Abstract: The present invention provides a foam forming die comprising an inlet 2, a hollow portion 3, and a channel 5, wherein two rotatable bodies 6a and 6b having an outer periphery substantially in the form of a true circle in cross section are disposed at one end portion of the channel 5, and the end of the channel 5 is narrowed by these two rotatable bodies 6a and 6b to form a discharge portion 9. The two rotatable bodies 6a and 6b are rotated in the molten resin discharge direction to control the flow of the molten resin, whereby heat generated due to shearing can be reduced while the pressure inside the die is maintained at a high pressure. Therefore, the temperature of the molten resin can be readily adjusted, and the flow of the molten resin can be rendered uniform. As a result, even foaming agents with low solubility can be used in a large amount, thereby facilitating foaming of various types of hard-to-foam resins.

Abstract: A flat die has an inlet (2) for supplying a molten resin from an extruder to the die therethrough, a hollow portion (3) so formed as to permit the molten resin supplied to spread in widthwise directions, and an outlet (7) for discharging the molten resin therethrough as spread in the widthwise directions, wherein an accommodating portion (12) and rotatable bodies (20,22) are formed between the hollow portion (3) and the outlet (7). Rotatable bodies (20,22) have an outer periphery substantially in the form of a true circle in cross section and substantially the same widthwise length as the outlet (7) and are rotatably disposed within the accommodating portion (12) with an axis thereof extending in the widthwise direction.

Abstract: A method for producing cross-linked polyethylene resin foams which comprises mixing a polyolefin resin, a blowing agent and, optionally, a surface active agent containing hydroxyl groups or an acid amide compound under pressure, said polyolefin resin containing a cross-linkable ethylene polymer having on the side chains thereof silyl groups which effect cross-linking upon contact with water; extruding the mixture into a low pressure zone where the extrudate is allowed to expand; and bringing the expanded extrudate into contact with a silanol condensing catalyst so that the expanded extrudate is cross-linked on contact with water.