PROBLEM TO BE SOLVED: To provide a thickening composition which can be thickened by combination with an amino acid-type surfactant and has thickening properties even in a weakly alkaline pH region.SOLUTION: The thickening composition contains an amino acid-type surfactant and a (meth)acrylic acid-based copolymer, where the (meth)acrylic acid-based copolymer is obtained by copolymerization of the following (A), (B) and (C) as monomer components, the molar number ratio of the component (C) to the total molar number of the component (A) and the component (B) is 0.95 to 10 mol%. (A) (meth)acrylic acid (B) (meth)acrylic acid alkyl ester where the alkyl group has a carbon number of 1 to 4 (C) (meth)acrylic acid (polyoxyethylene alkyl ether) ester represented by formula (I): CH2=CRC(O)-(OCH2CH2)n-OCmH2m+1, (in the formula, R represents a hydrogen atom or a methyl group, n represents an integer of 10 to 60, and m represents an integer of 12 to 24.)COPYRIGHT: (C)2014,JPO&INPIT【課題】アミノ酸型界面活性剤と組み合わせることで増粘が可能であり、かつ弱アルカリ性のpH領域においても増粘性を有する増粘性組成物を提供すること。【解決手段】アミノ酸型界面活性剤および(メタ)アクリル酸系共重合体を含み、前記(メタ)アクリル酸系共重合体は、モノマー成分として以下の(A)、(B)及び(C)を共重合して得られ、成分(A)と成分(B)の合計モル数に対する成分(C)のモル数の割合が0.95~10モル%である、増粘性組成物。(A)(メタ)アクリル酸(B)アルキル基の炭素数が1~4である(メタ)アクリル酸アルキルエステル(C)式(I)CH2=CRC(O)-(OCH2CH2)n-OCmH2m+1(I)(式中、Rは水素原子またはメチル基を示し、nは10~60の整数を、mは12~24の整数を示す)で表される(メタ)アクリル酸(ポリオキシエチレンアルキルエーテル)エステル【選択図】なし
