Abstract: The purpose of the present invention is to provide: a copolymer for cosmetics, which has excellent water repellency and oil repellency even though a polyfluoroalkyl group therein has 6 or less carbon atoms; a surface treatment agent which contains the copolymer for cosmetics; a powder for cosmetics, which is treated with the surface treatment agent and has excellent water repellency and oil repellency; and a cosmetic preparation which contains the powder for cosmetics. A copolymer for cosmetics of the present invention contains: 70-90% by mass of a constituent unit (A) that is derived from a compound represented by formula (a); 2-25% by mass of a constituent unit (B) that is derived from a compound represented by formula (b); 2-25% by mass of a constituent unit (C) that is derived from a compound represented by formula (c); 0.

Abstract: A compound represented by the following formula (a): CH2?CR1—CONJ-CGR2—(CH2)n—COO-Q1-Rf1??(a) is provided. This compound is capable of forming a polymer having an oil repellency equivalent to polymers containing a polyfluoroalkyl group containing at least 8 carbon atoms, although the polyfluoroalkyl group contains up to 6 carbon atoms. In the formula, R1 is hydrogen atom or methyl group, R2 is hydrogen atom or a group represented by —(CH2)m—COO-Q2-Rf2 (r), n and m are independently an integer of 0 to 4, Rf1 and Rf2 are independently a polyfluoroalkyl group or a polyfluoroether group containing 1 to 6 carbon atoms, Q1 and Q2 are independently single bond or a divalent linkage group, J is hydrogen atom or an alkyl group containing 1 to 3 carbon atoms, and G is hydrogen atom or an alkyl group containing 1 to 3 carbon atoms.

Abstract: The purpose of the present invention is to provide: a copolymer for cosmetics, which has excellent water repellency and oil repellency even though a polyfluoroalkyl group therein has 6 or less carbon atoms; a surface treatment agent which contains the copolymer for cosmetics; a powder for cosmetics, which is treated with the surface treatment agent and has excellent water repellency and oil repellency; and a cosmetic preparation which contains the powder for cosmetics. A copolymer for cosmetics of the present invention contains: 70-90% by mass of a constituent unit (A) that is derived from a compound represented by formula (a); 2-25% by mass of a constituent unit (B) that is derived from a compound represented by formula (b); 2-25% by mass of a constituent unit (C) that is derived from a compound represented by formula (c); 0.

Abstract: A compound represented by the following formula (a): CH2?CR1—CONJ-CKR2—(CH2)n—COO-Q1-Rf1??(a) is provided. This compound is capable of forming a polymer having an oil repellency equivalent to polymers containing a polyfluoroalkyl group containing at least 8 carbon atoms, although the polyfluoroalkyl group contains up to 6 carbon atoms. In the formula, R1 is hydrogen atom or methyl group, R2 is hydrogen atom or a group represented by —(CH2)m—COO-Q2-Rf2 (r), n and m are independently an integer of 0 to 4, Rf1 and Rf2 are independently a polyfluoroalkyl group or a polyfluoroether group containing 1 to 6 carbon atoms, Q1 and Q2 are independently single bond or a divalent linkage group, J is hydrogen atom or an alkyl group containing 1 to 3 carbon atoms, K is hydrogen atom or an alkyl group containing 1 to 3 carbon atoms, and j and k are independently single bond or an alkylene group containing 1 to 3 carbon atoms with the proviso that j and k are not simultaneously single bond.