JPH0857916A - Method for molding liquid crystal resin composite - Google Patents

Abstract

PURPOSE: To effectively suppress rupture of liquid crystal fibers by action of shear force in a plasticizing fusion process by a method wherein plasticizing temperature is set within a temperature range wherein the square root of the ratio of the tensile strength of liquid crystal fibers to the particle size of thermoplastic matrix resin is higher than those in the other temperature ranges. CONSTITUTION: Molding material PT wherein thermoplastic liquid crystal resin having a liquid crystal transition temperature higher than the lowest moldable temperature of thermoplastic matrix resin is combined, in a fibrous manner, in the thermoplastic matrix resin, is kneaded with a plasticizing fusion device 1 consisting of a rotating screw 5. Only the thermoplastic matrix resin is, in such a plasticizing manner, fused to be molded thereby. Herein, the plasticizing temperature is set within a temperature range wherein the ratio of tensile strength σT of liquid crystal fiber to the particle size η of thermoplastic matrix resin i.e., the square root of σT/η comes to be higher than the others.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a liquid crystal resin composite, and more particularly to a method for plasticizing and melting only a matrix resin of a molding material in a plasticizing and melting apparatus equipped with a rotary screw. The present invention relates to a method for molding a liquid crystal resin composite.

[0002]

2. Description of the Related Art Conventionally, as a method of molding a liquid crystal resin composite, a thermoplastic liquid crystal resin and a thermoplastic matrix resin having a minimum moldable temperature lower than the liquid crystal transition temperature of the liquid crystal resin are contained in the matrix resin. In the above, the liquid crystal resin cut to a predetermined length is formed into a fibrous state and the molding material (pellet) is kneaded with a plasticizing and melting device equipped with a rotary screw, and the matrix resin A method of melting and molding only is known (see, for example, JP-A-1-320128). In such a molding method, the pellets internally generate heat by the action of shearing force accompanying the rotation of the screw, and mainly due to this heat, the temperature of the pellets is in the range of the minimum moldability of the matrix resin or more and less than the liquid crystal transition temperature of the liquid crystal resin (Hereinafter, this temperature range is referred to as a mold window.) The temperature is raised to the inside, and only the matrix resin is in a molten state, and molding can be performed while maintaining the fibrous state of the liquid crystal resin.

However, in the above-mentioned conventional molding method, the liquid crystal resin inside the pellets is cut by the action of the shearing force accompanying the rotation of the screw, and the length cannot be maintained at the predetermined length that was aligned before kneading. However, there is a problem that the mechanical characteristics (that is, strength and rigidity) of the molded resin molded product are adversely affected.

A similar problem also occurs when a fiber-reinforced resin using another type of fiber such as glass fiber as a reinforcing material is plasticized and melted in the matrix resin to be molded. Regarding the above problems, for other types of fiber reinforced resin such as glass fiber reinforced resin, the reinforcing fibers compounded in the molding material undergo shearing action in the matrix resin which has begun to be plasticized in the plasticizing and melting apparatus. Various attempts have been made to model the state, set the failure mode of the reinforcing fiber in this model, and analyze the mode to derive the condition for the failure of the reinforcing fiber in the molding material. By deriving the breakage condition of the reinforcing fiber in this way, on the contrary, it becomes possible to find a method / condition for suppressing breakage of the reinforcing fiber at the time of plasticizing and melting.

In this case, in the initial stage of the plasticizing and melting step, first, a layer (so-called melt film) in which the matrix resin is plasticized and melted into a fluid state is formed in a region in contact with the barrel wall surface of the plasticizing and melting device. Therefore, as will be described in detail later, for the reinforcing fiber whose one end side is retained in the part which is not plasticized yet (so-called solid bed) of the molding material, the model in which the other end side protrudes into the melt film Is being considered. Further, as the failure mode of this reinforcing fiber, due to the relative flow of the molten matrix resin in the melt film with respect to the reinforcing fiber (that is, due to the shearing acting on the reinforcing fiber), the bending moment of the reinforcing fiber. Is considered to act, and a mode in which the reinforcing fiber is broken and broken by this bending moment is considered.

[0006]

However, liquid crystal fibers have a large elongation and a low elastic modulus as compared with, for example, glass fibers or the like, and it is unlikely that they will be broken in the same mode as glass fibers or the like. That is, in the case of glass fiber, the breakage mode is set as being broken by being broken by the action of the bending moment as described above,
In the case of liquid crystal fibers having a large elongation, it is generally unlikely that they will be bent by bending like glass fibers.
Therefore, it is considered that the analysis result of the glass fiber cannot be directly applied to the liquid crystal fiber.

Therefore, in the case of liquid crystal fiber, the present inventor
Considering a failure mode in which the material is not broken by bending but is broken by pulling, the failure mode is applied to the above model for analysis. As a result, when the same shearing acts on the liquid crystal fibers, the limit length when the liquid crystal fibers are cut by the tensile force applied due to this shearing is the tensile strength of the liquid crystal fibers (σ _T ) ratio to η)
It has been found that it largely depends on the value of the square root of (σ _T / η). For various matrix resins, the above (σ _T
It has been found that there is a temperature range in which the value of the square root of / η) changes with temperature, and this value is higher than others.

According to the present invention, the limit length for cutting the liquid crystal fiber at the time of plasticizing and melting is the tensile strength of the liquid crystal fiber.
The ratio viscosity of the matrix resin (eta) of (σ _T) (σ _T /
A method for molding a liquid crystal resin composite, which was made paying attention to the square root value of (η), can effectively suppress the breakage of liquid crystal fibers due to the action of shearing force in the plasticizing and melting step. The purpose is to do.

[0009]

Therefore, in the method of molding a liquid crystal resin composite according to the first invention of the present application, the liquid crystal transition in the thermoplastic matrix resin is higher than the minimum moldable temperature of the thermoplastic matrix resin. Thermoplastic liquid crystal resin having a temperature is molded into a fibrous composite material by kneading with a rotary screw type plasticizing and melting device,
A liquid crystal resin composite which is formed by plasticizing and melting only the thermoplastic matrix resin at a temperature in a range not lower than the minimum moldability of the thermoplastic matrix resin and lower than the liquid crystal transition temperature of the thermoplastic liquid crystal resin. In the molding method of the body, the plasticization temperature is set to the tensile strength of the liquid crystal fiber.
the square root of the ratio of viscosity (eta) of the thermoplastic matrix resin (σ _T / η) of (sigma _T) is obtained by and sets the higher becomes the temperature region than the other.

The liquid crystal resin composite molding method according to the second invention of the present application is the same as the first invention, wherein the thermoplastic matrix resin is a polystyrene resin and the plasticizing temperature is 160 to 210 ° C. It is characterized by that.

Further, in the method for molding a liquid crystal resin composite according to the third invention of the present application, in the first invention, the thermoplastic matrix resin is polyamide 6 resin and the plasticizing temperature is 230 to 245 ° C. It is characterized by being.

Further, the method for molding a liquid crystal resin composite according to the fourth invention of the present application is the same as the first invention, wherein the thermoplastic matrix resin is a polybutylene terephthalate resin and the plasticizing temperature is 230. It is characterized by being ˜245 ° C.

Furthermore, in the method for molding a liquid crystal resin composite according to the fifth invention of the present application, in the first invention, the thermoplastic matrix resin is a polypropylene resin, and the plasticizing temperature is 185 to 210. It is characterized in that the temperature is ° C.

Furthermore, the liquid crystal resin composite molding method according to the sixth invention of the present application is the same as the first invention, wherein the thermoplastic matrix resin is an acrylonitrile-butadiene-styrene resin. Is 180
It is characterized by being ~ 230 ° C.

Furthermore, in the method for molding a liquid crystal resin composite according to the seventh invention of the present application, in the first invention, the thermoplastic matrix resin is a modified polyphenylene ether resin, and the plasticizing temperature is 180. It is characterized by being ~ 230 ° C.

[0016]

According to the first invention of the present application, the plasticization temperature is defined as the square root of the ratio (σ _T / η) of the tensile strength (σ _T ) of the liquid crystal fiber to the viscosity (η) of the thermoplastic matrix resin. Since the value of is set to a temperature range where it is higher than other values, the breakage of the liquid crystal fibers in the plasticizing and melting step can be effectively suppressed, and the mechanical properties of the molded product can be improved.

Further, according to the second invention of the present application, basically, the same effect as that of the first invention can be obtained. Particularly, when a polystyrene resin is used as the thermoplastic matrix resin, the plasticization temperature is
By setting the square root value of (σ _T / η) to 160 to 210 ° C., which is a temperature range in which the square root value is higher than others, breakage of liquid crystal fibers in the plasticizing and melting step can be effectively suppressed.

Further, according to the third invention of the present application, basically, the same effect as that of the first invention can be obtained. In particular, when polyamide 6 resin is used as the thermoplastic matrix resin, the plasticization temperature is
By setting the square root value of (σ _T / η) to 230 to 245 ° C., which is a temperature range in which the square root value is higher than others, breakage of liquid crystal fibers in the plasticizing and melting step can be effectively suppressed.

Further, according to the fourth invention of the present application,
Basically, the same effect as that of the first invention can be obtained. In particular, when a polybutylene terephthalate resin is used as the thermoplastic matrix resin, the plasticizing temperature is set to 230 to 245 ° C., which is a temperature range in which the square root value of (σ _T / η) is higher than others. Thereby, the breakage of the liquid crystal fibers in the plasticizing and melting step can be effectively suppressed.

Further, according to the fifth invention of the present application,
Basically, the same effect as that of the first invention can be obtained. In particular, when a polypropylene resin is used as the thermoplastic matrix resin, the plasticizing temperature is set to 185 to 210 ° C., which is a temperature range in which the square root value of (σ _T / η) is higher than others. It is possible to effectively suppress breakage of the liquid crystal fibers in the plasticizing and melting step.

Further, according to the sixth invention of the present application,
Basically, the same effect as that of the first invention can be obtained. Particularly, when acrylonitrile-butadiene-styrene resin is used as the thermoplastic matrix resin, the plasticizing temperature is 180 to 230 ° C., which is a temperature range in which the square root value of (σ _T / η) is higher than others.
By this, breakage of the liquid crystal fibers in the plasticizing and melting step can be effectively suppressed.

Further, according to the seventh invention of the present application,
Basically, the same effect as that of the first invention can be obtained. In particular, when a modified polyphenylene ether resin is used as the thermoplastic matrix resin, the plasticizing temperature is set to 180 to 230 ° C., which is a temperature range in which the square root value of (σ _T / η) is higher than others. Thereby, the breakage of the liquid crystal fibers in the plasticizing and melting step can be effectively suppressed.

[0023]

Embodiments of the present invention will be described below.
First, prior to the explanation of specific examples, a state in which liquid crystal fibers mixed in a molding material undergo a shearing action in a matrix resin which has begun to be plasticized in a plasticizing and melting apparatus is modeled, and the liquid crystal in this model is modeled. The model analysis performed by setting the fiber breakage mode will be described. In the initial stage of the plasticizing and melting step of the molding material, as shown in FIG. 1, first, the barrel wall surface 2a of the plasticizing and melting apparatus is kept at a predetermined high temperature by heating a heater (not shown). A layer MF (so-called melt film: thickness h) in which the matrix resin is plasticized and melted into a fluid state is formed in a region in contact with the wall surface 2a. Then, with respect to the liquid crystal fiber 10 (diameter D) whose one end side is held in the portion SB (so-called solid bed) of the molding material which has not been plasticized yet, the other end side protrudes into the melt film MF by the length L. The model is set.

In this case, assuming that the melt film MF is composed of an isothermal Newtonian fluid, the force F applied to the portion (length L) of the liquid crystal fiber 10 protruding into the melt film MF is equal to the isothermal Newtonian fluid. The force that a cylindrical object placed inside receives from a fluid is expressed by the following equation. F = Cd · ρ · V ² · A / 2 ... where Cd is the drag coefficient, ρ is the fluid density (that is, the density of the molten matrix resin), V is the flow velocity, and A is the cylindrical object with respect to the flow direction (the liquid crystal fiber 10). ) Is the cross-sectional area (projected area).

The drag coefficient Cd is expressed by the following equation using the Reynolds number Re. Cd = 8π / [Re · log (7.4 / Re)] ... Further, the Reynolds number is represented by the following equation, where η is the viscosity of the matrix resin. Re = ρ · V · D / η Further, the projected area A of the object (liquid crystal fiber 10) with respect to the flow direction is expressed by the following equation. Here, L'is a portion (length L) protruding in the melt film MF of the liquid crystal fiber 10.
Is the projected length for the flow direction of. A = ∫ ₀ ^{L ′} D · dx ... Further, the flow velocity V is represented by the following equation, where Vo is the flow velocity on the barrel wall surface 2a. V = Vo x / h ...

In this embodiment, the failure mode of the liquid crystal fiber 10 in the above model is caused by the relative flow of the molten matrix resin in the melt film MF with respect to the liquid crystal fiber 10 (that is, the shearing force acting on the liquid crystal fiber 10). A tensile force acts on the liquid crystal fiber 10 to set a failure mode in which the liquid crystal fiber 10 is broken by pulling instead of being bent by bending as in the case of glass fiber, and the failure mode is applied to the above model. The conditions under which the liquid crystal fiber 10 is damaged are derived. Here, when the angle formed by the liquid crystal fiber 10 and the perpendicular to the barrel wall surface 2a is θ, the tensile load Ft acting on the liquid crystal fiber 10 is expressed by the following equation. Ft = F · sin θ By substituting the above formulas into this formula, the following formula is obtained. Ft = 2π ・ η ・ Vo ・ L ²・ cos ² θ ・ sin ² θ / [h ・ log (7.4 / Re)] ...

When the tensile load Ft exceeds the tensile strength σ _T of the liquid crystal fiber 10, the liquid crystal fiber 10 breaks. Therefore, the limit condition for the liquid crystal fiber 10 to break is given by the following equation. _{Ft = σ T · π · D} 2/4 ... Here, the a θ example 80 degrees, is an expression of the above equation, by organizing the L, the critical length L when the liquid crystal fiber 10 is cut As a given expression, the following expression is obtained. L = √ {[σ _T・ h ・ D ²・ log (7.4 / Re)] / [0.2376 ・ η ・ Vo]} ...

From the above formula, if the diameter D and the tensile strength σ _{T of} the liquid crystal fiber 10 are the same, and the physical conditions such as the rotation speed of the rotating screw at the time of plasticizing and melting are the same, the liquid crystal fiber is obtained. The limit length L when 10 is cut is
Liquid crystal fiber tensile strength (σ _T ) matrix resin viscosity
It can be seen that it largely depends on the value of the square root of the ratio (σ _T / η) to (η). That is, in the liquid crystal resin composite, the tensile strength σ _T of the liquid crystal fiber 10 and the viscosity η of the matrix resin both change with temperature, so the ratio of the two is important, and the value of the square root of the above (σ _T / η) By performing the plasticization in the temperature region where the temperature becomes large, the breakage of the liquid crystal fiber 10 can be suppressed as much as possible.

Therefore, based on the above analysis results, the change in the square root value of (σ _T / η) with temperature was investigated for a predetermined liquid crystal resin composite molding material, and this material was also used. A test was conducted on the molded product obtained by molding to examine the change in its mechanical properties with temperature. In this example, the following materials were used as the thermoplastic matrix resin and the thermoplastic liquid crystal resin when preparing the molding material (pellets) for the liquid crystal resin composite. (a) Thermoplastic liquid crystal resin-Material name: wholly aromatic polyester resin-Product name: Vectra A950 (manufactured by Polyplastics) -Liquid crystal transition temperature: 280 ° C (b) Thermoplastic matrix resin-Material name: Polystyrene resin ( (PS resin) -Brand name: SBRIGHT 9M (manufactured by Showa Denko KK) -Minimum moldable temperature: 160 ° C (molding is extremely difficult at temperatures below 160 ° C, and molding may not be possible depending on the shape at 160-170 ° C) is there)

FIG. 3 shows the thermoplastic matrix resin (P
The change in viscosity η of S resin) with temperature is shown in FIG. 4, and the change in the tensile strength σ _T of the thermoplastic liquid crystal resin Vectra A950 with temperature is shown in FIG. The following device was used to measure the viscosity η of the matrix resin. Viscosity measuring device: Model Capillograph 1C manufactured by Toyo Seiki Seisakusho Co., Ltd. Further, the square root of the ratio (σ _T / η) of the tensile strength σ _T of the liquid crystal fiber to the viscosity η of the matrix resin √ (σ _T / η).
FIG. 5 shows the change in the value of γ with temperature.

The above molding material was prepared as follows. That is, 60 parts by weight of a liquid crystal resin (that is, a liquid crystal resin content of 60% by weight) was mixed with 40 parts by weight of the matrix resin, and the mixture was extruded by a twin-screw extruder to form a strand-shaped liquid crystal resin composite. Was molded, and this was cut with a so-called pelletizer to a predetermined length (for example, 6 mm) to obtain pellets. The equipment and preparation conditions used for the preparation of the pellets were as follows.・ Twin-screw extruder: Model BT-30-S2-36-L manufactured by Plastic Engineering Laboratory Co., Ltd. ・ Shear rate at die: 1500 / sec. ・ Screw speed: 150 rpm ・ Stretching ratio: 3

The pellets prepared as described above are put into a plasticizing and melting apparatus equipped with a rotating screw to melt only the matrix resin of each pellet,
Molding was performed by injecting into a predetermined molding die, and a test piece was sampled from the obtained molded product, and its mechanical characteristics (impact resistance) were examined. FIG. 2 shows an outline of the overall configuration of the plasticizing and melting apparatus. As shown in this figure, a plasticizing and melting apparatus 1 according to the present embodiment has a cylindrical main body 2, a nozzle head 3 fixed to the end of the main body 2, and a housing 2 housed in the main body 2. The rotary screw 5 and a cylinder device (injection cylinder: not shown) for driving the screw 5 are main components, and the side surface of the main body 2 has a pellet PT as a molding material in the main body 2. A hopper 6 for throwing in is attached.

The molding material (pellet PT) in which the thermoplastic liquid crystal resin having a liquid crystal transition temperature higher than the minimum moldable temperature of the thermoplastic matrix resin is present in the thermoplastic matrix resin (pellet PT) is used as the hopper 6 mentioned above. When charged into the body 2 from the inside, the charged pellets PT internally generate heat due to the action of the shearing force accompanying the rotation of the screw 5, and mainly due to this heat, the temperature of the molding material can be the minimum molding of the matrix resin. The temperature is raised to a temperature within the range above the liquid crystal transition temperature of the liquid crystal resin (in the mold window), and only the matrix resin is in a molten state, and molding is performed while maintaining the fibrous state of the liquid crystal resin. You can The inner wall surface 2a of the main body portion 2 constitutes the barrel wall surface in the model shown in FIG. Further, although not specifically shown, an external heater is provided on the outer peripheral side of the main body 2 mainly to keep the resin material fluidized in the main body 2 warm. The external heater may be embedded in the side wall of the main body 2.

A mold device 9 composed of a pair of molds 9A and 9B is mounted on the tip side of the nozzle head 3, and the molten resin injected from the nozzle hole 3a is stored in the mold device 9. The molding space 9d is filled through the runner portion 9c to mold a predetermined molded product. The apparatus and molding conditions used for this injection molding are shown below.・ Molding machine: Model IS-220EN-5Y (Toshiba Machinery
(Made by Co., Ltd.) ・ Screw speed: 80 rpm ・ Back pressure: 2 kgf / cm ²・ Injection pressure: 2460 kg / in ² (99% of maximum injection pressure) ・ Injection speed: 10 mm / sec. (Screw moving speed) ・ Mold temperature: 50 ℃

Under the above conditions, injection molding was repeated by changing the set temperature of the barrel within a predetermined range, and test pieces at each temperature were sampled. Then, an Izod impact test was performed using each test piece. In addition, this impact test was performed on the temperature condition of 23 degreeC based on ASTMD256. The test results are shown in FIG. By comparing the graph of FIG. 6 with the graph of FIG. 5, the square root of the ratio (σ _T / η) of the tensile strength σ _T of the liquid crystal fiber to the viscosity η of the matrix resin √ (σ _T / η) It was found that the impact value of the obtained molded product is higher in the temperature region where the value of is higher than the other temperature regions. It is considered that this is because breakage of the liquid crystal fibers is effectively suppressed by performing plasticization in a temperature range where the square root √ (σ _T / η) value is high.

According to the above-mentioned test, when Vectra A950 is used as the thermoplastic liquid crystal resin and the matrix resin is PS resin, the plasticizing temperature is 160 to 210.
It was found that the temperature should be set in the temperature range of ° C. The lower limit of the temperature is set to 160 ° C. because the molding becomes extremely difficult below this temperature, and the upper limit of the temperature is set to 210 ° C.
The reason is that the impact resistance sharply decreases when the temperature is exceeded. In order to secure better moldability, the plasticizing temperature is more preferably 170 to 210 ° C. This is because molding may not be possible depending on the shape in the temperature range of 160 to 170 ° C. Further, in order to secure the highest level of impact resistance, it is more preferable to set the plasticizing temperature to 180 to 200 ° C.

Next, as the thermoplastic liquid crystal resin, the above-mentioned Vectra A950 was used as in the above-mentioned embodiment, and the same test was conducted by substituting the thermoplastic matrix resin with various other resins different from those in the above-mentioned embodiment. . As a result, the square root of the ratio (σ _T / η) of the tensile strength σ _T of the liquid crystal fibers to the viscosity η of the matrix resin √
In the temperature range where the value of (σ _T / η) is higher than the others, the plasticization in this area effectively suppresses the breakage of the liquid crystal fiber, and the impact value of the obtained molded product is Turned out to be higher than. Another embodiment of the present invention will be described below. The apparatus and conditions such as pellet preparation, matrix resin viscosity measurement, injection molding and impact test in these other examples were the same as those in the above-mentioned examples.

(1) When a polyamide 6 resin (PA6 resin) is used as the thermoplastic matrix resin In this test, PA6 shown below is used as the matrix resin.
Resin was used.・ Product name: 1013 B (manufactured by Ube Industries, Ltd.) ・ Minimum moldable temperature: about 230 ° C. (melting point: 223 ° C.) The test results are shown in FIGS. 7 and 8. From this test result,
It has been found that when the matrix resin is PA6 resin, the plasticizing temperature may be set in the temperature range of 230 to 245 ° C. The lower limit of the temperature is set to 230 ° C because the molding becomes extremely difficult below this temperature, and the upper limit of the temperature is set to 245 ° C because the impact resistance becomes low when the temperature is exceeded. Is. In addition, in order to secure better impact resistance, the above plasticization temperature is set to 230 to 240.
More preferably, the temperature is set to ° C. Further, in order to obtain the highest level of impact resistance, the above plasticization temperature should be 230-2.
More preferably, it is set to 35 ° C.

(2) When a polybutylene terephthalate resin (PBT resin) is used as the thermoplastic matrix resin In this test, PBT shown below is used as the matrix resin.
Resin was used.・ Product name: 1401-X07 (manufactured by Toray Industries, Inc.) ・ Minimum moldable temperature: about 230 ° C. (melting point: 228 ° C.) The test results are shown in FIGS. 9 and 10. From this test result, it was found that when the matrix resin is PBT resin, the plasticizing temperature should be set in the temperature range of 230 to 245 ° C. The lower limit of the temperature is set to 230 ° C. because molding becomes extremely difficult below this temperature.
The upper limit of the temperature is set to 245 ° C., because if it exceeds this temperature, the impact resistance becomes low. In addition, in order to secure better impact resistance, the above plasticizing temperature is set to 230 to 2
More preferably, the temperature is 40 ° C. Further, in order to obtain the highest level of impact resistance, the above plasticization temperature should be 230
More preferably, it is set to ˜235 ° C.

(3) When a polypropylene resin (PP resin) is used as the thermoplastic matrix resin In this test, the PP resin shown below was used as the matrix resin.・ Product name: Noblen H501 (Sumitomo Chemical Co., Ltd.)
Manufacture) ・ Minimum moldable temperature: 185 ° C. The test results are shown in FIGS. 11 and 12. From this test result, it was found that when the matrix resin is the PP resin, the plasticizing temperature should be set in the temperature range of 185 to 210 ° C. The lower limit of temperature is set to 185 ° C., because molding becomes extremely difficult below this temperature, and the upper limit of temperature is set to 210 ° C., since impact resistance decreases below this temperature. Is. In order to secure better impact resistance, the plasticizing temperature is set to 185 to 20.
More preferably, the temperature is 0 ° C. Further, in order to obtain the highest level of impact resistance, the above plasticization temperature is 185-185.
It is more preferable to set it to 190 ° C.

(4) When acrylonitrile-butadiene-styrene resin (ABS resin) is used as the thermoplastic matrix resin In this test, the ABS resin shown below is used as the matrix resin.
Resin was used. -Product name: SXD220 (manufactured by Sumitomo Dow Co., Ltd.)-Minimum moldable temperature: 180 ° C The test results are shown in Figs. From this test result, it was found that when the matrix resin is ABS resin, the plasticizing temperature should be set in the temperature range of 180 to 230 ° C. The lower limit of the temperature is set to 180 ° C., because it is extremely difficult to mold below this temperature.
The upper limit of the temperature is set to 230 ° C. because the impact resistance becomes low when the temperature is exceeded. In order to secure better impact resistance, the above plasticization temperature is set to 180 to 2
More preferably, the temperature is 20 ° C. Further, in order to obtain the highest level of impact resistance, the above plasticization temperature is set to 190
More preferably, the temperature is set to 210 ° C.

(5) When a modified polyphenylene ether resin (m-PPE resin) is used as the thermoplastic matrix resin: In this test, m-P shown below was used as the matrix resin.
PE resin was used.・ Product name: Noril SE90 (Japan GE Plastics
・ Minimum moldable temperature: 180 ° C. The test results are shown in FIGS. 15 and 16. From this test result, it was found that when the matrix resin is m-PPE resin, the plasticizing temperature should be set in the temperature range of 180 to 230 ° C. The lower limit of the temperature is set to 180 ° C. because the molding becomes extremely difficult below this temperature, and the upper limit of the temperature is set to 230 ° C. because the impact resistance is lowered above this temperature. Is. In order to secure better impact resistance, the plasticizing temperature is set to 180
More preferably, it is set to 220 ° C. Further, in order to obtain the highest level of impact resistance, the above plasticization temperature should be 1
More preferably, the temperature is set to 90 to 210 ° C.

In each of the above examples, the plasticizing temperature is set in a suitable temperature range in order to suppress breakage of the liquid crystal fibers when the molding material is plasticized and melted. The molding material after the matrix resin has been plasticized and melted may be molded by holding it in a temperature region other than the above-mentioned plasticization temperature range for the purpose of, for example, improving moldability. is there. That is, as shown in FIG. 17, the plasticizing and melting material which has already been plasticized and melted is temporarily provided between the end of the rotary screw 15 and the injection nozzle hole 13a on the downstream side of the end of the rotary screw 15. The matrix resin is plasticized by providing a retention section Sm for retaining the retention section, and disposing, for example, a heater on the main body wall section 12 forming the outer periphery of the retention section Sm or outside the main body wall section 12. The molding material after being melted can be heated to a desired molding temperature. By using such a plasticizing and melting device 11, it becomes possible to carry out molding while keeping the material for molding at an optimum temperature while effectively suppressing breakage of the liquid crystal fibers when plasticizing and melting the matrix resin.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a model of a liquid crystal fiber which is subjected to a shearing action in a matrix resin at the initial stage of plasticization.

FIG. 2 is a vertical cross-sectional explanatory view schematically showing an overall configuration of a plasticizing and melting apparatus according to an example of the present invention.

FIG. 3 is a graph showing changes in viscosity η of a thermoplastic matrix resin (PS resin) with temperature.

FIG. 4 is a graph showing changes in the tensile strength σ _T of the thermoplastic liquid crystal resin Vectra A950 with temperature.

FIG. 5 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is PS resin.

FIG. 6 is a graph showing changes in impact value with temperature when the matrix resin is PS resin.

FIG. 7 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is PA6 resin.

FIG. 8 is a graph showing changes in impact value with temperature when the matrix resin is PA6 resin.

FIG. 9 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is PBT resin.

FIG. 10 is a graph showing changes in impact value with temperature when the matrix resin is PBT resin.

FIG. 11 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is a PP resin.

FIG. 12 is a graph showing changes in impact value with temperature when the matrix resin is PP resin.

FIG. 13 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is an ABS resin.

FIG. 14 is a graph showing changes in impact value with temperature when the matrix resin is ABS resin.

FIG. 15 is a graph showing changes in the value of √ (σ _T / η) with temperature when the matrix resin is m-PPE resin.

FIG. 16 is a graph showing changes in impact value with temperature when the matrix resin is m-PPE resin.

FIG. 17 is an explanatory longitudinal sectional view schematically showing the overall configuration of the plasticizing and melting apparatus according to the example of the present invention.

[Explanation of symbols]

 1, 11 ... Plasticizing and melting device 5,15 ... Rotating screw PT ... Pellet (molding material)

Claims (7)

[Claims] 1. A molding material comprising a thermoplastic matrix resin in which a thermoplastic liquid crystal resin having a liquid crystal transition temperature higher than the minimum moldable temperature of the thermoplastic matrix resin is composited into a fibrous state, and a rotary screw type By kneading with the plasticizing and melting apparatus of, the thermoplastic matrix resin is plasticized only at a temperature not lower than the minimum moldability of the thermoplastic matrix resin and lower than the liquid crystal transition temperature of the thermoplastic liquid crystal resin. In the method for molding a liquid crystal resin composite which is formed by melting and melting, the plasticization temperature is a ratio of the tensile strength (σ _T ) of the liquid crystal fibers to the viscosity (η) of the thermoplastic matrix resin (σ _T /
A method for molding a liquid crystal resin composite, characterized in that the square root value of η) is set in a temperature range where it is higher than the others. 2. The thermoplastic matrix resin is a polystyrene resin, and the plasticizing temperature is 160 to 210 ° C.
The method for molding a liquid crystal resin composite according to claim 1, wherein 3. The thermoplastic matrix resin is a polyamide 6 resin, and the plasticizing temperature is 230 to 245 ° C.
The method for molding a liquid crystal resin composite according to claim 1, wherein 4. The thermoplastic matrix resin is a polybutylene terephthalate resin, and the plasticizing temperature is 2
It is 30-245 degreeC, The molding method of the liquid crystal resin composite of Claim 1 characterized by the above-mentioned. 5. The thermoplastic matrix resin is a polypropylene resin, and the plasticizing temperature is 185 to 210.
The method for molding a liquid crystal resin composite according to claim 1, wherein the temperature is at 0 ° C. 6. The method for molding a liquid crystal resin composite according to claim 1, wherein the thermoplastic matrix resin is an acrylonitrile-butadiene-styrene resin and the plasticizing temperature is 180 to 230 ° C. 7. The thermoplastic matrix resin is a modified polyphenylene ether resin, and the plasticizing temperature is 1
The method for molding a liquid crystal resin composite according to claim 1, wherein the temperature is 80 to 230 ° C.