JPH05192926A - Material, method and apparatus for molding liquid crystal resin composite - Google Patents

Abstract

PURPOSE:To obtain a molding material having a proper dimension and high reinforcing effect by subjecting a composition consisting of a thermoplastic matrix resin and a liquid crystal resin having liquid crystal transition temp. higher than the m.p. of the matrix resin to extrusion molding at the liquid crystal transition temp. or higher to form a plurality of filaments and gathering the filaments in the radius direction thereof. CONSTITUTION:A liquid crystal resin to be used pref. has an m.p. higher than that of a matrix resin by 20 deg.C or higher and the liquid crystal transition point thereof is higher than the m.p. of the matrix resin. The compounding amount of the liquid crystal resin is adjusted to a fiberizing region of phase reversal or less as the whole of a compsn. This compsn. is extruded at temp. of the liquid crystal transition point or higher at a shearing speed forming the liquid crystal resin into a fibrous shape within the matrix resin to form a plurality of filaments or films. These filaments are allowed to meet with each other in the radius direction thereof to form a strand or the films are laminated or wound or folded in the lateral direction thereof to be subjected to stretching treatment. Thereafter, the strand is cut to be formed into pellets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material for a liquid crystal resin composite used as a molding material, a molding method thereof and a molding apparatus thereof.

[0002]

2. Description of the Related Art In recent years, fiber reinforced plastic (FRP)
In order to improve the processability of the composite, instead of this, a composite has been proposed in which a matrix resin made of a thermoplastic resin is mixed with a liquid crystal resin and the liquid crystal resin is fibrillated and reinforced at the time of molding (Japanese Patent Application Laid-Open No. 2000-242242). 62-116666, JP-A-1-158807).

[0003]

In molding this kind of liquid crystal resin composite, as shown in FIG. 1, a matrix resin which is a thermoplastic resin is mixed with a liquid crystal resin having a liquid crystal transition point higher than its melting point at a predetermined ratio. It is blended, melt-extruded at a temperature higher than the liquid crystal transition temperature of the liquid crystal resin, cooled and stretched, and the resulting strand is cut into a predetermined size and used as a molding material for injection molding or blow molding. To The mechanical strength of this molded product can be improved by fiberizing the liquid crystal resin in the extrusion direction during the melt extrusion. Further, according to the knowledge of the present inventors, the physical properties can be improved by stretching in the extrusion direction, that is, the fiber longitudinal direction of the liquid crystal resin. Therefore, it is preferable to stretch the liquid crystal resin that is fibrous in the matrix resin as much as possible in order to enhance the reinforcing effect of the fibrous liquid crystal resin. However, in order to fiberize the liquid crystal resin in the matrix resin by extrusion molding, At the time of extrusion, it is necessary to secure a resin shear rate above a certain level, and the extrusion diameter is usually small. Furthermore, if this extruded product is stretched, it will be in the form of fine fibers, and it will not have suitable dimensions for use as a molding material.
There is a limit to the stretch ratio. Therefore, it is an object of the present invention to provide a molding material which has a suitable size as a molding material and has a high reinforcing effect by fiberizing a liquid crystal resin, and a molding method and apparatus therefor.

[0004]

According to the present invention, in order to enhance the reinforcing effect of the liquid crystal resin, it is necessary to utilize the interaction between the fiberization of the liquid crystal resin and its stretching in the matrix resin in the molding material. However, if the extruded strands are joined as they are or while drawing to form a thick strand, and if necessary, this thick strand is drawn, the dimensions required as a molding material can be increased while processing with a large draw ratio. It was made paying attention to the fact that it can be provided, and a plurality of compositions obtained by extruding a composition composed of a matrix resin made of a thermoplastic resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin at a liquid crystal transition point or higher. The filaments are gathered in the radial direction, or a film extruded into a sheet at the liquid crystal transition point or more is laminated in the thickness direction. , Or in the film width direction in the winding or folded consisting molding material.

The thermoplastic resin used in the present invention includes ABS resin, ethylene-vinyl acetate copolymer, fluororesin, acetal resin, amide resin, imide resin, amide imide resin, acrylic resin, vinyl chloride resin, olefin resin, polyester. , Polycarbonates, polyacrylates, polyphenylene oxides, polystyrenes, melt-moldable resins such as thermo-plastic polyurethanes, modified products thereof, and blended products (including those called polymer alloys).

On the other hand, the liquid crystal resin is not particularly limited as long as it has a melting point higher than that of the above matrix resin, preferably 20 ° C. or higher, but thermoplastic liquid crystal polyester and thermoplastic liquid crystal polyesteramide are preferable, Specifically, liquid crystal resins such as Vectra, Econol, and Cider under the trade names are commercially available. .

It is necessary to mix the liquid crystal resin with the matrix resin so that the composition as a whole has a fiberizing region below its phase inversion (see FIG. 2). For example, when the matrix resin is a polyamide resin, 40
-80% by weight, 30 to 75% by weight in the case of ABS (acrylic-butadiene-styrene copolymer) resin, 3 to 70% by weight in the case of polycarbonate (PC) / ABS resin, 2 in the case of PC / PBT resin. -60% by weight, 3 to 65% by weight in the case of polyphenylene oxide (PP0) / nylon (PA6), 3 to 60% in the case of modified PPO resin
A suitable range is 2 to 70% by weight for polypropylene, 3 to 70% by weight for polycarbonate, and 10 to 70% by weight for PBT resin.

A composition comprising the above-mentioned thermoplastic matrix resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin has a resin shear rate at a temperature above the liquid crystal transition point and at which the liquid crystal resin becomes fibrous in the matrix resin. To form a plurality of filaments or films. At that time, the resin shear rate during extrusion is 3 ×
10 ² to 10 ⁵ sec ^-1 , preferably 3 × 10 ² to 10 ⁴ se
It is necessary to set c ⁻¹ , more preferably 3 × 10 ^{2 to} 5 × 10 ³ sec ⁻¹ .

Strands formed by merging are once cooled or are continuously subjected to a stretching treatment without cooling. The stretching ratio (cross-sectional area of extruded product / cross-sectional area after stretching) is preferably 11 or more and 120 or less. Resin shear rate 3 × 10 ²
The liquid crystal resin in the matrix resin extruded at -10 ⁵ sec ^-1 shows a remarkable increase in tensile strength due to stretching at a stretching ratio of 11 to 120 (Fig. 3 (a)), while the shear rate is too low. This is because (10 ² sec ⁻¹ or less), as shown in FIGS. 3B and 3C, an increase in tensile strength due to stretching cannot be expected.
The drawn strand or film is cut into a predetermined size and used as a molding material.

In carrying out the above-mentioned molding method, a porous die capable of simultaneously extruding a composition comprising a thermoplastic matrix resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin into a plurality of filaments in the coaxial direction at the same time. Alternatively, an extruding device having a film-like die for extruding into a film state, and a confluent device for consolidating a plurality of filaments extruded from the extruding device in the radial direction or for winding or folding the film in the width direction are joined together. A molding device for molding pellets is used which comprises a device for stretching the strands.

[0011]

EFFECTS OF THE INVENTION According to the present invention, a thin or thin molding material that has been stretched at a high draw ratio, which secures a necessary shear rate during extrusion and, in some cases, improves tensile strength, is joined into a strand shape. By doing so, the required diameter of the strand required for molding can be secured. In addition,
The final strand diameter after stretching is selected as the diameter and the number of filaments to be merged in relation to the stretching ratio, or the thickness and width of the film to be merged, and the diameter of the stretched strand is 0.3 as a filament winding material.
It is necessary to consider so as to be at least 1 mm, and preferably for other molding materials to be at least 1 mm.

[0012]

EXAMPLES The present invention will be described below based on specific examples.
4 to 8 show an apparatus for carrying out a merging method in which a large number of filaments are simultaneously extruded and merged to form a strand, and FIGS. 9 to 11 show one film extruded and folded from both sides. 1 shows an apparatus for carrying out a joining method for forming a strand. In FIGS. 4 and 5,
It consists of an extrusion device 1, a merging device 2 and a stretching device 3,
As shown in FIGS. 7 and 8, the extrusion device 1 is such that a porous die 12 having five holes is screwed to the tip of an extrusion nozzle 11 with a screw 14 and attached to a main body (not shown) with an annular fixing portion 13. The die is arranged so as to surround a center hole 12a having a diameter of 2 mm and have peripheral holes 12b to 12e having the same diameter gathered at a predetermined position in front, and the filament F extruded from the die is joined by a merging device. Gather at 2 entrances. The merging device 2 includes a pair of generally drum-shaped rollers 2 having a pair of guide members 21 arranged at the inlet and a small diameter portion 22b sandwiched between the large diameter portions 22a and 22a at both ends.
2, the plurality of filaments F joined by the pair of small-diameter portions 22b are pressed and gathered in the radial direction to form a strand S. The filaments F may be twisted together to form the strands S when they join. The strand S reaches the drawing device 3.
The stretching device 3 rotates a pair of stretching rollers 30, 30 in mutually opposite directions to apply a tensile force to the strand S in its longitudinal direction to perform stretching. On the other hand, in FIGS. 9 and 10, as in the above embodiment, the extrusion device 1, the merging device 2 and the stretching device 3 are configured.
A normal film extrusion die is used as the extrusion device. On the other hand, the merging device 4 is composed of a plurality of winding forming rolls 41 and 42 and a pressure-bonding forming roll 43. As shown in FIG. 11, the winding forming rolls 41 and 42 are formed with a winding portion 41c that is curved outwardly from the small-diameter body portion 41a to the large-diameter head portion 41b. When it comes into contact with the turning portion 41c, it is folded inward along the curved shape. Since the curving curvature of the winding portion is set smaller as the film advances, the film is gradually woven inward. The film woven from both sides in this way has a form in which two wound films are adjacent to each other, or at the final stage, the two wound films are paired with a pair of pressure rolls 4.
The strand S is formed by pressing with 3, 43. The strand S reaches the drawing device 3. The stretching device 3 rotates a pair of stretching rollers 30, 30 in mutually opposite directions to apply a tensile force to the strand S in its longitudinal direction to perform stretching. The drawn strand is cut into a predetermined size to be a molding material. (Example 1) PC / ABS as a matrix resin (trade name: Techniace.A 105, manufactured by Sumitomo Nogatac) 80% by weight of aromatic polyester as a liquid crystal resin (trade name: Vectra.A950, manufactured by Polyplastics Co., Ltd.) ) Mixing 20 parts by weight of powder and using a twin-screw extruder (manufactured by Plastic Engineering Laboratory Co., Ltd.) equipped with a porous die shown in FIGS. 7 and 8, screw diameter 30 mm, resin temperature 290 ° C., screw rotation It is set to several 100 rpm, and it is extruded in the form of 5 2 mmφ strands at a shearing rate of 1700 sec ^-1 , and is subjected to a merging device to form strands having a diameter of 1 mm. This was stretched using a stretching machine (manufactured by Mazda Motor Corporation). The obtained strand-shaped composite for molding (diameter 1 mm) is cut into a length of 3 mm to obtain a pellet material. next,
The pellet material was set to a resin temperature of 250 ° C. and an injection pressure of 1000 Kg / cm ² using an injection molding machine (220 tons, manufactured by Toshiba Machine Co., Ltd.) and a test piece mold.
A molded product was obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an overall molding method of a material for molding a liquid crystal resin composite and a molding method using the same.

FIG. 2 is an explanatory diagram showing a change in the state of the composite, which is affected by the content of the liquid crystal resin with respect to the matrix resin of the liquid crystal resin composite.

FIG. 3 is a graph showing the influence of the interaction between the extrusion shear rate and the draw ratio on the tensile strength in a liquid crystal resin composite.

FIG. 4 is a schematic front view showing a first method of the molding method according to the present invention.

FIG. 5 is a schematic plan view of the first method.

6 is a perspective view of a filament merging roll used in the first method of FIGS. 4 and 5. FIG.

FIG. 7 is a front view of an extrusion device including a porous die used in the first method.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a schematic front view showing a second method of the molding method according to the present invention.

FIG. 10 is a schematic plan view of the second method.

FIG. 11 is a functional explanatory view of a filament merging roll used in the second method of FIGS. 9 and 10.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Extrusion device, 11 Extrusion nozzle, 12 Extrusion die 2 and 4 Joining device, 22, 41, 42, 43 Forming roll 3 Stretching device, 30 Stretching roll

Claims (4)

[Claims] 1. A plurality of filaments formed by extruding a composition comprising a matrix resin made of a thermoplastic resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin at a temperature equal to or higher than the liquid crystal transition point in the radial direction thereof. Molding material that is assembled. 2. A film obtained by extruding a composition comprising a matrix resin made of a thermoplastic resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin into a sheet shape at a temperature equal to or higher than the liquid crystal transition point in the film thickness direction. A forming material that is laminated or wound or folded in the width direction of the film. 3. A composition comprising a thermoplastic matrix resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin is converted into a fibrous resin at a temperature above the liquid crystal transition point and the liquid crystal resin in the matrix resin. Linear or sheet-like extrusion is performed at such an apparent shear rate to form a plurality of filaments or films, and the plurality of filaments are aggregated in the radial direction, or the films are laminated in the film thickness direction, or in the film width direction. A method for forming a molding material, which comprises winding or folding the material. 4. A porous die capable of simultaneously extruding a composition comprising a thermoplastic matrix resin and a liquid crystal resin having a liquid crystal transition point higher than the melting point of the resin into a plurality of filaments in a coaxial direction, or a film shape extruded into a film state. An extrusion device equipped with a die, a confluence device for collecting a plurality of filaments extruded from the extrusion device in the radial direction thereof, or a device for laminating films in the film thickness direction, or a confluence for winding or folding the film in the film width direction. An apparatus for molding pellets for molding, comprising: a device.