Method of manufacturing pneumatic tire
View Patent ↗The present technology provides a method of manufacturing a pneumatic tire. The method of manufacturing a pneumatic tire uses a laminated sheet having a predetermined length and an inner liner layer formed from the laminated sheet through a step of cure-molding the tire with end portions of the laminated sheet lap-spliced. In the method, when at least the sheet made of thermoplastic resin or a thermoplastic resin composition obtained by blending the thermoplastic resin and the elastomer is cut into the predetermined length, the cutting is performed by using an edge tool having a non-sharp edge under a temperature condition not lower than 60° C. and not higher than a melting point of the thermoplastic resin.
1. A method of manufacturing a pneumatic tire which uses a laminated sheet having a predetermined length and is obtained by laminating a thermoplastic sheet, made of a thermoplastic resin composition obtained by blending a thermoplastic resin and an elastomer, to a rubber sheet which is cured and adhered to the thermoplastic resin composition in the tire, and in which an inner liner layer of the tire is formed from the laminated sheet through a step of cure-molding the tire with end portions of the laminated sheet lap-spliced, the method characterized in that when the thermoplastic sheet is cut into the predetermined length, the cutting is performed by using an edge tool having a non-sharp edge under a temperature condition not lower than 60° C. and lower than a melting point of the thermoplastic resin, wherein the edge tool having the non-sharp edge has:
a first tapered portion which extends from a non-tapered portion of the edge tool, the non-tapered portion having a thickness of from 1 to 3 mm and linear tapered walls of the first tapered portion defining an angle Θof from 10° to 25° between one another and tapering to a second tapered portion;
the second tapered portion, which extends from the first tapered portion to a rounded tip of the edge tool, with linear tapered walls of the second tapered portion defining an angle α of from 70° to 130° between one another and ending at the rounded tip; and
the rounded tip attached to the second tapered portion and possessing a radius of curvature of from 0.02 to 0.3 mm;
wherein the laminated sheet is cut by bringing the edge tool into contact with a surface of the thermoplastic sheet linearly from a direction perpendicular to the surface of the thermoplastic sheet so that a shaped cut surface is created in the thermoplastic sheet such that a thickness T (μm) of the shaped cut surface has a relationship satisfying 0.1t≦T≦0.8t at a position inward in a tire circumferential direction by a length of (t×⅓) from a tip of the thermoplastic sheet, where t is an average thickness (μm) of the thermoplastic sheet (not including a portion deformed due to cutting).
2. The method of manufacturing a pneumatic tire according to claim 1 , wherein the thickness T has a relationship satisfying 0.2t≦T≦0.6t.
3. The method of manufacturing a pneumatic tire according to claim 1 , wherein the end portions of the laminated sheet are lap-spliced with an overlap of from 7 to 20 mm.
4. The method of manufacturing a pneumatic tire according to claim 1 , wherein the end portions of the laminated sheet are lap-spliced with an overlap of from 8 to 15 mm.