Phosphite composition and method for producing the same

A phosphite composition comprising 100 parts by weight of a phosphite represented by the formula (1):

• wherein R1, R2, R4 and R5 independently represent a hydrogen atom, an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 5 to 8 carbon atoms, an alkylcycloalkyl group of 6 to 12 carbon atoms, an aralkyl group of 7 to 12 carbon atoms or a phenyl group,
• R3 represents a hydrogen atom or an alkyl group of 1 to 8 carbon atoms,
• X presents a single bond, a sulfur atom or a —CHR6— group, in which R6 presents a hydrogen atom, an alkyl group of 1 to 8 carbon atoms or a cycloalkyl group of 5 to 8 carbon atoms,
• A represents an alkylene group of 2 to 8 carbon atoms or a *—COR7— group, in which R7 represents a single bond or an alkylene group of 1 to 8 carbon atoms, and the symbol * represents a point being linked with the oxygen atom of the >P—O— group in the formula (1),
• one of Y and Z represents a hydroxyl group, an alkoxy group of 1 to 8 carbon atoms or an aralkyloxy group of 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group of 1 to 8 carbon atoms,
• when Y is a hydroxyl group, one of R4 and R5 represents an alkyl group of 3 to 8 carbon atoms, a cycloalkyl group of 5 to 8 carbon atoms, an alkylcycloalkyl group of 6 to 12 carbon atoms, an aralkyl group of 7 to 12 carbon atoms or a phenyl group, and
• R1, R2 and R3 may be the same or different;
• and 0.5 to 8 parts by weight of an aliphatic hydrocarbon lubricant having a softening point or a melting point of not higher than 115° C., wherein the content of a phosphite represented by the formula (1) in said composition is 30 to 99.5% by weight.