US-12624175-B2 - Reinforcement material for composite laminate

US12624175B2US 12624175 B2US12624175 B2US 12624175B2US-12624175-B2

Abstract

A woven fabric prepreg for constructing a composite laminate comprises two sheets of fabric woven from tows of fibres, impregnated with a polymer matrix and adhered together. Each sheet is woven in a satin weave such that the tows create long floats on at least one side of the sheet. The sheets are positioned face-to-face with the long floats parallel, such that the tows pack together and the space between the sheets is minimised.

Inventors

Robert Burnell

Assignees

PRF Composite Holdings Limited

Dates

Publication Date: 20260512
Application Date: 20230410
Priority Date: 20220411

Claims (15)

1 . A method of manufacturing a woven multi-layer fabric prepreg for use in constructing a composite laminate, comprising the steps of: providing two sheets of woven fabric having tows of fibres in a satin weave, such that said tows create long floats on each side of each sheet, each sheet being elongate and having a longitudinal direction; impregnating each sheet of fabric with a polymer matrix, wherein only a face of one of said sheets is impregnated with the polymer matrix and only a back of the other of said sheets is impregnated with the polymer matrix, the face having long floats aligned with the longitudinal direction and the back having long floats aligned in a direction orthogonal to the longitudinal direction; placing the sheets together in any one of: face-to-face, so that there is only a single layer of polymer matrix between the faces, and back-to-back, so that there is only a single layer of polymer matrix between the backs, with the long floats parallel, such that the tows pack together and enclosed free space between the sheets is minimised, and so that the longitudinal directions are aligned; and adhering said sheets together to form the woven multi-layer fabric prepreg.
2 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , further comprising cutting the woven multi-layer fabric prepreg into pieces.
3 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 2 , wherein the woven multi-layer fabric prepreg is elongate and said cutting occurs in a direction transverse to a longitudinal direction of the woven multi-layer fabric prepreg.
4 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein at least one of the two sheets of fabric is provided on a roll.
5 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein at least one of the two sheets of fabric is greater than 100 m long.
6 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein each sheet has a fabric weight of over 500 gsm so that the woven multi-layer fabric prepreg has a fabric weight of over 1000 gsm.
7 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein each sheet has a fabric weight of between 500 gsm and 525 gsm so that the woven multi-layer fabric prepreg has a fabric weight of between 1000 and 1050 gsm.
8 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein the satin weave is any one of a four, five, and eight harness satin weave.
9 . A method of manufacturing a composite laminate, comprising the steps of: obtaining a pattern or a mould; obtaining a first woven multi-layer fabric prepreg manufactured using the method of claim 1 ; creating a laminate by placing a plurality of layers of said first fabric prepreg onto said pattern or into said mould; and curing said laminate using heat.
10 . The method of manufacturing a composite laminate according to claim 9 , further comprising the step of: obtaining a second woven fabric prepreg, said second fabric prepreg having a lower fabric weight than said first fabric prepreg; and wherein said step of creating a laminate further comprises the step of placing a layer of said second fabric prepreg before said layers of said first fabric prepreg.
11 . The method of manufacturing a composite laminate according to claim 10 , wherein a single debulking occurs after placement of the second fabric prepreg and one layer of the first fabric prepreg.
12 . The method of manufacturing a composite laminate according to claim 10 , further comprising the step of placing a further layer of said second fabric prepreg after said layers of said first fabric prepreg.
13 . The method of manufacturing a composite laminate according to claim 9 wherein there are an odd number of layers of the first fabric prepreg.
14 . The method of manufacturing a composite laminate according to claim 13 wherein there are five layers of the first fabric prepreg.
15 . The method of manufacturing a composite laminate according to claim 9 , wherein said layers of said first fabric prepreg are placed such that the tows of adjacent layers are neither parallel nor orthogonal to each other.

Description

TECHNICAL FIELD The present invention relates to a woven multi-layer fabric prepreg for use in constructing a composite laminate, a method of manufacturing a woven multi-layer fabric prepreg, and a method of manufacturing a composite laminate. BACKGROUND OF THE INVENTION Composite laminates of reinforced materials are often used to make strong yet lightweight components. Such components are used in many industries, such as the automotive, aerospace and electricity generation industries. Additionally, they may be used for personal items such as body armour or sporting goods. A reinforcement material is typically a mix of fibres and a polymer matrix. Common fibres are carbon fibre, glass fibre, or natural fibres such as flax and hemp. The polymer matrix is often a resin, such as epoxy, phenolic, bismaleimide, or cyanate ester. The reinforcement fibres are commonly either laid uni-directionally or woven, depending upon the desired result. A component that requires strength in all directions is often made using woven reinforcement material. One method of creating a composite laminate is by layering sheets of reinforcement material over a pattern or in a mould before curing. The polymer matrix may be added separately, but for the best results the reinforcement material is pre-impregnated with the polymer matrix. Sheets of pre-impregnated material are referred to as prepregs. Creating a composite laminate is time-consuming, as each layer of prepreg must be cut to size and shape before being laid on, ensuring intimate contact with the surface of the pattern or mould. Using a thicker prepreg requires fewer layers to be used, which therefore speeds the process up. However, it is difficult to impregnate thicker fabric sufficiently, and typically there will be a lot of dry fibre in the material, and therefore a lot of enclosed free space in which air can be trapped. The air needs to be removed regularly using a debulking process carried out under vacuum. Thus, using a thicker fabric does not necessarily reduce the time to create a composite laminate. In addition, thicker fabrics can be difficult to work with for complex forms, as they are stiffer and have less drape. BRIEF SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a method of manufacturing a woven multi-layer fabric prepreg for use in constructing a composite laminate, comprising the steps of: providing two sheets of woven fabric using tows of fibres in a satin weave, such that said tows create long floats on each side of each sheet, each sheet being elongate and having a longitudinal direction; impregnating each sheet of fabric with a polymer matrix; placing the sheets together face-to-face or back-to-back with the long floats parallel, such that the tows pack together and enclosed free space between the sheets is minimised, and so that the longitudinal directions are aligned; and adhering said sheets together to form the woven multi-layer fabric prepreg. By providing an elongate sheet, the multi-layer fabric prepreg can be constructed in a quicker and more cost-effective manner. This is compared to if square sheets of fabric are used, with one sheet being rotated to provide the parallel long float formation. Since the enclosed free space between the sheets is minimised by the long floats nesting, the requirement for debulking is reduced or eliminated. The more delicate satin weaves are chosen for their improved drapability whilst maintaining good, improved handling of the fabric. A fabric prepreg formed in such a manner is balanced, which allows for it to be used in a straightforward manner. The face of the sheet may be referred to as the warp side, and the back of the sheet may be referred to as the weft side. The face or warp side has long floats aligned with the longitudinal direction, and the back or weft side has long floats aligned in an orthogonal direction. It will be appreciated the term of “face-to-face” and “back-to-back” may equate to “warp-side-to-warp-side” and “weft-side-to-weft-side” respectively. Preferably, the method may further comprise cutting the woven multi-layer fabric prepreg into pieces. Advantageously, the woven multi-layer fabric prepreg may be elongate and said cutting may occur in a direction transverse to a longitudinal direction of the woven multi-layer fabric prepreg. Since the sheets are long, the resulting multi-layer fabric prepreg is also long, and therefore the multi-layer fabric prepreg may be cut into pieces or strips to allow easier use thereof. The prepreg is preferably cut automatically and continuously on a conveyorised computer numerical control (CNC) machine. Before cutting, it will be appreciated that the fabric prepreg may be wound onto a roll, so as to allow for more convenient transportation. Advantageously, at least one of the two sheets of fabric may be provided on a roll. Both sheets are preferably provided on separate rolls. This allows for more convenient st