JP6809496B2 - (Meta) Acrylic resin composition, resin molded product, lighting cover and lighting sign - Google Patents

Description

The present invention relates to a (meth) acrylic resin composition, a resin molded product, a lighting lamp cover, and a lighting signboard.

The (meth) acrylic resin containing methyl methacrylate as a main component has excellent transparency and weather resistance, and also has relatively well-balanced performance in resin physical properties such as mechanical strength, thermal properties, and moldability. doing. In particular, (meth) acrylic resin having high flame retardancy is used in many applications such as lighting materials, signboards, decorative members, and building members.
Recently, flame-retardant (meth) acrylic resin may be used for lighting signboards and lighting applications installed indoors and outdoors. In this case, in order to conceal the shape of a light source such as a fluorescent lamp or LED with a lighting signboard or a lighting cover, a (meth) acrylic resin having a milky half color for exhibiting appropriate light diffusivity is desired. There is.

As a technique for imparting a milky half color to exhibit light diffusivity to a flame-retardant (meth) acrylic resin product, for example, Patent Document 1 and Patent Document 2 describe flame-retardant phosphoric acid ester containing a halogenated phosphoric acid ester. A methacrylic resin plate has been proposed, and Patent Document 2 describes that organic or inorganic fine particles are used as a light diffusing agent.
Further, Patent Document 3 and Patent Document 4 propose a flame-retardant methacrylic resin plate containing a methacrylic resin, a phosphorus-based flame retardant, and barium sulfate and titanium oxide as a light diffusing agent.

International Publication No. 2016/063898 Japanese Unexamined Patent Publication No. 2011-046835 Japanese Unexamined Patent Publication No. 5-311026 Japanese Unexamined Patent Publication No. 6-122804

However, in the flame-retardant methacrylic resin plate disclosed in Patent Documents 1 to 4 in which organic or inorganic fine particles are simply added and contained to express a milky half color, the light diffusing agent itself is a methacrylic resin. The flame retardancy was insufficient because it reduced the flame retardancy of the resin. That is, it has been difficult to obtain a (meth) acrylic resin having both flame retardancy and milky half color by the prior art.

An object of the present invention is to provide a (meth) acrylic resin composition having appropriate light diffusivity and high flame retardancy, and a resin molded product obtained by molding the (meth) acrylic resin composition. ..

The present invention has the following aspects.
[1] A (meth) acrylic resin composition containing a (meth) acrylic polymer (P), a phosphorus-based flame retardant (C), and resin particles (F).
The dispersed particle diameter of the resin particles (F) is 0.5 μm or more and 10 μm or less.
The (meth) acrylic polymer (P) is a repeating unit derived from a methacrylic acid ester (M1) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain, and aromatic hydrocarbons. A (meth) acrylic resin composition containing a repeating unit derived from an acrylic acid ester (M2) having a hydrogen group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain.
[2] The (meth) acrylic resin composition according to [1], wherein the (meth) acrylic polymer (P) contains a structural unit derived from a monomer (B) having two or more vinyl groups.
[3] The resin particles (F) are styrene-based fine particles containing 80% by mass or more of the repeating unit derived from the styrene monomer with respect to the total mass of the resin particles (F), [1] or The (meth) acrylic resin composition according to [2].
[4] The (meth) acrylic resin composition according to [3], wherein the styrene-based fine particles have a weight average molecular weight (Mw) of 40,000 or more and 300,000 or less as measured by gel permeation chromatography (GPC).
[5] The (meth) acrylic according to [3] or [4], wherein the styrene-based fine particles have a weight average molecular weight (Mw) of 50,000 or more and 150,000 or less measured by gel permeation chromatography (GPC). Resin composition.
[6] The (meth) acrylic resin composition according to any one of [3] to [5], wherein substantially spherical resin particles are present in the resin particles (F).
[7] The dispersed particle diameter of the resin particles (F) is 0.5 μm or more and 5.0 μm or less.
The (meth) acrylic resin composition according to [6], wherein the dispersed particle diameter of the substantially spherical resin particles is 0.01 μm or more and 0.3 μm or less.
[8] The dispersed particle diameter of the resin particles (F) is 1.0 μm or more and 2.0 μm or less.
The (meth) acrylic resin composition according to [6], wherein the dispersed particle diameter of the substantially spherical resin particles is 0.01 μm or more and 0.1 μm or less.
[9] Of [1] to [8], the amount of the resin particles (F) is 0.5 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer (P). The (meth) acrylic resin composition according to any one of the above.
[10] The (meth) acrylic polymer (P) is based on the total mass of the (meth) acrylic polymer (P).
The repeating unit derived from the methacrylic acid ester (M1) is contained in an amount of 10% by mass or more and 80% by mass or less, and the repeating unit derived from the acrylic acid ester (M2) is contained in an amount of 0.50% by mass or more and 20% by mass or less. The (meth) acrylic resin composition according to any one of [1] to [9].
[11] The (meth) acrylic polymer (P) contains a structural unit derived from the monomer (B) having two or more vinyl groups in an amount of 0.05% by mass or more and 0.40% by mass or less [2]. ] To [9], the (meth) acrylic resin composition according to any one of the items.
[12] The (meth) acrylic resin composition according to any one of [1] to [11], wherein the phosphorus-based flame retardant (C) is a phosphoric acid ester or a phosphonic acid ester.
[13] The (meth) acrylic resin composition according to any one of [1] to [11], wherein the phosphorus-based flame retardant (C) is a halogen-containing phosphoric acid ester or a halogen-containing phosphonic acid ester.
[14] Of [1] to [13], the amount of the phosphorus-based flame retardant (C) is 5.0 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer (P). The (meth) acrylic resin composition according to any one of the above.
[15] A resin molded product obtained by molding the (meth) acrylic resin composition according to any one of [1] to [14].
[16] A resin molded product obtained by molding a (meth) acrylic resin composition containing a (meth) acrylic polymer (P), a phosphorus-based flame retardant (C), and resin particles (F), and is a DIN. A nonflammable resin molded product having a diffusivity of 60% or more and 99% or less measured by 5036 and self-extinguishing in less than 3 minutes when a combustion test is performed by the JIS K6911A method.
[17] It has nonflammability that self-extinguishes in less than 1.5 minutes when a combustion test is performed by the JIS K6911A method, and the dispersed particle size of the resin particles (F) is 1.0 μm or more and 2.0 μm. [16] The resin particles (F) are styrene-based fine particles containing 80% by mass or more of the repeating unit derived from the styrene monomer with respect to the total mass of the resin particles (F). [16] The resin molded body according to.
[18] The resin molded product according to [16] or [17], which has a flame retardancy of V-0 in a vertical combustion test defined by UL94 and has a thickness of 4 mm or more.
[19] An illuminating lamp cover including the resin molded product according to any one of [15] to [18].
[20] A lighting signboard containing the resin molded product according to any one of [15] to [18].

According to the present invention, it is possible to obtain a resin molded product having appropriate light diffusivity and high flame retardancy as a lighting signboard / lighting material, and a (meth) acrylic resin composition for obtaining the resin molded product.

Hereinafter, the present invention will be described in detail.
In the present invention, "(meth) acrylate" means at least one selected from the group consisting of "acrylate" and "methacrylate". "(Meta) acrylic acid" means at least one selected from the group consisting of "acrylic acid" and "methacrylic acid".

Further, "monomer" means an unpolymerized compound, and "repeating unit" means a unit derived from the monomer formed by polymerizing the monomer. The repeating unit may be a unit directly formed by a polymerization reaction, or a part of the unit may be converted into another structure by processing a polymer. The "structural unit" means a unit derived from a monomer used in the production of a (meth) acrylic resin composition. "Mass%" means the content of a predetermined component contained in 100% by mass of the total amount.

<(Meta) acrylic resin composition>
The (meth) acrylic resin composition of the present invention contains a (meth) acrylic polymer (P) described later, a phosphorus-based flame retardant (C) described later, and resin particles (F) described later.

The content of the phosphorus-based flame retardant (C) in the (meth) acrylic resin composition is not particularly limited, but is 5.0 parts by mass or more and 35 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer (P). It can be less than or equal to a mass.

A resin molded product having excellent flame retardancy can be obtained when the content of the phosphorus-based flame retardant (C) is 5.0 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic polymer (P). Further, a resin molded product having excellent heat resistance can be obtained when the content of the phosphorus-based flame retardant (C) is 35 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer (P). The content of the phosphorus-based flame retardant (C) with respect to 100 parts by mass of the (meth) acrylic polymer (P) is preferably 6.0 parts by mass or more, and preferably 23 parts by mass or less.

The content of the resin particles (F) in the (meth) acrylic resin composition is not particularly limited, but is 0.5 parts by mass or more and 4.0 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer (P). By containing the part or less, a resin molded body having an appropriate diffusivity and a milky half-color tone can be obtained.
When the lower limit of the content of the resin particles (F) is 0.5 parts by mass or more, it is preferable because an appropriate diffusivity and a milky half-color tone can be imparted to the resin molded product, and 0.6 parts by mass or more is more preferable. .. Further, when the upper limit of the content of the resin particles (F) is 4.0 parts by mass or less, it is preferable because the flame retardancy of the resin molded product can be maintained, and 3.0 parts by mass or less is more preferable.

<(Meta) acrylic polymer (P)>
The (meth) acrylic resin composition in the present invention contains the following (meth) acrylic polymer (P) as one of the constituent components. By containing the (meth) acrylic polymer (P) as one of the constituent components, a resin molded product having appropriate light diffusivity and high flame retardancy can be obtained by a synergistic effect with other constituent components described later. It becomes possible.

In the present invention, the (meth) acrylic polymer (P) is a repeating unit derived from a methacrylate ester (M1) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain. It contains a repeating unit derived from an acrylic acid ester (M2) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain. Further, it is preferable to contain a structural unit derived from the monomer (B) having two or more vinyl groups.
As used herein, the term "side chain" means an ester moiety.
Details of the methacrylic acid ester (M1), the acrylic acid ester (M2), and the monomer (B) will be described later.

Further, the (meth) acrylic polymer (P) contains 10% by mass or more and 80% by mass or less of the repeating unit derived from the methacrylic acid ester (M1) with respect to the total mass of the (meth) acrylic polymer (P). By containing 0.50% by mass or more and 20% by mass or less of the repeating unit derived from the acrylic acid ester (M2) and 0.05% by mass or more and 0.40% by mass or less of the structural unit derived from the monomer (B). The flame retardancy of the resin molded body can be made more excellent.

The lower limit of the content of the repeating unit derived from the methacrylic acid ester (M1) is that the dispersion stability of the resin particles (F) is good, so that the flame retardancy and light diffusivity of the resin molded product are good, and further, the resin molding is performed. Since the heat resistance of the body is improved, 10% by mass or more is preferable with respect to the total mass of the (meth) acrylic polymer (P). The upper limit of the content is preferably 80% by mass or less because the weather resistance of the resin molded product is good.

The lower limit of the content of the repeating unit derived from the acrylic acid ester (M2) is that the dispersion stability of the resin particles (F) is good, so that the flame retardancy and light diffusivity of the resin molded product are good, and further, the resin molding is performed. Since the heat resistance of the body becomes good, 0.50% by mass or more is preferable, 1.0% by mass or more is more preferable, and 2.0% by mass is more preferable with respect to the total mass of the (meth) acrylic polymer (P). The above is more preferable. The upper limit of the content is preferably 20% by mass or less, more preferably 5.0% by mass or less, still more preferably 4.0% by mass or less, because the heat resistance of the resin molded product becomes good.

The lower limit of the total content of the repeating unit derived from the methacrylic acid ester (M1) and the repeating unit derived from the acrylic acid ester (M2) is not particularly limited, but the dispersion stability of the resin particles (F) is improved. Since the flame retardancy and light diffusivity of the resin molded product are improved and the heat resistance of the resin molded product is further improved, 15% by mass or more is preferable with respect to the total mass of the (meth) acrylic polymer (P). , 20% by mass or more is more preferable. The upper limit of the content is preferably 80% by mass or less because the flame retardancy of the resin molded product can be maintained satisfactorily.

Further, the (meth) acrylic polymer (P) contains a repeating unit derived from methyl methacrylate, so that the transparency and mechanical strength of the resin molded product can be improved. The lower limit of the content of the repeating unit derived from methyl methacrylate in the (meth) acrylic polymer (P) is not particularly limited, but since the transparency and mechanical strength of the resin molded product are improved, ( 20% by mass or more is preferable with respect to the total mass of the meta) acrylic polymer (P). The upper limit of the content is not particularly limited, but is preferably 85% by mass or less because the flame retardancy of the resin molded product can be maintained satisfactorily.

The lower limit of the content of the structural unit derived from the monomer (B) is not particularly limited, but since the flame retardancy of the resin molded product is improved, the total mass of the (meth) acrylic polymer (P) is increased. , 0.05% by mass or more is preferable. The upper limit of the content is not particularly limited, but is preferably 0.40% by mass or less because the impact resistance and mechanical strength of the resin molded product are improved. The specific monomer (B) will be described later.
Examples of the method for producing the (meth) acrylic polymer (P) include a massive polymerization method, a solution polymerization method, an emulsion polymerization method and a suspension polymerization method. Among these, bulk polymerization is preferable from the viewpoint of the production cost of the (meth) acrylic polymer, the environmental load due to the use of a solvent, and the productivity.

<Methacrylic acid ester (M1), acrylic acid ester (M2)>
In the present invention, the (meth) acrylic polymer (P) is a repeating unit derived from a methacrylic acid ester (M1) having an aromatic hydrocarbon or an alicyclic hydrocarbon having 3 to 20 carbon atoms in a side chain, and an aromatic. It contains a repeating unit derived from an acrylic acid ester (M2) having a hydrocarbon group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain. (Hereinafter, if necessary, the methacrylic acid ester (M1) and the acrylic acid ester (M2) are combined and abbreviated as "(meth) acrylic acid ester (M)".)

When heat is applied to the (meth) acrylic acid ester (M), the side chain is detached and converted into a (meth) acrylic acid structural unit. This (meth) acrylic acid structural unit acts on the phosphorus-based flame retardant (C) and interacts with each other, so that the amount of carbide (char) produced when the resin composition burns increases. As a result, the flame retardancy of the resin molded product is improved. On the other hand, the side chain desorbed from the (meth) acrylic acid ester (M) consumes oxygen and the combustion field becomes oxygen-deficient, further enhancing the flame retardancy of the resin composition.
In addition, the addition of the monomer (B) described later further promotes the formation of carbides (chars).
Further, the acrylic acid ester (M2) has an effect of interacting with the phosphorus-based flame retardant (C) described later and synergistically enhances the flame retardant improving effect of the phosphorus-based flame retardant (C). The flame retardancy of the molded product can be improved.

Specific examples of the (meth) acrylic acid ester (M) include cyclohexyl (meth) acrylate, bornyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, and adamantyl (meth) acrylate. Dimethyladamantyl (meth) acrylate, cyclohexyl methacrylate, (meth) norbornylmethyl acrylate, menthyl (meth) acrylate, fentyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth) Dicyclopentenyl acrylate, dicyclopentenyloxyethyl (meth) acrylate, cyclodecyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, benzyl (meth) acrylate , (Meta) acrylic acid esters such as phenoxyethyl (meth) acrylic acid, and derivatives thereof, but are not limited thereto. These can be used alone or in combination of two or more.

In the (meth) acrylic resin composition of the present invention, the methacrylic acid ester (M1) is at least selected from the group consisting of cyclohexyl methacrylate and isobornyl methacrylate from the viewpoint of excellent effects of improving flame retardancy and heat resistance. One kind of monomer can be used.

In the (meth) acrylic resin composition of the present invention, the acrylic acid ester (M2) is excellent in the effect of improving the flame retardancy and weather resistance of the resin molded product, and the effect of improving the dispersion stability of the resin particles (F). From the viewpoint of excellent properties, at least one monomer selected from the group consisting of cyclohexyl acrylate and isobornyl acrylate can be used.

<Monomer (B)>
The monomer (B) is a monomer having two or more vinyl groups, and is one of the constituents of the (meth) acrylic polymer (P). By including the monomer (B) in the (meth) acrylic resin composition, the flame retardancy of the resin molded product can be further improved.

Examples of the monomer (B) include ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, and 1,6-hexanediol di. Examples thereof include alkanediol di (meth) acrylates such as (meth) acrylates, neopentyl glycol di (meth) acrylates, and tricyclodecanedimethanol di (meth) acrylates. These can be used alone or in combination of two or more.

Among the above-mentioned monomers (B), the monomer (B) having 10 to 14 carbon atoms has good handleability as a raw material, and therefore has good workability when producing a (meth) acrylic resin composition. Is improved.

Further, if the monomer (B) is at least one monomer selected from the group consisting of ethylene glycol di (meth) acrylate and neopentyl glycol di (meth) acrylate, the handleability of the raw material is excellent. In addition to this, it is preferable because the flame retardancy of the resin molded product can be made more excellent.

<Copolymerizable monomer>
In the present invention, if necessary, a monomer copolymerizable with methyl methacrylate or (meth) acrylic acid ester (M) is contained in the (meth) acrylic polymer (P) as a (meth) acrylic polymer. It can be copolymerized in the range of 0 to 10% by mass with respect to the total mass of (P).

Examples of the monomer copolymerizable with (meth) acrylic acid ester (M) include ethyl (meth) acrylic acid, isopropyl (meth) acrylic acid, t-butyl (meth) acrylic acid, and (meth) acrylic acid. Unsaturated carboxylic acids such as i-butyl, n-butyl (meth) acrylic acid, (meth) acrylic acid, maleic acid, and itaconic acid, acid anhydrides such as maleic anhydride and itaconic anhydride, N-phenylmaleimide, N. -Maleimide derivatives such as cyclohexyl maleimide, vinyl esters such as vinyl acetate and vinyl benzoate, vinyl chloride, vinylidene chloride and their derivatives, nitrogen-containing monomers such as methacrylamide and acrylonitrile, glycidyl acrylate (meth) acrylate and the like. Examples thereof include an epoxy group-containing monomer and an aromatic vinyl compound such as styrene and α-methylstyrene.

<Phosphorus flame retardant (C)>
In the present invention, the (meth) acrylic resin composition contains a phosphorus-based flame retardant (C) as one of the constituent components in order to enhance the flame retardancy of the resin molded product. A flame retardant synergistic effect can be obtained by using a phosphorus-based flame retardant (C) having a flame retardancy improving effect in combination with the (meth) acrylic acid ester (M), and the flame retardancy of the resin molded product can be improved.

Examples of the phosphorus-based flame retardant (C) include a phosphoric acid ester-based compound (hereinafter, abbreviated as “phosphoric acid ester”) and a phosphonic acid ester-based compound (hereinafter, abbreviated as “phosphonic acid ester”). Can be done.
Examples of the phosphorus-based flame retardant (C) include a halogen-free phosphoric acid ester-based compound (hereinafter, abbreviated as “halogen-free phosphoric acid ester”) and a halogen-containing phosphoric acid ester-based compound (hereinafter, “halogen-containing phosphoric acid”). (Abbreviated as "ester"), halogen-free phosphonic acid ester-based compound (hereinafter, abbreviated as "halogen-free phosphonic acid ester"), halogen-containing phosphonic acid ester-based compound (hereinafter, "halogen-containing phosphonic acid ester". It is abbreviated as.). Specific examples thereof include, but are not limited to, the following compounds. These compounds can be used alone or in combination of two or more.

Examples of the phosphoric acid ester include halogen-free phosphate esters such as trimethyl phosphate, triethyl phosphate, and triphenyl phosphate; tris (chloroethyl) phosphate, tris (chloropropyl) phosphate, and tris (dichloropropyl) phos. Halogen-containing phosphates such as fate, tris (dibromopropyl) phosphate, bis (2,3-dibromopropyl) -2,3-dichloropropyl phosphate, bis (chloropropyl) octyl phosphate; and halogen-containing alkyl poly Examples thereof include, but are not limited to, polyphosphates containing halogen atoms such as phosphate (halogen-containing condensed phosphoric acid esters) and derivative compounds thereof. These can be used alone or in combination of two or more.

Specific examples of the halogen-free phosphoric acid ester include "JAMP-2", "JAMP-4", "JAMP-8", "JAMP-12", and "JP-501" manufactured by Johoku Chemical Co., Ltd. , "JP-502", "JP-504", "JP-504A", "JP-506-H", "JP-508", "JP-512", "JP-513", "JP-518-" "O", "JP-524-R", "LB-58", "DBP", "TMP", "TEP", "TPP", "TCP", "TXP" manufactured by Daihachi Chemical Industry Co., Ltd. , "CDP", "PX-110", "# 41", "CR-733S", "CR-741", "PX-200", "DAIGUARD-400 / 580/610", etc. Can be done.

Specific examples of the halogen-containing phosphoric acid ester include "TMCPP", "CRP", "CR-900", "DAIGUARD-540", "CR-504L", and "CR" manufactured by Daihachi Chemical Industry Co., Ltd. Commercially available products such as "-570" can be used.

Examples of the phosphonic acid ester include, but are limited to, dimethylvinylphosphonate, diethylvinylphosphonate, diphenylvinylphosphonate, diphenylvinylphosphine oxide and the like, derivative compounds thereof, and condensates thereof. It's not a thing. These can be used alone or in combination of two or more.

Specifically, as the phosphonate ester, commercially available products such as "V series" manufactured by Katayama Chemical Industry Co., Ltd. and "Non Nen 73" manufactured by Maruhishi Yuka Kogyo Co., Ltd. can be used.

<Resin particles (F)>
The resin molded product of the present invention is produced using a (meth) acrylic resin composition containing resin particles (F). By using the resin particles (F) as a light diffusing agent, the resin molded product can exhibit an appropriate light diffusing property while maintaining high flame retardancy.
Examples of the structure of the resin particles (F) include a graft polymer.
Examples of the form of the resin particles (F) include powders, beads, pellets and liquids.

In the present invention, it is preferable to control the dispersed particle diameter of the resin particles (F) in the (meth) acrylic resin composition to a range of 0.5 μm or more and 10 μm or less. When the lower limit of the dispersed particle size is 0.5 μm or more, it is possible to impart appropriate light diffusivity to the resin molded product, and since it is not necessary to excessively contain the resin particles (F), high-luminance diffused light can be obtained. Therefore, it is preferable, and 1.0 μm or more is more preferable. When the upper limit of the dispersed particle size is 10 μm or less, the resin particles (F) are uniformly dispersed in the (meth) acrylic resin composition, so that the flame retardancy of the resin molded product can be maintained well, and the brightness of the diffused light can be improved. It is preferable because it can be maintained well and the surface appearance of the resin molded product is good, more preferably 5.0 μm or less, and further preferably 2.0 μm or less.
The "dispersed particle size" refers to a small piece cut out from a (meth) acrylic resin composition or a sheet-shaped resin molded body using an ultramicrotome or the like, and passes near the center of the resin particle using a transmission electron microscope. For 30 arbitrary resin particles or agglomerated particles observed in the cross section, the maximum particle size of the primary particle size of the resin particles or the secondary particle size of the agglomerated particles was measured and averaged. The agglomerated particles refer to secondary particles formed by contacting resin particles (primary particles).

As a method for controlling the dispersed particle size, the content of the repeating unit derived from the styrene monomer constituting the styrene resin particles, the type of the comonomer to be copolymerized with the styrene monomer, and the (meth) acrylic polymer ( The type and content of the repeating unit derived from the (meth) acrylic acid ester (M) contained in P), the polymerization conditions when polymerizing the styrene resin particles, and before being contained in the (meth) acrylic resin composition. A known method can be adopted, such as adjusting the particle size of the styrene-based resin particles.

As a method for producing powders and beads of styrene-based resin particles, a method in which a monomer mixture dispersed in water is polymerized using a dispersion stabilizer, and then vacuum-dried after washing and dehydration treatment to obtain powder. Can be mentioned. Further, as a method for producing pellets of styrene-based resin particles, for example, a method of obtaining pellets by extruding the powder obtained by the above method, or a method of bulk polymerization of a monomer mixture in a reactor has not been performed. Examples thereof include a method of obtaining pellets by extruding while separating and removing the monomer of the reaction. As the polymerization format, known polymerization formats such as radical polymerization, suspension polymerization, and anionic polymerization can be used.

The type of the resin particles (F) is not particularly limited, but a known thermoplastic resin can be used. Known thermoplastic resins include, for example, (meth) acrylic resin particles, styrene resin particles, MS resin (methacryl-styrene copolymer resin) particles, silicone resin particles, polyethylene resin particles, and polypropylene resin. Examples thereof include particles, polyester-based resin particles, and polyamide-based resin particles. These can be used alone or in combination of two or more. Among them, the styrene resin particles or the (meth) acrylic resin particles are easy to adjust the refractive index and have good dispersion stability in the (meth) acrylic resin composition, so that it is easy to control the light diffusivity of the resin molded body. , It is preferable because the weather resistance is good.
Since the (meth) acrylic resin particles have high affinity for the repeating unit derived from the methacrylic acid ester (M1) and the repeating unit derived from the acrylic acid ester (M2) in the (meth) acrylic polymer (P), The dispersion stability in the (meth) acrylic resin composition becomes better. The light diffusing effect and flame retardancy of the resin molded product can be improved.
As the styrene-based resin particles, the resin particles containing 80% by mass or more of the repeating unit derived from the styrene monomer with respect to the total mass of the resin particles (F) increase the refractive index of the resin fine particles. , Preferable from the viewpoint of improving the light diffusion effect of the resin molded body.
As for the refractive index of the styrene resin particles to be added, it is preferable that the difference in the refractive index from the (meth) acrylic polymer (P) is in the range of 0.01 or more and 3.0 or less. When the difference in refractive index is 0.01 or more, the resin molded product can exhibit appropriate light diffusivity, which is preferable, and 0.03 or more is more preferable. When the difference in refractive index is 2.5 or less, the resin molded product is preferable because it can maintain the light diffusivity over an appropriate optical path length from the light source, and more preferably 2.0 or less.
In the present specification, the "refractive index" is based on ISO 13468 and can be measured using an Abbe refractometer using a sodium D line at 23 ° C.

As the styrene-based fine particles, it is preferable to use a polymer having a weight average molecular weight (Mw) of 40,000 or more and 300,000 or less as measured by gel permeation chromatography (GPC). The lower limit of the weight average molecular weight is preferably 40,000 or more from the viewpoint that the dispersed particle diameter of the resin particles (F) in the (meth) acrylic resin composition is 0.5 μm or more, and 50,000 from the viewpoint of 1.0 μm or more. The above is more preferable. On the other hand, the upper limit of the weight average molecular weight is preferably 300,000 or less from the viewpoint that the dispersed particle size of the resin particles (F) in the (meth) acrylic resin composition is 10 μm or less, and the dispersed particle size is 5.0 μm or less. To 150,000 or less is more preferable.

The resin molded product of the present invention can take a form in which substantially spherical resin particles are present in the resin particles (F). "Approximately spherical" refers to a shape without corners. The presence of substantially spherical resin particles in the resin particles (F) tends to improve the flame retardancy of the resin molded product.
It should be noted that the presence of substantially spherical resin particles in the resin particles (F) means that the resin particles (F) selected unspecifiedly are observed in a cross section near the center of the resin particles using a transmission electron microscope. This refers to a state in which 5 to 20 substantially spherical resin particles are present in a 1 μm × 1 μm field of view in the resin particles (F).

When the dispersed particle size of the resin particles (F) is 0.5 μm or more and 5.0 μm or less, the dispersed particle size of the substantially spherical resin particles can be in the range of 0.01 μm or more and 0.3 μm or less. Such a form can be obtained by using styrene-based fine particles having a weight average molecular weight (Mw) of 40,000 or more and 300,000 or less.
When the dispersed particle size of the resin particles (F) is 1.0 μm or more and 2.0 μm or less, the dispersed particle size of the substantially spherical resin particles can be in the range of 0.01 μm or more and 0.1 μm or less. Such a form can be obtained by using styrene-based fine particles having a weight average molecular weight (Mw) of 50,000 or more and 150,000 or less.
The morphology and the dispersed particle diameter of the substantially spherical resin particles can be observed by using the same method as the method for measuring the dispersed particle diameter of the resin particles (F) described above.

As the resin particles (F) described above, a commercially available product may be used, or the resin particles (F) may be produced from a monomer by a known method.
Commercially available products of (meth) acrylic resin particles include, for example, Metablen series (W-341) manufactured by Mitsubishi Rayon Co., Ltd., Chemisnow MR-2G, MS-300X manufactured by Soken Kagaku Co., Ltd., and Asahi Kasei Chemicals Co., Ltd. ), Such as the Delpet series (SRB215).
Examples of commercially available styrene-based resin particles include particles derived from styrene-based monomers such as styrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, and α-methylstyrene. These styrene resin particles may or may not be crosslinked. Specifically, the SX series (SX-130H, SX-200H, SX-350H) manufactured by Soken Chemical Co., Ltd., the SBX series (SBX-6, SBX-8, SBX-12) manufactured by Sekisui Plastics Co., Ltd., etc. Commercially available products can be mentioned.
When commercially available resin particles (F) are used, the average particle size of the resin particles (F) is not particularly limited, but it may be selected according to the purpose for which the resin molded product is used. For example, as commercially available resin particles, resin particles having an average particle size of about 0.5 to 20 μm can be obtained. When the lower limit of the average particle size is 0.5 μm or more, the dispersibility of the resin particles (F) in the resin molded product is good, and a resin molded product having an appropriate diffusivity and a milky half-color tone can be obtained. Is preferable. When the upper limit of the average particle size is 20 μm or less, it is preferable from the viewpoint of flame retardancy of the resin molded product, brightness when the resin molded product is used as a light diffusing plate, surface smoothness, and the like. The average particle size is a measurement of the resin particles (F) alone before being contained in the (meth) acrylic resin composition, and can be measured as a weight average diameter by the Coulter counter method.

<Resin molded product>
The resin molded product of the present invention is obtained by molding a (meth) acrylic resin composition containing the above-mentioned (meth) acrylic polymer (P), a phosphorus-based flame retardant (C), and resin particles (F). ..
The flame retardancy of a resin molded product generally has a so-called trade-off relationship with the diffusivity measured by DIN 5036, and the flame retardancy tends to decrease as the diffusivity increases. That is, the resin molded product of the present invention is a resin molded product having a remarkable property of achieving both flame retardancy and diffusivity, which are contradictory properties.

In the present invention, as the diffusivity of the resin molded product, the value of the diffusivity measured according to DIN 5036 can be used. The diffusion rate of the resin molded product of the present invention can be in the range of 60% or more and 99% or less. When used as a lighting cover for fluorescent lamps, LEDs, etc. in lighting signboard applications and lighting applications, it is preferable that the lower limit of the diffusivity of the resin molded body is 60% or more from the viewpoint of hiding the shape of the light source. Further, when the upper limit of the diffusion rate is 99% or less, it is preferable from the viewpoint of ensuring sufficient brightness. The value of the diffusivity of the resin molded product can be controlled to a desired value by adjusting the composition of the (meth) acrylic resin composition described later, the type and content of the light diffusing agent, and the like.
The above-mentioned resin molded product can be produced, for example, by molding a (meth) acrylic resin composition satisfying the requirements of the present invention by a known method.

Further, the resin molded product of the present invention has a nonflammability that self-extinguishes in less than 3 minutes in the JIS K 6911 flame resistance method A test. If the resin molded product has a flame retardancy that self-extinguishes in less than 3 minutes in the above test, it is preferable from the viewpoint of safety because it can prevent the spread of fire and other types of fire in the event of a fire. In addition to the use of, it is also suitable for use in lighting signs such as gas stations. Such a resin molded product can be produced, for example, by molding by a known method using a (meth) acrylic resin composition satisfying the requirements of the present invention.

Further, in the resin molded product of the present invention, the dispersed particle diameter of the resin particles (F) is 1.0 μm or more and 2.0 μm or less, and the repeating unit derived from the styrene monomer is used as the resin particles (F). When styrene-based fine particles containing 80% by mass or more with respect to the total mass are used, it can have nonflammability that self-extinguishes in less than 1.5 minutes when a combustion test is performed by the JIS K6911A method.

Further, the resin molded product of the present invention can have a flame retardancy of V-0 in the vertical combustion test defined by UL94 by setting the thickness of the resin molded product to 4 mm or more. If the resin molded body has a flame retardancy of UL94 / V-0 in the above test, it is preferable from the viewpoint of safety because the resin molded body does not continue to burn even if it comes into contact with a flame in the event of a fire, such as a fluorescent lamp or an LED. In addition to being used for lighting signs such as lighting covers and gas stations, it is also suitable for use in lighting signs inside moving bodies such as railroad vehicles and automobiles. In such a resin molded product, for example, in a (meth) acrylic resin composition satisfying the requirements of the present invention, the amount of the phosphorus-based flame retardant (C) is based on 100 parts by mass of the (meth) acrylic polymer (P). Is 15 parts by mass or more, and the content of the resin fine particles (F) is 3.0 parts by mass or less.
In this specification, the thickness can be measured with a thickness gauge.

The shape of the resin molded product is not limited, but as one embodiment, a plate-shaped resin plate can be used. The thickness of the resin plate is not particularly limited, but can be 1 mm or more and 30 mm or less. When the lower limit of the resin plate thickness is 1 mm or more, the strength of the resin molded product can be made sufficient. When the upper limit of the resin plate thickness is 30 mm or less, the moldability of the resin molded product is good.
<Lighting cover, lighting signboard>
The illumination lamp cover of the present invention includes the resin molded product of the present invention described above.
The lighting signboard of the present invention includes the resin molded product of the present invention described above.
Here, "including the resin molded product of the present invention" means that the (meth) acrylic resin composition or the resin molded product of the present invention is included as the "main component material" of the lighting lamp cover or the lighting signboard. To do. Here, the "main component material" indicates the material when the lighting cover or the lighting signboard is made of a single material, and when it is made of a plurality of materials, among the constituent materials. Indicates the material with the highest mass fraction.

<Manufacturing method of resin molded product>
The method for producing the resin molded product of the present invention is not particularly limited, and for example, it can be produced by using a known casting polymerization method such as a cell casting method or a continuous casting method described later. In the casting polymerization method, the (meth) acrylic resin composition is placed in a mold consisting of two inorganic glass plates or metal plates (SUS plates) arranged oppositely at predetermined intervals by sealing the periphery with a gasket such as a resin tube. This is a method of forming a (meth) acrylic resin composition by injecting and polymerizing a polymerizable raw material for obtaining the resin, and peeling the obtained (meth) acrylic resin composition from a mold to obtain a resin molded product.
The mold for casting polymerization is not particularly limited, and a known mold can be used. Examples of the mold for obtaining a plate-shaped resin molded product include a mold for cell casting and a mold for continuous casting.
As a mold for cell casting, for example, two plate-like bodies such as an inorganic glass plate, a chrome-plated metal plate, and a stainless steel plate are arranged to face each other at predetermined intervals, and a gasket is arranged at the edge thereof to form a plate-like body. And the one in which a sealed space is formed by a gasket.
As a mold for continuous casting, for example, a sealed space is formed by facing surfaces of a pair of endless belts traveling in the same direction at the same speed and gaskets traveling at the same speed as the endless belts on both sides of the endless belt. The ones that were made to be mentioned.
As the polymerization method when the cast polymerization method is used, for example, a known method can be used in the same manner as the above-mentioned method for producing an acrylic polymer.
The distance between the voids of the mold is appropriately adjusted so as to obtain a resin plate having a desired thickness, but is generally 1 to 30 mm.

Hereinafter, the present invention will be described with reference to examples. In the following, "part" means "part by mass".

The abbreviations of the compounds used in Examples and Comparative Examples are as follows.
MMA: Methyl methacrylate ・ IBXMA: Isobornyl methacrylate ・ IBXA: Isobornyl acrylate ・ TBMA: t-butyl methacrylate ・ BA: n-butyl methacrylate ・ EDMA: Ethylene glycol dimethacrylate ・ CR-570: Halogen-containing condensed phosphorus Acid ester (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.)
-St-based particles: Commercially available styrene-based resin particles (GPC weight average molecular weight (Mw): 91,000, styrene unit content: 100% by mass)
-St pellets: Commercially available styrene pellets (GPC weight average molecular weight (Mw): 200,000, styrene unit content: 100% by mass)
-Crosslinked particles A: Commercially available styrene resin particles (trade name: KSR-3A, manufactured by Soken Kagaku Co., Ltd., content of styrene unit: 100% by mass)
-Crosslinked particles B: Commercially available styrene-based resin particles (trade name: SBX-12, manufactured by Sekisui Plastics Co., Ltd., styrene unit content: 100% by mass)
-Crosslinked particles C: Commercially available styrene resin particles (trade name: SX-130H, manufactured by Soken Chemical Co., Ltd.)
-Silica particles: Commercially available silica particles (trade name: Seahoster P100, manufactured by Nippon Catalyst Co., Ltd., content of styrene unit: 0% by mass)

The evaluation in Examples and Comparative Examples was carried out by the following method.
(1) Dispersed particle size of the resin particles (F) The dispersed particle size of the resin particles (F) is the average particle size of the resin particles contained in the (meth) acrylic resin composition or the resin molded body. After cutting the (meth) acrylic resin composition or cutting the sheet-shaped resin molded product in the direction perpendicular to the main plane, small pieces were cut out using an ultramicrotome (manufactured by Leica, trade name: EM-ULTRACUTUCT). .. Next, the small pieces obtained by using a transmission electron microscope (JEM-1011, manufactured by JEOL Ltd., magnification 10,000 times) are observed, and in a cross section passing near the center of the resin particles, any resin particles or Thirty agglomerated particles were selected, the maximum particle size of the primary particle size of the resin particles or the secondary particle size of the agglomerated particles was measured, and the average value was calculated. It was calculated using image analysis software in order to judge from the image.
(2) Dispersed particle size of substantially spherical resin particles The dispersed particle size of substantially spherical resin particles is the average particle size of the resin particles contained in the resin particles (F). When the cross section of the unspecified resin particles (F) passing near the center of the resin particles is observed by using a transmission electron microscope in the same manner as the dispersed particle diameter of the resin particles (F) described above. In addition, 30 arbitrary substantially spherical resin particles observed in a field of 1 μm × 1 μm in the resin particles (F) were selected, the maximum particle size of the resin particles was measured, and the average value was calculated. It was calculated using image analysis software in order to judge from the image.

(3) Diffusibility The following evaluation was performed using a plate-shaped resin molded product having a thickness of 3 mm. The resin molded body was installed at a distance of 1.5 m from the lit 45 W fluorescent lamp, and it was evaluated whether or not the lamp shape of the fluorescent lamp could be confirmed through the resin molded body.
◯: The lamp shape of the fluorescent lamp cannot be confirmed.
Δ: The lamp shape of the fluorescent lamp can be confirmed very slightly.
X: The lamp shape of the fluorescent lamp can be clearly confirmed.

(4) Diffusion rate The following evaluation was performed using a plate-shaped resin molded product having a thickness of 3 mm. Using a variable-angle photometer (manufactured by Murakami Color Technology Laboratory Co., Ltd., trade name: GP-200), when light is incident on the sample at 0 °, it is 5 °, 20 °, 70 ° with respect to the sample. The brightness value of the transmitted light at an angle was measured, and the diffusion rate was calculated.

(5) Nonflammable (JIS)
As an index of flame retardancy, a test piece of a resin molded product was prepared in accordance with the flame resistance test A method of JIS K 6911-1979, and the nonflammability of the test piece was evaluated. The time required for self-extinguishing of the test piece (self-extinguishing time) was measured, and the judgment was made using the following criteria.
◯: The self-extinguishing time of the test piece is less than 3 minutes.
X: The self-extinguishing time of the test piece is 3 minutes or more, or the test piece does not self-extinguish.

(6) Flame retardant (UL94)
As an index of flame retardancy, a test piece (length 127 mm × width 12.7 mm) of a resin molded product was prepared in accordance with the UL94 vertical combustion test method, and the flame retardancy of the test piece was evaluated. Further, the judgment was made using the criteria shown in Table 1.

[Example 1]
(1) Production of syrup A mixture of 68.0 parts of MMA, 20.0 parts of IBXMA, 3.0 parts of IBXA, 8.0 parts of TBMA and 1.0 part of BA is placed in a reactor (polymerization pot) equipped with a cooling tube, a thermometer and a stirrer. After feeding and bubbling with nitrogen gas while stirring, heating was started. When the internal temperature of the reactor reached 60 ° C., 0.1 part of 2,2'-azobis- (2,4-dimethylvaleronitrile) was added as a radical polymerization initiator, and the internal temperature of the reactor was further increased. After heating to 100 ° C., the mixture was held for 13 minutes. Then, the reactor was cooled to room temperature to obtain syrup. The content of the polymer in the syrup was 30% by mass and the content of the monomer composition was 70% by mass with respect to the total mass of the syrup.

(2) Cast polymerization 100 parts of the above syrup, 0.15 part of EDMA as the monomer (B), 10.7 parts of CR-570 as the phosphorus flame retardant (C), and St-based particles as the resin particles (F). 1.7 parts were added to obtain a polymerizable composition. Next, the polymerizable composition was poured into a space having a gap spacing of 4.1 mm provided by arranging a vinyl chloride resin gasket at the end of the SUS plate between the two opposing SUS plates, and the mixture was poured at 82 ° C. for 30 minutes. Then, the mixture was heated at 130 ° C. for 30 minutes to cure the polymerizable composition to obtain a (meth) acrylic resin composition. The composition of the (meth) acrylic resin composition is shown in Table 3. Next, after cooling the (meth) acrylic resin composition together with the SUS plate, the SUS plate was removed to obtain a plate-shaped resin molded product having a thickness of 3 mm. The content of the phosphorus-based flame retardant (C) in the resin molded product was 10.7 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer (P). Table 4 shows the evaluation results of the resin molded product. In Table 4, "-" means that the measurement was not performed.

[Examples 2 to 5]
A (meth) acrylic resin composition and a resin molded product were produced in the same manner as in Example 1 except that the composition of the polymerizable composition was changed as shown in Table 2. The composition of the obtained (meth) acrylic resin composition is shown in Table 3. Table 4 shows the evaluation results of the obtained resin molded product.

[Examples 6 to 7]
The (meth) acrylic resin composition was changed in the same manner as in Example 1 except that the composition of the polymerizable composition was changed as shown in Table 2 and the plate thickness of the resin molded product was changed as shown in Table 4. , And a resin molded product were manufactured. The composition of the obtained (meth) acrylic resin composition is shown in Table 3. Table 4 shows the evaluation results of the obtained resin molded product.

[Comparative Examples 1 to 3]
A (meth) acrylic resin composition and a resin molded product were obtained in the same manner as in Example 1 except that the composition of the polymerizable composition was as shown in Table 2. The composition of the obtained (meth) acrylic resin composition is shown in Table 3. Table 4 shows the evaluation results of the obtained resin molded product.

[Example 8, Comparative Example 4]
A (meth) acrylic resin composition and a resin molded product were obtained in the same manner as in Example 1 except that the composition of the polymerizable composition was as shown in Table 2. The composition of the obtained (meth) acrylic resin composition is shown in Table 3. Table 4 shows the evaluation results of the obtained resin molded product.

The resin molded product obtained in Comparative Example 1 is flame-retardant (JIS) because the (meth) acrylic polymer (P) does not contain repeating units derived from methacrylic acid ester (M1) and acrylic acid ester (M2). Was defective.
Since the resin molded product obtained in Comparative Example 2 did not contain the resin particles (F), the light diffusivity was poor.
The resin molded product obtained in Comparative Example 3 had poor flame retardancy and light diffusivity because the dispersed particle diameter of the resin particles (F) exceeded 10 μm.
Since the resin molded product obtained in Comparative Example 4 used silica particles (stem particles) instead of the resin particles (F), the flame retardancy was poor.

INDUSTRIAL APPLICABILITY According to the present invention, a milky semi-colored resin molded product having appropriate flame retardancy, light diffusivity, and coloring characteristics as a lighting signboard or a lighting lamp cover, and a resin composition for obtaining the resin molded product are obtained. be able to.

Claims (22)

A (meth) acrylic resin composition containing a (meth) acrylic polymer (P), a phosphorus-based flame retardant (C), and resin particles (F).
The dispersed particle diameter of the resin particles (F) is 0.5 μm or more and 10 μm or less.
The (meth) acrylic polymer (P) is a repeating unit derived from a methacrylic acid ester (M1) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain, and aromatic hydrocarbons. It contains a repeating unit derived from an acrylic acid ester (M2) having a hydrogen group or an alicyclic hydrocarbon group having 3 to 20 carbon atoms in a side chain .
A (meth) acrylic resin composition in which the resin particles (F) are styrene-based fine particles containing 80% by mass or more of a repeating unit derived from a styrene monomer with respect to the total mass of the resin particles (F) . The (meth) acrylic resin composition according to claim 1, wherein the (meth) acrylic polymer (P) contains a structural unit derived from a monomer (B) having two or more vinyl groups. The (meth) acrylic resin composition according to claim 1 , wherein the styrene-based fine particles have a weight average molecular weight (Mw) of 40,000 or more and 300,000 or less as measured by gel permeation chromatography (GPC). The (meth) acrylic resin composition according to claim 1 or 2 , wherein the styrene-based fine particles have a weight average molecular weight (Mw) of 50,000 or more and 150,000 or less as measured by gel permeation chromatography (GPC). The (meth) acrylic resin composition according to any one of claims 1 to 4 , wherein substantially spherical resin particles are present in the resin particles (F). The dispersed particle size of the resin particles (F) is 0.5 μm or more and 5.0 μm or less.
The (meth) acrylic resin composition according to claim 5 , wherein the dispersed particle diameter of the substantially spherical resin particles is 0.01 μm or more and 0.3 μm or less. The dispersed particle diameter of the resin particles (F) is 1.0 μm or more and 2.0 μm or less.
The (meth) acrylic resin composition according to claim 5 , wherein the dispersed particle diameter of the substantially spherical resin particles is 0.01 μm or more and 0.1 μm or less. The item according to any one of claims 1 to 7 , wherein the amount of the resin particles (F) is 0.5 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer (P). The (meth) acrylic resin composition described. The (meth) acrylic polymer (P) is based on the total mass of the (meth) acrylic polymer (P).
The repeating unit derived from the methacrylic acid ester (M1) is contained in an amount of 10% by mass or more and 80% by mass or less, and the repeating unit derived from the acrylic acid ester (M2) is contained in an amount of 0.50% by mass or more and 20% by mass or less. The (meth) acrylic resin composition according to any one of claims 1 to 8 . The (meth) acrylic polymer (P) is, according to claim 2-8, containing a monomer having two or more vinyl groups (B) more than 0.05 wt% structural units derived from 0.40 wt% or less The (meth) acrylic resin composition according to any one of the above. The (meth) acrylic resin composition according to any one of claims 1 to 10 , wherein the phosphorus-based flame retardant (C) is a phosphoric acid ester or a phosphonic acid ester. The (meth) acrylic resin composition according to any one of claims 1 to 10 , wherein the phosphorus-based flame retardant (C) is a halogen-containing phosphoric acid ester or a halogen-containing phosphonic acid ester. The item according to any one of claims 1 to 12 , wherein the amount of the phosphorus-based flame retardant (C) is 5.0 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer (P). The (meth) acrylic resin composition described. A resin molded product obtained by molding the (meth) acrylic resin composition according to any one of claims 1 to 13 . A resin molded product obtained by molding a (meth) acrylic resin composition containing a (meth) acrylic polymer (P), a phosphorus-based flame retardant (C), and resin particles (F).
The resin particles (F) are styrene-based fine particles containing 80% by mass or more of the repeating unit derived from the styrene monomer with respect to the total mass of the resin particles (F).
The diffusion rate measured by DIN 5036 is 60% or more and 99% or less, and JIS
A nonflammable resin molded product that self-extinguishes in less than 3 minutes when a combustion test is performed by the K6911A method. It has non-flammability that self-extinguishes in less than 1.5 minutes when a combustion test is performed by the JIS K6911A method, and
Dispersion particle size of 1.0μm or more 2.0μm or less, the resin molded article according to claim 15 of the resin particles (F). It has a flame retardancy of V-0 in the vertical combustion test specified by UL94 and has a flame retardancy of V-0.
The resin molded product according to claim 15 or 16 , wherein the thickness of the resin molded product is 4 mm or more. The resin molded product according to any one of claims 15 to 17, wherein the styrene-based fine particles have a weight average molecular weight (Mw) of 40,000 or more and 300,000 or less measured by gel permeation chromatography (GPC). The resin molded product according to any one of claims 15 to 18, wherein substantially spherical resin particles are present in the resin particles (F). The dispersed particle size of the resin particles (F) is 0.5 μm or more and 5.0 μm or less.
The resin molded product according to claim 19, wherein the dispersed particle diameter of the substantially spherical resin particles is 0.01 μm or more and 0.3 μm or less. A lighting cover comprising the resin molded product according to any one of claims 14 to 20 . A lighting signboard comprising the resin molded product according to any one of claims 14 to 20 .