Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1990-04-25
1992-06-02
Lesmes, George F.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428373, 428253, 428902, 66190, 66202, B32B 700
Patent
active
051185695
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a reinforcement sheet having a novel structure. More particularly, the present invention relates to a reinforcement sheet having a novel structure, and useful for preparing, by a thermal shaping (forming) method, a composite material comprising a thermoplastic polymer as a matrix and high-strength high-modulus filament yarns as a reinforcing material.
BACKGROUND ART
For example, a unidirectional cord fabric (see U.S. Pat. No. 3,859,158) is known as the conventional reinforcement sheet, but this fabric is defective in that, since reinforcing yarns arranged in the warp direction are bent by the pressure thereon of wefts, the capacity of the reinforcing yarns is weakened. Moreover, the fabric is defective in that the reinforcing yarns are not tightly bonded to wefts, crossing points between the reinforcing yarns and wefts are liable to shift, and the handling and processability thereof are poor. Moreover, this fabric has a serious defect in that, since the reinforcing yarns are first bonded to one another by a resin, the fabric has no pliability and the fitting of the fabric in a mold at the molding step is difficult.
As the means for overcoming these defects, there has been proposed a soft reinforcement sheet (fabric) comprising a reinforcing thermoplastic yarn (constituting a matrix after thermal shaping) and a reinforcing yarn (see U.S. Pat. No. 3,620,892, British Patent No. 1,228,573 and British Patent No. 1,226,409). Nevertheless, even according to this proposal, since the matrix yarns and reinforcing yarns are woven into a fabric, the reinforcing yarns in the fabric structure are still bent, and the defect that the capacity of the reinforcing yarns is weakened is not overcome.
Japanese Unexamined Patent Publication No. 60-28543 discloses a method in which polyether ether ketone fiber (matrix fiber) yarns and reinforcing fiber yarns are woven or knitted into a woven fabric, knitted fabric or mat. This prior art technique, for example, in connection with a knitted fabric, teaches only a warp-knitted fabric obtained by arranging matrix fiber yarns and reinforcing fiber yarns, alternately one by one, and knitting them with auxiliary yarns such as polyether ether ketone fiber yarns or glass fiber yarns.
Also, in this case, the reinforcing yarns in the structure of the warp-knitted fabric are bent, and therefore, the above problem is not solved.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a reinforcement sheet having a good pliability and an improved handling and formability, and useful for producing a shaped article therefrom in which the maximum capacity of reinforcing yarns is obtained.
Another object of the present invention is to provide a reinforcement sheet comprising reinforcing yarns kept in the linear state without being bent, in which the reinforcing yarns are not exposed to the outer side of the obtained shaped article.
The reinforcement sheet of the present invention has a knitting structure and is characterized in that reinforcing yarns are held in the linear state without being bent in a matrix knitting structure composed of matrix yarns.
More specifically, the reinforcement sheet of the present invention has a knitting structure comprising a plurality of reinforcing yarns 5, a plurality of matrix yarns 9 and a plurality of heat-fusion-bondable yarns 6a-6c, wherein the reinforcing yarns are held in the linear state without being bent, at least one reinforcing yarn is doubled, mixed, entangled or double-twisted with at least one heat-fusion-bondable yarn or arranged between two heat-fusion-bondable yarns 6 to form a composite yarn, the composite yarns are arranged in parallel to and spaced from one another, and the matrix yarns are knitted around the composite yarns to cover the reinforcing yarns, whereby a plurality of repeating knitting units P, which are parallel to one another, are formed and the knitting units are connected to one another to form a continuous matrix knitting structure, wherein the total
REFERENCES:
patent: 4183993 (1980-01-01), Benstead et al.
English translation of JP 48-50055, pp. 1-8.
English translation of JP 58-8162, pp. 1-9.
English translation of JP 58-8161, pp. 1-8.
Hosoi Mitsuo
Kiyohara Nobutaka
Kuroda Toshimasa
Oka Takashige
Sato Akihiro
Gunze Limited
Lesmes George F.
Pawlikowski Beverly A.
Teijin Limited
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