PROBLEM TO BE SOLVED: To solve such a problem that, when being inserted into a syringe, an inactive film cannot be tightly fixed to a syringe inner wall and, in a case where a medical solution with high permeability is sealed therein, having a possibility of causing leakage.SOLUTION: A laminate gasket according to the present invention includes: a circumferential surface 17 coming into contact with an inner peripheral surface 16 of a syringe 11 a liquid contact surface concatenated with one edge side of the circumferential surface a bottom surface 20 formed at the other edge side of the circumferential surface and a screw hole 21 recessedly provided from a center of the bottom surface 20 toward a body inside and being engageable with a tip end 18 of a plunger 12. The screw hole 21 includes a female screw with a plurality of threads threaded in the inner peripheral surface from an entrance of the screw hole 21 to a deepest portion 22 of the screw hole. When F1 is a diameter of the female screw of at least one thread located at the deepest portion 22 of the screw hole, F2 is a diameter of the female threads other than that, and D1 is the diameter of a male screw for at least one thread located at a foremost of the plunger 12, the following relationship F2>D1>F1 is satisfied.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2017,JPO&INPIT【課題】シリンジに挿入された際に、不活性フィルムはシリンジ内壁に密着しきれず、浸透性の高い薬液が封入された際には漏れが生じる可能性があった。【解決手段】この発明のラミネートガスケットは、シリンジ11の内周面16に接する円周面部17と、円周面部の一端縁側に連接された接液面と、円周面部の他端縁側に形成された底面20と、底面20の中央から本体内へ凹設された、プランジャ12の先端部18が螺合され得る螺子穴21とを有し、螺子穴21には、螺子穴21の入口から螺子穴の最深部22に向かって、その内周面に複数周期分の雌螺子が切られている。螺子穴の最深部22に位置する少なくとも1周期分の雌螺子の径をF1、それ以外の雌螺子の径をF2、プランジャ12の最先端の少なくとも1周期分の雄螺子の径をD1としたとき、F2>D1>F1の関係を満たす。【選択図】図2
