Co-injection molding of the structural portion of a vehicle liftgate inner panel

Patent metadata

Field	Value
Publication number	US-2016167262-A1
Application number	US-201314436708-A
Country	US
Kind code	A1
Filing date	Oct 18, 2013
Priority date	Oct 19, 2012
Publication date	Jun 16, 2016
Grant date	—

Abstract

A thermoplastic liftgate inner panel construction is provided by using a co-injected injection molding process. In a first phase, a class A surface material is injected into the molds and thereafter in a second phase an inner core of material is injected using a gas-infused reinforced polymer.

First claim

What is claimed is:

1 . A thermoplastic vehicle body closure panel for a vehicle comprising:
an outer surface layer of a thermoplastic injection moldable material having a class A forming surface on at least part of said thermoplastic vehicle body closure panel; and at least one structural member substantially filled with a foam core.

2 . The thermoplastic vehicle body closure panel of claim 1 , wherein the foamed core includes microcellular spaces for reducing weight and providing structural support.

3 . A process for manufacture of a thermoplastic vehicle body closure panel comprising:
providing a mold having at least part thereof capable of forming a Class A surface and configured for injection of a supercritical fluid into predetermined class A areas of the molded liftgate inner panel; providing an injection moldable thermoplastic material; and injection molding the thermoplastic vehicle body closure panel structure from said thermoplastic material in a first step with injection of a combination of said supercritical fluid and a second thermoplastic material into said predetermined areas of said mold after the class A surface of the mold is pre-covered in thermoplastic material.

4 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 3 , wherein a sequential valve gate mold is used for the process.

5 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 4 , wherein a two shot nozzle is used.

6 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 4 , wherein virgin show surface thermoplastic is injected first at a first portion of the mold and said second thermoplastic material is injected at a separate location along with said supercritical fluid.

7 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 3 , wherein said thermoplastic is a virgin thermoplastic resin.

8 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 3 , wherein the part produced is greater than 3 mm thick at all areas of the part.

9 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 3 , wherein the part is produced to be from 4-6 mm thick.

10 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 3 , further comprising molding a continuously molded structure including at least a first cosmetic area, a second structural area and a third attachment area, and wherein said second structural area and third attachment area are said predetermined areas for injection of said supercritical fluid and said second thermoplastic material.

11 . A thermoplastic vehicle body closure panel for a vehicle comprising:
a continuously molded structure including at least a first cosmetic area, a second structural area and a third attachment area, each of said first second and third areas having a thickness of greater than 3 mm and including an outer surface of a thermoplastic injection moldable material having a class A forming surface on at least part of said liftgate inner panel and substantially filled with a micro cellular enhanced foam core.

12 . The thermoplastic vehicle body closure panel of claim 11 , wherein the foamed core includes microcellular spaces for reducing weight and providing structural support at least in the third attachment and second structural areas.

13 . The thermoplastic vehicle body closure panel of claim 11 , wherein the panel has a thickness of from about 5-6 mm throughout.

14 . The thermoplastic vehicle body closure panel of claim 11 , wherein said part is selected from the group comprising an inner liftgate panel and a rear truck tailgate.

15 . The thermoplastic vehicle body closure panel of claim 11 , wherein said part includes at least an outer show surface of a virgin polymer material and inner microcellular structural core of a long glass fiber reinforced thermoplastic material.

16 . The thermoplastic vehicle body closure panel of claim 15 , wherein said reinforced thermoplastic material is a polyolefin which is from about 30% to about 40% filled with 12 mm glass fibers which are reduced to from about 1-4 mm length fibers during the injection process.

17 . A process for manufacture of a thermoplastic vehicle body closure panel comprising:
providing a mold having at least part thereof capable of forming a Class A surface and configured for injection of a supercritical fluid into predetermined class A areas of the molded liftgate inner panel; providing an injection moldable thermoplastic material; and injection molding the thermoplastic vehicle body closure panel structure from said thermoplastic material in a first step with injection of a combination of said supercritical fluid and a second thermoplastic material into said predetermined areas of said mold after the class A surface of the mold is pre-covered in thermoplastic material with the mold closed in a dimension of from about 2 to about 3 mm part thickness and thereafter releasing the pressure on the mold cavity and allowing controlled parallel expansion of the mold during the microcellular foam expansion to provide a final part thickness of from about 4 mm to 6 mm.

18 . The process for manufacture of thermoplastic vehicle body closure panel of claim 17 , wherein a sequential valve gate mold and a press having leveling on four corners of the mold for allowing parallel controlled mold expansion is used for the process.

19 . The process for manufacture of thermoplastic vehicle body closure panel of claim 18 , wherein a two shot nozzle is used.

20 . The process for manufacture of thermoplastic vehicle body closure panel of claim 19 , wherein virgin show surface thermoplastic is injected first at a first portion of the mold and said second thermoplastic material is injected at a separate location along with said supercritical fluid.

21 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 17 , wherein said thermoplastic is a virgin thermoplastic resin.

22 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 17 , wherein the part produced is greater than 3 mm thick at all areas of the part.

23 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 17 , wherein the part is produced to be from 4-6 mm thick.

24 . The process for manufacture of a thermoplastic vehicle body closure panel of claim 17 , further comprising molding a continuously molded structure including at least a first cosmetic area, a second structural area and a third attachment area, and wherein said second structural area and third attachment area are said predetermined areas for injection of said supercritical fluid and said second thermoplastic material.

Assignees

• Magna Int Inc

Inventors

• Birka Mark P

Classifications

• B29L2031/3005

  Body finishings · CPC title

• B29K2105/12

  of short lengths, e.g. chopped filaments, staple fibres or bristles · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title

• B32B2607/00

  Walls, panels · CPC title

• B60J5/107

  constructional details, e.g. about door frame, panels, materials used, reinforcements · CPC title