JPS63193810A - Manufacture of large-sized resin molded body - Google Patents

Abstract

PURPOSE:To provide a large-sized molded product to which a mold surface whose surface and inside are free from a hollow and void distortion is transferred in a comparatively short period of time, by a method wherein a raw material solution mainly composed of vinyl monomer containing a polymer or not containing the polymer is cast within a mold frame, which is polymerized and cured under heating and pressurization. CONSTITUTION:Raw material solution mainly composed of a vinyl monomer containing a polymer or not containing a polymer has a monomer composition obtained by making use of a vinyl monomer or a vinylidene monomer mainly or a monomer composition into which a polymer which is meltable into the monomer exists in a molten state as its main agent. A material containing a polymerization initiator and various auxiliary agents or additive agents such as a polymerization accelerator are mixed up with the main agent all together or separately, and the same is molten. Raw material solution like this is cast within a mold frame and cured through polymerization under heating and pressurization, a large-sized molded product, which has little hollow on the surface or little foaming and void distortion on the inside and is excellent from an external appearance and functional points of views, can be molded in a short period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a large-sized molded article of vinyl resin by cast polymerization.

<Prior Art> In general, many molded products of vinyl resins obtained from vinyl monomers are on the market, whether for household or industrial use.

Vinyl resins are molded by melting and softening polymers in the form of powders, beads, pellets, sheets, etc. at high temperatures, and using methods such as injection molding, compression molding, and thermoforming.

On the other hand, there is a casting polymerization method in which a vinyl monomer is directly polymerized and cured into the shape of a molded article to be obtained.

A known method is to use methyl methacrylate or ethylene glycol bisallyl carbonate t- as the monomer and slowly polymerize it in a glass mold, usually for several hours or more, to obtain methacrylic resin plates and eyeglass lenses. ing.

JP-A-60-258219, JP-A-61-207
No. 408, etc., proposes a disk base obtained by polymerizing and curing in a mold using methyl methacrylate or a styrene monomer.

In these conventional cast polymerization methods, components such as a monomer and a polymerization initiator are mixed all at once, and the mixture is poured into a mold and polymerized.

<Problem to be solved by the invention> In order to obtain large molded products by melt molding such as injection molding, vinyl polymers have a high viscosity even in the molten state, so it is especially difficult to inject them into a mold. Requires high temperature and pressure.

These polymers generally undergo thermal decomposition and deterioration at high temperatures.

Furthermore, compression molding and thermoforming, in which plate-shaped vinyl polymers are softened and molded, have poor processability, and there are limits to their applicability to complex shapes.

Furthermore, due to the high viscosity of molding using such polymers, there is a limit to its application to large molded products or molded products that require precise transfer of the mold surface, and in many cases requires large costs and advanced technology. In addition, internal distortion is large, and deformation and performance deterioration are likely to occur.

On the other hand, it takes a long time to obtain a product by cast polymerization from a raw material liquid mainly containing vinyl monomers because the raw material liquid undergoes heat generation and volumetric contraction during polymerization.

JP-A-60-258219, JP-A-61-207
In the case of thin and relatively small disks such as those disclosed in Publication No. 408, there are few surface sinks, internal voids, or distortions due to foaming due to heat generation or volumetric contraction, but this method is not suitable for producing large molded objects in a short time. becomes a big problem.

An object of the present invention is to provide a large-sized molded product whose mold surface is accurately transferred without dents, voids, distortions, etc. on the surface or inside in a relatively short time.

Means for Solving the Problems The present invention is characterized by using a raw material liquid mainly consisting of a vinyl monomer containing or not containing a polymer, injecting it into a mold, and polymerizing and curing it under heat and pressure. This is a method for manufacturing a large resin molded body.

The raw material liquid mainly composed of vinyl monomers containing or not containing polymers used in the present invention refers to monomer compositions mainly containing vinyl monomers or vinylidene monomers, or monomer compositions containing mainly vinyl monomers or vinylidene monomers, or The main ingredient is a monomer composition in which a soluble polymer is dissolved, and it contains a polymerization initiator, and if necessary, various auxiliaries and additives such as a polymerization accelerator may be added together or They are mixed and dissolved separately.

The vinyl monomer used as the main component of the reactive raw material liquid in the present invention refers to a monomer having at least one polymerizable unsaturated carbon bond in the molecule, and specifically, (meth) Methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isopropyl (meth)acrylate, isobornyl (meth)acrylate, bornyl (meth)acrylate, cyclohexynol (meth)acrylate, (meth)acrylate dicyclopentanyl acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate,
C1-25 aliphatic alcohols, alicyclic alcohols, heterocyclic alcohols, aromatic alcohols or phenols, halogen-containing aromatic alcohols or phenols, such as tribromophenyl (meth)acrylate, furfuryl (meth)acrylate, etc. acrylic esters and methacrylic esters; or aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, p-bromustyrene: acrylonitrile, methacrylonitrile, crotonitrile, etc. Vinyl nitriles: Vinyl esters such as vinyl acetate: Metal salts of (meth)acrylates such as copper (meth)acrylate, neodymium (meth)acrylate, and lead (meth)acrylate Niacrylic acid, methacrylic acid, and maleic acid , unsaturated carboxylic acids such as maleic anhydride: N-phenylmaleimide, N-)lylmaleimide, N-cyclohexylmaleimide, N-0-bromphenylmaleimide,
Examples include maleimides such as N-ethylmaleimide.

The selection of the vinyl or vinylidene monomer is determined by the desired performance of the polymer.

For example, in a molded article that requires heat resistance, monomers whose polymer glass transition temperature is high may be mainly selected.

Examples of such monomers include isobornyl (meth)acrylate, bornyl (meth)acrylate, phenyl (meth)acrylate, fentyl methacrylate, and (meth)acrylate.
Dicyclopentanyl acrylate, (meth)acrylic acid 1
-adamancune, 3.5 dimethyladamancune (meth)acrylate, α-methylstyrene, N-phenylmaleimide, N-tolylmaleimide, N-(O-chlorophenyl)maleimide, maleic anhydride, methacrylic anhydride, etc. .

In addition, for example, in molded products that require low humidity,
The monomer selected from among aliphatic alcohols having 6 to 25 carbon atoms, alicyclic alcohols, aromatic alcohols, or (meth)acrylic acid esters with phenols and aromatic vinyl compounds may be mainly selected.

Examples of such monomers include alcohols having 6 to 25 carbon atoms or phenols such as phenol, benzyl alcohol, cyclohexanol, 4-methylcyclohexanol, 2,2°5-trimethylcyclohexanol, 2-adamantanol, and 3-methylcyclohexanol. Methyl-1-adamantanol, 3-ethyladamantanol, p-menthanol-8, p-menthanol-2, octahydro-4,7
Examples include methacrylic acid esters with -menthafinden-1-ylmethanol, isoborneol, 2-methylcamphanol, l-menthanol, etc., and aromatic vinyl compounds such as styrene, α-methylstyrene, and vinyltoluene.

In addition, in the case of a molded article requiring a higher refractive index, the material may be mainly selected from aromatic alcohols or phenols, (meth)acrylic acid esters with halogen-containing aromatic alcohols or phenols, or aromatic vinyl monomers.

Examples of such monomers include phenyl (meth)acrylate, benzyl (meth)acrylate, phenethyl (meth)acrylate, p-bromphenyl (meth)acrylate, p-chlorophenyl (meth)acrylate, (meta)
Tribromphenyl acrylate, (meth)acrylic acid-
p-Brombenzyl, styrene, α-methylstyrene,
Examples include p-chlorostyrene and p-bromstyrene.

In particular, from the viewpoint of polymerization curability and transparency, it is preferable to mainly use at least one selected from monomers containing acryloxy groups and methacryloxy groups in the molecule, and aromatic vinyl compounds.

Such vinyl monomers can be used alone or in combination, and other copolymerizable monomers can also be used in combination.

Such other copolymerizable monomers include unsaturated amides such as acrylamide and methacrylamide, nigericidyl (meth)acrylate, 2-hydroxyethyl (meth)
Examples include acrylate, diaminoethyl (meth)acrylate, and the like.

Such other copolymerizable monomers can be used within a range that does not adversely affect the performance of the polymer, but are usually used in an amount of 50% by weight or less relative to the vinyl monomer.

In addition, in the present invention, in order to further improve the strength and chemical resistance of the molded article, it is possible to use a polyfunctional unsaturated monomer having at least two or more polymerizable unsaturated carbon bonds in the molecule. can.

Examples of such polyfunctional unsaturated monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and nonaethylene glycol di(meth)acrylate. meth)acrylate, tetradeoxyethylene glycol di(meth)
Ethylene glycol, such as acrylate, or its oligomer, whose both terminal hydroxyl groups are esterified with acrylic acid or methacrylic acid; neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, butanediol di(meth)acrylate, etc. Those in which the hydroxyl groups of other dihydric alcohols are esterified with acrylic acid or methacrylic acid; bisphenol A or bisphenol-alkylene oxide adducts, or halogen-substituted products thereof, with both terminal hydroxyl groups esterified with acrylic acid or methacrylic acid. Polyhydric alcohols such as trimethylolpropane and pentaerythritol are esterified with acrylic acid or methacrylic acid; and epoxy groups of glycidyl acrylate or glycidyl methacrylate are added to the terminal hydroxyl groups of these dihydric alcohols or polyhydric alcohols. Ring-opening addition; Ring-opening addition of the epoxy group of glycidyl acrylate or glycidyl methacrylate to dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, or their halogen-substituted products, or their alkylene oxide adducts. Examples include aryl methacrylate, divinylbenzene, etc.

The polyfunctional unsaturated monomer can be used in an amount of 30% by weight or less in the monomer composition.

If it exceeds 30% by weight, polymerization tends to be non-uniform, internal distortion becomes large, and it becomes difficult to maintain mechanical strength, which is not preferable.

The vinyl monomer used in the present invention can be used as a monomer, but it is also useful to use it as a liquid partially containing a polymer in terms of polymerization curability and handling properties.

A liquid partially containing a polymer can be prepared by a known method such as dissolving a polymer in a monomer or prepolymerizing a monomer.

The amount of the polymer is up to about 40% by weight, and may be adjusted depending on the upper limit of the viscosity of the liquid.

The viscosity of the liquid depends on handling, flowability into the formwork,
Furthermore, from the point of view of transferability of minute shapes such as molds, 10 to 5
Preferably it is oooo centipoise.

With the 10 cm void groove, the flowability into the mold is good, but the shrinkage and heat generation due to polymerization and hardening of the raw material liquid are large, and voids are likely to occur inside the product, and by-products and decomposition due to thermal decomposition There are many things, and 500
When the void size exceeds 0.00 cm, air bubbles caught during mixing are difficult to escape, and fine transfer of the formwork is likely to be sufficient.

A polymerization initiator is used in the present invention.

Specific examples include diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, and disuccinic acid peroxide; dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide; Peroxy esters such as butyl peroxyacetate, t-butyl peroxy pivalate, t-butyl peroxybenzoate, and t-butyl maleic acid hemiperester; Hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide : Organic peracids such as ketone peroxide such as methyl ethyl ketone peroxide, and azo compounds such as 2,2-azobisisobutyronitrile and 2,2-azobis(2,4-dimethylvaleronitrile). It will be done.

In the present invention, it is preferable to mainly use a polymerization initiator whose temperature in the 10 o'clock time range is 50° C. or higher.

It is preferable to mainly use a polymerization initiator having a temperature in the 10 hour range of less than 50°C.

If it is mainly used as a polymerization initiator with a temperature in the 10 hour range of less than 50°C, there is a problem that polymerization tends to proceed during storage, which is not preferable.

The polymerization initiator is 0.0 parts by weight per 100 parts by weight of the monomer composition.
It is used in an amount of 1 to 10 parts by weight.

A sufficient reaction rate can also be obtained by appropriately setting temperature conditions depending on the combination of monomer and polymerization initiator.

Furthermore, in order to increase the reaction rate or keep the temperature low, in addition to the above-mentioned polymerization initiator, a polymerization accelerator and auxiliary components of the polymerization accelerator can also be used. Auxiliary components of the polymerization accelerator include metal-containing organic compounds, amines, and halogen compounds of amines.

Such reducing substances as polymerization accelerators include lauryl mercaptan, octyl mercaptan, 2-ethylhexyl, mercaptan, glycol dimercaptoacetate,
Examples include mercaptans such as glycol mercaptopropionate, thioureas such as dibutylthiourea, tetramethylthiourea, nitrimethylphosphite, and phosphite esters such as tri-n-butylphosphite.

Examples of the metal-containing organic compound include organic acid salts of metals selected from iron, copper, cobalt, nickel, tin, aluminum, palladium, and antimony, or organic complexes.

In addition, as amines or halogen compounds of amines,
-class amines, secondary amines, tertiary amines, hydrogen halides thereof, and quaternary ammonium halides.

In order to increase the reaction rate and complete polymerization, combinations of polymerization initiators, polymerization promoters, and their auxiliary components include peroxyesters as polymerization initiators, mercaptans, thioureas, and polymerization promoters as polymerization promoters. As an auxiliary component of the accelerator, a combination of a hydrogen halide salt of an amine or a quaternary ammonium halide and a copper-containing compound, hemiperesters among peroxyesters as a polymerization initiator, mercaptans as a polymerization accelerator,
As an auxiliary component of the polymerization accelerator, a combination of an amine or a halogen compound of an amine and an organic compound containing tin, aluminum, or antimony is preferred.

The amount of such polymerization accelerator and auxiliary components of the polymerization accelerator is 0.00001 to 1% by weight based on 100 parts by weight of the monomer composition.
Use within the range.

A polymerization initiator, a polymerization accelerator, and their auxiliary components can be added all at once or sequentially to the monomer composition and mixed to form a raw material liquid.
A method is adopted in which a raw material solution containing a polymerization initiator and a polymerization accelerator are separately prepared as part of the monomer composition, and mixed immediately before pouring into the mold. is preferred.

The auxiliary component of the polymerization accelerator can be used by being added and dissolved in either the raw material liquid containing the polymerization initiator or the liquid containing the polymerization accelerator.

In addition, an ultraviolet absorber, a heat stabilizer, a lubricant, a mold release agent, and a coloring agent can be added to the raw material liquid as necessary.

It is preferable to mix the raw material liquids at a temperature of 50° C. or lower and for a time shorter than 10 minutes.

If the temperature during mixing is higher than 50°C, polymerization will partially proceed during mixing, which is not preferable.

Moreover, if the mixing time is long, polymerization will proceed during mixing, which is undesirable.

The shorter the mixing time, the better, as long as sufficient mixing is achieved.

As for the mixing method, to mold small molded bodies, it is possible to mix the raw material liquid in a batch method and then pour it into a mold, but this method is difficult to mold large molded bodies.

A method in which the raw material liquid is continuously mixed and injected into the mold is preferred because a large molded body can be molded and uniform mixing is easy.

In any case, it is desirable that the time from mixing to injection be as short as possible.

For feeding the liquid to the mixer and subsequently injecting it into the mold, a general-purpose liquid feeding device that can pressurize and has quantitative properties, such as a piston pump or a gear pump, is used.

Continuous mixing can be performed by a well-known and commonly used liquid mixing method using an impingement mixer, dynamic mixer, static mixer, or the like.

The closer these mixers are to the formwork, the better.

In the present invention, compared to the conventional molten resin injection molding method, the injection pressure may be lower because the raw material liquid used as the molding material has a lower viscosity than the molten resin.

As the mold, metal molds, resin molds, rubber molds, wooden molds, etc. can be used, but metal molds are particularly preferred in terms of accuracy and durability.

The formwork can be heated using known methods such as heater heating by embedding a heater in the formwork, cooling by air cooling, or adding a jacket or passage for a heat medium to the formwork or passing hot water or heat medium oil through it. It is done.

The pressure inside the mold can be applied using a mold structure that can reduce the volume of the space filled by injecting the raw material liquid into the mold using an external force, for example, JP-A-60-97815, Publication No. 60-212318, JP-A-59-1069
39, the method described in the publication, etc., or the method of introducing compressed fluid such as compressed air from the outside into the raw material liquid in the mold, for example, the method described in JP-A-56-146743, etc. Any known method may be used.

The temperature of the formwork is about 50 to 150℃, and even 70℃.
A range of 120°C to 120°C is preferred.

At temperatures below 50°C, it takes a long time for polymerization and curing, and at temperatures above 150°C, it becomes difficult to control the heat generated by polymerization, which is undesirable because decomposition and foaming are likely to occur and distortions are likely to remain.

As for the pressurizing conditions, during polymerization and curing, it is preferable to pressurize the reactive raw material in the mold at a maximum pressure of 1 to 100 kir/aj, and more preferably a maximum pressure of 10 to 50 kg/aj. .

Further, the pressure can be increased as the reaction progresses, and the pressure can be lowered arbitrarily after the reaction is completed.

If the pressure is less than Lkg/-, the mold cannot be transferred sufficiently due to contraction of the raw material liquid during polymerization and curing, and voids and surface dents are likely to occur in the product, making it impossible to accurately transfer the mold. In addition, bubbles are likely to occur due to vaporization of the monomer.

Pressures exceeding 100 kg/d are not preferred because distortions due to compressive stress tend to remain in the molded product.

Further, after curing, heat treatment can be performed at a temperature equal to or higher than the glass transition temperature of the polymer in order to reduce internal distortion.

The polymerization time according to the method of the present invention can be shortened to 10 minutes or less by selecting conditions such as the type and concentration of the polymerization initiator and the polymerization accelerator, and the temperature of the mold.

As a large-sized resin molded product, it can be applied to products of all shapes and sizes by changing the mold.

The present invention can be applied to large molded products that are difficult to mold using melt molding methods.

Examples include automobile glazing parts such as sunroofs, side windows, rear windows, triangular windows, etc.; automobile exterior decorative parts such as rear panels, center pillars, rear pillars, front grills, etc.; house fixtures and decorations. Bathtub, concentrating solar collector,
These include lighting domes, door materials, window materials, partition materials, table tops, bathroom vanities, counter tops, signboards, display boards, etc.

<Effects of the Invention> According to the present invention, a polymerization initiator and the like are added to a raw material liquid mainly composed of vinyl monomers, mixed uniformly, and then immediately poured into a mold and heated and pressurized to polymerize and harden. As a result, although it is a large molded product, there are few surface dents, internal foaming, and void distortion, and it has excellent appearance and performance, and can be molded in a short time of about 10 minutes or less.

<Example> The present invention will be explained below using examples.

In this example, the raw material liquid is pressurized by a piston pump operated by hydraulic pressure through piping from each raw material liquid tank, and guided to the collision mixer attached to the mold. The raw material liquid is injected into the mold while colliding and mixing under high pressure.

After the injection is completed, the raw material liquid outlet of the mixer is shut off, and the slideable core member that forms one side of the mold cavity is slid by hydraulic pressure, reducing the space volume of the part of the cavity. A mold with a structure that pressurizes the raw material liquid was used.

In addition, as a performance evaluation of the obtained molded product, the total light transmittance and haze value were determined according to ASTM D-1003, the residual upper layer was determined by gas chromatography using an extract, and the heating deformation temperature was determined according to ASTM D-1003. 648.

Example 1 (Preparation of raw syrup) 600 g of methyl methacrylate, 1300 g of dicyclopentanyl methacrylate, and 0.2 g of azobisisobutyronitrile were prepolymerized in a reaction vessel with stirring at 60°C, and the viscosity was slightly reduced. When the temperature rose, it was rapidly cooled to prepare a viscous solution of raw syrup.

The viscosity was 10 voids.

(Preparation to raw material solution) For 900 g of raw syrup, 100 g of tetradeoxyethylene glycol dimethacrylate, 10 g of 2-merutoethanol, and 1 g of a 1% by weight metal methacrylate solution of copper naphthenate (Cu content 10%). was added and mixed uniformly to prepare raw material liquid A.

The viscosity (25°C) was 8 voids.

(Preparation of raw material liquid B) 15 g of t-butyl peroxybenzoate and 1 g of dimethyloctylamine hydrochloride for raw syrup looog
was added and uniformly dissolved to prepare raw material liquid B.

The viscosity (25°C) was 10 voids.

(Cast molding) Has a radius of curvature of 2000, 600 x 600 fin size, lo
Using a mold having the shape of a sunroof for an automobile with a thickness of am, raw material liquid A and raw material liquid B were mixed at a weight ratio of 1:1 and placed in the above-mentioned mold whose temperature was adjusted to 70°C for 7 seconds. Injected.

Gradually pressurize the raw material liquid in the mold so that a pressure of 20 + r / c + J is applied to the raw material liquid 7 minutes after liquid injection, then reduce the pressure, and open the mold 10 minutes after liquid injection. A cured sunroof molded article was obtained.

(Performance of molded product) The obtained sunroof molded product has a total light transmittance of 93.0%.
The molded product had excellent transparency with a haze value of 0.5%, and an excellent appearance with no defects such as voids inside sink marks on the surface.

In addition, the residual monomer in the molded product is as low as 0.8%.
The heat deformation temperature was as high as 135°C, and even after being eroded in ethanol for 1 hour, no cranking occurred, and the molded product was suitable as an automobile glazing part.

Example 2 (Preparation of raw syrup) To 1400 g of methyl methacrylate, methacrylic resin (
Sumipex-B? llI (manufactured by Sumitomo Chemical Co., Ltd.) 6
00g was dissolved to prepare raw syrup.

The viscosity (25°C) was 10 voids.

(Preparation of raw material liquid C) To 900 g of raw syrup, 100 g of trimethylolpropane trimethacrylate and 10 g of glycol dimercaptoprobionate were added and mixed uniformly.
was prepared.

The viscosity (25°C) was 8 voids.

(Preparation of raw material liquid) To 1000 g of raw syrup, 20 g of t-butylmaleic acid hemiperester, 1.5 g of dimethyloctylamine hydrochloride, and 1 g of acetylacetone-tin complex were added and uniformly dissolved to prepare a raw material liquid. .

The viscosity (25°C) was 10 voids.

(Cast molding) Average thickness is 3 Tsuru, medium 30 Dragon rep (rising part)
300X800■-large car rear with
Using a panel-shaped mold, the raw material liquid C and the raw material liquid were mixed at a weight ratio of 1:1 and poured in two pieces into the above-mentioned mold whose temperature was controlled to 85°C.

Gradually pressurize the raw material liquid in the mold so that a pressure of 10kr/- is applied to the raw material liquid 3 minutes after injection, then reduce the pressure, open the mold 4 minutes after injection, and harden. A molded rear panel was obtained.

(Performance of molded product) The obtained rear panel molded product had an excellent surface gloss of 95, and was a molded product with an excellent appearance without defects such as sink marks on the surface or internal voids.

The residual monomer in the molded product was as low as 1.5%, and even after immersion in ethanol for 91 hours, no cracking or sagging occurred, making the molded product suitable as an exterior decorative part for an automobile.

Example 3 (Preparation of Ring Syrup) 700 g of methyl methacrylate, 1200 g of phenyl methacrylate, 100 g of methyl acrylate and 0.2 g of azobisisobutyronitrile were mixed in a reaction vessel at 60 g.
Prepolymerization was carried out with stirring at °C, and when the viscosity rose slightly, the mixture was rapidly cooled to prepare a viscous solution, ie, a ring syrup.

The viscosity (25°C) was 30 poise.

(Preparation of raw material liquid E) For 900 g of ring syrup, 100 g of tetraethylene glycol dimethacrylate, 8 g of glycol dimercaptoacetate, 1 part of copper naphthenate (Cu content 10%)
Weight% methyl methacrylate t9t&1g was added and mixed uniformly to prepare raw f4 liquid E.

The viscosity (25°C) was 28 poise.

(Preparation of raw material liquid F) For 1000 g of ring syrup, add t-butylperoxy-
Add 15 g of 2-ethylhexanoate and 1 g of dimethyl laurylamine hydrochloride, mix and dissolve uniformly, and prepare raw material solution F.
was prepared.

The viscosity (25°C) was 30 poise.

(Cast molding) Using a mold having the shape of a concentrating solar collector, which is a dome-shaped point concentrating Fresnel lens with an average thickness of 5.7 mm and a diameter of 1450 mm and a surface curvature radius of 2000 mm, Raw material liquid E and raw material liquid F were mixed at a weight ratio of 1:1 and poured into the above-mentioned mold whose temperature was controlled to 85° C. for 30 seconds.

Gradually pressurize the raw material liquid in the mold, and 3 minutes after injection, 20
A pressure of kg/cd was applied to the raw material liquid, and then the pressure was reduced, and the mold was opened 5 minutes after the liquid was injected to obtain a cured light-concentrating solar collector molded article.

(Performance of molded product) The obtained concentrating solar collector has a total light transmittance of 9
The molded product had a transparency of 1.0% and had an excellent appearance with no defects such as sink marks on the surface or internal voids.

In addition, the residual monomer in the molded product is as low as 1.2%.
The molding shrinkage was highly accurate at 0.1%, and the molded product showed no internal distortion even when visually observed using a polarizing plate, making it suitable as a concentrating solar collector.

Example 4 (Preparation of ring syrup) 9 kir of methyl methacrylate, 8 kg of cyclohexyl methacrylate, 3-styrene and 40 g of azobisisobutyronitrile were prepolymerized in a reaction vessel with stirring at 70°C, and when the viscosity increased slightly. A viscous solution, a ring syrup, was prepared.

The viscosity (25°C) was 5 voids.

(Preparation of raw material liquid G) For 19 kg of ring syrup, 1 kg of tetraethylene glycol dimethacrylate, 200 g of t-butylperoxyacetate, and too much 2-mercaptopropionic acid.
g, 10 g of dimethyloctylamine hydrochloride, and 14 g of a 1% by weight metal methacrylate solution of naphthenic acid w4 (Cu content 10%) were added and uniformly mixed and dissolved to prepare raw material liquid G.

The viscosity (25°C) was 4 poise.

(Cast molding) Using a mold having a thickness of 10+ m and a shape of a 900 x 1800 crane-sized flat plate door material, the raw material liquid G was injected under pressure into the above-mentioned mold whose temperature was adjusted to 70° C. for 50 seconds.

Gradually pressurize the raw material liquid in the mold to 50k in 7 minutes after injection.
A pressure of g/cd was applied to the raw material liquid, and then the pressure was reduced, and 10 minutes after the liquid was injected, the mold was opened to obtain a cured door material molded product.

(Performance of molded product) The obtained molded door material has transparency with a total light transmittance of 93.0% and a haze value of 0.7%, and has an appearance with no defects such as voids inside sink marks on the surface. It was an excellent molded product.

In addition, the residual monomer in the molded product is as low as 1.5%.
The molding shrinkage was highly accurate at 0.1%, and the molded product showed no internal distortion even when observed with the naked eye using a polarizing plate. Furthermore, the molded product had warp of less than 1 crane, making it suitable as a material for a house. .

Claims (2)

[Claims] (1) A method for producing a large-sized resin molded article, which comprises injecting a raw material liquid mainly consisting of a vinyl monomer containing or not containing a polymer into a mold, and polymerizing and curing it under heating and pressure. (2) The large resin molded body is an automobile glazing part,
The manufacturing method according to claim (1), which is an automobile exterior decorative part or a house fixture/decoration item.