JP2001192466A - Fiber-reinforced thermoplastic resin structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced thermoplastic resin structure which comprises a thermoplastic resin and reinforcing fibers homogeneously dispersed in the thermoplastic resin and has a specific fiber length distribution and a specified fiber length. SOLUTION: This fiber-reinforced thermoplastic resin structure comprising a thermoplastic resin and reinforcing fibers, characterized in that the ratio of the weight-average fiber length of the homogeneously dispersed reinforcing fibers to their number-average fiber length is 1.1 to 3 and in that the weight- average fiber length is 2 to 15 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced thermoplastic resin structure in which the degree of fiber opening and fiber length of reinforcing fibers are controlled, and which is excellent in moldability, mechanical properties and surface smoothness. More specifically, a fiber suitable for a cylinder head cover of an automobile, a bumper beam, a seat frame, an instrument panel, a wheel cap, a battery tray, a chassis or a housing of an OA or a home appliance, and a tool housing. The present invention relates to reinforced pellets and injection molded articles, blow molded articles, tubes, pipes and sheets, and even sheets for thermoforming.

[0002]

2. Description of the Related Art Fiber-reinforced thermoplastic structures are used in various applications such as automobile parts and OA equipment, taking advantage of their excellent mechanical properties. In particular, studies are underway to increase the reinforcing fiber length and improve the mechanical properties and the like. For example, in the case of a fiber reinforced thermoplastic pellet structure, Japanese Patent Publication No.
In the method of kneading chopped strands using an extruder as disclosed in Japanese Patent Publication No. 0738, the reinforcing fibers are broken and good mechanical properties are not exhibited.
No. 94 Pultrusion method (pultruding method)
The mainstream is a pellet structure in which a continuous roving of reinforcing fibers is coated with a thermoplastic resin and cut into a predetermined length. Also, as disclosed in JP-A-3-7307, a pellet structure having a fiber length of 3 to 20 mm uniformly dispersed by a papermaking method or a dry nonwoven method is disclosed in JP-A-63-951.
As in JP-A No. 1 (KOKAI), a pellet structure in which resin powder and glass fiber are mixed in advance with a Henschel mixer or the like and then melted with a ram extruder is also known. Also, in the case of a sheet structure for thermoforming, a laminating method of a glass fiber mat as disclosed in JP-B-63-15135 or JP-B-4-4037.
A sheet structure including a discontinuous single fiber of 7 mm to 50 mm by a papermaking method as disclosed in Japanese Patent Publication No. 2 (Kokai) No. 2 is known.

An attempt to control the fiber opening length and fiber length of a reinforcing fiber by an extruder is disclosed in Japanese Patent Application Laid-Open No. Sho 58-56818.
Japanese Patent Application Laid-Open No. Sho 60-2 discloses a method in which glass roving is supplied from a second supply port of a twin-screw extruder to form a single fiber.
No. 21460, reinforced materials,
There is known a method in which a short fiber cut in a kneading apparatus is dispersed in a kneading apparatus as disclosed in JP-A-125110 or a method in which piston movement is used as disclosed in JP-B-4-80810. As an extruder machined with a screw or a cylinder, as disclosed in Japanese Patent Publication No. Sho 62-57491, a screw provided with an opening kneading region having a large number of projections for crushing organic fillers is disclosed in Japanese Patent Publication No. Sho 63-56845. No. 60-893, a screw of a barrier type mixing section which has been processed to crush inorganic additives, etc.
As disclosed in Japanese Patent Application Laid-Open No. 4 (1999) -210, there is known a kneading element composed of a cylinder or screw specially worked to knead a thermoplastic resin.

[0004]

However, in the above-mentioned structure, although the reinforcing fiber length is long, the degree of opening and the kneading action are insufficient, so that the fluidity, mechanical properties and surface smoothness are insufficient. Not only that, but also low productivity. In particular, the pellet structure obtained by the pultrusion method has not only a fixed fiber length but also a poor fiber opening degree, so that the resin and the fiber are separated by press molding, or the flow during injection molding is reduced. There is a problem that sex is bad. In addition, in the case of the papermaking method, although a homogenous molded product dispersed to a single fiber level without fiber breakage can be obtained, since the kneading action at the interface between the resin and the reinforcing fiber is small, the adhesive strength is low and the mechanical properties are poor. There is a point. In addition, although the laminating method of a glass mat has excellent mechanical properties, it has poor fluidity,
There is a problem that the fiber does not flow to the corners and the like. Therefore, there is a demand for a high-productivity fiber-reinforced thermoplastic structure in which the degree of fiber opening and the fiber length of the reinforcing fiber are controlled, and which is excellent in fluidity, mechanical properties and surface smoothness.

[0005] In general, high productivity can be obtained by using an extruder, but Japanese Patent Application Laid-Open Nos.
In the methods disclosed in JP-A-221460, JP-A-4-125110 and JP-B-4-80810, the degree of opening and the fiber length of the reinforcing fibers cannot be sufficiently controlled, and if the kneading action of the screw is strengthened, the fiber length becomes shorter. If the kneading is weakened, the degree of opening is insufficient and the reinforcing fibers become non-uniform. Furthermore, Japanese Patent Publication No. 62-57
No. 491, JP-B-63-56845 and JP-B-60-8934 are designed to simply crush inorganic or organic fillers or to knead a thermoplastic resin. There is a problem that the fiber length cannot be controlled.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method of controlling the degree of fiber opening to uniformly disperse reinforcing fibers, and while maintaining a long weight-average fiber length, by kneading, a specific fiber length distribution. It has been found that the above problems such as fluidity, mechanical properties, and surface smoothness can be solved by using a fiber-reinforced thermoplastic resin structure. That is, the present invention
Including a thermoplastic resin and reinforcing fibers, the ratio of the weight average fiber length to the number average fiber length of the uniformly dispersed reinforcing fibers is 1.1 to 3, and the weight average fiber length is 2 mm to 15 mm, The present invention provides a fiber-reinforced thermoplastic resin structure.

A feature of the present invention is to provide a structure having a specific fiber length distribution by kneading while maintaining a long fiber length, while controlling the degree of fiber opening to uniformly disperse the reinforcing fibers. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The structure of the present invention refers to a blow-molded product, a structure having a rod shape (including a hollow shape such as a tube or a pipe) or a sheet shape, and a fiber-reinforced heat-generating material such as a thermoforming sheet. It refers to a plastic structure, a fiber-reinforced thermoplastic pellet structure that can be used for various moldings such as injection molding and extrusion of an automobile cylinder head cover, and an injection molded product.

The ratio of the weight average fiber length to the number average fiber length of the reinforcing fibers uniformly dispersed in the structure is 1.1 to 3 and the weight average fiber length is 2 mm to 15 mm, more preferably 4.
5 mm to 12 mm. If the weight-average fiber length is less than 2 mm, the effect of improving mechanical properties cannot be obtained, and if it is 15 mm or more, the fibers become entangled, resulting in an uneven structure, which is not preferable. The ratio between the weight average fiber length and the number average fiber length is 1.1 to 3, preferably 1.3 to 2.5, and more preferably 1.3 to 2.1. If it is less than 1.1, the kneading action is small, and good mechanical properties and fluidity cannot be obtained due to insufficient adhesiveness at the interface between the resin and the fiber. If it exceeds 3, long fibers increase and fiber entanglement occurs. This is not desirable because it results in non-uniform flow and a uniform molded product cannot be obtained. The uniform dispersion according to the present invention refers to a state in which the reinforcing fibers and the resin do not separate when the structure is melt-compressed.
It includes up to a state of binding to about this.

The above-mentioned sheet structure for thermoforming has a ratio of the weight average fiber length to the number average fiber length of the uniformly dispersed reinforcing fibers of 1.1 to 3 and the weight average fiber length of 2 mm to 15 m.
m, more preferably a fiber-reinforced thermoplastic resin structure having a fiber length ratio of 1.3 to 2.5 and a fiber length of 4.5 to 12 mm, which is useful for sheet-like stamping and the like.
The reinforcing fibers are oriented almost randomly on the sheet plane,
Depending on the conditions, the ratio in the flow direction is high.

The rod-shaped structure is a rod having an arbitrary cross section such as a round rod or a rectangle having a diameter of about 1 to 8 mm or a hollow rod.

The fiber-reinforced pellet structure of the present invention is a structure obtained by pelletizing the above-mentioned sheet or rod-like structure with a pelletizer or a sheet cutter. When the sheet is pelletized, cutting (cutting) is performed vertically and horizontally. However, since the rod-shaped structure needs to be cut (cut) only in one direction and fiber breakage is small, it is desirable to pelletize the rod-shaped structure. Although the pellet length and the fiber length of the pellet structure are not particularly limited, the pellet length is usually １ ／ of the weight average fiber length of the fiber reinforced thermoplastic resin structure before cutting in order to increase the fiber length. Above all, it is particularly desirable that it is about 15 mm or less. Further, as a feature of the pellet of the present invention, the weight average fiber length in the pellet is shorter than the fiber length of a rod-shaped material or the like, and usually becomes 0.9 or less, sometimes 0.7 or less, of the pellet length.

Further, the pellet structure of the present invention can be used for known molding such as compression molding, injection molding and extrusion molding.
Except for compression molding, injection molding, screw-type molding machines usually used for extrusion molding, since the fiber length and distribution of the reinforcing fiber changes by molding, in the pellet structure of the present invention, the fiber in the pellet structure The length and distribution are defined, but not the fiber length and distribution of the molded product after injection molding or extrusion molding.

The method for producing the structure of the present invention can be produced by a combination of known methods. However, these known methods result in a multi-step process and cannot be said to be a method of high productivity. In a method for producing a fiber-reinforced thermoplastic resin structure by melt-kneading a thermoplastic resin and a continuous reinforcing fiber with an extruder, the molten thermoplastic resin and the reinforcing fiber are mixed with at least one of a screw surface and / or a cylinder inner wall. The degree of opening of the reinforcing fibers and / or fibers in the thermoplastic resin matrix by the comb action of the deformed surface by passing the control mechanism formed by a screw and / or a cylinder whose surface has been deformed. This is a method of controlling the length.

The screw and / or cylinder-processed extruder for controlling the degree of opening and the fiber length of the continuous reinforcing fiber of the present invention is a single-screw or multi-screw extruder having an internal structure. It refers to an extruder that includes a mechanism for controlling the degree of opening of continuous reinforcing fibers and the fiber length. The continuous reinforcing fiber is wound into the extruder by the shearing force between the screw flight and the cylinder, and advances while winding around the screw. Usually, the resin flows through the grooves of the screw, but the reinforcing fibers of the present invention advance over the screw flight. Looking at the screw cross section, since the flight portion is a part of the entire circumference, the winding speed and the peripheral speed of the outermost circumference of the screw have a certain deviation as shown in FIG. Figure 1 shows screw diameter 3
It is the graph which showed the relationship between the glass roving winding-in speed using the 0-mm twin-screw extruder and polyethylene terephthalate, and the screw rotation speed. Therefore, by performing various processes on the outer peripheral portion of the screw and the inner wall of the cylinder that move relatively faster than the wound reinforcing fiber, a "comb" effect can be exerted on the reinforcing fiber between the screw and the cylinder.

As a specific example of the control mechanism, a kneading part or at least a part of a circular or elliptical cylinder part may be subjected to uneven processing on the flight of the screw. The method of forming the irregularities is not particularly limited, but cutting, grinding,
Blasting or the like can be adopted. Examples of the shape of the unevenness include a comb shape having grooves and projections, a shape having grooves and projections formed at a specific angle, and a shape having grooves formed vertically and horizontally to form a mesh. It is desirable that the tip of the projection be formed at an acute angle, and it is not preferable to form the trapezoidal shape and exert a crushing action because the fiber length becomes extremely short. When the fiber length of the reinforcing fiber is long and the fiber is opened to a single fiber, it is desirable to provide a circle or an elliptical cylinder without flight on a part of the screw, and to provide a projection parallel to the circumferential direction on the circumference. The pitch should be small. When relatively bundled fibers are desired to be left, the pitch may be increased or random protrusions or grooves may be provided in the circumferential direction. In this way, it is possible to control the degree of opening and the fiber length of the continuous reinforcing fibers to the desired values. It is desirable that the control mechanism is provided adjacent to a continuous reinforcing fiber feeding section. If it is too far away from the charging section,
As described in Japanese Patent Publication No. 7, the reinforcing fibers are frayed between the ordinary screw flight and the cylinder before reaching the control mechanism, which makes it difficult to control the fiber length and the degree of fiber opening, which is not desirable. Further, as described in Japanese Patent Application Laid-Open No. 4-125110, it is not desirable to provide a normal kneading section or a backflow section after the charging section because the reinforcing fibers are broken there. If a kneading section is provided between the charging section and the control mechanism section, the reinforcing fibers are cut as in the case described above, and the control becomes impossible. Furthermore, it is not desirable to provide a kneading section after the control mechanism section, since the fibers are damaged unless the fiber length is particularly shortened.

The continuous reinforcing fiber feeding section is provided downstream of the resin melting section, and is fed into the molten resin. If the resin is introduced at the same time as the resin, the fibers are cut when the resin is melted, and it is not preferable because the fibers cannot be controlled. In general,
The vent of the extruder can be used as the fiber inlet.

Although the extruder is not particularly limited, a multi-screw extruder such as a twin-screw extruder having a unit structure is particularly convenient. As the multi-screw extruder, the most common twin-screw extruder is preferable, and any type of co-direction, different direction, meshing type, non-meshing type may be used. Further, as the screw, a deep groove, a shallow groove, a single-thread, a two-thread, a three-thread screw or the like can be used. Compared with the single screw extruder, the twin screw extruder can control the resin supply amount and the screw rotation speed independently, so that it is easier to control the addition amount of the reinforcing fiber. Further, the unit structure is advantageous in that a control mechanism for controlling the degree of opening and the fiber length can be easily provided, and the position thereof can be easily changed.

For the purpose of preventing deterioration in physical properties and poor appearance due to volatile components generated from resin and fibers and bubbles embraced by the reinforcing fibers, a deaeration port is provided after the opening degree and fiber length control mechanism. Is desirably provided. In the case of deaeration, it is desirable to seal the upstream part of the deaeration port using a known short flight pitch or shallow groove screw, and further using a reverse flight or kneading disc, but this may damage the reinforcing fibers. Need to be done.

On the flight of the screw after the fiber supply, it is important to provide a kneading section, or at least a part of a circular or elliptical cylindrical part and / or a control mechanism part having irregularities on at least a part of the inner wall of the cylinder. There are the following examples.

FIGS. 2a, 2c, and 2e are side views of an elliptical cylinder portion preferably processed in the present invention, and FIGS. 2b, 2d, and 2f are cutaway perspective views of a cylinder processed in a preferable manner in the present invention. Fig. 2a shows the distance between the cylinder and screw outer diameter of 0.1 to 5 mm.
This is an example of a screw having a certain degree of clearance, and has a protrusion with a specific pitch and depth in the circumferential direction. The pitch and depth can be changed depending on the desired degree of control.
If the pitch is narrow, it becomes easy to form a single fiber, and if it is long, the fiber bundle tends to remain. B. Is an example in which similar processing is performed on a cylinder, and a. b. Each of them can be used alone or in combination. When used in combination, the peaks and valleys of the protrusions can be engaged with each other, or the peaks can be brought close to each other. c. And d. Is an example of a groove intersecting at about 45 degrees, wherein a. , The fiber length tends to be shorter. E. And f. Is an example in which projections are provided at random, and the fibers of the bundle tend to remain. Further, although the case where the screw cross section is circular is illustrated, an elliptical shape is also possible. In particular, in the case of a mesh type twin screw extruder, an elliptical shape is desirable in order to maintain self-cleaning properties. Further, processing may be partially performed, or different processing may be used in combination. Furthermore, in order to control the degree of fiber opening and the fiber length, the length of the control mechanism may be changed, the diameter may be changed at both ends if necessary, or a combination of projections having different pitches and depths may be used. The preferred length of the control mechanism is 0.1 to 10 times, more preferably 0.2 to 5 times the screw diameter. FIGS. 3a, 3c and 3e are side views of a double-start screw with a preferred processing on the screw flight,
b, d, and f are cutaway perspective views of a cylinder whose inner wall surface is preferably processed. These are more effective when the fiber bundle is to be left than in the example of FIG. In addition, the present invention can be applied to a single-thread or three-thread screw. The present invention is not limited to these examples, but encompasses all processes having a function such as "comb" according to the desired degree of fiber opening and fiber length. Further, in the case of a multi-screw screw, it is possible to process only one screw or all screws or any number of screws.

The thermoplastic resin used in the present invention is not particularly limited as long as it can be molded by an extruder. Examples thereof include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and styrene. -Butadiene-acrylonitrile copolymer, aliphatic polyamide such as nylon 11, nylon 12, nylon 6, nylon 66, etc., aromatic polyamide which is a copolymer of aliphatic nylon and terephthalic acid, various copolymerized polyamides, polycarbonate, polyacetal Polyesters such as polymethyl methacrylate, polysulfone, polyphenylene oxide, polybutylene terephthalate, polyethylene terephthalate, polycyclohexanediethylene terephthalate, polybutylene naphthalate and the like; Polymers, copolyester them polyesters and polyester soft segments such as polyether or polycaprolactone such as a hard segment and polytetramethylene glycol, KOKOKU 3-
Thermotropic liquid crystal polymers, polyphenylene sulfide, polyether ether ketone, polyether sulfone, polyether imide, polyamide imide, polyimide, polyurethane, polyether amide, polyester amide and the like described in US Pat. May be used alone or in combination of two or more.

Most preferred resins are polybutylene terephthalate, polyethylene terephthalate, polycyclohexane dimethylene terephthalate, polyethylene terephthalate copolymer liquid crystal polymer, nylon 11, nylon 12, nylon 6, nylon 66, aromatic nylon, polyphenylene sulfide, ABS resin. It is.

As the continuous reinforcing fibers used in the present invention, it is desirable to use a roving in which continuous single fibers are bundled. The reinforcing fiber is not particularly limited as long as it is generally used for reinforcing a resin. Glass fiber, carbon fiber, metal fiber and organic fiber (nylon, polyester, aramid, polyphenylene sulfide, liquid crystal polymer, Although acrylic and the like can be used, glass fiber and carbon fiber are most desirable.

The degree of opening and the ease of controlling the fiber length vary depending on the type of these reinforcing fibers. In the case of glass fibers, generally used E glass and T glass having high strength and high elastic modulus are suitable. In the case of carbon fiber, it tends to break more easily than glass fiber, so the length of the control mechanism is shortened, and the fiber length and degree of opening are controlled using carbon fiber with higher strength and high elastic modulus. It is desirable to do.

Further, in the case of organic fibers, they are generally very hard to be broken, so that the fiber length tends to be difficult to control. Since the easiness of breakage depends on the type and strength of the fiber, it is necessary to control the fiber length in combination with the screw processing shape.

The fiber diameter is not particularly limited as long as it is usually used for reinforcing a resin, and fibers having a diameter of 1 to 20 μm can be preferably used. In particular, the effect of improving the mechanical properties of small diameter fibers of about 1 to 9 μm is great. Although there is no particular limitation on the number of bundles of fibers, a single fiber or a monofilament is
A bundle of 0000 is desirable in terms of handling.

Usually, the roving of these reinforcing fibers can be used after being subjected to a surface treatment such as a silane coupling agent for improving the interfacial adhesion to the resin. For example, a known surface treatment such as Japanese Patent Publication No. 4-47697 can be applied to a polyester resin. These surface treatments may use previously treated reinforcing fibers, or may be performed immediately before the reinforcing fibers are introduced into the extruder to continuously produce the structure of the present invention. The ratio between the thermoplastic resin and the fibers is not particularly limited, and a fiber-reinforced thermoplastic resin composition and a molded article can be produced at an arbitrary composition ratio depending on the final use purpose. Is 0.5 to 90% by weight, more preferably,
1 to 70% by weight is preferable from the viewpoint of mechanical properties and surface smoothness.

The fiber-reinforced thermoplastic structure of the present invention is obtained by extruding and pelletizing a rod-like structure using an extruder and a strand die provided with a specific degree of opening and a fiber length control mechanism. Can be a reinforced thermoplastic pellet structure. This pellet structure can be molded by a known molding method such as injection molding, injection press molding, extrusion molding of tubes, pipes and sheets, and blow molding, and is a molded product having better fluidity and appearance than the conventional pultrusion method. Is obtained. At the time of molding, in order to suppress breakage of the reinforcing fibers, it is desirable to increase the shape of the nozzle or gate and to set the groove depth of the molding machine screw to be equal to or larger than the pellet size.
Further, the present invention also includes a sheet structure obtained by using a sheet die, using a polishing roll or a rolling roll, and further using a double belt press or the like. At this time, it can be laminated with a fiber mat or another thermoplastic or crosslinked resin sheet. In the case of a sheet, it is desirable to make it as a single fiber as much as possible,
A molded article having good fluidity such as stamping molding and having a good appearance can be obtained. Further, the present invention is obtained by providing the control mechanism of the present invention in an injection molding machine, a blow molding machine, a tube or a pipe, a screw or a cylinder of a sheet molding machine, controlling the degree of opening and the fiber length, and simultaneously molding. Various structures are also included.

As a feature of the preferred production method of the present invention,
Alloying of a known thermoplastic resin and addition of various additives can be performed at the same time.

In order to impart desired properties to the fiber-reinforced thermoplastic resin structure according to the present invention, known materials generally used for thermoplastic resins, for example, antioxidants, heat stabilizers, ultraviolet absorbers Known stabilizers such as agents, antistatic agents, flame retardants, flame retardant aids, coloring agents such as dyes and contents,
Lubricants, plasticizers, crystallization accelerators, nucleating agents and the like can be added. In addition, glass flakes, glass powder, glass beads, silica, montmorillonite, quartz, talc, clay, alumina, carbon black, wollastonite,
It is also possible to mix inorganic fillers such as mica, calcium carbonate and metal powder at the same time.

Next, a specific example of a preferred production method of the present invention will be described with reference to the drawings. FIG. 4 is an overall sectional view of a twin-screw twin-screw extruder preferably used in the present invention.
The thermoplastic resin is supplied from the supply port 4 and melted while being conveyed in the extrusion direction by the screw 6, and completely melted in the kneading zone 7. After that, the fibers in the roving state are supplied from the inlet 5 for the reinforcing fibers, and the molten resin and the fibers are sent to the screw tip by the screw composed of the full flight 8 of the forward screw.
After the fiber is opened and the fiber length is controlled by the control mechanism 9 adjacent to the inlet, the fiber-reinforced thermoplastic resin structure 11 is obtained through the die 10. In addition, it is also possible to form the uneven surface forming part 13 on the cylinder inner wall 12 corresponding to the screw uneven surface forming part 9.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Each property value shown in Examples and Comparative Examples was measured for 10 samples.

The method for evaluating the Izod impact strength is AST
It was measured according to MD-256, and the flexural modulus was evaluated as A
Measured according to STM D-790. In the case of a sheet, a test piece was cut out from the sheet and measured. In the observation of the fibers in the composition, a part of the molded product was burned with only the thermoplastic resin in an electric furnace at 500 ° C., and the fiber content and the fiber length were measured. As the fiber length, a weight average fiber length (Lw) and a number average fiber length (Ln) were obtained, and a distribution Lw / Ln was obtained. The corner portion of the molded product was similarly burned to measure the fiber content. Regarding the degree of fiber opening, the structure processed to a thickness of 1 mm was observed with a soft X-ray photograph, and X was determined when there was more than 3 mm square of shading unevenness, and Δ was determined when it was 3 mm or less, and O was determined when there was no unevenness. did. The discharge stability during sheet extrusion was determined as X when partial die clogging occurred, as Δ when there was unevenness in the discharge speed in the sheet width direction, and as ○ when there was no unevenness in the discharge speed in the sheet width direction.

The relative viscosity of the resin was measured at 25 ° C. after dissolving it in orthochlorophenol at a concentration of 0.5 g / dl. Example 1, Comparative Example 1-3 As shown in FIG. 4, a screw diameter of 30 mm having two supply ports in the extrusion direction, L / D4
5.5 co-rotating twin-screw extruder (T, manufactured by Japan Steel Works, Ltd.)
EX30), using two threads to engage each other 3.5 m
m, and screw elements composed of five kneading disks inclined at 45 degrees with L / D = 1 between the first resin supply port and the reinforcing fiber input port are combined in reverse order. Provided. L on the discharge side of the reinforcing fiber input port
Via a full flight screw with / D = 1, FIG. 2a.
(Pitch 1 mm, tip angle 30 degrees) L / D processed
The control mechanism was formed using a neutral element having an oval cross section of 0.75. A polyethylene terephthalate pellet (relative viscosity: 1.35) is supplied to a resin supply port by a screw-type pellet supply device, and a diameter of 1 mm is supplied from a fiber input port.
7 μm, 2200 g of glass roving per 1000 m (manufactured by NEC Corporation) was introduced, and cylinder temperature 2
At a temperature of 80 ° C and a screw rotation speed of 200 rpm, a thickness of 4
The sheet was extruded into a sheet from a die having a width of 50 mm and a width of 50 mm, and cooled with a casting roll to obtain a fiber reinforced sheet. The glass fiber content of the obtained sheet was 25% by weight.

For comparison, a porous web sheet having a glass fiber content of 25 wt% was prepared by the same papermaking method as in JP-A-3-7307 using the above polyethylene terephthalate powder and chopped strands having a fiber diameter of 17 μm and a fiber length of 13 mm. It was created. Five of these webs are stacked and about 28
Press molding was performed at 0 ° C. to obtain a sheet (Comparative Example 1).

Further, the same polyethylene terephthalate and glass fiber as in Comparative Example 1 were mixed in a Henschel mixer in the same manner as in JP-A-63-9511, and extruded in a sheet form using a ram extruder. A sheet having a fiber content of 25% was obtained (Comparative Example 2).

Further, using the same polyethylene terephthalate and glass roving as in the example, cutting was performed to a pellet length of 13 mm by a known crosshead die-type pultrusion method to obtain a long fiber reinforced pellet having a glass content of 25 wt%. The pellets were press-formed into a sheet at about 280 ° C. (Comparative Example 3).

As shown in Table 1, when the fiber length, distribution, and mechanical properties of the sheet were measured, excellent mechanical properties were obtained in this example. However, in Comparative Examples 1 and 2, specific properties were obtained by melt-kneading. Since no fiber length distribution was obtained, only a low impact strength was obtained despite the long fiber length.
In Comparative Example 3, since the glass roving was not opened, the resin and the glass fiber were separated by press molding, so that a uniform sheet could not be obtained, and the mechanical properties could not be measured. Example 2-4, Comparative Example 4-5 FIG. (Pitch 0.5mm, Tip angle 60
Degree), FIG. 2e. (Rz = 90 μm)
D = 0.75, neutral element with elliptical cross section (Examples 2, 3) and FIG. (Serial processing, groove depth 1 mm) Using a full-flight element with L / D = 1 (Example 4), screw rotation speed 150
A fiber-reinforced sheet was obtained after extrusion in the form of a sheet and cooling with a casting roll in the same manner as in Example 1 except that the extrusion was carried out at rpm.

For comparison, a forward full flight without processing in place of the processed forward full flight element of Example 4 (Comparative Example 4) and a neutral element without processing in place of the processed neutral element of Example 2 (Comparative Example) A sheet using Example 5) was similarly formed.

As shown in Table 2, in Comparative Examples 4 and 5, the die pressure was high and the discharge unevenness occurred, and the degree of opening of the glass fibers in the sheet was uneven. However, in this example, a good sheet was obtained. . Example 5, Comparative Example 5-6 The glass fiber content was 45 wt.
%, And extruded into a 4 mm-diameter round bar instead of a sheet, and pelletized to a length of about 10 mm to produce a long fiber reinforced pellet in the same manner as in Example 2.

For comparison, in the same screw arrangement as in Example 5, a method of adding a 10 mm-long chopped strand from the fiber inlet (Comparative Example 6) was carried out in the same manner as in Example 1 using a 10 mm-long chopped strand. Pellets were produced by a method in which a suitable kneading disk was used even after the fiber inlet (Comparative Example 7), and further by a known pultrusion method (Comparative Example 8).

As shown in Table 3, in the case of Comparative Example 6, the chopped strand was not wound around the screw, so the fiber was not opened, the clogging of the die occurred, and pelletization was not possible. Further, in Comparative Example 8, if the strand take-up speed was increased, the strand was cut, resulting in poor productivity and poor fluidity during injection molding.
The pellets of this example had good fluidity during molding and had mechanical properties comparable to those of the pultrusion method, despite the fact that the fiber length of the injection molded product was short. [Embodiment 6 and Comparative Example 9] L / D = 1 at a position adjacent to the vent port discharge port side of an injection molding machine having a full flight screw.
Figure 2e. And f. Processing (groove depth, pitch 1m each)
m), a polybutylene terephthalate resin (relative viscosity 1.4
5) was injection-molded at about 250 ° C. by supplying the glass roving of Example 1 from the vent port.

In addition, a comparison was made with the case where no processing was performed (Comparative Example 9).

As shown in Table 4, in Example 6, the fluidity at the time of molding was good, and the appearance of the molded product did not deteriorate. Example 7, Comparative Example 10 Blow molding was performed in the same manner as in Example 6, except that a blow molding machine for a full flight screw was used.

Further, a comparison was made with the case of using a non-processed full-flight screw in place of the processed full-flight screw in Example 7 (Comparative Example 10).

In the seventh embodiment, Lw in the molten parison
= 4.9 mm, Lw / Ln = 2.1, and a stable molded article with stable discharge was obtained.
At 8.9 mm, Lw / Ln = 3.4, a large amount of burrs occurred because the parison touched right and left without sagging vertically. Example 8-11, Comparative Example 11-13 FIG. In the same manner as in Example 5, except that the screw element and polybutylene terephthalate were used, 5 mm-long pellets having different fiber contents were produced, injection-molded, and the physical properties were measured (Table 5).

For comparison, glass roving was introduced from the resin inlet instead of from the fiber inlet.

As shown in Table 5, good physical properties were obtained with the pellet structure of the present invention (Examples 8-11). [Examples 12-15, Comparative Example 14] Carbon fiber (manufactured by Toray)
Except for using a trader "T-300B) roving, the same method as in Example 5 was used to produce a 3 mm long pellet with a different fiber content and injection molding.

For comparison, the resin was also introduced from the resin inlet instead of the fiber inlet.

As shown in Table 6, in the pellet structure of the present invention (Examples 12 to 15), the fiber length was long and good physical properties were obtained.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

[Table 6]

[0059]

As is apparent from the above description and Examples, in the present invention, the knitting action is performed while controlling the degree of fiber opening to uniformly disperse the reinforcing fibers and keeping the weight-average fiber length long. By making a specific fiber length distribution, it is possible to obtain a fiber-reinforced thermoplastic resin structure excellent in fluidity, mechanical properties, surface smoothness, etc., and further, continuous reinforcing fibers are caught in the screw In addition, by the process performed on the screw outer periphery and / or the cylinder inner surface, a comb action is exerted on the continuous reinforcing fibers, and the degree of opening and the fiber length of the reinforcing fibers can be controlled. As a result, it is possible to obtain a fiber-reinforced thermoplastic structure having high productivity and good fluidity during molding, excellent mechanical properties and surface properties, which have not been obtained conventionally, and which has extremely high industrial value. It is.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a winding speed of glass roving and a screw rotation speed using a twin screw extruder having a screw diameter of 30 mm and polyethylene terephthalate. The broken line indicates the peripheral speed of the outermost screw flight,
The solid line shows the roving entrainment speed.

FIG. 2 is a cutaway perspective view of a screw and a cylinder that have been subjected to a preferred working in the present invention.

FIGS. 3a, 3c and 3e are side views of a screw which has been subjected to a preferred working in the present invention, and FIGS. 3b, 3d and 3f are cutaway perspective views of a cylinder which has been subjected to a preferred working in the present invention.

FIG. 4 is an overall sectional view of an extruder provided with two supply ports preferably used in the present invention.

[Explanation of symbols]

 1. Screw full flight section 2. Flight surface 3. 3. Inner wall of cylinder First supply port 5. Second supply port 6. Screw 7. Kneading zone 8. 8. Full flight of forward screw Screw uneven surface forming part 10. Dice 11. 11. Fiber-reinforced thermoplastic resin structure 12. Inner surface of cylinder Uneven surface forming part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08L 101: 00 C08L 101: 00

Claims (6)

[Claims] 1. A ratio of a weight average fiber length to a number average fiber length of a uniformly dispersed reinforcing fiber containing a thermoplastic resin and a reinforcing fiber is from 1.1 to 3, and the weight average fiber length is from 2.0 mm to 2.0 mm. 1
A fiber-reinforced thermoplastic resin structure having a size of 5 mm. 2. The weight-average fiber length is 4.5 mm to 12 mm.
The fiber-reinforced thermoplastic resin structure according to claim 1, wherein: 3. The fiber-reinforced thermoplastic resin structure according to claim 1, wherein the fiber-reinforced thermoplastic resin structure has a sheet shape or a rod shape. 4. The fiber-reinforced thermoplastic resin structure according to claim 1, wherein the fiber-reinforced thermoplastic resin structure is obtained by extrusion molding. 5. A fiber-reinforced thermoplastic pellet structure obtained by cutting the fiber-reinforced thermoplastic resin structure according to claim 3 or 4. 6. The pellet length is at least の of the weight average fiber length of the fiber reinforced thermoplastic resin structure before cutting, and the weight average fiber length in the pellet is 0.1% of the pellet length.
The fiber-reinforced thermoplastic pellet structure according to claim 5, wherein the number is 9 or less.