JPS5928219B2 - thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to water-dilutable thermosetting aminoacrylic resin compositions that form coatings of excellent performance.

In recent years, the problem of pollution has been attracting a lot of attention.
In the field of paints, various studies have been made, such as replacing paints with water-based paints, powder paints, and non-photochemically active solvents. Among them, research on water-based paints is the oldest and is already being used in various fields. Conventional resins for water-based paints are mainly amine-neutralized. In this case, the amines used for amine neutralization, that is, for making the resin water-soluble, are often highly volatile and are generally harmful to the human body, so a water-based resin that does not use amines is desired. Therefore, as a result of intensive studies on non-amine neutralized water-soluble acrylic polymers and their curing systems, we have discovered the resin composition of the present invention that is water-dilutable without using an amine. That is, the present invention provides (
1) Acrylamide and/or methacrylamide 30~
60% by weight (hereinafter expressed in %), 30-60% of methyl acrylate and/or ethyl acrylate, 5-40% of monoesters of saturated aliphatic polyhydric alcohols of acrylic acid and/or methacrylic acid, and (meth)acrylic acid. ester of a saturated aliphatic monoalcohol, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, styrene, vinyltoluene, dialkylaminoethyl methacrylate, and 0 to 30% of a vinyl monomer other than the above. 30 to 90 parts by weight of acrylic polymer (hereinafter simply expressed in parts),
(2) Has two or more hydroxyl groups in the molecule and has a molecular weight of 200
A thermosetting resin composition comprising 0.3 to 30 parts of the above water-soluble reactive plasticizer and (3) 9 to 60 parts of water-soluble aminoblast. If the amount of the first component (meth)acrylamide used, which is the raw material for the acrylic polymer, is less than 30%, the water solubility of the polymer will be poor, and if diluted with water, the polymer will precipitate. If it exceeds 60%, the water solubility of the polymer is excellent, but the cured coating film of the composition has poor water resistance, which is inappropriate.

Therefore, usually 30-60%, preferably 35-50%
is within the range of In the case of other raw materials, methyl acrylate and ethyl acrylate, if the amount used is less than 30%, the water resistance of the cured coating will be poor, and if it exceeds 60%, the water dilutability of the polymer will be poor. Usually 30-60% preferably 40%
~55% range. Other raw materials that can be used as monoesters of saturated aliphatic polyhydric alcohols of (meth)acrylic acid include, for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
Included are polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, and the like. These monoesters are used to introduce into the acrylic polymer functional groups that participate in the network structure formation reaction with the aminoplast during heat curing, and if the amount used is less than 5%, the coating film will not be sufficiently cured. Performance will deteriorate, and if it exceeds 40%, water resistance will deteriorate.
It is usually in the range of 5 to 40%, preferably 10 to 30%. Other vinyl monomers of the present invention other than those mentioned above include 0 to
Esters of saturated aliphatic monoalcohols of (meth)acrylic acid, excluding methyl acrylate, ethyl acrylate, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, styrene, vinyltoluene, dialkylaminoethyl Selected from methacrylate.

Examples of esters of saturated aliphatic monoalcohols of acrylic acid that can be used include methyl methacrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, pentyl acrylate, 2-ethylhexyl acrylate, lauryl. Acrylate, stearyl acrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate,
Examples include isobutyl methacrylate, t-butyl methacrylate, pentyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, and stearyl methacrylate. Examples of dialkylaminoethyl methacrylates that can be used include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like. A water-soluble acrylic polymer, which is a component of the composition of the present invention, can be produced by solution polymerizing the raw materials having the above composition.

As a polymerization solvent, 100% water is desirable from the viewpoint of non-polluting properties, but this does not provide sufficient water dilutability and sufficient transparency of the polymer solution. However, a mixture of a less toxic alcohol such as ethyl alcohol, isopropyl alcohol, etc., and water is suitable. Isopropyl alcohol is particularly preferred because it is effective as a chain transfer agent for acrylic polymers and is useful for adjusting the molecular weight. The mixing ratio of the alcohol and water is 5/95 to 30/70, preferably 10 in view of transparency of the polymer solution, water dilutability, pollution, etc.
The range is from /90 to 30/70. As a polymerization initiator, water-soluble persulfates such as potassium persulfate, sodium persulfate,
Particularly preferred is ammonium persulfate. If the amount used is less than 0.5 parts per 100 parts of the polymerizable monomer, the molecular weight will be too large and water dilutability will be poor, and if it exceeds 10 parts, the molecular weight will be too small and the coating performance will deteriorate. It is usually 0.5 to 10 parts, preferably 1 to 5 parts. The water-soluble reactive plasticizer, which is the second component of the composition of the present invention, has two or more hydroxyl groups in its molecule, is water-soluble, and is a compound with a molecular weight of 200 or more.

In addition to the conditions specified above, such compounds must also be compatible as a water-soluble reactive plasticizer. Regarding compatibility, it is important to add it to a mixture of a water-soluble acrylic polymer and a water-soluble aminoplast to form a paint, and the coating film that is applied and baked becomes transparent. Moreover, since such a plasticizer has two or more hydroxyl groups, it crosslinks with the aminoplast to form a network structure. The molecular weight is set at 20 to prevent performance deterioration due to its use.
Must be 0 or more. If the molecular weight is less than 200, the water resistance of the cured coating film will be poor. Since the above-mentioned reactive plasticizer is used primarily to improve flexibility, it is usually used by mixing it with the produced acrylic polymer. However, it is also possible to produce an acrylic polymer by polymerizing in the presence of the above-mentioned reactive plasticizer. In this case, there is an advantage that the transparency of the polymer solution is improved compared to simple mixing.
The reason for this is not clear, but it is thought to be due to the generation of a very small amount of graft. Examples of such water-soluble reactive plasticizers include polyethers, polyvinyl alcohols, polysaccharides, methyl cellulose, and glycidyl ethers. Examples of polyethers include polyethylene glycol, polypropylene glycol, ethylene oxide or propylene oxide adducts of trimethylolpropane, and ethylene oxide or propylene oxide adducts of pentaerythritol. Examples of polyvinyl alcohol include P manufactured by Kurashiki Rayon Co., Ltd.
VA-205, 217, 2101117, 105, Gohsenol NL-105, NM-11 manufactured by Nippon Gosei Co., Ltd.
, NM-14, NH-17, GL-05, GL-03,
Average degree of polymerization 30, roughly represented by GM-14, GMl7, etc.
A number between 0 and 2000 is appropriate. Polysaccharides include glucose mannose and galactose. Glycidyl ethers include polypropylene glycol glycidyl ether, polyethylene glycol glycidyl ether,
Examples include glycerin diglycidyl ether and sorbitol glycidyl ether. The water-soluble aminoplast, which is the third component of the composition of the present invention, acts as a crosslinking component for the water-soluble acrylic polymer. As the aminoplast, water-soluble etherified types such as methyl, ethyl, and isopropyl can be used, but the methyl etherified type is preferred from the viewpoint of essential water solubility and versatility. As the water-soluble aminoplast, generally available commercially available water-soluble aminoplasts can be used. That is, in the case of methylolated one or a mixture of two or more of melanin, urea, benzoguanamine, etc., and partially etherified with methyl alcohol, ethyl alcohol, isopropyl alcohol, etc., and methyl alcohol, substantially no methylol group is present. It also includes things that have been completely etherified until they are gone. Moreover, these cocondensates can also be used. The composition of the present invention comprises 30 to 90 parts of the water-soluble acrylic polymer described above, 0.3 to 30 parts of a water-soluble reactive plasticizer, preferably 1 to 20 parts, and 9 to 60 parts of a water-soluble aminoplast. be.

The desirable ratio of the water-soluble aminoplast to the acrylic polymer is 9:1 to 7:3 in terms of solid content when the composition of the present invention is used for high temperature baking, and 7:3 when the composition is used for acid curing at low temperatures. It is in the range of 3 to 4:6. Such a composition is 60
By baking at ~300℃, gloss, texture, chemical performance,
Since it forms a coating film with excellent physical properties, it is particularly useful for clear paints or enamel paints containing pigments. There are no restrictions on the materials to be coated, including metal, wood,
It can be applied to any material such as plastics. In particular, when used for woodworking, an acid curing method in which an acid catalyst (hydrochloric acid, para-toluenesulfonic acid, etc.) is used in combination and heating is performed at 60 to 100°C for 5 to 20 minutes is desirable. Various coating methods such as spray coating and roller coating are possible. The present invention will be explained below with reference to Examples.

Example 1 22.6 parts of isopropyl alcohol, 53.8 parts of water, Hybrox RQ-500 (Dainippon Co., Ltd.) were added to a reactor equipped with a thermometer, condenser, stirring bar, inert gas inlet pipe, and dropping load in a N2 gas stream. 10 parts of propylene oxide adduct of polyhydric alcohol (manufactured by Ink Kagaku Kogyo Co., Ltd.) were charged, and the temperature was raised to 80°C in an oil bath constant temperature bath.

Then, in a solution prepared by dissolving 40 parts of acrylamide in 26.6 parts of water, 39 parts of methyl acrylate, 10 parts of ethyl acrylate, and 1 part of 2-hydroxyethyl methacrylate were added.
Monomer mixture 12 with 0 parts and 1 part of methacrylic acid added
6.6 parts and 13 parts of a catalyst solution prepared by dissolving 3 parts of ammonium persulfate in 10 parts of water were added dropwise in parallel to the reaction system over a period of 2 hours. The reaction temperature at this time was maintained at 80 to 85°C by refluxing the isopropyl alcohol. Thereafter, the mixture was kept at the same temperature for another 2 hours to obtain an acrylic polymer solution having a nonvolatile content of 50.5%, a viscosity W (Gard viscosity), and an acid value of 10.2. Water zone S- is applied to the obtained acrylic polymer solution.
616 (manufactured by Dainippon Ink & Chemicals, water-soluble methyl etherified melamine resin) was mixed at a resin solid content ratio of 60:40. Furthermore, as an acid catalyst, concentrated hydrochloric acid/P-toluenesulfonic acid/water/isopropyl alcohol-20/20/
A solution of 45.44/14.56 (weight ratio) was added at 20% by weight based on the solid content of the mixed resin, and a diluent of water/isopropyl alcohol: 80/20 (volume ratio) was added to make black 4. Adjusted to 35 seconds using a food cup. Approximately 45 f of this paint was applied to paper-covered printed plywood! Roll coating was performed in /A, and baking was performed at 80°C for 10 minutes in a hot air dryer. This coating had excellent performance as shown in Table 1. Example 2 Into the same apparatus as in Example 1, 21.6 parts of isopropyl alcohol, 53.3 parts of water, and 5 parts of polyvinyl alcohol Gohsenol GL-05 (manufactured by Nippon Gosei Kagaku, polyvinyl alcohol) were charged, and the mixture was heated in an oil bath constant temperature bath. The temperature was raised to 80°C.

Then, in a solution in which 35 parts of acrylamide was dissolved in 23.3 parts of water in advance, 35 parts of methyl acrylate, 10 parts of ethyl acrylate, 2
Monomer mixture 123 with 0 parts and 10 parts of vinyl acetate added
．． 3 parts and 13 parts of the previously mentioned catalyst solution were added and copolymerized in the same manner as in Example 1, resulting in a non-volatile content of 50.3% and a viscosity of
An acrylic polymer solution with Y and an acid value of 11.8 was obtained. The same water-soluble melanin resin as in Example 1 was mixed with this in the same proportion,
Hereinafter, the same treatment as in Example 1 was performed. This coating had excellent performance as shown in Table 1. Example 3 In the production of the water-soluble acrylic polymer in Example 1, methacrylic acid was not used at all, and 40% of methyl acrylate was used.
Same procedure except that 50.3% non-volatile content was used,
An acrylic polymer solution having a viscosity of v and an acid value of 6.8 was obtained.

A coating film obtained using the same in the same manner as in Example 1 had excellent performance as shown in Table 1. Comparative Example 1 In the same apparatus as in Example 1, 20.6 g of isopropyl alcohol was added.
The temperature was raised to 80°C in an oil bath constant temperature bath, and 126.6 parts of the same monomer mixture as in Example 1 and 13 parts of the previously described catalyst solution were added dropwise to the mixture. Copolymerized in the same manner as 1 to obtain a non-volatile content of 50.7%, viscosity Y,
A polymer solution having an acid value of 11.0 was obtained.

This was mixed with the same water-soluble melamine resin as in Example 1 in the same proportion, and the same treatment as in Example 1 was carried out. This coating film was poor in texture, adhesion, crack resistance, etc. Comparative Example 2 Commercially available amine-neutralized alkyd resin-A (non-volatile content 50%
) and water sol S-616 (already mentioned) at a solid content ratio of 20.
Weight% blended, water/isopropyl alcohol = 80/2
Add 0 (volume ratio) of diluent and add 3 with 4 black food cups.
Approximately 4 coats of paint adjusted for 5 seconds to paper-bound printed plywood
It was roll coated at 57/wl and baked in a hot air dryer at 80°C for 10 minutes.

This coating film was inferior in terms of texture, water resistance, solvent resistance, blocking resistance, hardness, drying property, moist heat resistance, etc. Comparative Example 3 A commercially available acrylic emulsion 1B (non-volatile content 50%) was mixed with Watersol S-616 (previously listed) at a solid content of 30% by weight, water was added, and the paint was adjusted to 35 seconds using a black 4 food cup. A baked coating film was produced under the same conditions as in Example 1.

Claims (1)

[Claims] 1 (1) Acrylamide and/or methacrylamide 3
0 to 60% by weight, 30 to 60% by weight of methyl acrylate and/or ethyl acrylate, 5 to 60% of monoester of acrylic acid and/or methacrylic acid and saturated aliphatic polyhydric alcohol
40% by weight and esters of saturated aliphatic monoalcohols of (meth)acrylic acid, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, styrene, vinyltoluene, dialkylaminoethyl methacrylate other than the above. 30-90 parts by weight of a water-soluble acrylic polymer consisting of 0-30% by weight of monomers, (2) 0.3 parts by weight of a water-soluble reactive plasticizer having two or more hydroxyl groups in the molecule and having a molecular weight of 200 or more. 30 parts by weight and (3) 9 to 60 parts by weight of a water-soluble aminoplast.