Kneading apparatus and method for producing semiconductor encapsulating resin composition

A kneading apparatus for kneading a composition containing plural kinds of pulverized materials, said apparatus comprising:

• a casing including:
• a supply port for supplying the composition;
• an elongated cylindrical kneading section for storing the composition supplied through the supply port to knead the composition and having two pairs of screw axis insertion ports respectively provided in both end portions in a longitudinal direction thereof;
• a discharge port for discharging the composition thus kneaded;
• and sealing members respectively provided in the screw axis insertion ports of the kneading section and constituted of an elastic material,
• two screws for kneading the composition stored in the kneading section, the two screws rotatably provided in the casing in parallel with each other, each of the screws including:
• a screw axis having a core portion having a surface and an outer layer having a thickness of 0.3 to 60 mm and provided on a part of the surface of the core portion;
• a screw member provided on the core portion of the screw axis, the screw member provided in the kneading section and having a first screw member and a second screw member oppositely oriented to the first screw member;
• and a kneading member provided on the core portion of the screw axis and between the first screw member and the second screw member, the kneading member provided in the kneading section, and
• two pairs of shaft bearings for respectively supporting the screw axes of the two screws,
• wherein the core portion of the screw axis of each of the two screws is constituted of a metallic material and the outer layer of the screw axis of each of the two screws is constituted of a nonmetallic material,
• wherein the screw axes of the two screws are respectively inserted into the two pairs of screw axis insertion ports and respectively supported by the two pairs of shaft bearings so that the screw axes of the two screws pass through the kneading section in the longitudinal direction of the kneading section,
• wherein the two pairs of shaft bearings respectively support the core portions of the two pairs of screw axes,
• wherein the sealing members are provided so as to seal spaces between the two pairs of screw axis insertion ports and the outer layers of the screw axes of the two screws,
• wherein the kneading section has an inner surface having a thickness of 0.3 to 10 mm and constituted of a nonmetallic material,
• wherein the discharge port serves as a connecting portion connected with a supply port of a degassing device for degassing the composition thus kneaded, and
• wherein the discharge port is provided between the second screw members of the two screws in planar view and opened toward a lower direction perpendicular to the screw axes of the two screws to supply the composition into the degassing device provided below the discharge port.