JP2005081603A - Molding method of transparent acrylic resin product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method of a transparent acrylic resin product for obtaining a molded product having high mechanical strength, transparency and gloss and excellent in weatherability and boiling resistance. <P>SOLUTION: A mixture, which is obtained by compounding 50-300 pts.wt. of an acrylic resin powder (B) and 0.1-5.0 pts.wt. of a polymerization initiator (E) with 100 pts.wt. of an acrylic resin syrup (A), which is composed of 100-20 wt.% of a (meth)acrylic monomer (A1) consisting mainly of methyl (meth)acrylate and 0-80 wt.% of a (meth)acrylic polymer (A2), is aged under a temperature condition of 10-60°C to obtain an acrylic resin molding material (D1). The acrylic resin molding material (D1) and an acrylic resin molding material (D2) obtained by compounding 1-50 pts.wt. of a crosslinking monomer (C) with the mixture comprising the components (A), (B) and (C) are together used in a weight ratio: the material (D1): the material (D2)=60:40-20:80 and the material (D1) and the material (D2) are superposed one upon another to be heated, pressed and molded at a mold temperature of 110-140°C under a pressure of 1-10 MPa. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for molding a transparent acrylic resin product. More specifically, the present invention relates to a method for molding a transparent acrylic resin product that has high mechanical strength, transparency, and gloss, is transparent and has a high-class feeling, and is useful as an artificial marble product that is not deformed or warped.

(Meth) acrylic artificial marble blended with (meth) acrylic resin and inorganic filler is excellent in appearance of molded products, weather resistance, etc., and as a material compatible with styrene-free in living space, bathtub, wash bowl, kitchen Used for counters.
However, since the refractive index of the (meth) acrylic resin is different from that of inorganic fillers such as aluminum hydroxide, there is a disadvantage that the molded product is white and turbid and loses transparency. In particular, when a decorating material is blended, the three-dimensional effect of the pattern is lost and a high-quality decoration effect cannot be obtained.

Various studies have been made to solve the above problems. For example, Patent Document 1, Patent Document 2, and Patent Document 3 include a technique related to a resin composition for injection molding in which silica powder having a refractive index close to that of an acrylic resin is blended to impart transparency to an acrylic artificial marble. Although it has been reported, it is still impossible to obtain a completely transparent molded body.
In addition, the acrylic resin material has a large thermal shrinkage, and the amount of deformation greatly depends on the temperature of the mold, so that the acrylic resin material is greatly deformed after demolding and warpage is likely to occur.

  Patent Document 4 and Patent Document 5 provide a molded product with a deep and high-class feeling due to the transparent layer of the acrylic resin by using a technique in which the back surface of the acrylic sheet manufactured by vacuum forming is reinforced with an FRP layer. It has been shown that However, there are problems in that the shape of the acrylic sheet has few degrees of freedom and it is difficult to deal with a small variety of products, and the manufacturing process is complicated, leading to an increase in product cost. Furthermore, when the FRP layer is disposed on the back surface of the acrylic sheet, there is a slight difficulty in adhesion between the acrylic sheet and the FRP material. As shown in Patent Document 6, the adhesion between the acrylic sheet and the FRP material is achieved by containing a compound comprising a (meth) acrylic polymer containing methacrylic acid and / or acrylic acid as essential components and an aluminum chelate. Although there is a method of improving the property, the adhesion is not sufficient, and it may be peeled off by a falling ball impact test or the like.

  On the other hand, Patent Document 7 proposes a technique for producing a high viscosity acrylic syrup in which an acrylic monomer and an acrylic polymer are mixed at 50 ° C. or higher using a twin-screw kneader. There is a problem that special equipment is required to handle the viscous material and the energy cost is high.

  Accordingly, there is a demand for an artificial marble product that can be easily molded by a general-purpose press molding apparatus that is generally used, has a transparent feeling and a high-class feeling, and has no deformation or warping.

Japanese Patent Laid-Open No. 03-285854 Japanese Patent Laid-Open No. 04-275314 Japanese Patent Laid-Open No. 09-110498 JP-A-08-134161 Japanese Patent Application Laid-Open No. 08-332680 JP 07-247328 A JP-A-10-158332

  The present invention has been made in view of the above circumstances, and has high mechanical strength, transparency, and gloss, and further has a transparency and a high-class feeling with little deformation and warping after taking out from the mold. It is providing the molding method of a resin product.

  As a result of earnest research on the above problems, the present inventors have found that the above problems can be solved by forming using two types of acrylic resin molding materials having different thermal expansion coefficients made of molding materials of a specific composition. .

That is, the present invention
(1) Acrylic syrup (A) comprising 100 to 20% by weight of (meth) acrylic monomer (A1) mainly composed of methyl methacrylate and 0 to 80% by weight of (meth) acrylic polymer (A2) Acrylic obtained by aging a mixture of 50 to 300 parts by weight of acrylic powder (B) and 0.1 to 10 parts by weight of polymerization initiator (C) in 100 parts by weight under a temperature condition of 10 to 60 ° C. Acrylic resin molding material (10) by kneading 10 to 50% by weight of a crosslinking monomer (E) in a mixture of the resin molding material (D1) and the above (A), (B) and (C) D2) is used in the range of acrylic resin molding material (D1): acrylic resin molding material (D2) = 60: 40 to 20:80 (weight ratio), mold temperature 110 to 140 ° C., pressure 1 to 10 MPa. Acrylics characterized by being molded with Molding method of the system resin product.

(2) The acrylic resin molding material (D2) is molded, and the acrylic resin molding material (D1) is disposed between the obtained molded product and the low-temperature side mold and molded. A method for molding an acrylic resin product according to 1).

(3) The acrylic resin molding material (D1) is molded, and the acrylic resin molding material (D2) is disposed between the obtained molded product and the high temperature side mold and molded ( A method for molding an acrylic resin product according to 1).

(4) Molding of acrylic resin product according to any one of (1) to (3) above, wherein 1 to 200 parts by weight of pattern material (F) having a particle size of 0.05 to 100 μm is further mixed. Method.

(5) The method for molding an acrylic resin product according to any one of the above (1) to (4), wherein 1 to 100 parts by weight of a fiber reinforcing material (G) having a length of 1 to 50 mm is further mixed. .
Is a summary.

  According to the method of the present invention, even in an acrylic resin molding material having a larger coefficient of thermal expansion than an unsaturated polyester resin or vinyl ester resin, it has high mechanical strength, transparency and gloss, An acrylic resin product useful as an artificial marble having a transparent feeling and a high-class feeling with little deformation and warping after being taken out of the container can be obtained.

  The present invention relates to an acrylic resin molding material mainly composed of methyl methacrylate and a polymer thereof, and two types of acrylic resin molding materials (D1) and (D2) having different thermal expansion coefficients depending on the presence or absence of a crosslinking monomer. ) (Coefficient of thermal expansion: (D1)> (D2)), one of the acrylic resin molding materials (D1) or (D2) is first molded, and then the other acrylic resin is molded. This is a two-stage molding method for molding a resin-based molding material. According to the method of the present invention, molding is performed under conditions of a mold temperature of 110 to 140 ° C. and a pressure of 1 to 10 MPa even in an acrylic resin molding material having a higher coefficient of thermal expansion than an unsaturated polyester resin or vinyl ester resin. The deformation and warpage of the molded product after being performed can be kept small.

  In the present invention, the two kinds of acrylic resin molding materials are used in a weight ratio of acrylic resin molding material (D1): acrylic resin molding material (D2) = 60: 40 to 20:80, preferably Is used at 40:60 to 30:70. When the usage ratio of the acrylic resin molding material (D1) is larger than the above range, the amount of deformation and warpage after the molded product after molding is taken out from the molding die is large. Conversely, when the usage ratio of the acrylic resin molding material (D2) is larger than the above range, the acrylic resin molding material (D1) and (D Due to the difference in thermal expansion coefficient from D2), a large stress is generated at the interface between the acrylic resin molding materials (D1) and (D2), and the adhesion may be weakened.

  In the method of the present invention, one method is that the above-mentioned acrylic resin molding material (D2) is molded first, and the other acrylic resin molding material (D1) is formed between the obtained molded product and the low temperature side mold. The other method is to mold the above acrylic resin molding material (D1) first, and then mold the other acrylic resin between the resulting molded product and the high temperature side mold. This is a method of arranging and molding the material (D2).

  The (meth) acrylic monomer (A1) constituting the acrylic resin molding materials (D1) and (D2) in the present invention is, for example, methyl methacrylate, methacrylic acid, acrylic acid, benzyl (meth) acrylate, n -Butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (Meth) acrylate, hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate , Dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acrylic (meth) acrylate, 2-hydroxyethyl (meth) acrylate 2- (meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxyethyl maleate, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate , Pentamethylpiperidyl (meth) acrylate, tetramethylpiperidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and the like, but are not limited thereto. These may be used by appropriately mixing two or more kinds.

  The usage-amount of the said acrylic monomer is the range of 20-100 weight% in acrylic syrup (A), Preferably it is 30-90 weight%. If it is less than 20% by weight, the resin viscosity becomes too high and the workability may be deteriorated.

  As the (meth) acrylic polymer (A2) constituting the acrylic resin molding materials (D1) and (D2) in the present invention, those obtained by appropriately polymerizing the (meth) acrylic monomer (A1) can be used. . As the polymerization method, known methods such as suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization and the like can be used. Those having a weight average molecular weight in the range of 10,000 to 600,000 have good mechanical properties and moldability, and more preferably in the range of 30,000 to 250,000. When the weight average molecular weight is less than 10,000, the mechanical properties of the obtained molded product are lowered, and when it exceeds 600,000, the viscosity of the methyl methacrylate-containing resin becomes too high, and the workability is lowered. . Further, a (meth) acrylic monomer may be partially polymerized. When performing the above partial polymerization, chain transfer is performed to control the polymerization reaction of the monomer component and to adjust the weight average molecular weight of the (meth) acrylic monomer and the content of the partial polymer in the entire acrylic syrup. An agent can be added.

  Specific examples of the chain transfer agent include alkyl mercaptans such as t-butyl mercaptan, n-octyl mercaptan and n-dodecyl mercaptan; aromatic mercaptans such as thiophenol and thionaphthol; thioglycolic acid; Thioglycolic acid alkyl esters such as octyl acid, ethylene glycol dithioglycolate, trimethylolpropane tris- (thioglycolate), pentaerythritol tetrakis- (thioglycolate); β-mercaptopropionic acid; alkyl of β-mercaptopropionic acid A thiol compound such as an ester is preferably used, but is not particularly limited. These chain transfer agents may be used alone or in appropriate combination of two or more. What is necessary is just to adjust suitably the usage-amount of the said chain transfer agent according to the weight average molecular weight of the desired (meth) acrylic-type polymer, and is not specifically limited. Here, the weight average molecular weight is measured by gel permeation chromatography (GPC).

  The said (meth) acrylic-type polymer is used in 0-80 weight% in acrylic syrup, Preferably it is 10-60 weight%.

  The acrylic powder (B) constituting the acrylic resin molding materials (D1) and (D2) of the present invention is not particularly limited in shape, but usually has a substantially spherical shape with a particle size of 0.1 μm to 1.0 mm. Used. Although it is used in the range of 50 to 300 parts by weight with respect to 100 parts by weight of acrylic syrup, 70 to 200 parts by weight is preferable. If the amount is less than 50 parts by weight, the desired mechanical strength and transparency cannot be obtained. If the amount exceeds 300 parts by weight, the viscosity becomes high and it becomes difficult to prepare the molding material composition, and the mechanical strength decreases. There is a risk of doing.

  The polymerization initiator (C) used in the acrylic resin molding material (D1) of the present invention is cured by reacting itself or its decomposition product with the active site of (meth) acrylic syrup by heating or the action of a catalyst. It has the effect | action which starts reaction. Although such a polymerization initiator is not specifically limited, The following are illustrated. For example, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butylperoxy-2-ethylhexanoate, t- Amylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 2,4,4-trimethylbenzylperoxy-2-ethylhexanoate, t-butylperoxy-isobutyrate, t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-amylperoxy-3,5,5-trimethylhexanoate, 1,1,3 , 3-Tetramethylbutylperoxy-3,5,5-trimethylhexa 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, t-amylperoxybenzoate, t-amylmene hydroperoxide, cyclohexanone peroxide And organic peroxides such as dicumyl peroxide and bis (4-t-butylcyclohexyl) peroxydicarbonate. Further, azo compounds such as 2,2-azobisisobutyronitrile and 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile are listed. These polymerization initiators may be used alone or in appropriate combination of two or more.

  Although the usage-amount of a polymerization initiator is also selected suitably by the kind of acrylic syrup, it is 0.1-5.0 weight part normally with respect to 100 weight part of acrylic syrup, Preferably it is 0.5-3. 0 part by weight, more preferably 1.0 to 2.0 parts by weight. When the amount used is less than 0.1 parts by weight, the curing is slow, and the high molecular weight and the crosslinking reaction do not proceed sufficiently. Even if it is used in excess of the part, the curing rate does not change and the cost is wasted, and depending on the polymerization initiator, the physical properties may be lowered due to the influence of the plasticizer contained therein.

  As the crosslinking monomer (E) used in the acrylic resin molding material (D2) in the present invention, a polyfunctional (meth) acrylate monomer can be used. Examples of the polyfunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1 1,4-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, dimethylolethane di (meth) acrylate, 1,1-dimethylolpropane di (meth) acrylate, 2,2-di Methylolpropane di (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, neo Nylglycol di (meth) acrylate, polyvalent esters of (meth) acrylic acid and polyhydric alcohols such as polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, divinylbenzene, triaryl isocyanurate, aryl methacrylate, etc. And polyfunctional (meth) acrylate monomers. These may be used alone or in combination of two or more as required.

  The crosslinking monomer (E) is used in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of acrylic syrup, preferably 3 to 40 parts by weight, and more preferably 5 to 30 parts by weight. If it is less than 1 part by weight, the resulting molded product has low heat resistance, and may be deformed when taken out from the mold, resulting in a defective product. In addition, the gloss of the molded product is significantly lost during the cooling process. If it exceeds 50 parts by weight, the molded product becomes hard and brittle, impact resistance is lowered, and there is a possibility that the product will crack and become defective when transported or a hard object falls.

  In the present invention, a fiber reinforcing material (G) such as a pattern material (F) or glass fiber can be further used as desired. Specifically, as the pattern material (F), aluminum hydroxide, silica, glass powder, calcium carbonate, alumina, clay, talc, milled fiber, quartz sand, river sand, diatomaceous earth, mica powder, gypsum, cold water sand, asbestos powder Inorganic fillers such as, and various (color) dyes mixed with various thermoplastic and thermosetting resins and then solidified, and organic materials such as polymer beads.

  The said pattern material may be used independently and may be used in combination of 2 or more types as appropriate. Further, the form of the pattern material such as the average particle diameter is not particularly limited. The blending amount of the pattern material is in the range of 1 to 100 parts by weight and more preferably in the range of 10 to 100 parts by weight with respect to 100 parts by weight of the acrylic syrup. When the amount of the pattern material is less than 1 part by weight, the effect of adding is not exhibited. When the amount of the pattern material exceeds 100 parts by weight, the transparency is lost and the object of the present invention is not achieved. The pattern material may further be subjected to a coupling treatment in order to improve the adhesion with the acrylic syrup interface. Thereby, physical properties, such as impact resistance, intensity | strength, water resistance, etc. of an artificial marble molded object etc. can be improved. These coupling agents are not particularly limited, but include silane coupling agents, chromium coupling agents, titanium coupling agents, aluminum coupling agents, zirconium coupling agents and the like. It is done. Moreover, these may be used independently and may mix and use two or more types suitably.

  Specific examples of the fiber reinforcing material (G) in the present invention include glass fibers, carbon fibers, metal fibers, inorganic fibers such as fibers made of ceramics, organic fibers made of aramid or polyester, natural fibers, and the like. Although it is mentioned, it is not particularly limited. Moreover, although the form of a fiber includes roving, cloth, mat, woven fabric, chopped roving, chopped strand, etc., it is not particularly limited. These fiber reinforcements having a length of 1 to 50 mm are used and may be used singly or may be used by appropriately mixing two or more kinds.

  The fiber reinforcing material is used as desired, and the amount used is not particularly limited as in the case of the pattern material, but is preferably in the range of 1 to 100 parts by weight with respect to 100 parts by weight of acrylic syrup. is there. If the amount is less than 1 part by weight, there is no reinforcing effect. If the amount exceeds 100 parts by weight, the impregnation property is deteriorated, and as a result, sufficient strength properties cannot be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. “Part” indicates “part by weight”, and “%” indicates “% by weight”.

1. Synthesis of acrylic syrup A 3-liter separable four-necked flask equipped with a thermometer, reflux condenser, and metering pump stirrer, methyl methacrylate 1000 g, 1-dodecanethiol as a chain transfer agent (manufactured by Kao Corporation, product (Name “thiocalcol 20”) was introduced. Subsequently, it heated and heated up to 100 degreeC. Under reflux of the content liquid, a solution prepared by dissolving 0.15 g of 2,2-azobisisobutyronitrile in 1000 g of methyl methacrylate was dropped into the reaction vessel at a constant rate over 3 hours to conduct bulk polymerization. went. Heating was continued for 1 hour after completion of the dropping, and then 1 g of 2,6-di-t-butyl-4-methylphenol (trade name “Swanox” manufactured by Seiko Chemical Co., Ltd.) was added as a polymerization inhibitor to stop the polymerization. . Thereafter, the mixture was cooled to room temperature to obtain acrylic syrup. The polymer molecular weight in the acrylic syrup was 200,000 in weight average, the viscosity of the syrup was 200 mPa · s, and the non-volatile content (hereinafter referred to as “NVM”) was 18%. The viscosity is a value measured with a B-type viscometer (Brookfield viscometer) according to JIS-K 6901 (measurement temperature: 25 ° C.).

2. Preparation of acrylic resin molding materials

(1) Acrylic resin molding material 1
100 parts of the acrylic syrup obtained in the above synthesis example, 1 part of a polymerization initiator (Percure HOT), and 150 parts of acrylic powder (molecular weight 100,000, particle size 0.1 mm) are stirred and kneaded with a planetary mixer, and this is a polypropylene film. (Releasable film) covered and stretched to a thickness of about 3 mm, then aged at 40 ° C. for 8 hours to completely dissolve the acrylic powder in the molding material, thereby obtaining an acrylic resin molding material 1 (Compound a-0).

(2) Acrylic resin molding material 2
In the blending of (1) above, an acrylic resin molding material 2 was obtained by the same blending and method as (1) above except that 25 parts of diethylene glycol dimethacrylate was added as a crosslinking monomer (compound a-1). .

(3) Acrylic resin molding material 3
In the blending of (2) above, an acrylic resin molding material 3 was obtained in the same manner as (2) above except that 25 parts of trimethylolpropane trimethacrylate was added as a crosslinking monomer instead of diethylene glycol dimethacrylate ( Compound a-2).

(4) Acrylic resin molding material 4
In the blending of (1) above, an acrylic resin molding material 4 was obtained by the same blending and method as the acrylic resin molding material 1 except that 100 parts of aluminum hydroxide (average particle size 15 μm) was further added (compound b -0).

(5) Acrylic resin molding material 5
An acrylic resin molding material 5 was obtained in the same manner as in the above (4) except that 25 parts of diethylene glycol dimethacrylate was further added as a crosslinking monomer to the blend of (4) (compound b-1).

(6) Acrylic resin molding material 6
In the blending of (5) above, except that the aluminum hydroxide (average particle size 15 μm) was changed to 250 parts, an acrylic resin molding material 6 was obtained in the same manner as (5) above (compound b-2) .

(7) Acrylic resin molding material 7
An acrylic resin molding material 7 was obtained by the same composition and method as in the above (1) except that 50 parts of glass fiber was further added to the above composition (1) (compound c-1).

(8) Acrylic resin molding material 8
An acrylic resin molding material 8 was obtained in the same manner as in (7) above except that 25 parts of diethylene glycol dimethacrylate was added as a crosslinking monomer to the blend of (7) (compound c-1).

(9) Acrylic resin molding material 9
An acrylic resin molding material 9 was obtained in the same manner as in the above (8) except that the glass fiber was changed to 150 parts in the blending of the above (8) (compound c-2).

  The blending of each of the acrylic resin molding materials (ac) is summarized in Table 1 below.

Example 1
Set in a 100-ton press molding machine, set the product a-1 700g from which the release film was removed from the sheet in a 30cm x 30cm flat plate mold set at a product surface temperature of 120 ° C and a back surface temperature of 110 ° C. Molding was performed at a pressure of 8 MPa for 5 minutes. After molding, the mold is opened once, 300 g of compound a-0 is set between the molded product of compound a-1 and the mold on the mold temperature side of 110 ° C., the mold is closed again, and molded at a molding pressure of 8 MPa for 5 minutes. Molded and cooled.

Example 2
In the first molding using the same molding apparatus and mold as used in Example 1, 300 g of Compound a-0 was molded in the same manner as in (1) above. After molding, the mold is opened once, 700 g of Compound a-1 is set between the molded product of Compound a-0 and the mold at the mold temperature of 120 ° C., the mold is closed again, and molded at a molding pressure of 8 MPa for 5 minutes. Molded and cooled.

Example 3
Using the same molding apparatus and mold as used in Example 1 above, heating and pressure molding was performed in the same manner as in Example 1 except that 700 g of compound b-1 was used in the first molding.

Example 4
Using the same molding apparatus and mold as used in Example 1 above, heating and pressure molding were performed in the same manner as in Example 1 except that 700 g of compound c-1 was used in the first molding.

Example 5
The method of Example 1 except that 700 g of compound b-1 is used in the first molding, and 300 g of compound b-0 is used in the second molding using the same molding apparatus and mold as used in Example 1 above. In the same manner as above, heating and pressing were performed.

Example 6
The method of Example 1 except that 700 g of compound c-1 is used in the first molding, and 300 g of compound c-0 is used in the second molding using the same molding apparatus and mold as used in Example 1 above. In the same manner as above, heating and pressing were performed.

Example 7
Heating by the same method as in Example 1 using the same amount of Compound a-0 as in Example 1 except that the temperature of the mold for flat plate is set to a product surface temperature of 140 ° C. and a back surface temperature of 110 ° C.・ Pressurized.

Example 8
Heating by the same method as in Example 1 using the same amount of Compound a-0 as in Example 1 except that the temperature of the flat plate mold is set at a product surface temperature of 115 ° C. and a back surface temperature of 110 ° C.・ Pressurized.

Example 9
The same molding apparatus and mold as used in Example 1 were used in the first molding except that compound a-1 was used in 400 g, and in the second molding, compound a-0 was used in 600 g. It was heated and pressure-molded by the method.

Example 10
The same molding apparatus and mold as used in Example 1 were used in the first molding except that 800g of compound a-1 was used and 200g of compound a-0 was used in the second molding. It was heated and pressure-molded by the method.

Comparative Example 1
Using the same molding apparatus and mold as used in Example 1, the first molding was performed using 1000 g of compound a-0, and the second molding was not performed. It was heated and pressure-molded by the method.

Comparative Example 2
Using the same molding apparatus and mold as used in Example 1, in the first molding, molding was performed using 1000 g of compound b-0, and the second molding was not performed. Heated and pressure molded.

Comparative Example 3
Using the same molding apparatus and mold as used in Example 1, in the first molding, molding was performed using 1000 g of Compound c-0, and the second molding was not performed. Heated and pressure molded.

Comparative Example 4
Using the same molding apparatus and mold as used in Example 1, the first molding was performed using 1000 g of Compound a-1, and the second molding was not performed. Heated and pressure molded.

Comparative Example 5
In the first molding, molding was performed using 1000 g of Compound b-1, and the second molding was not performed, and the heating and pressure molding was performed by the method of Example 1.

Comparative Example 6
In the first molding, molding was performed using 1000 g of compound c-1, and the second molding was not performed, and the heating and pressure molding was performed according to the method of Example 1.

Comparative Example 7
Except for using 700 g of compound b-2 in the first molding, heating and pressure molding were performed by the method of Example 1.

Comparative Example 8
Except for using 700 g of compound c-2 in the first molding, heating and pressure molding were performed by the method of Example 1.

Comparative Example 9
The flat plate mold was heated and pressure-molded by the method of Example 1 except that the product surface temperature was set to 150 ° C and the back surface temperature was set to 140 ° C.

Comparative Example 10
The flat plate mold was heated and pressure-molded by the method of Example 1 except that the product surface temperature was set to 110 ° C and the back surface temperature was set to 100 ° C.

Comparative Example 11
Except for using 400 g of compound a-1 in the first molding and 600 g of compound a-0 in the second molding, heating and pressure molding was performed according to the method of Example 1.

Comparative Example 12
Except for using 800 g of compound a-1 in the first molding and 200 g of compound a-0 in the second molding, heating and pressure molding was performed by the method of Example 1.

  The evaluation items of the molded products obtained by the above examples and comparative examples are described below, and the results are shown in Tables 2-1 and 2-2.

3. Molded product evaluation method

3-1. Mold shrinkage (%) Measured according to JIS K 6911 5.7.3 (1).
After setting the compound in a disk-shaped mold, after heating and compression molding at each set temperature and pressure in the above molding example, take out from the mold and leave it at a temperature of 25 ± 2 ° C. for 24 ± 1 hour Measure the dimensions of a total of four locations (d _{1 to} d ₄ ), two on the front surface and two on the back surface, along the measurement lines orthogonal to each other.
The four outer diameters (D _{1 to} D ₄ ) of the mold groove corresponding to the test piece were measured after treatment under the same conditions, and calculated from the following formula.
MS = 1/4 × ((D ₁ −d ₁ ) / d ₁ + (D ₂ −d ₂ ) / d ₂ + (D ₃ −d ₃ ) / d ₃ + (D ₄ −d ₄ ) / d ₄ )

3-2. Warpage rate (%)
After using a 30 cm × 30 cm flat plate mold, heating and compression molding at each set temperature and pressure in the above molding example, taking out from the mold, and leaving it at a temperature of 25 ± 2 ° C. for 24 ± 1 hour Put it on a horizontal glass plate. A central part of one side of the molded product is pressed onto the glass plate from above with a finger, and the maximum value floating from the glass plate on the diagonal side is read by a gap gauge or the like. The length bmm between the diagonal sides was measured and calculated by (a / b) × 100 (%).

3-3. Appearance 3-3-1. Transparency Transparency was measured with NDH-1001DP (Nippon Denshoku Industries Co., Ltd.) for the total light transmittance of the molded product.
Evaluation ○: 80 or more Δ: 50 to 80
X: 50 or less

3-3-2. The glossiness was determined by measuring the 60 ° gloss of the molded product with a gloss meter: Z-300A (manufactured by Nippon Denshoku Industries Co., Ltd.).
Evaluation ○: 90 or more Δ: 70 to 90
X: 70 or less

3-4. Flexural strength and flexural modulus Measured according to JIS K 7203.
The height h and width W of the test piece are accurately measured to 0.01 mm each using a micrometer. Then 16h support test piece branch distance L _v of ± 0.5 mm, the center of the load was applied at a pressure wedge to measure the load P at which the test piece is broken up 1N.
The size of the test piece used in this evaluation is height h = 6 mm, width W = 10 mm, and length L = 120 mm.
Load speed V (mm / min) is V = h / 2 · t ± 0.2 (t: time 1 min)
Bending strength σ (MPa) = (3PL _v ) / ( ² Wh ² )
Flexural modulus E (MPa) = ((L _v ³ ) / (4 Wh ³ )) × ((F / Y)
F / Y: Slope of the linear part of the load-deflection curve (N / mm)

3-5. Impact Test A flat molded product was cut into a predetermined size, and an impact test was performed in accordance with JIS K 5400 DuPont (8.3.2). The shooting die used had a tip radius of 1/4 inch, the weight used 300 g, and the height at which cracks or cracks occurred was measured at intervals of 5 cm. The maximum height at which no cracks or cracks occurred was determined.

Claims (5)

  100 parts by weight of acrylic syrup (A) comprising 100 to 20% by weight of (meth) acrylic monomer (A1) mainly composed of methyl methacrylate and 0 to 80% by weight of (meth) acrylic polymer (A2) Acrylic resin molding formed by aging a mixture of 50 to 300 parts by weight of acrylic powder (B) and 0.1 to 10 parts by weight of a polymerization initiator (C) at a temperature of 10 to 60 ° C. An acrylic resin molding material (D2) formed by kneading 10 to 50% by weight of a crosslinking monomer (E) in a mixture of the material (D1) and the above (A), (B) and (C) Acrylic resin molding material (D1): Acrylic resin molding material (D2) = 60: 40 to 20:80 (weight ratio) are used together, and molding is performed at a mold temperature of 110 to 140 ° C. and a pressure of 1 to 10 MPa. Acrylic tree characterized by Method of molding products.   The acrylic resin molding material (D2) is molded, and the acrylic resin molding material (D1) is disposed between the obtained molded product and the low-temperature side mold and molded. Molding method for acrylic resin products.   The acrylic resin molding material (D1) is molded, and the acrylic resin molding material (D2) is disposed between the obtained molded product and the high temperature side mold and molded. Molding method for acrylic resin products.   The method for molding an acrylic resin product according to any one of claims 1 to 3, further comprising 1 to 200 parts by weight of a pattern material (F) having a particle size of 0.05 to 100 µm. The method for molding an acrylic resin product according to any one of claims 1 to 4, further comprising 1 to 100 parts by weight of a fiber reinforcing material (G) having a length of 1 to 50 mm.