KR19990001317A - Thermosetting acrylic resin composition and method for producing molded article using same - Google Patents

Abstract

It is an object of the present invention to provide a thermosetting acrylic resin composition which is easy to mold and has excellent productivity, beautiful appearance and excellent mechanical properties, and a method for producing a molded article having a desired shape by compression molding using the same.

Acrylic resin composition of the present invention

A. 100 parts by weight of an acrylic syrup having a viscosity of 3000 cps (centipoise) to 2 million cps

B. 0.1 to 50 parts by weight of polyfunctional unsaturated compound

C. 50 to 600 parts by weight of inorganic filler

D. 0 to 300 parts by weight of reinforcement

E. 0.005 to 5 parts by weight of radical reaction initiator

F. 0 to 300 parts by weight of artificial stone crushed particles to express the texture of natural stone

G. 0.1-10 parts by weight of low storage agent

H. 0.1 to 10 parts by weight of other additives such as polymerization regulators, heat and light stabilizers, pigments, etc. The molded article of the present invention places the acrylic resin in the center of the press mold subjected to the release treatment, and the mold temperature is 50-150 ℃, It is produced by compression molding under conditions of a molding pressure of 30-200 kg / cm 2 and a molding time of 2 minutes to 20 minutes.

Description

Thermosetting acrylic resin composition and method for producing molded article using same

The present invention relates to a thermosetting acrylic resin composition and a method of manufacturing a molded article using the same, and more particularly, to an acrylic bulk molding compound (Bulk Molding Compound, hereinafter BMC), which is easy to mold, has excellent productivity, and has excellent appearance and mechanical properties. And a method for producing an artificial marble molded article using the same.

Recently, high-quality artificial marble, which is widely used as building interior materials, is classified into two types, acrylic and unsaturated polyester, depending on the base resin used. Among them, acrylic is transparent and luxurious due to the characteristics of the resin itself. Due to its texture, balanced mechanical properties and excellent weather resistance, the demand continues to increase in many applications. For example, the tops of various counter tops such as sink tops, vanity tops, reception desks of banks and securities stores, interior wall materials of merchandise stores, partitions, bathtubs, sink bowls, washbasins and interior sculptures. It is widely used around the world.

Most of these acrylic artificial marbles are manufactured by the casting process, and thus, when the molded product is manufactured in a complicated process or becomes thinner, the production time is reduced due to a complicated process and a longer manufacturing time. It has the disadvantage of being difficult or limited. (European Patent 006951, European Patent 0516299 A1, Japanese Unexamined Patent Publication No. 7-033498, Japanese Unexamined Patent Publication No. 4-110112, European Patent 0285046)

Unlike unsaturated polyester resins, acrylic resins have a very high polymerization shrinkage during molding, and defects due to shrinkage such as think marks tend to appear on the appearance of the final molded product, and it is difficult to release and demold when forming at high temperatures to increase productivity. There are disadvantages. In addition, it is necessary to appropriately adjust the particle size and amount of the inorganic filler in the BMC in order to obtain transparency, which is a characteristic of the acrylic artificial marble. However, even in such a case, unlike the unsaturated polyester resin, it is difficult to thicken and thus, the adhesiveness of the composition has a disadvantage in that handleability is deteriorated. Due to these problems, there is an additional disadvantage that it is difficult to use a mold for molding a large number of unsaturated polyester resins BMC, SMC (Sheet Molding Compund), which is economically significant because of the high cost of mold manufacturing. .

Acrylic BMC composition in Japanese Patent Application Laid-Open No. 4-081448 When a mold for molding unsaturated polyester resin BMC is used without using a mold having a unique structure as in Japanese Patent Laid-Open Publication No. 7-195396, shrinkage after compression molding There arises a problem of appearance defects. In the mold structure such as Japanese Patent Application Laid-Open No. 7-195396, when rubber having a certain hardness is used as a sealing material, shrinkage or bubbles can be removed, but as the number of moldings increases, heat and pressure are repeatedly applied, which causes deformation and aging. Therefore, in order to obtain a uniform shape product during mass production, there is a disadvantage that the sealing material must be replaced regularly. In addition, since the mold structure is fundamentally different from the molding molds of general unsaturated polyester resins BMC and SMC, there is a disadvantage in that a mold must be manufactured in order to manufacture a separate molded product. In Japanese Patent Laid-Open No. 61-171713 and Japanese Patent Laid-Open No. Hei 5-124844, compression molding is possible only after thickening by a separate polymerization process, which results in a longer production process than general BMC which can be molded immediately after kneading. have.

Due to the problems of the prior art as described above, it is very rare to commercialize a molded article manufactured using the press industry with an acrylic BMC, and so far it has not been commercialized.

The present invention is to solve the problems of the prior art, and provides a thermosetting acrylic resin composition which is easy to mold, excellent in productivity, beautiful in appearance, and excellent in mechanical properties, and a method for producing a molded article having a desired shape by compression molding using the same. For that purpose.

1 (A): cross-sectional view of a molded article molded in Example 7-12 of the present invention

(B): Plan view of the molded article molded in Example 7-12 of the present invention

Acrylic resin composition of the present invention

A. 100 parts by weight of an acrylic syrup having a viscosity of 3000 cps (centipoise) to 2 million cps

B. 0.1 to 50 parts by weight of polyfunctional unsaturated compound

C. 50 to 600 parts by weight of inorganic filler

D. 0 to 300 parts by weight of reinforcement

E. 0.005 to 5 parts by weight of radical reaction initiator

F. 0 to 300 parts by weight of artificial stone crushed particles to express the texture of natural stone

G. 0.1-10 parts by weight of low storage agent

H. It is composed of 0.1 to 10 parts by weight of polymerization additives, heat and light stabilizers, pigments and other additives, and this is placed in the center of the heated metal mirror mold and press-molded to produce an artificial marble molded article of a desired shape.

Hereinafter, the present invention will be described in detail.

First, the components constituting the composition of the present invention will be described.

A. Acrylic syrup with a viscosity of 3000 cps to 2 million cps

Acrylic syrup in this invention consists of a fixed amount of the 1 type (s) or 2 or more types of monomers which have a structure of following formula (I), and the polymer of the same or bicomponent monomer melt | dissolved in it.

Monomer CH ₂ = CR ¹ R ² , Polymer-(CH ₂ CR ¹ R ² ) _n- (I)

Where R ¹ : H, CH ₃

R ² : CO ₂ R ³ , CONHR ⁴

R ³ : H, alkyl group (C ₁ -C ₁₅ ), alcohol group (C ₁ -C ₁₀ )

R ⁴ : H, alkyl group (C ₁ -C ₁₅ ), alcohol group (C ₁ -C ₁₀ )

n = 500-1500

In the case of the monomer, a composition having a structure satisfying the above formula may be used alone or in combination of two or more, without particular limitation, and the amount of use is determined according to the molecular weight and content of the polymer. That is, the acryl syrup may be prepared by partial polymerization of monomers, or may be prepared by dissolving the polymer in the monomers, and it is also possible to mix the two methods. Whichever method is used, the viscosity of the final syrup should satisfy the range of 3000 cps to 2 million cps at room temperature (23 ° C.). The viscosity of the syrup can be adjusted according to the type and content of the composition, but adjustment within the viscosity range is preferred, and the exact viscosity is the viscosity of the point that satisfies the target quality in the state in which the adjustment other than the system is selected. Final selection is preferred. When the viscosity of the syrup is less than 3000 cps, the manufacturing and handling properties of the BMC are poor, the fluidity of the BMC is insufficient in the mold, the polymerization time is long, and the shrinkage phenomenon in the molded product after polymerization is not good. In addition, when the viscosity of the syrup exceeds 2 million cps, the viscosity is too high, making it difficult to uniformly mix the composition and shorten the shelf life of the BMC is difficult to store. Therefore, the viscosity of the syrup used in the present invention is 3000cps-2 millioncps, preferably 30,000cps-1,50millioncps, more preferably 100,000cps-1 millioncps. Viscosity is measured using a Brookfield Viscometer HB Type.

B. Multifunctional Unsaturated Compounds

In the present invention, it is preferable to add a polyfunctional unsaturated compound containing two or more double bonds copolymerizable with unsaturated monomers of acrylic syrup in the molecule in order to improve chemical resistance, fouling resistance, heat resistance and mechanical properties of the final molded product. Such compounds include trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,4-butanethiol diacrylate, epoxidized bisphenol A dimethacrylate, Any compound that satisfies the above conditions, such as epoxidized bisphenol A diacrylate and pentaerythritol triacrylate, may be used without particular limitation. If the content is less than 0.1 part by weight based on 100 parts by weight of the acrylic syrup, it is difficult to obtain the above-mentioned effects. If the content exceeds 50 parts by weight, cracks are easily generated or broken due to excessive crosslinking and shrinkage effects, and there are disadvantages in economic disadvantages. .

Therefore, the content of the polyfunctional unsaturated compound in the present invention is 0.1-50 parts by weight, preferably 0.5-30 parts by weight, more preferably 1.0-20 parts by weight based on 100 parts by weight of the acrylic syrup.

C. Inorganic Filler

Inorganic fillers used in the present invention are generally selected from inorganic powders commonly used in the art. Suitable inorganic fillers include hydrates of metal oxides such as silica, titanium dioxide, alumina, aluminum silicate, magnesium silicate, calcium carbonate, talc, clay, aluminum hydroxide, magnesium hydroxide and calcium hydroxide. Hydrates of double metal oxides, in particular aluminum hydroxide, are preferred in that the resulting resin composition can be readily produced into a flame retardant cured product having a transparent and beautifully marbled appearance. However, the mechanical properties are inferior as compared with products obtained using fillers such as aluminum silicate and silica. Therefore, the inorganic filler is preferably used alone or in combination of two or more according to the required physical properties and appearance of the final product. In the present invention, hydrates of metal oxides such as aluminum hydroxide, particularly aluminum hydroxide, are mainly used.

As the inorganic filler, an average particle size of 0.1-200 microns, preferably 5-50 microns, is used. In order to exhibit the characteristic transparency of artificial marble, a filler having a particle size of 1 micron or less is preferably used. If the amount of the inorganic filler used is less than 50 parts by weight with respect to 100 parts by weight of the acrylic syrup, the physical properties such as heat resistance of the final molded product is insufficient and a good marble-like feeling cannot be obtained. On the contrary, when it exceeds 600 parts by weight, the resin composition lacks fluidity, transparency is lowered, and mechanical strength is inferior. Therefore, the content of the inorganic filler in the present invention is 50-600 parts by weight, preferably 100-400 parts by weight, more preferably 150-350 parts by weight.

D. Stiffener

The present invention is particularly useful for producing a molded article having a beautiful appearance with a thickness of less than 6 mm, which is difficult to be molded by the existing casting method. Therefore, when the improvement of mechanical strength is required according to the type of molded article, as well as the inorganic reinforcing material such as glass fiber (glass fiber) as in the BMC using unsaturated polyester resin, it is possible to achieve the object by using various organic reinforcing materials described below. Can be.

Organic reinforcing materials include the following. Natural products include wood flour, shell fibers, cotton fibers, vegetable fibers, etc., and synthetic compounds include manufactured cellulose (regenerated cellulose), acrylonitrile fibers (polyacrylonitrile fibers), Alicyclic polyamide fibers (polyamides, aliphatic (nylon) fibers), aromatic polyamide fibers (polyamide, aromatic (aramid) fibers), polyester fibers (polyesterfibers), polytetrafluoroethylene (teflon) fibers, polyvinyl alcohol powder Or polyvinyl alcohol fibers or fibers, rubber dust (hard), vulcanized rubber (rubber dust, vulcanized).

The size of the reinforcement (average particle size, denier, short fiber length, etc.) can be appropriately selected according to the type of reinforcement and the end use of the molded article, or can be used alone or in combination of two or more. When the amount exceeds 300 parts by weight with respect to 100 parts by weight of the acrylic syrup, as well as the disadvantages of excessive input of an inorganic filler, excessive kneading heat may be generated when kneading using a kneader, which may cause hardening of the BMC before molding. There is a problem in that it is difficult to uniformly disperse the remaining composition except for the reproducible final product. Therefore, the content of the reinforcing material in the present invention is 0-300 parts by weight, preferably 0-150 parts by weight, more preferably 0-100 parts by weight with respect to 100 parts by weight of the acrylic syrup.

E. Radical Initiator

In order to polymerize the unsaturated monomer and the polyfunctional unsaturated compound in the composition of the present invention, various methods may be used, but the organic peroxide is used as a radical reaction initiator, and the hot plate attached to the press is used as a heat source to pressurize and polymerize in a mold. The method is the most efficient. However, it is clear to those skilled in the art that the present invention is not limited to this polymerization method alone. The organic peroxide used in the present invention is not particularly limited as long as it can decompose within the molding temperature to initiate a radical reaction, but from an economic point of view, the molding time is as high as 20 to obtain a high polymerization rate in a short time. It is preferable to make it into minutes or less. When the molding time exceeds 20 minutes, the time shortening degree is less than the molding time by the casting method, thereby reducing the effect of the present invention. From this point of view, the reaction start time is accelerated by using one organic peroxide having a 1-hour half-winding temperature of 40-75 ° C., and a high temperature is obtained by using an organic peroxide having a 1-hour half-life temperature of 75-130 ° C. It is particularly advantageous to complete the reaction at, but of course it is also possible to use one type of organic peroxide alone or three or more types having a half-life temperature of 30-130 ° C. depending on the molding conditions.

If the 1 hour half-life temperature of the peroxide used is less than 40 ° C, curing may occur due to kneading heat when kneading the composition in a kneader, as well as shortening the pot life of the BMC. In order to prevent this, when the polymerization inhibitor is added, it may not affect the polymerization reaction. In addition, when the one-hour half-life temperature of the used peroxide exceeds 130 ° C, sufficient amount is not decomposed at the molding temperature and time, so that it is difficult to obtain a desired polymer, or it may remain in the cured product and degrade weather resistance such as discoloration. have.

The addition amount is preferably selected based on the content of the active oxygen content according to the molecular weight difference, purity, etc. of the organic peroxide and the decomposition of the organic peroxide under molding conditions (temperature, time, composition of BMCN, etc.). The organic peroxide content is 0.005-5 parts by weight, preferably 0.01-3 parts by weight, more preferably 0.05-2 parts by weight with respect to 100 parts by weight of the acrylic syrup. When the amount of peroxide is less than 0.005, the polymerization curing reaction may be too slow. When the amount of the peroxide is over 5 parts by weight, the polymerization reaction may be too large, making it difficult to control the molding operation. It is easy to occur and has a disadvantage in that the pot life is shortened due to kneading of kneader.

Organic peroxides having a one-hour half-life temperature of 40-75 ° C. include isobutyl peroxide, 2, 4-dichlorobenzoyl peroxide, 2, 4, 4-trimethyl pentyl peroxy neodecanate, t-butylperoxy pival Latex, t-butylperoxy neodecanate, di-3-methoxy butyl peroxy dicarbonate, bis (4-t-butylcyclohexyl) peroxy dicarbonate, and 1 hour half-life temperature of 75-130 ° C. Organic peroxides having diethylene glycol bis (t-butyl peroxycarbonate), t-butyl peroxy isopropyl carbonate, t-butyl peroxybenzoate, t-amyl peroxy 2-ethyl hexanoate, 1 , 1-di-t-butyl peroxy 3, 3, 5-trimethyl cyclohexane, benzoyl peroxide, lauroyl peroxide, and the like, but not limited to one hour half-life temperature is a peroxide in the above temperature range Can be used appropriately according to all applications .

F. Artificial stone crushed particles to express the texture of natural stone

The method for producing the particles made by crushing the artificial stone is as follows. 0-250 parts by weight of fillers such as calcium carbonate, aluminum hydroxide, magnesium hydroxide, aluminum silicate, silica, clay, and 100 parts by weight of partially polymerizable polymerizable resin such as unsaturated polyester resin, acrylic resin, phenol resin, epoxy resin, etc. 0-2 parts by weight of inorganic pigments such as titanium dioxide, carbon black, iron oxide, and other organic pigments for color expression of particles are added and polymerized. The bulk polymer prepared as described above is crushed using an impact crusher, a pulverizer, etc., and then washed using a dehydrator to obtain particles having a desired particle size. Particle washing is to obtain uniform color when manufacturing moldings by removing fine powder on the surface of particles used.As a solvent, which has a low boiling point such as acetone, styrene monomer and methyl ethyl ketone, and is volatile, it is easy to remove Use to facilitate removal from particles after washing. When obtaining the bulk polymer, a conventional method generally applied to each resin is used. As the curing agent and the polymerization accelerator, for example, peroxides such as benzoyl peroxide, AIBN, lauryl peroxide, etc. are added to radical polymers such as acrylic resins and unsaturated polyester resins. In the case of epoxy resins, tertiary amines, acid anhydrides, and imides are used. Sols are used as curing agents, and in the case of phenol resins, urea and melamine may be used for crosslinking. The content of the particles in the present invention is 0 to 300 parts by weight based on 100 parts by weight of the acrylic syrup.

G. Low Festival

The polymerization shrinkage rate of the unsaturated polyester resin is about 7%, but the acrylic resin is about 21%, about three times the unsaturated polyester resin. Due to this molding shrinkage, various studies have been conducted to lower the relative content of acrylic unsaturated monomer in the composition of acrylic BMC. For example, increasing the content of inorganic fillers or increasing the content of polymers in the syrup has been studied, but the transparency and handling properties of acrylic artificial marble are lowered, and the BMC and unsaturated polyester resins If the liver is difficult to obtain smoothness. Although the resin composition containing the low shrinkage agent provided in the present invention alone does not sufficiently exhibit a low shrinkage effect, it is possible to obtain a molded article having an appearance in which shrinkage problems are eliminated when applied to the above-described mold structure and molding method. It is most effective to use cellulose acetate butyrate (hereinafter referred to as CAB) as the low shrinkage agent used in the present invention.

In the present invention, it is effective that CAB has a ratio of 20-50% butyl group, 10-20% acetyl group, and 0.5-2.5% receiver based on mole% of butyl group, acetyl group, and hydroxyl group in the polymer. Such a CAB can be obtained by esterifying a mixture of purified linta, glacial acetic acid, lactic acid, anhydrous lactic acid and the like with sulfuric acid as a catalyst, and it is also possible to purchase and use a commercialized product.

When the CAB content, which is a low shrinkage agent, is less than 0.1 part by weight based on 100 parts by weight of the acrylic syrup, the additive effect is not sufficient, and when the content exceeds 10 parts by weight, transparency of the molded article is deteriorated.

Other additives such as polymerization regulators, heat and light stabilizers, pigments, dyes, thickeners, surfactants, internal mold release agents, etc. may be appropriately selected in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic syrup.

The method of manufacturing a molded article using the said thermosetting resin composition (acryl BMC) is demonstrated below.

Three types of molds are basically used for compression molding, such as flash mold, positive mold, and semi-positive mold. Any of three types of molds can be applied in the present invention. In addition, the shape of the mold can be applied to both simple two-dimensional cases such as plywood and complex three-dimensional shapes such as bathtubs.

In the present invention, the plywood shape and the bathtub shape are mainly described, but the present invention is not limited thereto and is applicable to all methods applicable through the concept of the present invention such as insert molding.

First, one of the upper or lower molds of an existing press die is released to one of the unused surfaces of both sides of the molded product, for example, the outer surface of the bathtub. The purpose of the release treatment is twofold. First, the press surface faithfully reflects the mold surface on the use side of the molded part, and the non-use side compensates for the pressure applied to the resin composition in the mold to compensate for the shrinkage caused by the rapid polymerization of the monomer to shrink the entire molded part. It is to obtain a final molded product without deterioration of appearance. The second is to make the release easier. Even if the release treatment of the present invention or a separate release agent is not used, the releasability is excellent when demolding the resin composition described above. This difficulty is alleviated.

There are a number of release treatment methods, but the method used in the present invention is a method capable of forming about 500 or more times in one treatment under ordinary molding compression conditions. First, there is a method of using a release film or sheet. The release film or sheet studied in the present invention includes polyvinyl alcohol resins, fluorocarbon resins, polyethylene terephthalate resins, silicone resins, polyolefin resins such as polyethylene or polypropylene, or release treated papers treated with such resins. Adhesive or non-adhesive films made of organic or inorganic fibers such as glass fiber, polyester, nylon and polyvinyl alcohol as reinforcement materials or various materials on sheets can be used. Anything that is not available is available by choice. As a second method, there is a method of coating the resin material on a non-use surface. It is also possible to mix the two methods.

In using the release materials, of course, a material having heat resistance and strength sufficient to withstand the applied molding temperature and pressure should be selected. The thickness of the film, sheet or coating resin may be appropriately selected and used within the range of 500 microns or less, which satisfies the above two purposes. When the thickness exceeds 500 microns, the molding time may be lengthened by delaying the heat transfer of the mold, and the thickness of the final molded product may be excessively reduced compared to before the treatment.

In the present invention, when the silicone resin is used, the shrinkage correction and the release effect are shown to be the largest, but are not necessarily limited to the silicone resin.

The mold temperature in the compression molding conditions of the present invention is particularly effective in the Tg ± 30 ℃ range of the final product. The Tg (glass transition temperature) of the final product varies depending on the type of resin used in the composition and the degree of crosslinking, but has a range of approximately 80-120 ° C., so the mold temperature is 50-150 ° C., preferably 60-140 ° C. More preferably 70-130 ° C. If the mold temperature is less than 50 ℃ has a disadvantage that the molding time is too long, if it exceeds 150 ℃ there is a disadvantage that the mold must be demolded by cooling the mold.

The molding pressure is appropriately 30-200 kg / cm 2. If the molding pressure is less than 30㎏ / ㎠ and the mechanical properties may be reduced, if the molding pressure exceeds 200㎏ / ㎠ it is not good for hydraulic equipment because the pressure is only high without improving the physical properties. Molding time is determined depending on the molding temperature and the type and content of the radical reaction initiator, but the range of 2 minutes to 20 minutes is appropriate. If less than 2 minutes, the pre-mixing (charge) to the mold (charge) to close the mold completely during the working time can not be locally hardened, this problem is more likely to occur when molding a large molded article. If the molding time exceeds 20 minutes, the economy is not good. Preferably it has a molding time of 3-12 minutes, more preferably 4-8 minutes.

Hereinafter, the present invention will be described in more detail in Examples and Comparative Examples, but they are not intended to limit the present invention.

Preparation Example: Preparation of Particles Textured in Natural Stone

100 parts by weight of an acrylic syrup (25 ° C., 20 poises), trimethyl, 20 parts by weight of propane trimethacrylate, 300 parts by weight of aluminum hydroxide, 0.1 to 1 parts by weight of a pigment expressing each color, and 0.05 parts by weight of benzoyl peroxide After the polymerization was carried out to form artificial stone, and then crushed and classified to prepare particles by particle size and color. Titanium dioxide, carbon black, iron oxide, cobalt blue, cadmium red, and the like were used alone or in combination as pigments expressing each color.

The shape, color and specification of the prepared particles are shown in Table 1 below.

TABLE 1

Example 1-6

40 parts by weight of an average molecular weight of 120,000 polymethyl methacrylate was completely dissolved in 60 parts by weight of industrial methyl methacrylate to obtain 100 parts by weight of an acrylic syrup having a viscosity of 120,000 cps, and trimethyl was 5 parts by weight of propane trimethacrylate and 0.1 stearic acid. Parts by weight, 0.5 part by weight of surfactant, 0.001 part by weight of polymerization regulator, 0.7 part by weight of 2,4-dichlorobenzoyl peroxide, 2 parts by weight of t-butylperoxybenzoate, 0.01 part by weight of ultraviolet absorber, 5 mm short glass fiber 10 Cellulose acetate butyrate (EAB-551-0.08 manufactured by Eastman Chemical Product Inc,) was added as the weight part and the low shrinkage agent as shown in Table 2 below. Here, 200 parts by weight of aluminum hydroxide having an average particle diameter of 20 microns and 50 parts by weight of MCI prepared in the above preparation and 100 parts by weight of MC7 were kneaded in a kneader as particles for expressing the texture of natural stone to obtain a uniformly mixed acrylic BMC. The kneading method followed the usual method at the time of BMC kneading. A glass fiber-reinforced silicone resin sheet having a thickness of 0.23 mm was cut into 59.5 cm on one side of a square flat plate mold having a length of 60 cm on one side and a depth of 3 mm. The acrylic BMC prepared above was placed and heated and pressed for 10 minutes under conditions of a mold temperature of 100 ° C. and a molding pressure of 70 kg / cm 2 to obtain a flat artificial marble having a thickness of 3 mm and a length of 60 cm. The charge rate of BMC was 15% of the molded plate. The molding results are shown in Table 3.

TABLE 2

Content of cellulose acetate butyrate

Example 7-12

Molded under the same composition and conditions as in Example 1-6, but a molded article having a diameter of 30cm of the outermost circle having a thickness of 3mm having a cross section as shown in FIG. The mold which the silicone resin coating process of the shaping | molding surface of the metal mold | die corresponding to the back surface of each molded article to the thickness of 60 microns was used, respectively. The molding results are shown in Table 3.

[Comparative Example 1-4]

Molds were molded as in Examples 1, 4, 7, and 10, but were not subjected to silicone release, and the molding results are shown in Table 3.

[Comparative Example 5-8]

Molding was carried out as in Examples 1, 4, 7, 10, but the mold was used to mold the silicon on both sides of the mold, the molding results are shown in Table 3.

TABLE 3

Molding result

1) Preferred order of molding condition: ◎ ○ △ ×

2) The Rockwell hardness of the mechanical properties is measured at the site of use.

The thermosetting acrylic resin according to the present invention is easy to mold, excellent in productivity, beautiful in appearance and excellent in mechanical properties, and the compression molding method of the present invention has no defects in the appearance of the molded article and facilitates mold release.

Claims (7)

Thermosetting acrylic resin composition, characterized in that consisting of the following composition. A. 100 parts by weight of an acrylic syrup having a viscosity of 3000 cps (centipoise) to 2 million cps B. 0.1 to 50 parts by weight of polyfunctional unsaturated compound C. 50 to 600 parts by weight of inorganic filler D. 0 to 300 parts by weight of reinforcement E. 0.005 to 5 parts by weight of radical reaction initiator F. 0 to 300 parts by weight of artificial stone crushed particles to express the texture of natural stone G. 0.1-10 parts by weight of low storage agent H. 0.1 to 10 parts by weight of other additives such as polymerization regulators, heat and light stabilizers, pigments The thermosetting acrylic resin composition according to claim 1, wherein the acrylic syrup is composed of a polymer of one or two or more monomers having the structure of the following formula (I) and a polymer of the same or two-component monomers dissolved therein. Monomer CH ₂ = CR ¹ R ² , Polymer-(CH ₂ CR ¹ R ² ) _n- (I) Where R ¹ : H, CH ₃ R ² : CO ₂ R ³ , CONHR ⁴ R ³ : H, alkyl group (C ₁ -C ₁₅ ), alcohol group (C ₁ -C ₁₀ ) R ⁴ : H, alkyl group (C ₁ -C ₁₅ ), alcohol group (C ₁ -C ₁₀ ) n = 500-1500 According to claim 1, The radical reaction initiator is characterized in that one organic peroxide having a one-hour half-life temperature of 40-75 ℃ and one organic peroxide having a one-hour half-life temperature of 75-130 ℃ Thermosetting acrylic resin composition. The method of claim 1, wherein the low shrinkage agent is based on the mole% of the butyl group, acetyl group, hydroxyl group in the polymer 20% to 20% butyl group, 10-20% acetyl group, 0.5-2.5% hydroxyl group A cellulose acetate butyrate having a thermosetting acrylic resin composition characterized by using. An acrylic resin made of the composition of claim 1 is placed in the center of the press mold subjected to the release treatment on one of the unused surfaces of the molded product from the upper mold or the lower mold of the mold, and the mold temperature is 50-150 ° C., A method for producing a molded article, characterized in that the molded product with a molding pressure of 30-200kg / ㎠, molding time 2 minutes-20 minutes by compression molding to produce a molded article of thickness 6mm or less. The method for producing a molded article according to claim 5, wherein the release treatment is performed using a release film, sheet, or coating resin having a thickness of 500 microns or less. The release film, the sheet, the coating resin is a polyvinyl alcohol resin, a fluorine resin, a polyethylene terephthalate resin, a silicone resin, a polyolefin resin such as polyethylene or polypropylene, the paper release-treated with such resin, A method for producing a molded article characterized in that the adhesive or non-adhesive film or sheet prepared by using organic or inorganic fibers such as glass fiber, polyester, nylon, polyvinyl alcohol as a reinforcing material in the resin.