JPH04183729A - Molding material for thermoplastic composite - Google Patents

Abstract

PURPOSE:To obtain the subject lightweight tough material, composed of a yarn unit, containing specific thermoplastic organic filament and reinforcing filament and having a specified degree of combined filaments or a woven fabric, etc., constructed from the aforementioned yarn unit, excellent in surface smoothness and useful for molding thermoplastic composites. CONSTITUTION:The object material is composed of a yarn unit prepared from (A) thermoplastic organic filament (e.g. filament of nylon 66 or polyethylene) having 0-0.8 structure integrity parameter of the aforementioned organic filament and <=5% dry heat shrinkage factor at a temperature of (melting point -80 deg.C) and (B) reinforcing filament (e.g. glass or carbon fiber) according to a lapping method, etc., so as to provide >=20% degree of combined filaments or a woven, a knitted or a multiple axis laminated fabric constructed from the above- mentioned yarn unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a molding material for a thermoplastic composite, which is composed of a filament obtained by mixing reinforcing continuous fibers and thermoplastic organic continuous fibers.

(Prior art) A molding material for thermoplastic composite gutter, which is a mixture of reinforcing continuous fibers and thermoplastic organic continuous fibers, is disclosed in Japanese Patent Application Laid-open No. 60-20
As disclosed in Japanese Patent Application Laid-open No. 9034 and Japanese Patent Application Laid-Open No. 61430345, so-called ordinary drawn yarns are usually used as thermoplastic organic continuous fibers, and these conventional molding materials have sufficient yarn strength. and has appropriate elongation.

However, when molding is performed using these conventional molding materials, there are drawbacks such as irregularities in the amount of matrix in the longitudinal direction, insufficient impregnation, and uneven impregnation, and the resulting molded products lack toughness. Ta.

There was also the problem that it was not possible to obtain a molded article with an excellent surface condition.

Furthermore, in order to obtain a so-called ordinary drawn yarn, it is necessary to ensure process passability. Therefore, it is necessary to apply a large amount of a surface treatment agent (spinning oil, etc.), which causes problems such as a decrease in the strength of the interface between the reinforcing fibers of the molded article and the matrix. Of course, the manufacturing cost was also high.

(Problems to be Solved by the Invention) An object of the present invention is to provide a molding material for thermoplastic composites that is lightweight, strong, and useful for molding thermoplastic composites with excellent surface smoothness.

A thermoplastic composite molding material in which reinforcing continuous fibers and thermoplastic organic continuous fibers are mixed can be subjected to heat press molding or the like to produce molded products with complex curved surfaces. It is also used in pultrusion methods, filament winding methods, etc.

In any manufacturing process, it is necessary to heat the thermoplastic composite molding material, melt the thermoplastic organic continuous fibers, and sufficiently impregnate the reinforcing continuous fibers.

At that time, if the difference in thermal behavior between the reinforcing continuous fibers and the thermoplastic organic continuous fibers and the degree of blending of the composite molding material are not appropriate, the two fibers may separate immediately before or during melting, or the thermoplastic organic continuous fibers may Instant cutting of continuous fibers (
(fuse breakage) occurs, making it impossible to obtain a good impregnated state.

(Means for Solving the Problems) That is, the present invention provides a thread body containing thermoplastic organic continuous fibers and reinforcing continuous fibers with a blending degree of 20% or more, or a fabric made of the thread body. , a knitted fabric or a multiaxially laminated fabric, in which the structural integrity parameter of the thermoplastic organic continuous fiber is 0 or more and 0.8 or less, and the dry heat shrinkage rate of the organic continuous fiber at a melting point of -80°C is 5. % or less.

Here, the structural integrity parameter (ε) is defined by the following formula.

■、−■.

1°1°: Length of the sample before heat treatment 11: The length of the sample after heat treatment is measured by the following method. Apply an initial load of 0.2 g/d to the sample and measure 10. Thereafter, the sample was immersed in water at 80° C. for 2 minutes, and then 11 was measured.

The dry heat shrinkage rate is a value measured by the dry heat shrinkage rate B method of JIS-L-1013. However, the temperature at the time of measurement is set to -80''C, which is the melting point of the thermoplastic continuous fiber.

If measurement cannot be performed at a temperature of -80°C, the melting point is changed, then the temperature at the time of measurement is changed and extrapolation is performed from those values.

Further, the degree of blending is defined by the following formula.

Here, N indicates the total number of reinforcing continuous fibers, NcX indicates the number of groups when the reinforcing continuous fibers are divided into several groups (C groups), and X indicates the number of specific reinforcing fibers in the group. The number of filaments in one section is shown.

In the above two, 100X (N-X) / (N-
1) means a mixed fiber state, and the smaller X is, the better the mixed fiber state is. Further, Nc-X/N/X is a weight.

In the actual process, heat and pressure are applied to the thermoplastic composite molding material, so that the thermoplastic organic continuous fibers are melted and impregnated with reinforcing continuous fibers, and after a cooling process, a composite is formed. The melt state of the thermoplastic organic continuous fibers is a factor that controls the physical properties and appearance of the composite. That is, it is necessary to reduce the amount of shrinkage and shrinkage force during melting. By achieving this state, it is possible to impregnate the reinforcing continuous fibers without disturbing their parallelism, and the resulting composite exhibits its physical properties to the fullest and has an excellent appearance.

Of course, the melt viscosity of the thermoplastic organic continuous fiber is also an important factor, and it is necessary to optimize it within the specified ranges of the structural integrity parameters, dry heat shrinkage rate, and blending degree of the present invention.

As a surface treatment agent for thermoplastic organic continuous fibers, so-called spinning oil is generally applied to maintain passability in the fiber manufacturing process and subsequent processes.

It is preferable not to use this type of treatment agent as much as possible since it inhibits the adhesive force between the reinforcing fibers of the composite and the matrix interface.

The thermoplastic organic continuous fibers used in this invention include:
Examples include polyamide fibers such as nylon 6 and nylon 66, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, polyolefin fibers such as polyethylene and polypropylene, polyphenylene sulfide fibers, and polyether ether ketone fibers.

However, the thermoplastic organic continuous fibers used in this invention are not limited to the above fibers.

It is also effective to use crimped thermoplastic organic continuous fibers for the purpose of facilitating fiber blending. This is because the single fibers have crimps, which reduces the contact between the single fibers and reduces the apparent H vibration force between the fibers, making it easier to open the fibers. Examples of methods for imparting crimp include imparting the ability to develop crimp during spinning, or imparting crimp after fiber formation.

Furthermore, examples of the reinforcing continuous fibers used in the present invention include glass fibers and carbon fibers.

However, the reinforcing continuous fibers used in this invention are not limited to the above-mentioned fibers.

The reinforcing continuous fibers and thermoplastic organic continuous fibers may be mixed by any method such as a gas blowing method, an electric opening method, or a wrapping method, but the mixing degree is 2.
It is preferably 0% or more.

As an example of a preferable fiber blending method, after making the width of the thermoplastic organic continuous fiber bundle A wider than the width of the reinforcing continuous fiber bundle B, A and B are guided to a guide plate having a concave surface, and A
An example of this method is to overlap S so that S is in contact with a guide plate, wrap B so that it is introduced into a fluid nozzle, and mix the fibers.

However, it is not limited to this. This method will be further explained. An example of the method is shown in FIG.

The reinforcing continuous fiber bundle and the thermoplastic organic continuous fiber bundle are guided to a fiber bundle guide plate having a concave surface as illustrated in FIG.

At this time, it is important to make the width of the thermoplastic organic continuous fiber bundle A wider than the width of the reinforcing continuous fiber bundle B. By doing so, the fiber mixing effect by the fluid nozzle can be made reliable and stable.

Preferably, the width of the fiber bundle A is 20% to 100% wider than the width of the fiber bundle B. By introducing tK A into contact with the guide plate having a concave surface while maintaining the above relationship, the fiber bundle of A is transferred to the fiber bundle of B at the outlet of the guide plate, that is, near the inlet of the fluid nozzle. It can be arranged so as to wrap around the bundle.

By subjecting both fiber bundles having such an arrangement to a blending action using a fluid nozzle as exemplified in FIG. 3, it is possible to produce a stable mixed fiber yarn for a composite with a high degree of blending. It is preferable that the curvature of the concave surface of the guide plate is smaller near the fiber bundle exit than near the fiber bundle entrance. Further, it is preferable that the surface has low frictional resistance with the fiber bundle.

Regarding the structure of the fluid nozzle, compared to the so-called interlace type nozzle, the fluid introduction path is 90% smaller than the yarn path.
Preference is given to nozzles of the type having the following angles: More preferably, the vicinity of the inlet of the fluid nozzle has a tapered circular shape, and the vicinity of the fluid jet has an elliptical or rectangular shape, and the fluid is slint-shaped. It is best to have a shape that allows it to be ejected from the shape path.

Furthermore, it is also possible to have a plurality of fluid ejection paths and slightly change the ejection position to the yarn path, as illustrated in FIG.
This is effective for increasing and stabilizing the degree of blending of the resulting blended yarn.

Regarding the relationship between the width of A and the width of B, the width of B is
If the width is the same as or less than the width of B, it is located on the outside of the mixed yarn where B has low frictional resistance, so it has low resistance to friction in the subsequent process, and it is difficult to cut B. Otherwise, damage may occur, and in some cases, trouble may occur in post-processing steps. Also, even in the case of a composite,
This method has the disadvantage that only low reinforcement efficiency, ie, composites with poor physical properties can be obtained. In addition to it,
The stability of the mixed fiber state of the mixed fiber yarn is also lacking. Therefore, it is essential that the width of A is larger than the width of B, and preferably 20% or more.

Conversely, if the width of A is 100% or more larger than the width of B, the uniform distribution in the 80-width direction will be lost, depending on the volume fraction of A and B, and the fiber mixing efficiency by the fluid nozzle will be reduced. tends to decrease, resulting in a favorable state. Therefore, it is better to make the width of A 100% or less of the width of B.

The width of the thermoplastic organic continuous fiber (A) is changed to the reinforcing continuous fiber (
In the method of making the width wider than B), it is preferable to use a parallel plate static electricity applying device as illustrated in FIG. Figure 5
It is also possible to use a device as exemplified in . It is also possible to use a fluid nozzle for the purpose of fiber opening. As described above, it is also effective to provide crimps to the thermoplastic organic continuous fibers. In this case, for example, a latent crimp ability is imparted to the fiber by applying asymmetric cooling during melt spinning, and this crimp ability is manifested continuously or discontinuously, resulting in so-called three-dimensional crimp. Examples include fibers imparted with crimp properties, or fibers imparted with so-called mechanical crimp properties such as false twisting after melt spinning.

The structural integrity parameter (ε) of the thermoplastic organic continuous fiber of the present invention is 0 or more and 0.8 or less, and the dry heat shrinkage rate is 5%.
It is necessary that the following is true. If within this range,
By the time the fibers are melted, there is little structural change in the molecules, and a smooth molten state is attained in a short time, so that reinforcing fibers can be impregnated without disturbing the alignment of the reinforcing fibers. ε is 0.
8 or more and the dry heat shrinkage rate is 5% or less, this state can be obtained in principle, but during the process, especially in the mixed yarn manufacturing process, knitting, and weaving process, When the fibers are ironed, the organic fibers may be elongated, fluffed, or broken, which imposes considerable practical limitations.

Further, in some cases, the state of the mixed fibers may be reduced in the step after the fibers are mixed, and this may cause a reduction in the state of impregnation, that is, a reduction in the physical properties of the composite.

If the degree of blending is 20% or more, the reinforcing continuous fibers will be impregnated in a short time when melted. On the other hand, if the degree of blending is less than 20%, impregnation will take a long time and will be uneconomical. In addition, the mechanical properties of the molded product deteriorate due to insufficient impregnation.

In this invention, the mixing ratio of reinforcing continuous fibers and thermoplastic organic continuous fibers is not particularly limited;
The weight fraction (Wf) of the reinforcing continuous fibers is preferably in the range of 30 to 80%.

The thermoplastic composite molding material of the present invention is a thread, or a woven fabric, knitted fabric, or multiaxially laminated fabric made of the thread. A preferred example is a multiaxially laminated fabric that is multiaxially laminated and integrated. Multi-axis lamination and integration refers to laminating and integrating multiple layers of threads that are uniaxially oriented and aligned at different angles, for example, 2
Laminated layers of yarn perpendicular to the axis, O/45/90
/-45 in which four oriented yarn layers are laminated. By using a fabric foil-shaped molding material that is multiaxially laminated and integrated, it becomes easy to deform when molding products with various curved surfaces. In this specification, the filament means a yarn composed of a large number of continuous single filaments. Examples of the fabric foil-like material in which multiaxially laminated layers are integrated include knitted fabrics, or knitted fabrics in which uniaxially oriented yarn layers are multiaxially laminated and integrated. Because the threads of fabric foil-shaped molding materials are arranged in straight lines, they can exert a reinforcing effect more effectively than plain woven fabrics. Furthermore, when deep drawing or the like is performed on the molding material, the thread axis between the eyebrows can be easily changed, and the thread spacing within the layer can be widened, so it has the advantage of being easy to shape.

(Examples) The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 One 5,400 denier continuous thread of E glass fiber whose single fiber diameter is 13 μm and which has been surface-treated, and one 2,900 denier continuous thread of polyester fiber whose single fiber diameter is the same, were heated in an air-only system. The fibers were mixed using a nozzle to form a mixed fiber yarn. The polyester fiber used was one obtained by melt-spinning a resin having an intrinsic viscosity of 0.63, winding the fiber at a speed of 3,700 m/min, and then heat-treating the fiber at 220° C. under a fixed length. Processing conditions are speed 250m/min, air pressure 4kg/c.
It was 4. Using the obtained mixed fiber yarn, the fabric weight is 1430g/
A laminated cloth with n:, 4 axes (0°/-451/90'/45°) was created. The Stinoti thread that fixes each layer contains 1
A 50Den-48Fil polyester thread was used. For both polyester fibers, the spinning oil was 0.2%,
Care was taken not to impede adhesion. 150 pieces of this laminated cloth
After drying for 1 hour at a temperature of 290 °C,
Pressurization was carried out for 6 minutes at a pressure of I MPa at ℃, and then 1
It was cooled to 50° C., taken out from the mold, and a laminate was produced. Table 1 shows the properties of this laminate. The bending properties are O
°Measurements were made in the force direction. Bending strength is JIS-70
55. Izod impact strength was measured according to ASTM 256.

Example 2 A laminate was produced in the same manner as in Example 1, and its properties were measured. The results are also shown in Table 1.

However, the heat treatment conditions for polyester fibers are 205℃ under the fixed length.
And so. In addition, the air pressure for the mixed fiber condition was 3.5 kg/c.
It was set as d.

Example 3 A laminate was produced in the same manner as in Example 1, and its properties were measured. The results are also shown in Table 1.

However, the winding speed during melt spinning of polyester fiber is 3.
000 m/min. Further, the conditions for the subsequent heat treatment were 195° C. under constant length.

Comparative Example 1 A laminate was produced in the same manner as in Example 1, and its properties were measured. The results are also shown in Table 1ζ.

However, heat treatment was not performed after the polyester fibers were melt-spun. The amount of the spinning oil applied was 0.6%.

While drying the laminated cloth at 150° C., warping of the cloth due to heat shrinkage of the polyester fibers and disordered distribution of glass fibers were observed. In addition, the glass fibers of the laminate after molding were also found to have a disordered arrangement, and the adhesion between the glass fibers and polyester of the sample was found to be insufficient after Izotsu impact strength measurements were performed using a scanning electron microscope (SE). .

Comparative Example 2 A laminate was produced in the same manner as in Example 1, and its properties were measured. The results are also shown in Table 1.

However, the winding speed during melt spinning of polyester fiber is 13
00 m/min, and then subjected to stretching treatment using a stretching machine. The temperature of the heater at that time was 180°C.

Comparative Example 3 A laminate was produced in the same manner as Comparative Example 2, and its properties were measured. The results are also shown in Table 1.

However, the heater temperature during the stretching process in the stretching machine must be 190℃.
And so.

Table 1 *○: Good adhesion state ×: Poor adhesion state (effects of the invention) The present invention provides a molding material for thermoplastic composites that is useful for molding thermoplastic composites that are lightweight, strong, and have excellent surface smoothness.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention. FIG. 2 shows a guide plate having a concave surface, which is an embodiment of 7 in FIG. 3 is a fluid nozzle, which is an embodiment of 7 in Sono. FIG. 4 shows an electrostatic charge applying device, which is an embodiment of 6 in FIG. Figure 5 shows a meniscal plate with a concave surface for fiber opening, 1i4
This is an embodiment of 6 of 1, and in the figure 1: Package of reinforcing continuous fibers 2: Pancake of thermoplastic organic continuous fibers 3: Tension compensator. 4: Tension compensator 5: Supply roller pair 6: Opening device 7: Guide plate with concave surface 8: Supply roller pair 9: Fluid nozzle
10: Take-up roller pair 11: Winding device 12
: Indicates mixed yarn. Patent applicant: Toyobo Co., Ltd. Keyaki 21! l world 3 diagram

Claims (1)

[Scope of Claims] A thread body containing thermoplastic organic continuous fibers and reinforcing continuous fibers with a blending degree of 20% or more, or a woven fabric, knitted fabric, or multiaxial laminate fabric composed of the thread body, ,
The structural integrity parameter of the thermoplastic organic continuous fiber is 0.
0.8 or less, and the melting point of the organic continuous fiber is -8
A molding material for a thermoplastic composite, characterized by a dry heat shrinkage rate of 5% or less at 0°C.