JPS6279206A - Production of molded article of methacrylate resin - Google Patents

Abstract

PURPOSE:To obtain a molded article of a crosslinked resin having excellent physical properties such as heat-resistance, solvent-resistance, etc., without lowering the transparency of the resin, easily, by partly polymerizing a mixture of a resin raw material and a specific amount of a crosslinking agent and molding the partially polymerized mixture. CONSTITUTION:A mixture composed of (A) a resin raw material selected from an alkyl methacrylate monomer, an alpha,beta-ethylenic unsaturated monomer mixture composed mainly of an alkyl methacrylate and a syrup containing said polymer and (B) 2-250pts.wt. (based on 100pts. of the resin raw material) of a crosslinking agent (e.g. 1,3-propylene glycol dimethacrylate) is partly polymerized to obtain a molding material composed of a partly crosslinked gelatinous polymer having a total polymer content of <=80(wt)% and higher than the polymer content in the above mixture by 4-65%. The molding material is molded by injection molding, compression molding or transfer molding.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing methacrylic resin molded articles. More specifically, this article relates to a method for producing a methacrylic resin molded article to obtain a crosslinked molded article.

Conventional technology In general, methacrylic resins, whose main component is methyl methacrylate, are used in various fields such as lighting covers, automobile parts, signboards, ornaments, 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 for heat resistance is around 100°C.
At present, the demands from various fields that require heat resistance cannot be adequately met. 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, or 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 energy. Therefore, the development of methacrylic resins that can sufficiently withstand temperatures above the boiling point of water is expected.

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 for copolymerizing methyl methacrylate, α-methylstyrene and maleimide (Japanese Patent Publication No. 48-95.490Q'').

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 polymer cannot be obtained efficiently in a relatively short time. However, it has both advantages and disadvantages, such as the strong discoloration of the polymer and reduced transparency, weather resistance, surface hardness, mechanical strength, etc., making industrial production extremely difficult, and it has not yet been put into practical use. .

On the other hand, it is generally possible to improve heat resistance, solvent resistance, etc. by introducing a crosslinked structure into a linear polymer, but since the crosslinked polymer already has a three-dimensional structure, this crosslinked polymer It is impossible to mold the composite by injection molding, extrusion molding, or transfer molding. In addition, when molding is performed using the cast polymerization method, voids, foaming, etc. are likely to occur.
I! , not only cannot be molded, but also has the drawback of low productivity.

Kodama et al. reported in Koubunshi Kagaku Vol. 2 γ No. 291, p. 65 et al. 1 One way to improve the formability of cross-linked polymers is to use those with long distances between functional groups, and a considerable amount of monomer is present. For example, it is also possible to perform molding after the first stage polymerization has been completed (polymerization rate of 90% or more), and then perform the second stage polymerization to complete the polymerization. ”. However, there is no description of a specific example of this, and furthermore, according to the inventor's follow-up test based on the description by Kodama et al., when the sample was heated and compression molded in a mold after completing the first stage polymerization, the sample solidified, but It does not flow and becomes powder,
Shows no moldability at all. Therefore, the shaping described in Kodama et al. means a very simple bending process, and is not essentially the same as the shaping accompanied by flow, which is the object of the present invention.

Problems to be Solved by the Invention Therefore, an object of the present invention is to provide a novel method for manufacturing methacrylic resin molded articles. An object of the present invention is to provide a method for producing a crosslinked methacrylic resin molded article.

Another object of the present invention is to provide a method for producing a crosslinked methacrylic resin molded article that has excellent physical properties such as heat resistance and solvent resistance without reducing transparency.
A further object of the present invention is to provide a method for easily manufacturing crosslinked methacrylic resin molded articles having excellent physical properties such as heat resistance and solvent resistance without reducing transparency.

These materials were selected from the group consisting of (A) an alkyl methacrylate monomer, a mixture of α,β-ethylenically inert saturated monomers containing alkyl methacrylate as a main component, and a syrup containing a polymer thereof; Resin raw material and (B
) Partially polymerize a mixture consisting of 2 to 250 parts by weight of crosslinking agent per 100 parts by weight of the resin raw material, and reduce the polymer content to the above range such that the total polymer content does not exceed 80 parts by weight. It is characterized by molding a methacrylic resin molding material made of a partially crosslinked gel polymer with a polymer content increased by 4 to 65% by weight compared to the polymer content in the mixture by injection molding, compression molding, or transfer molding. It is rapidly produced by a method for producing methacrylic resin molded articles.

Means for Solving the Problems The monomers used as the resin raw material (A) in the present invention include alkyl methacrylate alone, alkyl methacrylate, and α,β-ethylenically inert saturated monomers that can be copolymerized with the alkyl methacrylate. A mixture of molecules is required. In the case of such a monomer mixture, the alkyl methacrylate is 50
The content is desirably mol% or more, and preferably 60 mol% or more. Alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n
Examples include -propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, and methyl methacrylate is particularly preferred.

As the copolymerizable monomer, other than the argyl methacrylate (e.g. methyl methacrylate) used as the main component, other alkyl methacrylates (e.g. the above-mentioned alkyl methacrylate, 2-ethylhexyl methacrylate,
lauryl methacrylate, cyclohexyl methacrylate, etc.), methyl acrylate, ethyl acrylate, n
-Propyl acrylate, isopropyl acrylate-1~
, n-butyl acrylate, 2-ethylhexyl acrylate, furkyl acrylate such as lauryl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, Hydroxy alkyl acrylates such as 2-hydroxy-3-chloropropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-chloropropyl methacrylate, etc. hydroxyalkyl methacrylate, acrylic acid,
Acrylates 1 such as methacrylic acid, neodymium acrylate, lead acrylate, boron acrylate, methacrylates such as neodymium methacrylate, lead methacrylate, boron methacrylate, vinyl chloride, vinyl acetate, acrylonitrile, methacrylateril, acrylamide , methacrylamide, styrene, α-methylstyrene, vinyltoluene, maleic anhydride, etc.

Furthermore, syrups containing a polymer of alkyl methacrylate or a monomer mixture containing alkyl methacrylate as a main component generally have a temperature of 1 to 20.0 at 25°C.
00 centibois viscosity, and 3 to 40 double star%,
Preferably, a monomer solution containing 6 to 20% polymer is used.

The crosslinking agent (B) used in the present invention is a monomer having at least two (meth)acryloyl groups in the molecule, and the number of atoms between the (meth)acryloyl groups is 10 or less. It is preferably represented by the following formulas (1) to (3) % formula % (1) [where n is an integer of 3 to 6, and MA represents a methacryloyl group. ] I R3 CM) 8-〇-CH2-C-G 0-()i) A・
... (2) (here FR+ is a group of H, CH3, C2R5 or CH20H, and R2 is H, CH3.

), or a CH20H group, R3 is H2CH
R+, R2 and R3 are not hydrogen at the same time, and (M)Δ represents a methacryloyl group or an acryloyl group. ] (M) AC-+CH2
It is a monomer represented by CH2 (E to h (M)... (3) (where 0 is 1 or 2).

Specific examples of these monomers include 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanethiol dimethacrylate, 1,3-butylene glycol dimethacrylate, and dimethacrylate. Methylolethane dimethacrylate,
1,1-dimethylolpropane dimethacrylate, 2,
2-Dimethylolpropane dimethacrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane dimethacrylate, ethylene glycol di(meth)acrylate and diethylene glycol Di (meta)
Examples include acrylate.

The amount of these crosslinking agents (B) used is the same as the resin raw material (A>
The amount is 2 to 250 parts by weight, preferably 4 to 150 parts by weight, per 100 parts by weight. That is, if it is less than 2 parts by weight, no improvement in the heat resistance of the final molded product will be observed, while if it exceeds 250 parts by weight, the final molded product will be brittle and cannot be put into practical use.

The methacrylic resin molding material according to the present invention is produced by polymerizing a mixture of the resin raw material (A) and a crosslinking agent (B) in the presence of a polymerization initiator, and then polymerizing the monomers present in the mixture. It consists of a gel-like partial polymer that is obtained by stopping the reaction when only a portion of the polymer reacts without the entire polymer reacting.

In this case, the content of the polymer present in the methacrylic resin molding material that is the hanging body for the gel-like part is (△) alkyl methacrylate monomer, α, β-ethylenic monomer mainly composed of argyl methacrylate. The polymer content in the mixture of the resin raw material 4 and (B) crosslinking agent selected from the group consisting of a saturated monomer mixture and a partial polymer thereof is 4 to 4.
The value increased by 65% by weight and does not exceed 80% by weight, preferably the value increased by 10 to 65% by weight and 80% by weight.
most preferably 20 to 65% by weight and not more than 80% by weight. If the above polymer content is less than 4% by weight, will the product be gel-like? If the value exceeds the upper limit of 65% or 80%, it will not show good flow during molding, both of which are not in accordance with the purpose of the present invention.

The polymer content in the partial polymer can be determined by an extraction method.

Various types of polymerization initiators can be used, but if a low-temperature active polymerization 1 initiator and a high-temperature active polymerization initiator are used together, the formation reaction of the gel-like partial polymer can be controlled by the low-temperature active polymer initiator. When the gel-like molding material thus obtained is then further heated and molded into a desired article, it can be effected by the action of the high temperature active polymerization initiator. However, it is also possible to use only one polymerization initiator, either a high temperature active initiator or a low temperature active initiator.

As the low-temperature active polymerization initiator, peroxide and azo compound radical polymerization initiators whose decomposition temperature is 50° C. or lower to obtain a half-life of 10 hours, for example, are preferable. In order to improve the storage stability of this molding material, it is preferable that the low-temperature active polymerization initiator disappears as much as possible during the polymerization process to obtain the molding material, so the temperature of the aforementioned component M is preferably 26 to 45°C.
Particularly preferred is 26 to 41°C. Further, the amount of the low-temperature active polymerization initiator used is 0.002 to 1%, preferably 0.002% to 1%, based on the combined amount of the resin raw material (A) and the crosslinking agent (B).
0.005 to 0.1 weight percent is used.

Examples of such low-temperature active polymerization initiators include (I)
Acetyl cyclohexyl sulfonyl peroxide, imbutyryl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, similystyl peroxydicarbonate, 2,2'- Azobis (4
-methoxy-2,4-dimethylvaleronitrile, (II
') di(2-ethoxyethyl) peroxydicarbonate, di(methoxyinpropyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, (III) di(3-methyl-3-methoxybutyl) peroxydicarbonate, t-butylperoxyneodecanoate, 2,2'-azobis(2,
Among these, compounds belonging to the groups (I> and (II) are preferable, and compounds belonging to the group (I>) are particularly preferable.

As a high temperature active polymerization initiator, the decomposition temperature is 60 to 220
A polymerization initiator such as peroxide at a temperature of 90 to 170 °C is preferable, and in order to improve the molding cycle and maintain storage stability,
C1 is a polymerization initiator which preferably has a decomposition temperature of 120 to 170°C. Further, the amount of the high temperature active polymerization initiator used is 0.02 to 2.0% by weight, preferably 0.05% by weight based on the total amount of the resin raw material (Δ) and the crosslinking agent (B).
~2.0% by weight is used.

Examples of such high temperature active polymerization initiators include (IV
) t-butylcumyl peroxide, diisopropylbenzene hydroperoxide, di↑-butyl peroxide, p-menthane hydroperoxide, 2,
5-dimethyl-2,5-di(t-butylperoxy)
Hexyne-3,1,1,3,3-tetramethylbutylhydroperoxide, 2,5-dimethylhexane-2
゜5-Sibide lobar oxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,
1.2.2-tetraphenyl-1,2-ethanediol, (V) 1,1-bis(t-butylperoxy)-3,
3,54-limethylcyclohexane, 1,1-bis(t
-butylperoxy)cyclohexane, t-butylperoxymaleic acid, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, cyclohexanone peroxide,
t'-butylperoxyinpropyl carbonate, 2
,5-dimethyl-2,5-di(benzoylperoxy)
Hexane, 2,2-bis(t-butylperoxy)octane, ↑-butylperoxyacetate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4, 4-bis(t-butylperoxy)valerate, di-t-butylshiba-oxyisophthalate, methyl ethyl ketone peroxide, α,α'-bis(t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5 -dimethyl 2,5-di(t-butylperoxy)hexane, (
VI) t-butyl hydroperoxide, m-toluoyl peroxide, benzoyl peroxide, t-
Butyl peroxyisobutyrate, 2,3-dimethyl-
2゜3-diphenylbutane, octanoyl peroxide, decanol peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid peroxide, acetyl peroxide, 1゜1' azobis (cyclohexane 1-carbonetrile) Among these, compounds belonging to the groups (Iv) and (V) are preferred, and compounds belonging to the group (IV) are particularly preferred.

As described above, the methacrylic resin molding material according to the present invention is produced by heating a mixture of the resin raw material (Δ) and the crosslinking agent B) in the presence of the polymerization initiator to polymerize it. This polymerization reaction is carried out at a temperature of 10 to 80°C, preferably 35 to 65°C.
-200 minutes, preferably 20-150 minutes. Therefore, 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 the high-temperature active polymerization initiator remains as it is without being decomposed at the reaction temperature. Therefore, it is consumed during the molding reaction using the molding material.

According to the present invention, a gel-like partial polymer having a desired polymerization rate can be obtained by stopping the polymerization reaction by quenching or the like. ) in the presence of the polymerization initiator, and by adding a specific amount of a specific regulator, it is possible to more easily produce a methacrylic molding material which is a gel-like polymer with a desired polymerization rate. Obtainable. Specific such modifiers include 1.4 (8>-o-menthadene, 2,6-dimethyl-2,4,6-octatriene,
There are 1,4-p-menthadene, 1,4 cyclohexadiene, and α-methylstyrene bipods.

Such a regulator is the resin raw material (A) and the crosslinking agent (B).
o, oooi to 0.5ii%, preferably o, oooi to 0.2% by weight, most preferably 0, based on the total amount of
．． It can be used in a range of 0.005 to 0.1%.

If the amount of the regulator added is less than 1,000% by weight, the regulating effect of the present invention is not exhibited, and if the amount added exceeds 0.5% by weight, the desired polymerization rate cannot be achieved.

According to the method of the present invention, the desired polymerization rate can be achieved by the addition of the regulator,
The low temperature active radical combination initiator can be adjusted by selecting the polymerization temperature.

That is, as the amount of the low-temperature active initiator is reduced, the polymerization rate becomes significantly slower at low polymerization rates. Furthermore, the larger the amount of the regulator is used, the slower the polymerization rate will be at a lower polymerization rate than when no regulator is used, and the time taken to reach that point will also be longer. Furthermore, the lower the polymerization temperature, the lower the polymerization rate and the slower the polymerization rate with the same formulation composition.

According to the method of the present invention, it is possible to obtain a gel-like polymer with a desired polymerization rate by stopping the polymerization reaction by rapid cooling during the process or by slowing down the polymerization rate by reducing the amount of a single polymer initiator. According to the second method of the present invention, it is possible to obtain a gel-like partial polymer with a desired polymerization rate with high availability and with a simpler operation, and in general, a gel-like partial polymer with good storage stability can be obtained. I can do that.

In addition, additives such as a chain transfer agent, a coloring agent, a filler, or other resins or other resins may be added to the raw material 11 mixture before polymerization in the gel-forming reaction by partial crosslinking, if necessary. For example, as a chain transfer agent, an alkyl having a carbon number of 11 to
12 n-alkyl and t-alkyl mercaptans,
Examples include thioglycolic acid and thioglycolic acid alkyl esters in which the alkyl has 11 to 8 carbon atoms. Further, as the colorant, any ordinary dye or pigment can be used. Further, fillers include glass fiber, calcium carbonate, methyl oxide, aluminum hydroxide, particulate carbon, carbon fiber, mica flakes, calcium phosphate, barium sulfate, magnesium oxide, tin oxide, and the like.

The methacrylic molding material according to the present invention is not sticky and has shape retention properties, so it can be handled in any shape such as a sheet, rod, block, or pellet. Since it flows by applying shear stress at room temperature or elevated temperature, it is possible to obtain products with complex shapes that cannot be achieved by cast polymerization. In particular, when the methacrylic molding material is crushed to an average particle size of 5 mm or less, preferably 2 mm or less, a slight shear stress may be applied during molding by injection molding, compression molding, etc. It exhibits extremely stable fluidity when used alone, and can flow into a predetermined shape to obtain a molded product that conforms to the mold.

As the injection molding method, compression molding method, or transfer molding method applied to the present invention, known equipment for the purpose can be applied. Depending on the mold shape of the article to be molded and the physical properties of the molding material used, the operating conditions range from 90 to 18
The temperature can be selected from 0'C, preferably from 100 to 150C, the molding pressure from 20 kg/cm to 5()OkCl/CIA, and the molding time from 1 to 30 minutes, preferably from 2 to 15 minutes. The molding material used in this invention decreases in volume as it polymerizes, so the mold used has
Preferably, the structure is such that the volume of the cavity can be reduced in the thickness direction as the volume shrinks.

Next, the present invention will be explained in detail with reference to Examples.

In the Examples, the polymer content of the partial polymer was measured by the following method.

In a Soxhlet extractor, add 1,000 ppm of hydroquinone methyl ether and dissolve it in dichloromethane.
50 ml of the above-mentioned gel-like polymer 15 () was put into a thimble for extraction in the form of strips, and reflux extraction was performed for 20 hours in a thermostatic water jar kept at 50'C. Thereafter, the extracted stream is poured into methanol (1, 2007) to separate the polymer, and the polymer is combined with the polymer in the filter paper and dried under reduced pressure at 55° C. until a constant weight is obtained, and the weight of the polymer is determined.

In addition, the abbreviations used in the examples are as follows.

PCNO cumyl peroxicine neodecanoate V-702
,2'-Azobis(4-methoxy-2,4-dimethylvaleronitrile) PBIB Tertiary-butylperoxyisobutyrate BP 1.1,2.2-tetraphenyl-1,2-
Ethanediol PBD Di-t-butyl peroxinide BC2,3
-dimethyl-2,3 -diphenylbutane V-401,1' Azobis(cyclohexane-1-carbonitrile) Example 1 Polymethyl methacrylate with an average degree of polymerization a, ooo
80 parts by weight (hereinafter referred to as "parts") of methyl methacrylate syrup containing 0% (hereinafter referred to as %) and 20 parts of neopentyl glycol dimethacrylate were mixed, and to this mixture, PCND O,005%, PAD O, 2%
, BCo, 01%, 1.4 (8) -p-Menthagene 0.01% was added, and two glass plates were separated at a distance of 1 om.
The mixture was injected into a cell assembled to a temperature of m, and the cell was put into a constant temperature water bath adjusted to 60° C., and after polymerization for 2.5 hours, it was taken out to obtain a gel-like partial polymer. The polymer content of the gel-like partial polymer was 32.5%.

325 g of this gel-like partial polymer was put into a pressable mold capable of obtaining the molded product shape shown in FIG.
Initial pressure 20kg/cm2.120 at mold temperature 130'C
After applying the pressure for 2 seconds, the pressure was increased to 85 parts M cm2 and maintained for 20 minutes, the mold was opened, and the molded product was taken out. The gel-like polymer filled the entire space of the mold, and a transparent molded product with a plate thickness of t3 mm and the same shape as the mold was obtained. The obtained molded product was heated to 130℃
The specimen was heated for 10 hours, and had a total light transmittance of 92.5% according to JIS K 7105, which showed excellent transparency, and the heat distortion temperature of this specimen according to ASTM D 64B was 142°C.

Example 2 PCN[)0.
005%, PBOo, 1%, and 1.4 (8)-D-mentagene o, oi% were mixed and dissolved, injected into a cell assembled with two glass plates with a spacing of 5 mm, and heated at 55°C in advance. The cell was put into a constant temperature water bath adjusted to 1 hour and 15 minutes, and a gel-like partial polymer was obtained. The polymer content of the gel-like partial polymer was 15.5%. This gel-like partial polymer 2450 was put into the same mold as in Example 1, and the mold temperature was 120°C and the initial pressure was 20k (1/Cm2
After 20 seconds, increase the pressure to 65 kg/cd and
The pressure was held for 0 minutes, the mold was opened, and the molded product was taken out. The gel-like polymer filled the entire space of the mold, and a transparent molded product with a plate thickness of 6 mm was obtained. The obtained molded product is 1
After heating at 30°C for 10 hours, the total light transmittance and heat distortion temperature were measured using the same measuring method as in Example 1, and found to be 92.7% and 141°C, respectively.

Example 3 PCND was added to a mixed liquid of 80 parts of methyl methacrylate syrup and 20 parts of neopentyl glycol dimethacrylate containing 9% of PMM△ with an average degree of polymerization of 13.000.
Mix and dissolve O, 0025%, PBD 0.2%, and BGo, 01%, inject into a cell assembled with two glass plates with a spacing of 5 mm, and place in a constant temperature water bath pre-adjusted to 60°C. A cell was charged and polymerization was carried out for 2.5 hours to obtain a gel-like partial polymer. The polymer content of the gel-like partial polymer was 62.5%. 325g of this gel-like partial polymer was put into the same mold as in Example 1, and the mold temperature was 140'C.
After applying an initial pressure of 45 k(]/Cm2 for 90 seconds, the pressure was increased to 8
The pressure was increased to 5 kg/cd, held for 15 minutes, the mold was opened, and the molded product was taken out. The gel-like polymer filled the entire space of the mold, and a transparent molded product with a plate thickness of 8 mm was obtained. The obtained molded product was heated at 130°C for 8 hours, and the total light transmittance and heat distortion temperature were measured using the same measurement method as in Example 1. They were 92.6% and 138%, respectively.
It was °C.

Example 4 To a mixed liquid of 80 parts of methyl methacrylate syrup containing 12% of polymethyl methacrylate having an average degree of polymerization of 12,000 and 20 parts of neopentyl glycol dimethacrylate, V-700,003% and Kayaester HTP-
65W (Product name, Kayaku Nouri Co., Ltd. Jaw Initiator>
0.05%, PH-22 (trade name, initiator manufactured by NOF Corporation) 0.1%, PBD O, 3%, 1.4 (8
)-p-Menthagene 0.008% was mixed and dissolved and injected into a cell assembled with two glass plates with a spacing of 5 mm, and the cell was placed in a constant temperature water bath adjusted to 55 ° C in advance. Polymerization was carried out for 2.5 hours to obtain a gel-like partial polymer. The polymer content of the gel-like partial polymer was 30%. 200 (l) of this gel-like partial polymer was put into the same mold as in Example 1, and the initial pressure was 20 kg/c at a mold temperature of 130°C.
m2 for 60 seconds, the pressure was increased to 150 kg/Cl1i, held for 5 minutes, the mold was opened, and the molded product was taken out. The gel-like polymer fills the cavity of the mold and has a plate thickness of 5.
A transparent molded article with a diameter of mm was obtained. 13 of the obtained molded products
After heating at 0'C for 10 hours, the total light transmittance and heat distortion temperature were measured using the same measuring method as in Example 1, and found to be 92.5% and 140°C, respectively.

Example 5 Polymethyl methacrylate with an average degree of polymerization of about a, ooo was
% of methyl methacrylate syrup and 10 parts of neopentyl glycol dimethacrylate.
CND O, 005%, PBDo, 3%, 1°4 (8)
1)-Mix and dissolve 0.01% of Menthagene, inject into a cell assembled with two glass plates with a spacing of 10 mm, and put the cell into a thermostatic water bath pre-adjusted to 60'C. Polymerize for .5 hours to obtain 1 gel-like partial polymer.
It's q. The polymer content of the gel-like partial polymer was 38%. 325g of this gel-like partial polymer was put into the same mold as in Example 1, and the mold temperature was 120°C and the initial pressure was 20kp/C.
After holding the pressure at m2 for 2 minutes, the pressure was roughly increased to 100 kM and held for 20 minutes, and the mold was opened to take out the molded product. The gel-like polymer filled the space of the mold, and a transparent molded product with a plate thickness of 8 mm was obtained. After heating the obtained molded article at 130°C for 10 hours, the total light transmittance and heat distortion temperature were measured using the same measuring method as in Example 1, and they were 92.8% and 123°C, respectively.

Example 6 PCNDo, 00
5%, PBDo, 2%, 1. 4 (8) Mix and dissolve 0.008% of -p-menthagene and prepare 60%
The cell was placed in a constant temperature water bath adjusted to 0.degree. C. and polymerized for -1 hour to obtain a gel-like partial polymer. The polymer content of the gel-like partial polymer was 25%. 1,200 kg of this gel-like partial polymer was put into a mold to obtain a box-shaped molded product as shown in Fig. 2, and the mold temperature was 130°C and the initial pressure was kept at 20 kg/cm2 for 1.5 minutes. After increasing the pressure to J/ci and holding the pressure for 20 minutes, the mold was opened and the molded product was taken out. A molded article was obtained according to the mold. After heating the obtained molded article at 130°C for 10 hours, the total light transmittance and heat distortion temperature were measured using the same measuring method as in Example 1. .5% and 136°C.

Example 7 The gel-like partial polymer of Example] was placed in the mold of Example 6 for 12 hours.
0q input, mold temperature 120℃, initial pressure 20kg/CIA
After holding the pressure for 2 minutes, the mold was opened and the molded product was taken out. The gel-like polymer filled the space of the mold to obtain a transparent molded product having an average thickness of about 4 mm.

Example 8 PCND 0.0 was added to the liquid mixture of 80 parts syrup of Example 1 and 20 parts ethylene glycol dimethacrylate.
Mix and dissolve 5%, PBDo, 2%, and 1.4 (8)-p-mentagene o, ooa%, and inject into a lath cell at intervals of 5 mm, and polymerize at 60°C for 1 hour to form a gel-like partial polymer. I took it out. This one has a polymer content of 18.2%
Made with gel-like partial polymer.

120 (] of this gel-like partial polymer was weighed, Example 6
Compression molding was performed using the same mold. Mold temperature 13
An initial pressure of 20k (J/Cm2) was applied for 30 seconds at 5°C, then the pressure was increased to 100k (1/cd) and held for 8 minutes, and the mold temperature was lowered to 110°C and taken out. The space of the mold was filled, and a molded product similar to that of the mold was obtained.

Example 9 80 parts of MMA monomer, 20 parts of neopentyl glycol dimethacrylate, 0 parts of 1.4(8)-p-mentadiene
．． 0.01 part of PCND, 0.0038 part of PCND, and 2 parts of PBDo were dissolved and mixed, and poured into a glass cell with a spacing of 10 mm.
The resulting product was polymerized at 0°C for 1.5 hours and taken out. This was an extremely soft gel-like partial polymer with a polymer content of 4%.

This gel-like partial polymer was compression molded using the mold of Example 6. Initial pressure 10kcl/ at mold temperature 130°C
After applying Cm2 for 1 minute, increase the pressure to 100kg/c.
The mold was held at M for 35 minutes, the mold temperature was lowered to 110°C, and the mold was taken out. The gel-like partial polymer flowed, and a transparent molded product similar to the mold was obtained.

Example 10 An injection molding machine for thermosetting resin (R large clamping force 100 to maximum injection force 2,000 k (1/ci) was equipped with an intrusible mold to obtain a molded product having the shape shown in Fig. 3, The material of Example 1 was fed into a feed hopper with a plunger, and while pressurizing the material with the plunger, the cylinder temperature was adjusted to 130 (l) by rotating the screw at room temperature, and the injection pressure cuff was adjusted to 00k (1/crA, After indexing is completed in 9.0 seconds, the inside of the cavity is sealed and the mold temperature is 130°C.
After leaving it for 0 seconds, the molding pressure was 38 kg/ci.
The pressure was held for seconds, the pressure was roughly held at 75 kg/cffl for 15 seconds, the pressure was then increased to 150 km and held for 15 minutes, the mold was opened, and the molded product was taken out. The partial gel polymer flowed into the sprue, runner, and gate of the injection mold, filling the inside of the cavity, and a transparent molded product having an average thickness of about 4 mm was obtained.

Example 11 A gel-like partial polymer with a polymer content of 19% was prepared by using the same recipe and the same method as in Example] and reducing the time by m.
It's q. This was molded in the same way as in Example 10, and 130 g was weighed by rotating the screw in the feed hopper. 30 at mold temperature 130℃
After being left for 2 seconds, the molding pressure was linearly increased to 75 kCI10 yf for 30 seconds, and then the molding pressure was kept at 15 QkQ/cm for 15 minutes. When the mold was opened and the molded product was taken out, the gel-like partial polymer filled the cavity and polymerized and hardened, yielding a transparent molded product with an average thickness of about 4 mm.

Example 12 The mold of Example 10 was molded into a pot-type transfer molding machine (maximum clamping force 100 tons, R large injection pressure 1,650 k).
]/crA), and a water passage groove was provided to cool the pot part to 40°C with cooling water. This pot part was filled with 130g of the material of Example 1, and the injection pressure was 700kCI/a.
After filling the material into the cavity at RT for 8 seconds, the mold temperature was 130° C. and the mold was left at an initial pressure of 20 kC1/cm for 30 seconds, and then the pressure was increased to 50 kfj/cffl and held for 30 seconds. Next, the pressure was linearly increased to 150 kg/cd in 30 seconds, and the pressure was held for 17 minutes, and then the mold was removed from the mold, and a transparent molded product similar to the mold was obtained.

Comparative Example 1 MMΔ monomer 80 parts, neopentyl glycol dimethacrylate 20 parts, PCND 0.004%, PBDo
, 2%, BCo, and 01% were mixed and melted, poured into a glass cell with an interval of 10 mm, and mixed at 60° C. for 3 hours. This product had a small coalescence content of 85.4%.

Using the mold of Example 1, the mold temperature was 135°C and the pressure was 1.
Compression molding was carried out at 40k(]/cm, but this partial polymer did not flow, and when it was taken out after 7 minutes, the entire part was crushed into particles the size of fine sand grains, and no molded product was obtained.

Comparative Example 2 In Example 3, 1.4 (81p-menthadene was 0.55
When polymerization was carried out by adding % to Afterwards, when the pressure was increased, most of it leaked out and overflowed.

After 10 minutes of reconversion, a thin sheet was obtained, but it remained uncured.

Comparative Example 3 80 parts of syrup from Example 4, 20 parts of neopentyl glycol dimethacrylate, PCND O, 004%, PB
2 parts of Do were mixed and dissolved, poured into a glass cell with an interval of 5 mm, polymerized at 60° C. for 2 hours, and then taken out.

The polymer content of this product was 74%. Using the mold of Example 1, the mold temperature was 135°C and the pressure was 140k (1/c
Compression molding was performed using RI, but this partial polymer did not flow, and when it was taken out in 1/14 inch mold, the mold was not filled with anti-greasing agent and was an incomplete molded product with fine cracks visible all over. Ta.

Comparative Example 4 An attempt was made to injection mold the partial polymer of Comparative Example 30 in the same manner as in Example 10, but during the rotation of the screw, the material in the cylinder began to polymerize and harden, causing the injection of gold into the cavity. It was not possible to fill it.

Effects of the Invention As described above, the present invention provides a syrup containing (△>alkyl methacrylate monomer, a mixture of α, β-ethylenic saturated monomers containing alkyl methacrylate as a main component, and a polymer thereof). A resin raw material selected from the group consisting of: and (B) 2 to 25 parts per 100 parts by weight of the resin I-Kyo material.
By partially polymerizing a mixture consisting of 0 parts by weight of a crosslinking agent, the polymer content is 4 to 65% lower than the polymer content in the mixture, provided that the total polymer content does not exceed 80,000%. This is a method for producing a methacrylic resin molded article, which is characterized in that a methacrylic resin molding material made of a partially crosslinked gel-like polymer with a weight of 50% is molded by an injection molding method, a compression molding method, or a transfer molding method. , it is possible to obtain products with complex shapes that cannot be achieved by cast polymerization. In particular, the molding material is not sticky and has shape retention properties, so it can be molded into any shape, and it is further crosslinked when molded by the molding method, so the heat resistance of the molded product is It is expensive and has excellent transparency.

[Brief Description of the Drawings] Fig. 1 is a perspective view showing an example of an article molded by the method of the present invention, and Fig. 2 is a partially cutaway perspective view showing an example of the article molded by the method of the present invention. 3 is a partially cutaway perspective view showing another example of an article molded by the method of the present invention. Patent applicant: Kyowa Gas Chemical Industry Co., Ltd. bit
1. Indication of the incident 1985 Patent No. 6'1 Application No. 216,152 February 2, Invention Name: Method for manufacturing methacrylic resin molded articles 3, Person making amendments 4, Agent

Claims (4)

[Claims] (1) (A) A resin raw material selected from the group consisting of an alkyl methacrylate monomer, an α,β-ethylenically unsaturated monomer mixture containing alkyl methacrylate as a main component, and syrup containing the polymer; B) Partially polymerize a mixture consisting of 2 to 250 parts by weight of a crosslinking agent per 100 parts by weight of the resin raw material to increase the polymer content in the mixture so that the total polymer content does not exceed 80% by weight. A methacrylic resin molding material made of a partially crosslinked gel-like polymer with a polymer content increased by 4 to 65% by weight over the polymer content of A method for manufacturing a resin molded article. (2) The method according to claim 1, wherein the alkyl group of the alkyl methacrylate has 1 to 4 carbon atoms. (3) The amount of crosslinking agent per 100 parts by weight of resin raw material is 4 to 15
0 parts by weight, and the content of the polymer is increased by 10 to 65% by weight compared to the polymer content in the mixture, as claimed in claim 1 or 2. The method described in. (4) The method according to claim 2, wherein the alkyl methacrylate is methyl methacrylate.