JPS6027699B2 - Thermosetting coating material - Google Patents

Description

Detailed Description of the Invention The present invention is based on the general formula (R is CH3, at least one of R and R3 is a lower alkyl group, a lower hydroxyalkyl group, or a lower hydroxyalkyl group esterified with a fatty acid) A copolymer of an unsaturated oxazoline having a substituent at the 4-position of the oxazoline structure represented by Q,8-monoethylene unsaturated carboxylic acid and other copolymerizable monomers was melted or dispersed in a medium. This invention relates to thermosetting coating materials.

Conventionally, various types of thermosetting coating materials have been put into practical use as coating materials that can form coatings with excellent appearance, mechanical properties, chemical resistance, and weather resistance. Coating materials used as crosslinking reactive groups are attracting attention as they exhibit unique properties.

As such a coating material, for example, a composition in which a bis- or trisoxazoline compound is blended with a polycarboxylic acid copolymer has been reported, and a crosslinked coating film formed from this coating material has a relatively good practical use. However, the crosslinking density is not sufficient, and it is desired to further improve the above properties.

Therefore, the present inventors are currently considering a method using vinyloxazoline, and while vinyloxazoline without a substituent has poor polymerization stability, when a specific vinyloxazoline represented by the above formula is used, found that the weight stability was good, but the polyvinyloxazoline obtained from this method had the disadvantage of insufficient crosslinking reactivity during heating. Therefore, we made efforts to improve this drawback and found that when unsaturated carboxylic acid was used as a comonomer, the crosslinking reactivity was significantly improved and a coating material with excellent properties could be obtained.We completed the present invention. did. The gist of the present invention is that at least one of R, CH3, R2, and R3 is selected from a lower alkyl group, a hydroxy lower alkyl group, and a hydroxy lower alkyl group esterified with a fatty acid. It is something.

), monoethylenically unsaturated carboxylic acids 1 to 4 by weight, and other copolymerizable monomers 20 to 9 weight%, with a molecular weight of 3,000 to 40; 0
The first invention is a thermosetting coating material in which a paint containing a copolymer of No. 00 as a binder component is dissolved or dispersed in a medium.
The second invention is a thermosetting coating material prepared by dissolving or dispersing in a medium a coating material containing 3 to 5% by weight of a polyepoxy compound of 0.1 to 4000 as a binder component. A third invention is a thermosetting coating material in which a paint containing as a binder component an acidic curing catalyst of ~2% by weight is dissolved or dispersed in a medium,
Said copolymer 50-90% by weight, epoxy equivalent 90-4
000 polyepoxy compound in a proportion of 3 to 5% by weight and an acid curing catalyst in a proportion of 0.1 to 2% by weight relative to the copolymer as a binder component. A thermosetting type in which a paint is dissolved or dispersed in a medium. The fourth invention is a covering material.

The side chains of the copolymer contained in the coating composition of the present invention contain specific amounts of oxazoline groups and carboxyl groups as crosslinkable functional groups, and therefore the coating composition formed from the coating composition of the present invention The curing of the film mainly proceeds through an addition reaction between oxazoline groups and carboxyl groups.

Therefore, if the amount of oxazoline groups contained in this copolymer is small, a coating film that is insufficiently cured will be formed, and a large amount of surplus free carboxyl groups will remain, resulting in poor mechanical hardness and Properties, solvent resistance, etc. deteriorate. On the other hand, a coating film formed from a coating material made of a copolymer containing too many oxazoline groups is undesirable because the curing progresses too much, resulting in a hard coating film with low workability. Therefore,
The amount of unsaturated oxazurin copolymerized into the copolymer used in the present invention must be appropriately determined while taking into account the practical performance of the coating material, and the copolymer used in the present invention has a content of 1 to 4.
A copolymerization amount of 3% to 2% by weight is suitable. In addition, the amount of copolymerized monoethylenically unsaturated carboxylic acid in the above copolymer must be appropriately determined so that the best performance can be exhibited through the crosslinking reaction of the coating film formed by the coating material of the present invention. In the present invention,
It is preferable that the copolymer is copolymerized in the range of 1 to 4% by weight, preferably 3 to 3% by weight. Further, even within the above range, it is preferable that both monomers are combined and copolymerized so that the oxazoline group equivalent and carboxyl group equivalent are in a ratio of 1'0.5 to 1/3.

Specific examples of the unsaturated oxazoline compounds include 2-vinyl-4-methyl-2-oxazoline, 2-pinyl-4
-Ethyl-2-oxazoline, 2-vinyl-4,4'-dimethyl-2-oxazoline, 2-vinyl-4,4'-
Hydroxymethyl-2-oxazoline, 2-isobrobenyl-4-methyl-2-oxazoline, 2-isoprobenyl-4,4'-dimethyl-2-oxazoline, 2-isoprobenyl-4,4-dihydroxymethyl-2-oxazoline, 2-isoprobenyl- Examples include 4,4'acetylmethyl-2-oxazoline.

Examples of monoethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, monoesters of itaconic acid, hydroxyalkyl (meth)acrylates, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Specific examples include unsaturated carboxylic acids obtained by addition reaction with acids and acid anhydrides such as trimellitic anhydride.

Other copolymerizable monomers include alkyl esters or phenyl esters of acrylic acid or methacrylic acid, hydroxyalkyl esters of acrylic acid or methacrylic acid, glycidyl esters of acrylic acid or methacrylic acid, or Methylglycidyl ester acrylamide, methacrylamide, methylolacrylamide or methacrylamide, N-alkoxymethylacrylamide or methacrylamide, acrylonitrile, methacrylonitrile, styrene, vinyltoluene, vinyl acetate, vinyl propionate, other Z fatty acid vinyl esters, etc. can be mentioned. In order to maintain good properties such as weather resistance, stain resistance, and processability of the coating film formed from the coating material of the present invention, among other copolymerizable monomers, acrylic It is desirable that the copolymerized amount of the alkyl ester of acid or methacrylic acid is 1% by weight or more.

As a method for producing the copolymer used in the present invention, known polymerization methods such as bulk polymerization, emulsion polymerization, suspension polymerization, and solution polymerization can be used.

The molecular weight of the polymer used in the present invention is 3,000 to 40,0
00, preferably in the range of 4,000 to 20,000. Coating materials containing a copolymer with a molecular weight smaller than 3,000 as a binder component have poor mechanical properties and chemical properties. It is not possible to form a coating film with excellent coating properties including properties.

On the other hand, coating materials whose binder component is a copolymer with a molecular weight exceeding 40,000 will depend on its form, but if the form is in the form of a solution, its viscosity tends to be high, and its coating workability is This is undesirable, as the fluidity of the coating film during heating during coating film formation also decreases, making it difficult to form a coating film with excellent smoothness.

In addition, the coating material of the present invention forms a cured coating film by phosphorizing at a temperature of 150 to 250q0, but if it is necessary to bake at a lower temperature or for a shorter time, Lewis acid complex or paratoluene sulfone may be used. Acid-like hardening of 0.1
By adding it to the copolymer in a range of ~2% by weight,
The coating film can be effectively crosslinked and cured at low temperatures and in a short time.

The coating film made from the coating material of the present invention has excellent appearance and mechanical properties, but in order to further improve the water resistance and corrosion resistance of the coating film, it is necessary to The polyepoxy compound may be added in an amount of 5% by weight, preferably in the range 3-2% by weight.

Polyepoxy compounds that can be used include those having two or more epoxy groups in one molecule and having an epoxy equivalent of 90 to 4,000.
Polyepoxy compounds are preferred, and specific examples thereof include epoxy resins obtained by condensation of bisphenol A and epithalolhydrin or methylepichlorohydrin,
For example, commercially available products include Epicort #828 and #100.
1, #1004 top (manufactured by Shell Chemical Co., Ltd.) is available. Other epoxy compounds and di- or triglycidyl esters or methylglycidyl esters of polycarboxylic acids such as adipic acid, sebacic acid, isophthalic acid, terephthalic acid, trimellitic acid, triglycidyl isocyanurate,
Examples include pinylmicrohexene dioxide. (2) The polyepoxy compound has the effect of improving the dispersibility of the pigment in the binder when used as an enamel coating material using pigments, or the adhesion of the coating film formed from this coating material to the coated object. has. In the coating composition of the present invention, when the medium for the copolymer is an organic solvent, water, or a mixture thereof, the copolymer can be used as a solution or dispersed in such a medium. The coating material in this form can be applied to the object to be coated by a coating method such as spray coating, dipping, roll coater coating, or curtain coater coating.

Furthermore, when the dispersion medium for the copolymer is air, nitrogen gas, or other gas, the coating material of the present invention can be treated as a powder coating, and can be applied by electrostatic coating, fluidized coating, etc. can.

Further, these powder coatings can also be used as dispersion coatings in which they are dispersed in the above-mentioned liquid medium, and in this case, a polymer powder may also be used in the liquid medium. In addition, the above copolymer is unique. It can also be used as a covering material in the form of a film or sheet. When the coating material of the present invention is a powder coating, it is necessary to maintain a good balance between the blocking properties of the powdered polymer and the fluidity during heating and melting. 50 to 20,000, preferably 80 qo
~150 qo may be sufficient.

When a copolymer having such a melting point is used as a powder coating, a cured coating film with excellent appearance, mechanical properties, chemical resistance, tear resistance, etc. can be formed. Since the copolymer contained in the coating film of the present invention uses an unsaturated oxazoline with a specific structure as described above and an unsaturated carboxylic acid as starting materials, its polymerization stability is higher than that of other unsaturated oxazolines. This method is better than the method for producing the copolymer used as a starting material, and the storage stability of the obtained polymer is also good. Moreover, the balance between fluidity and crosslinking reactivity during heating is remarkable compared to other copolymers using vinyloxazoline as a starting material, or resin compositions made of polycarboxylic acid resin and bis or trisoxazoliso. The coating material of the present invention containing such a copolymer as a binder component can form a coating film with excellent coating performance. The coating film formed from the coating material of the present invention forms a cured coating film with excellent appearance, mechanical properties, film resistance, and chemical resistance by baking under baking conditions of 150 qo to 250 qo, so it is especially suitable for indoor use. It can be used for outdoor metal structures, household electrical appliances, steel furniture, automobile interior and exterior bags, and can also be used to protect glass, stone, and ceramics, or for decorative coating.

Hereinafter, the present invention will be explained in more detail with reference to Examples, in which all parts are by weight. Example 1 35 parts of methyl methacrylate, 47 parts of 2-ethylhexyl methacrylate, 11 parts of 2-isoprobenyl-4,4-dimethyl-2-oxazoline, and 7 parts of methacrylic acid were added in a total amount of 10 parts, and further low octyl A mixture of 2 parts of mercaptan and 0.3 parts of azobisisoputilonitrile was subjected to bulk polymerization at a temperature in the range of 70 to 80 oo to obtain an acrylic polymer having a molecular weight of about 13,000.

This polymer was powdered and electrostatically coated as a powder coating material on a polished mild steel plate with a thickness of 0.8 side, and baked at 200 ooox for 30 minutes. The gel fraction of the crosslinked coating film obtained was 96%.
Furthermore, a coating film with good surface smoothness and good adhesion was formed.

Further, even after the powdered coating material was left at room temperature for one month, almost no thickening phenomenon over time or blocking of the powder was observed.

Example 2 Methyl methacrylate 3 base, tridecyl methacrylate 5
2 parts, 11 parts of 2-isoprobenyl-4,4-dimethyl-2-oxazoline, and 7 parts of methacrylic acid for a total of 10 parts, and further 2 parts of n-octylmercaptan, and 0.0 parts of azobisisobutyronitrile. Bulk polymerization was carried out under the same conditions as in Example 11, and the molecular weight was about 11.0.
00 solid acrylic polymer was obtained.

This polymer 10 foundation'co-toluene sulfonic acid 0.5
The mixture was melted and kneaded at 100° C. or below, and then finely pulverized to obtain a powder of 200 mesh pass.

This powder was electrostatically applied as a powder coating to a polished mild steel plate with a thickness of 0.8 mm, and a competition was conducted under the conditions of 200℃ x 3 minutes, and a smooth coating film with an excellent appearance was formed. . The obtained film had a gel fraction of 97%, excellent solvent resistance, and good adhesion. Example 3 25 parts of methyl methacrylate, 5 parts of tridecyl methacrylate
6 parts of 2-isobrobenyl-4,4-dimethyl-2-oxazoline, 1 part of methacrylic acid in a total of 10 parts, 2 parts of n-octylmercaptan, 0.0 parts of azobisisoptylonitrile. Bulk polymerization was carried out under the same conditions as in Example 1 by adding $ parts, and the molecular weight was about 10.0.
00 polymer was obtained.

Next, 1 part of an epoxy resin (Epicote #1001 manufactured by Shell Co., Ltd.) was added to 100 parts of this polymer, melted and kneaded at 100 qo or less, and then ground to give a fine powder of 200 mesh pass. This powder coating was electrostatically applied to a polished mild steel plate having a thickness of 0.8 feet, and then subjected to a glazing under conditions of 200 to 220 mm x 30 minutes. The resulting coating film had a thickness of approximately 50 ridges, had a good hardness, an Erichsen value of 4 to 7, and had excellent xylene resistance, and had excellent adhesion and workability. Example 4 100 parts of the polymer produced in Example 3 and epoxy resin (
30 parts of EPICOAT #1001) (manufactured by Shell Chemical Co., Ltd.) was melt-kneaded for less than 100 minutes, and then finely pulverized to obtain a fine powder of 200 mesh pass.

This fine powder was used as a powder coating material, and a crosslinked coating film was prepared in the same manner as in Example 3. The resulting coating film had a good appearance, was glossy, had a hardness of 2H to fine, and an Excelin value of 3 to 5. Example 5 100 parts of the acrylic polymer obtained in Example 1 was dissolved in a mixed solvent of xylol/lobtanol=3/1 to prepare a 50% resin solution.

Add 50 parts of titanium oxide to this resin solution 10% to enamel it, dilute it with a solvent to a solid content concentration of 60%, spray paint it on a 0.8 side polished steel plate, and hold it at 200°C
I made the Akatsuki tsuki. The resulting coating film had good coating surface condition, good adhesion, and good xylene resistance. Example 6 3 parts of methyl methacrylate, 3 parts of n-phthyl methacrylate, 1 part of styrene, 2 parts of n-butyl acrylate, 3 parts of 2-vinyl-4-methyl-2-oxazoline,
5 parts of itaconic acid, 0.7 parts of n-othythyl mercaptan,
Azopisisobutyronitrile 0. Mix $ parts, 70~
Bulk polymerization was carried out at a temperature in the range of 80 o'clock, and the molecular weight was 20.
000 acrylic polymer was obtained.

This acrylic polymer is xylol/n-butanol=
It was dissolved in a 3/1 mixed solvent to create a resin solution with a solid content of 5% by weight. This solution was spray-painted on a 0.8-side polished steel plate, and abrasion was applied for 200q0 x 30 minutes. The resulting coating film had a good surface condition and was excellent in adhesion and solvent resistance. Example row 7 25 parts of styrene, 35 parts of 2-ethylhexyl acrylate, 2 parts of 2-isoprobenyl-4,4'-dihydroxymethyl-2-oxazoline, 20 parts of acrylic acid, 3 parts of n-octylmecaptan, azoisobutylene Tyronitrile 1.0
5 parts xylol/n-butanol = 3/1 mixed solvent
0 base part was dissolved and solution polymerized at 80°C to obtain a molecular weight of 7.
,000 copolymer solution was obtained.

This copolymer solution was spray-painted on a 0.8 rib polished mild steel plate, and glazing was performed at 200°C for 30 minutes. The resulting coating film had a good surface condition and had good adhesion and solvent resistance. In the present invention, the following measurement methods were used to evaluate the surface condition, adhesion, and solvent resistance of the painted surface.

1. Surface appearance: The smoothness, etc. of the coating film surface was evaluated with the naked eye.

2 Adhesion: Evaluation by Eriksen test method.

3. Solvent resistance: Evaluation by xylol 100 times rubbing test method.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ 1 to 40% by weight of monomers represented by hydroxy lower alkyl groups, 1 to 40% by weight of monoethylenically unsaturated carboxylic acids, and 20 to 98% of other copolymerizable monomers. Molecular weight in weight% 3,000-40,0
A thermosetting coating material made by dissolving or dispersing a paint containing a copolymer of No. 00 as a binder component in a medium. 2 The amount of copolymerization of the monomer represented by general formula [1] is 3 to 3.
2. The thermosetting coating material according to claim 1, wherein a copolymer containing 20% by weight is used as a binder component. 3 Claim 1 characterized in that a copolymer of the monomer represented by the general formula [1] and an unsaturated carboxylic acid in a copolymerization equivalent ratio of 2/1 to 1/3 is used as a binder. Thermosetting coating material as described in section. 4. The thermosetting coating material according to claim 1, wherein the coating material is in the form of a fine powder and a gas is used as a dispersion medium. 5 General formulas ▲ Numerical formulas, chemical formulas, tables, etc. ), monoethylenically unsaturated carboxylic acid 1-40% by weight, and other copolymerizable monomers 20-98% by weight. 000~40,0
00 copolymer 50-97% by weight and epoxy equivalent 90-90%
A thermosetting coating material in which a coating material containing 3 to 50% by weight of a polyepoxy compound of 4000 as a binder component is dissolved or dispersed in a medium. 6. The thermosetting coating material according to claim 5, characterized in that a polypoxy compound having an epoxy equivalent of 300 or more and a molecular weight of 500 or more is used. 7. The thermosetting coating material according to claim 5, wherein the paint is in the form of a fine powder and a gas is used as a dispersion medium. 8 General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is H, or CH_3, R_2, R_3 are at least one selected from a lower alkyl group, a hydroxy lower alkyl group, and a hydroxy lower alkyl group esterified with a fatty acid. ), monoethylenically unsaturated carboxylic acid 1-40% by weight, and other copolymerizable monomers 20-98% by weight. 000~40,0
A thermosetting coating material prepared by dissolving or dispersing in a medium a paint whose binder component is a copolymer of 0.00 and 0.1 to 2% by weight of an acidic curing catalyst. 9 The amount of copolymerization of the monomer represented by general formula [1] is 3 to 3.
The thermosetting coating material according to claim 3, characterized in that the copolymer is used in an amount of 20% by weight. 10 Claim 8, characterized in that a copolymer of the monomer represented by the general formula [1] and an unsaturated carboxylic acid with a copolymerization equivalent of 2/1 to 1/3 is used. Thermosetting coating material. 11. The thermosetting coating material according to claim 8, wherein the paint is in the form of a fine powder and a gas is used as a dispersion medium. 12 General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ), monoethylenically unsaturated carboxylic acid 1-40% by weight, and other copolymerizable monomers 20-98% by weight. 000~40,0
00 copolymer 50-97% by weight, epoxy equivalent 90-90%
4000 polyexy compound in a proportion of 3 to 50% by weight and an oxidation curing catalyst in a proportion of 0.1 to 2% by weight relative to the above copolymer as a binder component. A thermosetting method in which a paint is dissolved or dispersed in a medium. Mold covering material. 13 The amount of copolymerization of the monomer represented by general formula [1] is 3
13. The thermosetting coating material according to claim 12, characterized in that the copolymer is used in an amount of 20% by weight. 14 Claim 12, characterized in that a copolymer of the monomer represented by the general formula [1] and the unsaturated carboxylic acid is used in a copolymerization equivalent ratio of 2/1 to 1/3. thermosetting coating material. 15. The thermosetting coating material according to claim 12, wherein the coating material is in the form of a fine powder and a gas is used as a dispersion medium.