JPH09277387A - Manufacture of fiber reinforced thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a thermoplastic resin sheet containing a specific weight of fibers without making molten resin flow out by a method wherein preliminary molded product containing a reinforcing fiber and a thermoplastic resin is preliminarily molded, and the preliminarily molded product is melted by heating via a heat resistant releasing article having a higher melting point than a melting point of the thermoplastic resin. SOLUTION: A preliminary molded product containing reinforcing fiber and a thermoplastic resin is molded, and a heat resistant releasing article having a higher melting point than a softening point or a melting point of the thermoplastic resin is arranged on an upper surface and a lower surface of the preliminary molded product. Then, the preliminary molded product is melted via the heat resistant releasing article at a temperature higher than the softening point or the melting point of the thermoplastic resin under being pressurized. Then, the melted preliminary molded product is solidified by cooling at a temperature of under the softening point or the melting point of the thermoplastic resin under being pressurized. The preliminary molded product is a deposite of a film piece, and a ratio by wt. of the reinforcing fiber and the thermoplastic resin which are contained in the preliminary molded product is 85/15 to 50/50.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a fiber-reinforced thermoplastic resin sheet. More specifically, the present invention is a fiber-reinforced thermoplastic resin that satisfies the impregnating property and the productivity at the same time, does not cause the molten resin to flow out, can obtain a desired fiber weight content, and can be implemented at low cost. The present invention relates to a method for manufacturing a resin sheet.

[0002]

2. Description of the Related Art In recent years, fiber-reinforced thermoplastic resin sheets have been
Widely used as an intermediate for molding or as a molded product. In particular, the molding intermediate is called a stampable sheet, for example, cut into a predetermined shape, heated to a temperature near or above the softening point or melting point of the thermoplastic resin by far-infrared heating or the like, and then heated to a predetermined temperature. Placed in a mold, and pressed and cooled to solidify to form a final molded product.

[0003] Such a molding intermediate has heretofore been used as a matte material (for example, a chopped strand mat) of reinforcing fibers (for example, glass fiber, carbon fiber) or an aligned product, and a powder of a thermoplastic resin. , A film or sheet is melt-impregnated at a temperature higher than at least the softening point or melting point of the thermoplastic resin.

As a conventional method for producing the molding intermediate, for example, the following method can be mentioned.

A. Press molding: A mold having excellent fitting accuracy for mounting on a press and having a heating and cooling device is heated to a temperature higher than at least a softening point or a melting point of a thermoplastic resin by a heat medium. Reinforcing fibers and a thermoplastic resin sheet or thermoplastic resin powder are placed in this mold, and molten and impregnated by heating and pressing. Next, the mold is cooled with a refrigerant, and the molten resin is pressed and solidified by cooling to obtain a fiber-reinforced thermoplastic resin sheet.

B. Mold transfer cooling molding: A mold attached to a pair of presses capable of heating and / or cooling and having excellent fitting precision is used. First, this mold is attached to one of the presses, and after heating to a temperature higher than at least the softening point or melting point of the thermoplastic resin, the reinforcing fiber and the thermoplastic resin sheet or the thermoplastic resin powder are placed in this mold. Melt and impregnate by heating and pressurizing. Next, the mold in which the reinforcing fibers and the molten resin are arranged is transferred to the other press, and the molten resin is pressed and solidified by cooling to obtain a fiber-reinforced thermoplastic resin sheet.

C. Double belt press molding: An apparatus called a double belt press machine having an endless belt and an auxiliary device for heating and / or cooling is used. Reinforcing fiber and thermoplastic resin sheet or thermoplastic resin powder,
The fiber-reinforced thermoplastic resin sheet is obtained by placing in a double-belt press machine, melt-impregnated by heating and pressing, and continuously pressing and cooling to solidify.

D. Roll forming: An apparatus having at least a pair of heating rolls and at least a pair of cooling rolls is used. The reinforcing fiber and the thermoplastic resin sheet or the thermoplastic resin powder are melt-impregnated by heating and pressurizing with a heating roll, and then pressurized and cooled with a cooling roll to be solidified to obtain a fiber-reinforced thermoplastic resin sheet.

However, each of the above methods has the following problems.

In press molding and mold conveying cooling molding, (a) the mold is heated at least near the softening point or melting point of the thermoplastic resin, and (b) the pressure is maintained at least until the resin solidifies. The mold must be cooled. Therefore, heating and cooling take a very long time, and it is difficult to improve productivity. On the other hand, in order to increase the productivity, many molds are required, which causes an increase in the cost required for equipment.

In the double-belt press molding, continuous production is possible by using an apparatus having an endless belt (usually a metal belt is used) and an auxiliary device for heating and / or cooling ( That is, it is excellent in productivity). However, in this method, when pressure and heat are applied to impregnate the reinforcing resin with the thermoplastic resin, the melted thermoplastic resin flows out from the widthwise end of the metal belt. As a result, not only the fiber weight content, which is an important characteristic of the fiber-reinforced thermoplastic resin sheet, fluctuates, but also the spilled resin pollutes the device, it takes time to clean the device, and the width direction of the obtained sheet There are various problems such as the need to remove the end portion because the thickness of the end portion is insufficient. On the other hand, when the melt impregnation is performed at a low pressure, the impregnation of the reinforcing resin with the thermoplastic resin becomes insufficient, and voids are present in the obtained fiber-reinforced thermoplastic resin sheet, and the wettability between the reinforcing fiber and the thermoplastic resin is insufficient. It causes problems such as That is, the impregnation property of the thermoplastic resin into the reinforcing fiber is insufficient. Such insufficient impregnability is due to, for example, stamping molding to remelt the resulting sheet,
Even if it is pressurized and cooled, it cannot be sufficiently improved. Further, at present, the double belt press device is
It is extremely expensive as compared with a press device and the like, and is also extremely disadvantageous in terms of manufacturing cost.

Roll forming is excellent in productivity as in the double belt press forming. Further, in recent years, it has been attempted to prevent the molten resin from flowing out by performing groove processing on the roll. However, such grooving is expensive, and it is not possible to sufficiently prevent the resin from flowing out. Therefore, the roll molding has a problem that the molten resin flows out, as in the above-mentioned double belt press molding. Further, roll forming is difficult to form under high pressure such as press forming, and thus the impregnating property of the obtained sheet is often insufficient.

As described above, the fiber-reinforced thermoplastic resin satisfying both the impregnating property and the productivity at the same time, the molten resin does not flow out, the desired fiber weight content is obtained, and it can be carried out at low cost. The method for manufacturing the sheet has not been obtained yet.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and an object of the present invention is to satisfy the impregnating property and the productivity at the same time and to flow out the molten resin. It is an object of the present invention to provide a method for producing a fiber-reinforced thermoplastic resin sheet which can be carried out at a low cost and which can achieve a desired fiber weight content without being subjected to the above.

[0015]

Means for Solving the Problems As a result of intensive studies, the present inventors have preformed a preform containing reinforcing fibers and a thermoplastic resin, and have a softening point or a melting point of the thermoplastic resin. It was found that the above object can be achieved by heating and melting a preform through a heat-resistant release article having a higher melting point to form a fiber-reinforced thermoplastic resin sheet, and completed the present invention. .

The method for producing a fiber-reinforced thermoplastic resin sheet of the present invention is a method for producing a fiber-reinforced thermoplastic resin sheet containing reinforcing fibers and a thermoplastic resin; Molding a preform containing the same; arranging a heat-resistant release article having a melting point higher than the softening point or melting point of the thermoplastic resin on at least the upper surface and the lower surface of the premold; And, and
Melting the preform through the heat-resistant release article at a temperature equal to or higher than the softening point or melting point of the thermoplastic resin;
Cooling and solidifying the molten preform under pressure and at a temperature below the softening point or melting point of the aged plastic resin.

In a preferred embodiment, the preform has a length of 5 mm to 100 mm and a width of 5 mm to 30 mm.
And a deposit of thin film pieces having a thickness of 0.05 mm to 0.3 mm, and the weight ratio of the reinforcing fiber and the thermoplastic resin contained in the preform is 85/15 to 50/50.

In a preferred embodiment, the preform has a width of 5 mm to 30 mm and a thickness of 0.05 mm to.
It is a woven fabric laminate formed from a 0.3 mm tape-like material, and the weight ratio of the reinforcing fibers and the thermoplastic resin contained in the preform is 85/15 to 50/50.

In a preferred embodiment, the preform is a unidirectional reinforcing sheet laminate selected from a unidirectional laminate, an orthogonal laminate, a cross laminate, and a combination thereof. The weight ratio of the reinforcing fiber and the thermoplastic resin contained in the body is 85/15 to 50/50.

In a preferred embodiment, the preform is a combination of at least two preforms.

[0021] In a preferred embodiment, the heat-resistant release article has a box shape.

In a preferred embodiment, the heat-resistant release article is a metal foil having a thickness of 0.05 mm to 1.0 mm.

In a preferred embodiment, the heat-resistant release article is a metal foil having a release treatment on the surface in contact with the preform.

[0024] In a preferred embodiment, the melting step and the cooling and solidifying step are carried out by using a press machine.

In a preferred embodiment, the melting step and the cooling and solidifying step are performed using a double belt press type device.

In a preferred embodiment, the melting step and the cooling and solidifying step are carried out by using an apparatus having a heating roll and a cooling roll.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, the term "preformed product" refers to any molded product containing reinforcing fibers and a thermoplastic resin and capable of forming a final sheet (that is, a fiber-reinforced thermoplastic resin sheet). Includes.

The reinforcing fiber is not particularly limited, but typical examples thereof include inorganic fibers such as carbon fiber, silicon carbide fiber and glass fiber; metal fibers such as boron fiber; organic fibers such as aramid fiber. From the point of view of cost and elastic modulus and mechanical strength of the obtained sheet, glass fiber,
Inorganic fibers such as carbon fibers are preferred. These fibers are
It is preferable that the continuous fibers are aligned and sufficiently opened before use.

The thermoplastic resin is not particularly limited, but typical examples are nylon 6, nylon 12, nylon 6
6, polyamide resins such as nylon 46; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyolefin resins such as polyethylene and polypropylene; polyetherketone resins, polyphenylene sulfide resins, polyetherimide resins, polycarbonate resins, etc. To be

Representative examples of particularly preferable thermoplastic resins are as follows. These can be appropriately used depending on the application (or desired characteristics) of the sheet: (1) Low cost, fluidity during molding, water resistance, hot water resistance,
Alternatively, when chemical resistance is required, a polyolefin resin is preferable. Polypropylene is particularly preferred because it is readily available. In the present invention, acid-modified polypropylene is most preferable. This is because it is particularly excellent in the adhesiveness with the reinforcing fibers described below; (2) When friction wear resistance, oil resistance, or long-term heat resistance properties are required, polyamide resins are preferable, and nylon 6 is particularly preferable; And (3) heat resistance, mechanical strength, creep characteristics, chemical resistance,
Alternatively, when oil resistance is required, a polyester resin is preferable, and polyethylene terephthalate is particularly preferable.

The weight ratio of the reinforcing fiber and the thermoplastic resin contained in the preform is preferably 85/15 to.
50/50, more preferably 80/20 to 60/40. By containing the reinforcing fiber and the thermoplastic resin in such a range, a sheet having particularly excellent elastic modulus and strength can be obtained.

The preform may contain additives such as a heat deterioration preventing agent, an oxidation deterioration preventing agent, an ultraviolet absorber and a hydrolysis preventing agent, if necessary. The content of these additives is
It can change depending on the purpose.

The preform is preferably obtained by impregnating the above-mentioned reinforcing fibers with the above-mentioned thermoplastic resin and forming into a predetermined shape. The molding method of the preform can be changed depending on the shape of the preform obtained. A preferable method for forming the preformed body will be specifically described below.

Laminate of woven fabric formed from tape-like material: (i) A reinforcing resin is impregnated with a thermoplastic resin to obtain a resin-impregnated sheet. The thickness of the resin-impregnated sheet is preferably 0.
It is from 05 mm to 0.3 mm. (ii) Cut the resin-impregnated sheet into a tape shape. The width of the tape-like material is preferably width 5
mm to 30 mm. (iii) The resulting tape is woven to obtain a woven fabric. (iv) By laminating this fabric,
The preform used in the present invention is obtained.

Deposition of thin film pieces: (i) A tape-like material is obtained in the same manner as in the case of the above-mentioned woven fabric laminate. (ii) This tape-like material is cut into a predetermined length to obtain a thin film piece. The length of the thin film piece is preferably 5 mm to 10
It is 0 mm. (iii) When a thin film piece is used as the preform, the heat-resistant release article described below is preferably box-shaped. After depositing a predetermined amount of the thin film pieces in the box-shaped product, the upper part of the box is covered with a sheet-shaped heat-resistant release article, and the final sheet is formed.

Laminated body of unidirectional reinforcing sheet: (i) The continuous fibers are sufficiently aligned and opened so that the arranging direction of the reinforcing fibers is aligned in one direction. (ii) A unidirectional reinforcing sheet is obtained by impregnating reinforcing fibers aligned in one direction with a thermoplastic resin. (iii) By laminating the obtained unidirectional reinforcing sheet, a preform for use in the present invention can be obtained; or (i) a tape-shaped article obtained in the same manner as in the case of the above-mentioned woven fabric laminate. , Align in one direction. By laminating the tape-shaped materials aligned in one direction, the preform used in the present invention can be obtained.

The unidirectional reinforcing sheet is laminated in one direction,
It is selected from orthogonal, oblique and combinations thereof. Here, "one direction" means that the directions in which the reinforcing fibers (or tapes) are arranged are parallel; "orthogonal" means that the directions in which the reinforcing fibers (or tapes) are arranged are right angles. And, "oblique" means that the direction in which the reinforcing fibers (or tapes) are arranged has an angle other than a right angle.

The above-mentioned preforms can be used in an appropriate combination. For example, a woven fabric laminate and a stack of thin film pieces may be used in combination, or a woven fabric laminate and a unidirectional reinforcing sheet laminate may be used in combination.

The heat-resistant release article used in the present invention has a melting point higher than the softening point or melting point of the thermoplastic resin. That is, the heat-resistant release article does not melt at the softening point or melting point of the thermoplastic resin and has appropriate rigidity. If the rigidity is insufficient, the heat-resistant release article is likely to be torn, twisted, or wrinkled when the final sheet is formed. Therefore, the thermoplastic resin may flow out when the final sheet is formed, and as a result, the quality of the obtained sheet may be insufficient.

The shape of the heat-resistant release article can be changed depending on the shape of the preform and the desired characteristics of the sheet to be obtained, but is typically sheet-like, box-like, or bag-like. When the heat-resistant release article has a box shape or a bag shape, the outflow of the thermoplastic resin at the time of forming the final sheet can be significantly prevented.
When the heat-resistant release article has a sheet shape, the thermoplastic resin can be remarkably prevented from flowing out at the time of forming the final sheet by folding the ends to form a wall. Specific examples of the material constituting such a heat-resistant release article include:
Examples thereof include glass fiber reinforced Teflon sheet (hereinafter referred to as Teflon glass sheet) and metal foil. As the metal foil, copper foil, aluminum foil and the like, which are recyclable and inexpensive, are preferable. These may be used as they are, or may be molded into a predetermined shape (for example, a box shape) as needed.

Materials that make up the heat resistant release article (eg,
The thickness of the Teflon glass sheet and the metal foil) is preferably 0.01 mm to 1.0 mm, more preferably 0.05 m.
It is m-1.0 mm. If the thickness is less than 0.01 mm,
When the final sheet is molded, the heat-resistant release article tears and twists,
Or wrinkles are likely to occur. Therefore, the thermoplastic resin may flow out when the final sheet is formed, and as a result, the quality of the obtained sheet may be insufficient. If the thickness exceeds 1.0 mm, the weight of the heat-resistant release article increases, so that the force required for peeling the heat-resistant release article after forming the final sheet increases. Therefore, the operability is often insufficient (for example, the burden of the peeling operation increases). Further, in many cases, an excessive load is applied to the forming device for the final sheet.

Preferably, the heat-resistant release article can be subjected to a release treatment. Particularly preferably, the surface of the heat-resistant release article that contacts the preform can be subjected to a release treatment. By performing the release treatment, the releasability between the obtained sheet and the heat-resistant release article is remarkably improved, and as a result, the operability and the productivity are remarkably improved. Although the method of mold release treatment is not particularly limited, the following method treatments are typically included:
Application of a release agent by spraying or brushing; dipping on a release agent; use of a heat-resistant release article containing a release agent; selection of a thermoplastic resin (for example, silicone resin) having excellent release properties .

The heat-resistant release article is placed on at least the upper surface and the lower surface of the preform, and used for forming the final sheet. Here, "the heat-resistant release article is arranged on at least the upper surface and the lower surface of the preform" means that the heat resistance is maintained between the preform and the mold (or roll) of the apparatus for forming the final sheet. It means that a release article is present. That is, it means that the mold (or roll) and the preform are not in direct contact with each other. Therefore, the description that "the heat-resistant release article is arranged on at least the upper surface and the lower surface of the preform" means, for example, that the thin film piece is deposited in a predetermined amount in a box-shaped heat-resistant release article to obtain the final sheet. The case of being used for molding is also included.

The preform on which the heat-resistant release article is placed is formed into a sheet by a known method. Specific examples of the sheet forming method include press forming, mold conveying cooling forming, double belt press forming, and roll forming.

In any of the sheet molding methods, the preform is melted under pressure and at a temperature not lower than the softening point or melting point of the aforesaid thermoplastic resin through the heat-resistant release article. Melting conditions may vary depending on the molding method and the desired properties of the final sheet, but typically the pressure during melting is preferably from ² to 10 kgf / cm ² ; the mold (or roll) during melting. ) The temperature is preferably (melting point or softening point) to (melting point or softening point + 50 ° C.);
And the melting time is preferably 2 to 4 minutes.

Next, the melted preform is cooled and solidified under pressure at a temperature lower than the softening point or melting point of the above-mentioned ripening resin to obtain a final sheet (that is, a fiber-reinforced thermoplastic resin sheet). . Cooling and solidifying conditions may vary depending on the molding method and the desired properties of the final sheet, but typically the pressure during cooling and solidifying is preferably 20.
˜40 kgf / cm ² ; mold (or roll) temperature during cooling and solidification is preferably 50 to 120 ° C .;
And the melting time is preferably 1 to 3 minutes.

Such a fiber-reinforced thermoplastic resin sheet can be suitably used for molding intermediates (for example, stamping molding intermediates), molded products (for example, molds, panels) and the like.

The operation will be described below.

According to the present invention, the preform containing the reinforcing fiber and the thermoplastic resin is preformed, and the heat-resistant release article having a melting point higher than the softening point or the melting point of the thermoplastic resin is used. The preformed body is heated and melted to form a fiber reinforced thermoplastic resin sheet. In this preform, since the reinforcing fibers are impregnated with the thermoplastic resin in advance, the high pressure for impregnating the reinforcing fibers with the thermoplastic resin is not necessary. This is because the pressure required for forming the sheet is sufficient to exhaust the air existing between the preforms. That is, the sheet molding can be performed very easily only by melting the thermoplastic resin on the surface of the preformed body and welding the preformed bodies to each other. Therefore, it is possible to form a sheet at a much lower pressure than in the conventional case, so that the outflow of the molten resin can be significantly prevented. As a result, there is no concern about contamination of the apparatus (for example, molds and rolls) with the molten resin, and there is no concern about fluctuations in the fiber weight content of the obtained sheet. Thus, according to the production method of the present invention, a fiber-reinforced thermoplastic resin sheet can be obtained with extremely excellent productivity.

Moreover, as described above, in the preform, since the reinforcing fiber is impregnated with the thermoplastic resin in advance,
Despite the low pressure sheet forming, the impregnated state of the resulting sheet is very good (ie void free and excellent wettability between the reinforcing fibers and the thermoplastic resin).

Furthermore, according to the present invention, the preform is heat-melted through the heat-resistant release article having a melting point or a melting point higher than that of the thermoplastic resin to form the fiber-reinforced thermoplastic resin sheet. . In a preferred embodiment, the heat-resistant release article has a box shape or a bag shape, so that the outflow of the molten resin can be significantly prevented.

As described above, according to the present invention, there is provided a fiber-reinforced thermoplastic resin sheet satisfying both the impregnating property and the productivity. Moreover, since the manufacturing method of the present invention does not require any expensive device or equipment at all, it is possible to manufacture the fiber-reinforced thermoplastic resin sheet at an extremely low cost.

[0053]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 75 parts by weight of glass fiber as a reinforcing fiber and polypropylene 2 as a thermoplastic resin were added.
After impregnating 5 parts by weight, width 10 mm, thickness 0.1 mm
It was cut into a tape shape. Plain weave this tape-like material 1
Three sheets were laminated to obtain a preform. A Teflon glass sheet having a thickness of 0.1 mm was placed as a heat-resistant release article on the upper surface and the lower surface of this preform. In this way, a preform in which the heat-resistant release article was placed was obtained.

On the other hand, a mold having a side of 450 mm is attached to each heating plate of a press device having two heating plates (that is, presses) whose temperature can be adjusted, and a first press mold and a second press mold are attached. It was a mold. The first press die is 2
The second press die was heated to 20 ° C and 100 ° C. First
A preform having a heat-resistant release article placed thereon was placed in a press die, and heated and melted at a pressure of 3 kgf / cm ² for 3 minutes. The melted preform was conveyed to a second press die, and cooled and solidified for 1 minute at a pressure of 20 kgf / cm ² using the second press die to obtain a fiber-reinforced thermoplastic resin sheet having a thickness of 2 mm.

The time required from the placement of the preform in the first press die to the taking out of the obtained fiber-reinforced thermoplastic resin sheet was 4 minutes and 45 seconds, which is more than that of the conventional forming method. The time required was significantly shortened.

When the contamination state of the die was examined, almost no contamination due to the outflow of the thermoplastic resin was observed in both the first press die and the second press die.

The peeling of the Teflon glass sheet from the obtained sheet was extremely easy.

Further, by observing the cross section of the obtained sheet, it was found that no void was observed and a sheet having an excellent impregnation state was obtained.

(Example 2) A tape-like material produced in the same manner as in Example 1 was cut to a length of 20 mm to obtain a thin film piece.

On the other hand, as a heat-resistant release article, an aluminum foil surface-treated with a commercially available release agent (thickness 0.1 mm)
Was processed into a box shape having a side of 450 mm and a depth of 30 mm.
After 1.1 kg of the thin film pieces were deposited in the box-shaped product to form a preform, the top of the box was covered with an aluminum foil (thickness 0.1 mm) surface-treated with a commercially available release agent. In this way, a preform in which the heat-resistant release article was placed was obtained.

The following procedure was carried out in the same manner as in Example 1 to obtain a fiber reinforced thermoplastic resin sheet.

The time required from the placement of the preform in the first press die to the taking out of the obtained fiber reinforced thermoplastic resin sheet was 4 minutes and 45 seconds, which is more than that of the conventional forming method. The time required was significantly shortened.

When the contamination state of the mold was examined, almost no contamination due to the outflow of the thermoplastic resin was observed in both the first press mold and the second press mold.

The peeling of the aluminum foil from the obtained sheet was carried out by
It was very easy.

Further, by observing the cross section of the obtained sheet, it was found that no void was observed and a sheet having an excellent impregnation state was obtained.

Example 3 Instead of covering the upper part of the box on which the preform was deposited with an aluminum foil surface-treated with a commercially available release agent, a box-like shape machined from an aluminum foil surface-treated with a commercially available release agent was used. A fiber-reinforced thermoplastic resin sheet was obtained in the same manner as in Example 2 except that the fiber-reinforced thermoplastic resin sheet was covered.

The time required from the placement of the preform in the first press die to the taking out of the obtained fiber reinforced thermoplastic resin sheet was 4 minutes and 45 seconds, which is more than that of the conventional forming method. The time required was significantly shortened.

When the contamination state of the die was examined, almost no contamination due to the outflow of the thermoplastic resin was observed in both the first press die and the second press die.

The peeling of the aluminum foil from the obtained sheet was
It was very easy.

Further, by observing the cross section of the obtained sheet, it was found that no void was observed and a sheet having an excellent impregnation state was obtained.

(Example 4) Tape-like materials produced in the same manner as in Example 1 were aligned in one direction. Thirteen layers were alternately laminated so that the alignment directions were orthogonal to each other to obtain a preform.

The following procedure was carried out in the same manner as in Example 3 to obtain a fiber reinforced thermoplastic resin sheet.

The time required from the placement of the preform in the first press die to the taking out of the obtained fiber-reinforced thermoplastic resin sheet was 4 minutes and 45 seconds, which is higher than that of the conventional forming method. The time required was significantly shortened.

When the contamination state of the die was examined, almost no contamination due to the outflow of the thermoplastic resin was observed in both the first press die and the second press die.

Peeling of the Teflon glass sheet from the obtained sheet was extremely easy.

Further, by observing the cross section of the obtained sheet, it was found that no void was observed and a sheet having an excellent impregnation state was obtained.

(Comparative Example 1) A mold having a side of 450 mm was attached to a heating plate of a press having a heating plate capable of adjusting temperature, and heated to 220 ° C. for 2 hours. 1.1 kg of a thin film piece prepared in the same manner as in Example 2 was placed in a heated mold, and a pressure of 25 kgf / cm ² was maintained for 10 minutes for melt impregnation. By allowing the mold to cool to 100 ° C. while maintaining the pressure of 25 kgf / cm ² ,
The melt-impregnated thermoplastic resin was cooled and solidified to obtain a fiber-reinforced thermoplastic resin sheet. The time required for cooling was 12 hours and 30 minutes.

The time required from placing the thin film piece on the mold to taking out the obtained fiber-reinforced thermoplastic resin sheet was an extremely long time of 13 hours.

The impregnation state of the obtained resin was good, but when the contamination state of the mold was examined, a large amount of the thermoplastic resin that had flowed out adhered, and it took 15 minutes to remove it. did.

(Comparative Example 2) A mold having a side of 450 mm was attached to a first press of a press device having two heating plates (that is, presses) capable of adjusting temperature, and 220 ° C.
Heated for 2 hours. A thin film piece (1.1 kg) prepared in the same manner as in Example 2 was placed in this mold to obtain 25 kg.
The pressure of f / cm ² was maintained for 10 minutes for melt impregnation.
Next, the mold is conveyed to the second press and 25 kgf /
While maintaining the pressure of cm ² , press the heating plate to about 15 ℃
The mold was cooled to 100 ° C. by flowing the cooling water of the above. In this way, the melt-impregnated thermoplastic resin was cooled and solidified to obtain a fiber-reinforced thermoplastic resin sheet. The time required for cooling was 30 minutes.

The time required from placing the thin film piece on the mold to taking out the obtained fiber reinforced thermoplastic resin sheet was 45 minutes, which was a long time as compared with Examples 1 to 4. .

The impregnation state of the obtained resin was good, but when the contamination state of the mold was examined, a large amount of the thermoplastic resin that had flowed out adhered, and it took 15 minutes to remove it. did.

(Comparative Example 3) A fiber was prepared in the same manner as in Comparative Example 2 except that a laminate produced in the same manner as in Example 1 was used instead of the thin film piece produced in the same manner as in Example 2. A reinforced thermoplastic resin sheet was obtained.

The time required from placing the laminate on the mold to taking out the obtained fiber reinforced thermoplastic resin sheet was 45 minutes, which was about 10 times as long as in Examples 1 to 4. did.

The impregnated state of the obtained resin was good, but when the contamination state of the mold was examined, a large amount of the thermoplastic resin that had flowed out adhered, and it took 10 minutes to remove it. did.

(Comparative Example 4) A fiber-reinforced thermoplastic resin sheet was obtained in the same manner as in Comparative Example 2 except that a laminated body in which 28 layers of glass roving cloth and polypropylene film were alternately laminated.

The time required from the placement of the laminate in the mold to the taking out of the obtained fiber reinforced thermoplastic resin sheet was 45 minutes, which was about 10 times as long as in Examples 1 to 4. did.

When the polluted state of the mold was examined, a large amount of the thermoplastic resin that had flowed out adhered, and it took 20 minutes to remove it.

Furthermore, when the cross section of the obtained sheet was observed, many voids were observed between the glass fibers in the glass roving cloth, and the impregnation state was poor.

(Comparative Example 5) As in Example 1, the width is 1 m.
The plain weave of the above was produced and 13 layers were laminated. Using a double belt press, heating temperature 220 ℃, molding pressure 5kgf /
The laminate was sheet-molded at cm ^{2 at} a molding speed of 0.5 m / min to obtain a fiber-reinforced thermoplastic resin sheet.

Although a fiber-reinforced thermoplastic resin sheet could be obtained, a large amount of molten thermoplastic resin flowed out from the end portion in the width direction of the belt, and the apparatus was significantly polluted. Further, when the cross section of the obtained sheet was observed, many voids were observed and the impregnation state was poor.

(Comparative Example 6) The same procedure as in Comparative Example 5 was repeated except that the thin film piece prepared in the same manner as in Example 2 was used.
Attempts were made to form a fiber-reinforced thermoplastic resin sheet, but the molten thermoplastic resin flowed out significantly from the widthwise end of the belt, and a sheet having a desired thickness could not be obtained. further,
When the cross section of the obtained sheet was observed, many voids were observed and the impregnation state was poor.

[0094]

EFFECTS OF THE INVENTION According to the present invention, the fiber reinforced which satisfies the impregnating property and the productivity at the same time, does not cause the molten resin to flow out, can obtain a desired fiber weight content, and can be implemented at a low cost. A method for manufacturing a thermoplastic resin sheet is provided.

Claims (11)

[Claims] 1. A method for producing a fiber-reinforced thermoplastic resin sheet containing reinforcing fibers and a thermoplastic resin, the method comprising molding a preform containing the reinforcing fibers and the thermoplastic resin, Arranging a heat-resistant release article having a melting point higher than the softening point or melting point of the thermoplastic resin on at least the upper surface and the lower surface of the preform, and under pressure, and the softening point of the aged resin or Melting the preform through the heat-resistant release article at a temperature equal to or higher than the melting point, and under pressure, and at a temperature below the softening point or melting point of the thermoplastic resin, the melted preform A method for producing a fiber-reinforced thermoplastic resin sheet, comprising the step of cooling and solidifying the body. 2. The preform has a length of 5 mm to 100.
mm, width 5 mm to 30 mm, and thickness 0.05 mm to
The deposit according to claim 1, which is a deposit of 0.3 mm thin film pieces, wherein the weight ratio of the reinforcing fiber and the thermoplastic resin contained in the preform is 85/15 to 50/50. A method for producing a fiber-reinforced thermoplastic resin sheet. 3. The preform has a width of 5 mm to 30 mm.
And a laminate of woven fabric formed from a tape-shaped material having a thickness of 0.05 mm to 0.3 mm, wherein the weight ratio of the reinforcing fiber and the thermoplastic resin contained in the preform is 8
The method for producing a fiber-reinforced thermoplastic resin sheet according to claim 1, which is 5/15 to 50/50. 4. The preform is a laminate of unidirectional reinforcing sheets selected from a unidirectional laminate, an orthogonal laminate, an oblique laminate and a combination thereof, and is contained in the preform. The method for producing a fiber-reinforced thermoplastic resin sheet according to claim 1, wherein the weight ratio of the reinforcing fibers and the thermoplastic resin is 85/15 to 50/50. 5. The method for producing a fiber-reinforced thermoplastic resin sheet according to claim 1, wherein the preform is a combination of at least two preforms according to any one of claims 2 to 4. 6. The method for producing a fiber-reinforced thermoplastic resin sheet according to claim 1, wherein the heat-resistant release article has a box shape. 7. The heat-resistant release article has a thickness of 0.05 m.
The method for producing a fiber-reinforced thermoplastic resin sheet according to any one of claims 1 to 6, comprising a metal foil having a thickness of m to 1.0 mm. 8. The fiber-reinforced thermoplastic resin according to claim 1, wherein the heat-resistant release article is a metal foil having a release treatment applied to a surface in contact with the preform. Manufacturing method of seaweed. 9. The method for producing a fiber-reinforced thermoplastic resin sheet according to claim 1, wherein the melting step and the cooling and solidifying step are performed using a pressing device. 10. The melting step and the cooling and solidifying step are performed using a double belt press type device.
A method for producing the fiber-reinforced thermoplastic resin sheet according to claim 1. 11. The fiber-reinforced thermoplastic resin sheet according to claim 1, wherein the melting step and the cooling and solidifying step are performed using an apparatus having a heating roll and a cooling roll. Production method.