(Meth)acrylic resin composition and resin molded article

1. A (meth)acrylic resin composition comprising a (meth)acrylic polymer (P) and a phosphorus atom-containing compound (C), wherein

the (meth)acrylic polymer (P) comprises

(1) a repeating unit derived from methyl methacrylate at 19.95% by mass or more and 84.95% by mass or less,

(2) repeating units derived from a (meth)acrylic acid ester (M), including

(2-1) a repeating unit derived from a methacrylic acid ester (M1) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain at 10% by mass or more and 79.5% by mass or less and

(2-2) a repeating unit derived from an acrylic acid ester (M2) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain at 0.50% by mass or more and 20% by mass or less, and

(3) a repeating unit derived from a monomer (B) having two or more vinyl groups at 0.05% by mass or more and 0.40% by mass or less;

a sum of the repeating unit derived from a methacrylic acid ester (M1) and the repeating unit derived from an acrylic acid ester (M2) is 15.0% by mass or more and 80.0% by mass or less; and

an amount of the phosphorus atom-containing compound (C) with respect to 100 parts by mass of the (meth)acrylic polymer (P) is 5.0 parts by mass or more and 35 parts by mass or less.

2. The (meth)acrylic resin composition according to claim 1 , wherein an amount of the repeating unit derived from methyl methacrylate in the (meth)acrylic polymer (P) is 19.95% by mass or more and 79.1% by mass or less and an amount of the repeating units derived from a (meth)acrylic acid ester (M) is 20.5% by mass or more and 80.0% by mass or less.

3. The (meth)acrylic resin composition according to claim 1 , wherein the (meth)acrylic polymer (P) is a polymer which comprises

(1) the repeating unit derived from a methacrylic acid ester (M1) at 10% by mass or more and 79.5% by mass or less and

(2) the repeating unit derived from acrylic acid ester (M2) at 0.50% by mass or more and 20.0% by mass or less as the repeating units derived from a (meth)acrylic acid ester (M) and has

a sum of the repeating unit derived from a methacrylic acid ester (M1) and the repeating unit derived from an acrylic acid ester (M2) of 20.5% by mass or more and 80.0% by mass or less.

4. The (meth)acrylic resin composition according to claim 1 , wherein the methacrylic acid ester (M1) is at least one kind selected from the group consisting of isobornyl methacrylate and cyclohexyl methacrylate.

5. The (meth)acrylic resin composition according to claim 1 , wherein the acrylic acid ester (M2) is at least one kind selected from the group consisting of isobornyl acrylate and cyclohexyl acrylate.

6. The (meth)acrylic resin composition according to claim 1 , comprising a phosphorus atom-containing compound (C) at Y parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer (P), wherein

Y is represented by the following formulas:

5.00≤ Y≤ 13.6 in a case of 15.0≤ X≤ 41.4, and

5.00≤ Y≤ 0.0700 X+ 10.7 in a case of 41.4< X≤ 80.0,

wherein, X (unit: parts by mass) is a content of a repeating unit which is derived from a (meth)acrylic acid ester having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain and contained in the (meth)acrylic polymer (P) with respect to 100 parts by mass of the (meth)acrylic polymer (P).

7. The (meth)acrylic resin composition according to claim 1 , comprising a phosphorus atom-containing compound (C) at Y parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer (P), wherein

Y is represented by the following formulas:

7.6< Y≤ 35.0 in a case of 15.0≤ X≤ 41.4, and

−0.07 X+ 16.5< Y≤ 35.0 in a case of 41.4< X≤ 80.0,

wherein, X (unit: parts by mass) is a content of a repeating unit which is derived from a (meth)acrylic acid ester having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain and contained in the (meth)acrylic polymer (P) with respect to 100 parts by mass of the (meth)acrylic polymer (P).

8. The (meth)acrylic resin composition according to claim 1 , comprising a phosphorus atom-containing compound (C) at Y parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer (P), wherein

the (meth)acrylic polymer (P) is a polymer comprising

(1) the repeating unit derived from methyl methacrylate at 19.95% by mass or more and 58.6% by mass or less,

(2) the repeating unit derived from a (meth)acrylic acid ester (M) having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain at 41% by mass or more and 80% by mass or less, and

(3) the repeating unit derived from a monomer (B) having two or more vinyl groups at 0.05% by mass or more and 0.40% by mass or less, and

Y is represented by the following formula:

−0.07 X+ 16.5≤ Y≤− 0.07 X+ 10.7,

wherein, X (unit: parts by mass) is a content of a repeating unit which is derived from a (meth)acrylic acid ester having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having from 3 to 20 carbon atoms in a side chain and contained in the (meth)acrylic polymer (P) with respect to 100 parts by mass of the (meth)acrylic polymer (P).

9. The (meth)acrylic resin composition according to claim 1 , wherein the monomer (B) is a compound having from 10 to 13 carbon atoms.

10. The (meth)acrylic resin composition according to claim 1 , wherein the monomer (B) is at least one kind selected from the group consisting of ethylene glycol di(meth)acrylate and neopentyl glycol di(meth)acrylate.

11. The (meth)acrylic resin composition according to claim 1 , wherein the phosphorus atom-containing compound (C) contains at least one kind selected from the group consisting of a phosphoric acid ester and a phosphonic acid ester.