Apparatus and method for manufacturing multiplex interlayer for safety glass

A method for manufacturing a multilayered interlayer for safety glass having a first and a second outermost layers and an inserted layer disposed between the first and the second outermost layers, said method using an apparatus configured for manufacturing the multilayered interlayer for safety glass,

• said apparatus comprising:
• a first extruding machine for delivering a thermoplastic resin composition for the outermost layer formation for forming the first and the second outermost layers;
• a second extruding machine for delivering a thermoplastic resin composition for the inserted layer formation for forming the inserted layer;
• a first delivering hole through which the thermoplastic resin composition for the outermost layer formation is delivered, the first delivering hole being connected to the first extruding machine;
• a second delivering hole through which the thermoplastic resin composition for the inserted layer formation is delivered, the second delivering hole being connected to the second extruding machine;
• outlets for the first and the second outermost layers formation, the outlets for the first and the second outermost layers formation being spaced apart from one another and each having a slit shape corresponding to sectional shapes of the respective first and second layers;
• an outlet for the inserted layer formation for forming the inserted layer, the outlet being disposed between the outlets for the first and the second outermost layers formation;
• a flow path for the outermost layer formation connecting the first delivering hole and the outlets for the first and the second outermost layers formation;
• a guide for a layer disposition, the guide having a flow path for the inserted layer formation that connects the second delivering hole and the outlet for the inserted layer formation;
• a metal mold for extruding the interlayer obtained by lamination of the resin compositions for the first and the second outermost layers formation, and the resin composition for the inserted layer formation that have been delivered, the metal mold being connected to the outlets for the first and the second outermost layers formation and the outlet for the inserted layer formation of the guide for the layer disposition;
• wherein the outlet for the inserted layer formation is provided in the guide for a layer disposition has a shape of a slit extending in a width direction of the interlayer, and has a smaller thickness of the slit with increasing proximity to one end in at least the one end of the shape of a slit,
• said method comprising:
• a process for delivering, from the first extruding machine, the thermoplastic resin composition for the outermost layer formation in a molten state to the first delivering hole of the guide for a layer disposition, and
• for delivering, from the second extruding machine, a thermoplastic resin composition for the inserted layer formation in a molten state to the second delivering hole of the guide for a layer disposition;
• a process for forcing the thermoplastic resin composition for the outermost layer formation in a molten state to arrive in the outlets for the first and the second outermost layers formation through the flow paths for the outermost layers formation in the guide for a layer disposition, and simultaneously for forcing the thermoplastic resin composition for the inserted layer formation in a molten state to arrive to the outlet for the inserted layer formation through the flow path for the inserted layer formation;
• and
• a process of extruding the thermoplastic resin compositions for the first and the second outermost layers formation, and the thermoplastic resin composition for the inserted layer formation as a multilayer film, in a condition for the thermoplastic resin composition for the inserted layer formation delivered from the outlet for the inserted layer formation to be disposed between the thermoplastic resin compositions for the first and the second outermost layers formation delivered from the outlets for the first and the second outermost layers formation in the metal mold for extrusion,
• wherein a first delivering hole provided in the guide for the layer disposition is connected to the first extruding machine for the outermost layer formation, one end of the flow path for formation of the outermost layer is connected to the first delivering hole in the guide for the layer disposition, the flow path for the outermost layer formation is branched to separate first and second branching flow paths midway therebetween, and ends of the first and the second branching flow paths are connected to outlets for the first and the second outermost layer formation, respectively.