Twin-sheet thermoforming process

• US 7,157,034 B2
• Filed: 03/15/2004
• Issued: 01/02/2007
• Est. Priority Date: 04/03/2003
• Status: Expired due to Fees

• Current Assignee: AZDEL Incorporated (Hanwha Corporation)
• Original Assignee: AZDEL Incorporated (Hanwha Corporation)
• Inventors: Bristow, Paul A., Hipwell, Jesse G., Hemstreet, Richard D.
• Primary Examiner(s): Johnson; Christina
• Assistant Examiner(s): Daniels; Matthew J.
• Application Number:
  US10/800,505
• Publication Number:
  US 20040197547A1
• Time in Patent Office: 1,023 Days
• Field of Search: 264/510, 264/511, 264/544, 264/545, 264/250
• US Class Current: 264/250
• CPC Class Codes: B32B 2262/101 Glass fibres
• CPC Class Codes: B32B 2307/736 Shrinkable
• CPC Class Codes: B32B 2605/003 Interior finishings
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 37/06 characterised by the heating method
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B60R 13/0225 self supporting head liners
• CPC Class Codes: B60R 13/0815 Acoustic or thermal insulation of passenger compartments wall or roof liners integrating the insulating function B60R13/02; insulating floor mats or carpets B60N3/04
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/31645 Next to addition polymer from unsaturated monomers

Abstract

A twin-sheet thermoforming process for the manufacture of vehicle headliners. In the process a first sheet and second sheet of SuperLite material are mounted onto respective frames. The frames transfer the sheets into an oven, where they are heated to a desired temperature using IR. The first sheet is combined with a cover-stock material using compression molding forming a covered first headliner part. The covered first headliner part is then transferred to a second mold station. The second sheet is heated and then transferred from the oven to the second mold station where it is vacuum-formed on the upper half mold, forming a second headliner part. The upper and lower mold halves are pressed together fusing and sealing the first and second headliner parts into a unified part. The unified part is then unloaded and trimmed as necessary forming a headliner. The SuperLite material used to form the headliner is a sheet of low pressure, thermoformable, thermoplastic composite comprised of polypropylene and long chopped glass fibers.

Claims

1. A thermoform process comprising the steps of:

placing a first sheet in a first frame and transferring the first sheet into an oven, wherein said first sheet is a low pressure, thermoformable, thermoplastic composite comprised of polypropylene and long chopped glass fibers;

heating the first sheet in the oven to a temperature;

placing a second sheet in a second frame and transferring the second sheet into the oven or an alternate oven, wherein said second sheet is a low pressure, thermoformable, thermoplastic composite comprised of polypropylene and long chopped glass fibers;

heating the second sheet in the oven to a temperature;

transferring the heated first sheet to a thermoforming mold having matched mold halves;

transferring a cover-stock material to the thermoforming mold having matched mold halves;

compressing and fusing the cover-stock material to the first sheet forming a compression molded covered first headliner part;

repeating the process until a sufficient number of compression molded covered first headliner parts are formed;

removing the matched mold halves and setting up the mold for vacuum thermoforming with a lower half mold and an opposing half mold;

transferring the compression molded covered first headliner part to the lower half mold of a vacuum thermoforming mold;

transferring the second sheet onto the opposing half mold of the vacuum thermoforming mold;

vacuum molding the second sheet forming a vacuum molded second headliner part;

positioning wiring, duct work or reinforcing components into what will become the interior compartment;

compressing the half molds of the thermoforming mold fusing regions of the compression molded covered first headliner part to the vacuum molded second headliner part, thereby forming a covered unified part comprised of said compression molded covered first headliner part and said vacuum molded second headliner part, where said covered unified part has at least one interior compartment with head impact cushioning; and

ejecting the covered unified part.

2. The thermoform process as claim 1, wherein said first sheet is a low pressure, thermoformable, thermoplastic composite that has a flexural modulus of about 900 MPa to about 1800 MPa as determined by ASTM D792.

3. The thermoform process as claim 1, wherein said second sheet is a low pressure, thermoformable, thermoplastic composite that has a flexural modulus of about 900 MPa to about 1800 MPa as determined by ASTM D792.

4. The thermoform process as claimed in claim 1, wherein the vacuum molded second headliner part is further comprised of a layer of a fusing adhesive.

5. The thermoform process as claimed in claim 1, wherein the cover stock material is comprised of a fabric, a film, or a felt, or a far, or a leather.

6. The thermoform process according to claim 1, wherein the cover stock material is farther comprised of an underlying layer of foam.

7. The thermoform process according to claim 1, wherein the cover stock material is further comprised of an intra-layer adhesive.

8. The thermoform process as claimed in claim 4, wherein compressing the half molds of the thermoforming mold fuses the layer of adhesive on the vacuum molded second headliner part to the compression molded covered first headliner part, thereby forming an adhesively laminated covered unified part.

9. The thermoform process as claimed in claim 1, wherein the covered unified part is a headliner.

10. A thermoform process according to claim 1, further comprising the step of:

after compressing the half molds of the thermoforming mold fusing the compression molded covered first headliner part to the vacuum molded second headliner part Thereby forming the covered unified part;

injecting foam into the interior compartment.

11. A thermoform process according to claim 1, further comprising the step of:

after compressing the half molds of the thermoforming mold fusing the compression molded covered first headliner part to the vacuum molded second headliner part thereby forming the covered unified part;

injecting insulation into the interior compartment.

12. A thermoform process according to claim 1, is further comprised of the step of:

trimming and finishing the covered unified part, where finishing is selected from the processes consisting of;

secondary punching, laser, knife trimming, and vibration, ultrasonic and hot plate welding.

13. A thermoform process according to claim 1, further comprising the step of:

after placing a first sheet in the first frame, transferring the first sheet into a preheat oven;

preheating the first sheet to a temperature.

14. A thermoform process according to claim 13, further comprising the step of:

after placing a second sheet in the second frame, transferring the first sheet into a preheat oven;

preheating the second sheet to a temperature.

15. A thermoform process comprising the steps of:

placing a first sheet in a first frame and transferring the first sheet into an oven;

heating the first sheet in the oven to a temperature;

placing a second sheet in a second frame and transferring the second sheet into the oven or an alternate oven;

heating the second sheet in the oven to a temperature;

transferring the heated first sheet to a thermoforming mold having matched mold halves;

transferring a cover-stock material to the thermoforming mold having matched mold halves;

compressing and fusing the cover stock material to the first sheet forming a compression molded covered first headliner part;

transferring the heated second sheet to a thermoforming mold having matched mold halves;

transferring a reinforcing scrim material to the thermoforming mold having matched mold halves;

compressing and fusing the reinforcing scrim material to the second sheet forming a compression molded scrim reinforced second headliner part;

repeating the process until a sufficient number of compression molded covered first headliner parts and compression molded scrim reinforced second headliner parts are formed;

removing the matched mold halves and setting up the mold for vacuum thermoforming with a lower half mold and an opposing half mold;

transferring the compression molded covered first headliner part to the lower half mold of a vacuum thermoforming mold;

transferring and positioning the compression molded scrim reinforced second headliner part onto the opposing half mold of the vacuum thermoforming mold;

vacuum molding the scrim reinforced second headliner part to form a vacuum molded scrim reinforced second headliner part;

positioning wiring, duct work or reinforcing components into what will become the interior compartment;

compressing the half molds of the thermoforming mold fusing regions of the compression molded covered first headliner part to the vacuum molded scrim reinforced second headliner part, thereby forming a reinforced covered unified part comprised of said compression molded covered first headliner part and said vacuum molded scrim reinforce second headliner part, where said reinforced covered unified part ha at least one interior compartment with head impact cushioning; and

ejecting the reinforced covered unified part.

16. The thermoform process according to claim 15, wherein the cover stock material of the compression molded covered first headliner part is further comprised of an underlying layer of foam.

17. The thermoform process according to claim 16, wherein the cover stock material of the compression molded covered first headliner part is further comprised of an intra-layer adhesive.

18. A thermoform process according to 15, further comprising the step of:

After compressing the half molds of the thermoforming mold fusing the compression molded covered first headliner part to the vacuum molded scrim reinforced second headliner part thereby forming the reinforced covered unified part;

injecting insulation into the interior compartment.