Process for Preparing Moulded Articles from Fibre-Reinforced Composite Materials - I

Patent metadata

Field	Value
Publication number	US-2016346958-A1
Application number	US-201615164366-A
Country	US
Kind code	A1
Filing date	May 25, 2016
Priority date	May 29, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

The present invention relates to low or zero-tack composite materials such as pre-pregs and their use in automated manufacturing, particularly robotic pick and place. The present invention further relates to an automated process for preparing an article, particularly a moulded article, from a fibre-reinforced composition material.
The moulded articles prepared by the process described herein are particularly suitable as components for transport applications, and particularly the automotive industry. The automotive components prepared by the present invention are particularly suitable as mid- or high-volume automotive parts, in which cost and speed of production are paramount. The present invention provides a process in which the cutting and handling of pre-preg materials is greatly simplified, providing advantages of efficiency and economy. The lay-up time according to the present invention is significantly reduced, allowing a reduction in the unit cost per component and/or allowing the high volume of component production desired in the automotive industry.

First claim

1 . An automated process for preparing a moulded article from a plurality of pre-pregs comprising the steps of:
(a) providing a mould; (b) disposing a laminar pre-preg into or onto said mould by an automated conveying member which applies a prehensile force to said pre-preg to convey said pre-preg from a starting position to a finishing position in or on said mould; (c) repeating step (b) at least once to dispose one or more further pre-pregs into or onto said mould; wherein said laminar pre-preg is a fibre-reinforced curable composite material, wherein said pre-preg comprises a core layer having a first surface and a second surface and further comprises a surface layer disposed directly on at least one surface of said core layer, wherein said core layer comprises one or more layer(s) of reinforcing fibres impregnated with a first curable resin, and wherein said surface layer comprises a second curable resin; and wherein the prehensile force is applied by said automated conveying member directly to the external surface of said surface layer of said pre-preg.

2 . The automated process of claim 1 wherein said prehensile force is selected from one or more of vacuum, magneto-adhesion and electro-adhesion, and preferably said prehensile force is a vacuum force.

3 . The automated process of claim 2 wherein said automated conveying member comprises an astrictive end effector to convey said prepreg from said starting position to said finishing position in or on said mould, optionally wherein said pre-preg is conveyed from said starting position to an intermediate position between said starting and finishing positions, wherein said intermediate position is a stacking position where said pre-preg is stacked or wherein said intermediate position is a position where said pre-preg is deposited in or on a release film or lay-up mould or mould loading device, and wherein said pre-preg is then conveyed from the intermediate position to said finishing position in or on said mould.

4 . The automated process of claim 3 which is conducted in an environment at ambient temperature or above.

5 . The automated process of claim 4 wherein said process further comprises the step of thermally curing said plurality of pre-pregs to form the moulded article, preferably wherein thermal curing is effected while the pre-pregs are compressed in a mould cavity, preferably an isothermally heated mould cavity and wherein thermal curing is conducted at a cure temperature of greater than 120° C., preferably in the range of from about 130° C. to about 150° C., and preferably wherein the plurality of pre-pregs is held at said cure temperature for a duration of no more 10 minutes.

6 . The automated process of claim 5 wherein the surface layer remains part of the fibre-reinforced composite material during and after curing.

7 . The automated process of claim 6 wherein the pre-preg is not associated with a protective removable interleave disposed on an external surface of the pre-preg and wherein the automated process does not comprise a step of removing said protective removable interleave.

8 . The automated process of claim 1 wherein the first curable resin comprises one or more curable thermosetting resin(s) selected from the group consisting of epoxy resins, bismaleimides, vinyl ester resins, cyanate ester resins, isocyanate-modified epoxy resins, phenolic resins, benzoxazine, formaldehyde condensate resins, polyesters, acrylics, and combinations thereof; preferably epoxy resins and the second curable resin comprises one or more curable thermosetting resin(s) selected from the group consisting of epoxy resins, bismaleimides, vinyl ester resins, cyanate ester resins, isocyanate-modified epoxy resins, phenolic resins, benzoxazine, formaldehyde condensate resins, polyesters, acrylics, and combinations thereof; preferably epoxy resins.

9 . The automated process of claim 1 wherein the first and second curable resins are independently selected from the group consisting of mono-functional, di-functional, and multi-functional epoxy resins, and mixtures thereof, and preferably the first and second curable resins are independently selected from curable resins which comprise one or more difunctional epoxy resin(s) optionally in combination with one or more multi-functional epoxy resin(s) and wherein said difunctional epoxy resins are selected from diglycidyl ether of bisphenol F (DGEBF), diglycidyl ether of bisphenol A (DGEBA), diglycidyl dihydroxy naphthalene, or any combination thereof; and wherein said multi-functional epoxy resins are selected from resin based on phenol and cresol epoxy novolacs, glycidyl ethers of phenol-aldehyde adducts, aromatic epoxy resins, aliphatic triglycidyl ethers, dialiphatic triglycidyl ethers, aliphatic polyglycidyl ethers, epoxidised olefins, triglycidyl aminophenols, aromatic glycidyl amines, heterocyclic glycidyl imidines and amides, glycidyl ethers, fluorinated epoxy resins, N,N,N′,N′-tetraglycidyl diamino diphenylmethane (TGDDM) and N,N,N′,N′-tetraglycidyl-m-xylenediamine, or any combination thereof.

10 . The automated process of claim 9 wherein the first and second curable resins are independently selected from curable resins which comprise:
(i) a first difunctional epoxy resin component, preferably selected from bisphenol A epoxy resins, and preferably DGEBA; and/or
(ii) a second difunctional epoxy resin component, preferably selected from bisphenol F epoxy resins, and preferably DGEBF;
optionally in combination with one or more of the epoxy resin(s) selected from:
(iii) an epoxy phenol novolac (EPN) resin;
(iv) an epoxy cresol novolac (ECN) resin;
(v) a trifunctional epoxy resin, preferably triglycidyl aminophenol, preferably triglycidyl para-aminophenol (TGPAP); and
(vi) a tetrafunctional epoxy resin, preferably tetraglycidyl diamino diphenyl methane (TGDDM).

11 . The automated process of claim 1 wherein the second curable resin exhibits a viscosity at 21° C. of at least 500,000 Pa·s, preferably at least 1,000,000 Pa·s, preferably at least 5,000,000 Pa·s, and/or an uncured Tg of at least 8° C., preferably from about 12 to 30° C. and wherein the first curable resin exhibits a viscosity at 21° C. of less than 500,000 Pa·s, preferably no more than 300,000 Pa·s, preferably no more than 100,000 Pa·s and/or an uncured Tg of less than 8° C., preferably no more than 6° C., preferably no more than 3° C.

12 . The automated process of claim 1 wherein the first curable resin exhibits a cure conversion of at least 90%, preferably at least 95%, preferably at least 98%, when cured at a temperature in the range of from 130° C. to 150° C. for a period of no more than 10 minutes, preferably for a period of no more than 5 minutes.

13 . The automated process of claim 6 wherein a surface layer is disposed on both surfaces of said core layer and the surface layer exhibits an areal weight of from about 5 to about 100 g/m 2 , preferably from about 20 to about 60 g/m 2 , more preferably about 25 to 50 g/m 2 , and/or wherein the thickness of the surface layer is no more than about 85 μm.

14 . The automated process of claim 1 wherein the core layer exhibits an areal weight of from about 200 to about 1500 g/m 2 , preferably from about 600 to about 1100 g/m 2 , and/or wherein the thickness of the core layer is no more than 1000 μm, preferably at least about 130 μm, preferably from about 250 μm to about 500 μm.

15 . The automated process of claim 1 wherein the pre-preg surface prior to curing has tack at ambient temperature such that, after a 100×100 mm sample of the pre-preg has been retained for 60 seconds by a silicone suction cu

Assignees

• Cytec Ind Inc

Inventors

• Steele Mark Raymond
• Gibbs Andrew Steven

Classifications

• B29C70/541

  Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement (positioning inserts in moulds B29C33/12; lay-up on a mould B29C70/30) · CPC title

• B29K2105/0872

  Prepregs · CPC title

• B29K2105/0094

  having particular viscosity · CPC title

• B29B11/16 Primary

  comprising fillers or reinforcement {(non-woven fabrics per se D04H1/00, D04H3/00)} · CPC title

• B29K2995/0063

  Density · CPC title