Method for the manufacture of a paper container

• US 4,187,768 A
• Filed: 03/10/1978
• Issued: 02/12/1980
• Est. Priority Date: 11/15/1977
• Status: Expired due to Term

• Current Assignee: Nihon Dixie Company Limited
• Original Assignee: Nihon Dixie Company Limited
• Inventors: Suzuki, Shoichi
• Primary Examiner(s): Bilinsky, Z. R.
• Application Number:
  US05/885,259
• Time in Patent Office: 704 Days
• Field of Search: 93/39.1 R, 93/DIG. 1, 93/55.1 R, 93/36.5, 156/73.1, 156/380, 156/580.1, 53/175, 53/373, 53/379, 229/5.6
• US Class Current: 493/109
• CPC Class Codes: B29C 57/12 Rim rolling
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/12441 being a single wall
• CPC Class Codes: B29C 66/135 Single hemmed joints, i.e. one of the parts to be joined being hemmed in the joint area
• CPC Class Codes: B29C 66/3452 Making complete joints by combining partial joints
• CPC Class Codes: B29C 66/4322 by joining a single sheet to itself B29C66/4332 takes precedence
• CPC Class Codes: B29C 66/49 Internally supporting the, e.g. tubular, article during joining B29C66/63 takes precedence
• CPC Class Codes: B29C 66/542 joining hollow covers or hollow bottoms to open ends of container bodies
• CPC Class Codes: B29C 66/612 Making circumferential joints
• CPC Class Codes: B29C 66/65 with a relative motion between the article and the welding tool B29C65/10, B29C65/12 take precedence
• CPC Class Codes: B29C 66/652 moving the welding tool around the fixed article
• CPC Class Codes: B29C 66/72328 Paper
• CPC Class Codes: B29C 66/7392 characterised by the material of at least one of the parts being a thermoplastic
• CPC Class Codes: B29C 66/81415 being bevelled
• CPC Class Codes: B29C 66/81422 being convex
• CPC Class Codes: B29C 66/81423 being concave
• CPC Class Codes: B29C 66/81425 being stepped, e.g. comprising a shoulder
• CPC Class Codes: B29C 66/81431 comprising a single cavity, e.g. a groove
• CPC Class Codes: B29C 66/81435 comprising several parallel ridges, e.g. for crimping comprising a single ridge B29C66/81427
• CPC Class Codes: B29C 66/81463 : comprising a plurality of single pressing elements, e.g. a plurality of sonotrodes, or comprising a plurality of single counter-pressing elements, e.g. a plurality of anvils, said plurality of said single elements being suitable for making a single joint
• CPC Class Codes: B29C 66/8322 : Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/836 : Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table B29C66/65 takes precedence
• CPC Class Codes: B29C 67/0044 : for shaping edges or extremities B29C57/00 takes precedence
• CPC Class Codes: B29K 2711/123 : Coated
• CPC Class Codes: B29L 2009/00 : Layered products
• CPC Class Codes: B29L 2031/7132 : Bowls, Cups, Glasses
• CPC Class Codes: B31B 2105/0022 : Making boxes from tubular webs or blanks, e.g. with separate bottoms, including tube or bottom forming operations
• CPC Class Codes: B31B 50/60 : Uniting opposed surfaces or edges; Taping
• CPC Class Codes: B31B 50/64 : by applying heat or pressure, e.g. by welding to unite areas where adhesives are applied B31B50/62

Abstract

A method for economically manufacturing a water-resistant paper container having a thermoplastic film coating on the inner and/or outer wall surfaces by means of an ultrasonic wave welding technique. The paper container can be economically manufactured by the utilization of an ultrasonic wave welding technique without the use of any adhesive. According to the method of the present invention, a bottom panel and a body member can be interruptedly joined together at the interface between the panel and the container body. As a result, the inner wall surface of the container can be easily and rapidly lined with a thermoplastic film by a known method. Furthermore, according to the present invention, a container mouth edge which is capable of resisting to any deforming stress can be formed.

Claims

1. A method for the manufacture of a paper container having a substantially non-deformable upper mouth edge comprising the steps of:

blanking out a bottom panel component and a body component from a sheet of paper material having a coating of thermoplastic film applied to at least one side of said paper material, said body component having opposite side ends, an upper edge, a lower end and a lower edge;

downwardly bending the peripheral edge of said bottom panel at right angles to the plane of the bottom panel to form a peripheral flange;

positioning said peripheral flange of the bottom panel slightly above the lower edge of said container body component;

rolling said body component so as to bring the opposite side ends of the container body component into slightly overlapping relationship so as to form a container body wall having a side seam extending in a longitudinal direction along the body wall;

inwardly and upwardly bending the lower end of the container body wall along the peripheral flange of the bottom panel so as to encompass the peripheral flange of the bottom panel to thereby form a bottom seam having said plastic film layer on at least one inner side of said bottom seam;

ultrasonically welding said bottom seam and said side seam by ultrasonic welding means;

outwardly curling the upper circumferential edge of said container body portion to form a container mouth edge, said upper circumferential edge being outwardly curled to fold inwardly back on itself with said plastic film layer of said folded back edge being in face-to-face relationship with a surface portion of said upper circumferential edge to form an upper seam; and

ultrasonically welding said upper seam by using ultrasonic welding means, thereby forming a substantially non-deformable ultrasonically welded upper mouth edge.

2. The method of claim 1 wherein said ultrasonic welding comprises applying ultrasonic waves to said bottom, side and upper seams with a static pressure on the order of from about 1 to 10 Kg/cm² being applied to said seams.

3. The method of claim 2 wherein said static pressure is from about 2 to about 5 Kg/cm².

4. The method of either of claims 2 or 3 wherein said ultrasonic waves are applied for a period of about 0.2 to about 3 seconds.

5. The method of claim 4 wherein said ultrasonic waves are applied for a period of about 0.3 to about 2 seconds.

6. The method of claim 1 wherein said ultrasonic welding comprises applying ultrasonic waves to said seams for a period of about 0.2 to about 3 seconds.

7. The method of claim 6 wherein said ultrasonic waves are applied for a period of about 0.3 to about 2 seconds.

8. The method of claim 1 wherein said outwardly curling step comprises folding said upper circumferential edge back twice on itself, and then ultrasonically welding the facing surfaces thereof.

9. The method of either of claims 1 or 8 wherein said thermoplastic film is on the surface of said paper material which forms the interior of said container.

10. The method of claim 9 wherein said film is exposed at the upper end of the container mouth edge and is undamaged during said ultrasonic welding.

11. The method of claim 9 wherein said thermoplastic film is on both sides of said paper material, said facing surfaces of said container mouth edge being facing thermoplastic film layers, said ultrasonic welding of said upper seams comprising only welding said facing thermoplastic film layers together.

12. The method of claim 11 wherein said film is exposed at the upper end of the container mouth edge and is undamaged during said ultrasonic welding.

13. The method of claim 1 wherein said seams are separately ultrasonically welded.

14. The method of claim 1 comprising softening said upper circumferential edge prior to said outwardly curling step.