Prime Polymer Co., Ltd.

Mitsui Chemicals, Inc.

Tatsuji Kawamura

Ikunori Sakai

Tomoyuki Obara

Tatsuya Kusumoto

Yukio Ishii

Akinori Nagano

Hideo Akimoto

Mitsuru Watari

Takashi Miyazaki

Toru Fukada

Kazuhiro Doi

In a polypropylene-based foamed molded body of the present invention, a density which is measured on the basis of ISO1183 is greater than or equal to 0.15 g/cmand less than or equal to 0.54 g/cm, thermal resistance (R) at 30&#xb0; C. in a thickness direction which is measured on the basis of ASTM E1530 is greater than or equal to 0.020 m&#xb7;K/W and less than or equal to 0.125 m&#xb7;K/W, thermal capacity per unit area (Q) at 30&#xb0; C. is greater than or equal to 1.0 kJ/m&#xb7;K and less than or equal to 2.5 kJ/m&#xb7;K, and Expression 1 described below is satisfied.&#x3e;1/(4&#xd7;)&#x2003;&#x2003;(Expression 1)

Polypropylene-based foamed molded body and manufacturing method of polypropylene-based foamed molded body

To provide an expansion injection molding process, which is freed from the occurrence of swirl marks on the surface of a molded article and by which foamed injection moldings having good appearance can be produced in a short molding cycle and at a low cost; and a mold for expansion injection molding. A movable moldis moved toward a fixed mold, whereby a sealing memberset on at least one of a pair of facing surfaces of the moldand moldin the outside of a cavity is brought into contact with the other of the facing surfaces or a sealing memberset thereon to make the cavitygas-sealed state. While keeping the gas-sealed state, the movable moldis further moved toward the fixed moldwith the sealing membercompressed, whereby the volume of the cavityis decreased to enhance the pressure in the cavityto a level exceeding the atmospheric pressure. Then, a thermoplastic resin is injected into the cavityof an enhanced pressure.

Expansion injection molding process and mold for expansion injection molding

Foaming polypropylene resin compositions are excellent in balance between melt tension and flowability, can give injection-molded foams having superior mechanical strength such as impact resistance, and are suited for the production of automobile parts or the like. Processes of the invention produce injection-molded foams from the compositions. A foaming polypropylene resin composition according to the present invention includes a polypropylene resin (A) and an ethylene/&#x3b1;-olefin having 3-10 carbon atoms copolymer (B) in a specific ratio; the ethylene/&#x3b1;-olefin having 3-10-carbon atoms copolymer (B) includes a higher molecular weight component (B-H) having MFRof 1 to 10 g/10 min and a lower molecular weight component (B-L) having MFRof 20 to 50 g/10 min; and the weight ratio between (B-H) and (B-L), (B-H):(B-L), is in the range of 6:4 to 2:8.

Foaming polypropylene resin composition and process for producing injection-molded foams from the composition

An injection-molding die including: a fixed die; a movable die; a cavity defined by the fixed die and the movable die; and a gate for injecting a melt resin into the cavity. The cavity includes: a flow-dividing structure that divides a flow of the melt resin injected into the cavity into a plurality of resin flows; and a flow-advancing area in which the resin flows generated by the flow-dividing structure are merged together. The flow-advancing area is formed thicker than a flow-hesitating area of the flow-advancing area in the cavity.

Injection molding metal mold and shaped article

A process is provided for producing a foamed article of a thermoplastic resin composition having a relatively thicker solid skin layer exhibiting better appearance without occurrence of a swirl mark and having a foam structure of relatively uniform foam cell size with better foam cell configuration, which is light-weighing and superior in stiffness, in an easy and efficient manner, by causing the resin composition to foam up in a cavity of a mold.

Growing community of inventors

Ichihara, Japan

Tatsuji Kawamura