JPS6058829A - Manufacture of liquid crystal polymer molding high in elastic modulus with low coefficient of linear expansion - Google Patents

Abstract

PURPOSE:To obtain the titled molding large in the elastic modulus but small in the coefficient of linear expansion with an excellent dimensional stability by extruding a polymer of a melt liquid crystal at a specified shearing speed to form a thermotropic liquid crystal with polymer molecules oriented lengthwise. CONSTITUTION:A polymer of a melt liquid crystal is extruded at the shearing speed of almost more than 10<2>sec<-1> from an extruder cross head die 2, solidified by cooling through a cooling tank 4 or the like and then, wound with a winder 5 to obtain a polymer molding with polymer molecules oriented lengthwise. It should be noted that the liquid crystal polymer shall have the intrinsic viscosity of at least 0.3 and aromatic polyester is preferably used to enable the formation of an anisotropic melt phase at a lower temperature than 300 deg.C, containing the group of (A) formula I , the group of (B) formula II and the group of (C) formula III while containing 37.5-16.7mol% of the components A and B in the equal quantity each and 25.0-66.6mol% of the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a liquid crystal polymer molded article having a small coefficient of linear expansion in the longitudinal direction and a large modulus of elasticity.

[Prior art]

Generally, plastic molded products are obtained by extruding a molten polymer using an extrusion device, but because the molecular chains of the plastic molded products obtained in this way are randomly oriented, the coefficient of linear expansion is low. Thick (and elastic modulus is small. Therefore, a process to reduce the coefficient of linear expansion in the longitudinal direction and to increase the elastic modulus was essential. Conventionally, such stretching methods have only been used to uniformly stretch the film from the outside using hot rolls, etc.) A method of stretching with zero force heating has been used.

However, in this method, the portions that were oriented and crystallized by stretching were also heated, resulting in a decrease in strength and insufficient stress, which placed a limit on highly oriented crystallization. Therefore, the coefficient of linear expansion and modulus of elasticity were not satisfactory compared to theoretically expected values. In addition, the glass molded product thus produced shrinks due to reorientation when left at room temperature for a long period of time or is heated to 21 II above the softening temperature, resulting in poor dimensional stability.

[Purpose of the invention]

The present invention was made to solve these problems,
The purpose is to provide a method for producing a plastic molded product that has excellent dimensional stability, a low coefficient of linear expansion, and a high modulus of elasticity.

[Structure of the invention]

To summarize the present invention, the present invention is an invention of a method for producing a liquid crystal polymer molded article having a low coefficient of linear expansion and a high modulus of elasticity. It is characterized in that it is extruded to obtain a polymer molded article in which the polymer molecules are oriented in the longitudinal direction.

When certain crystalline polymers are heated, they may go through a state of crystalline anisotropy and liquid fluidity before melting into a liquid.

This state is called liquid crystal, and the liquid crystal produced by heating is called thermotropic liquid crystal. A polymer in a liquid crystal state when no external force is applied is generally an aggregate of domains in a certain arrangement order. It is known that when an external mechanical force is applied to this system, the domains deform, flow, and even collapse, and the polymer chains become oriented in the flow direction.

In this way, the liquid crystal is oriented according to the direction of flow, so thermo
The melt viscosity of zero-pick liquid crystal polymers is extremely low (and it is known that in shear flow, the higher the shear rate, the lower the melt viscosity.

As a method for fluidizing and aligning a thermotropic liquid crystal polymer, there is a method of discharging the liquid crystal polymer from a small nozzle. That is, by injection molding, or in extrusion molding, by discharging the thermotropic liquid crystal polymer from a /JX small die, the polymer GI can be oriented in the injection direction or extrusion direction. The liquid crystal oriented in this manner maintains its oriented state even after the temperature is lowered, so it has good dimensional stability (the coefficient of linear expansion in the orientation direction is low and the modulus of elasticity is high).

In this method, the inventors have discovered that the
It has already been clarified in the invention of ``One-Element Fiber Corded Wire'', No. 8-80797, 1983, that the value of the coefficient of linear expansion greatly depends on the speed. At the nozzle of the extruder head /”f,
A liquid crystal polymer subjected to a shear rate of 10 sec or more, preferably 10 to 10 sec, exhibits a low coefficient of linear expansion of 10-5 C-1 or less.

The present invention applies this thermotropic liquid crystal poly-q- to a plastic molding material, and according to the present invention, excellent dimensional stability and a low linear expansion coefficient can be easily obtained.

The liquid crystal polymer used as the plastic molding material in the present invention can be used as long as it has an intrinsic viscosity of at least 0.3 and exhibits a liquid crystal state in a molten state (thermotropic liquid crystal polymer). Among these, particularly preferred are the following divalent groups (AJ, (
BJ and (0) are included, and the group (AJ and group (BJ) are equally added in 10 to 50 mol%, and the group (0) is added to 40 to 80 mol%.
Including mole%.

It is an aromatic polyester that forms an anisotropic melting phase (liquid crystal phase) at temperatures as low as about 3 aaC.

0 0 (BJ -0~0H2-0H2-0- [Examples] Examples of the present invention will be explained below based on the drawings, but the present invention is not limited to these examples.

FIG. 1 is a schematic configuration diagram of a manufacturing apparatus used in Examples.

Example 1 FIG. 1 shows an example of manufacturing a plastic tape by extrusion molding. In FIG. 1, reference numeral 1 is a tape-shaped liquid crystal polymer, 2 is a crosshead of an extruder, 3 is a straight part of the die, 4 is a cooling tank, and 5 is a winder. The polymer in a molten liquid crystal state is formed into a tape as it passes through the crosshead gouer 2 and the linear section 3 of the die, solidifies in the cooling tank 4, and then is wound up by the winder 5. In this example, the tape material is polyethylene terephthalate (hereinafter referred to as P
(abbreviated as ET) was treated with 40 mol % of tp-acetoxybenzoic acid (60 mol %) to form a thermotropic liquid crystal. The IQT speed at the exit of the goo during tape production is determined by the extrusion speed of the resin and the size of the groove at the exit of the goo.

Now, the flat groove at the exit of the goo is io, 1+u+, 100 mm horizontally, and the straight section length is 4 mm. Using an extrusion PA equipped with a rad die, extrude the modified PET resin at 240C1 at an extrusion speed of 20 crl/min. , when winding at 2゜m for 7 minutes, the shearing speed at the goo exit is 2 X j 05s
ec-', the coefficient of linear expansion of the resulting tape with a thickness of 0.1 mm and a width of 100 cm is -2X10 C-, and the tensile modulus is 1
It was found to be 8 GPa. Also, use this tape 1
Even after being left at 70c for one day, no dimensional change was observed.

The plastic tape of the present invention is disclosed in Japanese Patent Application No. 56-2.
By using the glass stretching method of No. 08031 in combination, it is possible to further increase the flat elastic modulus. That is, a fin with a thickness of 1.0 manufactured by the manufacturing method shown in FIG.
A tape with a width of 100 mm is heated using an induction heating device (oscillation frequency 2
．． 45 GHz.

When stretched at an ambient temperature of 170 r and a stretching speed of 150 n for 7 minutes (stretching ratio: 10 times) using an output of 1.5 KW)
The elastic modulus of the obtained tape with a thickness of 0.5 mm and a fin width of 20 mm was 21 GPa, which was about 1.2 times higher than that without electric heating stretching. .

Example 2 FIG. 2 shows an example of plastic tape production by calendar molding. In FIG. 2, numerals 1 and 5 have the same meanings as in FIG. 1, 6 is a calender roll, and 7 is a reservoir of heated and melted resin.

The thermoplastic resin in a molten liquid crystal state in the liquid reservoir 7 is molded into a tape shape when passing through the calender roll 6, solidified, and wound onto the winder ff15.

In this example, the same PET-1)-acetoxybenzoic acid copolymer as in Example 1 was used as the tape material. When this resin passes through the calender rolls 6, it is subjected to shear stress, resulting in highly oriented molecular orientation in the rolling direction. The speed of cracking applied to the resin increases as the gap between the rolls becomes smaller and as the rotational speed of the rolls increases. Now, the roll diameter is 50cm, the gap between the rolls is 0.1cm, and the
If the rotation speed is 30 m/min, the shear rate is 1.6
X 103 sec-1 and the obtained thickness is 011 m
, the coefficient of linear expansion of a tape with a width of 100 cm is -2X10 C"-
The tensile modulus was 16 GPa, and no dimensional change was observed even after being left in a 170C air constant temperature bath for one day.

Example 3 FIG. 3 shows an example of manufacturing a plastic pipe by extrusion molding. In FIG. 3, numeral 8 is a vibrator-shaped liquid crystal polymer, and 2 to 5 have the same meanings as in FIG. 1. The liquid crystal polymer in a molten state crosses through a Rad die 2 and is shaped into a vibrator as it passes through a straight section 3 of the die, solidifies in a cooling tank 4, and then is wound up by a winder 5. In this embodiment, the pipe material used is a thermotropic liquid crystal obtained by treating 50 mol% of PET with 50 mol% of p-acetoxybenzoic acid. Now, using an extruder equipped with a rad die, the modified P
gT resin was extruded at a 220C1 extrusion speed of 50 d/min, 7
When winding at 0 m/min, the shear speed at the goo exit is '1. I
．． 4m.

The coefficient of longitudinal melt expansion of a pipe with an inner diameter of 3.1 is 1X 1
0-61:'', the tensile modulus was 15 GPa, and no dimensional change was observed even when this pipe was left in a 1500 air constant temperature bath for one day.

Example 4 FIG. 4 shows an example of filament production by the melt-proofing method. In FIG. 4, numerals 4 and 5 have the same meanings as in FIG. 1, 9 is a filamentary liquid crystal polymer, 10 is a spinneret block of the extruder head, 11 is a spinneret hole, and 12 is a pulley. The polymer in the bath-molten liquid crystal state is formed into a filament when passing through the spinneret hole 11, solidified in the cooling bath 4, and then passed through the pulley 12 to the winder 5.
It is wound up. In this example, the same modified pg'r resin as in Example 3 is used as the filament material. The shear rate during filament production is determined by the extrusion rate of the resin and the hole diameter of the spinneret hole. Now, using an extruder equipped with a spinneret hole with a diameter of 0.1 m, the modified PgT resin was
Melt spinning at 0C1 extrusion speed 305 m 37 minutes, 3.8
m When winding takes 7 minutes, the shear rate at the mouth hole exit is 5 X I Q3set: 1, and the obtained 0,
The coefficient of linear expansion of the filament of 1111IIφ is -2×1o
-7G-1, the tensile modulus was found to be 20 GPa. Further, no dimensional change was observed even when this filament was left in a 150C air constant temperature bath for one day.

Example 5 Figure 5 shows one example of manufacturing plastic tensile strength wire by extrusion molding.
Give an example. In FIG. 5, the reference numeral 13 is a rod-shaped liquid crystal polymer, and 2 to 5 are the same as in FIG. 1.
The polymer in a liquid crystal state is formed into a rod shape after passing through a cross-radial die 2 and a linear part 3 of the die, solidified in a cooling tank 4, and then wound up by a winding machine 5. In this example, modified PIE having the same composition as Example 1 was used as the tensile strength wire material.
T resin is used. Now, using an extruder with a die straight section of 4 days and a resin discharge hole diameter of 1.2 days, the modified PgT resin was
40C1 Extruded at extrusion speed 20 cl/min, 25.5 m
/min, the shear rate at the goo exit is 2
X10311, and the elastic modulus of the obtained rod of 1, Orunφ was found to be 190 Pa. Further, even when this rod was left at 170C for one day, no dimensional change was observed.

Example 6 The plastic tensile strength body according to the invention can be coated with a jacket by a two-layer coextrusion method.

Figure M6 shows an example of two-layer coextrusion according to the present invention, and numeral 14 is a rod-shaped liquid crystal polymer covered with an outer plate;
15 is a liquid crystal polymer as a rod material, 16 is a thermoplastic resin as a jacket material, 17 is a cross-to-rad die for two-layer coextrusion, and 3 to 5 have the same meanings as in FIG. After passing through the crosshead die 17 and the linear part 3f of the die, the thermoplastic resin 16 for the jacket 16 in a molten state and the liquid crystal polymer 15 in a liquid crystal state are formed into a pipe shape and a rod shape. After being solidified in step 4a5, it is wound up in winder 4a5. As described in the above embodiment, even in two-layer simultaneous extrusion, the shearing rate in the goo straight portion can be changed by appropriately selecting the diameter of the central resin discharge hole and the extrusion rate of the resin. In this example, the extruder was equipped with a Herado die with four fins on the die straight part, a resin discharge hole diameter for the rod of 1.2 tsφ, a resin discharge inner diameter of 2.2 mφ for the jacket, and a large outer diameter of 3.5t1 mφ for the resin discharge for the jacket. Using a machine, the PE used in Example 1 was used as the material for the rod.
T-p-acetoxybenzoic acid copolymer, using polyvinyl chloride as the outer covering material, and 240C in the center part of the head.
1 Set the outer peripheral part to 220C, and set the extrusion speed of the rod to 2.
Each of the six resins was extruded for 0-7 minutes at an extrusion speed of 1 o o crlZ for the jacket and wound up for 25.5 m in 7 minutes. The elastic modulus of the obtained tensile strength wire with a rod diameter of 1 tnmφ and a coating outer diameter of 2 mmφ was 18 GPa. In this example, polyvinyl chloride was used as the material for the jacket, but the material is not limited to this; other thermoplastic resins such as polyethylene, polypropylene, polycarbonate, nylon, etc. can be used.

〔Effect of the invention〕

As explained above, in the present invention, approximately 102 sec-'
Since a liquid crystal polymer that is highly susceptible to molecular orientation at the above shear rate is used as a plastic molding material, it has the advantage of being able to produce plastic molded products with excellent dimensional stability, low coefficient of linear expansion, and high modulus of elasticity just by the extrusion process.

[Brief explanation of drawings]

1 to 6 are schematic diagrams of a manufacturing apparatus used in an embodiment of the present invention. 1: Tape-shaped liquid crystal polymer, 2: Rad die to extruder cross, 3: Straight part of Rad die to extruder, 4: Cooling tank, 5:
Winder, 6: Calendar roll, 7: Liquid reservoir, 8: Pipe-shaped liquid crystal polymer, 9: Filament-shaped liquid crystal polymer, 1
0: Spinneret block of extruder head, 11: Spinneret hole, 12: Pulley, 15: Sun-shaped liquid crystal polymer,
14: Rondo-shaped liquid crystal polymer covering the outer cover, 15: Liquid crystal polymer, 16: Thermoplastic resin for the outer cover, 17: Crosshead for two-layer coextrusion. Figure 7 ``LJ L/') \ \ Procedural amendment (voluntary amendment) September 17, 1980 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case Patent Application No. 166527 of 1982 Z
Title of the invention Method for manufacturing a liquid crystal polymer molded product with a low coefficient of linear expansion and a high modulus of elasticity 3, Relationship to the amended person's case Patent applicant address 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Name
(422) Representative of Nippon Telegraph and Telephone Public Corporation Tsune Shinto 5, date of amendment order Voluntary amendment & subject of amendment (1) Scope of claims in the specification (2) Detailed explanation of the invention in the specification Contents of the amendment (1) The claims section of the specification will be amended as a separate sheet. (2) The detailed explanation of the invention section of the specification will be amended as follows. b) Change “10-50” on page 6, line 8 of the specification to “57.5”
~16.74, and “40-80” on line 9 of the same page is changed to “25.
0 to 66.6". (b) Add the following statement after ``Understanding,'' in the 7th line from the bottom of page 7. "Said (4), middle), (2a6 mol% of each Cl group, 2a
6 mol% and 42.8 mol%.'' ) Add the following statement next to ``processed'' on page 10, line 11 of the same. [Said (4), a3), (353 mol% of each C1 group, 3
3.3 mol% and 354 mol%.'' 2. Scope of Claims 1. The polymer in the molten liquid crystal state is
A method for producing a liquid crystal polymer molded article having a low coefficient of linear expansion and a high modulus of elasticity, characterized by extruding at a shear rate of - or higher to obtain a polymer molded article in which the polymer molecules are oriented in the longitudinal direction. 2. The method of claim 1, wherein Z the shear rate is about 103 to 1 eC1. 3. The method according to claim 1, wherein the molded article is a tape, pipe, rond, or filament. 4. The liquid crystal polymer has an intrinsic viscosity of at least 0.3 and contains the following groups represented by the following formulas: -0-C-OH, -0- and the group (5) and the group) are 37.5 to 1&7
The claims are made of an aromatic polyester containing 250 to 66.6 mol% of groups (C1) and capable of forming an anisotropic melt phase at a temperature lower than about 300°C. The method described in paragraph 1.

Claims (1)

[Claims] 1. Bo I)-r- in a molten liquid crystal state is
A method for producing a liquid crystal polymer molded product having a low coefficient of linear expansion and a high modulus of elasticity, which comprises extruding at a shear rate of sec-' or more to obtain a chilimer molded product in which polymer molecules are oriented in the longitudinal direction. 2. The method of claim 1, wherein the shear rate is about 103 to 10'5 ec-'. & The method according to claim 15, wherein the molded product is a tape, pipe, rond, or filament. 4. The liquid crystal polymer has an intrinsic viscosity of at least 0.3, contains each group represented by the following formulas (A), (BJ and (C)), and contains a group (AJ and a group (BJ) Contains an equal amount of 10 to 30 mol%, and groups (including 40 to 80 mol% of CiJ,
The method of claim 1, comprising an aromatic polyester capable of forming an anisotropic melt phase at temperatures below about 500C.