Patent ID: 6949589

Claim:
A polyurea elastic foamed grinder material for grinding and/or buffing, prepared by subjecting a composition comprising: a main ingredient component (A) including a polyisocyanate (A-1), and a component (B) including an aromatic diamine (B-1), a foaming agent (B-2), a foam stabilizing surfactant (B-3), and a curing catalyst (B-4), to foaming and curing in the presence of grinder granules (C), wherein said aromatic diamine (B-1) is an aromatic diamine oligomer (B-1-1) alone or a mixture of the aromatic diamine oligomer (B-1-1) and an aromatic diamine compound (B-1-2); wherein said aromatic diamine oligomer (B-1-1) is an aromatic diamine oligomer represented by formula (1): wherein R represents a group to give an n-valent polyalkylene polyol, polyalkylene ether polyol or polyalkylene ester polyol each having an average molecular weight of 200 or more; and n represents 2 or 3; and an unsaturated bond or bonds may be contained in the polyalkylene moiety; wherein said aromatic diamine compound (B-1-2) is at least one aromatic diamine compound selected from the group consisting of 4,4′-methylene-bis(2-chloroaniline), 4,4′-methylene-bis(2,3-dichloroaniline), 4,4′-methylene-bis(2,5-dichloroaniline), 4,4′-methylene-bis(3-chloro-2,5-diethylaniline), trimethyleneglycol-bis(4-aminobenzoate), 4-chloro-3,5-diamino-benzoic acid isobutyl ester, 3,5-dimethylthio-2,4-toluenediamine, 3,5-dimethylthio-2,6-toluenediamine, 4,4′-methylene-bis-(methylanthranilate) and 1,2-bis(2-aminophenylthio)ethane; wherein a ratio of the content of said aromatic diamine compound (B-1-2) in the aromatic diamine (B-1) is 50% by mass or less; wherein said main ingredient component (A) and said component (B) are contained in amounts in terms of a molar ratio of isocyanate groups in the isocyanate (A-1) as the main ingredient component (A) to amino groups in the aromatic diamine (B-1) in the component (B) (NCO/NH 2 ), is within 0.8 to 1.5; wherein the foaming agent (B-2) is in an amount more than 0% by mass to 30% by mass or less in the component (B); wherein the foam stabilizing surfactant (B-3) is in an amount more than 0% by mass to 6% by mass or less in the component (B); wherein the curing catalyst (B-4) is in an amount more than 0% by mass to 5% by mass or less in the component (B); and wherein an amount of said grinder granules (C) is 20 to 70% by mass of a total amount of the main ingredient component (A), the grinder granules (C) and the component (B) with the exception of the foaming agent (B-2).