JPH0425577A - Thermosetting covering composition excellent in adhesiveness and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermosetting coating composition with excellent adhesive properties and a method for producing the same.

(Prior art) Generally, methacrylic resins containing methyl methacrylate as the main component are used in lighting covers, automobile parts, signboards, decorative items, etc. due to their excellent weather resistance, transparency, and appearance that exceeds 400 mm.
It is used in various fields such as miscellaneous goods, and because it can be expected to have a good appearance finish such as excellent surface properties, it is also used in various fields to coat the surfaces of various different resins with methacrylic resin. It is being done. Conventionally, various methods have been proposed for performing these coating treatments.
For example, (a) after impregnating syrup made of methyl methacrylate monomer and its linear polymer, heating and
Method for obtaining coated molded products by compression (Japanese Patent Application Laid-open No. 49-9480
4), (b) A method of laminating a sheet-formed methacrylic resin on a decorative sheet under heat and pressure to obtain a coated molded product (JP-A-47-11396), (C) Film-formed methacrylic resin Examples include a method in which a coated article is obtained by bringing a resin into contact with the surface of a monopolymer containing a polymerizable monomer and a solvent, and then heating and curing the uncured product (Japanese Patent Application Laid-open No. 135122/1983).

[Problems to be Solved by the Invention] However, since the methacrylic resin is a linear polymer, it has the drawback that the heat resistance, solvent resistance, etc. of the surface of the coated article are insufficient.

In addition, (a) the method of impregnating syrup has excellent adhesive properties, but it has problems such as making it difficult to thicken the coating layer and requiring many steps, while (b) The method of using sheet-like or (C) film-like methacrylic resin is complicated because it has to be processed in advance into various sheet or film forms depending on the thickness of the coating layer, matte appearance, etc., and it is difficult to obtain sufficient adhesion. There were some problems, such as people not being satisfied.

Therefore, in order to solve the above-mentioned problems, it is an object of the present invention to provide a coating composition that has permeability and fluidity comparable to that of syrup, is easy to handle, and a method for manufacturing the same, and further has heat resistance and fluidity. It is an object of the present invention to provide a coating composition that can form a coating layer with good solvent properties and excellent adhesiveness, and whose thickness can be easily adjusted, and a method for producing the same.

[Means for Solving the Problems] As a result of intensive studies on various materials for the above-mentioned problem to be solved, the inventors of the present invention have found the results described in JP-A-60-202128, JP-A-62-1705, etc. The present invention was completed based on the discovery that a partially crosslinked gel polymer, which is a methacrylic resin molding material, and a composition with improved fluidity thereof are extremely useful as a coating composition.

That is, the object of the present invention is to (A) crosslinkable monomers 1 to 6
0% by weight and (B) an unsaturated monomer consisting mainly of alkyl methacrylate and optionally containing a dissolved polymer thereof 99
A partially crosslinked gel-like polymer in which the polymer content of the mixture consisting of ~40% by weight is increased by 4 to 62% by weight over the polymer content in the mixture, provided that the total polymer content does not exceed 80% by weight. 100 parts by weight of the partially crosslinked gel polymer or its crushed partially crosslinked gel polymer and an alkyl methacrylate. This can be achieved by using a thermosetting coating composition with excellent adhesive properties, which is a composition consisting of 1 to 100 parts by weight of syrup containing a dissolved polymer.

Further, the object of the present invention is to obtain a crosslinking monomer (A) of 1 to 60% by weight and an unsaturated monomer (B) of 99 to 40% by weight, which is mainly composed of alkyl methacrylate and may contain the polymer dissolved therein. % by weight is partially polymerized in the presence of a polymerization initiator so that the total polymer content does not exceed 80% by weight, and the polymer content is 4% higher than the polymer content in the mixture. Adhesion in which 100 parts by weight of a partially crosslinked gel-like polymer increased by ~62% by weight and 1 to 100 parts by weight of syrup mainly composed of alkyl methacrylate and containing the dissolved polymer are crushed and mixed and kneaded substantially uniformly. This can also be achieved by a method for producing a thermosetting coating composition with excellent properties.

The present invention will be explained in more detail below.

The crosslinkable monomer (A) used in the present invention has at least two (meth)acryloyl groups in the molecule, and has 10 or less carbon atoms between the (meth)acryloyl groups. R, R3 is preferably a monomer having the following formulas (1) to (3)% (1) (where n is an integer of 3 to 6, and MA represents a methacryloyl group). (M)A-0-CH2-C-CH-0-(M)8
...(2) [Here, R, represents H, CH3, C2) 1s, CH2 R6 R2 represents H, CHs, CH20COC=CH2 (R, represents H, CH3) Cozon group R3 represents H and CH3 groups, R1, R2 and R:l are not hydrogen at the same time, and (M)A represents a methacryloyl group or an acryloyl group. ](M)A-0
+CH2CH20-h- (gate) A...
(3) [where n is 1 or 2, and (M)^ represents a methacryloyl group or an acryloyl group. ] is an unsaturated monomer represented by

Specifically, 1.3-propylene glycol dimethacrylate, 1.4-butylene glycol dimethacrylate, 1.6-hexanethiol dimethacrylate, 1,3
-Butylene glycol dimethacrylate, dimethylolethane dimethacrylate, 1,1-dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane tri(meth)
Acrylate, trimethylolpropane tri(meth)
Acrylate, tetramethylolmethane tri(meth)
Examples include acrylate, tetramethylolmethane dimethacrylate, ethylene glycol di(meth)acrylate, and diethylene glycol di(meth)acrylate. Among these crosslinkable monomers, those represented by the above formula (2) are preferably used. In terms of transparency and fluidity, 2,2-dimethylolpropane dimethacrylate (neopentyl glycol dimethacrylate) is particularly desirable.

The amount of these crosslinkable monomers (A) used is 1 to 60% by weight, preferably 2 to 50% by weight, more preferably 3 to 3% by weight.
It is 0% by weight. If the amount used is less than 1% by weight, the solvent resistance and heat resistance of the coating layer of the final coated product will not be sufficiently improved, and if it exceeds 60% by weight, the coating layer of the final coated product will not be sufficiently improved. This is undesirable because not only the layer becomes brittle, but also the fluidity of the coating composition tends to deteriorate.

In the present invention, the unsaturated monomer (B), which is mainly composed of alkyl methacrylate and may contain a polymer thereof, refers to alkyl methacrylate alone or other α, which is composed mainly of alkyl methacrylate and can be copolymerized with it, It is a syrup containing these polymers dissolved in a mixture with a β-ethylenically unsaturated S-mer, or in the monomer or monomer mixture. Alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, 5ec-butyl methacrylate, ter
t-butyl methacrylate, lauryl methacrylate,
These include cyclohexyl methacrylate, dicyclopentenyl methacrylate, etc. alone or as a mixture, but lower alkyl methacrylates in which the alkyl group has 1 to 4 carbon atoms are preferred, and methyl methacrylate is particularly preferred.

Examples of copolymer monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, lauryl acrylate, dicyclopentenyl acrylate, etc. Alkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3 −
Hydroxyalkyl methacrylates such as chloropropyl methacrylate, acrylic acid, methacrylic acid, acrylates such as odium acrylate and lead acrylate, methacrylates such as ozium methacrylate and lead methacrylate, vinyl chloride, vinyl acetate, acrylonitrile , methacrylnitrile, acrylamide, methacrylamide, styrene, α-methylstyrene, vinyltoluene, maleic anhydride, and the like.

In addition, the syrup containing the polymer of the alkyl methacrylate or the monomer mixture containing the alkyl methacrylate as a main component generally has a temperature of 1 to 30.0 at 25°C.
The monomer solution has a viscosity of 0 centivoise and contains 3 to 40% by weight, preferably 6 to 30% by weight of polymer.

The thermosetting coating composition according to the present invention is a mixture of the crosslinkable monomer (A) and an unsaturated monomer (B) which is mainly composed of alkyl methacrylate and which may contain the polymer dissolved therein. A gel-like part obtained by polymerizing by heating in the presence of a polymerization initiator, and stopping the reaction at the stage when only a part of the monomers present in the mixture has reacted without reacting the entire amount. It is made of crosslinked polymer.

In this case, the content of the polymers present in the partially crosslinked gel polymer is the crosslinkable monomer (A) and the unsaturated monomer (
4 to 62% by weight of the polymer content in the mixture of B);
Preferably 10-62% by weight, most preferably 15-6%
The total polymer content is increased by 2M% by weight, and the total polymer content does not exceed 80% by weight, preferably 62% by weight. If the above polymer content is less than 4% by weight, the product will take on a gel-like appearance and will be inconvenient to handle, while if it increases by more than 62% by weight or exceeds the upper limit of 80% by weight. is undesirable because it tends not to show good flow during molding.

When preparing a partially crosslinked gel polymer in the present invention,
A polymerization initiator is usually used, and one or a mixture of two or more selected from common low-temperature active polymerization initiators and high-temperature active polymerization initiators can be used. In general, low temperature active polymerization initiators are suitable for preparing partially crosslinked gel polymers.
Radical polymerization initiators of peroxides and azo compounds having a decomposition temperature of 50°C or less, preferably 26 to 45°C, particularly 26 to 41°C to obtain a 0 hour half-life are preferably used. The amount used is 0.001 to 1 based on the total amount of the crosslinkable monomer (A) and the unsaturated monomer (B).
% by weight, preferably from 0.0015 to 0.1% by weight.

In the present invention, the high temperature active polymerization initiator is particularly suitable for polymerization under coating treatment conditions, preferably a polymerization initiator with a decomposition temperature of 60 to 220°C, and a polymerization initiator with a decomposition temperature of 60 to 170°C for improved processing cycles and storage stability. A polymerization initiator having a decomposition temperature of C is more preferable.
) and the unsaturated monomer (B) 0.0
It is 1 to 5% by weight, preferably 0.02 to 4% by weight.

In the present invention, the partially crosslinked gel polymer is polymerized by heating a mixture of the crosslinkable monomer (A) and the unsaturated monomer (B) in the presence of a polymerization initiator. This polymerization reaction is carried out at a temperature of 10-80°C, preferably 35-65°C.
It is carried out for 0 to 200 minutes, preferably 20 to 150 minutes. Here, when both a low-temperature active polymerization initiator and a high-temperature active polymerization initiator are used together, almost all of the low-temperature active polymerization initiator is consumed, but most of the high-temperature active polymerization initiator remains unchanged at the reaction temperature. It remains and acts as a polymerization initiator under subsequent coating processing conditions.

These high-temperature active polymerization initiators may be added together with the low-temperature active polymerization initiators during the preparation of the partially crosslinked gel-like polymer, or when crushing and kneading with a kneader or extruder after preparing the partially crosslinked gel-like polymer. It may be added and mixed, and a high temperature active polymerization initiator is added to the syrup which is added for the purpose of modifying the fluidity and adhesion of the partially crosslinked gel polymer, and then crushed and mixed with the partially crosslinked gel polymer. It may be mixed uniformly.

A partially crosslinked gel-like polymer having a desired polymerization rate can be obtained by stopping the polymerization reaction by quenching or the like, but a mixture of the crosslinkable monomer (A) and the unsaturated monomer (B) It can be easily obtained by adding the following regulator during heating polymerization in the presence of the polymerization initiator. Such modifiers are 1.4(8)-P
-menthadene, 2,6-dimethyl-2.4.6-octatriene, 1.4-P-menthadene, ■,4-cyclohexadiene, and α-methylstyrene dimer.

Such a regulator is added to the total amount of the crosslinking monomer (A) and the unsaturated monomer (B) in an amount of o, oooi to 0.5.
% by weight, preferably 0.001-0.2% by weight, most preferably 0.005-0.1%.

In addition, in the raw material mixture before polymerization of the partially crosslinked gel polymer of the present invention, a chain transfer agent, a coloring agent, a filler,
Additives such as a mold release agent, an ultraviolet absorber, and a light stabilizer can be added.

The characteristics of the present invention are as follows: (A) 1 to 60% by weight of the crosslinkable monomer and (B) 99 to 99% of the unsaturated monomer, which is mainly composed of alkyl methacrylate and may contain a polymer thereof dissolved therein. A partially crosslinked gel-like polymer in which the polymer content of a mixture consisting of 40% by weight is increased by 4 to 62% by weight over the polymer content in the mixture, provided that the total polymer content does not exceed 80% by weight. is used as a thermosetting coating composition. The coating composition has a partially crosslinked gel-like polymer that is not sticky and has shape retention properties, so it can be used as a sheet,
It can be handled in any shape such as a rod, block, or pellet, and flows by applying shear stress at room temperature or elevated temperature.

Furthermore, it can be crushed for the purpose of improving fluidity.

By crushing particles with an average particle size of 5 mm or less, preferably 2n+m or less, extremely stable fluidity can be obtained and the total polymer content is relatively low, e.g.
If the content does not exceed 0% by weight, use a kneader such as a screw or calender roll, and if the polymer content is relatively high, use a pulverizer such as a ball mill or cutter mill. can be easily crushed.

Further, the thermosetting coating composition of the present invention contains a polymer mainly composed of alkyl methacrylate dissolved in 100 parts by weight of the partially crosslinked gel polymer or the crushed partially crosslinked gel polymer. syrup 1-100
By adding 10 to 50 parts by weight, it is possible to knead substantially uniformly, thereby providing the following favorable effects.

(1) Fluidity is further improved and processing can be performed at low pressure.

(11) Appropriate tackiness can be imparted.

(iii) When the total polymer content is relatively high, the adhesion of the coating layer can be improved.

(1) When coloring the coating layer, dyes and pigments can be mixed with syrup to uniformly color the coating layer, and running patterns and uneven spot patterns do not occur.

If the amount of syrup added exceeds 100 parts by weight, the shape retention of the composition will not be maintained, which is not preferable.

In addition, the syrup which is mainly composed of the alkyl methacrylate and may contain a dissolved polymer thereof means a syrup containing a polymer of the alkyl methacrylate or a monomer mixture whose main component is the alkyl methacrylate,
It preferably has a viscosity of 4 to 50 poise at 25°C, more preferably 6 to 20 poise, and may contain 50% by weight or less of a crosslinkable monomer if necessary, It is desirable to contain the crosslinkable monomer at the same concentration as the partially crosslinked gel polymer. As a method for adding this syrup and kneading it substantially uniformly, if the partially crosslinked gel polymer is not crushed, it can be carried out using the above-mentioned kneading machine or crusher, while if it is crushed, This can be carried out using a mixing agitator such as a super mixer or a Henshil mixer.

Here, "kneading substantially uniformly" means kneading the syrup kneaded into the coating composition by the above-mentioned kneading method to such an extent that it does not separate and flow out when left at room temperature for a short time. This state can be achieved by stirring and mixing using a stirrer for several minutes to about 15 minutes.

In addition, in the process of crushing the partially crosslinked gel polymer and/or in the process of adding and kneading syrup to the partially crosslinked gel polymer or its crushed polymer, release agents, colorants, fillers, It is also possible to incorporate additives such as ultraviolet absorbers and light stabilizers.

The thermosetting coating composition according to the present invention can be used for compression molding and
The composition is placed on a coating substrate by extrusion molding or the like, and heated at a temperature of 90 to 180°C, preferably 90 to 150°C, for 1 to 30 minutes, preferably 2 to 15 minutes, to form a desired coating layer. The coated product thus obtained has a crosslinked methacrylic resin coating layer and has a coating thickness of 0.1 to 511I.
A coating layer having a thick coating layer of I11, preferably 0.3 to 3+ nm, having good heat resistance and solvent resistance, and excellent adhesiveness having various thicknesses of the coating layer is formed.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Measurements and tests in the examples were conducted in the following manner.

Add 1,000 ppm of hydroquinone methyl ether to a Soxhlet extractor in room A and dissolve it in dichloromethane 1.
50mj! 15g of the above gel-like polymer was placed in strips in an extraction thimble, and reflux extraction was performed for 20 hours in a constant temperature water bath kept at 50°C. Put it in 1,200 ml of methanol, separate the polymer content, combine it with the polymer content in the filter paper, and heat at 55°.
Dry under reduced pressure at C until constant weight is reached, and determine the weight of the polymer.

Bending test method (ASTM 0790) for adhesion strength of covered products
In addition, the fractured surface of the coated product is visually observed to check for the occurrence of interfacial peeling at the interface of the coating layer.

A flannel soaked in toluene, ethanol, and isopropanol was placed on the surface of the coating layer side of each test piece of the coated product, and after each was left in a closed system for 8 hours, the surface that came in contact with the solvent was wiped to check for changes in the surface condition. Visually observe.

Shimadzu flow tester CFT-5
00 or 20), die: 1φ×If (m), temperature: 40°C, load 10kg/cffl or 4 kg/c
Measure under ill conditions.

Using a tack measuring machine (manufactured by Kuubishi Kagaku Kikai Seisakusho; Precision Strength Gauge PC-10), the measurement sample was sandwiched between Baralinks TS-20 (manufactured by Kuraray) and nylon, and a load of 10 kg was applied. Measurement is carried out under conditions adjusted so that the adhesive area is 40 x 40 (country) and the adhesive layer thickness is 0.3 mm.

Example 1 95 parts by weight of methyl methacrylate monomer, 5 parts by weight of neopentyl glycol dimethacrylate, 1.4(8)
-P-menthadene 0.01 part by weight, 2,2'azobis(4-methoxy-2,4-dimethylvaleronitrile)
0.01 part by weight, 0.3 parts by weight of 2-2-bis(1-butylperoxy)butane, and 0.2 M1 part of di-butyl peroxide were mixed and dissolved, and two glass plates and a gasket spaced at a distance of 10 After injection into a cell assembled into a tumor and polymerizing at 60°C for about 2 hours, a partially crosslinked gel-like polymer was obtained. The polymer content of this partially crosslinked gel polymer was 38.8%. When this polymer was extruded using an extruder with a screw diameter of 50 mm and an L/D=8, a thermosetting broken M-bottomed material with a maximum particle size of 2III11 or less was obtained. Next, 70 g of this composition was shaped into a dumpling and placed on a transparent acrylic resin substrate (-Kuraray; Rose Glass) with a thickness of 245 x 1'95 x 3.
It was placed in a mold cavity measuring 250 mm long, 200 mm wide and 30 mm deep, heated to 30"C, and the pressure was 30 kg/
After holding pressure at ci for 10 minutes, the mold was cooled to 100"C, opened and taken out. The coating composition flowed and covered the surface of the resin plate, and the coating thickness was approximately lllff1, with a pattern of material flow. A coated product with excellent appearance and transparency was obtained.The adhesive strength of the obtained coated product was measured using the bending test method (ASTM
D790), it showed a value of 1200 kg/d, indicating that it had sufficient adhesive strength and that no peeling at the coating interface was observed even if the material was broken. Also,
Even in a chemical resistance test in which the coated surface of the coated product was brought into contact with an organic solvent such as toluene or alcohol, there was no change in appearance and the product had excellent chemical resistance.

Examples 2 to 4 Coated products with good appearance were obtained in the same manner as in Example 1, except that the coated substrate was as shown in Table 1. Each molded product was tested for adhesive strength and chemical resistance in the same manner as in Example 1, and the results are shown in Table 1. All molded products had sufficient adhesive strength and good chemical resistance. However, no peeling was observed at the coating interface.

The following margin Examples 5 to 7 Using the same acrylic resin plate as in Example 1 as the coating base material, and using the same method as in Example 1, coated products with coating thickness shown in Table 2 and good appearance and transparency were obtained. Ta.

The adhesive strength and chemical resistance of each molded product were tested in the same manner as in Example 1, and the results are shown in Table 2. All coated products had sufficient adhesive strength and good chemical resistance. No peeling was observed at the coating interface.

Table 2 Examples 8 to 14 In the same manner as in Example 1, mixtures of monomers and catalysts shown in Table 3 with different composition ratios were injected and polymerized, and various polymer-containing mixtures were polymerized. After obtaining a partially crosslinked gel-like polymer of 10%, it was crushed to obtain a coating composition. For each composition, coated molded products with good appearance and transparency were obtained in the same manner as in Example 1, and then the adhesive strength and chemical resistance of these molded products were tested. It had good adhesive strength and chemical resistance, and no separation was observed at the coating interface.

Table 3 MMA Methyl methacrylate monomer NPGD
M neopentyl glycol dimethacrylate V-702,2'-azobis(4-methoxy-2,4-
Example 15.16 Changing the methyl methacrylate monomer to methyl methacrylate syrup containing polymethyl methacrylate,
Further, a coating composition was obtained in the same manner as in Example 1 except that only the composition shown in Table 4 was changed in the mixing ratio. Each composition was coated in the same manner as in Example 1 to obtain coated products with good appearance and transparency. When these coated products were tested for adhesive strength and chemical resistance, all coated products had sufficient adhesive strength and good chemical resistance.
No peeling was observed at the coating interface.

Below is the margin Table Book 1: Contains 25% by weight of polymethyl methacrylate with a viscosity average degree of polymerization of 1300. Syrup book 2: Contains 10% by weight of polymethyl methacrylate with a viscosity average degree of polymerization of 13,000 and has a viscosity of approximately 10 voids. Syrup Examples 17 to 19 with a viscosity of about 10 voids A composition containing a composition obtained by crushing the partially crosslinked gel polymer obtained in Example 1, and neopentyl glycol dimethacrylate in the same concentration as this composition contains, and 10M of polymethyl methacrylate with a viscosity average degree of polymerization of 10,000!
% containing methyl methacrylate syrup with a viscosity of about 10 voids in the ratio shown in Table 5 into a super mixer (■ manufactured by Kawata), and stirred and mixed for about 5 minutes to improve fluidity and stickiness as shown in Table 5. The process was carried out in the same manner as in Example 1 except that the above composition was used as a thermosetting coating composition, and a coated product with a coating layer thickness of about 1.211 inches and good appearance and transparency was obtained. When the coated products were tested for adhesive strength and chemical resistance, all coated products had sufficient adhesive strength and good chemical resistance, and no peeling was observed at the coating interface.

Table 5 Shimadzu flow tester FT 500, load 10 kg/afl Example 20.21 Portion containing 90% by weight of methyl methacrylate and 10% by weight of neopentyl glycol dimethacrylate as monomer composition, and a polymer content of 46% A composition obtained by crushing a crosslinked gel-like polymer, and a methyl methacrylate syrup having a viscosity of 8 poise and containing a crosslinking agent at the same concentration as this composition and containing polymethyl methacrylate having a viscosity and average degree of polymerization of 10,000. Same as Example 1 except that the composition was charged into a super mixer at the ratio shown in Table 6 and stirred and mixed for about 5 minutes to improve fluidity as shown in Table 6. The composition was used as a thermosetting coating composition. A coated product with a coating layer thickness of about 1 mm and good appearance and transparency was obtained.

Below are the blanks: Shimadzu Flow Tester CFT-20. Load 4kg/
ci Examples 22 to 25 The crushed partially crosslinked gel-like polymer obtained in Examples 8, 10 and 15.16, containing the same concentration of crosslinking agent as this polymer contains, and having a viscosity average degree of polymerization of 10 Methyl methacrylate syrup with a viscosity of about 10 poise containing 10% by weight of polymethyl methacrylate of . A composition with improved flowability was obtained.

Next, 63 g of this composition was placed on a long transparent acrylic resin substrate (manufactured by Mahiri Rare; Paraglass) measuring 696 embryos x 62 mm x 3 anus in the form of a string so as to have the same length as the substrate. It was placed in a belt-shaped mold of 700 mm wide, 65 rHrrl wide and 30 mm deep, which was heated to °C, and after holding at a pressure of 40 kg/c++I for 10 minutes, the mold was heated to 100 °C.
After cooling to °C, the mold was opened and taken out. The coating composition flowed in fine detail and covered the entire surface of the resin substrate, and a coated product with a coating thickness of approximately one cylinder and no pattern of material flow was obtained, with excellent appearance and transparency. The adhesive strength of this coated product and the chemical resistance of the coating material surface were good.

Below is a table with blank spaces Example 26 Methyl methacrylate 5 1 containing 10% by weight of polymethyl methacrylate with a viscosity average degree of polymerization of 10,000
90 parts by weight, 10 ethylene glycol dimethacrylate
parts by weight, 0.01 parts by weight of 1.4(8)-P-menthadene, 0.01 parts by weight of cumyl peroxyneodecanoate, and 0.3 parts by weight of di-t-butylperoxyl. A partially crosslinked gel-like polymer with a polymer content of 32% was obtained in the same manner as in Example 1 except that it was dissolved and injected into the cell.This polymer was crushed in the same manner as in Example 1,
When coated on an acrylic resin substrate, a coated product with good appearance was obtained.

The adhesive strength of this coated product and the chemical resistance of the coating material surface were good.

Example 27 1 ethylene glycol dimethacrylate of Example 26
．． A partially crosslinked gel polymer having a polymer content of 36% was obtained in the same manner as in Example 1 except that 6-hexanethiol dimethacrylate was used.

When this polymer was crushed in the same manner as in Example 1 and coated on an acrylic resin substrate, a coated product with a good appearance was obtained.

The adhesive strength of this coated product and the chemical resistance of the coating material surface were good.

Comparative Example 1 90 parts by weight of methyl methacrylate monomer, 10 parts by weight of 7-opentyl glycol dimethacrylate, 1.
A partially crosslinked gel polymer with a polymer content of 82% was obtained in the same manner as in Example 1, except that the amount of 4(8)-P-menthadene used was 0,001 parts by weight. This polymer was crushed into pieces with a maximum particle size of 2 mm or less using a cutter mill, and then coated on an acrylic resin substrate in the same manner as in Example 1. In the resulting coated article, the coating composition did not flow to the edges, and a flow pattern of the material was observed. Furthermore, when the adhesive strength of the coated product was measured using a bending test method, the coated product peeled off from the interface, and sufficient adhesiveness was not obtained.

Comparative Example 2 A polymer with a polymer content of 2.8% was obtained in the same manner as in Example 1, except that the amount of L4(8)-P-menthadene used was 0.55 parts by weight. Although this polymer does not exhibit sufficient shape retention, when it was placed on an acrylic resin substrate and coated in the same manner as in Example 1, most of the coating composition flowed out of the mold.

A part of the surface of the coated product taken out from the mold was coated very thinly, but the coating layer was also in an uncured state.

Comparative Examples 3-5 Examples 10, 15. 696m+nX 62mmX 3mm thick transparent acrylic in the same manner as Example 23゜24.25 except that the crushed coating composition obtained in '16 was used without mixing with syrup to improve the adhesion and fluidity. An attempt was made to coat a long resin substrate (manufactured by Kuraray Co., Ltd.; Bara Glass). First, an attempt was made to form the coating composition into a string of the same length as the resin substrate, but due to insufficient adhesiveness, it fell apart and could not be formed into a string.

Next, an attempt was made to place the loose coating composition on a resin substrate and pour it into the mold, but since the substrate was narrow and long, some of the composition spilled out and the prescribed amount could not be poured. . For this reason, the obtained coated product was not coated in detail, and a product with good appearance could not be obtained.

[Effect of the invention] As described above, the present invention provides (A) crosslinkable monomers 1 to 6
0% by weight and (B) an unsaturated monomer consisting mainly of alkyl methacrylate and optionally containing a dissolved polymer thereof 99
A partially crosslinked gel-like polymer in which the polymer content of a mixture consisting of ~40% by weight is increased by 4 to 62% by weight over the polymer content in the mixture, provided that the total polymer content does not exceed 80% by weight. 100 parts by weight of the partially crosslinked gel-like polymer or its crushed partially cross-linked gel-like polymer, and syrup 1 to 1, which is mainly composed of alkyl methacrylate and contains the polymer dissolved therein. 10
Since it is a thermosetting coating composition consisting of 0 parts by weight, it has permeability and fluidity comparable to that of syrup, so this composition can be used to provide good heat resistance, solvent resistance, and adhesive properties. It is effective in forming an excellent coating layer, and since the composition has good fluidity and is easy to handle, the thickness of the coating layer can be adjusted freely, and it is especially suitable for forming thick coating layers. Suitable for processing.

In addition, in the present invention, a mixture containing 1 to 60% by weight of the crosslinkable monomer (A) and 99 to 409 to 40% by weight of the unsaturated monomer (B) is partially polymerized in the presence of a polymerization initiator. 100 parts by weight of a partially crosslinked gel-like polymer with a polymer content increased by 4 to 62% by weight over the polymer content in the mixture, and an alkyl methacrylate within a range not exceeding 80% by weight. This is a method for producing a thermosetting coating composition with excellent adhesive properties, in which 1 to 100 parts by weight of syrup, which is mainly composed of 1 to 100 parts by weight of syrup containing a melted polymer thereof, is mixed substantially uniformly. It is useful because it can easily provide a coating composition that has permeability and fluidity and is easy to handle.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Scope of Claims] 1 (A) 1 to 60% by weight of a crosslinkable monomer and (B) 99 to 40% by weight of an unsaturated monomer mainly composed of alkyl methacrylate and optionally containing a dissolved polymer thereof.
The total polymer content of the mixture is 80%.
A thermosetting coating composition with excellent adhesion, characterized by comprising a partially crosslinked gel-like polymer whose polymer content is increased by 4 to 62% by weight over the polymer content in the mixture, within a range not exceeding 4% by weight. . 2. The coating composition according to claim 1, wherein the partially crosslinked gel polymer is crushed to an average particle size of 5 mm or less. 3 Partially crosslinked gel polymer 100 according to claim 1 or 2
1. A coating composition comprising 1 to 100 parts by weight of syrup mainly composed of alkyl methacrylate and containing a dissolved polymer thereof. 4. The crosslinkable monomer (A) has at least two (meth)acryloyl groups in the molecule, and the number of carbon atoms present between the (meth)acryloyl groups is 10 or less. A coating composition according to any one of claims 1 to 3. 5. The coating composition according to claim 1, wherein the alkyl methacrylate is a lower alkyl methacrylate. 6. The coating composition according to claim 5, wherein the alkyl methacrylate is methyl methacrylate. 7. Initiate polymerization of a mixture consisting of 1 to 60% by weight of a crosslinkable monomer (A) and 99 to 40% by weight of an unsaturated monomer (B) which is mainly composed of alkyl methacrylate and may contain a melted polymer thereof. A portion partially polymerized in the presence of an agent to increase the polymer content by 4 to 62% by weight over the polymer content in the mixture, provided that the total polymer content does not exceed 80% by weight. Excellent adhesiveness characterized by crushing and mixing 100 parts by weight of a crosslinked gel polymer and 1 to 100 parts by weight of a syrup mainly composed of alkyl methacrylate and melting the polymer and kneading them substantially uniformly. A method for producing a thermosetting coating composition.