Unsaturated polyester resin composition, molding material, and molded article

Abstract

To provide an unsaturated polyester resin composition that exhibits excellent flame retardancy and is capable of uniformly dispersing a powdery flame retardant, a molding material containing the unsaturated polyester resin composition, and a molded article containing a cured product of the molding material.SOLUTION: An unsaturated polyester resin raw material comprises: a resin component containing an unsaturated polyester, a polymerizable monomer, and a low-shrinkage agent; a powdery flame retardant; and aluminum hydroxide. The low-shrinkage agent contains a styrene-based thermoplastic elastomer comprising a styrene-conjugated diene copolymer and / or a hydrogenated product thereof. The content of the styrene-based thermoplastic elastomer is 2 pts.mass or more and 18 pts.mass or less relative to 100 pts.mass of the resin component.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an unsaturated polyester resin composition, a molding material, and a molded article. [Background technology]

[0002] Conventionally, molded articles made of molding materials containing unsaturated polyester resin compositions (particularly, sheet molding compounds (SMC), bulk molding compounds (BMC), and thick molding compounds (TMC)) have been used in a wide range of fields due to their excellent mechanical properties, water resistance, and corrosion resistance.

[0003] As such an unsaturated polyester resin composition, for example, a resin composition containing an unsaturated polyester resin, a shrinkage reducing agent (polystyrene and polyethylene), and a flame retardant (phosphorus-based flame retardant and nitrogen-based flame retardant) has been proposed (see, for example, Example 9 of Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 264661 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, when the flame retardant is in a powder form, the flame retardant may separate from the unsaturated polyester resin and the low shrinkage agent, resulting in a non-uniform flame retardant. It has been found that the non-uniform flame retardant causes problems such as a decrease in production efficiency and a non-uniform flame retardancy in a molded product obtained using the unsaturated polyester resin composition.

[0006] The present invention provides an unsaturated polyester resin composition which has excellent flame retardancy and is capable of uniformly dispersing a powdery flame retardant, a molding material containing the unsaturated polyester resin composition, and a molded article containing a cured product of the molding material. [Means for solving the problem]

[0007] The present invention [1] is an unsaturated polyester resin composition comprising a resin component including an unsaturated polyester, a polymerizable monomer, and a low profile agent, a powdery flame retardant, and aluminum hydroxide, the low profile agent including a styrene-based thermoplastic elastomer consisting of a styrene-conjugated diene copolymer and / or a hydrogenated product thereof, the content of the styrene-based thermoplastic elastomer being 2 parts by mass or more and 18 parts by mass or less per 100 parts by mass of the resin component.

[0008] The present invention [2] includes the unsaturated polyester resin composition according to the above [1], in which the powdery flame retardant includes a phosphorus-based flame retardant and / or a nitrogen-based flame retardant.

[0009] The present invention [3] includes the unsaturated polyester resin composition according to the above [1] or [2], in which the styrene-based thermoplastic elastomer includes a hydrogenated product of a styrene-conjugated diene block copolymer.

[0010] The present invention [4] includes a molding material containing the unsaturated polyester resin composition according to any one of the above [1] to [3] and reinforcing fibers.

[0011] The present invention [5] includes a molded article comprising a cured product of the molding material described in [4] above. Effect of the Invention

[0012] The unsaturated polyester resin composition of the present invention contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with a powdery flame retardant, and therefore has excellent flame retardancy and can disperse the powdery flame retardant uniformly.

[0013] The molding material of the present invention contains the unsaturated polyester resin composition of the present invention, and therefore such a molding material has excellent flame retardancy and can uniformly disperse a powdery flame retardant therein.

[0014] The molded article of the present invention contains a cured product of the molding material of the present invention, and therefore has excellent flame retardancy and can uniformly disperse a powdery flame retardant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The unsaturated polyester resin composition is prepared by preparing an unsaturated polyester resin raw material (described later) and then blending aluminum hydroxide therewith (first embodiment), or by blending a resin component containing an unsaturated polyester, a polymerizable monomer, and a shrinkage reducing agent, a powdery flame retardant, and aluminum hydroxide all at once (second embodiment).

[0016] 1. First embodiment In the first embodiment, the unsaturated polyester resin composition is prepared by preparing an unsaturated polyester resin raw material and then blending aluminum hydroxide. In such a case, the unsaturated polyester resin composition contains an unsaturated polyester resin raw material and aluminum hydroxide.

[0017] <Unsaturated polyester resin raw material> The unsaturated polyester resin raw material contains a resin component and a powdery flame retardant. The unsaturated polyester resin raw material is preferably composed of a resin component and a powdery flame retardant. The resin component contains an unsaturated polyester, a polymerizable monomer, a shrinkage reducing agent, and, if necessary, other thermosetting resins (excluding unsaturated polyester resins).

[0018] <Unsaturated polyester> The unsaturated polyester is obtained by reacting a polybasic acid with a polyhydric alcohol.

[0019] [Polybasic acid] The polybasic acid includes a polybasic acid having an ethylenically unsaturated double bond as an essential component (hereinafter referred to as an ethylenically unsaturated bond-containing polybasic acid) and a polybasic acid not having an ethylenically unsaturated double bond as an optional component (hereinafter referred to as an ethylenically unsaturated bond-free polybasic acid).

[0020] (Polybasic acid containing ethylenically unsaturated bonds) Examples of the ethylenically unsaturated bond-containing polybasic acid include ethylenically unsaturated aliphatic dibasic acids and their anhydrides, halides of ethylenically unsaturated aliphatic dibasic acids, and alkyl esters of ethylenically unsaturated aliphatic dibasic acids.

[0021] Examples of ethylenically unsaturated aliphatic dibasic acids include maleic acid, fumaric acid, itaconic acid, and dihydromuconic acid. Examples of ethylenically unsaturated bond-containing polybasic acids include acid anhydrides derived from the above ethylenically unsaturated aliphatic dibasic acids. Examples of ethylenically unsaturated bond-containing polybasic acids include maleic anhydride. Examples of ethylenically unsaturated bond-containing polybasic acids include maleic anhydride and fumaric acid.

[0022] (Polybasic acid not containing ethylenically unsaturated bonds) Examples of polybasic acids not containing ethylenically unsaturated bonds include saturated aliphatic polybasic acids, saturated alicyclic polybasic acids, aromatic polybasic acids, anhydrides of these acids, halides of these acids, and alkyl esters of these acids.

[0023] Examples of the saturated aliphatic polybasic acid include saturated aliphatic dibasic acids.

[0024] Examples of saturated aliphatic dibasic acids include oxalic acid, malonic acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, hexylsuccinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylsuccinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Examples of saturated aliphatic polybasic acids include acid anhydrides derived from the above-mentioned saturated aliphatic dibasic acids. Examples of acid anhydrides derived from saturated aliphatic dibasic acids include oxalic anhydride and succinic anhydride.

[0025] Examples of the saturated alicyclic polybasic acid include saturated alicyclic dibasic acids.

[0026] Examples of saturated alicyclic dibasic acids include HET acid, 1,2-hexahydrophthalic acid, 1,1-cyclobutanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid (cis- or trans-1,4-cyclohexanedicarboxylic acid or a mixture thereof). Examples of saturated alicyclic polybasic acids include acid anhydrides derived from the above-mentioned saturated alicyclic dibasic acids. Examples of acid anhydrides derived from saturated alicyclic dibasic acids include HET acid anhydride.

[0027] Examples of aromatic polybasic acids include aromatic dibasic acids.

[0028] Examples of aromatic dibasic acids include phthalic acid (orthophthalic acid, isophthalic acid, terephthalic acid), trimellitic acid, and pyromellitic acid. Examples of aromatic polybasic acids include acid anhydrides derived from the above aromatic dibasic acids. Examples of acid anhydrides derived from aromatic dibasic acids include phthalic anhydride.

[0029] The polybasic acids can be used alone or in combination of two or more kinds.

[0030] When the polybasic acid includes an ethylenically unsaturated bond-containing polybasic acid and an ethylenically unsaturated bond-free polybasic acid, the content of the ethylenically unsaturated bond-containing polybasic acid is, for example, 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and, for example, 100 mol% or less, preferably 90 mol% or less, based on 100 mol of the total polybasic acid. The content of the ethylenically unsaturated bond-free polybasic acid is, for example, 0 mol% or more, preferably 10 mol% or more, and, for example, 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less.

[0031] The polybasic acid preferably does not include a polybasic acid not containing an ethylenically unsaturated bond, but is composed of a polybasic acid containing an ethylenically unsaturated bond.

[0032] [Polyhydric alcohol] Polyhydric alcohols include, for example, dihydric and trihydric alcohols.

[0033] Examples of dihydric alcohols include aliphatic diols, alicyclic diols, and aromatic diols. Examples of aliphatic diols include alkanediols and ether diols. Examples of alkanediols include alkanediols having 2 to 10 carbon atoms. Examples of alkanediols having 2 to 10 carbon atoms include ethylene glycol, propylene glycol (1,2- or 1,3-propanediol or a mixture thereof), butylene glycol (1,2- or 1,3- or 1,4-butylene glycol or a mixture thereof), 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, and 3,3-dimethylolheptane. Examples of ether diols include diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of alicyclic diols include cyclohexanediol (1,2- or 1,3- or 1,4-cyclohexanediol or a mixture thereof), cyclohexanedimethanol (1,2- or 1,3- or 1,4-cyclohexanedimethanol or a mixture thereof), cyclohexanediethanol (1,2- or 1,3- or 1,4-cyclohexanediethanol or a mixture thereof), and hydrogenated bisphenol A. Examples of aromatic diols include an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A.

[0034] Examples of trihydric alcohols include glycerin, trimethylolpropane, and triisopropanolamine.

[0035] As the polyhydric alcohol, preferably, a dihydric alcohol is used. As the polyhydric alcohol, more preferably, an aliphatic diol is used. As the polyhydric alcohol, further preferably, an alkanediol having 2 to 10 carbon atoms is used. As the polyhydric alcohol, particularly preferably, an alkanediol is used. As the polyhydric alcohol, most preferably, propylene glycol is used.

[0036] The polyhydric alcohols can be used alone or in combination of two or more kinds.

[0037] [Reaction of polybasic acids with polyhydric alcohols] Unsaturated polyesters are prepared by reacting a polybasic acid with a polyhydric alcohol.

[0038] The equivalent ratio of the polyhydric alcohol to the polybasic acid (hydroxyl groups of the polyhydric alcohol / carboxyl groups of the polybasic acid) is, for example, 0.9 or more, preferably 0.95 or more, and for example, 1.2 or less, preferably 1.1 or less.

[0039] The reaction temperature is, for example, 150° C. or more, preferably 190° C. or more, and for example, 250° C. or less, preferably 230° C. or less.

[0040] In the above reaction, a known solvent, a known reaction catalyst and a known additive can be added, if necessary.

[0041] This allows the preparation of unsaturated polyesters, which can also be modified with dicyclopentadiene (DCPD).

[0042] The acid value of the unsaturated polyester (measurement method: in accordance with JIS K6901 (2008)) is, for example, 10 mgKOH / g or more, preferably 15 mgKOH / g or more, more preferably 20 mgKOH / g or more, and for example, less than 40 mgKOH / g, preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less.

[0043] The weight average molecular weight of the unsaturated polyester is, for example, 2,000 or more, preferably 4,000 or more, and for example, 25,000 or less, preferably 20,000 or less.

[0044] The weight average molecular weight is a weight average molecular weight calculated in terms of polystyrene by GPC (gel permeation chromatography).

[0045] The unsaturated polyesters can be used alone or in combination of two or more kinds.

[0046] The content of the unsaturated polyester is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, and for example, 60 parts by mass or less, preferably 50 parts by mass or less, and more preferably 40 parts by mass or less, per 100 parts by mass of the resin component.

[0047] <Polymerizable monomer> Examples of the polymerizable monomer include styrene-based monomers and (meth)acrylic acid ester-based monomers.

[0048] Styrenic monomers include, for example, styrene, vinyltoluene, t-butylstyrene, and chlorostyrene.

[0049] Examples of (meth)acrylic acid ester monomers include (meth)acrylic acid alkyl esters, (meth)acrylic acid allyl esters, ring-containing (meth)acrylic acid esters, (meth)acrylic acid hydroxyalkyl esters, (meth)acrylic acid alkoxyalkyl esters, (meth)acrylic acid aminoalkyl esters, (meth)acrylic acid fluoroalkyl esters, and polyfunctional (meth)acrylic acid esters. Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. Examples of (meth)acrylic acid allyl esters include allyl (meth)acrylate. Examples of ring-containing (meth)acrylic acid esters include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Examples of hydroxyalkyl (meth)acrylic acid esters include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Examples of alkoxyalkyl (meth)acrylic acid esters include 2-methoxyethyl (meth)acrylate and 2-ethoxyethyl (meth)acrylate. Examples of aminoalkyl (meth)acrylic acid esters include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and chloride salts thereof. Examples of the fluoroalkyl (meth)acrylate include trifluoroethyl (meth)acrylate and heptadecafluorodecyl (meth)acrylate.Examples of polyfunctional (meth)acrylic acid esters include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0050] As the polymerizable monomer, preferably, styrene-based monomer and (meth)acrylic acid alkyl ester are mentioned. As the polymerizable monomer, more preferably, styrene and methyl methacrylate are mentioned. As the polymerizable monomer, more preferably, styrene is mentioned.

[0051] The polymerizable monomers can be used alone or in combination of two or more kinds.

[0052] The content ratio of the polymerizable monomer relative to 100 parts by mass of the resin component is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass or less.

[0053] <Low shrinkage agent> When a molded article is obtained using this unsaturated polyester resin raw material, the low shrinkage agent is blended in order to suppress cure shrinkage and heat shrinkage of the molded article and to improve the appearance.

[0054] [Styrene-based thermoplastic elastomer] The low profile agent includes a styrene-based thermoplastic elastomer consisting of a styrene-conjugated diene copolymer and / or a hydrogenated product thereof.

[0055] The styrene-based thermoplastic elastomer suppresses the above-mentioned thermal shrinkage and improves the dispersibility of the powdered flame retardant in the raw material unsaturated polyester resin.

[0056] Examples of the styrene-conjugated diene copolymer include a styrene-butadiene copolymer elastomer, a styrene-isoprene copolymer elastomer, a styrene-butadiene-styrene copolymer elastomer, and a styrene-isoprene-styrene copolymer elastomer. Examples of the styrene-conjugated diene copolymer include a styrene-butadiene-styrene copolymer elastomer ...

[0057] Examples of the hydrogenated styrene-conjugated diene copolymer include styrene-ethylene-butylene copolymer elastomer, styrene-ethylene-propylene copolymer elastomer, styrene-ethylene-butylene-styrene copolymer elastomer, and styrene-ethylene-propylene-styrene copolymer elastomer. Examples of the hydrogenated styrene-conjugated diene copolymer include preferably styrene-ethylene-propylene-styrene copolymer elastomer, styrene-ethylene-butylene-styrene copolymer elastomer, and styrene-ethylene-propylene copolymer elastomer.

[0058] The copolymer includes a block copolymer or a random copolymer, and preferably includes a block copolymer.

[0059] As the styrene-conjugated diene copolymer and its hydrogenated product, commercially available products can also be used. Examples of such commercially available products include D1101, D1102, D1155, DKX405, DX410, DX415, D1192, D1161, D1171, G1651, G1652, G1654, G1701, G1730, and 8004 (all manufactured by Kraton Elastomers), Asaprene T411, Asaprene T432, Tufprene A, Tufprene 125, Tufprene 126S, Tuftec H1041, Tuftec H1043, and Tuftec H1052 (all manufactured by Asahi Kasei Corporation), the Septon series (e.g., Septon 2002, 4033, and 8004 manufactured by Kuraray Co., Ltd.), and the Hybler series (e.g., Hybler 5125 manufactured by Kuraray Co., Ltd.).

[0060] As the styrene-based thermoplastic elastomer, from the viewpoint of improving the appearance of a molded article obtained by using an unsaturated polyester resin raw material (suppressing uneven gloss), a hydrogenated product of a styrene-conjugated diene block copolymer is preferably used.

[0061] The styrene content in the styrene-based thermoplastic elastomer is, for example, 5% or more and, for example, 50% or less.

[0062] The number average molecular weight of the styrene-based thermoplastic elastomer is, from the viewpoint of low shrinkage and dispersibility, for example, 10,000 or more, preferably 30,000 or more, and for example, 500,000 or less, preferably 200,000 or less.

[0063] The number average molecular weight is a weight average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC).

[0064] The content of the styrene-based thermoplastic elastomer is 2 parts by mass or more, preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and 18 parts by mass or less, preferably 16 parts by mass or less, more preferably 12 parts by mass or less, per 100 parts by mass of the resin component.

[0065] When the content of the styrene-based thermoplastic elastomer is equal to or higher than the above lower limit, the powdery flame retardant can be uniformly dispersed.

[0066] On the other hand, if the content of the styrene-based thermoplastic elastomer is less than the above lower limit, the powdery flame retardant cannot be uniformly dispersed.

[0067] When the content of the styrene-based thermoplastic elastomer is equal to or less than the upper limit, the viscosity of the unsaturated polyester resin composition obtained by using the unsaturated polyester resin raw material can be prevented from increasing, and the workability is improved.

[0068] On the other hand, if the content of the styrene-based thermoplastic elastomer exceeds the above upper limit, the viscosity of the unsaturated polyester resin composition obtained by using the unsaturated polyester resin raw material increases, and the workability decreases.

[0069] From the viewpoint of dispersibility, the content of the styrene-based thermoplastic elastomer is, for example, 6 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and 120 parts by mass or less, preferably 90 parts by mass or less, or 75 parts by mass or less, relative to 100 parts by mass of the powdery flame retardant.

[0070] From the viewpoint of dispersibility, the content of the styrene-based thermoplastic elastomer is, for example, 1 part by mass or more, preferably 5 parts by mass or more, and for example, 50 parts by mass or less, preferably 30 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the total amount of the powdery flame retardant and aluminum hydroxide.

[0071] [Other low shrinkage agents] The low profile agent may also contain a low profile agent other than the styrene-based thermoplastic elastomer (hereinafter, sometimes referred to as other low profile agents).

[0072] Other low-profile agents include, for example, polyethylene, polystyrene, crosslinked polystyrene, polyvinyl acetate, polymethyl methacrylate, and saturated polyester resins. Other low-profile agents are preferably polyethylene, polystyrene, and polyvinyl acetate.

[0073] When the low shrinkage agent contains another low shrinkage agent, the content of the other low shrinkage agent is, for example, 20% by mass or more, preferably 30% by mass or more, and for example, 70% by mass or less, preferably 60% by mass or less, relative to the low shrinkage agent. The content of the styrene-based thermoplastic elastomer is, for example, 30% by mass or more, preferably 40% by mass or more, and for example, 80% by mass or less, preferably 70% by mass or less, relative to the low shrinkage agent.

[0074] The low profile agent preferably does not contain other low profile agents and consists of a styrene-based thermoplastic elastomer.

[0075] Alternatively, the low shrinkage agent can be dissolved in the polymerizable monomer to prepare a polymerizable monomer solution of the low shrinkage agent.

[0076] In the polymerizable monomer solution of the low shrinkage agent, the solids concentration of the low shrinkage agent is, for example, 20 mass % or more, and for example, 70 mass % or less, preferably 40 mass % or less.

[0077] The low profile agents can be used alone or in combination of two or more.

[0078] The content of the low shrinkage agent relative to 100 parts by mass of the resin component is, for example, 2 parts by mass or more, preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and for example, 18 parts by mass or less, preferably 16 parts by mass or less, more preferably 12 parts by mass or less.

[0079] The content of the low shrinkage agent relative to 100 parts by mass of the powdery flame retardant is, for example, 6 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and is 120 parts by mass or less, preferably 90 parts by mass or less, more preferably 75 parts by mass or less.

[0080] <Other thermosetting resins> Other thermosetting resins include, for example, vinyl ester resins, brominated vinyl ester resins, and acrylic syrups.

[0081] The content ratio of the other thermosetting resin relative to 100 parts by mass of the resin component is, for example, 1 part by mass or more and, for example, 10 parts by mass or less.

[0082] The resin component preferably does not include other thermosetting resins.

[0083] <Powder flame retardant> The powdered flame retardant imparts flame retardancy to a molded article obtained by using the unsaturated polyester resin raw material, and does not contain aluminum hydroxide, which will be described later.

[0084] The powdered flame retardant is a grain or powder of the flame retardant, specifically a solid having an average particle size of 10 μm or more and 200 μm or less. When the powdered flame retardant is a flame retardant other than expanded graphite, the average particle size can be obtained by creating a particle size distribution curve using a laser diffraction / scattering type particle size distribution measuring device and calculating the particle size equivalent to 50% by mass. When the powdered flame retardant is expanded graphite, the average particle size can be obtained by observing with an optical microscope, measuring the maximum diameter (long diameter) and the particle diameter (short diameter) in the direction perpendicular to the maximum diameter for any 50 powdered flame retardants, and calculating the average value of the long diameter and the short diameter.

[0085] Powdery flame retardants include, for example, halogen-based flame retardants and non-halogen-based flame retardants.

[0086] Examples of halogen-based flame retardants include bromine-based flame retardants, such as hexabromobenzene, tetrabromobisphenol, bromodiphenyl (e.g., tetrabromodiphenyl), and bromodiphenyl ether (e.g., tetrabromodiphenyl ether).

[0087] Examples of non-halogen flame retardants include phosphorus-based flame retardants, inorganic flame retardants, nitrogen-based flame retardants, and expandable graphite.

[0088] Examples of phosphorus-based flame retardants include red phosphorus, phosphoric acid esters (e.g., trimethyl phosphate, triethyl phosphate, tributyl phosphate, tricresyl phosphate), polyphosphates (e.g., aluminum trisdiethylphosphinate), IFR (Intumescent) type intumescent flame retardants containing ammonium polyphosphate, an auxiliary such as pentaerythritol, and a carbon donor such as melamine, and metal phosphinates.Preferably, polyphosphates and metal phosphinates are used as phosphorus-based flame retardants.

[0089] Inorganic flame retardants include, for example, antimony oxide (eg, diantimony trioxide), zinc stannate, zinc borate and preparations thereof.

[0090] Examples of the nitrogen-based flame retardant include an azoalkane compound, a hindered amine compound, and melamine cyanurate. A preferred example of the nitrogen-based flame retardant is melamine cyanurate.

[0091] Expandable graphite is a graphite intercalation compound in which sulfuric acid or the like is inserted between the layers of flake-like natural graphite. Such expandable graphite expands between the layers at temperatures of about 150 to 300°C.

[0092] The powdery flame retardant is preferably a non-halogen flame retardant. More preferably, the powdery flame retardant is a phosphorus-based flame retardant or a nitrogen-based flame retardant. That is, more preferably, the powdery flame retardant includes a phosphorus-based flame retardant and / or a nitrogen-based flame retardant.

[0093] If the powdery flame retardant contains a phosphorus-based flame retardant, the flame retardancy is excellent (more specifically, the strength after combustion in the combustion test described later can be improved).

[0094] If the powdery flame retardant contains a nitrogen-based flame retardant, it has excellent flame retardancy (more specifically, it can suppress discoloration after combustion in a flame resistance test described later).

[0095] More preferably, the powdery flame retardant contains a phosphorus-based flame retardant and a nitrogen-based flame retardant. When the powdery flame retardant contains a phosphorus-based flame retardant and a nitrogen-based flame retardant, the content ratio of the phosphorus-based flame retardant is, for example, 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 45 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, relative to 100 parts by mass of the total amount of the phosphorus-based flame retardant and the nitrogen-based flame retardant. The content ratio of the nitrogen-based flame retardant is, for example, 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 45 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, relative to 100 parts by mass of the total amount of the phosphorus-based flame retardant and the nitrogen-based flame retardant.

[0096] In addition, it is preferable that the powdery flame retardant is substantially free of expandable graphite. The powdery flame retardant being substantially free of expandable graphite means that the content of expandable graphite relative to the powdery flame retardant is, for example, 5% by mass or less, preferably 1% by mass or less, and more preferably 0.1% by mass or less.

[0097] If the powdery flame retardant does not substantially contain expandable graphite, the strength after combustion in the combustion test described below can be improved.

[0098] Powdered flame retardants can be used alone or in combination of two or more types.

[0099] The content ratio of the powdery flame retardant per 100 parts by mass of the resin component is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 18 parts by mass or more, and for example, 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less.

[0100] <Preparation of unsaturated polyester resin raw material> As will be described in detail in the first step, the unsaturated polyester resin raw material is prepared by blending a resin component and a powdered flame retardant.

[0101] The obtained unsaturated polyester resin raw material contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with the powdered flame retardant. Therefore, the dispersibility of the powdered flame retardant can be improved, and the time required to uniformly disperse the powdered flame retardant (described later) can be shortened. As a result, the production efficiency can be improved. Moreover, with such an unsaturated polyester resin raw material, a molded product having excellent flame retardancy and reduced variation in flame retardancy can be produced.

[0102] The unsaturated polyester resin raw material contains a resin component and a powdery flame retardant, but does not contain aluminum hydroxide, which will be described later, and is the subject of commercial trade alone as a raw material for an unsaturated polyester resin composition.

[0103] <Unsaturated polyester resin composition> The unsaturated polyester resin composition contains the unsaturated polyester resin raw material and aluminum hydroxide, that is, the unsaturated polyester resin composition contains a resin component, a powdery flame retardant, and aluminum hydroxide.

[0104] <Aluminum hydroxide> Aluminum hydroxide is blended in order to impart flame retardancy to a molded article obtained using the unsaturated polyester resin composition, as well as to impart transparency and depth to the molded article.

[0105] The content of aluminum hydroxide is, relative to 100 parts by mass of the resin component, for example, 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 110 parts by mass or more, and for example, 300 parts by mass or less, preferably 250 parts by mass or less, more preferably 200 parts by mass or less.

[0106] <Additives> If necessary, additives may be blended into the unsaturated polyester resin composition within the range that does not impair the effects of the present invention.

[0107] Examples of additives include colorants, thickeners, curing agents, polymerization inhibitors, release agents, fillers, separation prevention agents, wetting and dispersing agents, pattern materials, antibacterial agents, hydrophilic agents, photocatalysts, UV absorbers, UV stabilizers, separation prevention agents, silane coupling agents, antistatic agents, thixotropic agents, thixotropic stabilizers, and polymerization accelerators. The additives can be used alone or in combination of two or more.

[0108] [Coloring agent] The colorant is not particularly limited, and examples of the colorant include polyester toners mixed with known pigments such as titanium oxide, carbon black, red iron oxide, and phthalocyanine blue.

[0109] As the colorant, preferably, a polyester toner is used.

[0110] The colorants can be used alone or in combination of two or more kinds.

[0111] The content ratio of the colorant relative to 100 parts by mass of the resin component is, for example, 1 part by mass or more, preferably 5 parts by mass or more, and for example, 20 parts by mass or less.

[0112] [Thickener] The thickener is blended to thicken the unsaturated polyester resin composition to a viscosity suitable for heat compression molding. The thickener is preferably blended before (preferably immediately before) impregnating the unsaturated polyester resin composition into reinforcing fibers (described later).

[0113] Examples of the thickener include alkaline earth metal oxides and alkaline earth metal hydroxides. Examples of the alkaline earth metal oxides include magnesium oxide. Examples of the alkaline earth metal hydroxides include magnesium hydroxide and calcium hydroxide.

[0114] As the thickener, preferably, an alkaline earth metal oxide is used, and more preferably, magnesium oxide is used.

[0115] The thickeners can be used alone or in combination of two or more kinds.

[0116] The content ratio of the thickener relative to 100 parts by mass of the resin component is, for example, 0.5 parts by mass or more, and for example, 10 parts by mass or less, preferably 3 parts by mass or less.

[0117] [Hardening agent] Examples of the curing agent include peroxides. Examples of the peroxides include benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, t-hexylperoxyisopropyl monocarbonate, 1,1-bis(t-butylperoxy)cyclohexane, t-butylperoxy-2-ethylhexanoate, amylperoxy-2-ethylhexanoate, 2-ethylhexylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, t-hexylperoxybenzoate, and t-hexylperoxyacetate. Examples of the curing agent include preferably t-butylperoxyisopropyl carbonate.

[0118] The curing agents can be used alone or in combination of two or more kinds.

[0119] The content ratio of the curing agent relative to 100 parts by mass of the resin component is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and for example, 5 parts by mass or less, preferably 2 parts by mass or less.

[0120] [Polymerization inhibitor] The polymerization inhibitor is added to adjust the pot life and the curing reaction.

[0121] Examples of the polymerization inhibitor include hydroquinone compounds, benzoquinone compounds, catechol compounds, phenol compounds, and N-oxyl compounds.

[0122] As the polymerization inhibitor, preferably, a benzoquinone compound, a hydroquinone compound, and an N-oxyl compound are mentioned.

[0123] An example of the benzoquinone compound is parabenzoquinone.

[0124] Examples of hydroquinone compounds include hydroquinone, methylhydroquinone, and t-butylhydroquinone.

[0125] As the polymerization inhibitor, preferably, a benzoquinone compound is used.

[0126] The content ratio of the polymerization inhibitor is, for example, 0.01 part by mass or more, preferably 0.05 part by mass or more, and for example, 0.5 part by mass or less, preferably 0.2 part by mass or less, and more preferably 0.1 part by mass or less, per 100 parts by mass of the resin component.

[0127] [Release agent] Examples of the release agent include fatty acids, fatty acid metal salts, liquid waxes, fluoropolymers, and silicon-based polymers. Examples of the fatty acids include stearic acid and lauric acid. Examples of the fatty acid metal salts include zinc stearate and calcium stearate.

[0128] The release agent is preferably a fatty acid metal salt, more preferably zinc stearate.

[0129] The release agents can be used alone or in combination of two or more kinds.

[0130] The content ratio of the release agent relative to 100 parts by mass of the resin component is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 10 parts by mass or less.

[0131] [Filling material] Examples of fillers (except aluminum hydroxide) include inorganic fillers. Examples of inorganic fillers include oxides (e.g., alumina, titanium oxide), hydroxides (e.g., magnesium hydroxide), carbonates (e.g., calcium carbonate), sulfates (e.g., barium sulfate), silica (e.g., crystalline silica, fused silica, fumed silica, dry silica (aerosil)), hollow fillers, silicates (e.g., silica sand, diatomaceous earth, glass powder, glass balloons, mica, clay, kaolin, talc), fluorides (e.g., fluorspar), phosphates (e.g., calcium phosphate), metal powders, ceramics, milled fibers, and clay minerals (e.g., smectite).

[0132] The fillers can be used alone or in combination of two or more.

[0133] The filler content is, per 100 parts by mass of the resin component, for example, 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 150 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less.

[0134] [Separation prevention agent] As the separation prevention agent, commercially available products can be used. Specific examples include BYK-W995, BYK-W996, BYK-W9010, BYK-W972, and BYK-9076 (all manufactured by BYK-CHEMIE), Modiper MS10B, S501, SV10A, and SV10B (all manufactured by NOF Corporation).

[0135] The separation inhibitors can be used alone or in combination of two or more kinds.

[0136] The content of the anti-separation agent is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.8 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less, relative to 100 parts by mass of the resin component.

[0137] <Method of producing unsaturated polyester resin composition> The method for producing an unsaturated polyester resin composition includes a first step of blending a resin component and a powdery flame retardant to prepare an unsaturated polyester resin raw material, and a second step of blending aluminum hydroxide with the unsaturated polyester resin raw material to prepare an unsaturated polyester resin composition.

[0138] [1st step] In the first step, a resin component and a powdery flame retardant are mixed to prepare an unsaturated polyester resin raw material.

[0139] In the above preparation, the unsaturated polyester resin (a mixture of the unsaturated polyester and the polymerizable monomer) can be prepared by dissolving the unsaturated polyester in the polymerizable monomer (preferably styrene) in advance and, if necessary, adding the above-mentioned additives.

[0140] In preparing the unsaturated polyester resin, the content ratio of the polymerizable monomer is, for example, 50 parts by mass or more, preferably 60 parts by mass or more, and for example, 80 parts by mass or less, preferably 70 parts by mass or less, relative to 100 parts by mass of the unsaturated polyester.

[0141] In addition, after preparing the unsaturated polyester resin, when this unsaturated polyester resin is mixed with the polymerizable monomer, the shrinkage reducing agent, other thermosetting resins which are blended as necessary, and the powdery flame retardant, a polymerizable monomer can also be blended therein.

[0142] In this way, an unsaturated polyester resin raw material is prepared.

[0143] [Second process] In the second step, an unsaturated polyester resin composition is prepared by blending aluminum hydroxide and, if necessary, the above-mentioned additives with the unsaturated polyester resin raw material.

[0144] In this way, an unsaturated polyester resin composition is prepared.

[0145] The unsaturated polyester resin composition contains the above unsaturated polyester resin raw material. That is, the unsaturated polyester resin composition contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with a powdery flame retardant. Therefore, such an unsaturated polyester resin composition has excellent flame retardancy and can uniformly disperse the powdery flame retardant.

[0146] In the above-mentioned method for producing an unsaturated polyester resin composition, preferably, the unsaturated polyester resin raw material obtained in the first step is divided into small portions, and the second step is carried out for each of the divided unsaturated polyester resin raw materials, thereby improving productivity.

[0147] Furthermore, the unsaturated polyester resin raw material obtained in the first step (and the subdivided unsaturated polyester resin raw material) is usually stored, for example, for 1 day or more and 14 days or less, until the second step is carried out. Although details will be described later, since the unsaturated polyester resin raw material contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent, even when the unsaturated polyester resin raw material obtained in the first step (and the subdivided unsaturated polyester resin raw material) is stored, the dispersibility of the powdery flame retardant can be improved, the time required to uniformly disperse the powdery flame retardant can be shortened, and the production efficiency can be improved.

[0148] 2. Second embodiment In the second embodiment, the unsaturated polyester resin composition is prepared by blending the resin component, the powdery flame retardant, and aluminum hydroxide all at once in the blending ratio described above.

[0149] In the preparation, if necessary, the additives can be blended in the blending ratios described above within the range that does not impair the effects of the present invention. In other words, the unsaturated polyester resin composition contains the additives as necessary.

[0150] The unsaturated polyester resin composition contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with a powdered flame retardant. Therefore, such an unsaturated polyester resin composition has excellent flame retardancy, and furthermore, the powdered flame retardant can be uniformly dispersed. Therefore, in a molded product obtained using this unsaturated polyester resin composition, the flame retardant can be uniformly dispersed, and the variation in flame retardancy can be suppressed.

[0151] <Molding material> A molding material can be prepared by blending reinforcing fibers with the unsaturated polyester resin composition. A molded article can be obtained from such a molding material by a known method.

[0152] The molding material includes an unsaturated polyester resin composition and reinforcing fibers.

[0153] <Reinforced fiber> Examples of reinforcing fibers include inorganic fibers, organic fibers, and natural fibers. Examples of inorganic fibers include glass fibers, carbon fibers, metal fibers, and ceramic fibers. Examples of organic fibers include polyvinyl alcohol-based fibers, polyester-based fibers, polyamide-based fibers, fluororesin-based fibers, and phenol-based fibers. Examples of natural fibers include hemp and kenaf.

[0154] As the reinforcing fiber, preferably, inorganic fiber is used, and more preferably, glass fiber is used.

[0155] Examples of the shape of the reinforcing fibers include cloth (e.g., roving cloth), mat (e.g., chopped strand mat, preformable mat, continuous strand mat, and surfacing mat), strand, roving, nonwoven fabric, and paper.

[0156] The length of the reinforcing fibers is not particularly limited and is, for example, 1.5 mm or more, and from the viewpoint of improving strength, preferably 5 mm or more, more preferably 20 mm or more, and for example, 80 mm or less, preferably 40 mm or less.

[0157] <Preparation of molding material> To prepare the molding material, the unsaturated polyester resin composition is mixed with the reinforcing fibers, specifically, the reinforcing fibers are impregnated with the unsaturated polyester resin composition.

[0158] The method for preparing the unsaturated polyester resin composition may be a known method.Specific examples include SMC (sheet molding compound), TMC (thick molding compound), and BMC (bulk molding compound).Preferably, SMC and TMC are used, and more preferably, SMC is used.

[0159] The content ratio of the reinforcing fibers relative to the molding material is, for example, 15 mass % or more and, for example, 60 mass % or less, preferably 35 mass % or less.

[0160] This gives a molding material (preferably a sheet-like molding material) containing the unsaturated polyester resin composition and the reinforcing fibers.

[0161] The molding material contains the unsaturated polyester resin composition, and therefore, by using such a molding material, it is possible to produce a molded article having excellent flame retardancy and reduced variation in flame retardancy.

[0162] 4. Molded products The molded article includes a cured product of the molding material.

[0163] To harden the molding material, the molding material is first aged to thicken it so that it can be subjected to heat compression molding (described later).

[0164] In the aging, the aging temperature is, for example, 20° C. or more and, for example, 50° C. or less. The aging time is, for example, 8 hours or more and, for example, 120 hours or less.

[0165] This allows the molding material to retain its shape.

[0166] The molding material is then heated and compression molded by a known method.

[0167] The conditions of the heat compression molding are appropriately set according to the purpose and use. In the heat compression molding, the molding temperature is, for example, 100° C. or more, and, for example, 200° C. or less. The molding pressure is, for example, 0.1 MPa or more, preferably 1 MPa or more, more preferably 5 MPa or more, and, for example, 20 MPa or less, preferably 15 MPa or less.

[0168] This causes the molding material to be shaped and hardened, resulting in a molded product.

[0169] The molded article contains a cured product of the molding material, and therefore has excellent flame retardancy and can suppress variation in flame retardancy.

[0170] 4. Effects In the first embodiment, the unsaturated polyester resin composition is prepared by preparing an unsaturated polyester resin raw material and then blending aluminum hydroxide. The unsaturated polyester resin raw material contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with a powdered flame retardant. Therefore, the dispersibility of the powdered flame retardant can be improved, and the time required to uniformly disperse the powdered flame retardant (described later) can be shortened. As a result, the production efficiency can be improved. In addition, according to such an unsaturated polyester resin raw material, a molded product having excellent flame retardancy and reduced variation in flame retardancy can be produced.

[0171] Specifically, in the above-mentioned method for producing an unsaturated polyester resin composition, preferably, the unsaturated polyester resin raw material obtained in the first step is divided into small portions, and the second step is then carried out for each of the divided unsaturated polyester resin raw materials, thereby improving productivity.

[0172] On the other hand, the divided unsaturated polyester resin raw material is temporarily stored until the second step is carried out. In this case, the resin component and the powdery flame retardant may separate, and the powdery flame retardant may become non-uniform in the unsaturated polyester resin raw material. In such a case, it is necessary to stir the unsaturated polyester resin raw material before carrying out the second step to uniformly disperse the powdery flame retardant, but it has been found that if the dispersibility of the powdery flame retardant is low, it takes a long time to uniformly disperse the powdery flame retardant, resulting in a decrease in production efficiency. In addition, when the powdery flame retardant is left non-uniform in the unsaturated polyester resin raw material and the second step is carried out to prepare an unsaturated polyester resin composition, it has been found that the flame retardant becomes non-uniform in the molded product obtained using this unsaturated polyester resin composition, resulting in a variation in flame retardancy.

[0173] In contrast, this unsaturated polyester resin raw material contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with the powdery flame retardant. Therefore, even if the powdery flame retardant becomes non-uniform in the unsaturated polyester resin raw material after temporary storage, the dispersibility of the powdery flame retardant can be improved, and the time required to disperse the powdery flame retardant uniformly can be shortened. This can solve the above-mentioned problem.

[0174] The unsaturated polyester resin composition contains the unsaturated polyester resin raw material, and therefore, according to the unsaturated polyester resin composition, it is possible to produce a molded article having excellent flame retardancy and reduced variation in flame retardancy.

[0175] In the second embodiment, the unsaturated polyester resin composition is prepared by blending a resin component, a powdered flame retardant, and aluminum hydroxide all at once. The unsaturated polyester resin composition contains a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with the powdered flame retardant. Therefore, the composition has excellent flame retardancy, and the powdered flame retardant can be uniformly dispersed. As a result, a molded product with reduced variation in flame retardancy can be manufactured.

[0176] The molding material contains the unsaturated polyester resin composition, and therefore has excellent flame retardancy and can uniformly disperse a powdery flame retardant therein.

[0177] The molded article contains a cured product of the molding material, and therefore has excellent flame retardancy and can uniformly disperse the powdery flame retardant. EXAMPLES

[0178] The present invention will be described in more detail below with reference to examples. However, the following description is an embodiment of the present invention, and the present invention is not limited to these descriptions.

[0179] Specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "not more than" or "less than") or lower limit values ​​(numerical values ​​defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention." In addition, unless otherwise specified in the following description, "parts" and "%" are based on mass.

[0180] <Ingredient details> 2002: Styrene-ethylene-propylene-styrene block copolymer elastomer, styrene content 30%, product name "Septon 2002", manufactured by Kuraray Co., Ltd. H1041: Styrene-ethylene-butylene-styrene block copolymer elastomer, styrene content 30%, product name "Tuftec H1041", manufactured by Asahi Kasei Corporation G1701: Styrene-ethylene-propylene diblock copolymer elastomer, styrene content 37%, product name "KRATON G1701", manufactured by Kraton Elastomers DX410: Styrene-butadiene-styrene branched block copolymer elastomer, product name "KRATON DX410", styrene content 18%, manufactured by Kraton Elastomers 5125: Styrene-isoprene-styrene block copolymer elastomer, styrene content 20%, product name "Hybra 5125", manufactured by Kuraray Co., Ltd. Polyvinyl acetate: Number average molecular weight 30,000 Polystyrene: Number average molecular weight approx. 110,000 Polyethylene: Polyethylene powder with an average particle size of approximately 30 μm Phosphorus-based flame retardant: Aluminum tris(diethylphosphinate), average particle size 30μm Nitrogen-based flame retardant: Melamine cyanurate, average particle size 10μm Expanded graphite: average particle size 75μm Aluminum hydroxide: average particle size 8μm Anti-separation agent: W972, product name "BYK-W972", manufactured by BYK-CHEMIE Anti-separation agent: S501, product name "Modiper S501", manufactured by NOF Corporation

[0181] <Preparation of Unsaturated Polyester Resin> Preparation Example 1 A flask equipped with a thermometer, a nitrogen gas inlet tube, a reflux condenser and a stirrer was used as a reactor. 1500g of propylene glycol, 1860g of maleic anhydride and 0.31g of hydroquinone were charged into the reactor. Next, the above contents were reacted at 210°C while stirring under a nitrogen gas atmosphere. As a result, an unsaturated polyester was obtained. The acid value of this unsaturated polyester was 23.6mgKOH / g. To 100 parts by mass of the obtained unsaturated polyester, 0.015 parts by mass of hydroquinone was added as a polymerization inhibitor, and then 66.7 parts by mass of styrene was added to obtain an unsaturated polyester resin (styrene content 40% by mass).

[0182] <Production of unsaturated polyester resin composition, molding material, and molded article> Examples 1 to 21 and Comparative Examples 1 to 8 Based on the descriptions in Tables 1 and 2, the unsaturated polyester resin, the polymerizable monomer, the shrinkage reducing agent, the powdered flame retardant, the aluminum hydroxide, and the colorant were blended and mixed until uniform, thereby producing an unsaturated polyester resin composition.

[0183] [Production of molding materials] To the unsaturated polyester resin composition, 1.0 part of magnesium oxide was added as a thickener. Then, a known sheet molding compound (SMC) impregnation machine was used to obtain a molding material (sheet molding compound (SMC)). Specifically, the resin composition was applied onto a carrier film using a doctor blade. Then, glass roving was continuously cut into 25 mm pieces, and added so that the glass fiber content was 30 mass %, and an impregnation process was performed to obtain SMC. Next, this molding material was aged at 40°C for 48 hours, and the viscosity was increased until the molding material was in a state where it could be heat-compression molded. In this way, a molding material was produced.

[0184] [Manufacturing of molded products] The molding material was subjected to heat compression molding using a 300 mm x 900 mm flat metal plate to produce a molded product.

[0185] Specifically, molding was performed under the following conditions: mold temperature on both the product surface and the back surface was 140°C, molding pressure was 10 MPa, and retention time in the mold was 300 seconds. After that, the molded product was removed from the mold and immediately sandwiched between iron plates for cooling. In this way, a flat molded product was produced. Three types of molded products were produced: a molded product with a thickness of 4 mm, a molded product with a thickness of 3 mm, and a molded product with a thickness of 2.5 mm.

[0186] <Production of unsaturated polyester resin raw material, unsaturated polyester resin composition, molding material, and molded product> Examples 22 to 36 and Comparative Examples 9 to 16 [1st step] Based on the descriptions in Tables 3 and 4, the unsaturated polyester resin, the polymerizable monomer, the shrinkage reducing agent, and the powdered flame retardant were blended and mixed until no lumps remained, thereby preparing an unsaturated polyester resin raw material.

[0187] [Second process] The unsaturated polyester resin raw material was left to stand for 5 days, and then stirred again until no lumps remained, and then aluminum hydroxide and a colorant were added based on the descriptions in Tables 3 and 4. In this way, an unsaturated polyester resin composition was produced.

[0188] Based on the same procedures as in Example 1, a molding material and a molded product were produced.

[0189] <Evaluation> [Workability during impregnation] The workability during impregnation of the unsaturated polyester resin composition of each Example and Comparative Example was evaluated based on the following criteria. Furthermore, the impregnation state was evaluated by peeling off the carrier film with a cutter knife immediately after the SMC production, and the degree of impregnation of the unsaturated polyester resin composition with the glass fiber was visually evaluated. The results are shown in Tables 1 to 4. {standard} ◯: The impregnation was carried out satisfactorily. The impregnation state was such that the glass fibers were sufficiently wetted with the unsaturated polyester resin composition, and no glass fibers were observed that were not impregnated with the unsaturated polyester resin composition. ◯-: Impregnation was carried out satisfactorily. During impregnation, glass fibers that were not impregnated with the unsaturated polyester resin composition were partially observed. ×: The viscosity of the unsaturated polyester resin composition was high during impregnation, making the work impossible.

[0190] [Flame retardant] (Fire resistance test: discoloration after combustion) Test pieces (150 mm x 150 mm x 4 mm) were cut from the molded products (4 mm thick) of each Example and Comparative Example. Next, using a commercially available cooking burner (Iwatani Corporation's cassette gas cooking burner CJ2), the length of the inner flame of the burner was adjusted to about 40 mm and the temperature of the inner flame tip was adjusted to about 1000°C. Furthermore, the center of the test piece was fixed in a vertical position 40 mm from the tip of the burner. The burner was ignited and the burning state of the molded plate was visually observed for 5 minutes. The above procedure was repeated 5 times for discoloration after burning, and the results were evaluated based on the following criteria. The results are shown in Tables 1 to 4. {standard} ◯: The back surface of the test piece was burnt and discolored 0 to 1 times. △: The back surface of the test piece was burnt and discolored twice. ×: The back surface of the test piece was burned and discolored 3 to 5 times.

[0191] (Combustion test: strength after combustion) Test pieces (85 mm x 25 mm x 2.5 mm) were cut from the molded products (thickness 2.5 mm) of each Example and Comparative Example. The test pieces were then placed in a crucible and treated at 600°C for 1 hour using an electric furnace. Thereafter, the test pieces were cooled to room temperature and removed from the electric furnace, and bending strength was measured in accordance with JIS K7074 (1988). The post-combustion strength was evaluated based on the following criteria. The results are shown in Tables 1 to 4. {standard} ◯: The bending strength exceeded 10N. △: The bending strength was 5N or more and 10N or less. ×: The bending strength was less than 5N.

[0192] (Flame retardancy variation) The molded products (4 mm thick) of each Example and Comparative Example were divided into nine pieces to obtain test pieces. The oxygen index of each test piece was measured in accordance with JIS K7201-2:2021. The variation in flame retardancy was evaluated based on the following criteria. The results are shown in Tables 1 to 4. {standard} ◯: The difference in oxygen index between each test piece was less than 2%. ×: The difference in oxygen index between the test pieces was 2% or more.

[0193] (Compliance with V0-standard (thickness 3mm)) Test pieces (13 mm x 125 mm x 3 mm) were cut from the molded articles (thickness 3 mm) of each Example and Comparative Example, and a combustion test was carried out in accordance with JIS C60695-11-10, Method B. The flame retardancy was evaluated based on the following criteria. The results are shown in Tables 1 to 4. {standard} ○: Combustion components were V-0. ×: Combustion components were other than those mentioned above.

[0194] [Appearance of molded product (uneven gloss)] The molded articles (300 mm×900 mm) of each Example and Comparative Example were visually observed for uneven gloss. The appearance of the molded articles was evaluated based on the following criteria. The results are shown in Tables 1 to 4. {standard} ◯: Gloss unevenness was observed within 0 to 10 mm from the outer periphery of the molded product. ◯-: Gloss unevenness was observed within 10 to 50 mm from the outer periphery of the molded product. ×: Gloss unevenness was observed over a radius of 50 mm or more from the outer periphery of the molded product.

[0195] [Evaluation of the time required to uniformly disperse powdered flame retardants] The unsaturated polyester resin raw material of Examples 22 to 36 and Comparative Examples 9 to 16 (specifically, the unsaturated polyester resin raw material immediately after being obtained in the first step) was left to stand for 5 days and then stirred. The unsaturated polyester resin raw material was observed every 3 minutes for the presence or absence of lumps derived from the powdery flame retardant. The results are shown in Tables 1 and 2. In addition, the time required for the powdery flame retardant to be uniformly dispersed was evaluated based on the following criteria. The results are shown in Tables 3 and 4. {standard} ◯: It took 10 minutes or less to uniformly disperse the powdered flame retardant. △: The time required to uniformly disperse the powdered flame retardant was more than 10 minutes and less than 30 minutes. ×: The time required for uniformly dispersing the powdered flame retardant was more than 30 minutes.

[0196] <Consideration> Examples 1 to 21 contain a styrene-based thermoplastic elastomer as a low shrinkage agent, which is why it is clear that the variation in flame retardancy is small in the molded products.

[0197] On the other hand, Comparative Examples 1 to 4 do not contain a powdery flame retardant or a styrene-based thermoplastic elastomer as a shrinkage reducing agent, and therefore it is understood that there is a large variation in flame retardancy in the molded products.

[0198] In addition, Comparative Examples 5 and 6 contain a styrene-based thermoplastic elastomer as a low-profile agent, but do not contain a powdery flame retardant, and therefore it is found that the flame retardancy (post-combustion discoloration and post-combustion strength) cannot be improved.

[0199] In Examples 22 to 36, a styrene-based thermoplastic elastomer is included as a shrinkage reducing agent together with the powdery flame retardant. This makes it possible to shorten the time required to uniformly disperse the powdery flame retardant when the unsaturated polyester resin raw material obtained in the first step is left to stand for 5 days and then stirred. It is also found that the variation in flame retardancy is small in the molded products obtained using such unsaturated polyester resin raw material.

[0200] On the other hand, Comparative Examples 9 to 12 do not contain a styrene-based thermoplastic elastomer as a shrinkage reducing agent together with the powdery flame retardant. Therefore, when the unsaturated polyester resin raw material obtained in the first step is left to stand for 5 days and then stirred, it is found that the time required to uniformly disperse the powdery flame retardant cannot be shortened. In addition, it is found that the variation in flame retardancy becomes large in the molded products obtained using such unsaturated polyester resin raw material.

[0201] In addition, Comparative Examples 13 and 14 contain a styrene-based thermoplastic elastomer as a low shrinkage agent, but do not contain a powdery flame retardant. Therefore, it is found that the flame retardancy (post-combustion discoloration and post-combustion strength) cannot be improved.

[0202] [Table 1]

[0203] [Table 2]

[0204] [Table 3]

[0205] [Table 4]

Claims

1. A resin component including an unsaturated polyester, a polymerizable monomer, and a shrinkage reducing agent; A powdered flame retardant; and aluminum hydroxide, The low shrinkage agent contains a styrene-based thermoplastic elastomer made of a styrene-conjugated diene copolymer and / or a hydrogenated product thereof, The unsaturated polyester resin composition has a content of the styrene-based thermoplastic elastomer of 2 parts by mass or more and 18 parts by mass or less per 100 parts by mass of the resin component.

2. The unsaturated polyester resin composition according to claim 1 , wherein the powdery flame retardant comprises a phosphorus-based flame retardant and / or a nitrogen-based flame retardant.

3. 2. The unsaturated polyester resin composition according to claim 1, wherein the styrene-based thermoplastic elastomer comprises a hydrogenated product of a styrene-conjugated diene block copolymer.

4. A molding material comprising the unsaturated polyester resin composition according to any one of claims 1 to 3 and reinforcing fibers.

5. A molded article comprising a cured product of the molding material according to claim 4.

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