Process for the production of a foldable blank of plastic foam by cold forming

• US 5,569,421 A
• Filed: 11/18/1993
• Issued: 10/29/1996
• Est. Priority Date: 05/30/1987
• Status: Expired due to Term

• Current Assignee: Lin Tec Verpackungstechnik GmbH
• Original Assignee: Lin Tec Verpackungstechnik GmbH
• Inventors: Grone, Horst-Ditmar
• Primary Examiner(s): Kuhns, Allan R.
• Application Number:
  US08/154,129
• Time in Patent Office: 1,076 Days
• Field of Search: 264/51, 264/53, 264/284, 264/285, 264/293, 264/295, 264/145, 264/148, 264/150, 264/321, 264/146, 264/297.5
• US Class Current: 264/51
• CPC Class Codes: B29C 2793/00 Shaping techniques involving a cutting or machining operation
• CPC Class Codes: B29C 2793/0063 Cutting longitudinally
• CPC Class Codes: B29C 44/507 extruding the compound through an annular die in general B29C48/03
• CPC Class Codes: B29C 44/5636 with the addition of heat
• CPC Class Codes: B29C 48/00 Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor extrusion blow-moulding B29C49/04
• CPC Class Codes: B29C 48/0012 combined with shaping by internal pressure generated in the material, e.g. foaming
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/0019 combined with shaping by flattening, folding or bending
• CPC Class Codes: B29C 48/0022 combined with cutting
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 53/10 of blown tubular films, e.g. gusseting flattening blown films during extrusion moulding B29C48/03
• CPC Class Codes: B29C 69/001 a shaping technique combined with cutting, e.g. in parts or slices combined with rearranging and joining the cut parts for reinforced material B29C70/545; B29C49/4278, B29C51/268 take precedence
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29L 2023/001 Tubular films, sleeves
• CPC Class Codes: B29L 2031/712 Containers; Packaging elements or accessories, Packages closures therefor B29L2031/56; ink or toner cartridges B29L2031/7678; squeeze tubes B29L2023/20; suitcases B29L2031/7418
• CPC Class Codes: B31B 2105/00 Rigid or semi-rigid containers made by assembling separate sheets, blanks or webs
• CPC Class Codes: B31B 2120/40 lined or internally reinforced

Abstract

Blanks serving for the production of insulating material and folding packs have to be provided with folding and bending lines. These folding and bending lines in the plastic foam must not break when the blank is folded. This is achieved according to the invention by embossing the folding and bending lines for forming the blank into the "fresh" web of material which for the most part still contains expanding agent. The folding and bending lines formed in this way have surprisingly proved to form durable hinge lines in the plastic foam material and make it possible to fold up the blank for forming a folding carton without it breaking or cracking.

Claims

1. A process for producing foldable blanks of plastic foam for forming cartons and insulations, comprising the steps of:

forming a web of material by extruding a foam film tube formed from plastic foam containing an expanding agent;

cooling at least an inner side of said foam film tube by means of a cooling mandrel (15) located inside of said foam film tube; and

, immediately after cooling of said web of material, with at least the most part of said expanding agent being still contained therein, embossing, by cold forming, folding or bending lines in said web of material.

3. The process as claimed in claim 1 or 2, wherein the embossing is conducted when the proportion of expanding agent in the plastic foam is still 100 to 60% in comparison with the expanding agent present during formation of the web of material.

4. The process as claimed in claim 1 or 2, wherein the blanks are severed from the web of material after said bending and folding lines have been embossed.

5. The process as claimed in claim 4, wherein each blank is severed from the web of material by means of an embossing cut forming encircling cutting lines.

6. The process as claimed in claim 1 or 2, wherein, simultaneously with the embossing of the bending and folding lines, at least one blank is severed from the web of material.

7. The process as claimed in claim 6, wherein several blanks lying next to one another are severed together from the web of material, with the embossing and/or folding lines being formed simultaneously on all the severed blanks.

8. The process as claimed in claim 6, wherein each blank is severed from the web of material by means of an embossing cut forming encircling cutting lines.

9. The process as claimed in claim 1 or 2, wherein polystyrene is used as a plastic foam.

2. A process for producing foldable blanks of plastic foam for forming cartons and insulations, comprising the steps of:

forming a web of material by extruding a foam film tube formed from plastic foam containing an expanding agent;

cutting open said foam film tube;

forming a flat web of material from the cut foam material; and

, immediately after cooling of said web of material, with at least the most part of said expanding agent being still contained therein, embossing, by cold forming folding or bending lines in said web of material.

10. The process as claimed in claim 2, wherein said cooling is achieved by cooling at least an inner side of said foam film tube by means of a cooling mandrel (15) located inside of said foam film tube.

11. A process for producing foldable blanks of plastic foam, comprising the steps of:

forming a web of material from heated plastic foam containing an expanding agent;

then, cooling the web; and

then, immediately after cooling, and before more than 40% of the expanding agent, which was in the plastic foam during said forming step, has evaporated from the foam, embossing, by cold forming, folding lines in the cooled web.

12. The process as claimed in claim 11, wherein said forming step comprises extruding the web from the heated plastic foam.

13. The process as claimed in claim 12, wherein the embossing step is performed while substantially 100% of the expanding agent that was in the plastic foam during the forming step remains in the cooled web.