JP3178562B2 - Yarn for thermoplastic composites - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced composite yarn obtained by converting a thermoplastic resin into fibers and blending the fibers with reinforcing fibers.

[0002]

2. Description of the Related Art Thermoplastic composite yarns in which continuous reinforcing fibers and thermoplastic matrix fibers are blended are disclosed in JP-A-60-209034 and JP-A-61-130.
No. 345, for example.

However, when these conventional composite yarns are braided, the continuous reinforcing fibers are damaged due to the difference in elongation between the continuous reinforcing fibers and the thermoplastic matrix fibers and their lack of convergence. Not only is the workability significantly inferior, but when the blade is formed, impregnation spots occur, or the obtained molded body lacks toughness, and it is not possible to obtain a molded body with excellent surface condition There was a problem. In order to improve the operability, if a large amount of a surface treatment agent such as a spinning oil is applied to the above-mentioned fibers, the operability is improved to some extent, but due to the surface treatment agent, the interface between the reinforcing fibers of the molded article and the matrix is increased. There were problems such as low strength.

On the other hand, there is also a composite yarn in which discontinuous reinforcing fibers and thermoplastic matrix fibers are twisted in a so-called spinning process to impart bunching properties. If this is used to create a blade, it is possible to ensure a considerable degree of operability. However, the physical properties of the obtained molded body cannot be satisfactory due to twisting. Further, even in the surface state, there is a problem that a so-called resin-rich portion exists because the distribution of the reinforcing fibers becomes uneven due to the twisting.

[0005] As described above, the thermoplastic composite yarn in which the reinforcing fiber and the thermoplastic matrix fiber are mixed is an effective yarn for solving the difficulty of impregnation due to the high viscosity of the thermoplastic resin. However, at present, there is no thermoplastic composite yarn that satisfies both the textile processability such as weaving and braiding properties and the physical properties of the composite obtained by molding.

[0006]

SUMMARY OF THE INVENTION The present inventors have studied various measures for improving the surface condition of a composite obtained by molding these thermoplastic composite yarns, and as a result, have found that a discontinuous thermoplastic matrix is obtained. The melting point of the thermoplastic matrix fiber for winding and covering the mixed yarn obtained by mixing the fiber and the discontinuous reinforcing fiber is lower than the melting point of the discontinuous thermoplastic matrix fiber, and the weight of the thermoplastic matrix fiber is used. Is not less than 1% by weight and not more than 10% by weight with respect to the total weight of the thermoplastic composite yarn composed of these fibers, whereby the mobility of the discontinuous reinforcing fibers at the time of molding is improved and the surface condition is improved. I found it to be good. Further, it has been found that when the melt viscosity of the thermoplastic matrix fiber is lower than the melt viscosity of the discontinuous thermoplastic matrix fiber, the surface state of the composite becomes better.

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

[0008]

That is, the present invention provides a substantially non-twisted discontinuous thermoplastic matrix fiber (1),
A thermoplastic composite yarn (4) comprising a substantially non-twisted discontinuous reinforcing fiber (2) and a thermoplastic matrix fiber (3) having a lower melting point than (1), wherein (1)
And (2) are mixed at a mixed degree of 20% or more.
The melt viscosity of the thermoplastic composite yarn (4), wherein (3) is wound and coated in an amount of 1% by weight or more and 10% by weight or less with respect to (4), and the melt viscosity of (3) is (1). The thermoplastic composite yarn (4) is characterized in that it has a lower melt viscosity than the above.

Here, the degree of blending is defined by the following equation.

(Equation 1) N: the total number of one type of filament among the various types of filaments constituting the mixed yarn NcX: the number of groups when the one type of filament is divided into several groups X: each of the above groups In the group, the number of filaments in one specific group Also, in the above formula, 100 (NX) / (N-1)
Means a mixed state, and the smaller the X, the higher the mixed state. NcX / (N / X) means how important the filament has to the visual effect in the whole mixed yarn.

Hereinafter, the present invention will be described in detail 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 cross-sectional view of the thermoplastic composite yarn, and B is a schematic perspective view of the thermoplastic composite yarn. The thermoplastic composite yarn (4) of the present invention comprises a mixed yarn of a substantially non-twisted discontinuous thermoplastic matrix fiber (1) and a substantially non-twisted non-continuous reinforcing fiber (2), The thermoplastic matrix fiber (3) is wound and covered.

The thermoplastic matrix fibers (1 or 3) constituting the thermoplastic composite yarn (4) of the present invention include polyamide fibers such as nylon 6 and nylon 66, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, and the like. Examples include polyolefin fibers such as polyethylene and polypropylene, polyetheretherketone fibers, polyphenylenesulfide fibers, polyetherimide fibers, and polycarbonate fibers. However, the thermoplastic matrix fibers (1 or 3) used in the present invention are not limited to the above fibers.

The reinforcing fibers (2) constituting the thermoplastic composite yarn (4) of the present invention include carbon fibers,
Aramid fiber, glass fiber and the like can be mentioned. However, the reinforcing fibers (2) used in the present invention are not limited to the above fibers.

Both the thermoplastic matrix fibers (1) and the reinforcing fibers (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 composite physical properties and surface condition from being caused by the displacement of the reinforcing fibers during molding when forming a composite after forming a textile product such as a blade or woven fabric. That is, by using the non-twisted discontinuous fiber, it is possible to form a product having a complicated shape without difficulty.

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 is 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 degree of mixing is 20%.
It is necessary to be above. If the content is 20% or more, impregnation into the reinforcing fiber (2) is performed in a short time at the time of melting, but if the degree of mixing is less than 20%, impregnation takes time and is uneconomical. This is because the mechanical properties of the molded article are reduced due to insufficient molding. In addition, as a means of blending, after each continuous fiber is separately cut to obtain a sliver, the slivers are mixed and cut,
A method of obtaining a mixed sliver, or a method of drawing a continuous reinforcing fiber, obtaining a sliver, mixing with a matrix non-continuous sliver obtained by a card process or the like in a drawing process or a roving process, and mixing a sliver or a mixed roving yarn Any method such as a method for 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 use an electric fiber opening device, or use a processed yarn obtained by crimping or the like. On the other hand, in the case of non-continuous fibers, it is sufficient that the fibers have a binding force that satisfies textile workability, and a spun yarn with a small number of twists made of staple 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 not less than 1% by weight and not more than 10% by weight. In 3), it is necessary to wind and coat the mixed yarn. This is because for the first time, it is possible to achieve both the textile processability and the physical properties of the obtained composite.

The weight ratio 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 an actual process, the discontinuous thermoplastic matrix fiber (1) and the thermoplastic matrix fiber (3) are melted by applying heat and pressure to the thermoplastic composite yarn (4). Then, it is impregnated into the reinforcing fibers (2) and becomes a composite through a cooling process. Therefore, the two types of thermoplastic matrix fibers (1) are the factors that govern the physical properties and appearance of the composite.
And 3) the molten state. The main role of the thermoplastic matrix fiber (3) is in the textile processability. That is, the blade or the woven fabric is obtained without damaging the reinforcing fiber (2) and without scattering or disturbing the orientation state, and is further cut into a predetermined shape as a material to be subjected to molding, and preformed ( For example, it means to set in a mold or the like). Once the pre-shaping has been performed, it is important in the subsequent so-called forming step to melt as smoothly as possible and leave no trace of the wound coating. If traces of the wound coating remain, it mainly causes two defects. One is the presence of a resin-rich portion. Needless to say, the presence thereof not only impairs the surface appearance of the obtained molded article, but also deteriorates the mechanical properties of the molded article. The other one is that the restraining force of the thermoplastic matrix fiber (3) worked during molding and the reinforcing fiber (2)
There is insufficient physical property between the fiber bundles due to insufficient dispersion between the fiber bundles. In order to avoid these drawbacks, it is necessary that the weight ratio of the thermoplastic matrix fiber (3) is not more than 10% by weight, while in order to satisfy the above-mentioned textile processability, the weight ratio is not less than 1% by weight. Something is needed.

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

The thermoplastic matrix fiber (3) constituting the thermoplastic composite yarn (4) of the present invention.
Is more preferably 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 during molding is excellent, and the surface state of the obtained composite is further improved. That is, if 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) during molding is reduced, and the resin flow is also facilitated, and This is because the physical properties and surface properties of the resulting composite are further improved.

As a surface treating agent for the thermoplastic matrix fiber, a so-called spinning oil is generally used in order to maintain the property of passing through the fiber manufacturing process and the post-process. However, this type of treating agent inhibits the adhesive force between the reinforcing fiber of the composite and the matrix interface, and is therefore preferably not used as much as possible.

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]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 A non-continuous thermoplastic matrix fiber having a melting point of 215 ° C.
Nylon 6 fiber having a relative viscosity of 2.2 at the time of melting, carbon fiber as a non-continuous reinforcing fiber, nylon 12 fiber having a melting point of 180 ° C., a relative viscosity at the time of melting 2.2 and 40 denier / 12 filaments as a thermoplastic matrix fiber. Using. The former two fibers were both untwisted and had an average fiber length of 100 mm. The nylon 6 fiber and the carbon fiber were each drawn to obtain slivers, and then the slivers were mixed with a drawing machine and drafted to obtain a mixed sliver. The weight of the mixed sliver was 536 selenium / 6 yards. A predetermined draft was applied to the mixed sliver and supplied to a covering machine. The mixed sliver was wound and coated with nylon 12 fibers in the S and Z directions to obtain a thermoplastic composite yarn having an Nm of 1.7. The weight ratio of carbon fibers to the thermoplastic composite yarn is 59% by weight, the weight ratio of nylon 12 fibers is 1.5% by weight, and the degree of mixing of the untwisted mixed yarn is 65%.
Met. Using the thermoplastic composite yarn, 32
A blade composed of three layers having an angle of 30 ° and an inner diameter of 20 mm was prepared using a round driving machine. At the time of braiding, a silicon tube was placed over the outer periphery of the mandrel, and after braiding, the blade was removed from the mandrel together with the blade. The braiding properties of the thermoplastic composite yarn were good. A pressure of 15 kg / cm ² and a temperature of 25 were applied to the blade.
Internal pressure molding under conditions of 5 ° C. and holding time of 20 minutes, thickness 0.8
mm hollow pipe was obtained. The hollow pipe was a good pipe with excellent surface properties and no resin-rich portion. Table 1 shows the results.

Example 2 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, the melting point is 180 ° C., the relative viscosity at the time of melting is 2.2, 140 denier /
A 48 filament nylon 12 fiber was used. Therefore, the weight ratio of the nylon 12 fiber for winding coating is 7.2% by weight.
Met. Using the thermoplastic composite yarn thus obtained, a hollow pipe was produced in the same manner as in Example 1. The hollow pipe was a good pipe with excellent surface properties and no resin-rich portion. The results are shown in Table 1.

Example 3 Using the thermoplastic composite yarn prepared in Example 1, a woven fabric having a basis weight of 15 yarns / 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, followed by cooling and taking out of the mold to form a flat plate. The flat plate was a good pipe with excellent surface properties and no resin-rich portion. The weaving property of the thermoplastic composite yarn used was good. The results are shown in Table 1.

Example 4 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, the melting point is 180 ° C. and the relative viscosity at the time of melting is 2.0, 40 denier / 1 as a thermoplastic matrix fiber.
Two filament nylon 12 fibers were used. Therefore,
The weight ratio of nylon 12 fiber for winding coating is 1.5% by weight.
Met. Using the thermoplastic composite yarn thus obtained, a hollow pipe was produced in the same manner as in Example 1. The hollow pipe had a very good surface property and was a very good pipe without any resin-rich portion. The braiding properties of the thermoplastic composite yarn used were good. The results are 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 blending of the blended yarn was 12%. In the obtained thermoplastic composite yarn, carbon fibers were damaged or cut during braiding, but could be used as a braid. Using the blade, a hollow pipe was formed in the same manner as in Example 1. The resulting pipe had imperfectly impregnated portions and poor surface properties. The results are shown in Table 1.

Comparative Example 2 A thermoplastic composite yarn was prepared in the same manner as in Example 1. However, as a thermoplastic matrix fiber, the melting point is 180 ° C., the relative viscosity at the time of melting is 2.2, 40 denier / 1.
One 2-filament nylon 6 fiber was used for winding coating 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, carbon fibers are damaged and cut during braiding, and the working environment is remarkably deteriorated, and the obtained blade has a very large surface condition and has a disordered fiber arrangement. Was something. 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 melting point is 180 ° C., the relative viscosity at the time of melting is 2.2, 300 denier /
Two nylon 6 fibers of 60 filaments were used, and one was a mixed fiber wound and coated in the S direction and the other was wound in the Z direction. The number of windings was also set to 180 T / M. Therefore, the weight ratio of the nylon 6 fiber for winding coating was 16% by weight. Although the obtained thermoplastic composite yarn had good braiding properties, the yarn was generally hard and lacked flexibility. Molding was performed using the blade. However, since the binding force of the nylon 6 fiber for wound coating was too strong, many resin-rich portions were formed on the surface of the hollow pipe, and the resin was not practical.

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

[0033]

[Table 1]

[0034]

According to the present invention, there is provided a thermoplastic composite yarn useful for forming a thermoplastic composite which is lightweight, tough, and excellent in surface smoothness. That is, the thermoplastic composite yarn of the present invention is a blade, a woven fabric and a knitted fabric, 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 forming method and the like Molding of frames or bats for tennis rackets, badminton rackets, etc., and molding of molded products for the same applications as described above by weaving into a predetermined shape using a circular loom, etc., and also a normal two-axis loom It can be used for a helmet or the like by laying up a woven fabric obtained by using a method such as a method described above, or obtaining a flat plate formed by using a press forming machine or the like and then performing deep drawing. As described above, the thermoplastic composite yarn of the present invention is applicable to a wide range of molding methods, and the effect is extremely large.

[Brief description of the drawings]

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

[Explanation of symbols]

 A: Cross-section of the thermoplastic composite yarn of the present invention B: Part of the thermoplastic composite yarn of the present invention 1: Discontinuous thermoplastic matrix fiber for mixed yarn 2: Discontinuous reinforcing fiber for mixed yarn 3: thermoplastic matrix fiber for wound coating 4: yarn for thermoplastic composite of the present invention

Claims (2)

(57) [Claims] 1. A thermoplastic composite yarn comprising a non-twisted discontinuous thermoplastic matrix fiber, a non-twisted discontinuous reinforcing fiber, and a thermoplastic matrix fiber having a lower melting point than the discontinuous thermoplastic matrix fiber. ,
A blended yarn obtained by blending the discontinuous thermoplastic matrix fiber and the discontinuous reinforcing fiber at a blending degree of at least 20% is added in an amount of 1% by weight or more to 10% by weight with respect to the thermoplastic composite yarn.
A thermoplastic composite yarn, which is wound-coated with the thermoplastic matrix fiber in an amount of not more than 10% by weight. 2. The thermoplastic composite yarn 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.