JPH02160509A - Production of fiber reinforced composite - Google Patents

Abstract

PURPOSE:To enhance strength of the fiber reinforced composite in the bending direction, the width direction and the thickness direction respectively by holding the mixed composition of powdery thermoplastic resin and a fine fibrous filler between the filaments of roving-shaped reinforced fiber and heating them at the temp. not lower than m.p. of resin and thereafter cooling them. CONSTITUTION:Reinforced fiber 1 is guided by the guide rolls 22, 23, 24 and introduced into a vessel 20. The mixed composition 2 of powdery thermoplastic resin and a fine fibrous filler in the vessel 20 is held between filaments. In this case, when a fluidized bed 26 is formed by ejecting gas into the vessel 20 through the air holes 25, the mixed composition 2 can be easily infiltrated into the filaments of reinforced fiber 1. Successively, reinforced fiber 1 holding the mixed composition 2 is supplied to a far infrared heating oven 60 and heated and resin is melted. Thereafter, melted resin is pressed from the upper and lower sides by the heating rollers 61 and thereby melted resin, the fine fibrous filler and reinforced fiber 1 are integrated together. Then when this integrated body is passed through the pinch rolls 11 and cooled, after reinforced composite having a thin belt-shaped prepreg form is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a fiber reinforced composite material in which reinforcing fibers and a thermoplastic resin are integrated.

(Prior technology) Continuous reinforcing fibers in the form of roving are passed through a powdered thermoplastic resin, the reinforcing fibers retain the powdered thermoplastic resin, and then continuously passed through a heating zone to form a powder. A method for producing fiber reinforced composite materials in which reinforcing fibers and thermoplastic resin are integrated by melting a thermoplastic resin is widely known (Japanese Patent Publication No. 52-3985, Japanese Patent Application Laid-Open No. 1983-1999).
-501943, JP-A-63-27208).

(Problem R to be solved by the invention) The fiber-reinforced composite materials obtained by these methods have excellent properties in the bending direction of the fibers because the filaments of the reinforcing fibers are aligned in one direction. Although it shows strength, the strength in the interfiber direction, that is, the width direction and thickness direction of the fiber reinforced composite material is insufficient, and there is a drawback that cracking and elongation along the longitudinal direction of the fibers are likely to occur.

The present invention is intended to solve the above-mentioned drawbacks, and its purpose is to have the filaments of reinforcing fibers aligned in one direction and have high strength in the bending direction, as well as high strength in the width and thickness directions. It is an object of the present invention to provide a method for manufacturing a fiber reinforced composite material that does not cause cracks or the like along the longitudinal direction of the fibers.

(Means for Solving the Problems) The method for producing a fiber-reinforced composite material of the present invention consists of a large number of continuous filaments in a mixed composition of a powdered thermoplastic resin and a fibrous microfiller. After passing the mixed composition through roving-shaped reinforcing fibers and holding the mixed composition between the filaments, this is heated to a temperature higher than the melting temperature of the thermoplastic resin,
It is then characterized by cooling, thereby achieving the above object.

FIG. 1 shows an example of a manufacturing apparatus used in the present invention.

This manufacturing device includes an unwinding roll 10 in which a roll 1a wound with roving-shaped reinforcing fibers 1 is set, and a container in which a mixed composition 2 of a powdery thermoplastic resin and a fibrous microfiller is supplied. 20 and the reinforcing fiber 1 that has passed through the container 20
a pinch roll 11 that takes off the reinforcing fibers 1; a press roll 40 that is disposed in the middle of the reinforcing fibers 1 being taken off by the pinch rolls 11 and presses the reinforcing fibers 1 to spread the reinforcing fibers 1 to a predetermined width; A pair of slitters 50 are disposed on the upper and lower surfaces of the reinforcing fibers 1 to remove excess mixed composition 2 of powdered thermoplastic resin and fibrous microfiller retained on reinforcing fibers 1 to keep the retained amount constant. .51, a far-infrared heating furnace 60 that melts the mixed composition 2 held on the reinforcing fibers 1, and a heating roll 61 that presses the heated mixed composition 2 to integrate it with the reinforcing fibers 1. We are prepared.

A large number of ventilation holes 25 are provided at the bottom of the container 20, and the gas sent from the gas supply path 21 is sent into the interior of the container 20 through the ventilation holes 25. Therefore, the mixed composition 2 placed in the container 20 becomes fluidized by the jetting of the gas, and the fluidized bed 26
is formed. At the upper end and inside the wall of the container 20, there are guide rolls 22, 23, 24 for guiding the reinforcing fibers 1.
is installed.

Next, the manufacturing method of the present invention will be explained using the above manufacturing apparatus.

The ends of the reinforcing fibers 1 are held between pinch rolls 11, and as the pinch rolls 11 are driven, the reinforcing fibers 1 are taken off at a predetermined speed and sequentially rewound from the outside of the rolls 1a without being twisted. The reinforcing fibers 1 are guided by guide rolls 22, 23, 24 into the container 20. A mixed composition 2 of a powdered thermoplastic resin and a fibrous microfiller is placed in the container 20, and the mixed composition 2 enters between the filaments of the reinforcing fibers l passing through the container 20 and is retained. be done. In particular, as described above, by ejecting gas from the vent hole 25 into the container 20 to form the fluidized bed 26, the reinforcing fibers 1 become filament-like due to the ejection of the gas and the collision of the mixed composition 2. The fibers are easily opened, and the mixed composition 2 can easily penetrate between the filaments of the reinforcing fibers 1.

Further, the reinforcing fibers 1 may be mechanically opened within the container 20 using a reinforcing fiber 1 opening device or the like.

Next, the reinforcing fibers 1 holding the mixed composition 2 are passed through a roll 40 while being pressed, and are spread out into a belt shape of a constant width.
．． Excess mixed composition 2 is removed when passing through the upper and lower surfaces of 51, and the amount retained is kept constant. Subsequently, the reinforcing fiber 1 holding the mixed composition 2 is supplied to a far-infrared heating furnace 60, where it is heated to melt the powdery thermoplastic resin.

Thereafter, when passing through the heating roll 61, the molten thermoplastic resin is pressed from both upper and lower surfaces, and as a result, this molten resin is pushed toward the reinforcing fibers 1 and the fine filler, and the molten resin and the fibrous fine filler are and reinforcing fibers 1 are integrated. Next, by passing through pinch rolls 11 and cooling, a fiber-reinforced composite material is obtained in the form of a ribbon-like prepreg.

Roving-shaped continuous reinforcing fiber 1 used in the present invention
Inorganic fibers such as glass fibers, carbon fibers, and fine metal wires, and organic fibers such as aramid fibers, polyester fibers, and polyamide fibers are used, and the fiber diameter is usually 2 to 40μ.
It is a continuous fiber composed of several hundred to several dozen m filaments bundled in the same direction. Further, the reinforcing fibers I may be subjected to a commonly performed sizing treatment in order to improve the adhesive strength with the resin. In addition, fibers are selected that are thermally stable at the melting temperature of the powdered thermoplastic resin used.

Powdered thermoplastic resins used in the present invention include polyethylene, polypropylene, polyvinyl chloride, polysulfone,
All resins that are softened and melted by heat, such as polyamide, polyvinylidene fluoride, polyphenylene sulfide, and polyetheretherketone, can be used. Mixtures of these thermoplastics may also be used. Additives such as stabilizers, lubricants, processing aids, plasticizers, dyes, and pigments may be incorporated into the thermoplastic resin. The average particle diameter of this powdery thermoplastic resin is preferably 1000 μm or less.

If the average particle size of the powdered thermoplastic resin exceeds 1000 μm, the powder will not flow properly in the fluidized bed, making it difficult to adhere the thermoplastic resin between the filaments of the roving-like continuous reinforcing fibers. There is a tendency.

The fibrous microfillers used in the present invention include glass fibers,
Milled inorganic fibers such as carbon fibers, or whiskers such as silicon nitride, silicon carbide, potassium titanate, etc. are preferably used. The average aspect ratio (L/D) of this fibrous microfiller is preferably 5 or more. When the average aspect ratio is less than 5, the fiber-like function is lost, and the fiber-reinforced composite material cannot have sufficient strength in the width and thickness directions. Moreover, the fiber length of the fibrous microfiller is preferably in the range of 10 to 1000 μm. Fiber length is 100
If it exceeds 0 μm, the powder will not flow properly in the fluidized bed 26, and the fibrous microfiller will not adhere sufficiently between the filaments of the roving-shaped reinforcing fibers 1.

If it is less than 10 μm, it loses its fibrous function, and the fiber-reinforced composite material cannot have sufficient strength in the width and thickness directions.

Further, the fibrous microfiller is preferably contained in the mixed composition 2 of the powdered thermoplastic resin and the fibrous microfiller in a range of 1 to 30% by volume. If it is less than 1% by volume,
Because the effect of adding the fibrous microfiller is small, sufficient strength in the width and thickness directions of the fiber-reinforced composite material cannot be obtained;
If it exceeds the volume %, the bonding strength of the thermoplastic resin decreases, and the impregnation of the thermoplastic resin into the reinforcing fibers 1 tends to be impaired.

Air is normally used as the gas for forming the fluidized bed 26, and is supplied from a compressor, blower, or the like. An inert gas such as nitrogen, carbon dioxide, helium, or argon is used as necessary.

In addition, as another manufacturing method of the present invention, the reinforcing fiber 1 holding the mixed composition 2 is placed in a mold having a slit of a desired shape and heated to a temperature equal to or higher than the melting temperature of the powdered thermoplastic resin. By passing, the molten resin, the fine filler, the mixed composition 2, and the reinforcing fibers 1 may be integrated, and a long fiber-reinforced composite material having a desired cross-sectional shape may be obtained.

The fiber-reinforced composite material obtained by the present invention has reinforcing fibers l
The strength of the reinforcing fiber 1 in the bending direction is high because the filaments constituting it are oriented in one direction in an open state, and the fibrous microfiller is randomly oriented and integrated by the resin, so it is reinforced. There is no crack propagation along the longitudinal direction of the fibers 1, and the strength in the inter-fiber direction, that is, the width and thickness direction of the fiber reinforced composite material is also high.

The fiber-reinforced composite material thus obtained can be molded into various shapes, and can be used alone, in a stack of multiple sheets, or in a stack with other members to make plates, pipes, etc.

(Example) The present invention will be explained in detail below based on examples.

[Material] One glass fiber roving (filament diameter 22 μm, 4400 g/km) was used as the reinforcing fiber. A mixed composition of a powdered thermoplastic resin and a fibrous microfiller was used in the following formulation.

Stearyl alcohol polyolefin wax... 1 part by weight... 1 part by weight Manufacturing conditions> A thin strip-shaped fiber reinforced composite material (
(also called prepreg) was produced.

The container 20 is made of hard polyvinyl chloride.
The above-mentioned mixed composition 2 was put into the container. A fluidized bed 26 was formed by blowing air into the container 20 through the vent hole 25 at the bottom of the container 20 using a compressor.

The pick-up speed of the roving 1 is as follows:
The speed was set at a constant speed of 150 ca+/sin. Heating furnace 6
0 was equipped with an infrared heater whose surface temperature was set to about 340°C. The temperature of the heating roll 61 is 190°C
It was set to

The resulting ribbon-shaped fiber reinforced composite material has a width of approximately 301nfl+
, and the thickness was about 0.5 mm. Further, during continuous production, the fiber-reinforced composite material did not separate in the direction between its reinforcing fibers.

Several sheets of the obtained fiber-reinforced composite material were laminated and press-molded to obtain a unidirectionally reinforced plate with a thickness of 2.0 m. When this reinforced plate was subjected to a bending test and a DuPont impact test, the bending strength was 40 kg/IIw + ”, and the impact strength is 55kg-
It was C11.

11 Materials used> One glass fiber roving (filament diameter 22μ, 4400g/km) was used as the reinforcing fiber. As a mixed composition of powdered thermoplastic resin and fibrous microfiller,
A mixture of the following composition was used.

Nylon-6 (average particle size 80 μm)...90 parts by weight Potassium titanate whiskers (average length 50 μm diameter 1 μl11)...10
Manufacturing conditions for weight> In the same manner as in Example 1, a ribbon-shaped fiber reinforced composite material was manufactured under the following conditions using an apparatus in which a fluidized bed 26 was formed in a container 20. The roving 1 was taken at a constant speed of 150 cm/min by the pinch roll 11. The heating furnace 60 was equipped with an infrared heater whose surface temperature was set to about 380°C. The temperature of the heating roll 61 is 225
It was set at °C.

The obtained ribbon-shaped fiber reinforced composite material had a width of about 40 mm and a thickness of about 0.5 mm. Further, during continuous production, the ribbon-shaped fiber-reinforced composite material did not separate in the direction between its reinforcing fibers.

Several sheets of the obtained fiber-reinforced composite material were laminated and press-molded to obtain a unidirectionally reinforced plate with a thickness of 2.0 trtta, and this reinforced plate was subjected to a bending test and a DuPont impact test.
Bending strength is 55kg/mm'' and impact strength is 65k
It was g-Cffi.

<Materials used> One PAN-based carbon fiber roving filament (diameter 8 μm, number of filaments 6000) was used as the reinforcing fiber. A mixed composition of a powdered thermoplastic resin and a fibrous microfiller was used in the following formulation.

<Manufacturing Conditions> Similarly to Example 1, a ribbon-shaped fiber reinforced composite material was manufactured under the following conditions using an apparatus in which a fluidized bed 26 was formed in a container 20. The roving 1 was taken at a constant speed of 120 cm/sin by the pinch roll 11. The heating furnace 60 was equipped with an infrared heater whose surface temperature was set to about 350°C. The heating roll 61 was set at 200°C.

The obtained ribbon-shaped fiber-reinforced composite material had a width of about 20 mm and a thickness of about 0.5 days. Further, during continuous production, the fiber-reinforced composite material did not separate in the direction between its reinforcing fibers.

Several sheets of the obtained fiber-reinforced composite material were laminated and press-molded to obtain a unidirectionally reinforced plate with a thickness of 2.0 am. When this reinforced plate was subjected to a bending test and a DuPont impact test, the bending strength was 65 kg/+vm. ”, and the impact strength is 65kg-
It was cta.

Comparison 1 ■ <Materials used> One PAN-based carbon fiber roving filament (diameter: 8 μm, number of filaments: 6000) was used as the reinforcing fiber. A mixed composition of a powdered thermoplastic resin and a fibrous microfiller was used in the following formulation.

(Leaving space below) Butyltin sulfur-containing stabilizer: 3 parts by weight Stearyl alcohol: 1 part by weight Polyolefin wax: 1 part by weight <Manufacturing conditions> As in Example 1, a fluidized bed was placed in the container 20. A ribbon-shaped fiber-reinforced composite material was manufactured using the apparatus in which No. 26 was manufactured under the following conditions.

The roving l was taken at a constant speed of 120 cm 10+in by the pinch roll 11. The heating furnace 60 had an infrared heater set at a surface temperature of about 350''C. The heating roll 61 was set at 200°C.

The resulting thin strip-shaped fiber-reinforced composite material has a width of about 30 plates and a thickness of about III! It was i. In addition, the fiber-reinforced composite material developed cracks that split along the fiber direction of the reinforcing fibers during continuous manufacturing.

Several sheets of the obtained fiber-reinforced composite material were laminated and press-molded to a thickness of 2. A unidirectional reinforced plate of Orm was obtained, and this reinforced plate was subjected to a bending test and a DuPont impact test, and the bending strength was 15 kg/mm'' and the impact strength was 5 kg-c.

(Effects of the Invention) As described above, according to the manufacturing method of the present invention, the reinforcing fiber filaments are aligned in one direction and have high strength in the bending direction, and in addition, the fine filler is not oriented and can be used together with the thermoplastic resin. It is possible to obtain a fiber-reinforced composite material that is integrated, has high strength in the width direction and thickness direction, and does not cause cracks or the like along the longitudinal direction of the fibers.

Figure 1 is a schematic diagram showing an embodiment of the manufacturing apparatus used in the present invention.

1... Reinforcing fiber, 2... Mixed composition.

that's all

Claims (1)

[Claims] 1. A roving-shaped reinforcing fiber composed of a large number of continuous filaments was passed through a mixed composition of a powdered thermoplastic resin and a fibrous microfiller to hold the mixed composition between the filaments. A method for producing a fiber-reinforced composite material, which comprises heating the material to a temperature higher than the melting temperature of the thermoplastic resin, and then cooling the material.