PROBLEM TO BE SOLVED: To provide a hair tension and stiffness improver that has an excellent hair tension and stiffness improvement effect and can develop the effect for a long period of time and to provide such a hair cosmetic having the tension and stiffness improvement function that is blended with this hair tension and stiffness improver and to provide such a method for improving the tension and stiffness of the hair by using this hair tension and stiffness improver as can develop the effect for a long period of time.SOLUTION: The method uses the hair tension and stiffness improver that includes a lactone derivative expressed by general formula (1), or the hair cosmetic that is blended with this hair tension and stiffness improver (in the formula, n is one or two and R is a 9-22C straight or branched chained, saturated or unsaturated hydrocarbyl group). The effect can be developed for a long period of time by carrying out heat-treatment after applying this hair tension and stiffness improver onto the hair.COPYRIGHT: (C)2013,JPO&INPIT【課題】優れた毛髪のハリコシ改善効果を有し、かつ、その効果を長期間発揮させることができる毛髪のハリコシ改善剤、及び、該ハリコシ改善剤を配合したハリコシ改善作用の毛髪化粧料を提供する。また、該ハリコシ改善剤を用いて、効果を長期間発揮させることができる毛髪のハリコシ改善方法を提供する。【解決手段】下記一般式(1)で表されるラクトン誘導体を含有する毛髪のハリコシ改善剤、又は、該ハリコシ改善剤を配合した毛髪化粧料を用いる。該ハリコシ改善剤を毛髪に塗布した後、熱処理を施すことでその効果を長期間発揮させることが可能である。【化1】(ただし式中、nは1又は2であり、Rは炭素数9~22の直鎖又は分岐鎖の飽和又は不飽和炭化水素基を表す)【選択図】なし
