JPH09176346A - Manufacturing method of tow prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tow prepreg uniform in the content of a resin, wide in the set range of the resin content, capable of being controlled in good accuracy and capable of being mass-produced, by supplying a constant amount of a matrix resin to a tow through a nozzle and allowing the tow to pass on the nozzle at a constant speed. SOLUTION: This method for producing a prepreg comprises supplying a matrix resin to a tow through a nozzle in a constant amount e.g. by a method utilizing the gravity, a resin-supplying pump, etc., and the tow is allowed to pass on the nozzle at a constant speed to integrate the tow with the matrix resin. The accuracy of the resin content of the obtained tow prepreg on the basis of a set value is <=±2%, preferably <=±1%. The resin content can be set in a range of 5-50wt.%, preferably 10-40wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to molding of fiber reinforced plastics, especially FW (filament winding method).
The present invention relates to a method for manufacturing a tow prepreg used for molding, braid, woven prepreg, and the like.

[0002]

2. Description of the Related Art Composite materials composed of carbon fiber, glass fiber, aromatic polyamide fiber and other reinforcing fibers and epoxy resin are excellent in specific strength and specific elastic modulus, so that they are used for sports, structural materials such as aircraft, civil engineering. Widely used in fields such as materials and rolls.

In order to produce these composite materials, the reinforcing fibers may be used as they are as a material for processing, but in many cases, they are impregnated with a resin, such as woven prepreg, chopped fiber premix, sheet prepreg and tow prepreg. Often used as an intermediate processing material.

In any case, it is desired to reduce the manufacturing cost of the final product, the composite material molded product, while improving the quality. In particular, controlling the ratio of fibers and matrix resin in a composite material molded product is extremely important for enhancing the physical properties of the composite material molded product, such as strength, elastic modulus, and thermal expansion coefficient, and obtaining a product of stable quality. That is.

Tow prepreg is used for filament winding molding, braid, woven fabric production, etc. When using the tow prepreg as compared with the existing method, there is less fluffing and the yield is high and the work efficiency is high.
Since the resin impregnation step becomes unnecessary, it is possible to reduce the manufacturing cost.

As a method of manufacturing tow prepreg, a resin bath method, a rotating roll method, a paper transfer method and the like are used. The resin bath method is a method in which the tow is passed through the resin bath to impregnate it with a matrix resin, and then the excess matrix resin is squeezed out by an orifice, a roll or the like to adjust the resin content. However, this method causes friction with the tow when the excess matrix resin is squeezed out by an orifice, a roll, etc., resulting in damage to the tow accompanied by yarn breakage, fuzzing and the like. Moreover, since the resin content is adjusted by squeezing out the matrix resin, it is difficult to adjust the resin content with an accuracy of 1%, and it is difficult to manufacture a resin content of 40 wt% or less. Further, since the tow is passed directly through the resin bath, there is a problem that the inside of the resin bath is soiled by fluff or the like.

The rotary roll method is a transfer roll type impregnation method in which a matrix resin layer is formed on a rotary roll and transferred to a tow, for example, an impregnation method with a rotary drum having a doctor blade. Regarding the method, it is difficult to finely adjust the gap between the doctor blade and the rotating roll, and it is difficult to maintain the uniformity of the resin content due to the variation of the transfer rate due to the non-uniformity of the yarn width of the tow. Further, due to the friction between the rotating roll and the tow, the tow is damaged due to yarn breakage, fluffing, and the like, and the inside of the resin bath is soiled as in the above method.

The on-paper transfer method is an impregnation method in which a matrix resin layer is formed on paper and transferred to a tow. However, this method also has a resin content due to variations in transfer rate due to non-uniform yarn width of the tow. It is difficult to maintain the uniformity of the amount, and due to friction at the time of resin transfer, damage to the toe occurs due to yarn breakage, fluffing, etc. as in the above method.

The tow prepreg produced by these production methods has low quality stability because it is difficult to maintain the weight ratio of the fiber and the matrix with high accuracy, and also to prevent the tow from being damaged by friction. There are problems such as high manufacturing cost due to low production speed.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems in the conventional tow prepreg manufacturing method,
Provided is a method for producing a tow prepreg which has a uniform resin content, a wide range of setting of an arbitrary resin content, and which can be accurately controlled, and which can be mass-produced.

[0011]

The above-mentioned object of the present invention can be achieved by the following method for producing a tow prepreg.
That is, the present invention relates to a method for producing a tow prepreg, characterized in that a constant amount of matrix resin is supplied to the tow through a nozzle, and the tow passing over the nozzle has a constant speed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The manufacturing method of the present invention will be described in more detail below. An example of the manufacturing process of the tow prepreg according to the present invention is shown in FIG. In the figure, 1 is a creel,
2 is a guide pulley, 3 is a first preheating pulley, 4 is a second
Preheating pulley, 5 first heat pulley, 6 second heat pulley, 7 cooling pulley, 8 nozzle, 9 resin feed pump, 10 resin tank, 11 yarn speed sensor, 12 yarn speed controller, Reference numeral 13 is a winding device, and 14 is a drum.

In FIG. 1, the tow sent out from the creel 1 passes through a guide pulley 2 and a first preheating pulley 3 and is heated to a predetermined temperature, and at the same time, the tow has a flat cross section. The tow that has passed through the first preheating pulley 3 is passed through the second preheating pulley 4.

The matrix resin is stored in the resin tank 10 and is sent to the resin supply pump 9 when the tow prepreg is manufactured. The resin tank 10 is preferably a closed type so that the pot life of the matrix resin can be extended. The matrix resin can be heated by heating the resin tank 10 or the nozzle 8. The matrix resin supplied by the constant quantity supply device is supplied to the tow passing through the second preheating pulley 4. After the matrix resin is supplied, the matrix resin and the tow are heated to a target temperature through the first heat pulley 5 and the second heat pulley 6, and the tow is flattened to effectively produce a tow prepreg having a uniform resin content. You can

The first heat pulley 5 installed on the matrix resin supply surface side of the tow forces the matrix resin supplied on the tow from the supply surface side to the inside of the tow and the other surface of the tow. Can be impregnated,
Further, the matrix resin remaining on the other surface of the tow due to the impregnation operation by the first pulley 5 is pushed back to the inside of the tow again by the second pulley 6 installed on the surface opposite to the matrix resin supply surface of the tow, and is forced. It can be impregnated, and by such an operation, a tow having a uniform resin content can be obtained.

The tow prepreg passes through the cooling pulley 7 to retain the cross-sectional shape of the prepreg, and is then wound around a drum 14 connected to a winding device 13. Although the yarn speed sensor 11 is installed on the cooling pulley 7, it may be installed at any position as long as the speed of the tow passing through the nozzle 8 can be substantially measured.

The yarn speed sensor 11 and the drum 14 of the winding device 13 are respectively connected to the yarn speed control device 12, and the yarn speed sensor 11 controls the winding speed to a target yarn speed. In FIG. 1, a creel, a guide pulley, a preheating pulley, a nozzle, a heat pulley, a speed sensor,
The number of drums or the like is one or two, but more than one drum may be installed in parallel to manufacture a plurality of tow prepregs at the same time.

In the present invention, in order to obtain a tow prepreg having a uniform resin content, it is necessary to constantly supply the tow with the matrix resin at a constant ratio. That is, the yarn speed of the tow passing through the nozzle is controlled to be constant, and a predetermined amount of matrix resin for the tow is supplied at a constant speed through the nozzle to combine the tow and the matrix resin, thereby obtaining a uniform resin content. Can be obtained.

According to the above method, it is possible to obtain a tow prepreg having an accuracy of ± 2% or less, preferably ± 1% or less with respect to the set value of the resin content. The setting range of the resin content is not particularly limited, but it can be usually 5 to 50 wt%, preferably 10 to 40 wt%. If the resin content exceeds 50 wt%, it is difficult to control the resin content accurately due to dripping, and if it is less than 5 wt%, it becomes difficult to uniformly impregnate the tow with the matrix resin. .

Regarding the method of controlling the resin content, the tow prepreg having an arbitrary resin content can be obtained by increasing or decreasing the yarn speed or the supply amount of the matrix resin. The yarn speed can be controlled by any means, but in order to prevent excessive tension on the tow in order to prevent yarn breakage and fluff generation, a yarn speed sensor can be used before or after the matrix resin is supplied. When the yarn speed exceeds a set value, it is preferable to maintain a constant yarn speed by reducing the output of the transfer means such as the winder.

In the present invention, since the matrix resin is uniformly impregnated, the yarn speed is controlled within ± 5% of the target yarn speed, preferably within ± 3%. It is possible to install a roll that winds at a constant speed between the drum and the heat pulley,
The tow prepreg between the roll and the winding drum is unnecessarily tensioned and may not be preferable depending on the kind of the reinforcing fiber.

The yarn speed has a preferable range depending on the type of reinforcing fiber. In the case of carbon fiber, usually 5 to 200 m / m
It is possible to work at a yarn speed of in, preferably 5 to 150 m / min. If the yarn speed of the carbon fiber is less than 5 m / min, the productivity of the tow prepreg is poor, which is not preferable.
If it exceeds 00 m / min, yarn breakage or fluffing tends to occur. Further, the yarn speed has a preferable range depending on the viscosity of the matrix resin, particularly the viscosity at the time of supplying or impregnating the matrix resin.

The viscosity of the matrix resin is 0.01 to 10
In the case of poise, the yarn speed can be usually 5 to 200 m / min, preferably 5 to 150 m / min. When the viscosity of the matrix resin exceeds 10 poise and is 100 poise or less, it is usually 5 to 150.
It is possible to work at a yarn speed of m / min, preferably 5-120 m / min.

The viscosity of the matrix resin is 100 pois
When e is more than 300 and less than 300 poise, usually 5
It is possible to work at a yarn speed of 120 m / min, preferably 5-100 m / min. When the viscosity of the matrix resin is more than 300 poise, the yarn speed can be slowed, and when the viscosity is 0.01 poise, it can be sped up, but it is not preferable because dripping tends to occur.

As a method for supplying a fixed amount of matrix resin, any method such as gravity or a resin supply pump may be used. When using gravity, it is preferable to adjust the supply amount with a flow meter, a flow control valve, or the like. When controlling the ratio of the fiber and the matrix resin with high accuracy, it is preferable to use a pump having excellent quantitative supply property. There is no limitation on the kind of the pump having an excellent quantitative supply property, but examples thereof include a rotary pump, a plunger pump, a gear pump, a mono pump, a centrifugal pump, a cascade pump, a midland pump, and a diaphragm pump.

The resin content in the tow prepreg can be easily controlled by adjusting the supply amount of the matrix resin because the yarn speed is constant. The amount of matrix resin supplied is (yarn speed) × (weight of tow per unit length) ×
(Set value of resin content (wt%)) / [100- (set value of resin content (wt%))], but usually 0.1
~ 240 g / min, preferably 1-100 g / min
Is set in the range.

The reinforcing fiber applied as the tow is not particularly limited, but carbon fiber, glass fiber, alumina fiber, silicon carbide fiber, boron fiber, aramid fiber and the like are specifically mentioned, and carbon fiber is particularly preferably used. The matrix resin is not particularly limited, but a thermosetting resin, particularly an epoxy resin, is preferable for the tow prepreg because it is easy to handle.

The matrix resin may be mixed or dispersed with a curing agent and a curing accelerator in advance before being supplied to the tow. The method of supplying the matrix resin supplied in a fixed amount to the tow is not particularly limited, but a method of forcibly dropping a certain amount of the matrix resin into the tow and forcibly impregnating it by passing through the pulley is available. preferable.

To facilitate the impregnation of the matrix resin into the tow by heating the matrix resin and / or the tow before or after the supply of the matrix resin, with the upper limit of the temperature being 30 ° C. or lower than the curing temperature of the matrix resin. The viscosity of the matrix resin can be easily stabilized by performing the treatment at 15 to 150 ° C., preferably at 15 to 90 ° C.

The matrix resin having a high viscosity is usually added in an amount of 0.01 to 300 p by heating or treatment such as solvent dilution.
Oise, preferably 0.1 to 100 poise, most preferably 0.1 to 10 poise in a low viscosity range. Particularly, if it is within the above range at 15 to 30 ° C., the matrix resin is preferable because it is easy to handle. If the viscosity of the matrix resin exceeds 300 poise, impregnation into the tow is insufficient, and the fluff of the tow is likely to occur, and if the viscosity is less than 0.01 poise, dripping may occur easily, which is not preferable. .

The ease with which the matrix resin is impregnated into the tow varies depending not only on the viscosity of the matrix resin but also on the filament diameter of the tow and the sizing agent used. A tow with a small filament diameter or a tow using a hard sizing agent is difficult to impregnate with the matrix resin.

Heating the tow before feeding the matrix resin,
It can be done either during or after supply,
In the case of the tow that is difficult to impregnate as described above, the tow is usually fed by a preheating pulley before feeding the matrix resin by 15 to 150.
It is preferable to heat to ℃, preferably 15 to 90 ℃.

Although any method of heating the tow may be used, it is preferable to use a preheat pulley and a heat pulley capable of simultaneously heating the tow, flattening the tow, and impregnating the matrix resin. The use of the pulley can effectively promote the impregnation of the matrix resin. It is also easy to manufacture two or more tow prepregs by arranging two or more thermal pulleys in parallel, which saves space and facilitates mass production.

In order to obtain a tow prepreg having a uniform resin content, it is also affected by the sectional shape of the groove of the pulley.
The cross-sectional shape of the groove of the preheating pulley and the heat pulley can be any of U-shape, V-shape, inverted U-shape, U-shape with flat bottom, etc., but U-shape with flat bottom The ones that can be flattened to a uniform thickness and can be uniformly impregnated with the matrix resin are preferably used.

The width-thickness ratio of the flat tow is usually 1
It is considered that 0 to 1000: 1, preferably 30 to 100: 1 is good. Further, in the present invention, it goes without saying that a drum, a roll or the like can be used instead of the pulley as long as the same effect as described above can be obtained.

[0036]

EXAMPLES Examples will be shown below, but it goes without saying that the present invention is not limited thereto.

Example 1 As tow, carbon fiber T700-12K manufactured by Toray Industries, Inc. (trade name, number of filaments: 12000, weight per unit length of tow: 0.8 g / m), matrix resin: 2
A tow prepreg was manufactured by the manufacturing process shown in FIG. 1 using a thermosetting epoxy resin having a viscosity of 30 poise at 5 ° C. and a viscosity of 0.4 poise at 80 ° C. and a curing temperature of 130 ° C.

The yarn speed of the tow passing over the nozzle for supplying the matrix resin was 100 m / min. The resin supply amount is 14.1 to 53.4 g / min, and the resin content is 40 wt%, 31 wt%, 30 wt%, 20 wt%, 1
A 5 wt% tow prepreg was produced.

At this time, 80 ° C. before and after the supply of the epoxy resin
A preheated pulley and a heated pulley which were heated to the above were installed to facilitate impregnation with the epoxy resin by heating. The actual resin content of the tow prepreg thus produced was measured. The results are shown in Table 1.

A tow prepreg having a resin content of 30 wt% was used to form a cylindrical pipe of 60 g (fiber volume content 61.6 vol%) by the filament winding method. The weight and the volume fraction of the yarn in the molded body of the obtained cylindrical pipe were measured. Table 2 shows the results. In addition, the number of times of measurement of each value was 5, and the average value and the variation value are shown in Tables 1 and 2.

Comparative Example 1 A tow similar to that of Example 1 was impregnated with the same matrix resin as that of Example 1 using a rotating drum having a doctor blade, and a tow prepreg having the same resin content as that of Example 1 was used. Was manufactured, and the resin content of the obtained tow prepreg was measured. The results are shown in Table 1.

A tow prepreg having a resin content of 30 wt% was used to form a cylindrical pipe of 60 g in the same manner as in Example 1, and the weight and the volume fraction of the yarn in the formed body were measured. The results are shown in Table 2.

Comparative Example 2 A tow similar to that of Example 1 was impregnated with the same matrix resin as that of Example 1 by a resin bath method to produce a tow prepreg having a resin content similar to that of Example 1. The resin content of the tow prepreg was measured. The results are shown in Table 1.

[0044]

[Table 1]

[0045]

[Table 2]

As is clear from Table 1, the tow prepreg produced by the production method of the present invention has a property that the resin content is extremely uniform and the resin content is stable over a wide range. . Further, as is apparent from Table 2, the molded product obtained from the tow prepreg manufactured according to the present invention has a property that the variation in weight is small and the yarn volume fraction is uniform.

[0047]

According to the present invention, the resin content can be easily and accurately controlled within a wide range to an arbitrary set value. Further, in the present invention, since the resin bath or the like is not used, the resin tank of the matrix resin is not contaminated by the fluff of the reinforcing fiber and the yarn breakage, and the maintenance management of the apparatus such as the cleaning of the resin tank is easy. Since the tow prepreg obtained according to the present invention has a uniform resin content, the molded product using the tow prepreg has a stable weight and does not have uneven thickness. It is possible to obtain those having stable physical properties such as.

[Brief description of the drawings]

FIG. 1 is a schematic view of a tow prepreg manufacturing process according to the present invention.

[Explanation of symbols]

1: Creel, 2: Guide pulley, 3: First preheating pulley, 4: Second preheating pulley, 5: First heating pulley,
6: second heat pulley, 7: cooling pulley, 8: nozzle,
9: resin supply pump, 10: resin tank, 11: yarn speed sensor, 12: yarn speed control device, 13: winding device, 1
4: Drum.

Claims (1)

[Claims] 1. A method of manufacturing a tow prepreg, comprising supplying a constant amount of matrix resin to a tow through a nozzle, and making the tow passing over the nozzle at a constant speed.