JP7625824B2 - Molding materials, moldings, and artificial marble - Google Patents

Description

The present invention relates to molding materials, molded products, and artificial marble.

Conventionally, artificial marble products such as countertops, wash basins, and bathtubs have been manufactured by molding and curing resin compositions based on thermosetting resins such as unsaturated polyester resins and vinyl ester resins.

In this context, an unsaturated polyester resin composition that is a mixture of unsaturated polyester, copolymerizable monomer, crosslinkable polymer particles, and inorganic filler has been proposed as a composition suitable for artificial marble with excellent transparency (see, for example, Patent Document 1).

However, in applications requiring higher design quality, the molded products obtained from this composition have problems such as insufficient whiteness, transparency, and image clarity.

Japanese Patent Application Publication No. 9-302009

The problem that the present invention aims to solve is to provide a molding material that can produce molded products that are excellent in whiteness, transparency, gloss, and image clarity, and to provide the molded products and artificial marble produced from the molding material.

As a result of intensive research conducted by the inventors to solve the above problems, they discovered that molded products and artificial marble with excellent whiteness, transparency, gloss, and image clarity can be obtained from molding materials whose essential raw materials are specific polymer components, unsaturated monomers, hardeners, thickeners, inorganic fillers, and glass fibers, and thus completed the present invention.

That is, the present invention relates to a molding material whose essential raw materials are a polymer component (A) containing an unsaturated polyester (a1), an unsaturated monomer (B), a curing agent (C), a thickener (D), an inorganic filler (E) containing a hollow filler (e1) and a glass powder (e2), and glass fibers (F) having a fiber length of 1.5 to 6 mm, characterized in that the inorganic filler (E) is 150 to 400 parts by mass per 100 parts by mass of the total amount of the polymer component (A) and the unsaturated monomer (B), and the hollow filler (e1) in the inorganic filler (E) is 0.3 to 10% by mass.

The molding material of the present invention can be used to obtain molded products with excellent transparency, gloss, and image clarity, and is therefore suitable for use in bathroom components (bathtubs, waterproof pans, counters, walls), wash basin counters, kitchen counters, kitchen sinks, and other housing equipment components.

The molding material of the present invention is a molding material whose essential raw materials are a polymer component (A) containing an unsaturated polyester (a1), an unsaturated monomer (B), a curing agent (C), a thickener (D), an inorganic filler (E) containing a hollow filler (e1) and glass powder (e2), and glass fibers (F) having a fiber length of 1.5 to 6 mm, and the inorganic filler (E) is 150 to 400 parts by mass per 100 parts by mass of the total amount of the polymer component (A) and the unsaturated monomer (B), and the hollow filler (e1) in the inorganic filler (E) is 0.3 to 10% by mass.

The unsaturated polyester (a1) is obtained by reacting a polybasic acid, including an unsaturated polybasic acid, with a polyhydric alcohol.

Examples of the unsaturated polybasic acid include unsaturated dibasic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, and itaconic anhydride. Among these, maleic acid, maleic anhydride, and fumaric acid are preferred because they provide molded products with excellent strength, hot water resistance, toughness, high gloss, high image clarity, and transparency. These unsaturated polybasic acids can be used alone or in combination of two or more.

Examples of the saturated polybasic acid that can be used in combination with the unsaturated polybasic acid include phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, hexahydrophthalic acid, hexahydrophthalic anhydride, hexahydroterephthalic acid, hexahydroisophthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, tetrahydroterephthalic acid, tetrahydroisophthalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, and sucrose. Examples of saturated dibasic acids include phthalic acid, 1,12-dodecanedioic acid, cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid anhydride, and 4,4'-biphenyldicarboxylic acid. Among these, isophthalic acid, terephthalic acid, phthalic acid, and phthalic anhydride are preferred in terms of the strength, hot water resistance, toughness, high gloss, high image clarity, and transparency of the molded product. These saturated polybasic acids can be used alone or in combination of two or more.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, 1,4-butanediol, propylene oxide or ethylene oxide adduct of bisphenol A, 1,2,3,4-tetrahydroxybutane, glycerin, trimer Examples of the polyhydric alcohol include tyrolpropane, 1,3-propanediol, 1,2-cyclohexane glycol, 1,3-cyclohexane glycol, 1,4-cyclohexane glycol, 1,4-cyclohexanedimethanol, paraxylene glycol, bicyclohexyl-4,4'-diol, 2,6-decalin glycol, and 2,7-decalin glycol. Among these, propylene glycol, neopentyl glycol, and hydrogenated bisphenol A are preferred because they provide molded products with excellent strength, water resistance, hot water resistance, toughness, high gloss, and high image clarity. These polyhydric alcohols may be used alone or in combination of two or more.

The weight average molecular weight of the unsaturated polyester (a1) is 5,000 to 40,000, but 7,000 to 35,000 is preferred, and 8,000 to 30,000 is more preferred, since this improves glass fiber impregnation and kneadability after the addition of a thickener, and also provides a viscosity suitable for moldability, resulting in improved appearance of molded products. The weight average molecular weight in the present invention is a value calculated in terms of polystyrene based on gel permeation chromatography (hereinafter abbreviated as "GPC") measurements.

The acid value of the solid content of the unsaturated polyester (a1) is preferably 20 to 40 mgKOH/g, since the initial thickening behavior is gentle, the glass fiber impregnation and kneading properties are improved after the addition of the thickener, a viscosity suitable for molding is obtained, and the appearance of the molded product is improved. The acid value in the present invention is a value obtained by a measurement method conforming to JIS K6901 (2018) 5.3.2.

The present invention contains the unsaturated polyester (a1) as the polymer component, but other polymer components such as vinyl ester (a2) can be used in combination.

The vinyl ester (a2) is obtained by reacting an epoxy resin with (meth)acrylic acid.

Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol fluorene type epoxy resins, and biscresol fluorene type epoxy resins; novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins; oxazolidone modified epoxy resins; brominated epoxy resins of these resins; glycidyl ethers of phenols such as dipropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of alkylene oxide adducts of bisphenol A, and glycidyl ethers of polyhydric alcohols such as diglycidyl ether of hydrogenated bisphenol A; Examples of the epoxy resin include alicyclic epoxy resins such as 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate and 1-epoxyethyl-3,4-epoxycyclohexane, glycidyl esters such as phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, diglycidyl-p-oxybenzoic acid, and dimer acid glycidyl ester, glycidyl amines such as tetraglycidyldiaminodiphenylmethane, tetraglycidyl-m-xylenediamine, triglycidyl-p-aminophenol, and N,N-diglycidylaniline, and heterocyclic epoxy resins such as 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate. Among these, bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferred because they improve the balance between the fluidity of the molding material during molding and the strength, transparency, and gloss of the molded product. These epoxy resins can be used alone or in combination of two or more.

The epoxy equivalent of the epoxy resin is preferably 220 to 470, as this will further improve the toughness of the molded product.

From the viewpoint of the balance between low shrinkage, transparency, gloss, and image clarity, the content of the unsaturated polyester (a1) in the polymer component (A) is preferably in the range of 50 to 100% by mass, and more preferably in the range of 60 to 100% by mass.

From the viewpoint of the balance between low shrinkage and transparency, gloss, and image clarity, the vinyl ester (a2) in the polymer component (A) is preferably in the range of 0 to 50% by mass, and more preferably in the range of 0 to 40% by mass.

The polymer component (A) in the molding material of the present invention is preferably 10 to 30% by mass from the viewpoint of the balance between low shrinkage, transparency, gloss, and image clarity.

Examples of the unsaturated monomer (B) include styrene, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate alkyl ether, polypropylene glycol (meth)acrylate alkyl ether, 2-ethylhexyl methacrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isotridecyl (meth)acrylate, n-stearyl (meth)acrylate, tetrahydrofurfuryl methacrylate, isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, Monofunctional (meth)acrylate compounds such as methacrylate, dicyclopentanyl methacrylate, hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate; di(meth)acrylate compounds such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol di(meth)acrylate, and 1,4-cyclohexanedimethanol di(meth)acrylate; vinyl toluene, α-methylstyrene, diallyl phthalate, and divinyl benzene; and among these, styrene is preferred because the molded product has better heat resistance, water resistance, chemical resistance, and transparency. These unsaturated monomers can be used alone or in combination of two or more.

The unsaturated monomer (B) in the molding material of the present invention is preferably 4 to 10% by mass from the viewpoint of the balance between low shrinkage, transparency, gloss, and image clarity.

From the viewpoint of the balance between low shrinkage, transparency, gloss, and image clarity, the mass ratio (A/B) of the polymer component (A) to the unsaturated monomer (B) is preferably in the range of 80/20 to 60/40, and more preferably in the range of 75/25 to 65/35.

The refractive index of the cured product of the resin composition consisting of the polymer component (A) and the unsaturated monomer (B) is preferably 1.54 to 1.59, since this further improves the transparency of the molded product.

The curing agent (C) is not particularly limited, but is preferably an organic peroxide, such as a diacyl peroxide compound, a peroxy ester compound, a hydroperoxide compound, a ketone peroxide compound, an alkyl perester compound, a percarbonate compound, or a peroxy ketal, and can be appropriately selected according to the molding conditions. These curing agents (C) can be used alone or in combination of two or more kinds.

The amount of the curing agent (C) is preferably 0.3 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the total amount of the polymer component (A) and the unsaturated monomer (B).

Examples of the thickener (D) include metal oxides and hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide, and isocyanate compounds. Magnesium oxide is preferred because it improves the balance between the handleability and moldability of the molding material, such as film peelability and finger touch. These thickeners (D) can be used alone or in combination of two or more kinds.

The thickener (D) is preferably present in an amount of 0.3 to 5 parts by mass, and more preferably 0.5 to 2.5 parts by mass, per 100 parts by mass of the total of the polymer component (A) and the unsaturated monomer (B), because this improves the in-mold fluidity of the molding material.

By using the hollow filler (e1) and the glass powder (e2) as the inorganic filler (E), a molded product having both excellent whiteness and transparency can be obtained.

Examples of the hollow filler (e1) include glass balloons, silica balloons, alumina balloons, etc., but glass balloons are preferred because they improve the transparency of the molded product.

The average particle size (median particle size) of the hollow filler (e1) is preferably 50 μm or less, and more preferably 40 μm or less, since this further improves the gloss and image clarity of the molded product.

The hollow filler (e1) in the inorganic filler (E) is 0.3% by mass or more, preferably 0.5% by mass or more, and more preferably 0.7% by mass or more, from the viewpoint of the whiteness and transparency of the molded product.

The hollow filler (e1) in the inorganic filler (E) is 10% by mass or less, preferably 8% by mass or less, and more preferably 5% by mass or less, from the viewpoints of productivity due to an increase in the viscosity of the molding material, and gloss and image clarity of the molded product.

Examples of the glass powder (e2) include glass frit, milled fiber, glass powder, etc., but glass frit is preferred because it further improves the transparency, gloss, and image clarity of the molded product.

The average particle size of the glass powder (e2) is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 13 μm or less, since this improves the image clarity and gloss of the molded product.

The inorganic filler (E) may be a filler (e3) other than the hollow filler (e1) and the glass powder (e2), and examples of such fillers include aluminum hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, silica, silica sand, gypsum, alumina, gypsum sand, gypsum sand, and titanium oxide. These inorganic fillers (E) may be used alone or in combination of two or more.

The refractive index of the inorganic filler (E) is preferably 1.54 to 1.59, as this further improves the transparency of the molded product.

The inorganic filler (E) is preferably 150 to 400 parts by mass, more preferably 200 to 350 parts by mass, and even more preferably 250 to 350 parts by mass, per 100 parts by mass of the total of the polymer component (A) and the unsaturated monomer (B), because this further improves the appearance and smoothness of the molded product.

The glass fibers (F) used have a fiber length of 1.5 to 6 mm or less, but 1.5 to 3 mm or less is more preferable because this improves the gloss and image clarity of the molded product.

The filament diameter of the glass fiber (F) is preferably 5 to 15 μm, as this further improves the gloss and image clarity of the molded product.

The glass fiber (F) in the molding material is preferably 1 to 17% by mass, and more preferably 1 to 12% by mass, since this further improves the gloss and image clarity of the molded product.

The molding material may contain various additives such as shrinkage reducing agents, polymerization inhibitors, colorants, UV absorbers, viscosity reducers, antioxidants, flame retardants, surfactants, water repellents, and oil repellents in addition to the essential components described above.

The content of the low shrinkage agent, such as cross-linked polystyrene, in the molding material is preferably 15% by mass or less, and more preferably 10% by mass or less, of the total amount of the resin and low shrinkage agent components, since this further improves the transparency of the molded product.

The molding material of the present invention is preferably a bulk molding compound (BMC) since this improves the handling and moldability of the molding material.

The method for producing the BMC includes mixing the polymer component (A), the unsaturated monomer (B), the curing agent (C), the thickener (D), the inorganic filler (E), the glass fiber (F), and, if necessary, a shrinkage reducing agent, an internal mold release agent, etc., using a mixer such as a normal roll, an intermixer, a planetary mixer, a kneader, or an extruder.

The artificial marble of the present invention is obtained from the above molding material, but the preferred molding method is the hot compression molding method of BMC, as this improves the handling and moldability of the molding material.

The hot compression molding method involves, for example, weighing out a predetermined amount of molding material such as BMC, pouring it into a mold that has been preheated to 100-180°C, clamping the mold with a compression molding machine, imitating the molding material, and maintaining a molding pressure of 1-20 MPa to harden the molding material, and then removing the molded product to obtain the artificial marble. In this case, a preferred manufacturing method is to perform hot compression molding in a mold with a share edge, at a mold temperature of 110-160°C, and maintaining a molding pressure of 5-15 MPa for the specified time of 1-2 minutes per 1 mm of artificial marble thickness.

The artificial marble of the present invention has excellent transparency, gloss, and image clarity, and can therefore be suitably used for bathroom components (bathtubs, waterproof pans, counters, walls), washbasin counters, kitchen counters, kitchen sinks, and other housing equipment components, as well as building components such as walls and floors.

The present invention will be described in more detail below with reference to specific examples. The acid value of the resin was measured in accordance with JIS K6901 (2018) 5.3.2, and the weight average molecular weight was measured under the following GPC measurement conditions.

[GPC measurement conditions]
Measurement device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were used, connected in series.
"TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 "TSKgel G2000" (7.8mm I.D. x 30cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (sample concentration 4 mg/mL in tetrahydrofuran solution)
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(monodisperse polystyrene)
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
Tosoh Corporation "TSKgel Standard Polystyrene A-5000" 1
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

(Synthesis Example 1: Synthesis of Unsaturated Polyester Resin (1))
A 2L glass flask equipped with a nitrogen gas inlet tube, a thermometer, a reflux condenser, and a stirrer was charged with 208 parts by mass of neopentyl glycol, 53 parts by mass of propylene glycol, 264 parts by mass of hydrogenated bisphenol A, and 290 parts by mass of isophthalic acid, and heating was started under a nitrogen stream. At an internal temperature of 215°C, a dehydration condensation reaction was carried out in a conventional manner, and when the solid acid value reached 5 (mgKOH/g), the mixture was cooled to 190°C. Next, 196 parts by mass of maleic acid was added to continue the dehydration condensation reaction, and when the solid acid value reached 29 (mgKOH/g), 0.4 parts by mass of toluhydroquinone was added. The unsaturated polyester (a1-1) was dissolved in styrene monomer so that the concentration was 70% by mass, and an unsaturated polyester resin (1) was obtained. The weight average molecular weight of the unsaturated polyester (a1-1) was 10,000. The refractive index of the unsaturated polyester resin (1) was 1.55.

(Synthesis Example 2: Synthesis of vinyl ester resin (1))
In a 2L flask equipped with a nitrogen inlet tube, a thermometer, and a stirrer, 246 parts by mass of epoxy resin (DIC Corporation's "Epicron 860-C", bisphenol A type epoxy resin, epoxy equivalent 240), 750 parts by mass of epoxy resin (DIC Corporation's "Epicron 1050", bisphenol A type epoxy resin, epoxy equivalent 470), 214 parts by mass of methacrylic acid, and 0.42 parts by mass of dibutylhydroxytoluene were added, and the temperature was raised to 100°C under a gas flow in which nitrogen and air were mixed in a 1:1 ratio. 0.97 parts by mass of 2-methylimidazole was added thereto, and the temperature was raised to 110°C to carry out a reaction. When the solid acid value became 6 (mgKOH/g) or less, 0.48 parts by mass of toluhydroquinone was added, and the vinyl ester (a2-1) was dissolved in styrene monomer so that the concentration was 70% by mass, to obtain a vinyl ester resin (1). The epoxy equivalent of the epoxy resin of this vinyl ester (a2-1) was 380. The refractive index of the vinyl ester resin (1) was 1.58.

(Production Example 1: Production of handle material)
A compound was obtained by kneading 100 parts by mass of a styrene solution of unsaturated polystyrene resin (styrene content 40% by mass), 250 parts by mass of aluminum hydroxide, 5 parts by mass of a white colorant, 1 part by mass of a curing agent, and 2 parts by mass of a curing accelerator. The compound obtained above was poured into a metal tray with a thickness of 15 mm, cured at room temperature for 24 hours, and then heated and cured for another 3 hours in a dryer at 80°C to obtain a cured product made of the compound. The cured product was coarsely crushed with a shear type crusher, further finely crushed with a pin mill type crusher, and then passed through 165 mesh and 28 mesh metal mesh sieves (JIS Z8801-1) to obtain a white granular material with a particle size of 100 to 600 μm.

(Example 1: Production and evaluation of molding material (1))
100 parts by mass of unsaturated polyester resin (1), 0.5 parts by mass of colorant ("PT6885" manufactured by Mikuni Color Co., Ltd., white polyester toner), 1.2 parts by mass of curing agent ("Perhexa HC" manufactured by NOF Corporation), 3 parts by mass of hollow filler ("3M Glass Bubbles S32-HS" manufactured by 3M Japan Ltd., glass balloon, average particle size 25 μm; hereinafter abbreviated as "hollow filler (e1-1)"), 317 parts by mass of glass powder ("CF0017-05C06" manufactured by Takara Standard Co., Ltd., glass frit, average particle size 6 to 7 μm, refractive index 1.55; hereinafter abbreviated as "glass powder (e2-1)"), 2 parts by mass of internal release agent (zinc stearate), 1.3 parts by mass of thickener (magnesium oxide), and glass fiber ("Chopped Strand" manufactured by Central Glass Fiber Co., Ltd. ECS03-670, fiber length 3.0 mm, refractive index 1.55) were mixed and kneaded in a planetary mixer, and then aged at 40° C. for 24 hours to obtain molding material (1) as BMC.

[Production of molded product (artificial marble)]
Compression molding was carried out under the following conditions to obtain a molded product (1) as a flat plate of artificial marble measuring 300 mm x 300 mm x 7 mm.
Molding temperature: 130℃ (molded product side), 115℃ (back side)
Molding pressure: 10 MPa
Pressurization time: 480 seconds

[Evaluation of Whiteness]
The whiteness (L value) of the molded article (1) obtained above was measured using a "BYK spectro-guide 45/0 gloss" manufactured by BYK Corporation, and the whiteness was evaluated according to the following criteria.
◎: L value is 85 or more. ○: L value is 80 or more and less than 85. △: L value is 75 or more and less than 80. ×: L value is less than 75.

[Transparency evaluation]
The molded article (1) obtained above was visually observed to confirm the visibility of the pattern material on the surface and in the depth direction, and the transparency was evaluated according to the following criteria.
◎: The pattern material is clearly visible on the surface and inside of the molded product. ○: The pattern material is clearly visible on the surface and inside of the molded product. △: The pattern material is slightly visible on the surface and inside of the molded product. ×: Only the pattern material on the surface of the molded product is visible.

[Evaluation of Gloss]
For the molded article (1) obtained above, the reflectance of 0 to 2000 GU was measured at an incident angle of 20° using a "BYK Gardner micro-TRI-gloss" manufactured by BYK Corporation. The value was taken as the 20° gloss value, and the gloss was evaluated according to the following criteria.
◎: 20° gloss value is 80 or more. ○: 20° gloss value is 75 or more and less than 80. △: 20° gloss value is 70 or more and less than 75. ×: 20° gloss value is less than 70.

[Evaluation of image clarity]
The image clarity (DOI) of the molded product (1) obtained above was measured using a Rhopoint IQ-s manufactured by Konica Minolta, Inc., and the image clarity was evaluated according to the following criteria.
◎: DOI is 90 or more. ○: DOI is 80 or more and less than 90. △: DOI is 70 or more and less than 80. ×: DOI is less than 70.

(Examples 2 to 13: Production and evaluation of molding materials (2) to (13))
Except for changing the compounding compositions to those shown in Tables 1 to 3, molding materials (2) to (13) and molded articles (2) to (13) were produced in the same manner as in Example 1, and various performances were evaluated.

(Comparative Examples 1 to 3: Production and Evaluation of Molding Materials (R1) to (R3))
Except for changing the compounding composition to that shown in Table 4, molding materials (R1) to (R3) and molded products (R1) to (R3) were produced in the same manner as in Example 1, and various performances were evaluated. In Comparative Example 1, BMC was not obtained due to high viscosity.

The compositions and evaluation results of the molding materials (1) to (13) obtained above are shown in Tables 1 to 3.

The compositions and evaluation results of the molding materials (R1) to (R3) obtained above are shown in Table 4.

The raw materials in the table are as follows:
Wetting and dispersing agent: BYK "BYK-9010"
Low shrinkage agent: "Staphyloid GS-102R" manufactured by Aica Kogyo Co., Ltd.; cross-linked polystyrene resin powder with aluminum hydroxide surface treatment Hollow filler (e1-2): "3M Glass Bubbles S60-HS" manufactured by 3M Japan Co., Ltd.; glass balloon, average particle size 24 μm
Hollow filler (e1-3): "3M Glass Bubbles K46" manufactured by 3M Japan Co., Ltd.; glass balloon, average particle size 40 μm
Other fillers (e3-1): "CW-308" manufactured by Sumitomo Chemical Co., Ltd.; aluminum hydroxide, average particle size 10 μm, refractive index 1.57
Other fillers (e3-2): "Softon 1200" manufactured by Bihoku Funka Kogyo Co., Ltd.; calcium carbonate, average particle size 1.8 μm, refractive index 1.63

The molded products obtained from the molding materials of Examples 1 to 13 were confirmed to have excellent whiteness, transparency, gloss, and image clarity.

Comparative Example 1 is an example in which the content of hollow filler (e1) in inorganic filler (E) is greater than 10 mass%, which is the upper limit of the present invention, but it was confirmed that a molding material could not be produced due to high viscosity.

Comparative Example 2 is an example that does not contain hollow filler (e1), which is an essential component of the present invention, and it was confirmed that the whiteness of the molded product was insufficient.

Comparative Example 3 is an example that does not contain glass powder (e2), which is an essential component of the present invention, but it was confirmed that the transparency of the molded product was insufficient.

Claims (5)

A molding material containing as essential raw materials a polymer component (A) containing an unsaturated polyester (a1), an unsaturated monomer (B), a curing agent (C), a thickener (D), an inorganic filler (E) containing a hollow filler (e1) and a glass powder (e2), and glass fibers (F) having a fiber length of 1.5 to 6 mm, wherein the polymer component (A) is 10 to 30 mass %, the unsaturated monomer (B) is 4 to 10 mass %, and the glass fibers (F) are 1 to 17 mass %, and the polymer component (A) and the unsaturated monomer (B) are mixed together to form a molding material. the curing agent (C) is 0.3 to 5 parts by mass, the thickener (D) is 0.3 to 5 parts by mass, the inorganic filler (E) is 150 to 400 parts by mass, the unsaturated polyester (a1) in the polymer component (A) is 50 to 100% by mass, the hollow filler (e1) in the inorganic filler (E) is 0.3 to 10% by mass, and the glass powder (e2) is 59.375 to 99.0625% by mass, relative to 100 parts by mass of a total amount of the body (B). The molding material according to claim 1, wherein the hollow filler (e1) has an average particle size of 50 μm or less. The molding material according to claim 1 or 2, wherein the thickener (D) is magnesium oxide. A molded product made using the molding material described in any one of claims 1 to 3. Artificial marble made using the molding material according to any one of claims 1 to 3.