Strand manufacturing device, pellet manufacturing device, strand manufacturing method, and pellet manufacturing method

A strand manufacturing method comprising:

• a step of supplying resin raw material in a molten state from a flow passage member to a die, the die comprising a plurality of through holes arranged therein;
• and
• a step of molding strands by extruding the resin raw material from the plurality of through holes,
• wherein as the flow passage member, a member that defines a flow passage is used as the flow passage member, the flow passage comprising:
• an outflow port that extends in a first direction in which the plurality of through holes are arranged and reaches to the plurality of through holes;
• an inflow port in which a dimension in the first direction is smaller than a dimension of the outflow port;
• a manifold section that extends from the inflow port in the first direction and a second direction orthogonal to the first direction;
• and
• a slit section that is connected to the manifold section in the second direction and extends from the manifold section to the outflow port,
• wherein a dimension in the second direction of the slit section decreases gradually as a distance from the inflow port in the first direction increases,
• wherein a cross-section of the manifold section that is orthogonal to the first direction decreases gradually as a distance from the inflow port in the first direction increases,
• wherein as the flow passage member, the member that defines the flow passage is used as the flow passage member, the slit section comprising an adjacent slit section that is adjacent to the manifold section, in which the walls of the flow passage of the adjacent slit section that face to a third direction orthogonal to the first direction and the second direction are parallel to each other, in which a dimension T1 in the second direction of the adjacent slit section at a position away from the end portion by a distance x in the first direction of the adjacent slit section toward the inflow port along the first direction has a value that is obtained based on the following equation:
• T1=Te+a·x
• in which a cross-section of the manifold section has a circular shape, and the radius R of the cross-section of the manifold section at a position away from the end portion of the adjacent slit section by the distance x toward the inflow port along the first direction has a value that is obtained based on the following equation:
• R
• =
• [
• (
• N
• +
• 3
• )
• ·
• h
• 1
• N
• +
• 2
• 2
• ⁢
• π
• ⁡
• (
• N
• +
• 2
• )
• ·
• a
• N
• ·
• x
• ]
• 1
• N
• +
• 3
• where Te is a dimension in the second direction of the adjacent slit section at the end portion of the adjacent slit section, a is a change rate of a dimension T1 with respect to the distance x, N is the inverse of a power law index of the resin raw material, and h1 is a dimension in the third direction of the adjacent slit section.

A strand manufacturing device comprising:

• a die comprising a plurality of through holes arranged therein;
• and
• a flow passage member that defines a flow passage for supplying resin raw material in a molten state to the plurality of through holes,
• wherein the flow passage comprises:
• an outflow port that extends in a first direction in which the plurality of through holes are arranged and reaches to the plurality of through holes;
• an inflow port in which a dimension in the first direction is smaller than a dimension of the outflow port;
• a manifold section that extends from the inflow port in the first direction and a second direction orthogonal to the first direction;
• and
• a slit section that is connected to the manifold section in the second direction and extends from the manifold section to the outflow port,
• wherein a dimension in the second direction of the slit section decreases gradually as a distance from the inflow port in the first direction increases,
• wherein a cross-section of the manifold section that is orthogonal to the first direction decreases gradually as a distance from the inflow port in the first direction increases,
• wherein the slit section comprises an adjacent slit section that is adjacent to the manifold section, wherein the walls of the flow passage of the adjacent slit section that face to a third direction orthogonal to the first direction and the second direction are parallel to each other, wherein a dimension T1 in the second direction of the adjacent slit section at a position away from the end portion by a distance x in the first direction of the adjacent slit section toward the inflow port along the first direction has a value that is obtained based on the following equation:
• T1=Te+a·x
• wherein a cross-section of the manifold section has a circular shape, and the radius R of the cross-section of the manifold section at a position away from the end portion of the adjacent slit section by the distance x toward the inflow port along the first direction has a value that is obtained based on the following equation:
• R
• =
• [
• (
• N
• +
• 3
• )
• ·
• h
• 1
• N
• +
• 2
• 2
• ⁢
• ⁢
• π
• ⁡
• (
• N
• +
• 2
• )
• ·
• a
• N
• ·
• x
• ]
• 1
• N
• +
• 3
• where Te is a dimension in the second direction of the adjacent slit section at the end portion of the adjacent slit section, a is a change rate of a dimension T1 with respect to the distance x, N is the inverse of a power law index of the resin raw material, and h1 is a dimension in the third direction of the adjacent slit section.