Expandable methyl methacrylate resin particles, pre-expanded particles, expansion molded article, and evaporative pattern

(canceled)

3:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the expandable poly methyl methacrylate particle has a weight average molecular weight measured by gel permeation chromatography (GPC) in terms of polystyrene of from 300,000 to 350,000.

4:

• The expandable poly methyl methacrylate particle according to claim 1, further comprising:
• a solvent having a boiling point of not lower than 50° C. in an amount of from 1.5% to 3.0% by weight relative to a weight of the poly methyl methacrylate particle.

5:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the monomers comprise a bifunctional monomer in an amount of from 0.08% to 0.12% by weight relative to the total weight of the methyl methacrylate and the butyl acrylate in the acrylic monomer.

6:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the process further comprises adding a solvent having a boiling point of not lower than 50° C. after the polymerizing and before impregnating a foaming agent, and an amount of the added solvent is 2.2% to 3.5% by weight relative to a total weight of the methyl methacrylate, the butyl acrylate, and the polyfunctional monomer.

7:

• A poly methyl methacrylate pre-expanded particle, produced by pre-expanding the expandable poly methyl methacrylate particle of claim 1.

8:

• An expanded mold article, produced by molding the poly methyl methacrylate pre-expanded particle of claim 7.

9:

• The expanded mold article according to claim 8, wherein, when a flexural test is performed on the expanded mold article, an amount of displacement at point of rupture is not less than 20 mm.

10:

• A lost form, produced from the expanded mold article of claim 8.

11:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the polyfunctional monomer comprises a bifunctional monomer.

12:

• The expandable poly methyl methacrylate particle according to claim 4, wherein the process further comprises adding 2.2% to 3.5% by weight of the solvent relative to a total weight of the methyl methacrylate, the butyl acrylate, and the polyfunctional monomer, after the polymerizing and before impregnating a foaming agent.

13:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the acrylic monomer comprises 92% to 97% by weight of methyl methacrylate and 3% to 8% by weight of butyl acrylate relative to the total weight of the methyl methacrylate and the butyl acrylate.

14:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the acrylic monomer comprises 93% to 96% by weight of methyl methacrylate and 4% to 7% by weight of butyl acrylate relative to the total weight of the methyl methacrylate and the butyl acrylate.

15:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the expandable poly methyl methacrylate particle has a particle diameter of from 0.5 mm to 1.4 mm.

16:

• The expandable poly methyl methacrylate particle according to claim 1, wherein the acrylic monomer consists of the methyl methacrylate and the butyl acrylate.

17:

• The expandable poly methyl methacrylate particle according to claim 16, wherein the monomers further comprise not more than 10 parts by weight of a second acrylic monomer relative to 100 parts by weight of the acrylic monomer, and the second acrylic monomer comprises at least one selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate.