US 3,967,991 AGranted

Method for producing receptacles from thermoplastic resin foam sheet

AssigneeSekisui Kaseihin Kogyo Kabushiki Kaisha

InventorsIkuya Shimano, Takashi Matsui

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Abstract

A method for producing receptacles of a thermoplastic resin foam sheet, which comprises forming a cylinder of a rectangular-shaped uni-directionally shrinkable thermoplastic resin foam sheet which, when heated, shrinks in a first direction to a greater extent than other directions perpendicular to said first direction, so that when heated, the thermoplastic resin foam sheet will shrink toward the central axis of the cylinder; bonding the side edges of the sheet forming the cylinder; heating the foam sheet on a molding form to a temperature above the softening point of the resin, whereby the cylindrical foam sheet shrinks toward the central axis of the cylinder formed by the sheet and intimately contacts the circumferential side wall of the molding form to form a bottomless or gathered cylindrical article; and compression-molding the article under heat to form a thermostatic resin foam receptacle.

Claims14

Dependent claims

A method for producing receptacles of a thermoplastic resin foam, which comprises the steps of:

forming a cylinder of a rectangular-shaped unidirectionally shrinkable thermoplastic resin foam which, when heated, shrinks in a first direction to a greater extent than other directions perpendicular to said first direction, so that when heated, said thermoplastic resin foam sheet will shrink toward the central axis of said cylinder;
bonding the side edges of said sheet forming said cylinder;
heating said foam sheet on a male mold member of a mold comprising a male mold member and a female mole member, having a hollow part provided at the upper part of a mold cavity formed by said male mold member and said female mold member, and which can be heated and cooled to a temperature above the softening point of said resin, whereby said cylindrical foam sheet shrinks toward the central axis of said cylinder formed by said sheet and intimately contacts the circumferential side wall of said male mold member to form a bottomless cylindrical article, said male mold member being of a size such that a portion of said foam sheet extends beyond one end surface of said male mold member;
further bending the circumferential edge of said cylinder formed by said sheet which extends beyond said end surface of said male mold member to circumferentially cover the edge of said male mold member;
inserting the resulting cylindrical article on said male mold member into said female mold member together with a bottom plate for said bottomless cylindrical article so that the bottom portion of said cylindrical article is adjacent said bottom plate;
compression-molding said article under heat thereby bonding said bottom plate to the bottom of said cylindrical article;
and
pressing the upper edge of said cylindrical article which is positioned at said hollow part under heat to form a rib which reduces a volume.

5 more elements

A method of producing receptacles of a thermoplastic resin foam sheet, which comprises the steps of:

forming a cylinder of a rectangular-shaped unidirectionally shrinkable thermoplastic resin foam sheet which, when heated, shrinks in a first direction to a greater extent than other directions perpendicular to said first direction, so that when heated, said thermoplastic resin foam sheet will shrink toward the central axis of said cylinder;
bonding the side edges of said sheet forming said cylinder;
heating said foam sheet on a molding form to a termperature above the softening point of said resin, whereby said cylindrical foam sheet shrinks toward the central axis of said cylinder formed by said sheet and intimately contacts the circumferential side wall of said molding form to form a bottomless cylindrical article, said molding form being of a size such that a portion of said form sheet extends beyond one end surface of said molding form;
further bending the circumferential edge of said cylinder formed by said sheet which extends beyond said end surface of said molding form to circumferentially cover the circumferential edge of said molding form;
removing the resulting cylindrical article from said molding form;
inserting the resulting cylindrical article on a male mold member of a mold, comprising a male mold member and a female mold member, having a hollow part provided at the upper part of a mold cavity formed by said male mold member and said female mold member, which can be heated and cooled;
inserting said male mold member having said cylindrical article together with a bottom plate for said cylindrical article so that the bottom portion of said cylindrical article is adjacent said bottom plate into the female mold member of said mold;
compression-molding said article under heat thereby bonding said bottom plate to the bottom of said cylindrical article;
and
pressing the upper edge of said cylindrical article which is positioned at said hollow part under heat to form a rib which reduces in volume.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/422,958Filed 7 Dec 1973
Priority: JA 47-1235958 Dec 1972
Granted: 6 Jul 1976
Term ends: Not estimatedThe source records don’t support an estimate.

Classification25 codes

B29D 22/003
Producing hollow articles: containers for packaging, storing or transporting, e.g. bottles, jars, cans, barrels, tanks
B29C 43/02
Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor: of articles of definite length, i.e.…
B29C 53/44
Using internal forming surfaces, e.g. mandrels: rotatable about the axis of the article
B29C 57/10
Shaping of tube ends, e.g. flanging, belling or closing; Apparatus therefor , e.g. collapsible mandrels: closing