JPH06228837A - Thermoplastic yarn for composite - Google Patents

Abstract

PURPOSE:To obtain lightweight, tough and thermoplastic yarn for composites excellent in surface smoothness and further weaving and braiding properties. CONSTITUTION:This thermoplastic yarn (4) for composites is composed of discontinuous thermoplastic matrix fiber (1) of substantially no twist, discontinuous reinforcing fiber (2) of substantially no twist and thermoplastic matrix fiber (3) for the composites having a lower melting point than that of the fiber (1) and characterized by winding and covering combined filament yarn prepared from the fibers (1) and (2) at >=20% combined filament degree with the fiber (3) in an amount of >=1 to <=10wt.% based on the yarn (4) and further characterized by a lower melt viscosity of the thermoplastic yarn (4) for the composites and the fiber (3) than that of the fiber (1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber for a fiber reinforced composite in which a thermoplastic resin is made into a fiber and mixed with a reinforcing fiber.

[0002]

2. Description of the Related Art A yarn for a thermoplastic composite obtained by mixing continuous reinforcing fibers and a thermoplastic matrix fiber is disclosed in JP-A-60-209034 and JP-A-61-130.
It is disclosed in Japanese Patent No. 345 and the like.

However, when these conventional composite yarns are used as a blade, the continuous reinforcing fibers are damaged due to the difference in elongation between the continuous reinforcing fibers and the thermoplastic matrix fibers and the lack of their sizing property. Not only the operability is significantly deteriorated, but when the blade is molded, impregnation unevenness occurs, the obtained molded body lacks toughness, and a molded body with an excellent surface condition cannot be obtained. There was a problem. If a large amount of a surface treatment agent such as spinning oil is added to the above fiber in an attempt to improve the operability, the operability is improved to some extent, but the surface treatment agent causes an interface between the reinforcing fiber of the molded product and the matrix. There was a problem such as lower strength.

On the other hand, there is also a composite yarn in which a discontinuous reinforcing fiber and a thermoplastic matrix fiber are used to impart a twisting property to these fibers in a so-called spinning process so as to have a focusing property. When a blade is produced using this, it is possible to secure a considerable degree of operability. However, the physical properties of the obtained molded product cannot be obtained due to the twist. Further, even in the surface state, there is a problem that the so-called resin-rich portion exists because the distribution of the reinforcing fiber is non-uniform due to the twist.

As described above, the yarn for thermoplastic composite in which the reinforcing fiber and the thermoplastic matrix fiber are mixed is effective for solving the difficulty of impregnation due to the high viscosity of the thermoplastic resin. However, the yarn for thermoplastic composites which satisfies both the textile processability such as weaving property and braiding property and the physical properties of the composite obtained by molding has not yet been obtained.

[0006]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of various investigations by the present inventors on various measures for improving the surface condition of composites obtained by molding these thermoplastic composite yarns, a discontinuous thermoplastic matrix was obtained. A thermoplastic matrix fiber having a melting point lower than the melting point of the discontinuous thermoplastic matrix fiber, which is used for winding and coating the mixed fiber in which the fiber and the discontinuous reinforcing fiber are mixed, is used, and the weight of the thermoplastic matrix fiber is used. Is 1% by weight or more and 10% by weight or less with respect to the total weight of the thermoplastic composite yarn composed of these fibers, the mobility of the discontinuous reinforcing fibers during molding is improved, and the surface condition is improved. We have found that it is good. It was also found that if the melt viscosity of the thermoplastic matrix fiber is lower than the melt viscosity of the discontinuous thermoplastic matrix fiber, the surface condition of the composite will be better.

The present inventors have completed the present invention as a result of further studies based on such findings.

[0008]

That is, the present invention provides a substantially non-twisted discontinuous thermoplastic matrix fiber (1),
A yarn (4) for a thermoplastic composite, which comprises substantially non-twisted discontinuous reinforcing fibers (2) and a thermoplastic matrix fiber (3) having a lower melting point than that of (1),
And (2) in a mixed fiber with a mixing degree of 20% or more,
The melt viscosity of the thermoplastic composite yarn (4), which is obtained by winding-coating (3) of 1% by weight or more and 10% by weight or less with respect to (4), and (3). The above-mentioned yarn (4) for thermoplastic composites is provided which is characterized by having a melt viscosity lower than that of

The degree of mixed fiber is defined by the following equation.

[Equation 1] N: The total number of filaments of one kind among the filaments of each kind constituting the mixed fiber NcX: When the filament of one kind is divided into several groups, the number of the groups X: Each of the above The number of filaments in a specific one group in the group Also, in the above formula, 100 (N−X) / (N−1)
Means a mixed fiber state, and a smaller X means a higher mixed fiber state. NcX / (N / X) means how important the filament is in terms of visual effects in the entire mixed yarn.

Hereinafter, the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto. FIG. 1 schematically shows a typical example of the thermoplastic composite yarn in the present invention. A is an enlarged schematic view of a cross-sectional view of a thermoplastic composite yarn, and B is a schematic perspective view of a thermoplastic composite yarn. The thermoplastic composite yarn (4) of the present invention is a mixed filament yarn of a substantially untwisted discontinuous thermoplastic matrix fiber (1) and a substantially untwisted discontinuous reinforcing fiber (2), The thermoplastic matrix fiber (3) is wound and coated.

As the thermoplastic matrix fibers (1 or 3) constituting the thermoplastic composite yarn (4) of the present invention, polyamide fibers such as nylon 6 and nylon 66, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, Examples thereof include polyolefin fibers such as polyethylene and polypropylene, polyether ether ketone fibers, polyphenylene sulfide fibers, polyether imide fibers, and polycarbonate fibers. However, the thermoplastic matrix fiber (1 or 3) used in the present invention is not limited to the above fibers.

The reinforcing fiber (2) constituting the thermoplastic composite yarn (4) of the present invention is carbon fiber,
Examples include aramid fiber and glass fiber. However, the reinforcing fiber (2) used in the present invention is not limited to the above fibers.

Both the thermoplastic matrix fiber (1) and the reinforcing fiber (2) constituting the thermoplastic composite yarn (4) of the present invention must be substantially non-twisted discontinuous fibers. This is to prevent defects in the physical properties and surface state of the composite due to the displacement of the reinforcing fibers during molding when the composite is prepared by molding after making it into a textile product such as a blade or a woven fabric. That is, the use of non-twisted discontinuous fibers makes it possible to easily form a product having a complicated shape.

The average fiber length of the thermoplastic matrix fiber (1) and the reinforcing fiber (2) constituting the thermoplastic composite yarn (4) of the present invention is not particularly limited, but both are preferably 50 mm or more.

The thermoplastic matrix fiber (1) and the reinforcing fiber (2) constituting the thermoplastic composite yarn (4) of the present invention are mixed, and the mixing degree is 20%.
It is necessary to be above. When the content is 20% or more, the reinforcing fiber (2) is impregnated in a short time during melting, but when the degree of fineness is less than 20%, the impregnation is time-consuming and uneconomical. This is because the mechanical properties of the molded product deteriorate because they become insufficient. As a means for mixing fibers, each continuous fiber is separately drafted to obtain a sliver, and then the sliver is mixed and drafted,
A method of obtaining a mixed sliver, or a method of obtaining a sliver by drafting a continuous reinforcing fiber, and then mixing it with a matrix discontinuous sliver obtained by a card process or the like in a drawing process or a roving process to obtain a mixed sliver or mixed roving Any means such as a method of obtaining

The thermoplastic matrix fibers (3) constituting the thermoplastic composite yarn (4) of the present invention may be continuous fibers or discontinuous fibers. In the case of continuous fibers, it is also possible to open the fibers with an electric fiber opening device or use a processed yarn obtained by crimping. On the other hand, in the case of non-continuous fibers, it is sufficient that the fibers have a binding force that can satisfy the textile processability, and spun yarn having a small number of twists made of staples having a long fiber length is suitable.

The weight ratio of the thermoplastic matrix fiber (3) to the thermoplastic composite yarn (4) of the present invention must be 1% by weight or more and 10% by weight or less, and the thermoplastic matrix fiber ( In 3), it is necessary to coat the mixed yarn with winding. This is because, for the first time, it is possible to make the textile processability compatible with the physical properties of the obtained composite.

The weight ratio referred to here is defined by the following equation. Weight ratio = {C / (A + B + C)} × 100 (%) A; Amount of discontinuous thermoplastic matrix fiber (1) (g /
m) B: amount of reinforcing fiber (2) (g / m) C: amount of thermoplastic matrix fiber (3) (g / m)

In the actual process, the thermoplastic composite yarn (4) is heated and pressured to melt the discontinuous thermoplastic matrix fiber (1) and the thermoplastic matrix fiber (3). Then, it is impregnated with the reinforcing fiber (2) and becomes a composite through a cooling process. Therefore, as a factor controlling the physical properties and appearance of the composite, the above-mentioned two types of thermoplastic matrix fibers (1
And the molten state of 3). In the above, the main role of the thermoplastic matrix fiber (3) is textile processability. That is, a blade or a woven fabric can be obtained without damaging the reinforcing fiber (2) and without scattering or disturbing the orientation state, and further cut into a predetermined shape as a material for use in molding, and pre-shaped ( For example, it means to set in a mold) is to be satisfied. Once pre-shaped, it is important to melt as smoothly as possible and leave no trace of wound coating in the subsequent so-called molding process. If there are traces of the wound coating remaining, they are the main causes of two defects. One is the presence of a resin rich part. Needless to say, the presence of this not only impairs the surface appearance of the obtained molded product, but also deteriorates the mechanical properties of the molded product. The other one is that the restraining force by the thermoplastic matrix fiber (3) worked during molding, and the reinforcing fiber (2)
This is a lack of physical properties between fiber bundles due to insufficient spacing. In order not to generate these defects, the weight ratio of the thermoplastic matrix fiber (3) needs to be 10% by weight or less, while in order to satisfy the above-mentioned textile processability, the weight ratio is 1% by weight or more. It is necessary to have it.

The melting point of the thermoplastic matrix fiber (3) constituting the thermoplastic composite yarn (4) of the present invention must be lower than the melting point of the discontinuous thermoplastic matrix fiber (1). This is because if the melting point of (3) is lower than the melting point of (1) in the above weight ratio range, the wound coated fiber (3) will melt faster during molding and hinder the movement of the main fiber bundle. This is because the impregnation is further improved and the physical properties and surface properties of the molded product are improved.

The thermoplastic matrix fiber (3) constituting the yarn (4) for thermoplastic composite of the present invention.
It is more preferable that the melt viscosity of is lower than the melt viscosity of the discontinuous thermoplastic matrix fiber (1). This is (3)
If the melt viscosity of (1) is lower than the melt viscosity of (1), the fluidity at the time of molding is excellent, and the surface condition of the obtained composite is further improved. That is, when both the melting point and the melt viscosity of (3) are lower than the melting point and the melt viscosity of (1), the binding force to the reinforcing fiber (2) at the time of molding is reduced, and at the same time, the resin flow becomes easy. This is because the physical properties and surface characteristics of the composite used are further improved.

A so-called spinning oil is generally used as the surface treatment agent for the thermoplastic matrix fiber in order to maintain the passability in the fiber manufacturing process and the subsequent process. However, it is preferable not to use this type of treating agent as much as possible because it inhibits the adhesive force between the reinforcing fiber of the composite and the matrix interface.

The weight ratio of the reinforcing fiber (2) to the thermoplastic composite yarn (4) of the present invention is not particularly limited, but is preferably in the range of 30 to 80% by weight.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

EXAMPLE 1 Melting point 215 ° C. as discontinuous thermoplastic matrix fiber,
Nylon 6 fiber having a relative viscosity of 2.2 when melted, carbon fiber as a discontinuous reinforcing fiber, melting point of 180 ° C. as a thermoplastic matrix fiber, nylon 12 fiber having a relative viscosity of 2.2 at the time of melting and 40 denier / 12 filaments Using. The former two fibers were both untwisted and had an average fiber length of 100 mm. Nylon 6 fiber and carbon fiber were respectively drafted to obtain a sliver, and then the sliver was mixed with a kneading machine and drafted to obtain a mixed sliver. The weight of the mixed sliver was 536 gelen / 6 yards. A predetermined draft was applied to the mixed sliver, the mixture was supplied to a covering machine, and nylon 12 fibers were wound and coated in the S direction and the Z direction to obtain a yarn for thermoplastic composite of Nm1.7. The weight ratio of the carbon fibers to the thermoplastic composite yarn is 59% by weight, the weight ratio of the nylon 12 fibers is 1.5% by weight, and the blending degree of the untwisted mixed yarn is 65%.
Met. Using the thermoplastic composite yarn 32
A three-layer blade having an angle of 30 ° and an inner diameter of 20 mm was prepared using a round-striking machine. A silicon tube was put on the outer circumference of the mandrel during braiding, and after braiding, it was removed from the mandrel together with the blade. The braiding property of the thermoplastic composite yarn was good. The blade is set to a pressure of 15 Kg / cm ² and a temperature of 25
Internal pressure molding under conditions of 5 ° C and holding time of 20 minutes, thickness 0.8
A mm hollow pipe was obtained. The hollow pipe had excellent surface properties and was a good pipe without a resin rich portion. The results are shown in Table 1.

Example 2 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, as the thermoplastic matrix fiber, the melting point is 180 ° C., the relative viscosity upon melting is 2.2, 140 denier /
48 filaments of nylon 12 fiber were used. Therefore, the weight ratio of nylon 12 fiber for winding coating is 7.2% by weight.
Met. Using the obtained thermoplastic composite yarn, a hollow pipe was produced in the same manner as in Example 1. The hollow pipe had excellent surface properties and was a good pipe without a resin rich portion. The results are also shown in Table 1.

Example 3 Using the thermoplastic composite yarn prepared in Example 1, a woven fabric having a basis weight of 15 warps / inch was prepared. This fabric is placed in a mold at a temperature of 250 ° C and a pressure of 10 kg.
/ Cm ² and a holding time of 15 minutes, pressurization was performed, then cooling was performed and the plate was taken out from the mold to form a flat plate. The flat plate was a good pipe having excellent surface properties and no resin rich portion. The weavability of the used thermoplastic composite yarn was good. The results are also shown in Table 1.

Example 4 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, the thermoplastic matrix fiber has a melting point of 180 ° C., a relative viscosity of 2.0 when melted, and 40 denier / 1.
Two filaments of nylon 12 fiber were used. Therefore,
The weight ratio of nylon 12 fiber for winding coating is 1.5% by weight.
Met. Using the obtained thermoplastic composite yarn, a hollow pipe was produced in the same manner as in Example 1. The hollow pipe had a very excellent surface property and had no resin rich portion, and was a very good pipe. Further, the braiding property of the used thermoplastic composite yarn was good. The results are also shown in Table 1.

Comparative Example 1 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, the degree of mixing of the mixed fiber was 12%. In the obtained thermoplastic composite yarn, damage and cutting of carbon fiber were observed during braiding, but it was possible to use it as a blade for the time being. A hollow pipe was produced in the same manner as in Example 1 using the blade. The obtained pipe had a portion with insufficient impregnation and had poor surface properties. The results are also shown in Table 1.

Comparative Example 2 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, as the thermoplastic matrix fiber, the melting point is 180 ° C., the relative viscosity upon melting is 2.2, 40 denier / 1
A single 2-filament nylon 6 fiber was wound and coated only in the S direction. Therefore, the weight ratio of the nylon 6 fiber for winding coating was 0.7% by weight. This mixed fiber has poor braiding properties, the carbon fibers are damaged or cut during the braiding, and the working environment is significantly deteriorated, and the obtained blade has a lot of fluff on the surface condition and the fiber arrangement is disturbed. It was a thing. Therefore, making a hollow pipe was abandoned.

Comparative Example 3 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, the thermoplastic matrix fiber has a melting point of 180 ° C., a relative viscosity of 2.2 when melted, and 300 denier /
Two 60-filament nylon 6 fibers were used, one was wound in the S direction and the other was wound in the Z direction to form a mixed yarn. The number of windings was 180 T / M. Therefore, the weight ratio of the nylon 6 fiber for winding coating was 16% by weight. The braidability of the obtained thermoplastic composite yarn was good, but the yarn was generally hard and lacked in flexibility. Molding was carried out using this blade, but because the binding force of the nylon 6 fiber for winding coating was too strong, a large number of resin rich parts were formed on the surface of the hollow pipe, and it was not practical.

Comparative Example 4 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, as the thermoplastic matrix fiber for winding coating, the same melting point as that of the discontinuous thermoplastic matrix fiber, 215 ° C., and the relative viscosity upon melting, 2.2, 40 denier / 1
Two filaments of nylon 6 fiber were used. Using the obtained thermoplastic composite yarn, a hollow pipe was produced in the same manner as in Example 1. On the surface of the hollow pipe, minute pinholes and resin-rich portions recognized as wound coated fibers were scattered. The braidability of the used thermoplastic composite yarn was good. The results are also shown in Table 1.

[0033]

[Table 1]

[0034]

INDUSTRIAL APPLICABILITY The present invention provides a thermoplastic composite yarn useful for molding a thermoplastic composite which is lightweight, tough and has excellent surface smoothness. That is, the thermoplastic composite yarn of the present invention is a blade, a woven fabric, a knitted fabric, etc., for example, a round punching blade is manufactured by a round punching machine, a so-called bag material such as a silicon tube is inserted therein, and an internal pressure molding method, etc. To form a frame or bat for a tennis racket or a bamington racket, or to form a molded product for the same purpose as described above by weaving it into a predetermined shape using a circular loom or the like, and an ordinary biaxial loom It is possible to lay-up the woven fabric obtained by using the above, or to obtain a flat plate formed by using a press molding machine and then perform deep drawing to use it for a helmet or the like. As described above, the yarn for thermoplastic composite of the present invention can be applied to a wide range of molding methods, and its effect is extremely large.

[Brief description of drawings]

FIG. 1 is an example of a schematic view of a thermoplastic composite yarn of the present invention.

[Explanation of symbols]

 A: Section of yarn for thermoplastic composite of the present invention B: Part of yarn for thermoplastic composite of the present invention 1: Discontinuous thermoplastic matrix fiber for mixed fiber 2: Fiber for discontinuous reinforcement for mixed fiber 3: thermoplastic matrix fiber for winding coating 4: thermoplastic composite yarn of the present invention

Claims (2)

[Claims] 1. A thermoplastic comprising substantially untwisted discontinuous thermoplastic matrix fibers, substantially untwisted discontinuous reinforcing fibers, and thermoplastic matrix fibers having a lower melting point than said discontinuous thermoplastic matrix fibers. A yarn for a composite, wherein the discontinuous thermoplastic matrix fiber and the discontinuous reinforcing fiber are mixed and mixed at a mixing degree of 20% or more, and 1 for the thermoplastic composite yarn.
A yarn for a thermoplastic composite, which is obtained by winding-wrapping the thermoplastic matrix fiber in an amount of 10% by weight or more and 10% by weight or less. 2. The yarn for a thermoplastic composite according to claim 1, wherein the melt viscosity of the thermoplastic matrix fiber is lower than the melt viscosity of the discontinuous thermoplastic matrix fiber.