Claims
- 1. A method of preparing a cylindrical member for a paper container, which comprises the steps of:
- providing a laminated sheet having a paper layer and an exposed layer of a thermoplastic polyester resin, said polyester resin being polyethylene terephthalate comprising terephtalic acid units and ethylene glycol units as main polymeric components and 3 to 20 mol % of copolymeric components:
- forming a preform sheet by folding back an edge of said laminated sheet in a manner such that said polyester layer is exposed on both sides of the folded edge;
- irradiating said polyester layer of the folded edge and the polyester layer of another edge of said preform sheet by a carbon dioxide gas laser beam in a direction respectively vertical to said folded edge and said another edge and directly converting said carbon dioxide laser beam to thermal energy in said layers and softening said layers;
- forming a cylindrical member with an overlapped portion by placing said another edge over said folded edge; and
- pressing said overlapped portion to seal said another edge and folded edge together.
- 2. The method as claimed in claim 1, wherein said irradiating is conducted after formation of said preform sheet into a nearly cylindrical shape before overlapping said folded edge with said another edge.
- 3. The method as claimed in claim 1, wherein said carbon dioxide gas laser provides a sealing width of from 2 to 25 mm.
- 4. The method for preparing a cylindrical member for a paper container according to claim 1, wherein said perform sheet is prepared by skiving said paper layer at an edge of said laminated sheet and folding back the skived edge.
- 5. A method of preparing a cylindrical member for a paper container, which comprises the steps of:
- providing a laminated sheet having a paper layer, an exposed layer of a thermoplastic polyester resin and an aluminum layer between said paper layer and said exposed polyester layer;
- forming a preform sheet by folding back an edge of said laminated sheet in a manner such that said polyester layer is exposed on both sides of the folded edge;
- irradiating said polyester layer of the folded edge and the polyester layer of another edge of said preform sheet by a carbon dioxide gas laser beam in a direction respectively vertical to said folded edge and said another edge and directly converting said carbon dioxide laser beam to thermal energy in said layers and softening said layers;
- forming a cylindrical member with an overlapped portion by placing said another edge over said folded edge; and
- pressing said overlapped portion to seal said another edge and folded edge together.
- 6. The method as claimed in claim 5, wherein said irradiating as conducted after formation of said preformed sheet into a nearly cylindrical shape before overlapping said folded edge with said another edge.
- 7. The method as claimed in claim 5, wherein said carbon dioxide gas laser provides a sealing width of from 2 to 25 mm.
- 8. The method as claimed in claim 5, wherein said polyester resin is polyethylene terephthalate comprising terephthalic acid units and ethylene glycol units as main polymeric components and 3 to 20 mol % of copolymer components.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2-198277 |
Jul 1990 |
JPX |
|
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a continuation of Ser. No. 07/838,200, filed Mar. 6, 1992, abandoned.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/JP91/00980 |
7/23/1991 |
|
|
3/6/1992 |
3/6/1992 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO92/01559 |
2/6/1992 |
|
|
US Referenced Citations (11)
Foreign Referenced Citations (5)
Number |
Date |
Country |
0237192 |
Sep 1987 |
EPX |
0398447 |
Nov 1990 |
EPX |
1256527 |
Dec 1967 |
DEX |
3023835 |
Jan 1981 |
DEX |
8910231 |
Nov 1989 |
WOX |
Non-Patent Literature Citations (1)
Entry |
Research Disclosure, Sep. 1981, HAVANT GB, pp. 358-359 RD20941 `laser bonding of plastic parts (D. R. Schmith)`. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
838200 |
Mar 1992 |
|