Sheet forming die and sheet forming method

A sheet forming die comprising:

• a die main body;
• a connection block;
• a resin extruder configured to supply a molten resin;
• a lip gap formed in the die main body and configured to discharge the supplied molten resin to form a sheet-shaped resin-made product;
• a passage provided to flow the supplied molten resin up to the lip gap, the passage branching out into multiple passageways in the connection block in a midstream portion of the passage, downstream ends of the passageways being connected to portions located upstream of the lip gap, respectively, the passage extending from the connection block through the die main body, a second passage in the die main body providing a first molten resin up to the lip gap;
• a plurality of tubular restrictor constituting members, each tubular restrictor constituting member formed as a body separated from the sheet forming die, each restrictor constituting member being provided in a midstream portion of one of the passageways in a connection portion of the die main body and the connection block, wherein a restrictor constituting member is provided in a midstream portion of each of the multiple passageways;
• and
• a temperature controller configured to control a plurality of temperatures, each temperature being a temperature of one of the plurality of restrictor constituting members in order to control a temperature of a plurality of restrictors, each restrictor being a restrictor of one of the plurality of restrictor constituting members, wherein
• each restrictor constituting member is formed with a through-hole configured to receive a flow of the molten resin and configured so as to be mounted integrally with the die main body and the connection block when the connection block is mounted on the die main body;
• each through-hole is configured by two larger diameter parts and a smaller diameter part which is sandwiched between the two larger diameter parts;
• the temperature controller comprises a plurality of ring shaped heaters, each of the heaters being located around a periphery of the smaller diameter part of the through-hole of a corresponding restrictor constituting member;
• each restrictor constituting member is formed as a body separated from the sheet forming die and separated from a portion of the corresponding passageway that is upstream of the corresponding ring shaped heater;
• the temperature controller is configured to control a flow rate of the molten resin by changing a temperature of at least one of the restrictor constituting members, thereby changing a temperature of the molten resin in the at least one restrictor constituting member so that a viscosity of the molten resin is controlled;
• wherein the die main body is configured so that the molten resin in one of the multiple passageways flows together with the first molten resin at one of a pair of edge ends of the first molten resin in a width direction of the first molten resin and the molten resin in another of the multiple passageways flows together with the first molten resin at another of the pair of edge ends of the first molten resin in a width direction of the first molten resin to form the sheet-shaped resin-made product;
• and
• each of the passageways between each of the restrictor constituting members and each of the downstream ends of the passageways connected to portions upstream of the lip gap is located in the die main body.