JPS61225207A - Syrup composition for crosslinked methacrylic resin - Google Patents

Abstract

PURPOSE:The titled composition which can give a crosslinked methacrylic resin excellent in transparency, prepared by mixing a monoethylenically unsaturated monomer with its polymer and a specified polyfunctional monomer. CONSTITUTION:A 1-4C alkyl group-containing alkyl methacrylate (e.g., methyl methacrylate)-based monoethylenically unsaturated monomer (A) is mixed with a polymer (B) of component A, having an average MW of 1X10<4>-8X10<6> and at least one polyfunctional monomer (e.g., 1,6-hexanediol methacrylate) (C), as a crosslinking agent, of formula I (wherein X is formula II-IV, m is 6-30, Y is OH or a 3-12C hydrocarbon residue which may be substituted with a halogen, R is H or CH3 and n is 1-15), e.g., 1,6-hexanediol methacrylate, at a mixing ratio lying within the inside of the closed region in the diagram (wherein x is C/(A+B+C)wt% and y is B/(A+B)wt%], and the obtained mixture is polymerized at 10-150 deg.C, preferably 25-130 deg.C in the presence of 0.0001-2wt% polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a silica composition for crosslinked methacrylic resin. More specifically, the present invention relates to a silica composition suitable for producing a crosslinked methacrylic resin having excellent transparency.

(Prior art) In general, methacrylic resins whose main component is methyl methacrylate are used in various fields such as lighting covers, automobile parts, signboards, decorations, and miscellaneous goods due to their excellent weather resistance and outstanding transparency. However, since the methacrylic resin is a linear polymer, it has disadvantages in that it has insufficient heat resistance, solvent resistance, impact resistance, and surface hardness.

For example, the limit of heat resistance is about IOO'C, and the current situation is that it cannot sufficiently meet the demands of various fields that require heat resistance. For example, it cannot be used as a cover for a headlamp as an automobile part, and in the case of a tail lamp, the lamp itself is larger than conventional products, and the amount of heat generated due to increased illuminance increases, and the wall thickness is thinner due to cost reduction. Improved heat resistance is required from both sides, and applications are expected to expand to parts whose temperature rises significantly under direct sunlight, such as meter covers for automobiles and two-wheeled vehicles (motorcycles), and covers for water heaters that use solar thermal energy. Therefore, it is hoped that a methacrylic resin that can withstand temperatures above the boiling point of water will be developed.

Conventionally, in order to improve the heat resistance of methacrylic resins, methods have been developed in which methyl methacrylate and α-methylstyrene are copolymerized (U.S. Pat. No. 3,135°723), and methyl methacrylate, α-methylstyrene, and maleic anhydride are copolymerized. Polymerization method (Japanese Patent Publication No. 45-31,953,
A number of methods have been proposed, including a method of copolymerizing methyl methacrylate, α-methylstyrene and maleimide (Japanese Patent Publication No. 48-95,490).

However, although these methods improve heat resistance, the polymerization rate is extremely slow, the polymerization rate does not increase and a high polymerization rate cannot be obtained, and the polymerization rate cannot be obtained efficiently in a relatively short time. Even if it is obtained, it has both advantages and disadvantages, such as a strong polymer color band and reduced transparency, weather resistance, surface hardness, mechanical strength, etc., making industrial production extremely difficult, and currently it has not been put into practical use. .

On the other hand, if a crosslinked structure is generally introduced into a linear polymer, it is easy to think that the above-mentioned drawbacks in heat resistance, solvent resistance, etc. can be improved, and the aim is to be achieved by creating a crosslinked polymer. It is well known that many attempts have been made.

Generally, methacrylic resins are produced by polymerizing raw material monomers or their partial polymers (hereinafter referred to as shirubu, including those in which polymers are dissolved in monomers) in a mold or the like. Monomers have many inconveniences and inconveniences in handling, such as the fact that monomers tend to leak from the mold due to their low viscosity, and even if deaeration is performed prior to polymerization, oxygen tends to dissolve again when exposed to air. Usually, high viscosity Shirabu is used as a raw material. Because it already contains a portion of the polymer, Shirabu is advantageous in that it takes less time to polymerize than monomers. In this case, a crosslinking agent for introducing crosslinking bonds will be added to this sill. This is because if a crosslinking agent is mixed with a monomer and the mixture is partially polymerized, a crosslinked polymer is generated and tends to lose fluidity, making subsequent handling difficult.

On the other hand, different types of polymers are generally not compatible, except for special exceptions, and when they coexist in a mixed state, macroscopic or microscopic phase separation occurs. Therefore, when two or more polymers with different refractive indexes are mixed, even though they are transparent individually, light is reflected at the interface between the separated phases.
It is well known that this can result in dispersion and, as a result, loss of transparency.

(Problems to be Solved by the Invention) Therefore, (a) a monoethylenically unsaturated monomer whose main component is an alkyl methacrylate having 1 to 4 carbon atoms in an alkyl group, and (b) a carbon atom in an alkyl group. When carrying out polymerization by adding (C) a polyfunctional monomer as a crosslinking agent to a sillage consisting of a polymer of a monoethylenically unsaturated monomer mainly composed of alkyl methacrylate of numbers 1 to 4, (b) 1 coalescence that existed in , and the newly generated (a
> The above relationship also applies between the monomer and (C) a polymer made of the monomer, and a transparent crosslinked resin cannot necessarily be obtained.

Therefore, an object of the present invention is to provide a novel silica composition for crosslinked methacrylic resin. Another object of the present invention is to provide a silica composition suitable for producing a crosslinked methacrylic resin having excellent transparency.

(Means for solving the problem) These various terms include (a) the number of carbon atoms in the alkyl group is 1;
-4 monoethylenically unsaturated monomer mainly composed of alkyl methacrylate, (b) alkyl group having 1 carbon atom
~4 alkyl methacrylate as a main component, and (C) the following general formula 1 [wherein, is an integer from 6 to 30. >, -'r'-o-(
However, Y is a hydrocarbon residue having r&3 to 12 carbon atoms which may be substituted with a hydroxyl group or a halogen atom.

) or CH3 (however, R is a hydrogen atom or a methyl group, and 1
is an integer from 1 to 15. ). ) consisting of at least one polyfunctional monomer represented by (a) the monoethylenically unsaturated monomer, (b) the polymer and (C
) of the total weight of the polyfunctional monomer (% by weight); (a) the monoethylenically unsaturated monomer; and (b) the polymer. of the total (
b) The ratio y (wt%) of the polymer is on the x-y coordinates at points (2, 2>, (2, 30), (45, 30)
, (13,16>, (13,10), (24,4>, <
50.4>, (50,2> and (2,2>) in this order. This is achieved by a crosslinked methacrylic resin sill composition with excellent transparency, which is located inside a closed region formed by connecting in this order. Ru.

In the present invention (a > number of carbon atoms of alkyl group 1 to 4
Examples of monoethylenically unsaturated monomers containing an alkyl methacrylate as a main component include the alkyl methacrylate alone or a mixture of the alkyl methacrylate and an α,β-ethylenically unsaturated monomer that can be copolymerized with the alkyl methacrylate. . In the case of such a monomer mixture, the alkyl methacrylate content is desirably 50 mol% or more, and preferably 60 mol% or more. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, 0-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, and tert-butyl methacrylate, with methyl methacrylate being particularly preferred.

As the copolymerizable monomer, other than the alkyl methacrylate (for example, methyl methacrylate) used as the main component, other fulkyl methacrylates (for example, the above-mentioned alkyl methacrylate, 2-ethylhexyl methacrylate,
lauryl methacrylate, cyclohexyl methacrylate, etc.), methyl acrylate, ethyl acrylate, n
-propyl acrylate, isopropyl acrylate,
Alkyl acrylates such as n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
Hydroxyalkyl acrylates such as 3-hydroxypropyl acrylate, 4-hydroxypropyl acrylate, 2-hydroxy-3-chloropropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate , hydroxyalkyl methacrylates such as 2-hydroxy-3-chloropropyl methacrylate, acrylic acid,
Acrylic acid salts such as methacrylic acid, neodymium acrylate, lead acrylate, boron acrylate, methacrylates such as neodymium methacrylate, lead methacrylate, boron methacrylate, vinyl chloride, vinyl acetate, acrylonitrile,
Methacrylate tolyl, acrylamide, methacrylamide, styrene, α-methylstyrene, vinyltoluene,
Examples include maleic anhydride.

The polymer of (b) monoethylenically unsaturated monomer used in the present invention has an average molecular weight of about 1X104 to 8X106.
, preferably about 5X104 to 5X106.

The polyfunctional monomer (C) used as a crosslinking agent in the present invention is a compound represented by the general formula (2). This compound can be broadly classified into the following general formula II.

Either III or IV.

(However, in the formula, ■ is an integer of 6 to 30.) (However, in the formula, Y is substituted or unsubstituted with a hydroxyl group or a halogen atom, preferably 3 to 12 carbon atoms substituted with a hydroxyl group or unsubstituted. , preferably 3 to 8 hydrocarbon residues) and (wherein R is a hydrogen atom or a methyl group, preferably a hydrogen atom, and n is an integer of 1 to 15, preferably 1 to 10) ).

Specific examples of these polyfunctional monomers include polyethylene glycol dimethacrylate having 6 to 30 repeating units of polyoxyethylene, 1,3-propanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanethiol dimethacrylate, dimethylolethane dimethacrylate, 1,1-dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane dimethacrylate, trimethylolpropane dimethacrylate, tetramethylolmethane dimethacrylate,
2,2-bis[4-(methacryloyloxylopane, 2,
Examples include 2-bis[4-(methacryloyloxydipropoxy)phenyl]propane and 2,2-bis[4-(methacryloyloxytripropoxy)phenyl]propane.

In the present invention, (a) the monoethylenically unsaturated monomer, (b) the polymer of the unsaturated monomer, and (C) the polyfunctional monomer that accounts for Ratio of functional monomer × (% by weight) and (%) in the total of <a> the monoethylenically unsaturated monomer and (b) the polymer.
b) The ratio y (wt%) of the polymer is on the x-y coordinates at points (2,2), (2,30>, (45,30>)
, (13,16), (13,10>, (24,4>, (
50,4>, (50,2> and (2,2) in this order), and when it is within this closed region, the methacrylate obtained by polymerizing the silica composition The resin molding has extremely good transparency and also shows improved physical properties based on the crosslinked structure.

If X is less than 2, the effect of introducing crosslinking will not be sufficient, and if X exceeds 50, the crosslinking density will become excessive, leading to a deterioration of some physical properties.

In the range where (1) is less than 2, the viscosity of the Shirabu composition is insufficient and the above-mentioned advantages expected when using Shirabu are not exhibited, and in the region where (1) is more than 30, the polymer content is high, so the viscosity of the Shirabu composition is insufficient. This makes handling difficult.

The thus obtained silica composition is polymerized in the presence of a polymerization initiator. This polymerization reaction is 10' to 150
℃, preferably at a temperature of 25° to 130°C.

The polymerization initiator is usually added in an amount of 0.0 to the silica composition.
0.001 to 2% by weight, preferably 0.001 to 0.5% by weight. Typical polymerization initiators include lauroyl peroxide, to-butyl baroxy isabropyl carbonate, benzoyl peroxide, dicumyl peroxide, t-butyl peroxy acetate, and t-butyl peroxy isabropyl carbonate.
-butyl peroxybenzoate, di-t-butyl peroxide, azobisisobutyronitrile and the like.

(Example) Next, the present invention will be described in further detail by giving examples. In the following examples, "parts" are parts by weight unless otherwise specified.

In addition, the total light transmittance and haze are based on JISK7105.
Measured at room temperature according to Regarding impact resistance, Izot impact strength was measured according to JIS K7110 using a No. 2 test piece without making a notch. Heat distortion temperature is JIS
It was measured in accordance with K7207 (bending stress 18.6 parts Mcm2).

Examples 1 to 6 and Comparative Example 1 A methyl methacrylate solution of polymethyl methacrylate obtained by prepolymerizing methyl methacrylate was added with the first
The polyfunctional monomers shown in the table were dissolved and mixed to obtain the syrup compositions shown in the table. 0 per 100 parts of this Shirabu composition
．． 1 part of t-butyl peroxyisobutyrate was added and dissolved, and a soft vinyl chloride resin was used as a gasket.
Pour into a cast polymerization cell made of a sheet of tempered glass, and
3.5 hours at °C, 2 hours at 70'C, 2 hours at 120'C
After polymerizing for a period of time, the polymerized products were taken out and each had a thickness of 5 m.
A transparent plate-like polymer of m was obtained. The total light transmittance, haze, impact resistance, and heat distortion temperature of these plate-like polymers were measured, and the results shown in Table 1 were obtained.

Week f11a Example 1 7.0X10' 1.6-hexanethiol dimethacrylate 15 20 Example 2 2
．． 2X10' 2.2 -Dimethylolpropane dimethacrylate 15 6 Example 3 2.2X10
@ Polyethylene glycol dimethacrylate
10 25 (number of ethylene oxide repeating units 1
4) 1 example 4 2.2X10$ 2.2-bis[4-
(Metaku! Joi o-8-shiji 10 1
0ethoxy)phinyl]propane Example 5 1.8X10' 2.2-dimethylolpropane dimethacrylate 20251 Example G 2.3
X108 1,3-butanediol dimethacrylate 5 10 intersection 1 2.2X10'
1.6-hexanethiol dimethacrylate
20 10 Izot 89.6 2.6 19 131
91.4 1.9 22 122
90.7 1.5 26 94
90.5 1.4 27 107
91.5 0.8 21 128
90.5 2.1 23 116
88.017.2 - Example 7 Monomer mixture consisting of methyl methacrylate and styrene (styrene/methyl methacrylate lfi ratio 2/9
8) In (a), the average molecule! 1.2×105 methyl methacrylate-methyl acrylate covalent combination (methyl acrylate/methyl methacrylate weight ratio 6/94'
) to the solution obtained by dissolving y = 20, 1,3-butanediol dimethacrylate was added to x = 10
The mixture was mixed and dissolved in the following proportions. This Shirabu composition 100
Add and dissolve 0.1 part of t-butylperoxyisobutyrate per part, polymerize in the same manner as in Example 1, and form a 5 m thick
A transparent plate-like polymer of m was obtained. The total light transmittance of this product was 91.1% and the haze was 1.5%. Further, the Izot impact strength was 30.5k (]φCm/Cm.

Example 8 3% by weight of polymethyl methacrylate with an average molecular weight of 7.0×105 obtained by prepolymerizing methyl methacrylate
to 70 parts of methyl methacrylate solution containing 2.2
- 30 parts of dimethylolpropane dimethacrylate, 1.
4(8)-1)-mentagene 0.01 part, 2,2'-
Azobis(4-methoxy-2,4-dimethylvaleronitrile>0.003 part and 0.3 part of di-t-butyl peroxide were dissolved and mixed, and the mixture was poured into a cast polymerization cell similar to Example 1, Polymerization was carried out at 50° C. for 3 hours and taken out to obtain a gel-like polymer. This gel-like polymer was press-molded using a mold capable of obtaining a flat plate of 15 cm square and 5 mm thick. Mold temperature: 130 °C, press maximum pressure 65kg/C111
2 for 15 minutes, the mold was cooled to 120° C. and taken out to obtain a transparent plate-like polymer. The total light transmittance of this plate-like polymer was 91.8%, and the haze was 1.1%.

In addition, the Izotsu impact strength is 15.0 ka-c towns/cm.
Met.

[Brief explanation of drawings]

The drawing is an x-y coordinate diagram showing the relationship between the ratio x (wt%) of the polyfunctional monomer and the ratio y (wt%) of the polymer in the silica composition according to the present invention.

Claims (5)

[Claims] (1) (a) A monoethylenically unsaturated monomer whose main component is an alkyl methacrylate whose alkyl group has 1 to 4 carbon atoms, (b) whose main component is an alkyl methacrylate whose alkyl group has 1 to 4 carbon atoms. and (c) the following general formula I ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, in the formula, X is -(CH_2CH_2O)-_m(
However, m is an integer from 6 to 30. ), -Y-O-(
However, Y is a hydrocarbon residue having 3 to 12 carbon atoms which may be substituted with a hydroxyl group or a halogen atom. ) or ▲Mathematical formulas, chemical formulas, tables, etc.▼ (However, R is a hydrogen atom or a methyl group, and n
is an integer from 1 to 15. ). ] (a) the monoethylenically unsaturated monomer; (b)
The ratio x (wt%) of the polyfunctional monomer (c) to the total of the polymer and (c) the polyfunctional monomer, and (a)
The ratio y (wt%) of the polymer (b) to the total of the monoethylenically unsaturated monomer and the polymer (b) is
On the x-y coordinates, the points (2, 2), (2, 30),
(45, 30), (13, 16) (13, 10), (2
4,4), (50,4), (50,2) and (2,2
) in this order, forming a syrup composition for a crosslinked methacrylic resin having excellent transparency. (2) The polyfunctional monomer has the general formula II ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (II) [However, in the formula, m is an integer from 6 to 30. ] The syrup composition according to claim 1, which is at least one compound represented by the following. (3) The polyfunctional monomer has the general formula III ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) [However, in the formula, Y is a hydroxyl group or a halogen atom substituted or unsubstituted carbon atom with 3 to 12 carbon atoms. It is a hydrocarbon residue. ] The syrup composition according to claim 1, which is at least one compound represented by the following. (4) The polyfunctional monomer has the general formula IV ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (IV) (However, in the formula, R is a hydrogen atom or a methyl group, and n is an integer from 1 to 15. ) at least 1
The syrup composition according to claim 1, which is a compound of seeds. (5) (a) the monoethylenically unsaturated monomer and (b)
) The syrup composition according to any one of claims 1 to 4, wherein the polymer contains methyl methacrylate as a main component.