JP2971967B2 - Method and apparatus for producing fiber reinforced resin sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a fiber reinforced resin sheet in which continuous fibers are impregnated with a thermoplastic resin.

[0002]

2. Description of the Related Art A method for producing a fiber reinforced resin sheet by hot impregnating a thermoplastic resin into a fiber is disclosed in
As described in -61561, a fiber sheet is heated to a temperature higher than the softening point of a thermoplastic resin, and is passed between a pair of belts including a belt having the thermoplastic resin coating film.
Methods for impregnating a thermoplastic resin are known.

However, Japanese Patent Application Laid-Open No.
In the method described in Japanese Patent Laid-Open Publication No. H10-207, in order to obtain a fiber-reinforced thermoplastic resin sheet having a high resin content, a gap between a pair of belts is widened, and a resin equivalent to the widened belt gap is supplied, and a reinforcing fiber is formed. Is not crushed, so that not only is the impregnation of the resin inside the fiber bundle not sufficient, but also the resin protrudes from between the belts, and the thermal decomposition products of the protruding resin accumulate between the belt and the heat roll, causing the operation to fail. This makes it impossible to produce a fiber-reinforced thermoplastic resin sheet having a high resin content.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method and an apparatus for producing a fiber-reinforced thermoplastic resin sheet having a high resin content and excellent resin impregnation which has solved the above-mentioned disadvantages of the prior art. To provide.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. In the method of manufacturing the sheet, in the final stage in which the thermoplastic resin constituting the resin sheet in the hot-melt impregnation step is in a molten state, the thermoplastic resin powder is directly supplied onto the resin sheet to adjust the resin content of the resin sheet. In a device for producing a fiber-reinforced resin sheet, a method for producing a fiber-reinforced resin sheet, wherein a thermoplastic resin is hot-melted and impregnated with a reinforcing resin by a thermoplastic resin, the thermoplastic resin constituting the resin sheet in the hot-melt impregnation step is An apparatus for producing a fiber-reinforced resin sheet, characterized in that a thermoplastic resin powder is directly supplied onto a resin sheet in a final stage in a molten state.

[0006] The reinforcing fiber used in the present invention is a single or a plurality of fibers known as rovings, yarns and tows, which are aggregates of the filaments constituting the fibers, and the filaments are sufficiently used. And has sufficient strength to pull in contact with the molten thermoplastic resin film under the conditions used. Preferred materials include glass fibers, carbon fibers, and highly elastic synthetic resin fibers, and metal fibers such as inorganic fibers such as silicon carbide fibers, alumina fibers, titanium fibers, boron fibers, and stainless steel fibers can be used.

The synthetic fiber is preferably surface-treated so as to have an adhesive property with the thermoplastic resin to be impregnated, and it is necessary that the properties such as strength do not change with the melting temperature of the thermoplastic resin used. . Examples of the synthetic fibers include aramid fibers (registered trademark “Kepler”).

The glass fiber or carbon fiber may be coated with a surface treatment agent such as a silane-based or titanium-based coupling agent on the fiber surface in order to improve the adhesion to the resin in accordance with the thermoplastic resin used. Is preferred. It is preferable in handling to use a sizing agent so that roving or tow is not loosened during handling.

In the present invention, a plurality of continuous fibers are arranged in parallel in, for example, one direction in the machine direction, are controlled so as not to cross each other, are spread in the width direction, are adjusted to an appropriate thickness, and are formed into a sheet shape. Formed. Specifically, continuous fibers are wound on a plurality of bobbins, and the fibers are fed out from each bobbin while applying an appropriate tension, and are arranged in a line in a line with an appropriate width in a machine direction. It is preferable to arrange them in a sheet through a machine.

Although the thickness of the sheet depends on the thickness of the fibers used, it can be controlled by the arrangement and density of rovings and tows in the width direction. Since the thickness accuracy affects the variation of the impregnation state, it is preferably within ± 10% of the target thickness. In particular, when the thickness is larger than 10 μm, the breakage of the fiber can be prevented.

In the sheet thus obtained, it is necessary that uniform tension is applied to each roving or tow so that each roving or tow does not cross.

Next, when the sheet is impregnated with a thermoplastic resin, the thermoplastic resin used is polystyrene, polyvinyl chloride, high-density polyethylene, polypropylene, nylon, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polysulfone, or the like. Polyether sulfone, polyether ether ketone,
Polyimide or the like is used, but is not limited thereto.
When using these resins, it is preferable to carry out drying in advance.

The thermoplastic resin is melted by an extruder, extruded from a die provided at the tip of the extruder, and applied to the surface of a heated lower belt, for example. The resin temperature is determined according to each resin characteristic so as to form a uniform resin coating film. The width of the resin coating may be equal to or greater than the width of the fiber sheet, and the thickness of the coating is adjusted to an appropriate thickness corresponding to the thickness of the fiber sheet. This thickness is a value experimentally determined by the target setting of the resin content in the finally obtained fiber reinforced resin sheet. On the other hand, since the thickness accuracy greatly affects the resin content in the width direction, the thickness accuracy is preferably ± 10% with respect to the set thickness, more preferably,
It is better to be within ± 5%.

Thus, the fiber sheet, which has been coated with a resin film, is pressed against a roll via, for example, a lower belt, and the impregnation of the fiber with the resin is started. Impregnation is achieved when the resin coating passes between the filaments constituting the fiber sheet and reaches the back surface of the fiber sheet.

The fiber sheet coated with the resin is then pressed against, for example, one or more heating rolls while being sandwiched between the upper and lower belts to improve impregnation, and then pulled out from the impregnating device. The temperature of these heating rolls is equal to or higher than the softening point of the resin to be impregnated. In the present specification, the softening point refers to the lowest temperature that can be measured with a load of 5 kg using a melt index measuring device. The fiber content of the fiber sheet thus obtained is usually from 60 to 90% by weight.

The resin constituting the fiber-reinforced thermoplastic resin sheet immediately after being pulled out from the impregnating device is at or above the softening point. In this state, the fine powder resin is uniformly and continuously applied onto the fiber sheet. The heat of the fiber sheet can fix the resin fine powder on the sheet.
The average particle size of the fine powder resin used at this time is 1 to 2000.
Although it is possible to use a resin having a thickness of μm, it is preferably 30 to 100 μm in consideration of fine adjustment of the fiber content and workability in which nozzles are not clogged during coating. In the case of a spherical shape, the particle size refers to the diameter. In the case of a shape other than a spherical shape, the projected area is calculated by converting the projected area into a circle.

As a means for applying the fine powder resin to the resin sheet, an air pressure feeding type or an electrostatic coating type which dissipates the heat of the fiber sheet is not desirable, and a vibration sieve type, a roll coater type and the like are preferable. In order to prevent heat radiation of the fiber reinforced thermoplastic resin sheet immediately after being pulled out from the impregnating device part, to provide a heat insulating wall from the impregnating device outlet to the fine powder resin supply part, or to actively heat. Providing a furnace is more preferable because it promotes the integration of the resin sheet and the fine powder resin. In this way, 60-90wt
The fiber sheet drawn out of the impregnating device with a fiber content of 10% can be adjusted to a fiber content of 10 to 60% by weight.

Next, the details of the present invention will be described with reference to representative embodiments shown in the drawings.

FIG. 1 is a schematic side view showing an embodiment of the present invention.

As shown in FIG. 1, the manufacturing apparatus for carrying out the method of the present invention comprises a fiber feeding section 1, a supply section 2, a resin impregnating section 3, a fine powder thermoplastic resin supply section 4, and a take-up section 5. .

The fiber feeding section 1 has a function of feeding a required number of continuous fibers 8 wound on a plurality of bobbins 7 attached to a gantry 6. The continuous fibers 8 are horizontally arranged by guide rolls 9, and are arranged at an arbitrary fiber interval and an arbitrary thickness by an aligning machine 10 so that a fiber sheet 11 is formed.
To form The aligning machine 10 has a frame-like frame on which a number of steel wires are stretched, and the continuous fibers 8 are aligned by passing through the gaps between the steel wires one by one.

Next, the fiber sheet 11 is controlled to a uniform tension over the entire width by a tension adjusting roll 13 having a brake 12, and is supplied to the resin impregnated section 3. The surface of the tension adjusting roll 13 is preferably made of rubber or the like so that the tension can be easily adjusted by frictional resistance. The tension is not particularly limited, and it is sufficient that the fiber sheet 11 does not disturb the fibers during the impregnation process of the resin impregnation portion 3. The fiber sheet 11 enters the resin impregnated section 3 and contacts the thermoplastic resin plasticized by an extruder (not shown) via a die 14 with a lower belt 15 having a thin film of the resin applied on the surface thereof. Further, the resin is impregnated by being pressed against the heating roll 17 via the belt 15, and then the heating roll 1 is
8, the resin is impregnated with the resin by being pressed against the heating roll 19 via the lower belt 15 and then enters the fine powder thermoplastic resin supply section 4. Dies 14 and 17,18,19,2
Heats 0, 21, 22, and 23 are heated to a temperature corresponding to the melt viscosity of the thermoplastic resin to be used, and a heat transfer heater or an induction heating roll is suitable as a heating method. The rolls 24 and 25 adjust the tension of the belt.
No heating is required. A pair of rolls facing each of the rolls 17 and 20, the rolls 18 and 21, and the rolls 19 and 22 are provided with a mechanism capable of adjusting the interval between them.
The interval can be changed according to the type of reinforcing fiber used and the content of the reinforcing fiber.

The two rolls 19 and 22 are driven by a motor 26, each roll rotates at the same peripheral speed, and the upper and lower belts are conveyed by the rotation of these rolls.

Next, the fiber sheet 11 is sent to the fine powder thermoplastic resin supply section 4. The fine-powder thermoplastic resin supply section 4 is sent from a thermoplastic resin storage tank 27 to a measuring tank 29 by a transporter 28 to measure a predetermined amount of the thermoplastic resin. Spray evenly and integrate with the thermal energy of the fiber sheet. It is possible to arbitrarily adjust the fiber content of the fiber sheet by adjusting the amount of the thermoplastic resin to be sprayed. The heat retaining device 31 is a furnace using an electric heater or the like as a heat source so that the temperature of the fiber sheet does not decrease due to heat radiation, and is particularly effective when handling a thermoplastic resin having a high softening point. The fiber reinforced resin sheet obtained in this manner is taken up while applying tension by the take-up roll 32 of the take-up section 5, and is taken up by the take-up shaft 34. 33 is a drive motor for the take-up roll 32 and the take-up shaft 34.

[0025]

The present invention will be described below with reference to examples.

Example 1 The specifications of each part of the apparatus shown in FIG. 1 are 100 bobbins, extruder 30 mmφ, width of rolls 17 to 25 400 mm, roll diameter 240 mm, thickness of upper and lower belts 15 and 16 of 0.6.
mm and a width of 350 mm were used. Heat rolls 17 and 2
The gap between the upper belt and the lower belt was adjusted to 0.4 mm by adjusting the intervals between 3, 18, and 21 and between 19 and 22. As the continuous fiber, glass fiber (filament diameter: 13 μm, bundle of 1,800 filaments) was used, and polypropylene resin was used as the thermoplastic resin. The continuous fibers fed from the 100 bobbins were aligned to form a 200 mm wide fiber sheet. On the other hand, a polypropylene resin heated and melted at 200 ° C. by an extruder was applied from a coat hanger die to a lower belt moving at a speed of 2 m / min on a roll 23 heated to 230 ° C. at a coating thickness of 100 μm. The fiber sheet to which a tension of 100 kg is applied is passed between the rolls 17 to 22 heated to 230 ° C. in a state shown in FIG. In order to impregnate the resin and obtain a glass content measurement sample, the operation was continued while winding the fiber-reinforced resin sheet around the winding roll 34. Next, the vibrating sieve 30
100μm at a rate of 110g / min from the resin storage tank
While supplying the polypropylene resin fine powder of m, the resin was uniformly dispersed on the fiber sheet while vibrating the vibrating sieve, and the resin was integrated by the heat of the fiber sheet and wound up on the winding roll. Table 1 shows the fiber content, the resin impregnation state, and the operation state of the two types of fiber reinforced resin sheets thus obtained, together with the operation conditions.

Example 2 A fiber-reinforced resin sheet was obtained by changing the type of resin, the type of fiber, and the operating conditions in Example 1 as shown in Table 1. Table 1 shows the fiber content, the resin impregnation state, and the operation state of the fiber reinforced resin sheet thus obtained, together with the operation conditions.

COMPARATIVE EXAMPLE Using the same apparatus as in Example 1, the heat rolls 17 and 23 were used.
The distance between 18 and 21 and the distance between 19 and 22 are adjusted to make the distance between the upper belt and the lower belt 0.8 mm, and the polypropylene resin coating applied to the lower belt without using the fine powder thermoplastic resin supply unit 4 A fiber reinforced resin sheet was obtained under the same operating conditions as in Example 1 except that the thickness of the resin was 700 μm. Table 1 shows the fiber content, the resin impregnation state, and the operation state of the fiber reinforced resin sheet thus obtained, together with the operation conditions.

[0029]

[Table 1]

[0030]

According to the method and apparatus of the present invention, a fiber-reinforced resin sheet having excellent impregnation can be obtained at an arbitrary fiber content.

[Brief description of the drawings]

FIG. 1 shows a schematic side view illustrating one embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fiber feeding section 2 supply section 3 resin impregnated section 4 fine powder thermoplastic resin supply section 5 take-up section 6 gantry 7 bobbin 8 continuous fiber 9 guide roll 10 aligning machine 11 fiber sheet 12 brake 13 tension adjusting roll 14 die 15 lower belt 16 Upper belt 17 to 23 Heating roll 24 to 25 Belt tension adjusting roll 26 Drive motor 27 Thermoplastic resin storage tank 28 Carrier 29 Measuring tank 30 Vibrating sieve 31 Insulation device 32 Take-up roll 33 Drive motor 34 Winding shaft

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FIB29L 7:00 (72) Inventor Takumi Masuda 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Satoshi Kishi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemicals Co., Ltd. 1190 Kasama-cho, Sakae-ku, Yokohama Mitsui Toatsu Chemical Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B29B 15/10-15/14 B29B 11/16 B29C 67/14

Claims (2)

(57) [Claims] Claims: 1. A reinforcing fiber is hot-melt-impregnated with a thermoplastic resin,
In the method for producing a fiber reinforced resin sheet, in the final stage in which the thermoplastic resin constituting the resin sheet in the hot melt impregnation step is in a molten state, the thermoplastic resin powder is directly supplied onto the resin sheet, and the resin content of the resin sheet is reduced. A method for producing a fiber-reinforced resin sheet, wherein the rate is adjusted. 2. A reinforcing fiber is hot-melt-impregnated with a thermoplastic resin,
In a device for manufacturing a fiber reinforced resin sheet, the thermoplastic resin constituting the resin sheet in the hot melt impregnation step is directly supplied with the thermoplastic resin powder on the resin sheet at a final stage in a molten state. For manufacturing a fiber reinforced resin sheet.