GB2297286A - Plastering deformable mouldings - Google Patents

Description

MOULDING Field of the invention The present invention relates to mouldings and to a method of moulding articles, the invention having particular application to vehicle bumpers, vehicle body panels and similar articles.

Background of the invention Bumpers and body panels for motor vehicle have been made of rigid plastics or glass fibre reinforced resin. Such moulded articles tend to fracture on minor impact and cannot readily be repaired.

Object of the invention The invention seeks to provide a method of moulding such articles to allow them to withstand minor impacts without fracturing or suffering damage while still being sufficiently rigid to perform their tasks as bumpers or body panels.

Summary of the invention According to a first aspect of the invention, there is provided a moulded article formed of a resin material that can be plastically deformed to conform to a curved surface, the resin material being fibre reinforced.

According to a second aspect of the invention, there is provided a method of moulding an article which comprises forming a mould, placing reinforcing fibres in the mould, coating the fibres with a resin material that is plastically deformable when cured and allowing the resin to cure.

The invention is a development of that disclosed in GB Patent Application No. 9315744.4 and differs from the latter application in that the resin is fibre reinforced instead of containing a filler. The latter Patent Application is concerned primarily with such items as architectural mouldings, dado rails, picture rails, skirting boards, architraves, panelling and ceiling coving that are permanently fixed to walls as a design feature. It is advantageous to form such articles from a material that permits plastic deformation as it allows the mouldings to be bent to conform to a curved surface, thereby facilitating their installation. However, such mouldings are permanently fixed when in use and, unlike bumpers, they do not need to have structural rigidity when not secured to a surface.

The present invention is based on the realisation that articles based on the same plastically deformable resin but reinforced with fibres will have considerable tensile strength allowing them to be used in such application as vehicle bumpers and body panels, but they will still be able to recover their normal shape after a minor impact, thereby avoiding the need for expensive repairs.

The moulded articles may suitably be formed from a resin material comprising a resin, cobalt accelerator and a catalyst for setting the resin.

The components of the material are preferably present in the ratios of 40 parts resin to 10 parts cobalt accelerator to 10 parts catalyst.

In the preferred embodiment of the invention, the resin comprises 28k diethylene glycol, 5% maleic anhydride, 12% phthalic anhydride, 18% tetrahydrophthalic anhydride and 37% styrene monomer.

This composition has been found to produce a moulding with the desired properties of flexibility and resistance to damage during use.

The cobalt accelerator mentioned herein is commonly used with thermosetting chemicals and is usually simply referred to as cobalt (after its main active ingredient). A suitable accelerator is AKZO Accelerator NL 49S, believed to comprise 1% cobalt in styrene.

The fibres used for reinforcement are preferably of glass and may be in the form of a non-woven chopped strand sheet or a woven cloth. The technique and fibre materials used to build up a laminated structure may be conventional and any material used in making convention GRP articles can be employed in the present invention, the difference residing in the use of a resin material that is plastically deformable even after it has been cured.

Detailed description of the invention In the manufacture of an article in the manner of the preferred embodiment of the invention, a mould of the desired shape is coated with a release agent as used in moulding a GRP article, a gel coating being applied to the mould, if necessary.

A resin mixture is prepared by mixing resin, cobalt accelerator and catalyst in the ratios of 40 parts resin, to 10 parts cobalt accelerator to 10 parts catalyst. The resin comprises 28% diethylene glycol, 5% maleic anhydride, 12% phthalic anhydride, 18% tetrahydro-phthalic anhydride and 37% styrene monomer. The cobalt accelerator is type NL 49S as supplied by AKZO Chemicals.

The reinforcement fibres, that may be of glass, carbon, Kevlar, Trevira, Spherecore or other material used in reinforcement of panels, are laid against the mould and covered with the prepared resin material. Further layers of fibres and resin are then applied in the same manner to build up a laminate. After the resin has been cured, the article is removed from the mould, this step being assisted by the initial application of a releasing agent.

Claims (7)

1. A method of moulding an article which comprises forming a mould, placing reinforcing fibres in the mould, coating the fibres with a resin material that is plastically deformable when cured and allowing the resin to cure.

2. A moulded article formed of a resin material that can be plastically deformed to conform to a curved surface, the resin material being fibre reinforced.

3. An article as claimed in claim 2, the article being formed from a resin material comprising a resin, cobalt accelerator and a catalyst for setting the resin.

4. An article as claimed in claim 3, wherein the components of the resin material are present in the ratios of 40 parts resin, to 10 parts cobalt accelerator to 10 parts catalyst.

5. An article as claimed in claim 3 or 4, wherein the resin comprises 28% diethylene glycol, 5% maleic anhydride, 12% phthalic anhydride, 18% tetrahydrophthalic anhydride and 37% styrene monomer.

6. An article as claimed in any of claims 3 to 5, wherein the cobalt accelerator comprise 1% cobalt in styrene.

7. An article as claimed in any of claims 2 to 6, wherein the reinforcement fibres are formed of glass.