Multistage process for producing hollow plastic articles from half shells

• US 8,617,344 B2
• Filed: 09/28/2012
• Issued: 12/31/2013
• Est. Priority Date: 07/12/2002
• Status: Expired due to Term

• Current Assignee: Basell Polyolefine GmbH (Lyondellbasell Industries NV)
• Original Assignee: Basell Polyolefine GmbH (Lyondellbasell Industries NV)
• Inventors: Rohde, Wolfgang, Sattel, Rainer, Schnorr, Jrg, Springholz, Bernhard, Weinlein, Roger, Meyer, Jrg, Wst, Andreas
• Primary Examiner(s): Goff, John
• Application Number:
  US13/631,610
• Publication Number:
  US 20130025778A1
• Time in Patent Office: 459 Days
• Field of Search: 156/245, 156/308.2, 156/309.6, 156/309.9, 156/244.11, 156/244.13, 156/244.18, 156/244.22, 156/244.24, 156/196, 156/292, 156/308.4, 264/146, 264/147, 264/152, 264/510, 264/515, 264/516, 264/523, 264/544, 264/545
• US Class Current: 156/308.2
• CPC Class Codes: B26D 3/001 Cutting tubes longitudinally
• CPC Class Codes: B29C 2049/2073 Means for feeding the inserts into the mould, preform or parison, e.g. grippers
• CPC Class Codes: B29C 2793/00 Shaping techniques involving a cutting or machining operation
• CPC Class Codes: B29C 2793/0054 partially cutting through the material
• CPC Class Codes: B29C 2793/0063 Cutting longitudinally
• CPC Class Codes: B29C 2793/0081 before shaping
• CPC Class Codes: B29C 48/001 Combinations of extrusion moulding with other shaping operations
• CPC Class Codes: B29C 48/0011 combined with compression moulding
• CPC Class Codes: B29C 48/0017 combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/0022 combined with cutting
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 49/00 Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
• CPC Class Codes: B29C 49/04 Extrusion blow-moulding
• CPC Class Codes: B29C 49/0691 using sheet like material, e.g. sheet blow-moulding from joined sheets
• CPC Class Codes: B29C 49/06914 using parallel sheets as a preform
• CPC Class Codes: B29C 49/06916 Means for avoiding parts of the sheets to stick together, e.g. to provide blow opening
• CPC Class Codes: B29C 49/071 Preforms or parisons characterised by their configuration, e.g. geometry, dimensions or physical properties
• CPC Class Codes: B29C 49/20 of articles having inserts or reinforcements ; Handling of inserts or reinforcements
• CPC Class Codes: B29C 49/22 using multilayered preforms or parisons
• CPC Class Codes: B29C 51/00 : Shaping by thermoforming , i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor blow moulding of tubular preforms B29C49/00, deforming of tubular or hollow preforms B29C67/0014
• CPC Class Codes: B29C 51/267 : Two sheets being thermoformed in separate mould parts and joined together while still in the mould B29C49/0691 takes precedence
• CPC Class Codes: B29C 65/02 : by heating, with or without pressure
• CPC Class Codes: B29C 65/028 : making use of inherent heat, i.e. the heat for the joining comes from the moulding process of one of the parts to be joined
• CPC Class Codes: B29C 65/48 : using adhesives , i.e. using supplementary joining material; solvent bonding
• CPC Class Codes: B29C 66/54 : Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• CPC Class Codes: B29C 66/543 : joining more than two hollow-preforms to form said hollow articles
• CPC Class Codes: B29C 66/71 : characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/7234 : comprising a barrier layer
• CPC Class Codes: B29C 66/8322 : Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/9121 : by measuring the temperature
• CPC Class Codes: B29C 66/9141 : by controlling or regulating the temperature
• CPC Class Codes: B29K 2023/06 : PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/065 : HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2023/086 : EVOH, i.e. ethylene vinyl alcohol copolymer
• CPC Class Codes: B29K 2023/12 : PP, i.e. polypropylene
• CPC Class Codes: B29K 2027/06 : PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2027/12 : containing fluorine
• CPC Class Codes: B29K 2027/16 : PVDF, i.e. polyvinylidene fluoride
• CPC Class Codes: B29K 2059/00 : Use of polyacetals , e.g. POM, i.e. polyoxymethylene or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2067/00 : Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2067/006 : PBT, i.e. polybutylene terephthalate
• CPC Class Codes: B29K 2077/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0082 : Flexural strength; Flexion stiffness
• CPC Class Codes: B29L 2009/00 : Layered products
• CPC Class Codes: B29L 2022/00 : Hollow articles tubular articles B29L2023/00; pneumatic tyres B29L2030/00
• CPC Class Codes: B29L 2031/7172 : Fuel tanks, jerry cans
• CPC Class Codes: B32B 1/00 : Layered products having a non-planar shape
• CPC Class Codes: B32B 2250/24 : All layers being polymeric
• CPC Class Codes: B32B 2270/00 : Resin or rubber layer containing a blend of at least two different polymers
• CPC Class Codes: B32B 2272/00 : Resin or rubber layer comprising scrap, waste or recycling material
• CPC Class Codes: B32B 2307/714 : Inert, i.e. inert to chemical degradation, corrosion
• CPC Class Codes: B32B 2307/718 : Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2307/7242 : Non-permeable
• CPC Class Codes: B32B 2307/7265 : Non-permeable
• CPC Class Codes: B32B 2439/40 : Closed containers
• CPC Class Codes: B32B 2439/60 : Bottles
• CPC Class Codes: B32B 2605/08 : Cars
• CPC Class Codes: B32B 27/08 : of synthetic resin
• CPC Class Codes: B32B 27/304 : comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/32 : comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 : comprising polyamides
• CPC Class Codes: B32B 27/36 : comprising polyesters
• CPC Class Codes: B32B 27/42 : comprising condensation resins of aldehydes, e.g. with phenols, ureas or melamines
• CPC Class Codes: Y10T 156/1062 : Prior to assembly
• CPC Class Codes: Y10T 428/1352 : Polymer or resin containing [i.e., natural or synthetic]

Abstract

The present invention relates to a multistage process for producing hollow plastic articles, encompassing the following steps:

• a) producing a tubular plastic parison by means of extrusion or coextrusion;
• b) cutting open the plastic parison to produce two planar-surface parts;
• c) molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another at least along the peripheral edges, so that the semifinished products/half shells are not in contact with one another;
• d) opening the mold halves and removing the intermediate frame;
• e) closing the mold halves, with the result that the half shells come into contact with one another along a peripheral rim; and
• f) bonding the half shells to give a hollow article.

Claims

1. A process for producing hollow plastic articles comprising the steps:

a) producing a tubular plastic parison by means of extrusion or coextrusion;

b) cutting open the tubular plastic parison with a cutting device to produce two planar-surface parts using pneumatically driven rollers arranged in the immediate vicinity of the cutting device for distancing the two planar-surface parts from the cutting device immediately after separation of the parison;

c) molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another at least along peripheral edges, wherein the planar-surface parts and half shells are not in contact with one another;

d) opening the mold halves and removing the intermediate frame;

e) closing the mold halves, wherein the half shells come into contact with one another along a peripheral rim; and

f) bonding the half shells

wherein the driven rollers are integrated within the cutting device.

2. The process of claim 1 wherein the cutting device is a triangular cutting knife.

3. The process of claim 1 wherein after removal of the intermediate frame, incorporated parts are attached to the inside of at least one of the molded half shells.

4. The process of claim 3 wherein the incorporated parts are chosen from ventilation lines for pressure equilibration within a tank, fuel lines for equilibration of liquids within the tank, valves, anti-surge cups, pump-related sensor modules and tank sensor modules.

5. The process of claim 1 wherein the planar-surface parts are molded in the mold halves to give half shells by means of at least one of thermoforming and blow molding.

6. The process of claim 1 wherein the bonding of the half shells comprises at least one of adhesive bonding and welding.

7. The process of claim 5 wherein heat from thermoforming is used to weld the half shells.

8. The process of claim 1 further comprising molding of the hollow article by at least one of thermoforming and blow molding after bonding of the half shells.

9. The process of claim 1 wherein the intermediate frame comprises a plate insert which substantially provides complete filling of an area between the two mold halves.

10. The process of claim 1 wherein the intermediate frame comprises equipment for cooling or heating.

11. The process of claim 1 wherein the intermediate frame comprises equipment for controlled heating of the edges of the molded half shells.

12. The process of claim 1 wherein the intermediate frame comprises equipment for heating a pinch-off edge of at least one mold half.

13. The process of claim 9 wherein the intermediate frame or the plate insert is of single-part or multipart design.

14. The process of claim 1 which proceeds without additional heating steps or cooling steps.

15. The process of claim 1 wherein the cutting of the tubular plastic parison takes place before the extrusion process is complete.

16. The process of claim 1 wherein the plastic parison comprises at least one layer made from polymeric material.

17. The process of claim 1 wherein the plastic parison comprises a structure of at least two layers.

18. The process of claim 1 wherein the plastic parison comprises a structure of at least two layers wherein the at least two layers are arranged, from the outside to the inside:

(1). a layer made from HDPE with thickness from 5 to 30%;

(2). a regrind layer with thickness from 10 to 82%;

(3). an adhesion-promoter layer with thickness from 1 to 5%;

(4). a barrier layer with thickness from 1 to 10%;

(5). an adhesion-promoter layer with thickness from 1 to 5%; and

(6). a layer made from HDPE having a thickness from 10 to 40%, based in each case on a total thickness of the plastic article wall.

19. The process of claim 12 wherein the intermediate frame has equipment for heating a pinch-off edge of both mold halves.

20. The process of claim 16 wherein the polymeric material is selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polyamide, polyketone, polyester, and mixtures thereof.

21. The process of claim 17 wherein the at least two layers comprise a base layer and at least one of a regrind layer, and adhesion-promoter layer and a barrier layer.

22. A process for producing hollow plastic articles, comprising the following steps:

a). producing a tubular plastic parison by means of extrusion or coextrusion;

b). cutting open the tubular plastic parison with a cutting device to produce two planar-surface parts using pneumatically driven rollers arranged in the immediate vicinity of the cutting device for distancing the two planar-surface parts from the cutting device immediately after separation of the parison;

c). controlling the distance between the two planar-surface parts with guide rollers;

d). molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another at least along peripheral edges, wherein the planar-surface parts and half shells are not in contact with one another;

e). opening the mold halves and removing the intermediate frame;

f). closing the mold halves, wherein the half shells come into contact with one another along a peripheral rim; and

g). bonding the half shells wherein the driven rollers are integrated within the cutting device.