Hybrid component part comprising a local stiffening composed of a two-stage-crosslinked polyurethane-based fibre composite material

Patent metadata

Field	Value
Publication number	US-10245789-B2
Application number	US-201615255247-A
Country	US
Kind code	B2
Filing date	Sep 2, 2016
Priority date	Sep 3, 2015
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

The invention relates to a hybrid component part comprising a local stiffening made of a two-stage-crosslinked polyurethane-based fiber composite material, more particularly to the production of such a hybrid component part. Said invention has for its object to specify a technology which makes it possible in cost-effective fashion to effect local stiffening of metal parts with a fiber composite material in order thus to obtain a hybrid component part. It is a fundamental concept of the process according to the present invention to use a particular polyurethane formulation which in a first crosslinking reaction can be converted into a thermoplastic polymer and later in a second crosslinking reaction is fully crosslinked to afford a thermoset matrix material. The thermoplastic polymer is characterized by a good adhesion to metal surfaces. The metal can be subjected to further forming with the attached thermoplastic material. The polyurethane is subsequently thermosettingly cured and achieves its final stiffness.

First claim

What is claimed is:

1. Process for producing a hybrid component part comprising the steps of:
a) providing a reactive composition at least comprising:
at least one hardener which is a uretdione having an NCO functionality of at least two,
at least one binder which is a polyol compound having an OH functionality of 3 to 6 and which comprises at least one polar functional group selected from an ester, carbonate, amide, urethane, urea, thioester or thiocarbonate functionality;

b) providing fibres;
c) coating the fibres with the reactive composition;
d) exposing at least the reactive composition to heat to perform a first crosslinking reaction in the course of which hardener and binder are converted into a thermoplastic polymer, thus embedding the fibres into the thermoplastic polymer;
e) providing a metallic main body or a semifinished precursor thereof;
f) placing the thermoplastic polymer comprising the fibres embedded therein onto a localized area of the main body/semifinished precursor thereof;
g) pressing the thermoplastic polymer onto the main body/semifinished precursor thereof so that the fibres adhere to the main body/semifinished precursor thereof via the thermoplastic polymer;
h) forming the semifinished precursor comprising the thermoplastic polymer adherent thereto to afford the metallic main body provided that only a semifinished precursor of the main body was provided in step e);
i) exposing at least the thermoplastic polymer to heat to perform a second crosslinking reaction in the course of which the thermoplastic polymer is converted to a thermoset polymer;
k) obtaining the hybrid component part comprising at least the metallic main body provided with at least one local stiffening composed of a fibre composite material, wherein the fibre composite material comprises a matrix formed from the thermoset polymer and the fibres embedded therein,
wherein the thermoplastic polymer comprising the fibres embedded therein is provided in layerwise fashion, in that the layers are compressed to afford a stack in the absence of the main body/the semifinished precursor thereof and in that the sequence of steps f) and q) is effected by placing and pressing the stack onto the main body/the semifinished precursor thereof.

2. Process according to claim 1 , characterized in that the second crosslinking reaction is performed at a temperature between 160° C. and 220° C.

3. Process according to claim 2 , characterized in that the main body is composed of a steel which in the course of performance of the second crosslinking reaction undergoes a change and/or rearrangement of its microstructure.

4. Process according to claim 1 , characterized in that the placing and/or the pressing of the thermoplastic polymer onto the main body/the semifinished precursor thereof is effected at a temperature of 20° C. to 25° C.

5. Process according to claim 2 with the proviso that a semifinished precursor of the main body is provided and formed into the main body with adherent thermoplastic polymer, characterized in that the forming of the semifinished precursor into the main body is effected at a temperature of 20° C. to 150° C., if necessary after heating of the semifinished precursor and/or by using a heated forming apparatus.

6. Process according to claim 1 , characterized in that the first crosslinking reaction is performed in the absence of the metallic main body/the semifinished precursor thereof.

7. Process according to claim 6 , characterized in that after performance of the first crosslinking reaction a period of one day to one year elapses before the second crosslinking reaction is performed and in that the thermoplastic polymer comprising the fibres embedded therein is stored and/or transported at temperatures between 15° C. and 30° C. over this period.

8. Process according to claim 1 , characterized in that as hardener uretdiones free from blocking agents are employed which are produced from at least one of the following substances:
isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12MDI), 2-methylpentane diisocyanate (MPDI), mixtures of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate (TMDI), and norbornane diisocyanate (NBDI).

9. Process according to claim 1 , characterized in that at least one polycaprolactone is employed as binder.

10. Process according to claim 1 , characterized in that as binder at least one polyester polyol is employed which has an OH number between 20 mg KOH/g and 500 mg KOH/g, an acid number of not more than 2 mg KOH/g and a molar mass between 100 g/mol and 5000 g/mol.

11. Process according to claim 1 , characterized in that the composition comprises at least one cobinder, wherein as cobinder epoxy resins are employed which are selected from the group comprising epoxy resins based on bisphenol A diglycidyl ether, epoxy resins based on bisphenol F diglycidyl ether and cycloaliphatic types, for example 3,4-epoxycyclohexylepoxyethane or 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

12. Process according to claim 11 , characterized in that the composition comprises a hardener corresponding to the cobinder which is selected from the group comprising the following substance classes: polycarboxylic acid, polycarboxylic anhydride, aliphatic polyamines, cycloaliphatic polyamines, polyetheramines, polymercaptans or polyamidoamines.

13. Process according to claim 1 , characterized in that the composition is free from substances that exhibit catalytic activity for the first and/or second crosslinking reaction.

14. Process according to claim 1 , characterized in that the composition is provided in a liquid solvent, wherein the constituents of the composition are dissolved and/or suspended and/or dispersed in the solvent so that the coating of the fibres with the composition is effected by impregnating the fibres with the solvent and in that the constituents dissolved/suspended/dispersed therein, and in that the solvent is at least partly evaporated from the fibres in the course of performance of the first crosslinking reaction, wherein the solvent is an ester or a ketone or a mixture comprising at least one ester and/or at least one ketone.

15. Process according to claim 1 , characterized in that the thermoplastic polymer comprising the fibres embedded therein is placed at the localized region of the main body/the semifinished precursor thereof without the use of an additional adhesive.

16. Hybrid component part comprising a metallic main body provided with at least one local stiffening made of a fibre composite material, wherein the fibre composite material comprises a polyurethane-based thermoset matrix and fibres embedded therein, characterized in that the hybrid component part has been produced by a process according to claim 1 .

17. Process for producing a hybrid component part comprising the steps of:
a) providing a reactive composition at least comprising:
at least one hardener which is a uretdione having an NCO functionality of at least two,
at least one binder which is a polyol compound having an OH functionality of 3 to 6 and which comprises at least one polar functional group selected from an ester, carbonate, amide, urethane, urea, thioester or thiocarbonate functionality;

b) providing fibres;
c) coating the fibres with the reactive composition;
d) exposing at least the reactive composition to heat to perform a first crosslinking reaction in the course of which hardener and binder are converted into a thermoplastic polymer, thus embedding the fibres in

Assignees

• Evonik Degussa Gmbh

Inventors

• Cron Christina
• Schmidt Marina-Elena
• Gutmann Tobias
• Stapperfenne Uwe
• Reemers Sandra
• Ickert Leif

Classifications

• C08G18/42

  Polycondensates having carboxylic or carbonic ester groups in the main chain · CPC title

• C08G59/42

  Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof · CPC title

• C08G18/798

  containing urethdione groups · CPC title

• B29C70/028

  and with one or more layers of non-plastics material or non-specified material, e.g. supports · CPC title

• B29K2105/243

  Partially cured · CPC title