JPH1067051A - Continuous production of fiber-reinforced thermoplastic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable continuous production of a fiber-reinforced thermoplastic resin foam satisfactorily useful in the field of building materials and light in weight and having high strength-weight and stiffness-weight ratios and a heteromorphic cross-section and also to enable obtaining variously shaped fiber-reinforced thermoplastic resin foams by changing only a portion of a draw mold that has a complicated cross-sectional shape. SOLUTION: A composite sheet A having a fiber-reinforced thermoplastic resin layer A1 and a thermoplastic resin foam layer (2 to 30 ×foam magnification) A2 is continuously shaped such that the fiber-reinforced thermoplastic resin layer A1 makes an external surface and into a hollow body 15 having a simple cross-sectional shape. The hollow body 15 is introduced into a draw mold 6 whose cross-section changes from simple to complicated as the cross-sectional area decreases. The hollow body 15 is heated to a temperature equal to or higher than the softening temperature of the thermoplastic resin, and a certain air pressure is applied to the interior of the hollow body 15, so that the cross-sectional shape thereof is changed until a foam fills the interior space 12 of the hollow body 15 while the outer circumferential surface of the hollow body 15 is pressed against the inner wall of the draw mold 6, whereby draw molding is effected such that a desired heteromorphic cross-sectional shape is imparted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced thermoplastic resin foam comprising a core layer composed of a thermoplastic resin foam and a skin layer composed of a fiber-reinforced thermoplastic resin sheet. About. In other words, the present invention relates to a method for producing a fiber-reinforced thermoplastic resin foam by blow molding a foamed laminated prepreg hollow body.

[0002]

2. Description of the Related Art In recent years, fiber-reinforced resin foams having an irregular cross-sectional shape have been widely used in interior and exterior building materials and other fields.

[0003] As a method for continuously producing a long resin foam having such an irregular cross-sectional shape, for example, Japanese Patent Publication No. 47-11907 discloses a method in which a foamable resin composition is formed into a pipe or cavity through a die. Extrusion into the body and foaming at the same time, then, while the resin is still in a plastic state, by passing through a vacuum sizing mold, it is deformed into a shape different from the extruded shape, and this vacuum sizing mold is replaced By doing so, there has been proposed a method of forming foams having various irregular shapes.

[0004]

However, according to the above-mentioned conventional method for producing a foam having an irregular cross-sectional shape, in order to impart a desired cross-sectional shape and surface smoothness, the material to be molded must be formed using a sizing mold. It is necessary to adhere to the inner surface,
At that time, a large frictional resistance is generated between the contact surface of the sizing mold and the material to be molded, and accordingly, the fiber-reinforced resin foam requires a corresponding tensile strength.

For this reason, conventionally, the extruded resin foam was quenched by a sizing mold to impart tensile strength. However, this involves comprehensively controlling the molding conditions and the cross-sectional shape of the sizing mold. It is necessary to mold while maintaining a balance, and if it is a simple shape, it is also possible to perform a molding operation while maintaining such a balance. In the case of manufacturing a resin foam having a more complicated cross-sectional shape in which the frictional resistance is partially different, it is extremely difficult to manufacture a resin foam having a complicated cross-sectional shape simply by changing only the sizing mold. There was a problem that it was difficult.

Further, according to the conventional method, when a foam having a high expansion ratio is to be produced, sufficient tensile strength cannot be obtained even if the foam is rapidly cooled and solidified. Problems such as stretching in the longitudinal direction or breakage during molding occur, and it is difficult to obtain a foam having a high expansion ratio.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to easily produce a fiber-reinforced resin foam having a high expansion ratio, and to impart a high strength to the fiber-reinforced resin foam. It is possible to continuously produce fiber-reinforced thermoplastic resin foams having a light weight, high specific strength, high specific rigidity, and a desired irregular cross-sectional shape, which can be sufficiently used in the field of building materials. It is an object of the present invention to provide a method capable of obtaining fiber reinforced resin foams of various shapes by changing only the above.

[0008]

In order to achieve the above-mentioned object, a method for continuously producing a fiber-reinforced thermoplastic resin foam according to the present invention comprises a fiber and a thermoplastic resin comprising a large number of continuous monofilaments aligned in a longitudinal direction. A composite sheet having a fiber-reinforced thermoplastic resin layer in which the resin is integrated, and a thermoplastic resin foam layer having an expansion ratio of 2 to 30 times, such that the fiber-reinforced thermoplastic resin layer becomes the outer surface. ,
And a step of continuously shaping into one hollow body having a simple cross-sectional shape, and reducing the cross-sectional area of the hollow body from a simple cross-sectional shape to a more complicated cross-sectional shape. Introduced into the changing drawing mold, the hollow body is heated above the softening temperature of the thermoplastic resin inside the mold, and air pressure is applied to the inside of the hollow body, and the outer peripheral surface of the hollow body softened by heating While pressing against the inner wall of the drawing die, changing the cross-sectional shape until the internal space of the hollow body is filled with the foam, shaping into a desired cross-sectional shape, and performing a drawing process. It is assumed that.

[0009] The "pull-drawing molding method" generally refers to a molding method using a thermosetting resin. However, since the method is common in that a reinforcing fiber is guided to a shaping mold and pulled out, a method using a thermoplastic resin is used. It shall be used also in the invention.

In the above, first, the fiber reinforced thermoplastic resin layer will be described.

In the present invention, the type of the thermoplastic resin used in the fiber-reinforced thermoplastic resin layer is not particularly limited, and examples thereof include polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene, and polyamide. , Polycarbonate, polyphenylene sulfide, polysulfone, polyether sulfone, polyphenylene oxide, polyvinylidene fluoride, polyether ether ketone, polymethyl methacrylate, and thermoplastic elastomer.

Further, a copolymer or a graft resin containing the above-mentioned thermoplastic resin as a main component, for example, ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, silane-modified polyethylene, acrylic acid-modified polypropylene and the like are used. You can also.

The above thermoplastic resin can be used alone or
It may be used in combination, that is, as a polymer alloy, and other additives such as a heat stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a pigment, a reinforcing short fiber, and the like for a thermoplastic resin. Materials, processing aids, modifiers and the like may be added.

Thermoplastic resin in fiber-reinforced thermoplastic resin layer
Fat Conditions In the present invention, the heat-resistant resin used for the fiber-reinforced thermoplastic resin layer is used.
1 × 10 plastic resin ^Five~ 1 × 10⁷High poise melting
Preferably, it has viscosity. Such high
By using a thermoplastic resin of viscosity, the inside of the drawing mold
Thickness change of fiber reinforced thermoplastic resin layer
Fiber reinforced heat with excellent moldability.
A plastic resin sheet is obtained.

Here, the melt viscosity of the thermoplastic resin is 1 × 1
0 is less than ⁵ poise, the pressure of the foamed resin, thickness unevenness occurs in the fiber-reinforced resin layer, also exceeds 1 × 10 ⁷ poises, the formability becomes poor, the molded body can be molded with a simple cross-sectional shape However, it is difficult to shape a molded article having a complicated cross-sectional shape by the pressure of the foamed resin.

Further, in the drawing die, the fiber-reinforced thermoplastic resin layer may be stretched. In such a case, it is preferable to use a thermoplastic resin having high stretchability to improve the stretchability. For this purpose, the resin may be subjected to a crosslinking treatment.

Further, when applying an internal air pressure to the inside of the hollow body in the drawing die, the fiber-reinforced thermoplastic resin layer is required to be airtight. This airtightness depends on the volume ratio of the reinforcing fibers in the fiber-reinforced thermoplastic resin layer, the adhesion between the reinforcing fibers and the thermoplastic resin, the cross-sectional change, the degree of elongation change, but in some cases, In order to impart airtightness, a layer of only a thermoplastic resin having high stretchability and airtightness may be separately provided in the fiber reinforced thermoplastic resin layer.

In the present invention, the fibers used in the fiber-reinforced thermoplastic resin layer include, for example, inorganic fibers such as glass fibers and carbon fibers,
All fibers usable as reinforcing fibers, such as organic fibers such as silicon fiber, boron fiber, polyester fiber, aramid fiber, and vinylon, metal fibers such as iron and titanium, and natural fibers such as silk, cotton, and hemp are listed. These fibers may be used as a single type of fiber or as a mixture of two or more different types of fibers.

In order to maintain the impact resistance of the fiber-reinforced thermoplastic resin layer and not to impair the surface smoothness, the fiber has a diameter of 1 to 50 μm, particularly 3 to 25 μm, and a length of It is preferable to use long fibers or continuous fibers of 10 mm or more.

In order to obtain a sufficient reinforcing effect and airtightness, it is preferable that a thermoplastic resin is sufficiently impregnated and held between each filament of the above-mentioned fibers. In order to enhance the adhesion between the fiber and the resin, the fiber may be subjected to a surface treatment conventionally applied to the glass fiber or a pretreatment for improving the affinity between the fiber and the resin.

Form of Reinforced Fiber The form of the fiber inside the fiber reinforced thermoplastic resin layer is as follows:
There is no particular limitation as long as there is at least one layer in which the continuous fibers are arranged in the longitudinal direction. For example, a state in which the long fibers are randomly oriented, or a mat shape in which the long fibers are entangled with each other, and the continuous fibers are bundled Strands, cloths in which fibers are woven in two-dimensional and three-dimensional shapes, and those in which each continuous filament is dispersed in a thermoplastic resin and aligned in the longitudinal direction of the sheet. is there.

The fiber-reinforced thermoplastic resin layer may include a laminate in which a plurality of fiber layers of these forms are stacked.

Conditions for the fiber-reinforced thermoplastic resin layer In addition to the above conditions, the thickness of the fiber-reinforced thermoplastic resin layer forming the outer surface layer (skin layer) is 0.1 to 5 m.
m is preferred. Here, if the thickness of the fiber-reinforced thermoplastic resin layer is thinner than 0.1 mm, there is no reinforcing effect,
On the other hand, if the thickness exceeds 5 mm, shaping becomes difficult, which is not preferable.

The fiber content in the fiber reinforced thermoplastic resin layer is 5 to 5.
Preferably, it is 70% by volume. Here, if the amount of fibers in the fiber-reinforced thermoplastic resin layer is less than 5% by volume, there is no sufficient reinforcing effect, and molding stability cannot be obtained. It is not preferable because the fiber cannot be impregnated with the plastic resin and fusion becomes difficult, and the reinforcing effect and airtightness are reduced.

Further, since the fiber-reinforced thermoplastic resin layer bears almost all of the shear resistance generated during molding, both the tensile strength and the tensile elastic modulus in the longitudinal direction in the molding temperature range are equal to the above-mentioned shear resistance. It needs to be designed to correspond to the level of resistance. As described in the examples below, the fiber reinforcing layer has a tensile strength of 5%.
It is preferable to have a level of 0 MPa or more and a tensile modulus of elasticity of 5 GPa or more. If the fiber reinforcing layer is at such a level, the fiber-reinforced thermoplastic resin layer is not distorted in the longitudinal direction during molding and breaks. Without the need to perform, stable moldability can be obtained.

Manufacturing method of fiber-reinforced thermoplastic resin layer The fiber-reinforced thermoplastic resin used in the present invention is not particularly limited, but is manufactured, for example, as follows.

First, in the case of producing a fiber-reinforced thermoplastic resin having a fiber form arranged in one direction, the powdery thermoplastic resin is placed in a fluidized tank and provided at the bottom of the tank. By jetting air from the perforated plate to a fluidized state, a plurality of fiber bundles guided by guide rolls are passed therethrough to form a thermoplastic resin-attached fiber bundle, and thereafter, by passing through a heating roll, the fiber Is melt impregnated with a thermoplastic resin, and further passed through a cooling roll to obtain a desired fiber-reinforced thermoplastic resin.

When producing a fiber-reinforced thermoplastic resin in which fibers are randomly arranged, the thermoplastic resin-adhered fiber bundle obtained as described above is cut into small pieces by a rotary cutter and Drop it onto the endless belt, accumulate it, press it while sandwiching it with the upper and lower endless belts, pass through the heating furnace, melt impregnate the chopped fibers with the thermoplastic resin, and further pass through the cooling roll, Obtain the desired fiber reinforced thermoplastic resin.

When a resin having a low melt viscosity is used, the fiber reinforced thermoplastic resin can be obtained by directly infiltrating the thermoplastic resin in a molten state into the fiber base material. At this time, it is necessary that the thermoplastic resin does not flow under its own weight at the time of melting after being compounded. Therefore, after complexing, it is necessary to increase the melt viscosity by polymerizing or modifying the thermoplastic resin by a crosslinking treatment or the like.

Next, the thermoplastic resin foam layer will be described.

Conditions for the thermoplastic resin used for the thermoplastic resin foam layer As the thermoplastic resin used for the foam layer, basically any thermoplastic resin can be used as long as it can be continuously molded as a foam. It is, however, that the thermoplastic resin used for the fiber-reinforced thermoplastic resin layer and the one having heat-fusibility,
preferable.

However, as long as they can be joined to each other via the adhesive layer, a resin having no heat-fusing property with respect to the thermoplastic resin on the fiber reinforced resin layer side can be used, and heating and cooling in the molding process can be used. There is no problem if the fiber-reinforced thermoplastic resin layer and the foam layer do not easily peel off after solidification.

The thermoplastic resin used for the foam layer is as follows:
In the molding temperature range, it is preferable that the resin be in a plasticized state together with the fiber-reinforced thermoplastic resin layer, and have a lower viscosity and flow more easily than the thermoplastic resin on the fiber-reinforced thermoplastic resin layer side. The thermoplastic resin foam itself may be hard or soft, depending on the product use.

The conditions of the thermoplastic resin foam layer The expansion ratio of the thermoplastic resin foam constituting the foam layer is as follows:
It is preferably 2 to 30 times, and more preferably 5 to 15 times.

Here, when the expansion ratio of the thermoplastic resin foam is less than 2 times, even if the cross-sectional shape of the hollow body is changed during the molding inside the drawing die, the internal space of the hollow body is not expanded. And the expansion ratio is 30
Exceeding the number of times is undesirable because heating at the time of molding breaks the foamed cells and generates pores, making it impossible to maintain airtightness. The closed cell rate of the thermoplastic resin foam is preferably 60% or more. If the closed cell rate is less than 60%, it is difficult to maintain airtightness stably.

The thickness of the thermoplastic resin foam layer depends on the final shape of the molded product, but is preferably about 2 to 10 mm. More preferably, it is 3 to 6 mm.

If the thickness of the foam layer is less than 2 mm, it is difficult to form a molded article having a complicated cross-sectional shape, and if it exceeds 10 mm, it is difficult to uniformly heat the inside of the foam. It is not preferable because it becomes difficult to stably shape the composite sheet into a hollow body.

Next, the composite sheet will be described.

The method for producing the composite sheet The method for producing the composite sheet is not particularly limited. For example, a fiber-reinforced thermoplastic resin sheet previously produced by the above-mentioned method may be added to a thermoplastic resin foam sheet produced separately in advance. To obtain a composite sheet by heating and fusing, or a method of obtaining a composite sheet by bonding and integrating the above fiber-reinforced thermoplastic resin sheet and a thermoplastic resin foam sheet through an adhesive layer. And the like.

Method for Forming a Composite Sheet into a Hollow Body The method for forming a composite sheet is not particularly limited. For example, in addition to a method using a mold described in Examples described later, a synthetic resin shoe or roll may be used. Etc., and gradually bending the composite sheet to form a hollow body. When shaping the composite sheet into a hollow body, the shaping is performed by heating with a far-infrared heater or a hot air blower so that the thermoplastic resin is in a softened state.

In the present invention, the term "hollow body" refers to a composite sheet formed by abutting or superimposing the left and right side edges of the composite sheet to form a hollow shape. The case where a portion without a plastic resin foam layer is provided and the fiber-reinforced thermoplastic resin layer on the side edge of the composite sheet is overlapped with the other side edge of the composite sheet to form a hollow shape is also included. It is.

Further, a plurality of composite sheets may be used and shaped in the same manner as described above.

Next, a method of applying air pressure to the inside of the hollow body in the drawing die will be described.

In order to apply air pressure to the inside of the hollow body, for example, a general supply method of injecting air into the inside of the hollow body through an air hole inside the core member provided at the rear of the drawing die can be applied. However, it is necessary to provide a constant pressure holding mechanism capable of holding the internal space of the hollow body at a constant pressure.

Here, the applied air pressure depends on the sectional shape of the hollow body, but is preferably in the range of 0.5 to 5 kg / cm ² . When the air pressure is less than 0.5 kg / cm ² , the cross-sectional shape changes until the foam fills the internal space of the hollow body while pressing the outer peripheral surface of the hollow body softened by heating against the inner wall of the drawing die. As a result, it is difficult to stably mold to form a desired cross-sectional shape, and a stable contour cannot be formed, which is not preferable. If the air pressure exceeds 5 kg / cm ² , the pressure is too high to maintain the airtightness inside the hollow body, or the thermoplastic resin foam layer is compressed by the air pressure, resulting in a foam having a high expansion ratio. It is not preferable because it becomes difficult to produce a molded article having a layer.

[0046]

Next, an embodiment of the present invention will be described.
This will be described with reference to the drawings.

In this specification, the front, rear, left and right refer to FIG. 1, the front refers to the right side of FIG. 1, the rear refers to the same left side, and the left and right refer to the front.

First, as shown in FIG. 1, a fiber composed of a large number of continuous monofilaments aligned in the longitudinal direction and a thermoplastic resin are integrated and have a tensile strength of 50M.
A high-strength fiber-reinforced thermoplastic resin layer (A1) having Pa or more and a tensile modulus of 5 GPa or more, and an expansion ratio of 2 to 30;
Composite sheet with double thermoplastic resin foam layer (A2)
Use (A). The composite sheet (A) is continuously drawn while being shaped so that the fiber-reinforced thermoplastic resin layer (A1) is on the outer surface and has a simple hollow shape such as a circular cross section or a rectangular cross section. Introduce to type (6).

The drawing die (6) is changed from a simple shape as shown in FIG. 2 to a complex deformed shape as shown in FIG. 4 so that the cross section changes smoothly while reducing its cross-sectional area. It is composed of separate simple shape portions (61) and complicated shape portions (62).

As described above, if the simple shape portion (61) and the complicated shape portion (62) of the drawing die (6) are separated from each other, only the latter is replaced, so that various shapes of the foamed molded body can be obtained. Although (11) can be obtained, both may be integrated.

Accordingly, an internal space (12) is formed by the drawing core (1) on the inlet side and the thermoplastic resin foam layer (A2) inside the composite sheet (A) shown in FIG. Is done.

In the mold (61), the hollow body (15) is heated to a temperature higher than the softening temperature of the thermoplastic resin to bring the whole into a plastic state and communicate with the inside of the mold core (1). Air is injected into the internal space (12) of the hollow body (15) through the air holes (2) and (3) provided in the, and air pressure is applied to the inside of the hollow body (15). By this air pressure, the surface of the fiber-reinforced thermoplastic resin layer (A1) on the outer peripheral surface of the softened hollow body (15) is brought into close contact with the inner wall of the drawing die (6). Thus, the hollow body (1) softened by air pressure
5) By pulling out the outer surface while pressing it against the inner wall of the drawing die (6), the hollow body (15) having a simple cross-sectional shape changes smoothly in cross-section to obtain a desired complicated cross-sectional irregular shape. It is to be molded.

At this time, since the entire composite sheet (A) is heated to a plastic state, and the thermoplastic resin foam layer (A2) itself is also in a plastic state, it is compressed in the thickness direction by air pressure. It becomes possible.

Therefore, when introducing into the drawing die (6),
As shown in FIG. 2, the thermoplastic resin foam layer (A2) is compressed at the inlet formed by the mold core (1) and the drawing mold (61) to ensure airtightness, As shown in FIG. 3, an inner peripheral surface of the hollow body (15) is formed in an intermediate portion where the hollow body (15) having a cross-sectional shape smoothly changes in cross-section and is formed into a complicated cross-sectional shape. Is a thermoplastic resin foam layer (A
At the time when the airtightness is ensured and the final shape is formed by being surrounded by 2), as shown in FIG. 4, the thermoplastic resin foam layer (A2) is formed inside the hollow body (15). By filling the space (12), airtightness can be secured,
An arbitrary air pressure can be applied to the internal space (12).

As described above, when introducing into the drawing die (6),
And at the stage of shaping into a desired shape, the composite sheet
The thermoplastic resin foam layer (A2) of (A) serves as a seal layer for providing airtightness, and is required in the internal space (12) of the hollow body (15) inside the drawing die (6). Air pressure can be applied. By applying air pressure to the internal space (12) of the hollow body (15) in this manner, the fiber-reinforced thermoplastic resin layer (A1) can always be attached to the inner wall surface of the drawing mold (62), which is complicated. It is possible to stably and smoothly change the cross-section into an irregularly shaped shape.

In the step of changing the cross section of the hollow body (15), considerable shear resistance is generated.
Since the fiber-reinforced thermoplastic resin layer (A1) of (A) has strength enough to withstand this shear resistance, the thermoplastic resin foam layer (A2) does not break, etc. (A)
Thus, the fiber-reinforced thermoplastic resin foam (11) can be molded while maintaining the properties described above, and it is impossible to form the fiber with the above-mentioned conventional technology.

By changing the drawing die (62), the cooling die (9) and, if necessary, the heat insulating material (7), foamed molded products (11) of various shapes can be obtained. .

[0058]

Next, an embodiment of the present invention will be described with reference to the drawings.
Description will be given together with a comparative example.

Example First, a composite sheet (A) having a fiber-reinforced thermoplastic resin layer (A1) and a thermoplastic resin foam layer (A2) shown in FIG. 1 was produced by the following method.

As the thermoplastic resin composition used for the fiber-reinforced thermoplastic resin layer (A1), a powdery polypropylene resin composition having an average particle diameter of 100 μm and a melt viscosity of 2.4 × 10 ⁵ poise is used. did.

As shown in FIG. 5, a glass roving fiber bundle (4400 tex) composed of filaments having a diameter of about 23 μm (4400 tex) (22) (24) is fed out from a roving feeder (21). It was arranged in upper and lower two tiers.

On the other hand, polyvinyl chloride (melt viscosity 2.4 × 10 ⁵ poise) 100 was placed in the tanks 23 and 23 arranged vertically.
Parts by weight, 2 parts by weight of a tin-based heat stabilizer, and 0.5 parts by weight of polyethylene wax, and has an average particle size of 10
A predetermined amount of each of the powdery resin compositions (24) and (24) having a thickness of 0 μm is charged, and air is blown out through a perforated plate provided at the bottom of the tanks (23) and (23), whereby the powdery resin ) (24) was fluidized to form a fluidized bed.

Then, the two upper and lower glass fiber bundles (22) and (22) guided by guide rolls are passed through the fluidized beds in the upper and lower tanks (23) and (23), respectively.
The powdery resin (24) was attached to the filament of each glass fiber bundle (22).

Next, the glass fiber bundles (22) and (22) to which the powdery resins (24) and (24) are adhered are guided from the upper and lower two systems and stacked by a pair of upper and lower guide rolls (25) and (25). At the same time, these resin-attached glass fiber bundles (22)
Heating by passing through a heating furnace (24) heated to
Pressing, melting the powdery resin composition (24) (24), impregnating between the filaments of the glass fiber bundle (22) (22) to form a sheet, and then, the sheet is a pair of upper and lower cooling rolls (27)
After cooling by (27), a fiber-reinforced thermoplastic resin sheet (A1) having a thickness of 1.2 mm and a predetermined width was obtained, and was wound by a winder (28). The glass fiber content in the fiber reinforced thermoplastic resin sheet (A1) was 30% by volume.

On the other hand, the thermoplastic resin composition used in the thermoplastic resin foam layer (A2) includes 100 parts by weight of high-density polyethylene, 100 parts by weight of homopropylene, 40 parts by weight of silane-crosslinkable polypropylene, and azodicarbonate. It was produced as follows using a resin composition composed of 2 parts by weight of amide.

That is, this resin composition was melt-kneaded at 180 ° C. using a twin-screw extruder (not shown) to form a sheet. Next, this resin composition sheet is immersed in hot water at 100 ° C. for 1 hour, dried, and further continuously supplied to a heating furnace at 220 ° C. to foam the resin composition sheet. A thermoplastic resin foam sheet (A2) having a thickness of 4 mm and an expansion ratio of 10 was obtained.

At the same time as the molding of the thermoplastic resin foam sheet (A2), the fiber reinforced thermoplastic resin sheet (A1) is laminated on the resin foam sheet (A2) to obtain a width 3 mm.
A composite sheet (A) having a thickness of 00 mm and a thickness of 5 mm was produced.

The composite sheet (A) is provided with only a 5 mm wide fiber reinforced thermoplastic resin layer (A1) having no thermoplastic resin foam layer (A2) on one side edge thereof. It is.

Next, the composite sheet (A) produced as described above is supplied to the production apparatus shown in FIG. 1, and the fiber-reinforced thermoplastic resin foam (11) is continuously produced by the method of the present invention. Manufactured.

That is, the manufacturing apparatus shown in FIG. 1 comprises a rewind roll (not shown) around which the composite sheet (A) is wound,
A guide member (not shown), which is disposed in front of the drawing direction and is capable of gradually forming the composite sheet (A) into a circular cross section, and an inner surface of a hollow body (15) made of the composite sheet (A) The mold core (1), which can regulate the shape, and the sectional shape is gradually and gradually changed as shown in FIG. 2, FIG. 3, and FIG. (62), a heating heater (13) provided on the outer periphery of the drawing die (6), and a die shown in FIG.
(6) A heat insulating material (7) having the same cross-sectional shape as the cross section, a cooling mold (9) arranged following the heat insulating material (7) and having a large number of water passage holes (8), and drawing out And a take-up machine (10) arranged forward in the direction.

A heater (14) for heating the composite sheet (A) gradually into a circular shape is arranged on the upper portion near the entrance of the drawing die (6). At the lower end of the drawing die (6) on the entrance side, a heating pinch roll for overlapping and joining the side edges of the composite sheet (A)
(4) and a heater (5) below the heater are arranged.

In FIG. 1, the composite sheet (A) is rewound from a rewinding roll (not shown) and introduced into a drawing die (6). At this time, the composite sheet (A) is The composite sheet (A) is heated to about 60 ° C from above by a heating device (14) near the entrance of the drawing die (6) to soften the fiber-reinforced thermoplastic resin layer (A1) so that it is outside. Let it.

Subsequently, the composite sheet (A) is gradually shaped into a circular cross section by a guide member and introduced into a drawing die (6). At this time, one side edge of the composite sheet (A) is formed. The portion of only the 5 mm wide fiber reinforced thermoplastic resin layer (A1) without the thermoplastic resin foam layer (A2) provided in, is introduced while overlapping the other side edge of the same composite sheet (A), As shown in FIGS. 1 and 2, the overlapped portion is heated by a pinch roll.
(4) was fused and integrated to form a single hollow body (15) having a simple circular cross section.

The drawing die (6) is moved by the external heater (13) to 1
The temperature is adjusted to 60 ° C., and the hollow body (15) is heated inside the mold (6) to a temperature higher than the softening temperature of the thermoplastic resin to bring the whole into a plastic state, and the mold core (1) is heated. ) Is pressed into the internal space (12) of the hollow body (15) through the air holes (2) and (3) provided in communication with the inside of the hollow body (15).
An air pressure of kg / cm ² was applied.

The air pressure causes the softened hollow body (1)
5) A die for drawing the outer surface of the fiber reinforced thermoplastic resin layer (A1)
(6) Close contact with the inner wall. In this way, the hollow body (15) in the softened state is pressed by air pressure and continuously drawn while being pressed against the inner wall of the drawing die (6), whereby the hollow body having a simple circular cross section shown in FIG. 15), as shown in FIG. 3, the cross section was changed smoothly and gradually, and as shown in FIG. 4, it was formed into a desired complicated cross-sectional irregular shape and was shaped.

After shaping, the molded body is guided through a heat insulating material (7) to a cooling mold (9) to be cooled and solidified, and is taken up by a take-up machine (10) to obtain a fiber having a sectional shape shown in FIG. A reinforced thermoplastic resin foam (11) was obtained.

The fiber-reinforced thermoplastic resin foam (1
1) has a thickness of about 7 mm, a thickness of the fiber-reinforced thermoplastic resin layer (A1) of 1.5 mm, and a thickness of the thermoplastic resin foam layer (A2) of about 4 mm. Magnification is about 5 times, and this fiber reinforced thermoplastic resin foam (11) is
/ Min molding speed.

As described above, according to the embodiment of the present invention, even if the fiber-reinforced thermoplastic resin foam (11) has a high expansion ratio, it can be easily manufactured, and the fiber-reinforced thermoplastic resin foam can be easily manufactured. A fiber-reinforced thermoplastic resin that can impart high strength to the plastic resin foam (11) and can be sufficiently used in the field of building materials, etc., is lightweight, has high specific strength and high specific rigidity, and has a desired cross-sectional irregular shape. The foam (11) could be manufactured continuously.

Further, by changing only the drawing die, foamed molded articles (11) having various shapes could be obtained.

Comparative Example For comparison, only the thermoplastic resin foam sheet (A2) was used without using the composite sheet (A) of the above example.
The procedure was performed in the same manner as in the example, except that molding was performed using the same drawing die (6) as in the above-described example.

As a result, the heating temperature of the drawing die (6) was 90
If the temperature exceeds ℃, the thermoplastic resin foam sheet (A2)
(6) It could not withstand the shear resistance with the inner wall surface and was broken. However, below this temperature, the thermoplastic resin foam sheet (A2) could not be formed into a cross-sectional shape as shown in FIG.

[0082]

According to the method for continuously producing a fiber-reinforced thermoplastic resin foam according to the present invention, as described above, a fiber comprising a large number of continuous monofilaments aligned in the longitudinal direction and a thermoplastic resin are integrated. A fiber-reinforced thermoplastic resin layer, and a composite sheet having a thermoplastic resin foam layer having an expansion ratio of 2 to 30 times, such that the fiber-reinforced thermoplastic resin layer is on the outer surface, and a simple cross-sectional shape A step of continuously shaping into one hollow body having the same, and drawing the hollow body from a simple cross-sectional shape to a more complicated cross-sectional shape while reducing its cross-sectional area while reducing the cross-sectional area. Introduce and heat the hollow body inside the mold above the softening temperature of the thermoplastic resin, apply air pressure inside the hollow body, and heat the hollow body outer peripheral surface softened by heating to the drawing mold inner wall. While pressing Forming a desired cross-sectional shape by changing the cross-sectional shape until the foam fills the internal space of the shaped body, and performing pultruding. According to the method of the present invention, a high expansion ratio is obtained. Can be easily manufactured even with a fiber-reinforced thermoplastic resin foam having a high strength, and can impart high strength to the fiber-reinforced thermoplastic resin foam, and can be sufficiently used in the field of building materials and the like. A possible, lightweight, high-strength, high-specific-rigidity, fiber-reinforced thermoplastic resin foam having a desired complex cross-section irregular shape can be continuously produced with good productivity, and therefore, the production cost is low. It has the effect that it can be done.

Further, as compared with the prior art, by changing only the drawing die, there is an effect that foamed molded articles having various shapes can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing the entire apparatus for performing the method of the present invention.

FIG. 2 is an enlarged sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged sectional view taken along the line BB of FIG. 1;

FIG. 4 is an enlarged sectional view taken along line CC of FIG. 1;

FIG. 5 is a schematic side view showing the entire apparatus for manufacturing a fiber-reinforced thermoplastic resin layer used in Example 1.

[Explanation of symbols]

 A Composite Sheet A1 Fiber Reinforced Thermoplastic Resin Layer A2 Thermoplastic Resin Foam Layer 1 Mold Core 2 Air Hole 3 Air Hole 4 Heating Roller 5 Heater 6 Pulling Die 61 Simple Shape of Pulling Die 62 Pulling Die Complex shape part 9 Cooling mold 10 Take-off machine 11 Fiber reinforced thermoplastic resin foam 12 Internal space 13 Outer peripheral heater 14 Heater 15 Hollow body

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B29K 105: 08 B29L 31:10

Claims (1)

[Claims] 1. A fiber reinforced thermoplastic resin layer in which a fiber and a thermoplastic resin composed of a large number of continuous monofilaments aligned in a longitudinal direction are integrated, and a thermoplastic resin foam having an expansion ratio of 2 to 30 times. Continuously forming a composite sheet having a body layer into one hollow body having a simple cross-sectional shape such that the fiber-reinforced thermoplastic resin layer is on the outer surface; and From a simple cross-sectional shape to a more complex cross-sectional shape, is introduced into a drawing die that changes while reducing its cross-sectional area, and the hollow body inside the die is heated above the softening temperature of the thermoplastic resin. While heating, apply air pressure to the inside of the hollow body, while pressing the outer peripheral surface of the hollow body softened by heating against the inner wall of the drawing die, change the cross-sectional shape until the foam fills the internal space of the hollow body By desired Forming a fiber-reinforced thermoplastic resin foam into a cross-sectional shape and drawing.