JPH02153913A - acrylic syrup composition - Google Patents

Abstract

PURPOSE:To obtain the title molding composition having small shrinkage factor, improved moldability, excellent transparency and boiling resistance by blending a specific highly crosslinked acrylic syrup with an acrylic syrup containing a vinyl ester resin. CONSTITUTION:(A) A highly crosslinked acrylic syrup which is obtained by copolymerizing (i) 1 total mol of an ethylenic unsaturated monomer consisting essentially of methyl methacrylate with (ii) 0.002-0.03mol crosslinkable unsaturated monomer and has 2 X 10<5>-8 X 10<5> weight-average molecular weight Mw, 2 X 10<4>-10<5> number-average molecular weight Mn and 2-40 ratio of Mw/Mn is blended with (B) an acrylic syrup containing 50-90wt% plural double bonds- containing vinyl ester resin or acrylic resin in a mixed solution of the components (i) and (ii) in the ratio of 80-20wt.% component A and 20-80wt.% component B to give the aimed composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an acrylic syrup composition for molding that has excellent transparency, low shrinkage, boiling resistance, and the like.

[Prior art and problems to be solved by the invention] Acrylic syrup compositions containing methyl methacrylate as a main component have excellent transparency and weather resistance, so they can be used for glass fiber reinforced boards, kitchen counters, wash basins, etc. used in In addition, recently, expectations have been growing that polyester can be used as a building material to replace polyester, and improvements in boiling resistance, heat resistance, impact resistance, etc. are desired.

Generally, as a method to improve the heat resistance of methacrylic resin, a method of copolymerizing α-methylstyrene (US
P 3,135.723), method of copolymerizing maleic anhydride (Japanese Patent Publication No. 45-31953, Japanese Patent Publication No. 49-1983)
10156), a method for copolymerizing methyl methacrylate, α-methylstyrene, and maleimide (Japanese Unexamined Patent Publication No. 1983
-95490) and many other methods.

However, although all of these methods improve heat resistance, they have drawbacks such as a significantly slow polymerization rate and a decrease in transparency, weather resistance, and boiling resistance of the polymer.

Furthermore, when these polymerization methods are used for acrylic wrinkles, the reaction during molding is slow due to the effects of crosslinkable unsaturated monomers remaining in the acrylic syrup, making it difficult to obtain molded products efficiently. There are many problems in making it a reality.

Among the physical properties of acrylic syrup, copolymerization with crosslinkable unsaturated monomers such as glycol diacrylate or dimethacrylate is an effective means to improve the boiling resistance and heat resistance in particular. In order for acrylic syrup to be moldable, the viscosity must be kept within a certain range.

As a result, the resin content in the acrylic syrup decreases, and when it is post-polymerized and molded, cracks and sink marks (partial wave-shaped depressions during molding) occur in the molded product, and the viscosity of the molded product decreases. If you try to increase the resin content while keeping it as high as possible, the molecular weight will decrease, resulting in poor boiling resistance, heat resistance,
It has the disadvantage that strength and impact resistance are extremely reduced.

Therefore, an object of the present invention is to provide an acrylic syrup composition that has particularly low shrinkage, improved moldability, maintains transparency, and has excellent boiling resistance.

[Means and effects for solving the problem] The present inventors,
As a result of intensive studies to solve the above problems, we have developed a resin that can be radically polymerized into a highly crosslinked acrylic syrup consisting of an ethylenically unsaturated monomer mainly composed of methyl methacrylate and a crosslinkable unsaturated monomer. It was discovered that the object of the present invention could be achieved by blending a resin having double bonds therein, and the present invention was completed.

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

(a) Component A: Add 0.002 to 0.03 moles of a crosslinkable unsaturated monomer to 1 total mole of ethylenically unsaturated monomers containing methyl methacrylate as the main component, and copolymerize. Of the acrylic syrup obtained by
M is 200,000 to 5oooooo, number average molecular weight (M
N) is 20,000 to 100,000, and the ratio (MW/M
A highly crosslinked acrylic syrup having a N ) of 2 to 40.

(b) Component B: a vinyl ester resin or acrylic resin having at least two or more double bonds in the resin,
50 to 90
Acrylic syrup containing % by weight.

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. This is an acrylic syrup composition for molding that maintains transparency and has excellent low shrinkage and boiling resistance, etc., by adding ester resin or acrylic resin.

The present invention will be explained in detail below.

First, the crosslinkable unsaturated monomer is added to 0.002 to 0.03 mol, preferably 0.01 to 0.00, per 1 total mole of ethylenically unsaturated monomers containing methyl methacrylate as a main component.
．． A highly crosslinked acrylic syrup (A) having a resin content of 10 to 50% by weight is obtained by copolymerizing the acrylic syrup (A) with a resin content of 10 to 50% by weight.

The method for producing this highly crosslinked acrylic syrup (A) is not particularly limited, but a polymerization initiator such as azobis-based or organic peroxide-based is added to the above monomer mixture, and if necessary, n
- Molecules such as dodecyl mercaptan and thioglycolic acid!
Add a regulator, heat polymerize between 60 to 120°C, and when the viscosity of the polymerization liquid reaches 2 to 6 pots, add a polymerization inhibitor and cool.
).

This highly crosslinked acrylic syrup (A) has a weight average molecular weight (?IW) of 200,000 to 800,000, a number average molecular weight (MN) of 20,000 to 100,000, and a ratio (MW
/MN) is 2 to 40, preferably 5 to 30.

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

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

Examples of crosslinkable unsaturated monomers include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1.
3-Butylene (licol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,6-hexanethiol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate) Acrylate, trimethylolpropane trimethacrylate, trimethylolethane triacrylate, trimethylolethane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethanetetraacrylate, etc. to obtain this crosslinkable acrylic syrup. For this purpose, polyethylene glycol dimethacrylate is particularly desirable.

The amount of the crosslinkable unsaturated monomer added is 0.002 to 0.03 mol per 1 total mole of the ethylenically unsaturated monomer. However, cross-linkable unsaturated monomers have a wide range of molecular weights (and many different numbers of double bonds in a molecule, so the amount of these added depends on the number of double bonds contained in one molecule). It is desirable to specify the number (n) of .

Expressed in general formula, the amount of crosslinkable unsaturated monomer having two or more double bonds in one molecule is 0.01/n to 0.0
6/nmol.

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

In the case of n-2, the usage amount is 0.005 to 0.03 mol, and in the case of n.3, the usage amount is 0.0034 to 0.0.
02 mol, in the case of n-4, the amount used is 0.0025
~0.015 mol.

If the amount of the crosslinkable unsaturated monomer added is less than 0.002 mol, the crosslinking density of the acrylic syrup is too low;
The highly crosslinked acrylic syrup that is the object of the present invention cannot be obtained. Furthermore, if the amount exceeds 0.03 mol, it is difficult to control the temperature during copolymerization, and runaway is likely to occur, and even if copolymerization is carried out, the degree of polymerization will be low. Too small to be used as a molding material.

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

These vinyl ester resins are contained in a mixed solution of 50 to 90% by weight of an ethylenically unsaturated monomer and a crosslinkable unsaturated monomer mainly composed of methyl methacrylate, and have a viscosity of 3 to 100 poise. It is used as an acrylic syrup in some places.

On the other hand, regarding acrylic resin, for example,
19601, a glycidyl group-containing monomer is copolymerized in an acrylic resin, and this is then mixed into an ethylenically unsaturated monomer containing a monomer that is reactive with the glycidyl group. Viscosity 3 containing 50 to 90% by weight in the resin and reacting 1 to 100% of the glycidyl groups in the resin.
An ethylenically unsaturated monomer that is reactive with a glycidyl group is copolymerized in an acrylic syrup or acrylic resin having a poise of ~100 poise, and a glycidyl group-containing ethylenically unsaturated monomer is reacted with this by 1 to 100%. It is used as an acrylic syrup with a viscosity of 3 to 100 poise.

These acrylic syrups were mixed with the above-mentioned highly crosslinked acrylic syrup (component A), and the total amount was 100% by weight.
shall be.

The amount of the crosslinkable unsaturated monomer contained in the mixed acrylic syrup is 1 to 30% by weight, preferably 3 to 2%, when the A component and B component are mixed.
It is 1%. If it is less than 1% by weight, the boiling resistance will be insufficient, and if it exceeds 30% by weight, the originally aimed effect of low shrinkage may be impaired, which is not preferable.

The mixing amount of component A and component B depends on the resin content contained in each of the highly crosslinked acrylic syrup and acrylic syrup used, but it is preferably A component/B component -20,780 to 80/20.

Generally, when a different type of resin is mixed as a low shrinkage agent, transparency tends to decrease and become cloudy, but when component A obtained in the present invention is used, transparency is not impaired.

In addition, the A component obtained by the present invention tends to be difficult to stir and mix alone, but when mixed with the B component, it can be easily stirred and mixed. In particular, when an inorganic filler is used, it is less likely to increase the viscosity compared to ordinary acrylic syrup, and a high filler content can be achieved.

The acrylic syrup composition obtained in the present invention is blended with additives such as inorganic fillers, other fillers, coloring agents such as pigments and dyes, polymerization initiators, and polymerization accelerators as necessary, and molds, It is injected into a mold such as a resin mold or a glass mold, and cured under pressure or normal pressure, by heating or at room temperature, to obtain an astronomical stone-like molded product.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Examples 1 to 4 In a flask equipped with a thermometer and a stirrer, 55 g of methyl methacrylate looog and polyethylene glycol dimethacrylate (NK Ester 9G, manufactured by Shin Nakamura Kagaku ■, trade name) were added.
and the molecular weight regulator n-dodecyl mercaptan5.
After adding 0g of azobisisobutyronitrile and heating it to 80°C, 0.01g of azobisisobutyronitrile, a polymerization initiator, was added, and the reaction was carried out at 90°C for 5 hours, resulting in a viscosity of 4.5poise (MN
:42000. MW:450000. MW/MN: 10
．． Component A (I) of 7) was obtained.

Next, component B was added to the obtained component A (1) as shown in Table 1 to obtain each acrylic syrup composition.

Examples 5 to 8 A flask equipped with a thermometer and a stirrer was charged with 900 g of methyl methacrylate, 100 g of styrene, and 20 g of (NK ester IG manufactured by Shin Nakamura Chemical, trade name), and molecular weight modifier n.
- Add 5.0 g of dodecyl mercaptan and heat to 80°C, then add polymerization initiator azobisisobutyronitrile 0°01
g and reacted at 90°C for 7 hours, resulting in a viscosity of 4.
．． 3poise (MN:35000.MW:5000
00. Component A (II) with Mll/MN: 14.3) was obtained.

Next, component B was added to the obtained component A (II) as shown in Table 1 to obtain each acrylic syrup composition.

Comparative Examples 1 to 3 In a flask equipped with a thermometer and a stirrer, 800 g of methyl methacrylate and 200 g of styrene were placed in a flask equipped with ethylene glycol dimethacrylate (NK Ester IG, manufactured by Shin Nakamura Chemical Co., Ltd.).
(Product name) 5.0g, added 5.0g of molecular weight regulator n-dodecyl mercaptan, heated to 80°C, added 0°01g of polymerization initiator azobisisobutyronitrile, and heated to 90°C. After 9 hours of reaction, the viscosity was 4.5p.
oise (MN:20000.MW:45000',
A component (III) with MW/MN: 2.25) was obtained.

Next, component B and a commercially available low shrinkage agent were added to the obtained component A (II[) as shown in Table 1 to obtain each acrylic syrup composition.

All of the obtained molded plates were evaluated as follows.

(Moldability) Transparency: Light transmittance (manufactured by Nippon Denshoku Kogyo ■, ND-10
1 [1] Cracked mouth/sink: ◎ - - Not occurred at all 0 - - Occurred on a part of the green Δ - Occurred on a part of the surface × - Occurred on the entire surface (300 hour boiling test ) Mouth whitening/yellowing: ◎--No appearance occurred and the mouth was transparent.
-.It was transparent. This is an acrylic syrup composition that has improved boiling resistance and maintains transparency.

Written amendment (method) % formula % 1. Indication of the case Patent Application No. 307600 of 1988 2. Name of the invention Acrylic syrup composition 3. Person making the amendment Relationship to the case Patent applicant address Kasumigaseki, Chiyoda-ku, Tokyo 3-chome 2-5 name (
312) Mitsui Toatsu Kagaku Co., Ltd. Representative: Sawamura Peio 4, Agent address: 7th floor, Midoriya 2nd Building, 3-7-3 Shinbashi, Minato-ku, Tokyo 105 Contents of amendment (1) Attachment of power of attorney Replenish as per below.

(2) Print out the entire statement as shown in the attached sheet.

(No change in content)

Claims (1)

[Scope of Claims] 1. An acrylic syrup composition comprising 80 to 20% by weight of component A and 20 to 80% by weight of component B. (a) Component A: 0.002 to 0.03 mole of crosslinkable unsaturated monomer is added to 1 total mole of ethylenically unsaturated monomer mainly composed of methyl methacrylate, and copolymerized. Of the acrylic syrup obtained by
W) is 200,000 to 800,000, number average molecular weight (M
N) is 20,000 to 100,000, and the ratio (MW/M
A highly crosslinked acrylic syrup in which N) is 2 to 40. (b) Component B: A vinyl ester resin or acrylic resin having at least two or more double bonds in the resin, an ethylenically unsaturated monomer whose main component is methyl methacrylate, and a crosslinkable unsaturated monomer. Acrylic syrup containing 50 to 90% by weight in the mixture with.