Method for manufacturing pneumatic tire and pneumatic tire
In a method for manufacturing a pneumatic tire, a laminated body is formed of a film containing a thermoplastic resin or elastomer, and rubber sheets laminated on surfaces of the film. A winding starting end of the inner rubber sheet is on a side opposite to a winding direction of the laminated body with respect to an end of the film; an end of the outer rubber sheet at the winding starting end is at the same position as the end of the film or is positioned on a side of the winding direction of the laminated body with respect to the end of the film. An outer surface of the outer rubber sheet at the winding starting end and an inner surface of the inner rubber sheet of a winding finishing end are brought into contact by overlapping and bonding the winding starting end and the winding finishing end.
1. A method for manufacturing a pneumatic tire, comprising: a splice process of winding a laminated body around an outer circumference of a tire forming drum and bonding a winding starting end and a winding finishing end of the laminated body with each other, the laminated body having a trilayer structure comprising:
a film containing, as a main component, a thermoplastic resin or a thermoplastic elastomer composition containing a mixture of a thermoplastic resin and an elastomer; and
a pair of rubber sheets laminated on both surfaces of the film,
wherein, on the tire forming drum, the pair of rubber sheets comprises an inner rubber sheet being a layer on a side of the tire forming drum with respect to the film and an outer rubber sheet being a layer arranged on a side opposite to the tire forming drum with respect to the film,
an end of the inner rubber sheet at the winding starting end is positioned on a side opposite to a winding direction of the laminated body with respect to an end of the film, and an end of the outer rubber sheet at the winding starting end is positioned on a side of the winding direction of the laminated body with respect to the end of the film,
an outer surface of the outer rubber sheet at the winding starting end and an inner surface of the inner rubber sheet at the winding finishing end are brought into contact with each other by overlapping and bonding the winding starting end and the winding finishing end of the laminated body with each other,
the film has a thickness of from 0.03 mm to 0.15 mm,
each of the pair of rubber sheets has a thickness of from 0.2 mm to 1.0 mm,
an angle formed by a straight line, which connects the end of the inner rubber sheet at the winding starting end to the end of the outer rubber sheet at the winding starting end, with respect to a direction perpendicular to an outer surface of the tire forming drum is from 20° to 55°,
an angle formed by the end of the inner rubber sheet is parallel to the direction perpendicular to the outer surface of the tire forming drum,
an angle formed by the end of the outer rubber sheet is parallel to the direction perpendicular to the outer surface of the tire forming drum, and
the end of the film is positioned between than the end of the outer rubber sheet and the inner rubber sheet in the winding direction.
2. The method for manufacturing a pneumatic tire according to claim 1 , wherein an end of the outer rubber sheet at the winding finishing end is positioned on the side of the winding direction of the laminated body with respect to the end of the film, and an end of the inner rubber sheet at the winding finishing end is at a same position as the end of the film or is positioned on the side opposite to the winding direction of the laminated body with respect to the end of the film.
3. The method for manufacturing a pneumatic tire according to claim 1 , wherein a length of a portion in which the outer surface of the outer rubber sheet at the winding starting end and the inner surface of the inner rubber sheet at the winding finishing end are brought into contact with each other is from 5 mm to 20 mm.
4. The method for manufacturing a pneumatic tire according to claim 1 , wherein the film contains nylon.
5. The method for manufacturing a pneumatic tire according to claim 1 , further comprising a process of compression bonding the winding starting end and the winding finishing end overlapping with each other between the splice process and a vulcanization process.
6. The method for manufacturing a pneumatic tire according to claim 1 , wherein the laminated body is an unvulcanized innerliner layer.