Methods for increasing impact resistance of reinforced polymeric composites

Patent metadata

Field	Value
Publication number	US-9744699-B2
Application number	US-201414471829-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Aug 28, 2014
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Methods of compression molding polymeric parts for improved impact resistance are provided. The components are particularly suitable for use in a vehicle or an automobile. The compression molded polymeric component comprises a central region or core comprising integrally formed foam, e.g., a foam core, that can sustain high impact load and does not lead to visible surface cracking or material cracking. The polymeric component may be a reinforced plastic composite (FRP). Such methods can produce lightweight, impact resistant, FRP components that may be used in various structural applications, including in automobiles.

First claim

What is claimed is:

1. A method of compression molding a polymeric component having improved impact resistance, the method comprising:
applying a foaming agent to a first surface of a first blank comprising a first polymeric material;
contacting a second surface of a second blank comprising a second polymeric material with the foaming agent to form an assembly, wherein the foaming agent is sandwiched between the first blank and the second blank in the assembly;
disposing the assembly in a mold cavity of a compression mold; and
compression molding the assembly by applying heat and pressure to form a compression molded consolidated polymeric component comprising a first polymeric layer, an intermediate foam layer, and a second polymeric layer,
wherein the first polymeric material of the first blank and the second polymeric material of the second blank comprise a thermoplastic resin, and the foaming agent has an optimal gas yield temperature (T A max ) and the thermoplastic resin has a maximum melting temperature (T m ) having a relationship of T m −50° C.≦T A max <T m +50° C.

2. The method of claim 1 , wherein the first polymeric material of the first blank and the second polymeric material of the second blank are both reinforced composites each comprising a polymer and a reinforcement material.

3. The method of claim 2 , wherein the reinforcement material is selected from the group consisting of: a plurality of fibers, whiskers, platelets, particles, and combinations thereof.

4. The method of claim 1 , wherein the heat applied during compression molding has a temperature (T molding ), having the following relationships: T m ≦T molding <T m +50° C. and T molding ≦T A max .

5. The method of claim 1 , further comprising preheating the first blank and the second blank prior to or during the applying of the foaming agent.

6. The method of claim 1 , wherein the compression molded consolidated polymeric component has a Young's modulus (E) of greater than or equal to about 10 GPa to less than or equal to about 30 GPa.

7. The method of claim 1 , wherein the pressure applied during compression molding is greater than or equal to about 6 MPa and less than or equal to about 15 MPa.

8. A method of compression molding a polymeric component having improved impact resistance, the method comprising:
applying a foaming agent to a first surface of a first preheated blank comprising a first polymeric material;
contacting a second surface of a second preheated blank comprising a second polymeric material with the foaming agent to form an assembly, wherein the foaming agent is sandwiched between the first preheated blank and the second preheated blank in the assembly;
disposing the assembly in a mold cavity of a compression mold; and
compression molding the assembly by applying heat and pressure to form a compression molded consolidated polymeric component comprising a first polymeric layer, an intermediate foam layer, and a second polymeric layer, wherein the pressure applied during compression molding is greater than or equal to about 6 MPa and less than or equal to about 15 MPa.

9. The method of claim 8 , wherein the first polymeric material of the first blank and the second polymeric material of the second blank comprise a thermoplastic resin.

10. The method of claim 9 , wherein the foaming agent has an optimal gas yield temperature (T A max ) and the thermoplastic resin has a maximum melting temperature (T m ) having a relationship of T m −50° C.≦T A max <T m +50° C.

11. The method of claim 9 , further comprising preheating the first preheated blank to a first temperature (T preheat ), wherein the foaming agent has an optimal gas yield temperature (T A max ), the thermoplastic resin has a maximum melting temperature (T m ) and a glass transition temperature (T g ), and the heat applied during compression molding has a second temperature (T molding ) having the following relationships: T m <T preheat <T m +50° C. with T A max ≦T preheat and where T g ≦T molding <T m .

12. The method of claim 8 , wherein the first polymeric material of the first preheated blank and the second polymeric material of the second preheated blank are both reinforced composites each comprising a polymer and a reinforcement material.

13. The method of claim 8 , wherein the compression molded consolidated polymeric component has a Young's modulus (E) of greater than or equal to about 10 GPa to less than or equal to about 30 GPa.

14. The method of claim 8 , further comprising preheating the first preheated blank to a temperature that is greater than or equal to about a melting temperature (T m ) of the first polymeric material prior to applying the foaming agent, or preheating the second preheated blank to a temperature that is greater than or equal to about a melting temperature (T m ) of the second polymeric material prior to contacting the second surface of the second preheated blank with the foaming agent, or preheating the first preheated blank to a temperature that is greater than or equal to about a melting temperature (T m ) of the first polymeric material prior to applying the foaming agent and preheating the second preheated blank to a temperature that is greater than or equal to about a melting temperature (T m ) of the second polymeric material prior to contacting the second surface of the second preheated blank with the foaming agent.

15. A method of compression molding a polymeric structural component having improved impact resistance, the method comprising:
applying a foaming agent to a first surface of a first blank comprising a first polymer composite material;
contacting a second surface of a second blank comprising a second polymer composite material with the foaming agent to form an assembly, wherein the foaming agent is sandwiched between the first blank and the second blank in the assembly;
disposing the assembly in a mold cavity of a compression mold; and
compression molding the assembly by applying heat and pressure to form a compression molded consolidated polymeric structural component comprising a first composite layer, an intermediate foam layer, and a second composite layer, wherein the compression molded consolidated polymeric structural component has a Young's modulus (E) of greater than or equal to about 10 GPa to less than or equal to about 30 GPa.

16. The method of claim 15 , wherein the polymeric structural component is for a vehicle and the compression molded consolidated polymeric structural component is selected from the group consisting of: a hood, an underbody shield, a structural panel, an interior floor, a floor pan, a roof, an exterior surface, a fender, a scoop, a spoiler, a storage area, a glove box, a console box, a gas tank protection shield, a trunk, a trunk floor, a truck bed, and combinations thereof.

17. The method of claim 15 , wherein the pressure applied during compression molding is greater than or equal to about 6 MPa and less than or equal to about 15 MPa.

18. The method of claim 8 , wherein the first polymeric material and the second polymeric material comprise a thermoset resin and the foaming agent has an optimal gas yield temperature (T A max ), the thermoset resin has a curing temperature (T c ), and the heat applied during compression molding has a temperature (T molding ), having the following relationships: T c −10° C.≦T molding <T c +10° C. and T molding ≦T A max .

19. The method of claim 18 , further having the relationship of T c −50° C.≦T A max <T c +50° C.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Rousseau Ingrid A

Classifications

• B29C43/203 Primary

  Making multilayered articles · CPC title

• B29C44/1228

  Joining preformed parts by the expanding material · CPC title

• B29K2105/253

  Preform · CPC title

• B29K2307/04

  Carbon · CPC title

• B29C43/18

  incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles {(B29C43/206 takes precedence)} · CPC title