# US 10,870,240 B2 · Moulding material for composite panels

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- Number: US 10,870,240 B2
- Document ID: US10870240B2
- Status: Granted
- Kind: B2
- Application number: 15/556,493
- Filed: 2016-03-10
- Published: 2018-02-15
- Granted: 2020-12-22
- Earliest claimed: 2015-03-10
- Assignees: Gurit (UK) Ltd.
- Applicants: Gurit (UK) Ltd.
- Inventors: Daniel Thomas Jones
- Web page: https://patentgrep.com/patent/US10870240B2

## CPC

- B32B 7/09: by stitching, needling or sewing (by {mechanically connecting} fibrous layers {to another layer} B32B5/06)
- B29C 70/081: {Combinations of fibres of continuous or substantial length and short fibres}
- B29C 70/083: {Combinations of continuous fibres or fibrous profiled structures oriented in one direction and reinforcements forming a two dimensional structure, e.g. mats (B29D24/00, B29D99/001 take precedence)}
- B29C 70/48: and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM] {, e.g. by vacuum}
- B32B 3/00: Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B 3/26: characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids {(foam layer B32B5/18; layer of synthetic resin characterised by fillers that create voids or cavities B32B27/205); characterised by an apertured layer}
- B32B 3/266: {characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12}
- B32B 5/00: Layered products characterised by the non- homogeneity or physical structure {, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts}
- B32B 5/02: characterised by structural features of a {fibrous or filamentary} layer {(layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02)}
- B32B 5/022: {Non-woven fabric}
- B32B 5/024: {Woven fabric}
- B32B 5/06: characterised by a fibrous {or filamentary} layer {mechanically connected, e.g. by needling} to another layer, e.g. of fibres, of paper
- B32B 5/12: characterised by the relative arrangement of fibres or filaments of {different layers, e.g. the fibres or filaments being parallel or perpendicular to each other}
- B32B 5/16: characterised by features of a layer formed of particles, e.g. chips, powder {or granules (layer formed of natural mineral particles B32B19/00; layer being formed of wood fibres, chips or particles B32B21/02)}
- B32B 5/22: characterised by the presence of two or more layers which {are next to each other and are fibrous, filamentary, formed of particles or foamed (layer formed of natural mineral fibres or particles next to a foam layer B32B19/047, next to a layer made of particles B32B19/048, or next to a fibrous or filamentary layer B32B19/06; paper layer or cardboard layer next to a paper layer or cardboard layer B32B29/005, next to a foam layer B32B29/007, next to a fibrous or filamentary layer B32B29/02, or next to a particulate layer B32B29/04)}
- B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)}
- B32B 5/30: one layer {being formed of particles, e.g. chips,} granules, powder
- B32B 7/00: Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B 7/02: Physical, chemical or physicochemical properties
- B32B 27/06: as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08)}
- B32B 27/08: of synthetic resin
- B32B 27/12: next to a fibrous or filamentary layer
- B32B 27/18: characterised by the use of special additives
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/26: using curing agents
- B32B 27/28: comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42}
- B32B 27/38: comprising epoxy resins
- C08J 5/243: {using carbon fibres}
- C08J 5/249: {characterised by the additives used in the prepolymer mixture}
- B29K 2063/00: Use of {EP, i.e.} epoxy resins {or derivatives thereof}, as moulding material
- B29K 2105/0872: {Prepregs}
- B29K 2105/12: of short lengths, e.g. chopped filaments, staple fibres or bristles
- B29K 2307/04: Carbon
- B32B 2250/00: Layers arrangement
- B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
- B32B 2260/023: Two or more layers
- B32B 2260/046: Synthetic resin
- B32B 2262/00: Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B 2262/106: Carbon fibres, e.g. graphite fibres
- B32B 2264/00: Composition or properties of particles which form a particulate layer or are present as additives
- B32B 2264/10: Inorganic particles
- B32B 2264/101: Glass
- B32B 2264/102: Oxide or hydroxide
- B32B 2307/546: Flexural strength; Flexion stiffness
- B32B 2307/56: Damping, energy absorption
- B32B 2307/718: Weight, e.g. weight per square meter
- B32B 2307/726: Permeability to liquids, absorption
- B32B 2605/00: Vehicles
- B32B 2605/003: Interior finishings
- B32B 2605/08: Cars
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

The present invention describes a prepreg for the manufacture of fibre reinforced resin matrix composite materials, the prepreg comprising: a surface film comprising a thermosetting resin and a particulate filler material dispersed therein, and a fibrous layer on which the surface film is disposed, the fibrous layer comprising a plurality of non-woven carbon fibres which are substantially randomly oriented, wherein the fibrous layer has interstices between the carbon fibres dimensioned for absorbing at least a portion of the thermosetting resin during a resin infusion step and filtering at least a portion of the particulate filler material in the surface film to remain in the surface film during the resin infusion step.

## Claims

### Claim 1

A method for preparing a fibre reinforced resin matrix composite material, the method comprising the steps of:
(i) providing a prepreg comprising:
a surface film comprising a thermosetting resin and a particulate filler material dispersed therein; and
a fibrous layer on which the surface film is disposed, the fibrous layer comprising a plurality of non-woven carbon fibres which are substantially randomly oriented, wherein the fibrous layer has interstices between the carbon fibres dimensioned for absorbing at least a portion of the thermosetting resin during a resin infusion step and filtering at least a portion of the particulate filler material in the surface film to remain in the surface film during the resin infusion step;
(ii) providing a mould;
(iii) loading the prepreg into a cavity of the mould such that the surface film is located against a moulding surface of the mould; and
(iv) subjecting the prepreg to a moulding step, the moulding step comprising applying a vacuum to the cavity of the mould and applying a closure load to the mould to generate a pressure in the cavity of the mould to cause at least a portion of the thermosetting resin to infuse into the fibrous layer to impregnate the carbon fibres and to filter at least a portion of the particulate filler material in the surface film to remain in the surface film, the surface film forming a moulded surface of the fibre reinforced resin matrix composite material;
wherein the surface film in the prepreg has a thickness of from 150-600 microns and a particulate filler concentration of from 2 to 40 vol %, and wherein after the moulding step the surface film of the fibre reinforced resin matrix composite material has a thickness of from 25-400 microns and a particulate filler concentration of from 10 to 70 vol %.

### Claim 2 (depends on 1)

The method according to claim 1, wherein during the moulding step the fibrous layer has a loft such that when the fibrous layer is a subjected to a compressive load of 1 bar at 18-23° C. the thickness of the fibrous layer is reduced by at least 30%.

### Claim 3 (depends on 1)

The method according to claim 1, wherein during the moulding step the fibrous layer absorbs at least 25 vol % of the thermosetting resin.

### Claim 4 (depends on 1)

The method according to claim 1, wherein during the moulding step the fibrous layer filters at least 10 vol % of the particulate filler material in the surface film to remain in the surface film.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the fibrous layer in the prepreg comprises needle holes, and wherein the needle holes are at least partially filled with the particulate filler material during the moulding step.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the prepreg in step (i) comprises a plurality of the surface films and at least one of the fibrous layers to form a multilayer prepreg, wherein the at least one fibrous layer is sandwiched between opposing surface films, and wherein during the moulding step at least a portion of the thermosetting resin from each of the opposing surface films infuses into the at least one fibrous layer to impregnate the carbon fibres.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the prepreg in step (i) comprises at least two of the fibrous layers and further comprises at least one additional layer sandwiched between opposing fibrous layers.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the additional layer comprises a syntactic layer, wherein the syntactic layer comprises a resin and hollow microspheres dispersed therein.

### Claim 9 (depends on 8)

The method according to claim 8, wherein during the moulding step at least a portion of thermosetting resin from the syntactic layer infuses into each of the fibrous layers to impregnate the carbon fibres.

### Claim 10 (depends on 7)

The method according to claim 7, wherein the additional layer comprises a resin.

### Claim 11 (depends on 7)

The prepreg according to claim 7, wherein the additional layer comprises more than one unidirectional prepreg, wherein each unidirectional prepreg comprises fibres aligned unidirectionally, and wherein the fibre alignments of the more than one prepregs are staggered with respect to each other.

### Claim 12 (depends on 7)

The method according to claim 7, wherein the additional layer is a central layer of the composite material and the composite material layers are symmetrical about the central layer.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the moulding step is conducted at a pressure of from 6 to 50 bar.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the moulding step is conducted at a temperature of from 80 to 250° C.

### Claim 15 (depends on 1)

The method according to claim 1, wherein the fibrous layer comprises chopped and/or cut fibres.

### Claim 16 (depends on 1)

The method according to claim 1, wherein fibre reinforced resin matrix composite material is a vehicle body panel.

### Claim 17

A method for preparing a fibre reinforced resin matrix composite material, the method comprising the steps of:
(i) providing a prepreg, the prepreg comprising:
a surface film comprising a thermosetting resin and a particulate filler material dispersed therein, wherein the surface film has a thickness of from 150 to 600 microns, the surface film has a particulate filler material concentration of from 2 to 40 vol % based on the volume of the surface film, the particulate filler material comprises Talc, calcium carbonate, silica, alumino-silicate ash, chalk, clay minerals, marble dust, slate powder or silicon carbide, and the particulate filler material has an average particle size of from 5 to 30 microns; and
a fibrous layer on which the surface film is disposed, the fibrous layer comprising a plurality of non-woven carbon fibres which are substantially randomly oriented, wherein the fibrous layer comprises chopped and/or cut fibres;
wherein the fibrous layer has interstices between the carbon fibres dimensioned for absorbing at least a portion of the thermosetting resin during a resin infusion step and filtering at least a portion of the particulate filler material in the surface film to remain in the surface film during the resin infusion step;
(ii) providing a heated premould;
(iii) loading the prepreg into the premould;
(iv) subjecting the prepreg to a temperature of from 0 to 150° C. and/or a pressure of from 0.01 to 10 bar so as to increase rigidity of the prepreg and form a preform;
(v) providing a mould;
(vi) loading the preform into a cavity of the mould such that the surface film is located against a moulding surface of the mould; and
(vii) subjecting the preform to a moulding step, the moulding step comprising applying a vacuum to the cavity of the mould and applying a closure load to the mould to generate a pressure in the cavity of the mould to cause at least a portion of the thermosetting resin to infuse into the fibrous layer to impregnate the carbon fibres and to filter at least a portion of the particulate filler material in the surface film to remain in the surface film, the surface film forming a moulded surface of the fibre reinforced resin matrix composite material.

### Claim 18 (depends on 1)

The method according to claim 1, A method for preparing a fibre reinforced resin matrix composite material, the method comprising the steps of: (i) providing a prepreg comprising: a surface film comprising a thermosetting resin and a particulate filler material dispersed therein; and a fibrous layer on which the surface film is disposed, the fibrous layer comprising a plurality of non-woven carbon fibres which are substantially randomly oriented, wherein the fibrous layer has interstices between the carbon fibres dimensioned for absorbing at least a portion of the thermosetting resin during a resin infusion step and filtering at least a portion of the particulate filler material in the surface film to remain in the surface film during the resin infusion step; (ii) providing a mould; (iii) loading the prepreg into a cavity of the mould such that the surface film is located against a moulding surface of the mould; and (iv) subjecting the prepreg to a moulding step, the moulding step comprising applying a vacuum to the cavity of the mould and applying a closure load to the mould to generate a pressure in the cavity of the mould to cause at least a portion of the thermosetting resin to infuse into the fibrous layer to impregnate the carbon fibres and to filter at least a portion of the particulate filler material in the surface film to remain in the surface film, the surface film forming a moulded surface of the fibre reinforced resin matrix composite material wherein in the prepreg the surface film has a thickness of from 150 to 600 microns, the surface film has a particulate filler material concentration of from 2 to 40 vol % based on the volume of the surface film, the particulate filler material comprises Talc, calcium carbonate, silica, alumino-silicate ash, chalk, clay minerals, marble dust, slate powder or silicon carbide, and the particulate filler material has an average particle size of from 5 to 30 microns.