Kaneka Corporation

Other

Tomonori Iwamoto

Takema Yamaguchi

Kenichi Senda

Minori Yamaguchi

Taro Kiguchi

Tetsuya Shibata

Takayuki Goda

Tetsuya Ogita

John Bready Stuart

Takayuki Gouda

Steven Charles Skarke

An object of the present invention is to provide an in-mold foamed article having good surface appearances and high rigidity produced by using a common molding machine that withstands a pressure of up to 0.4 MPa. The present invention provides polypropylene resin pre-expanded particles containing a base resin which is a resin having a melt flow rate of 5 g/10 min or more and 20 g/10 min or less and a melting point of 140&#xb0; C. or higher and 155&#xb0; C. or lower and satisfying the conditional formula below, and an in-mold foamed article produced from molding the pre-expanded particles:[Heat of crystal fusion (J/g)]&#x2267;1.2&#xd7;[Melting point (&#xb0; C.)]&#x2212;96.

Polypropylene resin pre-expanded particles and in-mold foamed articles prepared therefrom

It is an object of the present invention to provide a method for easily and economically producing an expansion-molded polypropylene-based resin article stably with a high porosity, that has continuous voids and that can be used as materials such as a sound absorbing material and a draining material. More specifically, the present invention relates to a method for producing an expansion-molded polypropylene-based resin article, in which a mold is filled with expanded polypropylene-based resin particles, and the expanded particles are heated and fused using water vapor, and then cooled, wherein expanded polypropylene-based resin particles are used in which a polypropylene-based resin having a melt index (MI) of not less than 0.1 g/10 minutes and not more than 9 g/10 minutes is used as a base resin, a cell size is not more than 150 &#x3bc;m, two melting peaks are present on a DSC curve obtained by differential scanning calorimetry, and &#x3b2;/(&#x3b1;+&#x3b2;) is not less than 0.35 and not more than 0.75 when taking a melting calorie at the lower temperature peak as &#x3b1; (J/g) and taking a melting calorie at the higher temperature peak as &#x3b2; (J/g), and a porosity of an obtained molded article is not less than 20% and not more than 50%.

Method for producing expansion-molded polypropylene-based resin article

The present invention provides a pre-expanded particulate polyolefin-based resin capable of easily attaining satisfactory secondary expandability, satisfactory surface appearance, and satisfactory dimensional stability even when it is intended to obtain an in-mold expansion molded article having a thin-wall shape. The present invention provides a pre-expanded particulate polypropylene-based resin including a polypropylene-based resin X as a base resin, where the resin X includes a resin mixture of at least a polypropylene-based resin A having a melting point of 140&#xb0; C. or lower and a polypropylene-based resin B having a melting point of 145&#xb0; C. or higher, and the resin mixture is modified by an organic peroxide so as to have a melt index of 5 g/10 min or more and less than 20 g/10 min.

Pre-expanded particulate polypropylene-based resin and in-mold expansion molded article

Flame retardant polyolefin pre-expanded particles made of a resin composition comprising a polyolefin resin and a sterically hindered amine ether flame retardant, which can be molded with good moldability to give in-mold foamed articles which have an excellent flame resistance and do not generate harmful gas at the time of burning.

Flame retardant polyolefin resin pre-expanded particles and in-mold foamed articles prepared therefrom

The present invention provides polypropylene resin pre-expanded particles having small fluctuation in cell diameter and expansion ratio compared to in the past. The pre-expanded particles are obtained by having as a base resin, a polypropylene resin composition comprising polypropylene resin (A), a compound having a triazine skeleton and molecular weight of at most 300 per triazine skeleton unit (B) and as a random component, hydrophilic polymer (C) and inorganic filler (D) and water as the foaming agent. By using the pre-expanded particles, a polypropylene resin in-mold expanded article having decreased unevenness in color and fluctuation in weight can be obtained.

Polypropylene resin pre-expanded particle and in-mold expanded article thereof

Pre-expanded polypropylene resin beads and process for producing molded object therefrom by in-mold foaming

Polyolefin resin pre-expanded particles having two fusion peaks on DSC curve wherein the proportion of the heat of fusion Qh of the peak appearing on the high temperature side based on the total heat of fusion of the two peaks represented by the equation: &lsqb;Qh/(Ql&plus;Qh)&rsqb;&times;100 falls within the range of 10 to 60% in which Ql is the heat of fusion of the peak appearing on the low temperature side, and the standard deviation of said proportion is not more than 1.2. The pre-expanded particles are prepared by releasing an aqueous dispersion of resin particles impregnated with a blowing agent from a vessel into an atmosphere of lower pressure than the inner pressure of the vessel to expand the particles, while stepwise or continuously raising the inner temperature or the inner pressure of the vessel at a specific rate, and can be molded with stable molding cycle to give cellular molded articles having stable dimensions.

Polyolefin resin pre-expanded particles and process for preparing the same

A method of washing pre-expanded particles having a substantially water insoluble inorganic compound attached thereto by contacting the pre-expanded particles with an aqueous washing solution of a water soluble compound. The water soluble compound has a solubility with water of at least 1 g/100 g of water and has 1-500 surface bonding functional groups and 1-500 hydrophilic functional groups. At least one of the surface bonding functional groups of the water soluble compound attaches to the water insoluble inorganic compound.

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Settsu, Japan

Tomonori Iwamoto