JPH0226938A - Yarn material for fiber-reinforced plastic - Google Patents

Abstract

PURPOSE:To obtain the title twist-free yarn material having excellent stability of structure, flexibility and economic efficiency by bonding fibers prepared by forming a thermoplastic resin for matrix into a film and splitting the film to reinforcing fibers with part of the thermoplastic fibers to fix structure. CONSTITUTION:Twist-free reinforcing fiber yarn 1 and a film 2 obtained from a thermoplastic resin for matrix are sent through guides 3 and 3', respectively, piled by a guide roll 4, the film 2 is split by a splitting roll 5 to give split fibers and the reinforcing fiber yarns is combined with stable fiber to prepare mixed yarn 7. Then the yarn is falsely twisted by a falsely twisting spindle 8, the thermoplastic fiber resin is partially melted by a heat plate 12 and bonding structure is fixed to give the aimed yarn material.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to thermoplastic fiber reinforced plastics (hereinafter referred to as FRTP).
) relates to a novel yarn material used in the production of

<Problems to be solved by conventional technology and invention> FRTP
As one of the raw materials used in the production of, yarns containing a mixture of reinforcing fibers and thermoplastic resins are sometimes used.

(Specifically, body) Thermoplastic resin powder is dispersed in reinforcing fiber yarn (B) Reinforcing fiber is covered with thermoplastic resin film (C) Thermoplastic resin is made into continuous filaments and reinforced fiber yarn Threads and intertwisted or mixed fibers C% Established in the 1980s
-209033, No. 60-209034) (so-called commingle yarn or intermingle yarn).

All of these threads were made with flexibility and uniform mixing properties in mind for handling requirements, but these conventional threads have the following problems.

The yarn material EP-'''C classified as the above-mentioned type has the disadvantage that the thermoplastic resin powder cannot be accurately dispersed and distributed in the reinforcing fiber yarn, or that it falls off during the process.

In yarns classified as (B), the thermoplastic resin film is unevenly distributed around the outer periphery of the reinforcing fiber yarn, creating a space closed by the film inside the yarn, which causes problems in impregnating the thermoplastic resin and creating voids. Easy to leave behind.

In the case of yarns classified as (C), the thermoplastic resin must be subjected to a spinning process in advance, which is disadvantageous in terms of cost.

Secondly, in the case of twisted yarns, the thermoplastic resin is unevenly distributed around the outer periphery of the reinforcing fiber threads, and the reinforcing fiber threads are bunched together due to heating.
This results in uniform fiber distribution and deterioration of the physical properties of FRTP.

Thirdly, in the case of mixed fiber yarns, the thermoplastic fibers that have been mixed together will refocus during handling of the mixed fiber yarns (because their elongation characteristics are different), so it is necessary to perform some kind of tissue fixation. Sizing treatment using a chemical agent is performed. In addition, due to the stress relaxation of the spun thermoplastic fiber yarn, and furthermore due to the shrinkage stress during heating and melting of the thermoplastic fiber for impregnation, the reinforcing fiber yarn takes on a loop shape, which reduces the linearity of the reinforcing fiber yarn. This may cause a decrease in physical properties.

The present invention relates to a new yarn structure that solves the drawbacks of the conventional fiber yarn as described above, in which thermoplastic fibers and reinforcing fibers are mixed as IJ Fuchs resin.

Means for Solving the Problems〉 That is, the gist of the present invention is to provide reinforcing fibers and materials.
In a yarn product containing a thermosetting fibrous material for IJ box, the thermoplastic fibrous material or the split fiber or spun yarn obtained by splitting the thermoplastic resin for IJ box after forming into a film. The present invention is a virtually untwisted yarn for fiber-reinforced plastics, which is a staple fiber obtained at L° C. and whose adhesive structure is fixed by a portion of the thermoplastic fibrous material.

Typical materials for reinforcing fiber yarns include inorganic yarns such as glass fibers and carbon fibers, and organic fiber yarns such as aramid fibers. All of these are preferably tow-like materials without twist.

The yarn structure most often used to mix thermoplastic fibers into these yarns is the method classified into the prior art (C) described above. In this method, non-twisted or extremely low-twist thermoplastic continuous filament yarn (hereinafter referred to as filament yarn) is used as the thermoplastic fiber yarn. Uniform mixing is extremely difficult. This is because the two materials to be mixed are both continuous bodies and have different elongation properties.

In the filament of the present invention, the thermoplastic fibrous material for the matrix is a split fiber obtained by splitting a film-like material of a thermoplastic resin for the matrix, or a staple fiber obtained by spinning the resin.

Film-like products can generally be produced at a low stretching ratio, and shrinkage stress can be kept low during melting. Further, since the split fibers do not transmit stress continuously like a normal filament, the generated stress is released at the cut portion of the split fibers, and the same applies to the pull fibers. That is, although staple fibers have a higher draw ratio in production than split fibers, since each fiber is cut, all stress generated is released at its ends. Therefore, the reinforcing fiber yarn can maintain linearity without exhibiting a loop shape.

Furthermore, when mixing with reinforcing fiber yarn, it is difficult to mix uniformly with filament yarn because the stress propagates over a long range, whereas with split fiber or staple fiber, the fibers exist almost independently. , we can easily mix uniformly. In order for the yarn material of the present invention to fully exhibit the above-mentioned characteristics of split fibers or staple fibers, K is such that the obtained mixed yarn has no split fibers or staple fibers in the mixed yarn in an unheated state. It is characterized by its existence and fixedness.

Furthermore, the fixation is carried out locally so that the thread has sufficient flexibility.

When fixing split fibers or staple fibers by heating, it is inevitable that the physical properties of the finished product will deteriorate due to the propagation of shrinkage stress and heating of the reinforcing fiber threads.

The reinforcing fiber yarn constituting the yarn of the present invention may be substantially untwisted glass fiber, carbon fiber, inorganic fiber such as alumina fiber, or tow-like fiber having a high melting point or no melting point such as aramid fiber. It is a thing. Furthermore, the split fibers or staple fibers used are those obtained from thermoplastic resins such as polyamide, polyester, polypropylene, polyethylene, polyimide, polyether ketone, etc., depending on the melting point of the reinforcing fibers and the use. It does not limit the type.

The yarn material of the present invention is obtained by, for example, a yarn material in which reinforcing fibers and a thermoplastic fibrous material for matrix are mixed, and a portion of the thermoplastic fibrous material is melted or treated with a solvent in a state in which false twisting is applied. Manufactured by dissolving. The thermoplastic fibrous material is a split fiber obtained by splitting a film material made of a thermoplastic resin, or a staple fiber obtained by spinning.

A detailed explanation will be given below according to the drawings.

In Figure 1, substantially untwisted reinforcing fiber yarns (1) and M)
Film obtained from thermoplastic resin for IJ box (2
) are each passed through the guides (3) and (3') and are combined together by the guide roll (4). At this time, it is preferable that the reinforcing fiber threads be sufficiently tensioned and that each single fiber be oriented along the direction of its movement. Immediately after this reinforcing fiber yarn and film laminate leaves the guide roll (4), the film is split by a split roll (5) having a number of blades on its surface. However, since the reinforcing fiber threads are sufficiently tensioned and oriented, and the moving direction of the cutter of the split roll (5) coincides with the orientation direction of the reinforcing fiber threads, the degree of damage to the reinforcing fibers is extremely small. In addition, since the film and the reinforcing fibers are processed in the form of a thin sheet in this slit section, the split fibers obtained from the film and the reinforcing fibers are mixed and taken off via a guide roll (6).

The state of the split fibers in the mixed thread (7) of reinforcing fibers and split fibers that has passed through the guide roll (6) is still unstable, and the tissue is fixed by applying a glue in the conventional binding process. However, in the method of the invention the false twist is imparted by a false twist spindle (8).

False twisting is performed with the false twisting spindle (8) at the center, and the guide roll (6) side and the nip roll (10) @ are heated in opposite directions, but the structure of the false twisting spindle is not particularly limited. (9) is a guide.

Heating further promotes mixing of reinforcing fibers and split fibers. Furthermore, by selecting the width of the reinforcing fiber yarn and film supplied to the guide roll (4), it is also possible to control the mixing state of both temperatures.

The false-twisted mixed yarn (11) is brought into contact with a heat plate heated above the melting point of the split fibers, and a part of the split fibers existing on the outer periphery of the yarn is melted, causing the mixed yarn to A fixed point is created on the outer circumference of the strip. Such fixing points can also be formed by spraying a spot of heated gas heated above the melting point onto the yarn instead of using a heat plate.

The fixing point obtained in this way fixes the outer periphery of the yarn in a spiral manner in the longitudinal direction of the yarn when the mixed yarn passes through the nip roll and is untwisted. The degree of fixation can be arbitrarily selected by changing the number of false twists, yarn speed, and length of the heater plate.

Furthermore, if a solvent is available that is effective for the split fibers, the fixing process can be performed by using a solvent coater roll instead of the heater plate.

Furthermore, as far as fixing the yarn structure is concerned, regardless of the method of constructing the yarn, the method of fixing the yarn structure of the present invention is the method of performing an adhesive treatment by melting and dissolving the yarn in a state where the yarn is false twisted. This is an effective method for fixing a thread structure while maintaining flexibility in the thread.

The mixed yarn that has passed through the nip rolls (10) has some crimp in the split fibers caused by the false twisting and bonding process, so it is strengthened by heating and applying tension near the secondary dislocation point of the split fibers. It is possible to obtain a good mixed yarn in which the fibers have no loops and are substantially untwisted, and split fibers are mixed and fixed.

The yarn fixing method of the present invention is a more effective method for the yarn structure whose manufacturing method is shown in FIG.

That is, staple fibers (13) obtained by spinning i-trix resin onto a pair of delivery rolls (14) are made into slivers using a normal sliver manufacturing method, are supplied together with reinforcing fiber threads (1), and are immediately transferred to a false twisting spindle. (7)
When false twisting is applied, there is an advantage that a better mixed state and fixed state can be obtained compared to the above-mentioned split fiber mixing.

The use of staple fibers as the matrix resin component has the same effect as solving the disadvantages of conventional filament commingling yarns or intermingling yarns by using split fibers.

<Example> The present invention will be explained in more detail with reference to Examples below.

Example 1 Tension was applied to 12 tows of untwisted well-washed carbon fibers and the tows were passed through a guide bar to form a ribbon-like carbon fiber yarn with a width of 18 m1B and a thickness of 20 mm with a melting point of 110 to 120 °C. A copolyamide film having a width of 201 microns and a width of 201 microns was supplied to the stacking and splitting section. The split part is a rotary split cutter with a split knife so that a split width of 0.5fi can be obtained.

The mixed yarn of carbon fiber and polyamide split fiber that had passed through the split section was false twisted at a rate of 150 times/m and was brought into continuous contact with a hot plate having a width of 5 mm heated to 150°C.

This contact with the hot plate melted the fuzz of the split fibers that had occurred in the yarn, fixed the structure, and resulted in a smooth yarn. Furthermore, when passing through the nip roll (10), approximately 10
By blowing heated air at 0° C. and applying tension, it was possible to obtain a mixed yarn in which split fibers were mixed and the carbon fibers had excellent linearity.

Example 2 Twelve tows of untwisted, well-washed carbon fibers were tensioned and passed through a guide and parr to form a ribbon-like carbon fiber yarn with a width of 25 m.

On the other hand, PBT (polybutylene terephthalate) resin having a melting point of 220°C was spun into staple fibers with a single fiber of 3 deniers and an average fiber length of 76 fibers, and a roving-like sliver of 0.8 fim was obtained through a normal spinning process. was supplied through a delivery roll (14) shown in FIG. 2 and a condenser guide with a width of 20 m. The mixed yarn of carbon fiber yarn (1) and sliver yarn (13) that comes out of the delivery roll (14) is immediately transferred to the false twist spindle (7).
) was applied with a twist of 120 T/m, and structural fixation was carried out by heat play (12) heated to 250°C. [Although the obtained mixed yarn had fluff of PBT fibers on its surface, the linearity of the carbon fiber yarn was well maintained, and the mixed state was good and stable.

<Effects of the Invention> The substantially untwisted fiber-reinforced plastic yarn of the present invention is a novel material that has excellent structural stability and flexibility, and is more economical than conventional techniques. .

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams showing the method for producing a filament for fiber-reinforced plastic of the present invention. 1...Fiber yarn 2...Film 3.3'...Guide 4.6...Guide roll 5...Sufu' IJt roll 7... ... Mixed yarn 8 ... False twist spindle 9 ... Guide 10 ... Nip roll 11 ... Mixed yarn 12 ... Heat plate 13 ...・Staple fiber 14...Terry roll number 1

Claims (1)

[Claims] In a yarn product in which a reinforcing fiber and a thermoplastic fibrous material for a matrix are mixed, the thermoplastic fibrous material is a split fiber obtained by splitting a thermoplastic resin for a matrix after forming it into a film, or a fiber obtained by spinning. A substantially untwisted yarn for fiber-reinforced plastics which is a staple fiber and whose adhesive structure is fixed by a part of the thermoplastic fibrous material.