A copolymer of at least, an unsaturated monomer having a carbosiloxane dendrimer structure represented by the following formula: wherein Z is a divalent organic group; p is 1; each of R 1 and R 2 independently represents an alkyl group, an aryl group or an aralkyl group, having 1 to 10 carbon atoms; and L 1 is a silylalkyl group, in the case of i=1, represented by the following formula: wherein Z and p are the same as defined above; R 1 and R 2 are the same as defined above; i is an integer ranging from 1 to 10, which specifies the total number of generations of said silylalkyl group; L i+1 is a group selected from the group consisting of a hydrogen atom, alkyl, aryl and aralkyl groups, having 1 to 10 carbon atoms and said silylalkyl group, with the proviso that in the case of i = c, in which c is an integer ranging from 1 to 10, and specifies generation of said silylalkyl group, L i+1 is a hydrogen atom, or an alkyl, aryl or aralkyl group, having 1 to 10 carbon atoms; and in the case of i < c, L i+1 is said silylalkyl group; and a i is an integer ranging from 0 to 3, and an unsaturated monomer having a long-chain alkyl group with 14 to 22 carbon atoms, with the proviso that {(weight of component)/(weight of all the monomers)} ≥ {(weight of component)/(weight of all the monomers)}. an unsaturated monomer having a carbosiloxane dendrimer structure represented by the following formula: wherein Z is a divalent organic group; p is 1; each of R 1 and R 2 independently represents an alkyl group, an aryl group or an aralkyl group, having 1 to 10 carbon atoms; and L 1 is a silylalkyl group, in the case of i=1, represented by the following formula: wherein Z and p are the same as defined above; R 1 and R 2 are the same as defined above; i is an integer ranging from 1 to 10, which specifies the total number of generations of said silylalkyl group; L i+1 is a group selected from the group consisting of a hydrogen atom, alkyl, aryl and aralkyl groups, having 1 to 10 carbon atoms and said silylalkyl group, with the proviso that in the case of i = c, in which c is an integer ranging from 1 to 10, and specifies generation of said silylalkyl group, L i+1 is a hydrogen atom, or an alkyl, aryl or aralkyl group, having 1 to 10 carbon atoms; and in the case of i < c, L i+1 is said silylalkyl group; and a i is an integer ranging from 0 to 3, and Z is a divalent organic group; p is 1; each of R 1 and R 2 independently represents an alkyl group, an aryl group or an aralkyl group, having 1 to 10 carbon atoms; and L 1 is a silylalkyl group, in the case of i=1, represented by the following formula: wherein Z and p are the same as defined above; R 1 and R 2 are the same as defined above; i is an integer ranging from 1 to 10, which specifies the total number of generations of said silylalkyl group; L i+1 is a group selected from the group consisting of a hydrogen atom, alkyl, aryl and aralkyl groups, having 1 to 10 carbon atoms and said silylalkyl group, with the proviso that in the case of i = c, in which c is an integer ranging from 1 to 10, and specifies generation of said silylalkyl group, L i+1 is a hydrogen atom, or an alkyl, aryl or aralkyl group, having 1 to 10 carbon atoms; and in the case of i < c, L i+1 is said silylalkyl group; and a i is an integer ranging from 0 to 3, and Z and p are the same as defined above; R 1 and R 2 are the same as defined above; i is an integer ranging from 1 to 10, which specifies the total number of generations of said silylalkyl group; L i+1 is a group selected from the group consisting of a hydrogen atom, alkyl, aryl and aralkyl groups, having 1 to 10 carbon atoms and said silylalkyl group, with the proviso that in the case of i = c, in which c is an integer ranging from 1 to 10, and specifies generation of said silylalkyl group, L i+1 is a hydrogen atom, or an alkyl, aryl or aralkyl group, having 1 to 10 carbon atoms; and in the case of i < c, L i+1 is said silylalkyl group; and a i is an integer ranging from 0 to 3, and an unsaturated monomer having a long-chain alkyl group with 14 to 22 carbon atoms,