JP2707458B2 - Acrylic syrup composition - Google Patents

Description

The present invention relates to a molding acrylic syrup composition having excellent transparency, low shrinkage, boiling resistance and the like.

[Problems to be solved by conventional technology and invention]

BACKGROUND ART An acrylic syrup composition containing methyl methacrylate as a main component is used for a glass fiber reinforced plate, a kitchen countertop, a wash basin, and the like because of its excellent transparency and weather resistance. Further, recently, there is a growing expectation as a building material replacing polyester, and improvements in boiling resistance, heat resistance, impact resistance and the like are desired.

Generally, as a method for improving the heat resistance of a methacrylic resin, a method of copolymerizing α-methylstyrene (US Pat.
P. 3,135,723), a method of copolymerizing maleic anhydride (JP-B-45-31953, JP-B-49-10156), a method of copolymerizing methyl methacrylate, α-methylstyrene and maleimide (JP-A-48-95490). ) And many other methods.

However, although the heat resistance of each of these methods is improved, the polymerization rate is extremely slow, the transparency of the polymer,
There are drawbacks such as a decrease in weather resistance and boiling resistance.

Furthermore, when these polymerization methods are used for acrylic syrup, a molded product cannot be obtained efficiently due to the slow reaction during molding due to the influence of cross-linkable unsaturated monomers remaining in the acrylic syrup, and practical use is not possible. There are many problems to do.

Among the physical properties of acrylic syrup, especially as a method for improving boiling resistance and heat resistance, it is effective means to copolymerize a crosslinkable unsaturated monomer such as glycol diacrylate or dimethacrylate, In order to make the acrylic syrup moldable, the viscosity must be kept within a certain range.

As a result, the resin content in the acrylic syrup is reduced, and the molded product cracks or sinks (a partially corrugated concave portion during molding) during post-polymerization and molding.
In addition, there is a drawback that if an attempt is made to increase the resin content while keeping the viscosity at a level capable of being molded, the molecular weight is reduced, and boiling resistance, heat resistance, strength and impact resistance are extremely reduced. .

Therefore, an object of the present invention is to provide an acrylic syrup composition having a reduced shrinkage, improved moldability, and excellent transparency while maintaining transparency.

[Means and actions for solving the problem]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a highly crosslinked acrylic syrup composed of an ethylenically unsaturated monomer containing methyl methacrylate as a main component and a crosslinkable unsaturated monomer. It has been found that the object of the present invention can be achieved by blending a resin having a double bond in a radically polymerizable resin, thereby completing the present invention.

That is, the present invention relates to the following 80 to 20% by weight of component A and component B
The present invention relates to an acrylic syrup composition comprising 20 to 80% by weight.

(A) Component A: Acrylic obtained by adding 0.002 to 0.03 mol of a crosslinkable unsaturated monomer to the total number of moles of ethylenically unsaturated monomer having methyl methacrylate as a main component, and copolymerizing the same. Syrup has a weight average molecular weight (MW) of 2000
00 to 800,000, number average molecular weight (MN) is 2000 to 100,000,
Highly crosslinked acrylic syrup whose ratio (MW / MN) is 2 to 40.

(B) Component B: an acrylic syrup containing an ethylenically unsaturated monomer and having 50 to 90% by weight of a vinyl ester resin or an acrylic resin having at least two or more ethylenically unsaturated groups in the resin.

The present invention is an acrylic syrup obtained by copolymerizing an ethylenically unsaturated monomer containing methyl methacrylate as a main component and a crosslinkable unsaturated monomer. Low shrinkage with transparency maintained by adding ester resin or acrylic resin
It is an acrylic syrup composition for molding excellent in boiling resistance and the like.

 Hereinafter, the present invention will be described in detail.

First, a crosslinkable unsaturated monomer is added in an amount of 0.002 to 0.03 mol, preferably 0.01 to 0.02 mol, based on the total number of moles of the ethylenically unsaturated monomer having methyl methacrylate as a main component of 1, and copolymerized. A highly crosslinked acrylic syrup (A) of 10 to 50% by weight is obtained.

The method for producing the highly crosslinked acrylic syrup (A) is not particularly limited, but an azobis-based or organic peroxide-based polymerization initiator is added to a mixture of the above monomers, and if necessary, n
-Add a molecular weight modifier such as dodecyl mercaptan, thioglycolic acid, heat polymerization between 60 and 120 ° C, add a polymerization inhibitor when the viscosity of the polymerization solution is 2 to 6 poise, and cool.
The desired highly crosslinked acrylic syrup (A) is obtained.

This highly crosslinked acrylic syrup (A) has a weight average molecular weight (MW) of 200,000 to 800,000 and a number average molecular weight (MN) of 2,000.
0 to 100,000, the ratio (MW / MN) is 2 to 40, preferably 5 to
A value of 30 is desirable.

The amount of methyl methacrylate used as the main component is 0.5 to 1 in the total number of moles 1 of the ethylenically unsaturated monomer.
1.0 mole, preferably 0.7 to 1.0 mole. In consideration of the hardness, heat resistance and weather resistance of the final molded product, it is not preferable that the content of methyl methacrylate is less than 0.5 mol.

Examples of ethylenically unsaturated monomers other than methyl methacrylate used as the main component include, for example, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate,
Methacrylic acid and its esters such as 2-ethylhexyl methacrylate, lauryl methacrylate, propyl methacrylate, isopropyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, methacrylic acid, Acrylic acid and its esters such as methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, isopropyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, acrylic acid, etc., Examples include vinyl acetate, acrylonitrile, acrylamide, methacrylamide, styrene, α-methylstyrene, and maleic anhydride.

Examples of the crosslinking unsaturated monomer include, for example, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,
3-butylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate , Trimethylolpropane trimethacrylate, trimethylolethane triacrylate, trimethylolethane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethanetrimethacrylate, tetramethylolmethanetetraacrylate, and the like.In order to obtain this crosslinkable acrylic syrup In particular, polyethylene glycol dimethacrylate is desirable.

The amount of the crosslinkable unsaturated monomer to be added is 0.002 to 0.03 mol per 1 mol of the total number of ethylenically unsaturated monomers.
However, crosslinkable unsaturated monomers have a wide range of molecular weights and many have different numbers of double bonds in one molecule.Therefore, the amount of these added is the amount of double bonds contained in one molecule. It is desirable to define by the number (n).

When represented by the general formula, the amount of the crosslinkable unsaturated monomer having two or more double bonds in one molecule is 0.01 / n to 0.06 / n mol.

The crosslinkable unsaturated monomer used in the present invention has 2 to 4 double bonds in one molecule, that is, n = 2 to 4
Is the case.

When n = 2, the amount used is 0.005 to 0.03 mol, n
= 3, the amount used is 0.0034-0.02 mol, n = 4
In this case, the amount used is 0.0025 to 0.015 mol.

When the amount of the crosslinkable unsaturated monomer is less than 0.002 mol, the crosslink density of the acrylic syrup is too small, and the highly crosslinked acrylic syrup intended for the present invention cannot be obtained. On the other hand, if it exceeds 0.03 mol, it is difficult to control the temperature at the time of copolymerization, runaway easily, and even if copolymerized, the degree of polymerization is too small, which is not preferable as a molding material.

Next, regarding the vinyl ester resin and the acrylic resin to be added, examples of the vinyl ester resin include a bisphenol-based epoxy acrylate resin, a novolak-based epoxy acrylate resin, and an isophthalic acid-based vinyl-modified unsaturated polyester resin.

These vinyl ester resins are used as an acrylic syrup containing 50 to 90% by weight and having a viscosity of 3 to 100 poise.

On the other hand, for acrylic resin, for example,
By a method as shown in 19601, a glycidyl group-containing monomer is copolymerized in an acrylic resin to obtain a copolymer having two or more glycidyl groups, which has reactivity with a glycidyl group. Two or more ethylenes containing 50 to 90% by weight of an ethylenically unsaturated monomer containing a monomer and reacting 1 to 100% of glycidyl groups in the resin with the ethylenically unsaturated monomer; An ethylenically unsaturated monomer having a reactivity with a glycidyl group is copolymerized in an acrylic syrup or an acrylic resin having a viscosity of 3 to 100 poise containing a resin having a glycidyl group. It is used as an acrylic syrup having a viscosity of 3 to 100 poise containing a resin having two or more ethylenically unsaturated groups obtained by reacting 1 to 100% of an ethylenically unsaturated monomer. As such an acrylic syrup of the component B,
There are commercially available acrylic resins SM-100B-4 and SM-100B-3 (both manufactured by Mitsui Toatsu Chemicals, Inc., trade names).

These acrylic syrups are mixed with the above-mentioned highly crosslinked acrylic syrup (component A), and the total amount is 100% by weight.
And

The amount of the crosslinkable unsaturated monomer contained in the mixed acrylic syrup is 1 to 30% by weight, preferably 3 to 20% by weight in the mixed solution in which the component A and the component B are mixed.
% By weight. If it is less than 1% by weight, the boiling resistance becomes insufficient, and if it exceeds 30% by weight, the originally intended effect of low shrinkage may be impaired, which is not preferred.

The mixing amount of the component A and the component B depends on the resin content contained in each of the highly crosslinked acrylic syrup and the acrylic syrup to be used, but it is desirable that the component A / B component = 20/80 to 80/20.

In general, when a different resin is mixed as a low-shrinkage agent, transparency tends to decrease, and the mixture tends to be cloudy.
Use of the components does not impair transparency.

The component A obtained by the present invention tends to be difficult to stir and mix alone, but when the component B is mixed, stirring and mixing can be easily performed. In particular, when an inorganic filler is used, it is difficult to increase the viscosity as compared with ordinary acrylic syrup, and the filler can be filled at a high level. The acrylic syrup composition obtained in the present invention is blended with additives such as inorganic fillers, other fillers, pigments, coloring agents such as dyes, polymerization initiators, polymerization accelerators, if necessary, a mold, It is poured into a mold such as a resin mold or a glass mold and cured under heating or room temperature under pressure or normal pressure to obtain a marble-like molded product.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Examples 1 to 4 In a flask having a thermometer and a stirrer, 1000 g of methyl methacrylate and 55 g of polyethylene glycol # 400 dimethacrylate (NK ester 9G, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name)
Was charged, and a molecular weight modifier n-dodecyl mercaptan 5.0 g
After heating to 80 ° C, 0.01 g of azobisisobutyronitrile, a polymerization initiator, was added, and the mixture was reacted at 90 ° C for 5 hours, and had a viscosity of 4.5 poise (MN: 42000, MW: 450,000, MW / MN). :Ten.
7) A component (I) was obtained.

Next, B component was added to the obtained A component (I) as shown in Table 1 to obtain respective acrylic syrup compositions. In addition, SM100B-3 manufactured by Mitsui Toatsu Chemicals Co., Ltd., a vinyl ester resin as the B component, is obtained by adding 690 g of a bisphenol-based epoxy resin to 200 g of methacrylic acid and 0.5 g of triethylamine.
Is added to the vinyl ester resin obtained by the addition reaction, and 600 g of a styrene monomer is added to the vinyl ester resin having 60% by weight of a vinyl ester resin having two or more ethylenically unsaturated groups.
Acrylic syrup. In addition, Mitsui Toatsu Chemical Co., Ltd.
Company SM100B-4, styrene, methyl methacrylate, glycidyl methacrylate 300 g of acrylic powder obtained by copolymerization, 100 g of methyl methacrylate, styrene
An acrylic syrup containing 60% by weight of an acrylic resin having two or more ethylenically unsaturated groups, prepared by charging 200 g, dropping 500 g of methacrylic acid, and performing an addition reaction.

Examples 5 to 8 In a flask having a thermometer and a stirrer, 900 g of methyl methacrylate and 100 g of styrene, trimethylolpropane trimethacrylate (NK ester TMPT, Shin-Nakamura Chemical Co., Ltd.)
20 g, and 5.0 g of n-dodecyl mercaptan, a molecular weight modifier, was heated to 80 ° C., and 0.01 g of azobisisobutyronitrile, a polymerization initiator, was added.
Time reaction, viscosity 4.3poise (MN: 35000, MW: 50000)
0, MW / MN: 14.3).

Next, the same B component as in Examples 1 to 4 was added to the obtained A component (II) as shown in Table 1 to obtain respective acrylic syrup compositions.

Comparative Examples 1 to 3 A flask having a thermometer and a stirrer was charged with 800 g of methyl methacrylate, 200 g of styrene, and 5.0 g of ethylene glycol dimethacrylate (NK ester 1G, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name). After adding 5.0 g of dodecyl mercaptan and heating to 80 ° C., 0.01 g of azobisisobutyronitrile polymerization initiator was added, and the mixture was reacted at 90 ° C. for 9 hours, and had a viscosity of 4.5 poise (MN: 20000, MW: 45000, MW / M
N: 2.25) A component (III) was obtained.

Next, the same component B as in Examples 1 to 4 and a commercially available low-shrinking agent were added to the obtained component A (III) as shown in Table 1 to obtain respective acrylic syrup compositions. The commercially available low-shrinking agent used here is a polyvinyl acetate-based low-shrinking agent.

The following evaluations were performed on all of the obtained molded plates.

(Moldability) □ Transparency: Light transmittance (%) (Nippon Denshoku Industries Co., Ltd., N
D-101D) □ Cracks and sink marks:…: Not generated at all…: Generated on a part of the edge △: Generated on a part of the surface ×: Generated on the entire surface (300 hours boiling test) □ Whitening / yellowing:…: Not generated at all, transparent ○: Transparent △: Generated, but slightly transparent ×: opaque [Effect of the Invention] The present invention particularly reduces the shrinkage, improves the moldability,
Furthermore, it is an acrylic syrup composition which is excellent in boiling resistance while maintaining transparency.

Claims (1)

(57) [Claims] 1. An acrylic syrup composition comprising the following A component (80 to 20% by weight) and B component (20 to 80% by weight). (A) Component A: Acrylic obtained by adding 0.002 to 0.03 mol of a crosslinkable unsaturated monomer to the total number of moles of ethylenically unsaturated monomer having methyl methacrylate as a main component, and copolymerizing the same. Syrup has a weight average molecular weight (MW) of 2000
00 to 800,000, number average molecular weight (MN) is 2000 to 100,000,
Highly crosslinked acrylic syrup whose ratio (MW / MN) is 2 to 40. (B) Component B: an acrylic syrup containing an ethylenically unsaturated monomer and having 50 to 90% by weight of a vinyl ester resin or an acrylic resin having at least two or more ethylenically unsaturated groups in the resin.