JPH04140115A - Manufacture of polymer molded body - Google Patents

Abstract

PURPOSE:To improve orientation effect under magnetic field and obtain polymer molded body excellent in mechanical properties such as elastic modulus and the like by a method wherein heat treatment is carried out to thermal liquid crystal polymer at the temperature higher or lower than its melting point before the application of magnetic field on the liquid crystal melt of the thermal liquid crystal polymer. CONSTITUTION:As the thermal liquid crystal polymer, polyester-based one, polyazo methine-based one or copolymer-based one such as polyester amide- based one or the like can be used. For example, yellow polyazo methine (having the melting point of 275 deg.C) is obtained by melting methyphenylenediamine and terephthalaldehyde with pyridinecontaining N-pyrrolidone so as to be react with each other. Out of the resultant polymer, rod with the diameter of 2mm is manufactured at 280 deg.C by melt compression forming. Then, the rod is heat- treated at 280 deg.C (molten state) for 40min in a heat resistant polymer vessel and, after that, cooled down to room temperature. In succession, the rod is heated again up to 290 deg.C and subjected to the magnetic field of 18kG for 5min and finally cooled down in magnetic field to room temperature so as to form the rod with the diameter of 2mm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a polymer molded article. For more information,
The present invention relates to a method of manufacturing a polymer molded body using a magnetic field.

[Conventional technology and its issues]

The properties of a polymer molded body are strongly influenced by the orientation state of its molecular chains. Therefore, methods such as stretching and liquid crystal spinning have been developed and used to produce high-performance molded bodies. One such method is the application of a magnetic field to thermoliquid crystalline polymers, which is a relatively newly developed method. However, this method has a problem in that it requires a long time for molding because the energy is small.

[Means to solve the problem]

In the present invention, prior to applying a magnetic field to a liquid crystal melt of a thermoliquid crystalline polymer, the thermoliquid crystalline polymer is subjected to heat treatment at a temperature of several tens of degrees Celsius above or below the melting point, thereby achieving orientation in a magnetic field. It provides a way to improve effectiveness.

That is, the present invention provides a method for producing a polymer molded article by applying a magnetic field to a thermoliquid crystalline polymer in a liquid crystal state, in which a solid thermoliquid crystalline polymer molded into a solid thermoliquid crystalline polymer molded in substantially the same shape as a cough polymer molded article is injected into a solid phase. melting a preform obtained by heat-treating the polymer in a molten state, or by heat-treating a thermoliquid crystalline polymer in a molten state held in approximately the same shape as the polymer mold, and then cooling it below its melting point;
This is a method for producing a polymer molded article, which is characterized by applying a magnetic field and molding it in a liquid crystal state.

The present invention will be explained in detail below.

The thermal liquid crystal polymer used in the present invention is not particularly limited, but a wide range of polymers can be used, including polyester, polyazomethine, and copolymers such as polyesteramide. Specific examples of thermoliquid crystal polymers suitably used in the present invention are shown below.

(2) Polyesters and copolymers thereof Preferred examples include polymers synthesized from combinations of diols, dicarboxylic acids, oxycarboxylic acids, diamines, aminocarboxylic acids, and aminophenols listed below.

A' A, A' OH, -COOH or -NH2 and derivatives thereof (including cases where A and A' are the same) R 0- -0-1-CHl-+TO--C=C and these compounds It also includes compounds synthesized from nuclear substitution by halogen, alkyl, phenylene, etc.

Preferred specific examples of the dicarboxylic acid are terephthalic acid, isophthalic acid, bis-4-carboxylphenyl 1,4-<nzene, 44'-carboxyldiphenyl, naphthalene-
2,6-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, diphenylketone-4,4'-dicarboxylic acid, methylterephthalic acid, chloroterephthalic acid, phenylterephthalic acid, 2,5-dimethylterephthalic acid, diphenyl-3 ,3'-dimethyl-4,4'-dicarboxylic acid, 1,
2-bis(phenoxy)ethane-4,4'dicarboxylic acid, 1,2-bis(2-chlorophenoxy)ethane-4,
4'-dicarboxylic acid.

Preferred specific examples of diols include chlorohydroquinone,
Methylhydroquinone, 26-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 33'-dimethyl-4,4'-dihydroxydiphenyl, acetoxyhydroquinone, nitrohydroquinone, dimethylaminohydroquinone,
15-dihydroxynaphthol, 16-dihydroxynaphthol, bis(4-hydroxyphenyl) 1,4-henzene, 1,2-bis(phenoxy)ethane-4,4'
-diol, 1,2-bis(phenoxy)ethane-4-
Amine-4'-diol.

Preferred specific examples of oxycarboxylic acids are p-hydroxybenzoic acid, 2-hydroxy, 6-carboxynaphthalene-4-hydroxybiphenylcarboxylic acid and derivatives thereof.

The thermoliquid crystalline polyester can be synthesized by a known method such as melt polymerization, and the ratio of each monomer in the above monomer combination is determined depending on the required physical properties, molding conditions, etc.

(2) Polyazomethine and its copolymer Synthesized from the following combinations of dialdehydes and diamines.

B+CH2-)-=-・B' B, B' knee COH or -NH.

(Including cases where B and B' are the same) R: -0--=o-CH2CH2-ONHCCI--
COO CH=CH-COO Also used are derivatives obtained by nuclear substitution of these compounds with halogen, alkyl, phenylene, etc.

Specific examples of dialdehyde include terephthalaldehyde, chloroterephthalaldehyde, methylterephthalaldehyde, 2-hydroxyterephthalaldehyde, 2.6
-Naphthalenedialdehyde, 1,4-naphthalenedialdehyde, isophthalaltehyde, bis(4-formylphenyl)-1°4-benzene, bis(3-formylphenyl)-1,4-benzene, 4-formylphenyl- 3
Formylphenyl-1,4-benzene, 1,5-naphthalene dialdehyde, 4,4'-diformyldiphenyl,
4.3'-formyldiphenyl, 2methoxyterephthalaldehyde, 2-phenylterephthalaldehyde, 2.
Examples include 3-bis(phenoxy)butane-4,4'-dialdehyde, 2.3-bis(phenoxy)propane-4,4'-dialdehyde, and 1,3-bis(phenoxy)propylidene-44'-dialdehyde. Among these, preferred are terephthalaldehyde, 2,6 naphthalene dialdehyde, 4,4'-diformyldiphenyl, and 2-methylterephthalaldehyde.

Specific examples of diamine include 1,4-phenylenediamine, methyl-1,4-phenylenediamine, chloro-1
, 4-phenyleneamine, 3,3'dimethyl-4,4'
-diaminobiphenyl, 3゜3'-dichloro-4,4'
-diaminobiphenyl, 2,2'-dichloro-4,4'
-diaminobiphenyl, 2,2'-dimethyl-4,4'
-Diaminovininyl, 2,6-nuclenediamine, 4
．． 4'-diaminodiphenyl sulfone, 4.4'-diaminodiphenyl ether, bis(4-aminophenyl)
Ethane, 1,4-bis(4-aminophenyl)butane,
1.2-bis(4-aminophenoxy)ethylene, 3.
3'-diaminohensiphenone, 1,2-bis(phenoxy)ethane-44'-diamine, 1,2-bis(3
-methylthiophenoxy)ethane-4,4'-diamine, 13-bis(phenoxy)propane-4,4'-diamine, and among these, preferred are methyl-1,
4-phenylenediamine, 2,2'-dimethyl-4,4
'-diaminobiphenyl, 2,6 naphthalenediamine,
1, 2-bis(4-aminophenoxy)ethylene.

Copolymerized polyazomethine can be obtained from the dialdehyde, diamine, and amide bond-containing diamine by polymerization preferably using a polar solvent. That is, a diamine and an amide bond-containing diamine are dissolved in a polar solvent selected from N,N-dimethylacetamide, N-methylpyrrolidone-2, hexamethylphosphoramide, or a mixture thereof, with lithium chloride included therein. It is produced by adding dialdehyde in an amount approximately equivalent to the total amount of diamine and amide-bonded diamine, and reacting at room temperature for several hours to several days.

The preferred degree of polymerization of these thermoliquid crystalline polymers is determined from the viewpoints of magnetic field orientation and performance of the molded product.

Expressing this in terms of dynamic viscosity, the value at the temperature at which a magnetic field is applied is 10 to 100,000 poise, preferably 100 to 100 poise.
A thermoliquid crystalline polymer exhibiting 0.00 voids is preferably used.

Thermo-liquid crystalline polymers can be used alone or in combination with other polymers, organic and inorganic materials, such as dyes, pigments, fillers and fibrous additives, as long as the liquid crystallinity is not lost. .

The present invention is characterized in that, when forming the above-mentioned thermoliquid crystalline polymer by applying a magnetic field in the liquid crystal state, heat treatment is performed in advance. The thermoliquid crystalline polymer to be heat-treated needs to be preformed in advance into a shape that is the same as or close to the shape in the process of molding by applying a magnetic field. This is to minimize the flow deformation of the thermoliquid crystal polymer during the process of applying a magnetic field.

Heat treatment is performed in the solid state or in the molten state.

In the case of performing the heat treatment in a solid state, a preform molded into approximately the same shape as the final desired polymer molded product is heat treated.

In this case, the heat treatment is performed at a temperature and for a treatment time that does not melt the preform. Even at temperatures above the melting point, the treatment time may be shortened. The heat treatment temperature and treatment time are preferably about from the melting point (melting point -100"c) for several hours to several hours. When the heat treatment is carried out in a molten state, the shape is approximately the same as the final desired polymer molded product. For example, in a mold,
After heat-treating the thermoliquid crystalline polymer in the maintained molten state, it is cooled to below its melting point to form a preform. In this case, the heat treatment temperature and treatment time are usually at a temperature of a liquid crystal state, and a time of 60 minutes or less is sufficient. These heat treatments significantly improve the effect of applying a magnetic field.

When forming by applying a magnetic field, the preform may be melted while maintaining its shape, and the magnetic field may be applied at a temperature at which the thermoliquid crystalline polymer is in a thermoliquid crystal state.

As a method for applying a magnetic field, it is sufficient to heat the above-mentioned heat-treated thermoliquid crystalline polymer preform and hold the melt in a thermoliquid crystal state in the magnetic field for a necessary period of time. At this time, it is better to avoid flow deformation of the polymer as much as possible. Furthermore, it is also not preferable to apply a field to the polymer immediately after it has been fluidly deformed.

After the orientation has progressed, the process of cooling and solidifying to fix the orientation structure can be carried out either in a magnetic field or by taking it out of the magnetic field. The applied magnetic field can be created using an electromagnet or the like. To obtain a high degree of orientation, a magnetic field of several thousand Gauss or more is required, and a magnetic field of 20,000 Gauss or more is preferred. In this case, it is preferable to use superconducting magnets. Further, the application time is about 5 to 90 minutes.

Typical examples of molded articles produced in the present invention include fibers, films, plates, and injection molded articles.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the examples unless it exceeds the gist thereof.

The degree of orientation in the examples was determined by determining the half (+!! width W) from the azimuthal distribution of X-ray diffraction intensity, and using the following formula.

Item 3U Example 1 and Comparative Example 1 150w+1 containing 2 mf2 of pyridine containing methyl enylene diamine (0.05 mol) and terentaldehyde (0.05 mol)! The solution of N-methylpyrrolidone ζ was stirred at room temperature for 8 hours. This reaction yielded yellow polyazomethine (melting point 275°C). Using this polymer, a rod with a diameter of 2 was manufactured by melt compression molding at 280°C. This rod was heat-treated at 280"C (molten state B) for 40 minutes in a heat-resistant polymer container with the same inner shape to prevent flow deformation of the boriadumetine, and then cooled to room temperature again at 290"C. After heating to ℃ and applying a magnetic field of 18 k for 5 minutes,
It was cooled to room temperature in a magnetic field and molded into a rod with a diameter of 2 am. The molecular orientation within this rod was evaluated using wide-angle X-rays.

The calculated degree of orientation was 2:80%. On the other hand, when a magnetic field was directly applied under the same conditions without heat treatment, the degree of orientation was 70%. In order to obtain the 80% degree of orientation using this method, it was necessary to apply a magnetic field for 40 minutes.

Example 2 and Comparative Example 2 2-hydroxy-6-carboxylnaphthalene (0,4
310'
Rods with a diameter of 2 mm were preformed using the C7' melt compression molding process.

This rod was heat treated at 230°C in a nitrogen stream for 12 hours. Thereafter, it was filled into a heat-resistant polymer container with an inner diameter of 2 m+, and a magnetic field of 100 kilogauss was applied at a temperature of 320'C for 20 minutes, and then cooled to room temperature to obtain two highly oriented diameter rods.

For comparison, a rod was formed by applying a magnetic field under the same conditions as above, using a rod immediately after preforming without heat treatment.

When the bending elastic modulus of these two rods was measured and compared, the rod of the present invention showed 56 GPa, and the comparative example showed 45 GPa.
This was a great improvement over G P a.

〔Effect of the invention〕

According to the method of the present invention, a highly oriented polymer molded article having excellent mechanical properties such as elastic modulus can be obtained.

In addition, since magnetic field forming is performed using a heat-treated preform,
The heat treatment device and the magnetic field forming device can be separated, which is industrially advantageous.

Claims (1)

[Claims] (1) In a method for producing a polymer molded body by applying a magnetic field to a thermoliquid crystalline polymer in a liquid crystal state, a solid thermoliquid crystalline polymer molded into almost the same shape as the polymer molded body is in a solid state. The preform obtained by heat treatment or heat treatment on a thermoliquid crystalline polymer in a molten state held in approximately the same shape as the polymer molded product and then cooling to below the melting point is melted and a magnetic field is applied in the liquid crystal state. A method for producing a polymer molded article, characterized by applying pressure and molding.