Kaneka Corporation

Ryoji Nakayama

Ryuta Kutsumizu

Kenji Mogami

Tetsuo Okura

Kirito Suzuki

Shotaro Maruhashi

Yoshihito Yano

Terumasa Abe

Expandable styrene resin particles include 2.0 wt % to 8.0 wt % of graphite, and the graphite has a mean particle size of 2.5 &#x3bc;m to 9 &#x3bc;m. The expandable styrene resin particles satisfy (i) a laser scattering intensity per unit solution concentration of the graphite is not less than 5 {%/(mg/ml)}/wt %, (ii) an area of the graphite per unit solution concentration of the graphite in 1 mmis not less than 55 ({mm/mm}/{g/g}), or (iii) when the expandable styrene resin particles are pre-expanded and are made into an expanded molded product having an expansion ratio of 40 times, a value (%/wt %) obtained by dividing, by the content of the graphite (wt %), a percentage of an area occupied by the graphite in a surface layer of the expanded molded product (%), a quotient of which is further multiplied by 100, is not less than 100.

Expandable styrene resin particles, pre-expanded particles of styrene resin, styrene resin foam molded body, and method for producing expandable resin particles

Pre-expanded polypropylene-based resin particles include a polypropylene-based resin. The polypropylene-based resin satisfies tan &#x3b4;&#x2264;0.32&#xd7;V+0.1, where tan &#x3b4; represents a loss tangent at an angular frequency of 0.1 rad/s in dynamic viscoelastic behavior measurement at 200&#xb0; C. and V represents a melt fracture take-up speed (m/min) at 200&#xb0; C.

Polypropylene-type resin pre-expanded particles, and method for producing said pre-expanded particles

A polypropylene resin and a polypropylene resin composition are provided, which have excellent fluidity and foaming properties, and particularly in use for foam injection molding, allow molding with a narrow initial cavity clearance even if a large mold is used, and therefore can provide a thin, large-area foam-injection-molded article having good appearance. The invention relates to a polypropylene resin obtained by melt mixing a linear polypropylene resin, a radical polymerization initiator and a conjugated diene compound, wherein the polypropylene resin has a melt flow rate of more than 30 g/10 min and not more than 250 g/10 min as measured at 230&#xb0; C. under a load of 2.16 kg; a melt tension at 200&#xb0; C. of not less than 0.3 cN; and a loss tangent (tan &#x3b4;) of not more than 6.0, the loss tangent being a ratio of loss modulus to storage modulus at an angular frequency of 1 rad/s in dynamic viscoelasticity measurement at 200&#xb0; C., and also relates to a polypropylene resin composition for foam injection molding, containing the polypropylene resin.

Polypropylene resin, polypropylene resin composition, and foam-injection-molded article

A polypropylene-based resin composition for injection foam molding, containing (A) 50 to 95 parts by weight of a linear polypropylene-based resin having a melt flow rate of from 10 g/10 min. to 100 g/10 min. and a melt tension of 2 cN or less and (B) 5 to 50 parts by weight of a modified polypropylene having a melt flow rate of from 0.1 g/10 min. to less than 10 g/10 min. and a melt tension of 5 cN or more and exhibiting a strain hardening property (provided that a total of the resin (A) and the resin (B) is 100 parts by weight) and a foaming agent are supplied to an injection molding machine to be injected into a die, thereby achieving a foam molding. It is thus possible to obtain a injection foamed molded article which has a satisfactory injection foam moldability, a skin layer having little silver streaks or the like on its surface, and an internal core layer having a foam of high expansion ratio and uniformly fine and a excellent appearance glossiness, lightweightness, and rigidity at a low cost.

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Osaka, Japan

Ryoji Nakayama