JPH0586257A - Molding resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition providing remolded articles free from reduction in strength and rigidity by blending a matrix resin composed of PC/ABS with a specific amount of a liquid crystal polymer having a higher melting point than the matrix resin. CONSTITUTION:(A) A matrix resin composed of PC/ABS is blended with (B) 3-70wt.% liquid crystal polymer composed of preferably a thermoplastic liquid crystal polyester or liquid crystal polyester amide having a higher melting point (preferably >=20 deg.C higher melting point) than the component A wherein the fibrous liquid crystal substance blended in a molded article has 23 (preferably >=10) aspect ratio to give the objective composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a molding resin composition comprising a composite material of a thermoplastic resin and a liquid crystal resin. More specifically, the present invention relates to a remoldable molding resin composition.

[0002]

2. Description of the Related Art Conventionally, as a synthetic resin molded article having high strength and high rigidity, a thermosetting resin mixed with glass fiber, or a thermoplastic resin called a stampable sheet is made of long fiber glass. A material obtained by molding a mixed material into a predetermined shape is known. Further, a high-strength and high-rigidity synthetic resin in which carbon fiber is used instead of the glass fiber is also known.

Further, as a synthetic resin molded article having high strength and high rigidity in which glass fibers and carbon fibers are not mixed, as shown in JP-A-1-320128, a thermoplastic resin and a liquid crystal resin (liquid crystal polymer) are used. Strands obtained by extruding a composite material consisting of the above at a temperature above the liquid crystal transition temperature of the liquid crystal resin are cut into lengths of 1 to 40 mm, and the obtained cut products are below the liquid crystal transition temperature of the liquid crystal resin. What is obtained by extrusion molding at the temperature of is also known.

By the way, recently, from the viewpoint of resource protection and the like, it is desired to recycle (re-mold) the synthetic resin body which has been molded. When recycling a molded article made of a synthetic resin body, the synthetic resin body is crushed to obtain a crushed piece made of a synthetic resin, and the crushed piece is heated and melted.
Molding a molten synthetic resin material into a molded product of a specified shape, or extruding a molten synthetic resin to obtain a molding material, and then molding the molding material into a molded product of a specified shape Is.

Heretofore, in the case of recycling a synthetic resin body having high strength and high rigidity, a fiber reinforced resin body prepared by mixing reinforcing fibers such as glass fibers and carbon fibers with a synthetic resin has been a target. ..

[0006]

However, when re-molding the fiber-reinforced resin body as described above, the crushed pieces obtained by crushing the fiber-reinforced resin body are mixed with the synthetic resin body for reinforcement. Since the fiber is cut into short pieces, the reinforcing fiber remains cut even in the molding material obtained by the re-molding. For this reason, the remolded product obtained by recycling had to be reduced in strength and rigidity as compared with the original molded product.

In view of the above, the present invention aims to prevent the strength and rigidity of a remolded product obtained by remolding a synthetic resin body having high strength and high rigidity from being lower than that of the original synthetic resin body. To aim.

[0008]

[Means for Solving the Problems] That is, the present invention provides a molding resin composition in which the matrix resin is polycarbonate / ABS contains 3 to 70% by weight of a liquid crystalline polymer having a melting point higher than that of the matrix resin, and Provided is a resin composition for molding, wherein a liquid crystal compound of a liquid crystalline polymer compounded therein has an aspect ratio of 3 or more.

The matrix resin used in the resin composition of the present invention includes polycarbonate resin and AB.
Mixture with S (acrylonitrile-butadiene-styrene copolymer resin) (hereinafter, simply "polycarbonate / ABS")
It may be said. ) Is mentioned. The matrix resin is commercially available. Specific examples of commercially available products include Techniace T105 [Sumitomo Nogatac Co., Ltd.], T-2600 (Teijin Kasei Co., Ltd.), Psycholoy 800 (Ube Sicon Co., Ltd.), and the like. One or more of these may be used. The content of matrix resin is
30 to 97% by weight is preferable with respect to the total weight of the resin composition.
When the amount of the matrix resin is less than 30% by weight, the moldability of the resin composition is deteriorated, and when it exceeds 97% by weight, the strength of the molded product becomes insufficient.

The resin composition of the present invention contains a liquid crystalline polymer. The liquid crystalline polymer has a fiber shape having an aspect ratio to be described later in the molded product of the resin composition,
It serves as a reinforcing material for molded products. Such a liquid crystalline polymer has a melting point higher than that of the above matrix resin, and is preferably 20 ° C. or higher. When the melting point is lower than that of the matrix resin, the liquid crystalline polymer does not become fibrous in the molded product, the orientation is not constant, and sufficient strength cannot be obtained. As the liquid crystal polymer, various conventionally known ones can be applied and are not particularly limited. Although various kinds of liquid crystal polymers are known, those particularly preferably used in the present invention are thermoplastic liquid crystal polyesters and liquid crystal polyester amides. As such,
Particularly preferably used are those described below. I.e.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

Here, Σni = 100. And it is particularly preferable that ni in each structural formula is 4 or more.

Further, in each formula, various substituents such as halogen may be added. Those shown in these are particularly preferable because they can be easily melt-molded with the modified polyester of the present invention. Further, it is easy to form a composite fiber having high strength and high elastic modulus.

Similarly, as the liquid crystal polyesteramide, a conventionally known one can be applied and is not limited at all. Particularly preferred are those represented by the following structural formulas. I.e.

[0019]

[Chemical 6]

[0020]

[Chemical 7]

[0021]

[Chemical 8]

Here, Σni = 100 in each structural formula. And, it is particularly preferable that ni in each structural formula is 15 or more. Further, in each formula, various substituents such as halogen may be added. Those shown in these materials have melt moldability and high strength as in the case of the liquid crystal polymer composed of polyarylate. The content of the liquid crystalline polymer is 3 to 70% by weight based on the total weight of the resin composition. If the content is less than 3% by weight, sufficient strength cannot be imparted to the molded product, and if it exceeds 70% by weight, the moldability of the resin composition is deteriorated.

Other additives such as a light resistance agent, an antioxidant and a plasticizer may be added to the resin composition of the present invention.

The resin composition of the present invention is molded or made into a molding material in a molten state, that is, in a state where it is heated to a temperature higher than the melting point of the liquid crystalline polymer to impart orientation to the polymer molecules. The state of imparting orientation to the polymer molecules is generally given by a method such as extrusion molding or injection molding. It may be directly molded by this method to obtain a molded article having high orientation (molecular orientation). However, it is usually formed into a pellet-shaped molding material after extrusion molding. The molding material may be melted and molded again by an extruder, an injection molding machine or the like. The temperature at the time of remelting is preferably higher than the melting point of the matrix resin and lower than the melting point of the liquid crystal polymer, because the liquid crystal resin retains a fibrous state. A flat material may be used as the molding material. In this case, the molding material plates may be overlapped and molded in the mold. In particular, the characteristics of the molded article can be changed by making the orientation directions the same or different.

The fibrous liquid crystalline polymer compounded in the above molded product has an aspect ratio (that is, length / thickness) of 3 or more, preferably 10 or more.

[0026]

EFFECTS OF THE INVENTION A remolded product is obtained by using the above molded product as a raw material, crushing it if necessary, and remelting and remolding according to the above-mentioned manufacturing method. The fibrous liquid crystalline polymer in the remolded product thus obtained is essentially the same as that in the raw material molded product and has an aspect ratio of 3 or more. Substantially equivalent. Further, such a re-molded product can be re-molded any number of times to give a re-molded product having substantially no strength reduction.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples. First, as a liquid crystal resin, Vectra A950 manufactured by Polyplastics Co., Ltd. (aromatic polyester, liquid crystal transition temperature:
280 ° C.) and Techniace T105 manufactured by Sumitomo Nogatac Co., Ltd. were used as PC / ABS, and both were mixed at a predetermined ratio to obtain a liquid crystal resin composite material.

Next, the liquid crystal resin composite material was subjected to initial extrusion molding. In this case, the extrusion molding conditions are as follows: A twin-screw extruder manufactured by Plastic Engineering Laboratory Co., Ltd. (screw diameter: 3
0 mm), the resin temperature is 290 ° C., the screw rotation speed is 100 rpm, the die diameter is 2 mm, and the shear rate is 17 mm.
The stretching ratio was set to 00 sec ^-1 and doubled. And
The above liquid crystal resin composite material was extruded while being stretched to obtain a strand-shaped initial molding material with a diameter of 1.4 mm for testing, and then a part of the initial molding material was cut into a length of 3 mm. Then, an initial pellet material was obtained.

Next, the above initial pellet material was injection molded to obtain a liquid crystal resin composite. The injection molding conditions in this case were a resin temperature of 250 ° C. using a 220 Ton injection molding machine manufactured by Toshiba Machine Co., Ltd. and a test piece mold. In this case, the resin temperature is set to 2 by using the injection molding machine and the mold of the spiral flow type (diameter: 6 mm semicircle).
A fluidity evaluation test was conducted at 50 ° C. and an injection pressure of 1000 kg / cm ² .

Next, the above-mentioned liquid crystal resin composite was crushed by a crusher V-360 manufactured by Horai Co., Ltd., and length: 3-4 mm.
After obtaining the crushed pieces, the crushed pieces are recycled and extrusion-molded to obtain a strand-shaped recycle molding material having a diameter of 1.4 mm for testing, and a part of the recycle molding material is length: It was cut into 3 mm to obtain a recycled pellet material.
The extrusion molding conditions in this case were the same as those in the initial extrusion molding.

Next, a tensile test was performed on the strand-shaped initial molding material and the recycled molding material. A universal testing machine (Autograph) manufactured by Shimadzu Corporation was used as a measuring machine, and the tensile speed was set to 20 mm / min.

FIG. 1 shows the results of tensile tests performed on the initial molding material and the recycled molding material.
In the region where the content of the liquid crystal resin exceeds 2 to 4%, fibrosis of the liquid crystal resin occurs, and the tensile strengths of the two are substantially the same over the entire range of the content of the liquid crystal resin, that is, according to the above remolding method. It was confirmed that the strength did not decrease despite remolding the high-strength synthetic resin.

FIG. 2 shows the relationship between the liquid crystal resin content and the flow length ratio, and it is clear that when the liquid crystal resin content exceeds 70%, the fluidity is extremely lowered and it is difficult to use as a molding material. Became. From the above consideration, when PC / ABS is used as the thermoplastic resin, the content of the liquid crystal resin is 3
It is preferably in the range of ˜70%.

Further, the morphological observation of the initial molding material and the recycling molding material with an electron microscope (SEM) showed that when the content of the liquid crystal resin was 3%, most of the liquid crystal resin was granular and partly. Was fibrous. Further, when the content of the liquid crystal resin was 4%, 6% and 8%, the liquid crystal resin was fibrous. From this result, it can be understood that when the content of the liquid crystal resin is 2 to 4% or more, the liquid crystal resin is fibrillated and the tensile strength is improved.

[Brief description of drawings]

FIG. 1 is a graph showing the results of a tensile test for an initial molding material and a recycling molding material obtained in Examples.

FIG. 2 is a graph showing the liquid crystal resin content and the flow length ratio in the molded products obtained in the examples.

Claims (1)

[Claims] 1. The matrix resin is polycarbonate /
The molding resin composition which is ABS contains 3 to 70% by weight of a liquid crystalline polymer having a melting point higher than that of the matrix resin, and the liquid crystal compound of the liquid crystalline polymer compounded in the molded product has an aspect ratio of 3 or more. A molding resin composition comprising: