PROBLEM TO BE SOLVED: To provide a novel copolymer which is safe without generating hydrogen has good compatibility with other cosmetic raw materials and, therefore, can improve compounding stability of cosmetics can provide the cosmetics with good water resistance, sebum resistance, gloss, tactile, adhesiveness to hair and skin, and the like can be used for treating fine particles for cosmetics and can be used as a surface preparation agent which can suppress poor dispersion on the skin almost completely.SOLUTION: Provided is a copolymer comprising an unsaturated monomer having a specific carbosiloxane dendrimer structure and (B) an unsaturated monomer having at least one hydrophilic group in a molecule, in which the unsaturated monomer having the carbosiloxane dendrimer structure is present in a range of 35 to 50 mass% of all monomer units. Also provided are a liquid composition, a surface preparation agent and a powder composition each comprising the copolymer, and a cosmetic raw material containing these.COPYRIGHT: (C)2014,JPO&INPIT【課題】水素が発生せず安全であり、他の化粧料原料との親和性がよく、したがって、化粧料の配合安定性を向上することができ、また、化粧料に良好な耐水性、耐皮脂性、光沢、触感、毛髪・皮膚への付着性等を付与し、さらに、幅広い化粧料用粉体の処理に用いることができ、かつ、肌上における分散不良をほぼ完全に抑制しうる表面処理剤として用いる事ができる新規な共重合体を提供する。【解決手段】特定のカルボシロキサンデンドリマー構造を有する不飽和単量体、及び(B)分子中に少なくとも1つの親水性基を有する不飽和単量体を含有してなり、上記のカルボシロキサンデンドリマー構造を有する不飽和単量体が全モノマー単位の35~50質量%の範囲である共重合体、当該共重合体を含む液状組成物、表面処理剤、粉体組成物およびこれらを含有してなる化粧料原料。【選択図】なし
