Moulding material
A preform moulding material includes two individual unidirectional reinforcement layers of a fibrous reinforcement material and a resin material between adjacent ones of the fibrous reinforcement layers. The resin material is a matrix resin material that partially impregnates and conjoins the fibrous reinforcement layers. Each of the fibrous reinforcement layers includes a fabric that is skewed relative to a lengthwise direction of the preform moulding material and includes a weft of unidirectional fibrous reinforcement material disposed at an angle relative to the lengthwise direction and a warp of fibres in the lengthwise direction. The orientation of the unidirectional fibrous reinforcement material of one of the reinforcement layers differs from the orientation of the unidirectional fibrous reinforcement material of the other reinforcement layer such that the preform moulding material is bi-axial prepreg.
1. A preform moulding material comprising:
two individual unidirectional reinforcement layers of a fibrous reinforcement material; and
a resin material between adjacent ones of the fibrous reinforcement layers;
wherein the resin material is a matrix resin material, whereby the preform moulding material forms a prepreg;
wherein the matrix resin material between the fibrous reinforcement layers partially impregnates and conjoins the fibrous reinforcement layers, thereby obviating the need in the prepreg for an additional bonding means to join the individual fibrous reinforcement layers;
wherein one of the fibrous reinforcement layers includes a fabric that is skewed relative to a lengthwise direction of the preform moulding material and including a weft of unidirectional fibrous reinforcement material disposed at an angle relative to the lengthwise direction and a warp of fibres in the lengthwise direction; and
wherein the other of the fibrous reinforcement layers includes a fabric that is skewed relative to the lengthwise direction of the preform moulding material and including a weft of unidirectional fibrous reinforcement material at an angle relative to the lengthwise direction and a warp of fibres in the lengthwise direction;
wherein the orientation of the unidirectional fibrous reinforcement material of one of the reinforcement layers differs from the orientation of the unidirectional fibrous reinforcement material of the other reinforcement layer;
whereby said preform moulding material is bi-axial prepreg.
2. A preform moulding material according to claim 1 wherein the two individual layers of fibrous reinforcement material are pressed into the matrix resin material therebetween to directly partially impregnate the fibrous reinforcement layers.
3. A preform moulding material according to claim 1 wherein the orientation or weft of the fibres in one unidirectional fibrous reinforcement layer is at an angle of −45 degrees relative to the lengthwise direction, and wherein the orientation or weft of the fibres of the other unidirectional fibrous reinforcement layer is at an angle of +45 degrees relative to the lengthwise direction.
4. A preform moulding material according to claim 1 wherein the matrix resin material impregnated into the fibrous reinforcement layers retains the orientation of the fibrous reinforcement material of the reinforcement layers.