JP3241435B2 - Fiber-reinforced thermoplastic resin composite material and method for producing the same - 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 material and a molding material using a thermoplastic resin as a matrix.

[0002]

2. Description of the Related Art Conventionally, fiber-reinforced composite materials having a thermosetting resin as a matrix have been mainly used for various molding materials. However, fiber-reinforced composite materials using a thermoplastic resin as a matrix have attracted attention from the viewpoints of toughness, storability and recyclability, and have been actively developed in recent years. However,
Since thermoplastic resins generally have a high melt viscosity and are difficult to impregnate reinforcing fibers, various methods are being developed.
For example, there are a mixed fiber method in which a thermoplastic resin is fiberized and uniformly mixed with reinforcing fibers, and a method in which a thermoplastic resin powder is dispersed between reinforcing fibers. However, in these cases, it is necessary to melt-impregnate the thermoplastic resin during molding,
The molding time is long, and it is necessary to increase the molding pressure.

On the other hand, various methods for directly impregnating with a molten thermoplastic resin have been developed. In this case, the resin is melted by an extruder, supplied to a die, and in order to impregnate the reinforcing fibers therein, a projection is provided in the die, or a pin is provided, and the reinforcing fibers are passed along the same, and squeezed. There is a method of impregnation. However, since the viscosity of the molten resin is high, the take-up tension of the impregnated fiber reinforced composite material is increased, and it is difficult to improve the production speed. For this reason, a method of lowering the melt tension of the thermoplastic resin to facilitate the impregnation and at the same time lowering the take-up tension is used in combination.

[0004]

In the above impregnation in a die, a flame retardant, an antistatic agent, a release agent,
To prepare various grades by adding additives such as lubricants, crystallization accelerators, antioxidants, ultraviolet absorbers, heat stabilizers, and pigments, and to prepare grades with different contents of reinforcing fibers , Extruder and die cleaning or die replacement,
It is necessary to replace the shaping die at the die outlet, which lowers the operation rate and lowers productivity. On the other hand, when the melt viscosity is reduced, the impregnation becomes easier and the productivity is improved, but there is a problem that the physical properties of the obtained fiber-reinforced composite material are apt to be lowered.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present invention has been completed. That is, the present invention relates to a method in which one or more tape-like fiber-reinforced thermoplastic resin composite materials having a flatness of 5 or more, in which continuous reinforcing fibers are impregnated with a first thermoplastic resin, are bundled with the first thermoplastic resin. A fiber-reinforced thermoplastic resin composite material characterized by being coated and integrated with the same second thermoplastic resin, and the molecular weight of the first thermoplastic resin in the fiber-reinforced thermoplastic resin composite material. Is a fiber-reinforced thermoplastic resin composite material characterized by having a lower molecular weight than the second thermoplastic resin, further, in the fiber-reinforced thermoplastic resin composite material, the first thermoplastic resin, especially an additive A fiber-reinforced thermoplastic resin composite material characterized by containing an additive in the second thermoplastic resin without containing the additive. Further, a continuous thermoplastic fiber is impregnated with a first thermoplastic resin to produce a tape-like fiber-reinforced thermoplastic resin composite material having an aspect ratio of 5 or more, and after bunching one or more tapes, the first thermoplastic resin and The method for producing a fiber-reinforced thermoplastic resin composite material according to the above, characterized in that the fiber-reinforced thermoplastic resin composite material is coated and integrated with substantially the same second thermoplastic resin.

Hereinafter, the present invention will be described in detail. Examples of the reinforcing fibers used in the present invention include continuous fibers such as glass fibers, carbon fibers, aramid fibers, ceramic fibers, metal fibers, and fibers obtained from heterocyclic-containing polymers such as polybenzothiazole and polybenzoxazole. These may be used in combination of two or more, and it is preferable that a surface treatment for improving the adhesion with the thermoplastic resin to be used is performed. The number of these reinforcing fibers is 50 to 2000 per strand.
0, preferably 200 to 12,000. on the other hand,
Examples of the thermoplastic resin include polyethylene, polypropylene, polyolefins including copolymers and modified products thereof, polyamides such as nylon 6, nylon 66, and nylon 12, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, and thermosetting resins. Examples include plastic polyurethane, polyetherimide, polyphenylene sulfide, and polyether ketone. The reinforcing fiber and the thermoplastic resin are not particularly limited to these.

[0007] Various known methods can be used for impregnating the continuous reinforcing fibers with the first thermoplastic resin.
For example, an example in which a convex die and a linear die as shown in FIG. 1 are combined is effective for efficient impregnation. In this case, the reinforcing fibers are continuously supplied to the convex die, the reinforcing fibers are partially impregnated with the resin by the convex die, and then further impregnated by the linear die. After that, a compression means such as a roll for improving impregnation may be provided. In this case, the impregnation state is preferably better, but not necessarily perfect. As the evaluation of the impregnation state, it is simple and preferable to cut the obtained impregnated material into a length of about 10 mm, immerse the same in water, and evaluate the weight increase ratio before and after the immersion. The value measured by this evaluation method is called a porosity, and the value is preferably 15% or less, more preferably 8% or less. This value is 15
%, The physical properties of the finally obtained composite material are unfavorably low. When it is about 15%, the impregnation is slightly improved when the coating and integration with the second thermoplastic resin is performed, and the level is no problem. The impregnated fiber-reinforced thermoplastic resin composite material is preferably in the form of a tape having an aspect ratio of 5 or more. This is because such a shape is excellent in handleability and impregnation. In particular, winding is easy, space efficiency is high at the time of storage, and it is easy to provide for the next step. Here, the flatness is the width / thickness of the tape. The width of the tape is preferably 1 to 30 mm, more preferably 2 to 1 mm.
5 mm. If the flatness and the width are out of the range, winding becomes difficult or the winding amount is limited, and it is difficult to efficiently integrate the second thermoplastic resin into the coating in the next step. Further, the reinforcing fiber content of the tape-like fiber-reinforced thermoplastic resin composite material is preferably 50 to
It is 80% by volume, more preferably 60 to 75% by volume.
Here, the fiber content is preferably high, and the desired fiber content can be easily obtained by coating and integrating the second thermoplastic resin later. If the reinforcing fiber content of the tape-shaped fiber-reinforced thermoplastic resin composite material is less than 50% by volume, the degree of freedom of changing the reinforcing fiber content is reduced by the subsequent integration of the second thermoplastic resin by coating, and the overall As a result, only a product having a low reinforcing fiber content can be obtained. On the other hand, when the content exceeds 80% by volume, the reinforcing fibers cannot be uniformly impregnated and good products cannot be obtained. On the other hand, the first thermoplastic resin preferably has a lower molecular weight than the second thermoplastic resin, that is, has a low melt viscosity and excellent impregnation. Further, as the first thermoplastic resin, a modified thermoplastic resin may be used so as to have excellent adhesion to the reinforcing fiber. For example, when polypropylene is used as the thermoplastic resin, the first thermoplastic resin is a maleic acid-modified polypropylene, while the second thermoplastic resin has a higher molecular weight than the first polypropylene, that is, the melt viscosity is higher. And the case where a homopolypropylene is used. Furthermore, additives such as a flame retardant, an antistatic agent, a release agent, a lubricant, a crystallization accelerator, an antioxidant, an ultraviolet absorber, a heat stabilizer, and a pigment may be added to the second thermoplastic resin according to the purpose. Can be added. In this case, it is preferable that the first thermoplastic resin does not particularly contain an additive. Because it was previously impregnated with the first thermoplastic resin,
A fiber-reinforced thermoplastic composite material with the same grade of tape-like fiber-reinforced thermoplastic resin material produced at high speed, stocks held, and a second thermoplastic resin coated and integrated to provide various functions Can be efficiently produced at high speed.

[0008] Such a second thermoplastic resin is converted into a first thermoplastic resin.
As a means for coating and integrating into a tape-like fiber reinforced thermoplastic resin composite material impregnated with a thermoplastic resin, for example, a die for wire coating is attached to the tip of a normal extruder, and one tape is attached to the die. Preferably two or more, supply the desired number of tape-shaped fiber reinforced thermoplastic resin composite material bundled,
A method of coating and integrating with a second thermoplastic resin is given. Here, it is preferable that the number of bundles of the tape is supplied so as to match a desired cross-sectional area. At this time, it is necessary to determine the cross-sectional area in consideration of the amount of the second thermoplastic resin and the final fiber content. The final fiber content can be controlled by the cross-sectional area of the exit shaping nozzle of the die, and the final shape is also round,
It can be controlled by the shape of the exit shaping nozzle, such as corners and irregular shapes. The step of coating and integrating in this manner is much simpler than the impregnation step, and the processing speed can be extremely high. Further, the porosity of the composite material obtained here is preferably 10% or less, more preferably 8% or less. The fiber-reinforced thermoplastic resin composite material thus obtained can be used for, for example, concrete reinforcing bars, geogrids, tension members, and the like. It can also be used as a molding material.

[0009]

According to the present invention, for example, a tape-like fiber-reinforced thermoplastic resin composite material impregnated with a first thermoplastic resin is made of the same grade, that is, a resin containing no particular additive, and has a fiber content of 50 to 50%. High volume of 80% by volume is produced and stocked in large quantities. This allows efficient production of a multipurpose, multi-product fiber-reinforced thermoplastic resin composite material without switching the resin at the impregnation die or switching the fiber content. Moreover, in this step, it is not necessary to completely impregnate, and therefore, the production speed is relatively easily improved. Further, since it is in the form of a tape, it can be wound up, is easy to be provided for the next step, and requires little space for storage. Thereafter, when the tape is coated and integrated with the second thermoplastic resin, it is possible to easily add an additive and to change the fiber content, and it is possible to cope with various grades. Further, as an attendant effect, it is possible to eliminate fluff and the like on the surface of the obtained composite material and improve the surface properties.
Moreover, since this step is for coating and integrating, it is possible to dramatically improve the processing speed. Furthermore, in this step, the impregnation is improved to some extent by passing through the shaping die, and the dispersion of the reinforcing fibers in the obtained composite material is also improved. However, these depend on the processing speed of coating integration, the pressure in the coating die, and the like, and it is preferable to determine the conditions according to the required characteristics of the composite material.

Further, in the present invention, a resin having a low molecular weight, that is, a resin having a low melt viscosity can be used as the first thermoplastic resin, and at the same time, a resin having excellent adhesion to the reinforcing fiber can be used. Thus, the impregnation can be performed more quickly, and the production speed of the impregnation step can be improved. Furthermore, the adhesiveness with a reinforcing fiber is also excellent. Moreover, the second thermoplastic resin having a higher molecular weight than the first thermoplastic resin is used.
Since it is coated and integrated with a thermoplastic resin, it is possible to maintain physical properties as a composite material at a satisfactory level.

[0011]

According to the present invention, a fiber-reinforced thermoplastic resin having various functions can be efficiently produced at a high speed.
In particular, it can respond to production of many kinds and small lots very quickly. Further, since each process can be performed at a relatively high production speed, the efficiency as a whole can be improved. Further, a material having high physical properties as the obtained composite material is obtained.

[0012]

Example 1 As reinforcing fibers, glass fibers having a single yarn diameter of 17 μm, a number of filaments of 2,000 and 1,150 tex, and treated with aminosilane and a modified olefin were used. As the first thermoplastic resin, 0.2% by weight maleic acid-modified polypropylene was used. The melt flow index (MF) of this polypropylene
I) is 60 g / 10 min (ASTM D-1238). One glass fiber strand was impregnated with a die as shown in FIGS. 1 and 2 to have a width of 3.8 mm and a thickness of 0.2.
mm, a tape having a fiber content of 60% by volume was produced and wound at a speed of 60 m / min. The resulting tape has a flatness of 19,
The porosity was 8%. As the second thermoplastic resin, a homopolypropylene (MFI = 10 g / 10 min) having a higher molecular weight than that of the first thermoplastic resin was used. This coating was integrated, and the diameter of the fiber was 20% by volume (40% by weight).
A 5 mm rod was obtained. Processing speed of coating integration is 150m
/ Min, and the porosity of the obtained composite material was 5%. This rod was cut into a length of 10 mm to obtain a pellet. The pellet was subjected to injection molding. The molding machine has a mold clamping force of 100
Ton, screw diameter 32 mm, L / D 21.6, compression ratio (depth ratio) 2.26 were used. The obtained molded product is designated as A
Evaluation was performed according to STM. Izod impact value is 48kg
-Cm / cm.

[0013]

Example 2 In the tape obtained in Example 1, the second
In the same manner as in Example 1, coating and integration were performed using a polypropylene blended with 0.2% by weight of carbon black and having an MFI of 10 g / 10 minutes as a thermoplastic resin. When injection molding was performed in the same manner as in Example 1, there was no color spot on the molded product.

[0014]

Comparative Example 1 In the same manner as in Example 1, a wire having a flatness of 1.0 and a diameter of 1 mm was obtained instead of the tape. However, since this wire is difficult to wind, it was impossible to manufacture and stock it in large quantities.

[0015]

Comparative Example 2 Two glass fibers of Example 1 were passed through a die in which three pins each having a diameter of 10 mm were set in an impregnating die to perform impregnation. As the thermoplastic resin, 0.2% by weight maleic acid-modified MFI = 10 g / 10 min. Polypropylene was used. The production speed was limited to 10 m / min, and when the speed was further increased, the glass fiber was cut. The production speed was 10 m / min, the reinforcing fiber content was set to 20% by volume (40% by weight), and a rod-shaped composite material having a diameter of 2.5 mm was obtained. Had considerable fluff. This was cut into a length of 10 mm, injection molded in the same manner as in Example 1, and evaluated. However, at the time of molding, a bridge was formed by the hopper due to the fluff, making molding difficult, and the measuring time (plasticizing time) required 25 seconds, which was about twice that of Example 1. The Izod impact value of the obtained molded product was 32 kg · cm / cm.

[0016]

Comparative Example 3 The same procedure was performed as in Comparative Example 2 except that the resin of Comparative Example 2 was changed to MFI = 60 g / 10 minutes. Production speed is 20
m / min. The porosity of the obtained composite material was 6%. The fluff on the surface was considerably less than that of Comparative Example 2, and injection molding was performed without any problem. The Izod impact value of the obtained molded product was 30 kg · cm / cm.

[0017]

Comparative Example 4 In Example 1, the first resin was changed to MFI =
MFI = 60 g was used as the second resin using a polypropylene modified with 0.2% by weight of maleic acid at 10 g / 10 min.
The procedure was performed in the same manner as in Example 1 except that a homopolypropylene of / 10 min was used. The porosity of the tape was 19% and the porosity of the round bar composite was 16%. The result of the injection molding was an Izod impact value of 27 kg · cm / cm. This is probably because the impregnation was poor and the glass fibers were damaged by the screw during injection molding.

[Brief description of the drawings]

FIG. 1 is a schematic view of one embodiment showing a form of a die impregnated with a first thermoplastic resin of the present invention.

FIG. 2 is a schematic view of each apparatus in one embodiment of a step of impregnating a first thermoplastic resin of the present invention.

FIG. 3 is a schematic view of each apparatus in one embodiment of a step of coating and integrating a tape with a second thermoplastic resin of the present invention.

FIG. 4 is a schematic sectional view schematically showing a composite material of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Impregnation die 2 Convex die 3 Straight die 4 Outlet nozzle block 5 Resin discharge port 6 Outlet nozzle 7 Extruder 8 Reinforcing fiber bobbin 9 Opening bar 10 Compression cooling nip roll 11 Puller 12 Winder 13 Guide roll 14 First thermoplasticity Tape impregnated with resin 15 Wounded tape impregnated with first thermoplastic resin 16 Die for covering and integrating tape with second thermoplastic resin 17 Cooling water tank 18 Pelletizer 19 Pellet 20 Reinforcing fiber 30 Heat Plastic composite material 40 First thermoplastic resin 50 Second thermoplastic resin

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29B 11/16 B29B 15/08-15/14 B29C 70/06

Claims (4)

(57) [Claims] What is claimed is: 1. A continuous reinforcing fiber directly impregnated with a first thermoplastic resin by a melt impregnation method, wherein at least one tape-like fiber-reinforced thermoplastic resin composite material having an aspect ratio of 5 or more is bundled.
A fiber-reinforced thermoplastic resin composite material characterized by being covered and integrated with a second thermoplastic resin that is substantially the same as the first thermoplastic resin. 2. The method according to claim 1, wherein the molecular weight of the first thermoplastic resin is lower than the molecular weight of the second thermoplastic resin.
The fiber-reinforced thermoplastic resin composite material according to the above. 3. A particular free of additives to the first thermoplastic resin, fiber-reinforced thermoplastic resin composite according to claim 1 or 2 characterized in that it comprises an additive to the second thermoplastic resin material. 4. A continuous reinforcing fiber is impregnated with a first thermoplastic resin to produce a tape-like fiber-reinforced thermoplastic resin composite material having an aspect ratio of 5 or more.
Claims 1-3 Izu by the thermoplastic resin substantially identical to the second thermoplastic resin, wherein the covering integrated
The method for producing a fiber-reinforced thermoplastic resin composite material according to claim 1.