JPH1199519A - Manufacture of fiber-reinforced composite material and fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the impregnating properties of a resin with a bundle of fibers and significantly increase a haul-off rate by previously treating the bundle of fibers in contact with a liquid material with a higher boiling point than the temperature of a molten resin in a die. SOLUTION: A bundle of fibers A is caused to pass through a clearance between compression rollers 2 after passing through a liquid material 1, then is introduced into a die 3 and is brought into contact with a molten thermoplastic resin to be supplied from an extruder 4. Next, the bundle of fibers A is drawn out of the die 3, then is hauled off using a haul-off roll 6 after cooling a strand with a cooling water 5, and is cut to the desired length of a pellet by a pelletizer 7. In this case, the liquid material 1 to be used is of such a physical property that its boiling point is higher than the temperature of the molten resin in the die 3 and the material 1 does not affect the thermoplastic resin to be used adversely. Thus it is possible to enhance the impregnating properties of the resin with the bundle of fibers A and make it possible to use the resin of a molecular weight level to be used routinely, and further, increase the haul-off rate significantly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber reinforced composite material and a fiber reinforced composite material, and more particularly, to a fiber reinforced composite material capable of increasing the impregnation of a fiber bundle with a resin and greatly improving the take-up speed. A method for producing a composite material,
And a fiber-reinforced composite material and glass fiber-reinforced pellets having specific properties.

[0002]

2. Description of the Related Art Conventionally, fiber-reinforced composite materials in which a fiber bundle (a roving of collected filaments) is impregnated with a thermoplastic resin have been widely used as a material for various structures because they give molded articles having excellent mechanical properties. ing. As a method for producing such a fiber-reinforced composite material, for example, a fiber bundle is impregnated with a thermoplastic resin by a melt drawing (melt drawing) method, and in some cases, cut into pellets having a length of about 3 to 300 mm. Has proposed a method for producing a fiber-reinforced composite material (JP-B-63-37694).
No.). However, in this method, it is generally difficult to sufficiently impregnate the fiber bundle with the resin because the melt of the thermoplastic resin has a high viscosity. Therefore, various measures have been taken in order to improve this. Has been taken. For example, as disclosed in JP-B-63-37694, the molecular weight of the resin is reduced and the viscosity is remarkably reduced to promote the impregnation.
As seen in the specification of Japanese Patent No. 2, a method of devising a die, applying pressure so as to rub a fiber bundle, and promoting impregnation has been proposed and put to practical use.

[0003] Although the impregnation of the resin into the fiber bundle is greatly improved by these methods, it is not sufficiently satisfactory. There were problems such as the occurrence of serious troubles at the empty line at the molding site. Also,
These methods have drawbacks in that the pull-out resistance is large, the pull-out speed is only about several tens cm / min, and the productivity is low, as shown in the examples in JP-B-63-37694. If an attempt is made to increase the drawing speed, the impregnation property is unavoidably reduced, and the fibers are damaged, the fibers are cut, and the production stability is reduced. Therefore, in order to solve these problems, the present inventors first increase the productivity by passing the fiber bundle through the aqueous emulsion and improving the wettability between the fiber bundle and the molten resin.
In addition, a method for producing a fiber-reinforced composite material having good resin impregnation has been proposed (JP-A-8-90659). However, in this method, it is necessary to dry out the medium attached to the fiber bundle before the fiber bundle comes into contact with the molten resin in the die, and thus not only requires a considerably long drying oven but also a drying method. There is a problem that processing cost is required, and it is not always satisfactory. Japanese Patent No. 2586078 and Japanese Patent Application Laid-Open No. 58-138 disclose a technique for improving a pressing method when a fiber bundle is impregnated with a resin.
The inventions described in Japanese Patent Application Laid-Open Nos. 616, 6-254857, 6-254,976 and the like are known, but all of these have disadvantages such as insufficient impregnation and insufficient take-up speed. have.

[0004]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art, improves the impregnation of the resin into the fiber bundle, and significantly increases the take-up speed, thereby improving the productivity. Aqueous emulsion treatment,
It is an object of the present invention to provide a method for producing a fiber-reinforced composite material that does not require a step of drying a fiber bundle before introducing it into a die, such as a resin solution treatment.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, before the fiber bundle was brought into contact with the molten thermoplastic resin in the die, the fiber bundle was previously removed. It has been found that the object can be achieved by performing a contact treatment with a liquid having a boiling point higher than the temperature of the molten resin in the die. The present invention has been completed based on such findings. That is, according to the present invention, the fiber bundle is guided into a die, brought into contact with a molten thermoplastic resin, then pulled out of the die, and cooled to produce a fiber-reinforced composite material. An object of the present invention is to provide a method for producing a fiber-reinforced composite material, which comprises performing a contact treatment with a liquid having a higher boiling point. Also,
The present invention relates to a fiber in which the reinforcing fibers are arranged substantially in parallel, the content of the fiber is 15 to 80% by weight, the content of the thermoplastic resin component is 85 to 20% by weight, and the petroleum oil is contained. Also provided is a reinforced composite material, further comprising a reinforced polyolefin pellet containing 15 to 80% by weight of glass fiber having a length in the fiber direction of 3 to 100 mm, wherein the glass fiber is substantially the same length and parallel to the pellet. And glass fiber reinforced pellets containing 3% by weight or less of petroleum oil.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fiber bundle used in the method of the present invention is not particularly limited.
Made of carbon fiber, boron fiber, silicon carbide fiber, or metal fiber such as aluminum fiber, stainless steel fiber, copper fiber, brass fiber, nickel fiber, or organic fiber such as polyamide fiber, polyester fiber, polyarylate fiber, polyimide fiber, etc. Can be used. These fibers may be used singly or in combination of two or more. Glass fibers are particularly preferred. The diameter of the fiber is desirably in the range of 3 to 30 μm, preferably 6 to 25 μm from the viewpoints of handling properties and mechanical properties of the obtained composite material. In the present invention, the fiber may be treated in advance with a surface treatment agent in order to improve the wettability and adhesiveness with the resin. Examples of the surface treating agent include silane-based, titanate-based, aluminum-based, chromium-based, zirconium-based, and borane-based coupling agents. Among these, silane-based coupling agents and titanate-based coupling agents are exemplified. Preferred are silane coupling agents.

As the silane coupling agent, for example, triethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- (aminoethyl) -γ
-Aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxy Silane, γ-chloropropyltrimethoxysilane and the like. Among them, γ-aminopropyltriethoxysilane, N-β-
Aminosilanes such as (aminoethyl) -γ-aminopropyltrimethoxysilane are preferred. The method for treating the fiber with the surface treatment agent is not particularly limited, and any method conventionally used, for example, an aqueous solution method, an organic solvent method, a spray method, or the like can be used.

In the present invention, the fiber bundle has a fiber diameter of 3 to 30 μm from the viewpoints of resin impregnation, wettability and adhesion to the resin, mechanical properties of the obtained composite material, cost, and handleability. Those comprising 200 to 2000 glass fibers are preferred, and those which have been surface-treated with an aminosilane-based coupling agent are particularly preferred. In the method of the present invention, there is no particular limitation on the thermoplastic resin to be impregnated by guiding the fiber bundle into a die and making contact therewith, and any one is conventionally selected from those commonly used in fiber-reinforced composite materials. Can be used. Examples of the thermoplastic resin include homopolymers of α-olefins such as ethylene; propylene; butene-1; 3-methylbutene-1; 3-methylpentene-1; and 4-methylpentene-1, and copolymers thereof. Or polyolefin resins such as copolymers of these with other copolymerizable unsaturated monomers, or polystyrene resins, polyvinyl chloride resins, polyamide resins, polyester resins, polyacetal resins, polycarbonates Resin, polyaromatic ether or thioether resin, polyaromatic ester resin,
Examples include polysulfone-based resins, acrylate-based resins, and fluorine-based resins. These may be used alone or in combination of two or more. Among these, polyolefin resins are preferable. Examples of the polyolefin resins include high-density, medium-density, and low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate. Polyethylene resins such as copolymers, propylene homopolymers, propylene-ethylene block copolymers and random copolymers, polypropylene resins such as propylene-ethylene-diene compound copolymers, polybutene-1, poly-4-methyl Although pentene-1 and the like can be mentioned, in the present invention, among them, a polypropylene resin is particularly preferable.

The polypropylene resin is not particularly limited, and a wide range of molecular weights (melt index) can be used. However, from the viewpoint of long-term heat stability, the melt index (MI) (temperature 230 ° C., load 2. 16 kg) is preferably 60 g / 10 min or less, particularly 30 g / 1
Those having a duration of 0 minutes or less are preferred. Further, those containing an acid-modified polyolefin-based resin are preferable because the interface strength is improved, the tensile strength and the like are greatly improved, and the resin impregnation into the fiber bundle is promoted. Examples of the polyolefin resin used for the acid-modified polyolefin resin include polypropylene, polyethylene, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-non-conjugated diene compound copolymer (eg, EPDM), ethylene -Aromatic monovinyl compound-conjugated diene compound copolymer rubber. Examples of the α-olefin include propylene; butene-1; pentene-
1; hexene-1; 4-methylpentene-1 and the like, and these may be used alone or in combination of two or more. Among these polyolefin-based resins, polypropylene and polyethylene are preferred, and polypropylene is most preferred.

The unsaturated carboxylic acids used for the acid modification include unsaturated carboxylic acids and derivatives thereof. Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid. Acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid, angelic acid and the like; and derivatives thereof include acid anhydrides, esters, amides, imides, metal salts and the like. For example, maleic anhydride, itaconic anhydride Acid, citraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic monoethyl ester, acrylamide, maleic monoamide, maleimide, N-butylmaleimide, sodium acrylate, sodium methacrylate Can be mentioned. Among these, unsaturated dicarboxylic acids and derivatives thereof are preferred, and maleic anhydride is particularly preferred.
These unsaturated carboxylic acids and derivatives thereof may be used alone or in combination of two or more when modifying the polyolefin resin. The modification method is not particularly limited, and various conventionally known methods can be used. For example, a method of dissolving the polyolefin resin in an appropriate organic solvent, adding an unsaturated carboxylic acid or a derivative thereof and a radical generator, stirring and heating, or supplying the respective components to an extruder to carry out graft copolymerization. A method for performing the method can be used. In the modified polyolefin resin, the amount of the unsaturated carboxylic acid or derivative thereof added is 0.01 to 20% by weight, preferably 0.05 to 1% by weight.
Those in the range of 0% by weight are preferred, and maleic acid-added polypropylene is particularly preferred.

On the other hand, in the method of the present invention, the liquid used for the contact treatment of the fiber bundle has a boiling point higher than the temperature of the molten resin in the die and adversely affects the thermoplastic resin used. Is not particularly limited, and various types can be used. Such liquids are preferably liquid at room temperature, such as liquid paraffin, process oil, petroleum oils such as high-boiling aromatic oils, liquid resin additives such as various plasticizers, liquid polybutene, etc. Liquid resins such as α-olefin oligomers and liquid polybutadiene, as well as high-boiling solvents and heating media. After these liquids are processed, a part of them remains and enters the die. Therefore, it is preferable to use those liquid materials which do not adversely affect the physical properties even when mixed into the molten resin impregnated in the die and are compatible. Of these, petroleum oils such as liquid paraffin are preferred. These liquid materials may be used alone or in combination of two or more. As described above, the liquid material needs to have a boiling point higher than the temperature of the molten resin in the die, and when the boiling point is equal to or lower than the temperature of the molten resin in the die, the fiber bundle contact-treated with the liquid material is used. In addition, when the molten material is brought into contact with the molten thermoplastic resin in the die, evaporation of the liquid material occurs, and the impregnation of the fiber bundle with the resin is reduced.

In the method of the present invention, the fiber bundle is guided into a die, and before being brought into contact with the molten thermoplastic resin, the fiber bundle is subjected to a contact treatment with the liquid material in advance, so that the fiber bundle is wetted. It is believed that the air is expelled, thereby improving the impregnation of the thermoplastic resin. Specifically, after passing the fiber bundle through the liquid material, or after applying the liquid material to the fiber bundle with a roll coater, if desired,
A method of passing the fiber bundle through a compression roll or a tension bar to promote the impregnation of the fiber bundle with the liquid material and expelling air in the fiber bundle is preferably used. Unnecessary liquids can be removed and the amount can be kept constant by the treatment with the compression rolls or the like. By this operation, the impregnating property of the resin in the die is remarkably improved, and impregnation with a high molecular weight resin is possible. When a roll coater is used, the rotation speed is adjusted in accordance with the take-up speed of the fiber bundle, thereby adjusting the amount of the liquid material that is scraped up and wetted by the fiber bundle.

Next, the fiber bundle treated as described above is guided into a die, and the temperature supplied to the extruder is 200 to 3.
After being brought into contact with a molten thermoplastic resin at about 00 ° C., it is pulled out from the die. The strands drawn from the dies are cooled and then taken out by a take-up machine.
It is preferable to cut into a length of about 100 mm and pelletize. If the length of the pellet is less than 3 mm, the reinforcing effect may not be sufficiently exerted. If the length is more than 100 mm, biting during molding may be poor, and stable production may be difficult. Further, the fiber bundles drawn out from the dies can be made into a plate shape or an irregular shape by being aligned. The content ratio of the fiber and the resin component in the fiber-reinforced composite material thus obtained is such that the fiber is 15 to 80% by weight,
Preferably, the resin component is in the range of 85 to 20% by weight. When the content of the fiber is less than 15% by weight, the amount of the fiber is insufficient, and it may be difficult to quantitatively extract the fiber.
If the content is more than 10% by weight, it may be difficult to impregnate the resin.
From the viewpoint of resin impregnating and drawing properties, fibers are particularly
Preferably, it is 70% by weight and the resin component is in the range of 75 to 30% by weight. Thus, the reinforcing fibers are arranged substantially in parallel, the fiber content is 15 to 80% by weight, the thermoplastic resin component content is 85 to 20% by weight, and a small amount of petroleum oil is contained. The resulting fiber reinforced composite material is obtained. More specifically, for example, a strand-like fiber-reinforced composite material is cut as described above, and a glass fiber having a length in the fiber direction of 3 to 100 mm is 15 to 80% by weight.
The reinforced polyolefin pellets to be contained. The pellets are glass fiber reinforced pellets in which the glass fibers are arranged in parallel with the pellets at substantially the same length, and contain 3% by weight or less, preferably 2% by weight or less of petroleum-based oil.

In the present invention, if necessary, the thermoplastic resin may contain other resins, fillers and additives for improving various physical properties. For example, as impact modifiers, ethylene-propylene copolymer rubber,
Rubbers such as polybutadiene rubber, styrene-butadiene-styrene block copolymer rubber (SBS), and hydrogenated SBS-styrene-ethylene-butylene-styrene block copolymer rubber (SEBS) can also be added. In consideration of the required characteristics of molded products, metal powder, carbon black, graphite, talc, mica, clay, calcium carbonate, silica, aluminum hydroxide, magnesium hydroxide, calcium sulfate, glass fiber, calcium titanate whisker , Inorganic fillers such as fibrous magnesium oxysulfate, organic fillers such as cross-linked resin powder, crystallization accelerators, antioxidants (phosphorous, phenolic, sulfuric, etc.), neutralizing agents, foaming agents, lubricants , Dispersants, peroxides, heat stabilizers, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, flame retardant aids, plasticizers, epoxy compounds, metal deactivators, zinc sulfide, titanium oxide, etc. And other additives such as pigments and dyes. The fiber-reinforced composite material obtained in this manner may be molded as it is, or may be molded by blending with a resin not containing the same or similar fiber, or with another resin. next,
FIG. 1 is a schematic diagram for explaining an example of the method of the present invention. First, after passing the fiber bundle A through the liquid material 1,
It passes between the compression rolls 2, is further guided into a die 3, and is brought into contact with a molten thermoplastic resin supplied from an extruder 4.
Next, the strand is drawn out from the die 3, the strand is cooled by the cooling water 5, taken up by a take-up roll 6, and further cut into pellets of a desired length by a pelletizer 7.

[0015]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 A fiber bundle (glass roving) made of glass fiber having a diameter of 10 μm was drawn out, passed through a tank containing liquid paraffin (boiling point: 358 ° C., manufactured by Idemitsu Kosan Co., Ltd., trade name: Daphne Oil CP50S), The fiber bundle was impregnated with the liquid paraffin by passing between the compression rolls, and was further guided into a die. In a die, MI is 10g / 10
(250 ° C), melt (250 ° C) of acid-modified polypropylene (maleic anhydride added 0.05% by weight) for 2 minutes (temperature: 230 ° C, load: 2.16 kg). A composite material was manufactured. Pickup speed is 1
６０60 m / min. The obtained fiber-reinforced composite material had a diameter of 3 mm composed of 60% by weight of glass fiber and 40% by weight of resin. This fiber-reinforced composite material was further cut into a length of 12 mm to obtain a pellet. The pellets obtained at a drawing speed of 30 m / min contained 0.6% by weight of liquid paraffin. Next, 25 kg of the pellets were put into a 100-liter tumbler,
After blending for a minute, it was taken out and examined for the state of fiber detachment. Further, after 50% by weight of the obtained pellets and 50% by weight of polypropylene (MI = 20 g / 10 minutes) are dry-blended, 140 × 140 × 2 m by injection molding.
m was prepared, and the state of defibration of the fibers was visually observed. Table 1 shows the results.

Comparative Example 1 Example 1 was repeated except that the fiber bundle was directly introduced into the die without passing through the liquid paraffin storage tank.
It carried out similarly to. The results are shown in Table 1. Comparative Example 2 In Comparative Example 1, instead of the acid-modified polypropylene (maleic anhydride addition amount: 0.05% by weight) as the molten resin to be impregnated in the die, MI = 3.
The operation was performed in the same manner as in Comparative Example 1 except that polypropylene of 00 g / 10 minutes was used. The results are shown in Table 1. Comparative Example 3 The procedure of Example 1 was repeated, except that a maleic acid-modified polypropylene-based aqueous emulsion was used instead of liquid paraffin. The results are shown in Table 1.

Example 2 A fiber bundle made of polyarylate fiber having a diameter of 8 μm was drawn out, passed through a tank containing polybutene (molecular weight: 350), and then passed between compression rolls to impregnate the fiber bundle with polybutene. This was further led into a die. In a die, a melt of acid-modified polypropylene (maleic anhydride addition 0.05% by weight) having an MI of 30 g / 10 min (23
(0 ° C.), and then taken out and cooled to produce a fiber-reinforced composite material. The take-up speed was 10 m / min. The obtained fiber-reinforced composite material had a diameter of 3 mm, comprising 40% by weight of polyarylate fibers and 60% by weight of resin. This fiber reinforced composite material is further extended by 15 m
m to obtain pellets. Next, this pellet 25
kg was put into a 100-liter tumbler, blended for 15 minutes, taken out, and the state of fiber detachment was examined. Furthermore, using the obtained pellets, 1
A flat plate of 40 × 140 × 2 mm was prepared, and the state of fibrillation of the fiber was visually observed. The results are shown in Table 1.

Example 3 A fiber bundle made of carbon fibers having a diameter of 12 μm was drawn out, liquid paraffin was attached to and impregnated with a roll coater, and then passed between compression rolls to impregnate the liquid bundle with the liquid paraffin. , And led it into the dice.
In a die, MI was 5 g / 10 min (temperature: 200 ° C., load: 5
kg) of a polystyrene melt (250 ° C.), which was then withdrawn and cooled to produce a fiber-reinforced composite material. The take-off speed was 20 m / min. The obtained fiber-reinforced composite material had a diameter of 2.5 mm consisting of 50% by weight of carbon fiber and 50% by weight of resin. This fiber-reinforced composite material was further cut into a length of 10 mm to obtain a pellet. Next, 25 kg of these pellets were put into a tumbler of 100 liters, blended for 15 minutes, and then taken out.
The state of fiber detachment was examined. Further, a flat plate of 140 × 140 × 2 mm was prepared by injection molding using the obtained pellets, and the state of defibration of the fibers was visually observed. The results are shown in Table 1.

[0019]

[Table 1]

[Note] GF: Glass fiber defibration status ：: Unfibrillated fiber is not recognized △: Some unfibrillated fiber is recognized (less than 5) ×: Unfibrillated fiber is Many (more than 5)

[0021]

According to the present invention, the impregnating property of the resin into the fiber bundle can be increased, the resin having a molecular weight level commonly used can be used, and the take-up speed can be greatly improved. Unlike the emulsion treatment, a step of drying the fiber bundle before introducing it into the die is not required, and the fiber-reinforced composite material can be manufactured with extremely high productivity. The fiber-reinforced composite material obtained by the method of the present invention is suitable for various automobile parts such as instrument panel cores, bumper beams, door steps, roof racks, rear quarter panels, air cleaner cases, and other concrete panels and cable troughs. Used for

[Brief description of the drawings]

FIG. 1 is a schematic process diagram illustrating an example of the method of the present invention.

[Explanation of symbols]

 1: liquid material 2: compression roll 3: die 4: extruder 5: cooling water 6: take-up roll 7: pelletizer A: fiber bundle

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08K 5/01 C08L 23/12 7/14 23/26 C08L 23/12 B29C 67/14 L 23/26 DB29K 105: 12 309 : 08

Claims (7)

[Claims] 1. A fiber bundle is guided into a die, brought into contact with a molten thermoplastic resin, drawn out of the die, and cooled to produce a fiber-reinforced composite material. A method for producing a fiber-reinforced composite material, comprising contacting with a liquid having a higher boiling point. 2. The method according to claim 1, wherein the molten thermoplastic resin is a polypropylene resin which may contain an acid-modified polyolefin resin. 3. The liquid material is a petroleum oil.
The manufacturing method as described. 4. The method according to claim 1, wherein the contact treatment of the fiber bundle with the liquid material is performed by passing the fiber bundle through the liquid material or by applying the liquid material to the fiber bundle with a roll coater. 5. The fiber-reinforced composite material has a length of 3 to 100 m.
The production method according to claim 1, wherein the pellets are cut into m. 6. The reinforcing fibers are arranged substantially in parallel, have a fiber content of 15 to 80% by weight, a thermoplastic resin component content of 85 to 20% by weight, and contain a petroleum oil. Fiber reinforced composite material. 7. Reinforced polyolefin pellets containing 15 to 80% by weight of glass fibers having a length in the fiber direction of 3 to 100 mm, wherein the glass fibers are arranged in parallel with substantially the same length as the pellets. , Three petroleum oils
Glass fiber reinforced pellets containing up to 10% by weight.