JPS591756B2 - Suikeihifukusseibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to coating compositions comprising water-dispersed polymers.

Conventionally, amino-alkyd resin paints and amino-acrylic resin paints have been mainly used as baking paints for metals, and acid-catalyzed curing amino-alkyd resin paints have been mainly used for wood coatings. Since organic solvents are used for dilution, there are many drawbacks such as the impact of work, the risk of fire, and the problem of exhaust pollution, and improvements to these problems have been desired.

As a solution to these problems, the use of water-soluble polymers may be considered, but in many cases the resin concentration is insufficient and there are problems with the finish and durability. It is also known to polymerize a polymerizable monomer in an aqueous medium in the presence of an emulsifier or a protective colloid to obtain a stable water-dispersed polymer, which is then used as a coating composition. The dry film obtained from the aqueous dispersion coating composition produced by this method generally does not have a high degree of durability due to the emulsifier and the like. That is, the emulsifier is very hydrophilic and has a low molecular weight, and sodium polyacrylate, which is commonly used as a thickener,
Although polyacrylamide, polyvinyl alcohol, hydroxyethyl cellulose, etc. are polymers, they are not durable at all even when used as a film on their own, and the thickeners, etc. usually account for at most 10% by weight or less of the total non-volatile matter of the aqueous dispersion. 1
5% by weight, it was not possible to obtain films with excellent performance from conventional water-dispersible coating compositions.
The purpose of the present invention is to provide coatings that do not contain low-molecular emulsifiers and are stably dispersed in water or water-water-miscible organic solvent mixture systems, which are mainly composed of amino-alkyd-acrylic resins with low viscosity and high resin concentration. An object of the present invention is to provide a composition.

Another object of the present invention is to provide a coating material which is stable at room temperature and quickly cures when heated or in the presence of an acidic catalyst, exhibiting excellent hardness, weather resistance, stain resistance, impact resistance and water resistance. An object of the present invention is to provide a water-dispersed coating composition.

The above purpose is to obtain a solid content of 15 to 60 parts by weight of a water-soluble amino resin dissolved in water or a mixed system of water and a water-miscible organic solvent, and a solid content of an alkyd resin with an acid value of 25 to 150 dissolved in a water-miscible organic solvent. 5 to 60 parts by weight, pH 3.5
7.0 and a temperature of 60 to 1200C and neutralized, and the solid content of the water-soluble reaction main component having a solid content concentration of 8 to 60% by weight is 30 to 60 parts by weight. By a coating composition consisting of a water-dispersed polymer obtained by polymerizing 40 to 70 parts by weight of a single saturated monomer or a mixture of two or more saturated monomers with a polymerization initiator in the presence of the above water-soluble reaction main component. achieved.

As described above, the characteristic of the coating composition of the present invention is that the monomer is polymerized in the presence of a reaction product of a water-soluble amino resin and a high acid value alkyd resin, which exhibits sufficient durability even when formed into a coating itself. The point is that it is composed of a water-dispersed polymer obtained by

The water-soluble reaction product used in the present invention is water-miscible with a solid content of 15 to 60 parts, preferably 20 to 40 parts by weight, of a water-soluble amino resin dissolved in water or a mixed system of water and a water-miscible organic solvent. High acid value alkyd resin solid content dissolved in organic solvent 5
-60 parts, preferably 10-40 parts by weight of P
H3.5-3.7 (preferably 4.5-6.0) 60-
It is a reaction product having a solid content concentration of 8 to 60% by weight obtained by reacting and neutralizing at 12'C (preferably 80 to 1100C).

This reaction product is crosslinked between the methylol group of the amino resin and the carboxyl group or hydroxyl group of the alkyd resin, and then a neutralizing agent (e.g. ammonia, primary, secondary, tertiary alkyl amine, primary, secondary and tertiary oxyamines). In the present invention, the water-soluble reaction product is an essential component in order to obtain emulsification of the polymerizable monomer or good dispersion of the polymer. particles cannot be obtained, and even if particles are obtained, separation and aggregation are likely to occur.

The water-soluble amino resin can be obtained by condensing or co-condensing formaldehyde with melamine, benzoguanamine, triazine compounds, urea, diethylene urea, dicyandiamide, etc., using a conventional method. Also used are those modified with a modifier. Usually, 0.5 to 2.0 equivalents of formaldehyde are added to one equivalent of amino group as a pH regulator (e.g., sodium hydroxide, sodium carbonate, ammonia, primary, secondary, tertiary alkylamines, primary,
The reaction is carried out using a known method in alkaline or acidic conditions using secondary and tertiary oxyamines, hydrochloric acid, phosphoric acid, oxalic acid, and phthalic acid. Modifiers are mainly used to improve water solubility, storage stability, flexibility, and dispersion stability, such as (1
) Tetraethylenepentamine as a basic acid nitrogen derivative,
Guanylurea, guanidine carbonate, diethanolamine,
Ethylenediamine, etc. (11? Sodium sulfite and sodium hydrogen sulfite (Ill) as monohydric alcohols, alcohols with carbon atoms of 1 to 4 CiV), glycols, alkyl monoethers with 1 to 4 carbon atoms of diglycol () polyhydric Alcohols such as ethylene glycol, glycerin, and trimethylolpropane (D phenols (Vll); carboxylic acids such as formic acid, acetic acid, and fatty acids are used alone or in combination of two or more. On the other hand, the alkyd resin used It is obtained in the same manner as known solvent-diluted alkyd resins, and preferably has an acid value of 25 to 150, an OH value of 55 to 220, and an oil length of 0 to 50.Ethylene glycol, propylene as a polyhydric alcohol component Glycol, diethylene glycol, butylene glycol, 2-2-dimethylpropanediol, glycerin, trimethylolethane, trimethylolpropane, 1, 2, 6 hexanetriol, pentaerythritol, sorbitol, diglycerol, dipentaerythritol, etc., polybasic acid components Examples include phthalic anhydride, isophthalic acid, trimellitic acid, tetrahydrophthalic anhydride, maleic anhydride, fumaric acid, succinic acid, adipic acid, sebacic acid, etc. Also, as an oil component for modification or as a monobasic acid, drying oil , semi-drying oils, etc. can be used, and as monobasic acids, fatty acids obtained from these drying oils and semi-drying products, benzoic acid, p-tert-butylbenzoic acid, etc. can be used alone or in combination of several kinds. In the present invention, in order to improve the water-soluble reaction product and obtain a water-dispersed polymer having a high degree of film durability, the present invention further provides for monopolization using a polymerization initiator in the presence of the water-soluble reaction product. The monomer used is a single or a mixture of two or more ethylenically unsaturated monomers.

Not only water-insoluble materials but also water-soluble materials can be used. For example, acrylic acid, methacrylic acid,
Unsaturated carboxylic acids such as maleic acid, itaconic acid, crotonic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-monobutyl acrylate, 2-ethylhexyl acrylate , acrylic esters such as dodecyl acrylate, cetyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n- methacrylate
Methacrylic acid esters such as butyl, tert-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, cetyl methacrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate, styrene monomers such as styrene, vinyltoluene, and α-methylstyrene. vinyl acetate, vinyl propionate, acrylamide methacrylamide, acrylonitrile, vinyl stearate, divinylbenzene, diisopropenylbenzene, allyl acetate, diallyl adipate, dimethyl itaconate, diethyl maleate, acrylic alcohol, vinyl chloride, vinylidene chloride , styrene, etc. Among the above monomers, when using a monomer containing at least a part of a monomer having a group that can react with the methylol group of the amino resin, such as a carboxyl group, a hydroxyl group, or an amide group, the alkyd resin In addition to copolymerization between the fatty acid double bonds and the polymerizable monomer, crosslinking occurs between the reaction product and a portion of the polymer.

For this reason, the resulting water-dispersed polymer is a combination of a polymer obtained by polymerization of monomers and a water-soluble amino resin, compared to a simple mixture of a water-soluble amino resin and an alkyd resin or a conventional water-dispersed polymer. Even if they are difficult to miscible, they will not separate, and therefore the stability of the aqueous dispersion can be maintained well. The monomer is used in an amount of 40 to 70 parts by weight based on 30 to 60 parts by weight of the solid content of the water-soluble reaction product having a solid content of 8 to 60% by weight.

If the amount of monomer is less than 40 parts, the effect of improving the water-soluble reaction product will be small, and if it exceeds 70 parts, the stability of the resulting dispersion will decrease and separation and aggregation will easily occur. A solid content concentration of 8 to 60% by weight of the water-soluble reaction product is necessary to obtain fine particles of the polymer, and it is difficult to obtain fine particles outside this range. The water-dispersed polymer composition of the present invention uses a polymerization initiator as an emulsifying and dispersing stabilizer in the presence of the water-soluble reaction product,
It can be obtained by polymerizing a polymerizable monomer by a known emulsion polymerization or suspension polymerization method, and emulsion polymerization is particularly preferred.

In the case of these polymerization methods, the reaction medium is water in which a water-soluble reaction product is dissolved, or water and a water-miscible organic solvent (for example, methyl alcohol, ethyl alcohol, propyl alcohol, n-propyl alcohol, tert-butyl alcohol, ethylene Glycol, glycerin, diglycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mosobutyl ether, etc.) are used. Polymerization initiators include conventional inorganic peroxide compounds such as potassium or ammonium persulfate, hydrogen peroxide, percarbonates, acyl peroxides (e.g. benzoyl peroxide), alkyl hydroperoxides (e.g. tertiary butyl hydroperoxide, p-menthane hydroperoxide), dialkyl peroxide (e.g. ditertiary butyl peroxide)
Organic peroxide compounds such as are used. Inorganic and organic peroxide compounds can also be used as redox catalysts in combination with reducing agents. Examples of the reducing agent include sodium sulfite and sodium acid sulfite.
The polymerization temperature and the amount and type of polymerization initiator are appropriately selected depending on the reaction medium, but generally the polymerization temperature is 40°C.
~130℃, polymerization initiator is 0.5~4,
5% by weight is used.

The aqueous dispersion thus obtained does not contain low-molecular emulsifiers,
Moreover, since the molecular weight of the resin is large and the resin concentration is high, the water resistance and physical properties of the film are superior to those of conventional water-soluble resins alone or water dispersions obtained by emulsion polymerization of polymerizable monomers. The aqueous dispersion coating composition of the present invention can be dispersed in water or a mixed system of water and a water-miscible organic solvent, can be easily diluted with water or a water-miscible organic solvent, is stable at room temperature, and cures quickly by heating. As a coating, it has excellent hardness, weather resistance,
Shows stain resistance, adhesion, impact resistance, and water resistance.

The coating composition of the present invention is useful as a coating agent and is used as a finishing agent for steel plates, aluminum, zinc, copper, wood (including plywood), slate, and the like.

The coating composition can be applied by conventional coating methods such as brush coating, spray coating, electrostatic coating, flow coating, and roll coating. In addition to being used as a transparent coating, the coating composition can also contain pigments, dyes, zinc, aluminum,
It can also be used as a color toning coating containing a filler such as copper. Examples of the present invention will be described.

Example 1 Weighed 85 y of water, 419 g of melamine, 86 g of 80% paraformaldehyde, and 71 ethylene diamine into a 4-tube flask equipped with a stirring bar, a thermometer, a reflux condenser, and a dropping load (inner capacity: 1000 m0), and heated to a reflux temperature (approximately 103°C). ) for 60 minutes.

During this time, approximately 459 g of water was removed from the reflux condenser tube, and 809 g of methanol was added to obtain a water-soluble amino resin (component A). In another reaction vessel, 25.69% of soybean oil, 9.39% of glycerin,
Weigh out 0.029 of sodium formate and heat it to 230-2400C.
Transesterification was carried out for 2 hours at
7.29, add 3g of xylene and 1800C to 210℃
to produce an alkyd resin with an acid value of 25.
The xylene is collected by volatilization and removed using ethyl cellosolve to obtain a product with a non-volatile content of 50%. Add 100g of this alkyd resin solution and about 59% of oxalic acid to the above amino resin and adjust the pH.
5. O and react at 90°C for 60 minutes. Triethylamine was added to pH 9. The temperature of the reaction system was lowered to 6°C, and the non-volatile content was about 44% (1539).
A water-soluble main reaction product was obtained. Next, while maintaining the temperature, 39% potassium persulfate dissolved in 2009% water was added, and a mixture of 20g of styrene, 80g of butyl acrylate, and 609% of 2-ethylhexyl methacrylate was added dropwise over 60 minutes from the dropwise loading. 6 at temperature
The reaction was carried out for 0 minutes, and the temperature of the system was further raised to 80° C., and the reaction was continued at this temperature for 120 minutes to obtain about 710 g of a dispersion polymer having a non-volatile content of 44% and a viscosity of 1-J (Cardner). Example 2 Weighed 35 g of dehydrated castor oil fatty acid, 12.59 g of maleic anhydride, and 11.5 f of glycerin into a 4-cap flask (inner capacity 300 m) equipped with a stirring bar, thermometer, and nitrogen inlet. C to produce an alkyd resin with an acid value of 90.

Dilute with monomethyl glycol to obtain 50% non-volatile content. 100 g of this alkyd resin solution was added to the prison component 2509 of Example 1, and the pH was adjusted to 59 with oxalic acid. 0 and reacted at 900C for 60 minutes. About 6 g of diethanolamine was added to readjust the pH to 9.0, and the temperature of the reaction system was cooled to 60° C. to obtain a water-soluble reaction product solution with a nonvolatile content of about 41% (1429). While maintaining this temperature, add 1 liter of water.
Add potassium persulfate 39 dissolved in 009, styrene 309, butyl acrylate 80f11 2-ethylhexyl methacrylate 601, acrylonitrile 109
The mixture of
``The temperature was raised to C and the reaction was continued for an additional 2 hours with a non-volatile content of 50.
8(f) Dispersion polymer with viscosity H-1 (cardner) about 63
Get 09. Comparative Example 1 Hitaloid 2464 (trade name manufactured by Hitachi Chemical Co., Ltd.,
Solvent solution of thermosetting acrylic resin) 70 parts by weight and Melan 2
030 parts by weight.

67 parts by weight of rutile titanium white was kneaded with 100 parts by weight of each resin of Examples 1 to 2 and Comparative Example 1 to obtain white enamel. Table 1 shows the properties of the coating film baked on a steel plate at 1400C for 40 minutes. Gloss, one price,
The impact test was based on JISK-5400.

Eriksen is JIS-B-J Mo V29, JIS-K-79
77 compliant. Boiling water resistance is boiling water (98°C)
It was dipped in water and observed for blistering, peeling, changes in gloss, etc. The stain resistance is determined by the stain resistance from lipstick being 2'C. RH7
The degree of contamination was observed after being left in a 5% environment for 24 hours.
10% NaOH was subjected to a spot test in an environment with 75% CRH.

As is clear from the above comparison table, the films obtained from the compositions of the present invention were superior to those obtained from conventional solvent-based compositions.

Claims (1)

[Claims] 1 15 to 60 parts by weight solid content of a water-soluble amino resin dissolved in water or a water-water-miscible organic solvent mixture system, and 5 to 60 parts by weight solid content of an alkyd resin with an acid value of 25 to 150 dissolved in a water-miscible organic solvent. 60 parts by weight, pH 3.5-7.0
and obtained by reacting and neutralizing at a temperature of 60 to 120°C,
To 30 to 60 parts by weight of the solid content of a water-soluble reaction product having a solid content concentration of 8 to 60% by weight, 40 to 70 parts by weight of the ethylenically unsaturated monomer alone or in a mixture of two or more of the above water-soluble monomers are added. A coating composition comprising a water-dispersed polymer obtained by polymerization with a polymerization initiator in the presence of a reaction product.