Jsp Corporation

Hajime Ohta

Takumi Sakamura

Shota Takagi

Nobumasa Koshita

Kenji Haraguchi

Tomohito Shimada

Takashi Oi

A polypropylene-based resin expanded bead having a tubular shape with a through-hole, containing a foamed core layer constituted by a polypropylene-based resin and a fusion-bonding layer covering the foamed core layer. An average hole diameter d of the through-hole in the expanded bead is less than 1 mm, and a ratio d/D of the average hole diameter d to an average outer diameter D of the expanded bead is 0.4 or less, a mass ratio of the foamed core layer and the fusion-bondable layer is foamed core layer:fusion-bondable layer=99.5:0.5 to 85:15, and the polypropylene-based resin constituting the foamed core layer has a flexural modulus of 800 MPa or more and less than 1200 MPa and a melting point Tmc of 150° C. or lower.

Polypropylene-based resin expanded bead, method for producing same, and molded article of polypropylene-based resin expanded beads

An expanded bead having a tubular shape with a through hole and a method for producing the same are provided. The expanded bead includes a foamed core layer and a covering layer. A polyolefin-based resin included in the covering layer has a melting point lower than a melting point of a polypropylene-based resin included in the foamed core layer. An average hole diameter d of the through hole of the expanded bead is less than 1 mm, and a ratio d/D of the average hole diameter d to an average outer diameter D of the expanded bead is 0.4 or less. The polypropylene-based resin for the foamed core layer has a flexural modulus of 1,200 MPa or more and a melting point of 158° C. or lower.

Expanded bead and method for producing the same

A modified expanded bead that includes an expanded bead which includes a specific base polymer (β) and a coating layer which includes a specific base polymer (α). The coating layer covers at least part of an outer surface of the expanded bead. The melting point Tα of the base polymer (α) and the melting point Tβ of the base polymer (β) satisfy a relationship of 0≤Tα−Tβ≤20. When the modified expanded bead is cut into two halves along a cutting plane to form two half portions and thereafter one of the two half portions is cut along planes perpendicular to the cutting plane to form ten small pieces, outermost pieces among the ten small pieces have a xylene-insoluble content (B) which is less than a xylene-insoluble content (A) in the half portion and the xylene-insoluble content (A) is 10-80% by mass.

Modified expanded bead and foam molded article of expanded beads

A molded article of polypropylene-based resin expanded beads, obtained by in-mold molding of the polypropylene-based resin expanded beads, each bead including: a core layer, in a foamed state, having a polypropylene-based resin; and a covering layer, which covers the core layer, having a polyethylene-based resin. A molded article magnification X [times] of the molded article is 55 times to 90 times, a value of a product X·σof a 50% compressive stress σ[kPa] and the molded article magnification X is 6500 or more, and a 5% compressive stress σof the expanded beads molded article is 5 kPa to 25 kPa.

Molded article of polypropylene-based resin foamed particle molded body, polypropylene-based resin foamed particle, and method for producing same

An expanded bead having a through hole and including a foamed core layer which defines the through hole therein and which is constituted of a resin composition containing two kinds of polypropylene-based resins having different melting points, and a cover layer covering the foamed core layer and constituted of a polyolefin-based resin. The expanded bead gives a DSC curve in which an endothermic peak intrinsic to the resin composition and another endothermic peak on a higher temperature side thereof appear in a specific heat of fusion ratio. Molded articles include a multiplicity of the expanded beads.

Polypropylene-based resin expanded beads and polypropylene-based resin expanded beads molded article

Expandable polylactic acid resin particles including (a) a base resin containing a polylactic acid resin having at least 50 mol % of lactic acid monomer component units, (b) a polyolefin wax in an amount of 0.0001 to 1 part by weight per 100 parts by weight of the base resin, and (c) a blowing agent in an amount of 1 to 30% by weight based on the weight of the resin particles. The expandable resin particles can give expanded beads having an average cell diameter of 10 to 500 &#x3bc;m. The expanded beads can give in-mold foam moldings.

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Yokkaichi, Japan

Hajime Ohta