There is provided a polyolefin resin foam sheet having a plurality of cells which is formed by foaming a polyolefin resin, wherein, in the polyolefin resin foam sheet, the average cell sizes and the maximum cell sizes in the MD direction and the TD direction are each a predetermined value, and a ratio [TD strength at break/MD average cell size] and a ratio [MD strength at break/TD average cell size] are both 80 kPa/μm or more.

One object of the present invention is to provide a polyolefin resin foam sheet suitable as a sealing substrate having both flexibility and heat resistance despite its thinness, and an adhesive tape in which the polyolefin resin foam sheet is used. In order to achieve this, the polyolefin resin foam includes a thermoplastic elastomer, wherein the endothermic peaks measured by a differential scanning calorimeter (DSC) occur in the range of at least 110° C. or more and 143° C. or less and at 153° C. or more, and the thermoplastic elastomer resin is contained at a ratio of 30% by mass or more and 60% by mass or less in 100% by mass of the polyolefin resin.

A preparation method of a high-rate foamed polylactic acid (PLA) sheet includes first-stage extrusion, second-stage extrusion, and foamed sheet extrusion. The method requires the following raw materials in parts by mass: 88 to 94 parts of PLA, 1 to 2 parts of a nucleating agent, 2 to 5 parts of a foaming agent, and 2 to 5 parts of an additive. The new method effectively solves the problems of low foaming rate, low strength, and the like in the industrial production using carbon dioxide, and a prepared PLA sheet with high foaming rate and excellent surface performance can be used in the fields of food packaging, disposable fully-degradable lunch boxes, and the like.

There is provided a polyolefin resin foam sheet formed by foaming a polyolefin resin, wherein the expansion ratio of the foam sheet is 1.5 to 20 cm.sup.3/g, the average cell sizes in the MD direction and the TD direction of the foam sheet are 130 μm or less, and the following formulas (1) and (2) are satisfied:
T.sub.M/D≥6  (1); and
T.sub.T/D≥5  (2), where T.sub.M denotes the tensile strength at 90° C. in the MD direction, T.sub.T denotes the tensile strength at 90° C. in the TD direction, and D denotes the density (g/cm.sup.3) of the foam sheet.

One object of the present invention is to provide a polyolefin resin foam sheet suitable as a sealing substrate having both flexibility and heat resistance despite its thinness, and an adhesive tape in which the polyolefin resin foam sheet is used. In order to achieve this, the polyolefin resin foam includes a thermoplastic elastomer, wherein the endothermic peaks measured by a differential scanning calorimeter (DSC) occur in the range of at least 110 C. or more and 143 C. or less and at 153 C. or more, and the thermoplastic elastomer resin is contained at a ratio of 30% by mass or more and 60% by mass or less in 100% by mass of the polyolefin resin.

The present invention relates to a spreading device for a foaming furnace, including a first spreading component and a second spreading component symmetrically mounted on two sides in a hearth of a foaming furnace. Both the first spreading component and the second spreading component are provided with a spreading roll group composed of at least two spreading rolls, and a driving device for driving the spreading roll group. The spreading device further includes a fixing frame, the fixing frame including a first mounting seat and a second mounting seat. The spreading roll includes a first mounting portion and a second mounting portion. The first mounting portion is rotationally connected to the first mounting seat, and the second mounting portion is rotationally connected to the second mounting seat. The spreading device of the present invention has good stability during work, and significantly improves an unfolding effect.

The present invention relates to a spreading device for a foaming furnace, including a first spreading component and a second spreading component symmetrically mounted on two sides in a hearth of a foaming furnace. Both the first spreading component and the second spreading component are provided with a spreading roll group composed of at least two spreading rolls, and a driving device for driving the spreading roll group. The spreading device further includes a fixing frame, the fixing frame including a first mounting seat and a second mounting seat. The spreading roll includes a first mounting portion and a second mounting portion. The first mounting portion is rotationally connected to the first mounting seat, and the second mounting portion is rotationally connected to the second mounting seat. The spreading device of the present invention has good stability during work, and significantly improves an unfolding effect.

There is provided a polyolefin resin foam sheet having a plurality of cells which is formed by foaming a polyolefin resin, wherein, in the polyolefin resin foam sheet, the average cell sizes and the maximum cell sizes in the MD direction and the TD direction are each a predetermined value, and a ratio [TD strength at break/MD average cell size] and a ratio [MD strength at break/TD average cell size] are both 80 kPa/m or more.

There is provided a polyolefin resin foam sheet formed by foaming a polyolefin resin, wherein the expansion ratio of the foam sheet is 1.5 to 20 cm.sup.3/g, the average cell sizes in the MD direction and the TD direction of the foam sheet are 130 m or less, and the following formulas (1) and (2) are satisfied:

T.sub.M/D6(1); and

T.sub.T/D5(2), where T.sub.M denotes the tensile strength at 90 C. in the MD direction, T.sub.T denotes the tensile strength at 90 C. in the TD direction, and D denotes the density (g/cm.sup.3) of the foam sheet.

Provided are a molded article formed of a thermoplastic resin composition, wherein a maximum height (Rmax) of surface roughness of the molded article measured in accordance with JIS B 0601-1982 and a centerline average roughness (Ra) of a surface of the molded article measured in accordance with JIS B 0601-1982 satisfy a formula: 9Rmax/(Ra+1)45, an area ratio of through-holes of the molded article is 1% or more and 20% or less, with a surface area of the molded article being 100%, and a bulk density of the molded article is 0.13 g/cm.sup.3 or more and 0.50 g/cm.sup.3 or less; a method for producing the molded article; and a laminate having the molded article.