JP2881782B2 - Thermotropic liquid crystal polymer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermotropic liquid crystal polymer composition.

More specifically, the present invention relates to a low specific gravity thermotropic liquid crystal polymer composition capable of producing various molded products excellent in physical properties and surface appearance by an extrusion molding method, a compression molding method, an injection molding method or the like.

[Conventional technology and problems]

The thermotropic liquid crystal polymer is characterized in that molecular chains are oriented by an external force such as shear orientation or extension orientation in a molten state, and the orientation of the molecular chains is frozen in a cooling process. Therefore, the elastic modulus, strength, and the like in the orientation direction take extremely large values, and conversely, the coefficient of linear expansion becomes extremely small, so that there is a possibility that the material will be industrially useful. However, on the other hand, since the anisotropy is large, the elastic modulus and strength in the direction perpendicular to the orientation direction are small,
In some cases, the resin surface layer may be peeled off.

In order to solve such a problem, there has been proposed a method of reducing anisotropy by filling a fibrous filler or a plate-like filler. In such a method, various physical properties such as mechanical properties, dimensional accuracy, and molding shrinkage are improved. Particularly in the field of injection molding, a dimensional accuracy is excellent, and a molded article having a good elastic modulus and a good coefficient of linear expansion can be obtained. It is being recognized that it is extremely useful in industry.

However, since such fillers generally have a large specific gravity, they have the disadvantage that if they are filled in an amount sufficient to reduce the anisotropy, the weight of the molded article increases. Further, a molded article filled with such a filler generally has poor appearance and has a so-called satin-like surface appearance, and thus has a problem in use as an exterior material. When the filler is not used, its surface gloss is good, but since the flow mark does not disappear, there is still a problem in using it as an exterior material.

[Means for solving the problem]

The present inventors have conducted intensive studies in view of the above-described problems, and found that a liquid crystal polymer exhibiting optical anisotropy when molten is filled with a specific organic material and a filler having a specific particle size, thereby solving such problems. The inventors have found that the points can be solved, and arrived at the present invention.

That is, the gist of the present invention is that the lower limit of the moldable temperature is 35
A thermotropic liquid crystal polymer of less than 0 ° C. is contained in an amount of 10% by weight or more, and a melting temperature or a decomposition temperature selected from the group consisting of wholly aromatic polyesters, wholly aromatic polyamides, and wholly aromatic polyamideimides is 350 ° C. or more A polymer or oligomer of, or a phthalocyanine-based, polyazo-based, and a quinacridone-based organic crystalline compound having a sublimation temperature or melting temperature of 350 ° C or higher, and an organic filler having a particle size of 100 microns or less.
The present invention relates to a thermotropic liquid crystal polymer composition containing 0.1% by weight or more. ADVANTAGE OF THE INVENTION According to this invention, anisotropy, such as a mechanical physical property, can be eased, and since the specific gravity of an organic filler is small compared with an inorganic filler, the specific gravity of a composition can also be made small. The appearance of the molded article obtained from the composition of the present invention is such that the flow mark disappears and the surface gloss is excellent as compared with the inorganic filler-filled system. Further, the present invention has a feature that a molding cycle can be shortened even when a molded article is molded by an injection molding method.

 Hereinafter, the present invention will be described in detail.

The organic filler according to the present invention is a solid at 350 ° C. or lower, whose constituent elements are mainly composed of carbon, hydrogen, oxygen, nitrogen, sulfur and the like, and include a halogen element or a metal element, an alkali metal element, an alkaline earth metal element and the like. May be partially included. Such an organic filler may be a low molecular compound as long as it is in a solid state at 350 ° C.
It may be a high molecular compound as long as it does not soften or decompose or melt at ℃. Such organic fillers can be selected from polymers or oligomers consisting of wholly aromatic polyesters, wholly aromatic polyamides, wholly aromatic polyamide-imides, or phthalocyanine-based, polyazo-based, quinacridone-based organic crystalline compounds that have sublimation temperatures or Compounds having a melting temperature of 350 ° C. or higher can be selected. Such an organic filler can be obtained by pulverization, freeze pulverization, a precipitation step at the end of the synthesis reaction, a precipitation step in a poor solvent, or the like. The particle size of the obtained organic filler is 100 microns or less. If a filler having a particle size larger than 100 microns is filled, not only the physical properties of the molded article are reduced, but also the surface appearance of the molded article is remarkably reduced, which is not preferable. On the other hand, the filling amount is 0.1% by weight or more, preferably 60% by weight or less. If the amount is less than 0.1% by weight, the effect of improving the molding cycle is not recognized. If the filling amount is more than 60%, the mechanical properties of the molded product are undesirably reduced to a level that cannot be practically used. When the thermotropic liquid crystal polymer is a polyester or a polyesteramide, it is preferable to use a filler composed mainly of an organic compound having an ester bond as the organic filler from the viewpoints of interface adhesiveness and surface gloss. The lower limit of the moldable temperature of the thermotropic liquid crystal polymer is less than 350 ° C.

The thermotropic liquid crystal polymer used in the present invention can be arbitrarily selected from the group of polyesters or polyesteramides comprising at least segments having the following structures.

1: Polyester -O-R-O- -CO-R-CO- -OR-CO- 2: Polyesteramide -O-R-O- -CO-R-CO- -OR-CO-- NH-R-CO- -NH-R-NH- R in the structural formula can be arbitrarily selected from the following groups.

Further, each aromatic ring, aliphatic group, alicyclic group, and the like of R may be substituted with various substituents selected from the following groups.

In the present invention, another plastic polymer component may be further copolymerized or blended with the thermotropic liquid crystal polymer described above. However, in the present invention, the above-mentioned thermotropic liquid crystal polymer needs to be contained at least 10% by weight or more. 10% by weight
If the amount is smaller, it is difficult to obtain a molded article having excellent performance which can be a target of the present invention.

Other thermoplastic polymer components that can be copolymerized or blended include polyester, polyamide, polycarbonate, polythioether, polysulfide, polysulfone, and the like. Preferably it is polyester or polyamide.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these without departing from the gist thereof. In the following examples, the bending strength was
It measured according to ASTMD790. The specific gravity was measured by a density gradient tube method.

Example-1 NOVACCURATE E3 marketed by Mitsubishi Kasei Corporation
To 22 resin, 15% by weight of an organic filler, Econol E101, marketed by Sumitomo Chemical Co., Ltd. was added and kneaded at a kneading temperature of 275 ° C. using a twin-screw kneading extruder to obtain a resin composition. Was.

Here, NOVACCURATE resin is a thermotropic liquid crystal polymer composed of a polyethylene terephthalate component and a parahydroxybenzoic acid component. Econol E101 is a polymer formed by condensation from parahydroxybenzoic acid, and is a stable powdery organic filler free from sublimation, decomposition, melting, etc. at 350 ° C., and has a particle size of 50 μm or less.

Using such a resin composition, a flat plate of 100 mm × 100 mm × 3 mm was injection-molded with a film gate. A test piece was cut out from this flat plate in the resin flow direction (MD direction) and a direction perpendicular thereto (TD direction), and the bending strength was measured. The results are shown in Table 1.

Comparative Example-1 A flat plate was formed in the same manner as in Example, except that a resin (natural resin) to which no organic filler was added was used. The results are shown in Table 1.

It was found that the anisotropy of the physical properties of the liquid crystal polymer was greatly improved by filling the organic filler according to the present invention.

Example 2 The specific gravity of the molded product obtained in Example 1 was measured.

Comparative Example-2 The specific gravity of the molded product obtained in Comparative Example-1 was measured.

Comparative Example-3 In Example 1, glass fiber was used as the resin composition.
Except for using a thermotropic liquid crystal polymer (trade name: NOVACCURATE E322G15 manufactured by Mitsubishi Kasei Co., Ltd.) containing 15% by weight, the same procedure as in Example 1 was carried out, and the specific gravity of the obtained molded product was measured.

Table 2 shows the results of Example 2 and Comparative Examples 2 and 3.

The specific gravity of the glass fiber-filled system exceeded 1.5, but in Example 2, the specific gravity was almost the same as that of the natural resin.

Example-3, Comparative Examples 4 and 5 The appearance of the molded products obtained in Example-1, and Comparative Examples 1 and 3 was evaluated.

[Effects of the Invention] The thermotropic liquid crystal polymer composition of the present invention is excellent in mechanical strength and surface appearance and has a small specific gravity, so that a molded article having excellent physical properties can be obtained by various molding methods.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-26656 (JP, A) JP-A-63-146958 (JP, A) JP-A-59-85733 (JP, A) JP-A-1- 261417 (JP, A) JP-A-2-102245 (JP, A) JP-A-2-102258 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 1/00-101 /14

Claims (1)

(57) [Claims] 1. A thermoplastic resin containing at least 10% by weight of a thermotropic liquid crystal polymer having a lower limit of a moldable temperature of less than 350 ° C. and selected from the group consisting of wholly aromatic polyesters, wholly aromatic polyamides, and wholly aromatic polyamideimides. Polymer or oligomer whose melting temperature (decomposition temperature if no melting temperature) is 350 ° C or higher, or sublimation temperature or melting temperature selected from the group consisting of phthalocyanine, polyazo, and quinacridone systems is 350 ° C or higher A thermotropic liquid crystal polymer composition, comprising 0.1% by weight or more of an organic filler having a particle size of 100 microns or less.