JPH06262690A - Stock and method for molding liquid crystal resin composite - Google Patents

Abstract

PURPOSE:To effectively preclude liquid crystal fiber from rupturing in a molding process by forming a three-component molding stock with two kinds of matrix resin having different melting points and liquid crystal resin, and also forming a sub-composite with matrix resin not susceptible to melting at a molding temperature and liquid crystal fiber. CONSTITUTION:In the process, there id prepared a molding raw material P that contains thermoplastic liquid crystal resin L, a first thermoplastic matrix resin M1 having a lower melting point than the liquid crystal transition temperature of the liquid crystal resin, and a second thermoplastic resin M2 having a higher melting point than that of the first matrix resin, and has a sub- composite S formed of liquid crystal resin dispersed in a fibrous condition in the second matrix resin, and dispersed in the first matrix resin. This is molded at a lower temperature than the liquid crystal transition temperature, a lower temperature than a melting temperature of the second matrix resin, and at a higher temperature than the melting point of the first matrix resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material and a molding method for a liquid crystal resin composite, and more particularly to a molding material for a liquid crystal resin composite in which a thermoplastic liquid crystal resin is dispersed in a matrix resin in a fibrous state. It relates to a molding method.

[0002]

2. Description of the Related Art Conventionally, as a material for 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. Among them, it is generally well known that, for example, the liquid crystal resin having a predetermined length is present in a fibrous state. Also,
As a molding method using such a molding material (pellet),
For example, as disclosed in Japanese Patent Application Laid-Open No. 1-301749, a method of kneading the pellets with a plasticizing melting device such as a rotary screw type to melt only the matrix resin and molding with, for example, an injection molding machine. Is known. In this molding method, the pellets internally generate heat due to the action of shearing force accompanying the rotation of the screw, and mainly due to this heat, the temperature of the pellets is the minimum moldable temperature of the matrix resin or more and less than the liquid crystal transition temperature of the liquid crystal resin. When the temperature is raised to the range, 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, the thermoplastic liquid crystal resin is required to be stretched at a stretch ratio of a predetermined value or more in order to obtain mechanical characteristics of a certain level or more, and therefore, compared with other fiber reinforced materials such as glass fiber and carbon fiber. Therefore, it is difficult to obtain a fiber having a large wire diameter in a fiberized state having predetermined physical properties,
Therefore, there is a problem that the fiber is likely to break during the molding process. Therefore, for example, when the above-mentioned molding method is adopted, the liquid crystal resin inside the pellets is cut by the action of shearing force accompanying the rotation of the screw, and the length cannot be maintained at the predetermined length aligned before kneading. However, there is a drawback that the mechanical characteristics (that is, strength and rigidity) of the molded resin molded product are adversely affected. Further, even when another molding method such as a press molding method is adopted, similarly, there is a problem of fiber breakage during the molding process.

Regarding this problem, it is not particularly conscious of using a thermoplastic liquid crystal resin as a fiber reinforcing material, but as a means for suppressing the breakage of the fiber in the plasticizing and melting step, for example, in Japanese Patent Laid-Open No. 1-286824. , A pellet of a first thermoplastic resin containing fibers and a pellet of a second thermoplastic resin having a flow starting temperature or a melting temperature lower than that of the resin are mixed in a plastic state with a rotary screw. Disclosed is a method for producing a fiber-reinforced thermoplastic resin in which the second thermoplastic resin is plasticized and melted before the first thermoplastic resin is plasticized and melted by dry blending with a plasticizing and melting device. Has been done. According to this method, the first thermoplastic resin containing the fibers is in a state of being included in the second thermoplastic resin already plasticized and melted before the resin is plasticized and melted,
The shearing force is prevented from directly acting on the fibers contained in the first thermoplastic resin, and the breakage of the fibers in the plasticizing and melting step is suppressed to some extent. In this case, the pellets of the first thermoplastic resin are mainly
It is plasticized and melted by the heat transmitted from the previously melted second thermoplastic resin.

[0005]

As described above, when a thermoplastic liquid crystal resin is used as a reinforcing fiber material, it is difficult to obtain a fiber having a large wire diameter, that is, the fiber becomes thin. In the above, the fiber is likely to break. Therefore, even if the liquid crystal fiber itself cannot be thickened, the liquid crystal fibers are bundled to some extent and aggregated, and an external force (for example, shearing force in the molding process) is used as a unit of this aggregated body
If it is possible to achieve this, it is considered that a great effect can be brought about in preventing breakage of the liquid crystal fiber.

By the way, the applicant of the present application has proposed that a temperature at which all three components of two types of thermoplastic matrix resin and thermoplastic liquid crystal resin having different minimum moldable temperatures (melting points in the case of crystalline materials) are in a molten state. In the case of extrusion molding, depending on the compounding ratio of each component, the liquid crystal resin is dispersed in a fibrous state in the matrix resin of the higher minimum moldable temperature, which is a kind of composite (that is, the composite as a whole). It has been found that smaller units formed therein have a microstructure dispersed therein in a matrix resin having a lower minimum moldable temperature. FIG. 1 is an explanatory diagram schematically showing an image of a cross-sectional structure of a three-component liquid crystal resin composite having such a microstructure. Second with the highest minimum moldable temperature
The sub-composite S in which the liquid crystal resin L is dispersed in the matrix resin M2 in a fibrous state is dispersed in the first matrix resin M1 having a lower minimum moldable temperature to form a liquid crystal resin as a molding material. A complex P is constructed.

According to the present invention, a liquid crystal fiber forms a subcomposite with one matrix resin in the above three-component system, and a microstructure in which the subcomposite is dispersed in another matrix resin can be obtained. In consideration of the above, by forming the sub-composite with a matrix resin and liquid crystal fibers that do not melt at the molding temperature,
An object of the present invention is to provide a material for molding a liquid crystal resin composite and a molding method capable of effectively preventing breakage of liquid crystal fibers in a molding step.

[0008]

Therefore, the material for molding the liquid crystal resin composite according to the first invention of the present application is a thermoplastic liquid crystal resin and a minimum moldable temperature lower than the liquid crystal transition temperature of the liquid crystal resin. And a second thermoplastic matrix resin having a minimum moldable temperature higher than that of the first matrix resin, wherein the liquid crystal resin is a fiber in the second matrix resin. It is characterized in that the subcomposite dispersed in this state and comprising the liquid crystal resin and the second matrix resin is dispersed in the first matrix resin.

A second invention of the present application is the material for molding a liquid crystal resin composite according to the first invention, wherein the second thermoplastic matrix resin is a polyamide resin. is there. As the polyamide (PA) resin, for example, nylon 6 resin (PA6), nylon 66 resin (PA66), nylon 46 resin (PA46), aromatic PA or the like can be applied. In this case, the first
As the thermoplastic matrix resin of, a polypropylene resin, a polyethylene resin, a polystyrene resin, a modified polyphenylene ether resin, an ABS (acrylic-butadiene-styrene copolymer) resin, or the like can be applied as the thermoplastic resin other than the polyamide resin. .

Further, in a third invention of the present application, in the material for molding a liquid crystal resin composite according to the second invention, the weight ratio of the thermoplastic liquid crystal resin in the sub composite exceeds 50%, In addition, the weight ratio of the sub-composite in the entire molding material is 3% or more and 50% or less. The second reason is that the weight ratio of the liquid crystal resin in the sub-composite exceeds 50%.
This is because when the thermoplastic matrix resin is a polyamide resin, the fibrous state of the liquid crystal resin cannot be stably maintained at 50% or less. Further, the reason why the weight ratio of the sub-composite in the whole molding material is set to 3% or more and 50% or less is that if it is less than 3%, the reinforcing effect by the liquid crystal fiber is obtained even from the experience of the two-component system. On the other hand, if it exceeds 50%, the improvement of the reinforcing effect due to the three-component molding material cannot be stably obtained.

Further, a fourth invention of the present application is the molding material of the liquid crystal resin composite according to the first invention,
The second thermoplastic matrix resin is a polyester resin. As the polyester resin, for example, polybutylene terephthalate resin, polyethylene terephthalate resin, polyarylate resin, polycarbonate resin, or the like can be applied. In this case, as the first thermoplastic matrix resin, as the thermoplastic resin other than the polyester resin, polypropylene resin, polyethylene resin, polystyrene resin,
Modified polyphenylene ether resin, ABS (acrylic-butadiene-styrene copolymer) resin, etc. can be applied.

Further, a fifth invention of the present application is the molding material for the liquid crystal resin composite according to the fourth invention,
The weight ratio of the thermoplastic liquid crystal resin in the sub-composite is 2% or more, and the weight ratio of the sub-composite in the entire molding material is 3% or more and less than 60%. It is what The weight ratio of the thermoplastic liquid crystal resin in the sub-composite is set to 2% or more, because when the second thermoplastic matrix resin is a polyester resin, the fiberization state of the liquid crystal resin is stable when it is less than 2%. Because it cannot be maintained. In addition, the weight ratio of the sub-composite in the entire molding material is 3% or more and 6
Below 0%, if less than 3%, the reinforcing effect by the liquid crystal fiber cannot be obtained even from experience with a two-component system, while if over 60%, the molding material is made into a three-component system. This is because the improvement in the reinforcing effect due to the above cannot be stably obtained.

The method of molding a liquid crystal resin composite according to the sixth invention of the present application is the first method which comprises a thermoplastic liquid crystal resin and a minimum moldable temperature lower than the liquid crystal transition temperature of the liquid crystal resin.
And a second thermoplastic matrix resin having a minimum moldable temperature higher than that of the first matrix resin at a temperature higher than the liquid crystal transition temperature and the minimum moldable temperature of the second matrix resin. In, the material is prepared by extrusion molding, and the prepared material is less than the liquid crystal transition temperature and less than the minimum moldable temperature of the second matrix resin and the minimum moldable temperature of the first matrix resin. It is characterized by being molded at the above temperature.

[0014]

According to the material for molding a liquid crystal resin composite according to the present invention, the liquid crystal resin is dispersed in the second matrix resin in a fibrous state to form a sub composite. The liquid crystal fibers in the sub-composite are joined and reinforced by the second matrix resin, and this serves as an aggregate of one unit. In other words, it serves as a reinforcing material in a state where the apparent thickness becomes thick. Will be fulfilled. Since such a sub-composite is formed by being dispersed in the first matrix resin, it is lower than the lower one of the liquid crystal transition temperature of the liquid crystal resin and the minimum moldable temperature of the second matrix resin. By performing molding at a low temperature and in a temperature range that is equal to or higher than the minimum moldable temperature of the first matrix resin, it is possible to effectively prevent breakage of the liquid crystal fibers in the molding process.

In this case, a polyamide resin or a polyester resin can be used as the second thermoplastic matrix resin, and each resin is defined in claim 3 (polyamide resin) or claim 5 (polyester resin). As described, by setting the weight ratio of the liquid crystal resin in the sub-composite and the weight ratio of the sub-composite in the entire molding material, the fiberized state of the liquid crystal resin is stably maintained, and the molding The reinforcing effect can be improved by forming the sub-composite as a three-component system material in the interior thereof.

Further, according to the method for molding a liquid crystal resin composite according to the present invention, the liquid crystal resin, the first matrix resin and the second matrix resin are extruded at a temperature at which all three components are in a molten state. To prepare a molding material, and thereby a sub-composite formed by dispersing the liquid crystal resin in a fiber state in the second matrix resin is dispersed in the first matrix resin. You can get the material. The molding material is kept at a temperature lower than the liquid crystal transition temperature of the liquid crystal resin or the minimum moldable temperature of the second matrix resin, whichever is lower, and at a temperature higher than the minimum moldable temperature of the first matrix resin. Since the molding was carried out, the liquid crystal fibers in the sub-composite were joined and reinforced by the second matrix resin, and this was an aggregate of one unit, in other words, the apparent thickness became thicker. In this state, it plays a role of a reinforcing material, and can effectively prevent breakage of the liquid crystal fibers in the molding process.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. The first embodiment uses a polyamide resin as the second thermoplastic matrix resin. The resin materials used as the first and second thermoplastic matrix resins and the thermoplastic liquid crystal resin in preparing the material for molding the liquid crystal resin composite according to this example are shown below. First thermoplastic matrix resin-Material name: Polystyrene resin (PS resin) -Product name: Dialex HF-77 (manufactured by Mitsubishi Kasei Polytex Co., Ltd.)-Minimum moldable temperature: 170 ° C Second thermoplastic matrix resin・ Material name: Nylon 46 resin (PA46 resin) ・ Brand name: Grade TS300 (manufactured by Nippon Synthetic Rubber Co., Ltd.) ・ Minimum moldable temperature: 290 ℃ thermoplastic liquid crystal resin ・ Material name: Aromatic polyester resin ・ Brand name: Vectra A950 (manufactured by Polyplastics Co., Ltd.)-Liquid crystal transition temperature: 280 ° C

The above matrix resins and liquid crystal resins were dry blended at the compounding ratios shown in Table 1, extruded by a biaxial extruder, and further stretched by a stretching machine to obtain a strand-shaped liquid crystal resin composite. Prepared. Then, the strand-shaped composite body was cut into pieces each having a length of 3 mm to obtain pellet-shaped molding materials. In this example, the compounding ratio of each material resin was set so that the weight ratio of the liquid crystal resin in the entire molding material was 30%. This also applies to other embodiments described later. In Table 1 above,
Reference symbol M1 is the first thermoplastic matrix resin, and reference symbol M is
Reference numeral 2 represents a second thermoplastic matrix, and reference numeral L represents a thermoplastic liquid crystal resin.

[0019]

[Table 1]

The apparatus and preparation conditions used for the preparation of the pellet-shaped molding material are shown below. Pellet preparation equipment and preparation conditions ・ Twin-screw extruder: Model ST-30-S2-36L Plastic Engineering Laboratory, screw diameter = 30mm ・ Stretching machine: In-house ・ Extrusion conditions: Resin temperature = 300 ° C, screw Rotation speed = 75 rpm, shear rate = 1700 / sec.

Next, the pellets are extruded by a melt viscosity measuring device as a kind of extruder,
A rod-shaped molded product was obtained. The equipment and molding conditions used for this extrusion molding are shown below. Equipment used for extrusion molding and molding conditions ・ Device: Melt viscosity measuring device (Product name: Capillograph 1
C) Toyo Seiki Seisakusho Co., Ltd., barrel diameter = 9.55mm ・ Molding conditions: resin temperature = 190 ℃, die diameter = 0.5mm,
Extrusion speed = 2 mm / min

The resin temperature in the extrusion molding is lower than both the liquid crystal transition temperature of the liquid crystal resin (280 ° C.) and the minimum moldable temperature of the second matrix resin (290 ° C.), and the first temperature. It is set as a temperature equal to or higher than the minimum moldable temperature (170 ° C.) of the matrix resin (1). The outline of the main part of the melt viscosity measuring device is shown in FIG. As shown in this figure, a pellet 1 is placed in a cylinder 2 in which a heater 4 is embedded, heated by the heater 4 until the pellet 1 reaches the resin temperature (190 ° C.), and then a piston 6 is lowered to move the material. By extruding the resin through the extrusion hole, the rod-shaped molded product 10 can be molded.

A test for measuring the tensile strength of the molded product obtained as described above was conducted. The test results were as shown in Table 1. The tensile strength test data is shown by a broken line in the graph of FIG.
As is clear from the test results, when a polyamide resin (PA46 resin) was used as the second thermoplastic matrix resin, L / (L + M2) exceeded 50% and (L + M2)
When M2) / (L + M2 + M1) is 3% or more and 50% or less, in the case of a two-component system (the content of M2 is 0 wt%
In the case of), the tensile strength is improved.

Next, a second embodiment of the present invention will be described. The second embodiment uses a polyester resin as the second thermoplastic matrix resin. In preparing the molding material of the liquid crystal resin composite according to this example,
The resin materials used as the first and second thermoplastic matrix resins and the thermoplastic liquid crystal resin are shown below. First thermoplastic matrix resin-Material name: Polystyrene resin (PS resin) -Product name: Dialex HF-77 (manufactured by Mitsubishi Kasei Polytex Co., Ltd.)-Minimum moldable temperature: 170 ° C Second thermoplastic matrix resin・ Material name: Polyethylene terephthalate resin (PET resin) ・ Product name: Unipet RT560CN (manufactured by Nippon Unipet Co.) ・ Minimum moldable temperature: 255 ℃ Thermoplastic liquid crystal resin ・ Material name: Aromatic polyester resin ・ Product name: Vectra A950 (manufactured by Polyplastics Co., Ltd.)-Liquid crystal transition temperature: 280 ° C

The compounding ratio of each matrix resin and liquid crystal resin is as shown in Table 2. A pellet-shaped molding material was prepared in the same manner as in the case of the first embodiment by using the resin material of each compounding ratio, and extrusion molding was performed using this, and the tensile strength of the obtained molded product was measured. The test was done.
In this case, the apparatus and conditions for pellet preparation, and the apparatus and molding conditions used for extrusion molding are the same as in the first embodiment. The test results were as shown in Table 2. The tensile strength test data is shown by a solid polygonal line in the graph of FIG.
As is clear from the test results, when polyester resin (PET resin) is used as the second thermoplastic matrix resin, L / (L + M2) is 2% or more, and (L + M
In the range of 2) / (L + M2 + M1) of 3% or more and less than 60%, the tensile strength is improved as compared with the case of the two-component system (when the content of M2 is 0% by weight).

[0026]

[Table 2]

Next, a third embodiment of the present invention will be described. The third embodiment differs from the second embodiment in that the first thermoplastic matrix resin material is changed. The resin materials used as the first and second thermoplastic matrix resins and the thermoplastic liquid crystal resin in preparing the material for molding the liquid crystal resin composite according to this example are shown below. 1st thermoplastic matrix resin-Material name: polypropylene resin-Product name: Noblen D501 (Sumitomo Chemical Co., Ltd.)-Minimum moldable temperature: 155 ° C 2nd thermoplastic matrix resin-Material name: Polyethylene terephthalate resin ( (PET resin) ・ Product name: Unipet RT560CN (manufactured by Nippon Unipet Co.) ・ Minimum moldable temperature: 255 ℃ Thermoplastic liquid crystal resin ・ Material name: Aromatic polyester resin ・ Product name: Vectra A950 (manufactured by Polyplastics Co., Ltd.) ) ・ Liquid crystal transition temperature: 280 ℃

The compounding ratios of the above matrix resins and liquid crystal resins are as shown in Table 3. A pellet-shaped molding material was prepared in the same manner as in the case of the first and second examples using the resin material having each compounding ratio, and extrusion molding was performed using this, and the resulting molded product had a tensile strength. A test was performed to measure the height. In this case, the apparatus and conditions for pellet preparation, and the apparatus and molding conditions used for extrusion molding are the same as those in the first and second embodiments. The test results were as shown in Table 3. Further, this tensile strength test data is shown by a solid line in the graph of FIG. As is clear from the test results, when a polyester resin (PET resin) is used as the second thermoplastic matrix resin, L / (L + M2) remains unchanged even if the resin material of the first thermoplastic matrix resin is changed. Two
% Or more and (L + M2) / (L + M2 + M1) is 3%
In the above range of less than 60%, in the case of two component system (M
The tensile strength is improved as compared with the case where the content of 2 is 0% by weight). In addition, (L + M2) / (L + M2 + M1) is 70%
In the range exceeding, even if the force applied to the piston 6 (see FIG. 2) of the molding apparatus during extrusion molding is increased to the maximum limit,
The rod-shaped product could not be extruded.

[0029]

[Table 3]

5 to 8 are explanatory views schematically showing a simplified micrograph of a microstructure of each strand of the liquid crystal resin composite according to this example. The above micrograph is a photograph of the microstructure of each sample obtained by thinly slicing the strand, after dissolving the first matrix resin with a solvent. An example of the case where the second thermoplastic matrix resin is not compounded is shown in FIG. 5, an example of the case where the compounding ratio is relatively low (5% by weight) is shown in FIG. 6, and an example where the compounding ratio is relatively high (20% by weight). 7), and (L + M2) / (L + M2 + M1),
That is, FIG. 8 shows an example in which the weight ratio of the sub-composite in the entire strand is too high (more than 70%).
As is clear from a comparison between these figures and the test data in Table 3 above, the sub-composite formed by the liquid crystal fibers dispersed in the second matrix resin M2 was dispersed in the first matrix resin. The tensile strength is highest when it has a microstructure (when the content of M2 is 20% by weight).

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an image of a cross-sectional structure of a three-component liquid crystal resin composite in which a sub-composite is formed.

FIG. 2 is a cross-sectional explanatory view showing a main part of an extrusion device according to an embodiment of the present invention.

FIG. 3 is a graph showing measured data of tensile strength of molded products of liquid crystal resin composites according to the first and second examples of the present invention.

FIG. 4 is a graph showing measurement data of tensile strength of a molded product of a liquid crystal resin composite according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram schematically showing an example of a microstructure of a cross section of the liquid crystal resin composite according to the third embodiment.

FIG. 6 is an explanatory view schematically showing an example of a microstructure of a cross section of the liquid crystal resin composite according to the third embodiment.

FIG. 7 is an explanatory view schematically showing an example of a microstructure of a cross section of the liquid crystal resin composite according to the third embodiment.

FIG. 8 is an explanatory view schematically showing an example of a microstructure of a cross section of the liquid crystal resin composite according to the third embodiment.

[Explanation of symbols]

 L ... Thermoplastic liquid crystal resin M1 ... First thermoplastic matrix resin M2 ... Second thermoplastic matrix resin P ... Liquid crystal resin composite (molding material) S ... Sub composite

Claims (6)

[Claims] 1. A thermoplastic liquid crystal resin, a first thermoplastic matrix resin having a minimum moldable temperature lower than a liquid crystal transition temperature of the liquid crystal resin, and a minimum moldable temperature higher than the first matrix resin. A subcomposite containing a second thermoplastic matrix resin, wherein the liquid crystal resin is dispersed in a fiber state in the second matrix resin, and the sub-composite of the liquid crystal resin and the second matrix resin is A material for molding a liquid crystal resin composite, characterized by being dispersed in a first matrix resin. 2. The material for molding a liquid crystal resin composite according to claim 1, wherein the second thermoplastic matrix resin is a polyamide resin. 3. The molding material for a liquid crystal resin composite according to claim 2, wherein the weight ratio of the thermoplastic liquid crystal resin in the sub-composite exceeds 50%, and the sub-composite contains The weight ratio of the whole molding material is 3
% Or more and 50% or less, a material for molding a liquid crystal resin composite. 4. The material for molding a liquid crystal resin composite according to claim 1, wherein the second thermoplastic matrix resin is a polyester resin. 5. The material for molding a liquid crystal resin composite according to claim 4, wherein the weight ratio of the thermoplastic liquid crystal resin in the sub composite is 2% or more, and A molding material for a liquid crystal resin composite, characterized in that the weight ratio in the whole molding material is 3% or more and less than 60%. 6. A thermoplastic liquid crystal resin, a first thermoplastic matrix resin having a minimum moldable temperature lower than a liquid crystal transition temperature of the liquid crystal resin, and a minimum moldable temperature higher than the first matrix resin. A second thermoplastic matrix resin is extruded at a temperature higher than the liquid crystal transition temperature and the minimum moldable temperature of the second matrix resin to prepare a material, and the prepared material is mixed with the liquid crystal transition temperature. A method for molding a liquid crystal resin composite, wherein the molding is performed at a temperature below the minimum moldable temperature of the second matrix resin and above the minimum moldable temperature of the first matrix resin.