JPH09136976A - Tow prepreg and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tow prepreg that can give excellent toughness to a product obtained therefrom without damaging handleability, thermal properties, and mechanical properties and a method for the production thereof. SOLUTION: This tow prepreg comprises (A) five or less reinforcing fiber tows having a tensional modulus of 200 GPa or more, (B) a fibrous thermoplastic resin having a tensional modulus of 100 GPa or less, and (C) a thermosetting resin having a viscosity of 3,000 to 100,000 poises at 50 deg.C. A tow prepreg with the component (B) localized on its outer surface is prepared and a certain amount of a resin is fed to at least one surface of a flattened tow. Upon or immediately after the contact of the resin with the tow, the resin is allowed to penetrate in the direction of the thickness of the tow, so that the resin is infiltrated into the tow by lateral movement of the filament constituting the tow. Immediately before or upon the cooling, a fibrous thermoplastic resin having a tensional modulus of 100 GPa or less is arranged on its surface and then it is taken up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tow prepreg capable of imparting excellent toughness to a fiber reinforced composite material and a method for producing the tow prepreg.

[0002]

2. Description of the Related Art Intermediate materials used for fiber-reinforced composite materials are generally called prepregs. Reinforcement fiber tows are lined up on a hot-melt film, which is thinly coated with resin on release paper, and topped from above. Do you cover the film,
Alternatively, it is a general production method that a hot melt film is further stacked from above, and then the constituent filaments of the reinforcing fiber tow are impregnated with a resin by heating and / or pressurizing, and then wound up to be manufactured. As a typical example, a method of sandwiching a hot melt film from above and below to impregnate a resin is disclosed in JP-A-3-149230 and JP-B-4-505.
No. 7 discloses this.

Since the method disclosed in the above publication handles a large number of reinforcing fiber tows and is wide and sandwiched by a protective film such as release paper, it has an advantage that it can be stably manufactured without stains in the manufacturing process. . A method for producing a tow prepreg in which one tow is impregnated with a hot melt resin is disclosed in Japanese Examined Patent Publication No. 5-80330, and this method removes release paper or a hot melt film to produce a prepreg in a tow unit. Is the way to do it.

[0004]

However, the prepreg manufactured by the method disclosed in Japanese Patent Laid-Open No. 3-149230 and Japanese Patent Publication No. 4-5057 has a resin content of a wide range in the width direction. Very little variation,
The variation of the resin content is large when viewed with a narrow width of about one tow, and when the prepreg manufactured with a wide width is cut and used with a narrow width, the variation of the resin content between the prepregs becomes too large. Since it is not possible to strictly control the width of a large number of tows, even if the amount of resin per unit area of the hot melt film is constant, there is a change in the amount of fibers per unit volume due to the change in the spread of the tow. The resin content (% by weight) per unit area after resin impregnation fluctuates, and when the prepreg is used in a wide width, the fluctuation is canceled out and the accuracy is improved, but for example 1 to 5 wide prepregs are used. This is because when the slit tape is cut with a width corresponding to a certain degree of spread, or about 1 to 5 tows are torn off from a wide prepreg to obtain a tow prepreg, the resin content varies greatly.

Further, regarding the resin impregnation speed, since the tows are placed side by side and pressed from above and below by a protective sheet such as release paper, it is almost impossible to move the filaments forming the tow, and the impregnation speed of the resin is Heating from above and below via release paper, pressure conditions and thermosetting resin are determined in consideration of the life of the resin, and it is not necessary to simply lower the viscosity by heating, but the length of the impregnating process Due to such problems, there was a limit to the improvement of production speed. Further, when sandwiched by a hot melt film from above and below, air is left in the tow, so that impregnation failure is likely to occur.

Further, in the method for producing a tow prepreg described in Japanese Patent Publication No. 5-80330, a resin is coated in a state where the tow width is widened to form a film on the opposite surface of the tow, and the tow is impregnated by kneading. However, the impregnation in this method is focused on forming a resin film on the surface of the flat tow and then pushing the resin uniformly into the tow. However, the problem with this method is that a uniform film is first obtained. That is, in this method, the coating amount is controlled by the gap between the doctor blade and the tow, but the bulk of the tow and the tow thickness in the width direction are not uniform, and since they fluctuate in the longitudinal direction, the coating thickness is constant even if the clearance is constant. It is extremely difficult to accurately control the. Further, even when the tow is kneaded by the kneading rolls, the resin tends to move in the thickness direction, but since the resin does not move laterally, the uniformity depends on the coating property of the resin.

On the other hand, thermosetting resins typified by epoxy resins have various characteristics such as excellent heat resistance, solvent resistance, and mechanical characteristics in addition to the above characteristics, but have poor toughness, and therefore impact resistance. It has the drawback of being inferior in sex. In particular, when a fiber-reinforced resin composite material is used as a laminate, the resistance to impact is often governed by the delamination strength, so that a fiber-reinforced resin composite material using a thermosetting resin with low toughness as a matrix is used. The result is that the impact resistance is also low, and therefore, the use of the fiber-reinforced resin composite material, particularly the use as a structural material, has been considerably limited.

As a method for improving the defects of the thermosetting matrix resin, a method of adding a rubber component or a thermoplastic resin is known, but it is necessary to add a large amount in order to obtain a sufficient toughness improving effect. Therefore, the heat resistance, solvent resistance, etc. are significantly reduced.

Further, a method of adding a thermoplastic resin, especially so-called engineering plastic having excellent heat resistance and solvent resistance, is disclosed in JP-A-61-212543 and JP-A-6-212543.
It has been proposed in JP-A 1-228016, JP-A-58-134111, etc., and it has been reported that a decrease in heat resistance, solvent resistance and the like can be suppressed as compared with the addition of a rubber component, but in order to obtain sufficient toughness. Requires a large amount of addition, and problems such as a decrease in processability during prepreg production or a decrease in tack level of the prepreg due to an increase in the viscosity of the entire system still remain largely in this method.

Attempts to improve the toughness of these thermosetting matrix resins themselves are not very effective methods from the viewpoint of improving the delamination strength of the laminate. A method of intensively distributing fine particles of a thermoplastic resin between layers for the purpose of effectively improving the delamination strength of a laminate is proposed in Japanese Patent Laid-Open No. 110537/1989, but the tack level of the prepreg is greatly increased. In addition to inevitable deterioration, new problems such as complicated processes and complicated quality control will occur. Attempts to localize chopped fibers, milled fibers, etc. between layers for the same purpose have also been proposed, but similar problems are unavoidable,
The effect is not always sufficient.

Further, a method of inserting a kind of impact absorbing layer called interleaf between layers is also disclosed in USP347273.
0, JP-A-51-58484, JP-A-60-63
No. 229, JP-A No. 60-231738, etc., but they are widely put into practical use because the layers become thicker and the fiber ratio decreases, and the heat resistance and handleability decrease. Has not reached.

[0012]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and does not impair the excellent handling properties, thermal properties, and mechanical properties inherently possessed by a prepreg having a thermosetting resin as a matrix. It is possible to produce the above-mentioned tow prepreg with high productivity by precisely controlling the resin content using a tow prepreg and a hot-melt resin capable of imparting excellent toughness to the obtained molded product, and performing efficient uniform impregnation. It provides a method.

[0013]

The first gist of the present invention is (A) 5 or less reinforcing fiber tows having a tensile modulus of 200 GPa or more, (B) a fibrous thermoplastic resin having a tensile modulus of 100 GPa or less, ( C) Viscosity at 50 ° C. is 3000 to 1
It is a tow prepreg characterized by being made of a thermosetting resin of 00000 poise, and (B) is localized on its outer surface. The second gist is to quantitatively supply the resin to at least one side of the flattened tow. At the same time as or immediately after contacting the resin with the tow, the resin is allowed to penetrate in the thickness direction of the tow, the filaments forming the tow are laterally moved to uniformly impregnate the resin with the tow, and immediately before or simultaneously with cooling. A method for producing a tow prepreg, which comprises arranging a fibrous thermoplastic resin having a tensile elastic modulus of 100 GPa or less on the surface thereof and winding the resin.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Elastic modulus 2 of (A) in the present invention
As the reinforcing fiber of 00 GPa or more, the reinforcing fiber used in ordinary fiber-reinforced composite materials such as carbon fiber, graphite fiber, boron fiber, etc. is used as it is, but the tensile strength is 3500.
Carbon fiber or graphite fiber having a pressure of MPa or more is preferably used.
Of these, carbon fibers and graphite fibers having a high strength and a high tensile strength of 4500 MPa or more and an elongation of 1.7% or more are most preferably used.

The elastic modulus (B) of the present invention is 100 GP.
The fibrous thermoplastic resin having a or less is the most important constituent element in the present invention. This is because the use of a fibrous shaped thermoplastic resin for the first time makes it possible to impart excellent toughness to a molded product without impairing the excellent handling properties, thermal properties, and mechanical properties inherent in the base prepreg. This is because the object of the present invention to provide a prepreg for a composite material can be achieved.

That is, since the thermoplastic resin can be effectively arranged on the surface layer of the prepreg by shaping it into a fibrous shape, sufficient toughness improvement can be achieved with a small amount of the thermoplastic resin, and further, the prepreg can be achieved. Since it is easy to control the tack level, the problem of lowering the tack level, which has been a problem in the prior art, does not occur. Further, as compared with the prior art such as a system in which fine particles are added, the distribution of the thermoplastic resin component can be easily controlled, and accordingly, there is an advantage that the quality control is easy.

The elastic modulus (B) of the present invention is 100 GP.
Examples of the fibrous thermoplastic resin of a or less include polyethylene, polypropylene, polyamide, polyester, polyacetal, polycarbonate, polyarylate, polysulfone, polyetheretherketone, polyetherimide, polyimide, polyamideimide, polyphenylene oxide, polyphenylene sulfide, and polybenz. Fibers formed by so-called engineering plastics such as imidazole and polyarylsulfone, and super engineering plastics are preferably used, but not limited thereto. However, some liquid crystal polymers such as polyparaphenylene benzbisthiazole are formed into a fibrous shape, ultra high modulus polyethylene fibers manufactured by a special method, and some aramid fibers represented by Kevlar 49. Has an elastic modulus of 10
Since it is 0 GPa or more and the toughness improving effect is poor, it is not used.

The elastic modulus of (B) in the present invention is 100 G.
As the fibrous thermoplastic resin having Pa or less, one having a reactive group capable of reacting with the thermosetting matrix resin (C) in the molecular chain is particularly preferable. Therefore, when the thermosetting matrix resin (C) is an epoxy resin, the fibrous thermoplastic resin (B) has a functional group capable of reacting with the epoxy resin such as an amino group, an amide group and a phenolic hydroxyl group. Those having are particularly preferable.

The form of the fibrous thermoplastic resin is preferably a monofilament or a bundle thereof, but is not necessarily limited thereto. The fiber diameter is preferably 100 μm or less, and particularly preferably 50 μm or less. When used as a multifilament, the total denier is preferably 1,000 denier or less.
Particularly preferably, it is not more than 00 denier.

It is also possible to use a combination of two or more kinds of fibrous thermoplastic resins having different materials and denier. There is no particular limitation on the combination method, and 2
A method of aligning seed fibers or a method of using as a mixed yarn by interlacing may be appropriately adopted. Furthermore, 2
A composite yarn having a core / sheath structure, a sea-island structure or the like obtained by simultaneously spinning at least one kind of thermoplastic resin can also be used. Composite yarn made of two or more types of fibers with different properties,
Using as a mixed yarn is one of the effective methods for balancing various characteristics. A so-called spun yarn obtained by spinning short fibers can also be exemplified as one preferable form of the fibrous thermoplastic resin (B).

The ratio of the fibrous thermoplastic resin (B) is 40 parts by weight or less, preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the thermosetting matrix resin (C). If it is less than 0.5 parts by weight, a sufficient effect of improving the toughness cannot be obtained. On the contrary, if it exceeds 40 parts by weight, not only the effect of improving the toughness reaches its ceiling but also the tack level of the prepreg is lowered, which is not preferable.

It is important that the fibrous thermoplastic resin (B) in the present invention is localized near the outer surface of the prepreg. When it is completely buried in the center of the prepreg, sufficient toughness improving effect cannot be obtained. However, it is not preferable that the fibrous thermoplastic resin is completely raised from the surface of the prepreg, and most of the fibrous thermoplastic resin is preferably embedded in the thermosetting matrix resin. Further, it is more preferable that the fibrous thermoplastic resin is aligned in one direction at equal intervals, but it is not necessarily limited thereto. Of course, align in two or more directions,
It is possible to dispose them crossing each other, and a high effect can be obtained, but the process becomes complicated. The alignment direction is not particularly limited and may be present at any angle to the reinforcing fiber, but aligning in the same direction as the reinforcing fiber is the easiest in the process.

The thermosetting resin (C) used in the present invention has a viscosity of 3000 to 10000 at 50 ° C.
Any resin can be used as long as it is a resin that is cured with a thermosetting resin of 0 poise to at least partially form a three-dimensional cured product. When the above viscosity is less than 3000 poise, the unwinding property is insufficient when the tow prepreg is used.
If it exceeds 00 poise, the impregnation of the resin into the reinforcing fiber or the like becomes insufficient, which is not preferable. Representative examples include an epoxy resin, a maleimide resin, a polyimide resin, a resin having a cyanate ester terminal, a resin having an acetylene terminal, a resin having a vinyl terminal, a resin having an allyl terminal, and a resin having a nadic acid terminal. Among them, those having the above viscosity within the above range or those having the above viscosity range by being diluted are used.

An epoxy resin is used as the most suitable thermosetting resin of the present invention. In particular, epoxy resins containing amines and phenols as precursors are preferable. Specifically, tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-
Examples include m-aminophenol, various isomers of triglycidylaminocresol, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and the like.
It is not limited to this. Also, a brominated epoxy resin obtained by bromizing these epoxy resins is used. These epoxy resins may be used alone, but may be used as a mixture of two or more kinds depending on the purpose.

The epoxy resin is usually used in combination with a curing agent, but the curing agent used in the present invention is not particularly limited and has a functional group capable of reacting with the epoxy resin such as an amino group and an acid anhydride group. Can be appropriately used, but aromatic amino compounds represented by various isomers of diaminodiphenyl sulfone, dicyandiamide, and aminobenzoic acid esters are suitable.

As the thermosetting matrix resin (C) in the present invention, it is also possible to use the above thermosetting resin to which a thermoplastic resin or an oligomer thereof is added.
Especially polyimide, polyetherimide, polysulfone,
So-called engineering plastics such as polyether sulfone and polyether ether ketone are preferable from the viewpoint of heat resistance, and those having a functional group capable of reacting with a thermosetting resin at the molecular end or in the molecular chain are more preferable.

The amount of the thermoplastic resin component added to the thermosetting resin component is preferably 30% by weight or less, more preferably 15% by weight or less. If the addition amount of the thermoplastic resin component is 30% by weight or more, the viscosity of the system becomes too high, which not only causes impregnation failure at the time of prepreg-forming, but also causes drastic deterioration of drape characteristics.

Inorganic fine particles such as finely powdered silica and an elastomer component such as a butadiene / acrylonitrile copolymer are added to the thermosetting resin in a small amount within a range that does not sacrifice prepreg characteristics, processing characteristics, mechanical characteristics, thermal characteristics and the like. It is also possible to do so.

The ratio of the reinforcing fiber (A) having a modulus of elasticity of 200 GPa or more to the thermosetting matrix resin (C) can be appropriately set according to the purpose, but the weight ratio is (A) / The range of (C) = 40/60 to 85/15 is suitable. A more preferable range is (A) / (C) = 60 /
It is 40-75 / 25.

Next, a method of manufacturing the tow prepreg of the present invention will be described. The embodiments of the present invention are as follows. That is, (1) The tow is heated in advance before the resin is quantitatively supplied to at least one surface of the flattened tow. (2) The toe width is expanded in advance so that it is restricted when contacting with the resin, and the toe width is narrowed when contacting with the resin. (3) The amount of resin deposited on the tow is controlled by the discharge amount of the resin discharge machine. (4) Simultaneously with or immediately after contacting the resin with the tow, the resin-adhered surface of the tow is rubbed to allow the resin to permeate in the thickness direction of the tow. (5) The lateral movement of the filaments forming the tow is performed by at least one means such as folding the tow, expanding the tow width, reducing the tow width, or twisting the tow. (6) In the resin uniform impregnation step by lateral movement of the filaments forming the tow, the tow is brought into contact with the rotating body rotating at a peripheral speed lower than the traveling speed of the tow. (7) In the cooling step, the tow width is narrowed and compressed at the same time on the cooling roll to control the cross-sectional shape of the tow. (8) Immediately before winding, the toe width is narrowed and simultaneously compressed to control the cross-sectional shape. (9) After uniformly impregnating the resin, the powder is attached to the tow. (10) After uniformly impregnating the resin, a separator carrier is supported on one surface of the tow. (11) Using a plurality of flattened tows, after contacting, permeating, uniformly impregnating and cooling the resin, each tow is individually wound.

The properties required for these resins are not particularly limited other than the above-mentioned viscosity.

It is desirable that the tow is flat in order to widen the contact area with the resin. Further, it is important to keep the tow width constant so that the contact area with the resin supplied in a fixed amount is constant. Generally, the reinforcing fiber tow does not have a constant width, so it is necessary to widen it. Examples of the method of widening include a method of rubbing with a cylindrical bar, a method of applying vibration, and a method of crushing.

In the present invention, the tow may be widened in-line or off-line more than the tow width at which the resin contacts the tow. Commercially available tape-shaped tows are considered offline tow widened tows. The width of the tow being widened is usually not stable and there are variations in how it spreads. Therefore, in order to stabilize the contact area with the resin at the time of resin contact, it is effective to narrow and stabilize the toe width immediately before or at the time of resin contact. As an example of the method, it is preferable to provide a groove having a predetermined width at the resin discharge port portion or a position immediately before the resin discharge port portion, and allow the tow to travel in the groove to narrow the tow width.

The preheating of the tow has the meaning of raising the tow temperature in advance so that the resin temperature does not drop when the resin permeates into the tow after contact with the resin. By preheating the tow temperature to be equal to or higher than the resin temperature before the contact, the tow temperature after the contact between the tow and the resin does not become lower than the resin temperature before the contact. As the preheating method, any of contact heating with a heating body and non-contact heating methods such as electric heating, dielectric heating, infrared heating, and atmosphere heating can be used.

As a method for quantitatively supplying the resin to the tow, it is preferable to use a molten resin discharger such as a plunger type discharger, a gear pump type discharger, and an extruder, and in particular, an ultraprecision gear pump or an extruder is used. Ideal for quantitative supply accuracy. In the case of a thermosetting resin, when the resin life after resin mixing becomes a problem, it is more ideal to supply the curing agent and the main agent while extruding them separately and mixing them with a static mixer. What is necessary at the time of adhesion is that the resin has a low viscosity and is easily attached to the tow. Although there is a method in which the resin is excessively applied and the resin is squeezed out by a die or the like to control the amount of the resin supplied, if the line speed becomes fast, yarn breakage easily occurs due to friction between the die and the toe, which is a problem at a high production speed.

As described in Japanese Patent Publication No. 5-80330, there is a method of controlling the clearance by a doctor blade or the like. Since it does not penetrate, the amount of adhesion can be controlled by the coating thickness, but it is difficult to control precisely because there is penetration in the tow, and if the tow is passed through the clearance, it is likely to cause thread breakage or clogging.

The content of the resin with which the tow is impregnated is preferably 10% by weight or more and 80% by weight or less. If it is less than 10% by weight, it is difficult to uniformly impregnate it, and if it exceeds 80% by weight, a problem occurs in the mechanical properties of the composite material molded product. In order to effectively exhibit the performance of mechanical properties, 30% by weight or more and 50% by weight or less is ideal.

In the present invention, it is important to allow the resin to permeate in the thickness direction of the tow at the same time as or immediately after the resin is contacted with the tow, in the sense of permeating and adhering the metered amount of the resin into the tow without delay. is there. In this respect, the method is remarkably different from the method of Japanese Patent Publication No. 5-80330 in which a resin film is simply formed on both sides of the tow. As a concrete method of infiltrating the resin, it is a good method to quickly scrape the toe surface side with which the resin is brought into contact. Here, “rubbing” means rubbing the tow on the rubbing body such as an arc or an edge.

At the time of rubbing, the tow is pressed against the side of the rubbing body, so that the resin pressure force inevitably acts in the tow thickness direction, and as a result, the resin permeates into the tow. Since the tow is pressed against the scraper, there is no gap between the scraper and the tow. The contact angle with the abrader is preferably 1 ° or more and 90 ° or less. If it is less than 1 °, the effect of resin penetration is small, and if it exceeds 90 °, the tension due to the resistance due to rubbing becomes too large and thread breakage may occur. If a sudden pressure is generated by rubbing, the penetration of resin into the tow will be uneven, but this is not intended to impregnate it uniformly, but to ensure the adhesion of the resin. The main focus is on.
Therefore, the homogenization of the resin impregnation becomes an important issue in the next impregnation step.

The lateral movement of the filaments in the resin impregnation step of the present invention is performed by applying an external force to the tows to move the filaments constituting the tows in the lateral direction (direction orthogonal to the longitudinal direction) to change the relative position between the filaments. By increasing the chances of contact between the resin and the filaments, the uniform impregnation effect can be improved over the impregnation effect due to simple pressurization or capillary phenomenon.

Specifically, it is carried out by at least one means such as folding the tow, expanding the tow width, reducing the tow width, or twisting the tow. The twisting means also adds the action of pushing the resin out of the tow.

In these means, the folding means and the twisting means tend to narrow the tow width like the width reducing means. When the means for narrowing the tow width and the means for widening the tow width are used together, the effect of uniform impregnation is enhanced. The twisting may be performed at the time of impregnation with the resin, and if a twist-free state is required after the impregnation, the twisting may be performed after the impregnation. In the case of false twist, it is not necessary to untwist, which is desirable when a tow without twist is required. If rubbing is applied at the same time as or immediately after twisting, the tow width tends to widen, and the uniformity of impregnation increases due to the movement of the resin in the thickness direction.

In the uniform impregnation of the lateral movement of the filaments, it is useful for rubbing the tow to bring it into contact with a rotating body that rotates at a peripheral speed lower than the running speed of the tow, for fuzz accumulation and roll cleaning. If it is rubbed, the tow will not be entangled with the surface of the rotating body, and since the rotating body is rubbed and rotated by the toe, the surface that comes into contact with the toe is always cleaned, improving the manufacturing environment. Is also useful. The peripheral speed of the rotating body may be lower than the traveling speed of the tow, and may be rotation in the direction opposite to the traveling direction of the tow.

The tow impregnated with the resin uniformly has a low resin viscosity due to heating and cannot be taken up immediately. Therefore, it is necessary to cool the tow to improve the operability. Immediately before or at the same time as cooling, it is necessary to dispose the above fibrous thermoplastic resin on the surface of the tow uniformly impregnated with the resin so that when the tow prepreg is formed, the fiber passion or the resin composition does not separate from the tow prepreg.

The cooling temperature may be a temperature at which the resin is peeled off without adhering to the surface of the cooling body, for example, the cooling roll, and it is necessary to determine the cooling temperature according to the resin system. For example, since a resin system used for a normal prepreg has a little stickiness at room temperature, it is preferable to lower the tow temperature within a range of 0 ° C to 30 ° C.

In the present invention, the tow impregnated with the resin can be narrowed and compressed at the same time by a grooved roll or a roll provided with a clearance to control the sectional shape.
The control position is preferably at the time of cooling after uniform impregnation or immediately before winding on a bobbin. If the tow is too cold immediately before being wound onto the bobbin and it is difficult to shape the cross-sectional shape, the cross-sectional shape may be regulated after heating to a temperature at which molding can be performed. In addition, the cross-sectional shape control can be performed off-line after winding the bobbin, and then re-rolling.

When pulling out the tow from the bobbin, the unwinding property of the tow becomes important. When a resin having a high viscosity at room temperature is used, adhesion between the tows is unlikely to occur and unwinding is not a problem, but if the viscosity is low, unwinding becomes impossible. As a method of solving this, there is a method of attaching powder to the surface to eliminate the tackiness of the surface. As the type of powder, various organic and inorganic powders can be used. As the organic substance, for example, a thermosetting resin or a thermoplastic resin can be used. Specifically, the thermosetting resin is preferably an epoxy resin or a phenol resin, and the resin may be hardened or uncured. As the thermoplastic resin, nylon, polypropylene, polyethylene or the like can be used. For inorganic substances, general fillers such as talc and silica can be used.

There are various methods for adhering the powder, but generally, a method of passing the tow in the fluidized bed or a method of spraying is preferable. The powder may be attached to the tow at any position after the resin is uniformly impregnated. As long as the tow has no tackiness and the unwinding property from the bobbin becomes good, the kind of powder, the particle size, and the adhered amount are not limited.

As a method for improving the unwinding property of the tow from the bobbin, a method of supporting a separator carrier on one surface of the tow is also suitably used. Various carriers can be used, but an inexpensive film-like one is preferable because it has good releasability from the tow and reduces the material cost. A polyethylene film and a polypropylene film are suitable as typical examples. Release paper may be used, but it is expensive. The width of the film may be about the tow width, and if it is carried on one side, it can be unwound well after being wound on a bobbin.

As in the case of the powder adhesion, the position of supporting may be any place after the resin is uniformly impregnated, but when the cross-sectional shape is controlled, it is desirable after the shape control.

The present invention will be further described with reference to the drawings. FIG. 1 is a side view showing an example of a basic process for manufacturing a tow prepreg. In the figure, a tow 2 wound around a bobbin is pulled out from a creel 1, and the tow 2 pulled out is passed through a rubbing widening roll 3 and then supplied by a Nelson roll 4 while controlling a traveling speed. A resin discharger 5 having a resin heating tank and a gear pump built therein pushes out the resin and supplies it to a discharge port 7 via a heating pipe 6. At that time, a groove (not shown) provided with the tow 2 widened at the discharge port 7 portion
It is made to pass through the inside to narrow the width and make it a constant width so as to contact with the supplied resin. Then, the resin is permeated into the tow 2 on the resin permeation scraping roll 8. In order to narrow the tow width and to prevent the resin from overflowing during resin penetration or resin penetration due to rubbing, it is preferable that the tow pass band of the resin-penetrating rubbing roll 8 has a groove shape. After that, the filament laterally moving impregnating unit 9 uniformly impregnates the tow 2 which is uniformly impregnated, and at the same time, the fibrous thermoplastic resin 25 supplied from the fibrous thermoplastic resin creel 24 is a thermosetting resin. Is placed on the surface of the reinforcing fiber tow 2 impregnated with. The cooled tow 2 is taken up by the torque motor roll 12 with a constant torque, and finally wound by the winder 14 on the bobbin.

FIG. 2 is a side view showing an example of means for laterally moving the filaments forming the tow by using both expansion and contraction of the tow width. In FIG. 2, reference numeral 15 enlarges the tow width. 16 is a roll for reducing the tow width, and the tow width can be narrowed by inclining the roll.

FIG. 3 is a side view showing an example of means for performing lateral movement of the filaments forming the tow by using both twisting of the tow and expansion of the tow width. In FIG. Shows the ingredients.

FIG. 4 is a side view showing an example of means for laterally moving the filaments forming the tow by using folding of the tow and expansion of the tow width. In FIG. 4, the tow 2 is a folding guide 19. It gradually folds and is completely folded by a pair of vertically standing rolls 18.

FIG. 5 is a front view showing an example of means for controlling the cross-sectional shape of the tow by narrowing the tow width and simultaneously compressing it on the cooling roll. In FIG. By fitting the convex portion provided on the compression roll 22 with a proper gap and passing the tow 2 between them, the toe width is narrowed, and at the same time, the tow 2 is compressed to control the sectional shape of the tow 2. There is.

[0056]

EXAMPLES The present invention will be described more specifically with reference to the following examples. In addition, the unwinding property, the drape property, and the compressive strength after impact were evaluated as follows in this example.

(Unwinding property) A 12-inch bobbin was wound with 300 m of tow prepreg at a tiling angle of 10 ° and set on a freely rotating creel. The tow prepreg was pulled out at a speed of 20 m / min from the bobbin in an atmosphere of 25 ° C. At this time, the case where the yarn was broken and the unwinding was interrupted in the middle was judged as poor, and the case where the yarn was unbroken up to the end was regarded as good.

(Drapeability) A tow prepreg is wound around the side peripheral surface of a cylinder of 80 mmφ in an atmosphere of 25 ° C.
At this time, those that floated up locally without bending along the cylinder and locally bent were regarded as having poor drapeability, and those that smoothly follow the cylinder were considered as good drapability.

(Compressive strength after impact) Tow prepregs were lined up on a drum having a diameter of 640 mm by a filament winding method to form a unidirectional prepreg.
MA (Suppliers of Advanced)
Composite Materials Assoc
iation) SRM2-88 270Lb
-The compressive strength after impact was measured. Curing was performed at 180 ° C. for 2 hours using an autoclave.

Example 1 A tow prepreg was manufactured in the manufacturing process shown in FIG. 1 by using two units shown in FIG. 2 as filament lateral moving means. As a tow, carbon fiber MR60P manufactured by Mitsubishi Rayon Co., Ltd. (tensile elastic modulus 3
10 MPa), one tow is used, the tow 2 is widened to a width of 5 mm or more by a rubbing widening roll 3, preheated to 130 ° C. with a heating roll (not shown), and the bottom of the 4 mm wide groove is adjusted to 0.
A pitch roll 26 having a V-shaped groove with a pitch of 5 mm is used to form filament density in the tow 2 in the width direction, and the groove of the resin discharge port 7 is narrowed to a width of 4 mm from the resin discharge port 7 to one side of the tow 2. The resin was supplied and brought into contact with the resin, and the resin was infiltrated into the tow 2 by rubbing it with the resin infiltration rubbing roll 8. The thermosetting resin was held at 65 ° C. in the tank and discharged from the gear pump through the heating hose 6 from the discharge port 7 at 120 ° C. In the vicinity of the discharge port 7, there is no resin overflow or resin stagnation when the resin comes into contact with the tow or penetrates into the tow, and the resin supplied from the resin discharge device 5 adheres to the tow without stagnation. confirmed.

Then, the tow width expanding and contracting rolls shown in FIG. 2 (fixed without rotating both) were passed through to laterally move the filaments constituting the tow to uniformly impregnate the tow with the resin. . The tow temperature after the resin contact infiltration was 120 ° C. The last roll has a tow width of about 5
After widening to a width of mm, the fibrous thermoplastic resin 25 was arranged and at the same time, the tow was cooled by the cooling roll 10, pulled by the torque motor roll 12 at a constant torque, and then wound by the winder 14.

As the thermosetting resin and the fibrous thermoplastic resin, the resins shown in Table 1 were used. The obtained tow prepreg has a tow width of 3.1 mm (standard deviation 0.095 m).
m), 3 g / m ^{2 of} fibrous thermoplastic resin was arranged on one side, the resin content was 34 ± 1.0% by weight with high accuracy, and the unwinding property of the tow prepreg from the bobbin was also good. . The compressive strength after impact was measured and is also shown in Table 1.

(Example 2) In Example 1, instead of the device shown in FIG. 2 as the filament lateral direction moving means, FIG.
A tow prepreg was produced in the same manner as in Example 1 except that the apparatus shown in FIG. The twisting number by the twisting tool 17 in this case was 10 T / m. The obtained tow prepreg has a tow width of 3.1 mm (standard deviation of 0.10 mm) and a fibrous thermoplastic resin is arranged at 3 g / m ^{2 on} each side, and the resin content is 34 ± 0.9% by weight and high precision. The unwinding property of the tow prepreg from the bobbin was also good. The compressive strength after impact was measured and is also shown in Table 1.

(Embodiment 3) In the first embodiment, a device shown in FIG.
A tow prepreg was produced in the same manner as in Example 1 except that the apparatus shown in FIG. The obtained tow prepreg has a tow width of 3.1 mm (standard deviation of 0.11 mm) and a fibrous thermoplastic resin is arranged at 3 g / m ² per side, and the resin content is 34 ± 0.93% by weight and high accuracy. The unwinding property of the tow prepreg from the bobbin was also good. The compressive strength after impact was measured and is also shown in Table 1.

Comparative Example 1 A tow prepreg was produced in the same manner as in Example 1 except that the fibrous thermoplastic resin was not used. The obtained tow prepreg has a tow width of 3.1 mm.
(Standard deviation 0.095 mm), resin content 34 ± 1.0
The accuracy was as high as wt% and the unwinding property of the tow prepreg from the bobbin was good. The compressive strength after impact was measured and is also shown in Table 1.

(Comparative Examples 2 and 3) A tow prepreg was produced in the same manner as in Example 1 except that the composition of the thermosetting resin was changed to that shown in Table 1. The obtained tow prepreg has a tow width of 3.1 mm (standard deviation 0.095 mm),
The resin content was as high as 34 ± 1.0% by weight and the unwinding property of the tow prepreg from the bobbin was good, but it was lacking in flexibility and had difficulty in drapeability. The compressive strength after impact was measured and is also shown in Table 1.

[0067]

[Table 1]

(Examples 4 to 6 and Comparative Examples 4 to 5) The same operations as in Example 1 were carried out except that the composition of the reinforcing fiber, the thermosetting resin and the fibrous thermoplastic resin were changed to those shown in Table 2. Then, a tow prepreg was produced. The unwinding property, drape property, and compressive strength after impact of the obtained tow prepreg were evaluated, and shown in Table 2 together.

[0069]

[Table 2]

[0070]

According to the tow prepreg of the present invention, not only does it have the same excellent handleability as the conventional tow prepreg using a thermosetting resin as a matrix, but it does not impair the thermal and mechanical properties. It is possible to impart excellent toughness to the obtained molded product. In particular, since it has a high resistance to delamination when it receives an impact, it is suitable for use as a structural material for aircraft. Further, according to the production method of the present invention, an excellent effect that a tow prepreg can be produced with high productivity by precisely controlling the resin content using a hot melt resin and performing efficient uniform impregnation Play.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a manufacturing process of a basic tow prepreg of the present invention.

FIG. 2 shows the lateral movement of the filaments forming the tow,
It is a side view which shows an example of a means which performs expansion and contraction of a toe width together.

FIG. 3 shows the lateral movement of the filaments forming the tow,
It is a side view which shows an example of the means which carries out twisting of a tow and expansion of the tow width together.

FIG. 4 shows the lateral movement of the filaments forming the tow,
It is a side view which shows an example of the means which performs the tow folding and the tow width expansion together.

FIG. 5 is a side view showing an example of means for controlling the cross-sectional shape of the tow by narrowing and simultaneously compressing the tow width on the cooling roll.

[Explanation of symbols]

 1 Creel 2 Toe 3 Scratch widening roll 4 Nelson roll 5 Resin discharge machine 6 Heating tube 7 Discharge port 8 Scratch roll for resin penetration 9 Filament lateral movement resin impregnation roll 10 Cooling roll 11 Guide roll 12 Torque motor roll 13 Guide roll 14 Winder 15 Tow width expanding roll 16 Tow width reducing roll 17 Twisting tool 18 Vertical roll 19 Folding guide 20 Cooling roll 21 Recess 22 Compressing roll 23 Convex 24 Fibrous thermoplastic resin creel 25 Fibrous thermoplastic resin 26 Pitched roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Itoh 4-chome, Sunadabashi, Higashi-ku, Nagoya-shi, Aichi Prefecture 60-90, Product Development Laboratory, Mitsubishi Rayon Co., Ltd. No. 1-60 Inside Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (13)

[Claims] 1. (A) Tensile modulus of 200 GP or less
Reinforcing fiber tows a or above, (B) Tensile modulus 100 GPa
A tow prepreg comprising the following fibrous thermoplastic resin, (C) a thermosetting resin having a viscosity of 3,000 to 100,000 poise at 50 ° C., and (B) being localized on the outer surface thereof. 2. A flattened tow is supplied with a constant amount of resin on at least one side, and at the same time as or immediately after the resin is contacted with the tow, the resin is permeated in the thickness direction of the tow and the filaments constituting the tow are laterally moved. A method for producing a tow prepreg, which comprises uniformly impregnating a resin in a tow, arranging a fibrous thermoplastic resin having a tensile elastic modulus of 100 GPa or less on the surface immediately before or simultaneously with cooling, and then winding. 3. The tow is heated in advance before the resin is quantitatively supplied to at least one surface of the flattened tow.
A method for producing the described tow prepreg. 4. The method of manufacturing a tow prepreg according to claim 2, wherein the tow width is expanded in advance so that it is restricted when contacting with the resin, and the tow width is narrowed to a predetermined width when contacting with the resin. 5. The method of manufacturing a tow prepreg according to claim 2, wherein the resin adhesion amount of the tow is controlled by the discharge amount of the resin discharge machine. 6. The method for producing a tow prepreg according to claim 2, wherein the resin is allowed to penetrate in the thickness direction of the tow by rubbing the resin-attached surface of the tow at the same time as or immediately after the contact of the resin with the tow. 7. Lateral movement of the filaments that make up the tow include folding the tow, expanding the tow width, reducing the tow width,
The method for producing a tow prepreg according to claim 2, which is carried out by at least one means such as twisting the tow. 8. The method of manufacturing a tow prepreg according to claim 2, wherein the tow is brought into contact with a rotating body rotating at a peripheral speed lower than the traveling speed of the tow in the step of uniformly impregnating the resin by laterally moving the filaments forming the tow. . 9. The method of manufacturing a tow prepreg according to claim 2, wherein the tow width is narrowed and compressed at the same time in the cooling step to control the cross-sectional shape of the tow. 10. The method of manufacturing a tow prepreg according to claim 2, wherein the tow width is narrowed and compressed immediately before winding to control the cross-sectional shape. 11. The method for producing a prepreg according to claim 2, wherein the powder is attached to the tow after the resin is uniformly impregnated. 12. The method for producing a tow prepreg according to claim 2, wherein after uniformly impregnating the resin, a separator carrier is supported on one surface of the tow. 13. The method for producing a tow prepreg according to claim 2, wherein the tow prepreg is wound individually after contacting, permeating, uniformly impregnating and cooling the resin using a plurality of flat tows.