluene. The alkyl esters of α/β monounsaturated carboxylic acids used in the present invention include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and the above-mentioned alkyl esters. Examples of the esters include alkyl esters of methacrylic acid.

In the present invention, the ratio of the reaction product (A) to the polymerizable monomer (B) is 10 to 10% of the reaction product (A).
With respect to 90 parts by weight, the amount of polymerizable monomer (B) is 90 to 1
The proportion is 0 parts by weight.

In the present invention, a polymerization initiator and, if necessary, an organic solvent and other additives are added to a mixture of the reaction product (A) and the polymerizable monomer (B), and solution polymerization is carried out. In this method, it is necessary to control the polymerization temperature within a range of 100°C or less.

At temperatures above 100°C, there is a high risk of gelation occurring during polymerization, making production practically impossible.

As the polymerization initiator, for example, peroxides, persulfates, azobis compounds, and redox systems in which these are combined with reducing agents can be used.

The organic solvent that can be used is not particularly limited, but hydrophilic organic solvents are preferred, such as alkyl alcohols such as methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, methyl carbitol, Examples include ether alcohols such as ethyl carbitol, and ether esters such as methyl cellosolve acetate and ethyl cellosolve acetate. In order to make the composition of the present invention aqueous, the carboxyl groups in the polymer may be partially or completely neutralized with a basic compound.

Basic compounds that can be used include monomethylamine,
monoethylamine, dimethylamine, diethylamine,
trimethylamine, triethylamine, monomethanolamine, dimethanolamine, trimethanolamine,
Examples include amines such as dimethylaminoethanol, and inorganic basic compounds such as caustic soda and caustic potassium.

The solids content of the aqueous dispersion from the aqueous dispersion composition produced in the present invention can be up to about 80% by weight, but from the viewpoint of quality and productivity, the solids content is preferably 15 to 50% by weight.

The aqueous dispersion composition obtained as described above can be prepared by adding a compound having a primary or secondary amino group, such as a polyalkylene polyamine and its adduct, a polyamide polyamine, a polysulfide resin, an amino resin, or a phenolic resin. By drying and heating if necessary, a film having a crosslinked network structure and excellent water resistance, heat resistance, and adhesiveness can be formed.

The aqueous dispersion composition produced by the present invention takes advantage of the excellent properties of the film obtained from this composition, and can be used in a wide range of applications, including paints for steel plates and wood such as cans, adhesives, paper, and binders for nonwoven fabrics. It can be used for various purposes.

The present invention will be specifically explained below using Examples.

In the examples, parts and % indicate parts by weight and % by weight. Reference Example 1 [Synthesis of polymerizable epoxy group-containing compound A] Bisphenol A type epoxy resin A. having an epoxy equivalent of 950. E
．． R. -664 (product name: manufactured by Asahi Kasei Corporation) 190 copies (0.
1 mol) was dissolved in 200 parts of ethyl cellosolve, and Na
OHO. Add 2 parts of O along with a small amount of water and raise the temperature to 120°C.

4.3 parts (0.05 mol) of methacrylic acid was added to this for about 2 hours, and the temperature was kept at 120-130°C until the acid value was 0.
．． The reaction is terminated when the value becomes 5 or less. The resulting compound contains 45 mol% of monoacrylate and 2.0% of diacrylate.
The ratio was 5 mol % and diepoxy 52.5 mol %.
This is called a polymerizable epoxy group-containing compound A. Reference example
2 [Polymerizable epoxy group-containing compound B. C,. Synthesis of D] 0.43 parts (0.43 parts) of the methacrylic acid used in Reference Example 1
005 mol), 0.86 part (0.01 mol) and 8.6
Part (0.1 mol) of polymerizable epoxy group-containing compound B
．． C and D were obtained.

Table 1 shows the ratio of each component. Reference Example 3 [Synthesis of polymerizable epoxy group-containing compound E] Instead of the epoxy resin used in Reference Example 1, an epoxy equivalent of 2700
Bisphenol A type epoxy resin A. E. R. -66
Polymerizable epoxy group-containing compound E was obtained in the same manner as in Reference Example 1, except that 540 parts (0.1 mol) of 9 (trade name; manufactured by Asahi Kasei Corporation) was used.

The ratio of the obtained compounds was 43.5 mol% monoacrylate, 5 mol% diacrylate, and 51.5 mol% diepoxy. 1. Prepare a polymerizable monomer mixed solution as follows.

Add polymerizable epoxy group-containing compound A solution 394 to this solution.
．． Add 3 parts and mix evenly. 100 parts of the mixed solution was put into a reactor and the temperature was raised to 80°C. The remaining liquid mixture was added dropwise over about 4 hours, the temperature was controlled at 80-90°C, and the reaction was continued for a total of 8 hours to obtain a viscous solution. After adding 10 parts of dimethylaminoethanol to this solution and mixing uniformly, 466 parts of demineralized water was added dropwise over about 1 hour. The obtained aqueous dispersion was stable at 40° C. for one month and had the following properties. PH-6.5
, viscosity 400 cps (Bruck Field viscometer) This aqueous dispersion was coated on an aluminum plate with a bar coater to a dry film thickness of 8 to 10 microns, and baked in a dryer set at 200°C for about 2 minutes. Ta.

The properties of the resulting coating film were as follows. Example 2
~9 A mixed solution of polymerizable monomers was prepared as shown in Table 2.

394.3 parts of polymerizable epoxy group-containing compound A solution is added to the polymerizable monomer solution shown in Table 2 and mixed uniformly.

Claims (1)

[Claims] 1(A) A bisphenol A epoxy resin having an epoxy equivalent of 900 to 4,000 and methacrylic acid in a ratio of 1/0.1 to 1
Compounds 10 to 9 obtained by reacting at a molar ratio of /0.5
0 parts by weight and (B) (a) acrylic acid or methacrylic acid 2
0 to 80% by weight (b) Aromatic vinyl monomer 10 to 60% by weight (c) α
・90 to 10 parts by weight of a polymerizable monomer consisting of 5 to 50% by weight of an alkyl ester of β-ethylenically unsaturated carboxylic acid are substantially uniformly mixed and polymerized at a temperature of 100°C or less to form a basic compound. A method for producing an aqueous dispersion composition, which is obtained by partially or completely neutralizing the composition.