Plastic and nonmetallic article shaping or treating: processes – Direct application of electrical or wave energy to work – Using sonic – supersonic – or ultrasonic energy
Reexamination Certificate
2001-10-12
2004-06-01
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Direct application of electrical or wave energy to work
Using sonic, supersonic, or ultrasonic energy
C028S282000, C264S136000, C264S137000, C264S345000
Reexamination Certificate
active
06743392
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an apparatus for producing a spread fiber bundle and a method for producing a spread fiber bundle using the production apparatus, and further a method for producing a prepreg by impregnating a resin into a spread fiber bundle obtained by the production method.
BACKGROUND ART
Prepregs are widely used as intermediate base materials to be molded into aircraft materials, building materials, general industrial materials and sports and leisure articles. A prepreg is produced by a method of paralleling a plurality of fiber bundles, each consisting of a plurality of filaments, in the form of a sheet, thinly and uniformly spreading the plural filaments of the respective fiber bundles in a direction across the parallel direction (transverse direction), and impregnating spaces between the spread filaments with a matrix resin.
Applications of prepregs have been diversified. Prepregs having thin and small irregularity in thickness are demanded. To product such a prepreg, a technique for widely and thinly spreading a fiber bundle without degrading the bundle is necessary.
For spreading a fiber bundle, JP-56-43435-A teaches a method of spreading a fiber bundle, in which the fiber bundle is transferred in contact with plural rollers while being bent around the rollers, and is brought into pressure contact with a cylindrical body vibrating in the axial direction during such transfer operation. YP-61-275438-A discloses a method of spreading a fiber bundle, in which the fiber bundle is transferred in contact with a reciprocating body or rotating body, while being vibrated in the vertical direction, and furthermore brought into pressure contact with a body having a curved surface. JP-7-268754-A proposes a method of spreading a fiber bundle, in which the fiber bundle is transferred in contact with a group of rollers including an eccentrically rotating body, to be spread by means of the eccentrically rotating body.
However, in these spreading methods, the fiber bundle is brought into strong pressure contact with a spreading body The fiber bundle receives a strong abrasive force from the surface of the spreading body, and the abrasion causes several filaments composing the fiber bundle to be broken, thereby generating fuzz in the fiber bundle. In the worst case, the fiber bundle is cut off. Especially to produce a thin prepreg, widely spread thin fiber bundles are needed. In the case where such fiber bundle is produced by any one of the conventional methods, the fiber bundle must be more strongly pressed against the spreading body. In this case, the generation of fuzz in the fiber bundle or the breaking of the fiber bundle becomes a more serious problem.
Such problem becomes especially serious if the fiber bundle is composed of filaments having a high elastic modulus or if the fiber bundle transfer speed is higher. The prepreg produced by using such fiber bundles are low in grade.
To solve such problem, it is proposed to decrease the friction coefficient of the spreading body used for spreading the fiber bundle or to use ultrasonic vibration, but the problem is not sufficiently solved.
It is an object of the invention to provide an apparatus for producing a spread fiber bundle that allows a fiber bundle to be stably and efficiently spread even if the fiber bundle to be spread is composed of filaments having a high elastic modulus or even if the fiber bundle transfer speed (running speed) is high when the fiber bundle is spread, and to provide a method for producing a spread fiber bundle using the production apparatus, and also to provide a method for producing a prepreg by impregnating a resin into spread fiber bundles produced by the production method.
DISCLOSURE OF THE INVENTION
The apparatus for producing a spread fiber bundle of the invention to solve the above problem comprises a group of at least two rollers kept in contact with a running fiber bundle, and a base body reciprocating to be repetitively brought into contact with and kept away from the running fiber bundle as the axial center of said base body moves relatively to the running fiber bundle, said base body being provided between at least a pair of rollers adjacent to each other in said group of rollers.
In the invention, the base body means a member used for spreading a transferred fiber bundle.
Particularly, the base body is a rod circular or polygonal in the cross sectional form (the cross section at right angles to the longitudinal direction). In the case of a polygonal rod, it is preferable that the angles are rounded to some extent.
The base body can be either a fixed body comprising a rod like member supported at both of its end portions without being rotated around the axis in the longitudinal direction thereof or a rotatable body comprising a rod like member supported at both of its end portions rotatably around the axis in the longitudinal direction thereof.
The rotatable body can be either an active rotating body positively driven to rotate or a passive rotating body not positively driven to rotate. In the case of the rotatable body, the base body is usually a rotating roller. The rotating roller used as an active rotating body may be called a driven rotating roller, and the rotating roller used as a passive rotating body may be called a free rotating roller. The rotating body can be either a concentric rotating body in which its rotating axial center is concentric with the peripheral form in the cross sectional form of the base body or an eccentric rotating body in which its rotating axis is eccentric.
The material of the base body can be any material that assures a sufficient strength against repeated contact with and separation from the running fiber bundle, and carbon steel, stainless steel or ceramics can be preferably used.
It is preferable that the surface roughness expressed as the arithmetic mean roughness Ra measured according to JIS B 0601, of the portion of the base body to be kept in contact with the fiber bundles is 0.4 to 3.2. A more preferable range is 0.8 to 1.6.
In the invention, the reciprocation to cause repeated contact and separation means that the base body is reciprocated in such a manner that the state in which the base body is kept in perfect contact with the running fiber bundles (the body contact state) and the state in which the base body is perfectly kept away from the running fiber bundles (the body non-contact state) are periodically repeated.
In the body non-contact state, the running fiber bundle does not receive any pressure from the base body, and are slackened and substantially free from tension partially in the running direction. In this slackened state, the minimum tension acting on spread regions of the fiber bundle is substantially zero.
In the apparatus for producing a spread fiber bundle of the invention, it is preferable that the base body is provided together with one or more identical bodies.
A reciprocating direction of the base body is substantially perpendicular to a running direction (a transferring direction) of the running fiber bundle and substantially perpendicular to the widthwise direction of the running fiber bundle. In the case where the running fiber bundle runs in the horizontal direction, the reciprocating direction coincides with the vertical direction.
In the apparatus for producing a spread fiber bundle of the invention, it is preferable that the base body is a rotatable roller.
In the apparatus for producing a spread fiber bundle of the invention, it is preferable that at least one roller of the group of rollers, or at least one body of the base bodies comprises a roller having a plurality of fiber bundle support portions extending along a direction of the rotating axis of the roller and projected from the surface of the roller, at the periphery of the roller.
In the case where a roller having projected support portions is used, when the running fiber bundle contacts the projected support portions, the running fiber bundle is momentarily held and spread, and the state in which the spread portions are kept into
Akase Daisaku
Matsumae Hidetaka
Ohtani Hiroshi
Tanaka Kiyotsugu
Tsuji Seiji
Piper Rudnick LLP
Tentoni Leo B.
Toray Industries Inc.
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