JP2008031332A - Fiber-reinforced polymer composition derived from organism and process for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a fiber-reinforced polymer composition derived from an organism that has a short fiber of a thermotropic liquid-crystalline polyester uniformly dispersed in the form of a single fiber into a polymer derived from an organism and is producing a molded article excellent in dynamic characteristics, durability, heat resistance and the like smoothly with good workability and good progression of the production without the occurrence of clogging or the like in a heating and kneading apparatus. <P>SOLUTION: The fiber-reinforced polymer composition derived from an organism is produced by blending and melt-kneading into a polymer derived from an organism a bundle of short fibers of a thermotropic liquid-crystalline polyester wherein the bundle of short fibers is constituted of short fibers temporarily bonded to each other through thermal fusion bonding with adhesive strength such as to separate the short fibers into each single fiber by heat and/or shearing force upon kneading. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fiber-reinforced biopolymer composition containing molten liquid crystalline polyester fibers as reinforcing fibers and a method for producing the same. More specifically, in the present invention, short fibers made of molten liquid crystalline polyester are spread and uniformly dispersed in a bio-derived polymer in the form of single fibers, such as mechanical properties, durability, heat resistance, etc. A method of smoothly producing a fiber-reinforced biopolymer composition capable of obtaining a molded article excellent in the properties of the above with good workability and processability, and a fiber-reinforced biopolymer composition obtained thereby, In addition, the present invention relates to a molded article made of the polymer composition.

Polyvinyl chloride, polyolefins such as polyethylene and polypropylene, polystyrene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyamides such as nylon are produced in large quantities and used in a wide range of applications. Yes. For example, a resin molded product made of polypropylene, polycarbonate resin, or the like is often used as a frame for electronic and electrical products.
The above-described polymer is usually produced using petroleum-based resources as raw materials, but petroleum-based resources are limited. When the supply amount of petroleum resources is reduced or when petroleum resources are depleted, polymers made from petroleum resources are likely to cause a significant increase in production costs and may be difficult to manufacture in some cases. Expected.
Moreover, since the above-mentioned polymers derived from petroleum resources are generally stable in the natural environment and difficult to decompose, some of them are recovered and reused after use, but most are disposed of by landfill or incineration. . In the case of landfill disposal, there is a problem of securing a disposal site. In the case of incineration disposal, carbon dioxide generated by incineration is one of the causes of global warming. In addition, polymers containing halogen such as polyvinyl chloride are liable to generate harmful gases upon incineration.

From the above points, research, development, and production of polymers derived from biological resources that can be repeatedly produced (plants, animals, microorganisms, etc.) have been conducted in recent years as alternatives to polymers derived from petroleum-based resources. It is like that.
However, since biological polymers are generally inferior in basic properties such as heat resistance and mechanical properties to polymers derived from petroleum-based resources, various functional materials can be added. It has been studied to improve the physical properties by devising the molding method.

  In general, inorganic fibers such as glass fibers and carbon fibers are mixed to improve the mechanical properties of organic polymers, including polymers derived from living organisms. When the polymer is kneaded or molded, the fiber length tends to be shorter than 1 mm, and as a result, there is a problem that the reinforcing properties inherent to the inorganic fiber cannot be fully utilized. When a large amount of inorganic fiber is mixed in the organic polymer in order to exert the reinforcing effect by the inorganic fiber, disposal treatment after use becomes a big problem.

  In addition, attempts have been made to mix plant fibers such as pulp, kenaf fiber, and cellulose fiber into an organic polymer. As one of such techniques, plant fibers are contained in a bio-derived polymer such as polylactic acid. It has been proposed to mix them (Patent Documents 1, 2, 3, etc.). However, in the case of these conventional techniques, the plant fiber is not sufficiently dispersed in the polymer, the reinforcing effect by the plant fiber is insufficient, the heat resistance is insufficient, etc. It wasn't.

Melt liquid crystalline polyester fiber (polyarylate fiber) is known as one type of high-strength / high elastic modulus fiber, and a plastic molded body (FRP) reinforced with molten liquid crystalline polyester fiber is also commercialized.
In addition, aramid fibers and polyarylate fibers (melting liquid crystal properties) are added to a resin composition in which kenaf fibers, which are one type of plant fiber, are mixed with biodegradable resins such as polylactic acid for the purpose of improving impact resistance and heat resistance. It has been proposed to further mix high-strength, high-impact fibers such as polyester fibers (paragraphs 0032 to 0033 of Patent Document 4).
The present inventors examined this known technique of mixing a molten liquid crystalline polyester fiber (polyarylate fiber) into a biodegradable resin such as polylactic acid. As a result, the liquid crystalline polyester was added to a biodegradable resin such as polylactic acid. When mixing and kneading the fibers in the form of short fibers, the melted liquid crystalline polyester short fibers are bulky, so they are agglomerated in the hopper and other supply path portions when supplied to a kneading apparatus such as an extruder. It is difficult to supply and transport stably due to clogging, and the molten liquid crystalline polyester short fibers are not sufficiently bitten into the screw of the extruder, so that the molten liquid crystalline polyester short fibers are smoothly put into the biodegradable resin and It turned out to be difficult to disperse uniformly.

  As a method for smoothly and uniformly dispersing molten liquid crystalline polyester fibers in biodegradable polymers such as polylactic acid and plant-derived polymers, binder resins such as polyurethane are used. A method is conceivable in which a short fiber bundle obtained by converging the fiber bundle into a fiber bundle and cutting the fiber bundle into a predetermined short fiber shape is blended in the polymer. However, the present inventors have examined this method, and found that the binder resin used for bundling the molten liquid crystalline polyester fibers is a biodegradable heavy material that forms the base during kneading to produce a polymer composition or a molded product. It has been found that it acts on a coalescence or a plant-derived polymer to cause deterioration of the polymer, a decrease in molecular weight, and the like, and the physical properties of the resulting polymer composition and molded product are lowered.

Japanese Patent Laid-Open No. 10-273582 JP 2002-69303 A JP 2001-335710 A JP-A-2005-105245

An object of the present invention is to use a bio-derived polymer that has a low environmental impact at the time of disposal and does not depend on petroleum resources and can be repeatedly produced, and has characteristics such as mechanical properties, durability, and heat resistance. It is to provide a method capable of smoothly producing a fiber reinforced polymer composition having excellent workability with good workability and processability.
The object of the present invention is to provide various products excellent in mechanical properties, durability, heat resistance, etc., in particular, fiber reinforced bio-derived polymer compositions capable of smoothly producing electric / electronic components and the polymer compositions. It is providing the molded article which consists of.

In order to achieve the above object, the present inventors have repeatedly studied. As a result, in producing a fiber-reinforced polymer composition by mixing reinforcing fibers with a bio-derived polymer, a short fiber bundle made of molten liquid crystalline polyester fiber is used as the reinforcing fiber. When the constituting single fibers are temporarily bonded to each other by heat fusion on the fiber surface, the short fiber bundle is agglomerated by a hopper or other supply path when supplied to a kneading apparatus such as an extruder or a molding apparatus. It has been found that it flows smoothly without clogging or clogging, and is satisfactorily bitten by the screw of the extruder and is smoothly mixed into the biological polymer.
Furthermore, the present inventors have found that the short fiber bundle in which the molten liquid crystalline polyester short fibers are temporarily bonded to each other by heat fusion on the fiber surface can be satisfactorily opened by heat and / or shear force during kneading. A fiber-reinforced biopolymer composition that is finely dispersed and contained uniformly in a single fiber form without aggregation in a biopolymer composition, and thus has excellent mechanical properties, durability, heat resistance, and the like. It has been found that a molded product can be smoothly produced with good workability without causing clogging in a nozzle or a gate.

Further, the inventors of the present invention preferably use a molten liquid crystalline polyester short fiber bundle having a fiber length of 0.5 to 20 mm from the viewpoints of reinforcing effect, uniform dispersibility in a bio-derived polymer, handleability, and the like. When a molten liquid crystalline polyester long fiber bundle having a tensile strength at 25 ° C. of 15 cN / dtex or more and an initial tensile modulus of 400 cN / dtex or more is cut into short fibers, a biological polymer composition And found that the properties such as mechanical properties, durability and heat resistance of the molded product are improved.
Furthermore, the present inventors can blend the liquid crystalline polyester short fiber bundle in a proportion of 0.5 to 50 parts by mass with respect to 100 parts by mass of the biological polymer. The present inventors have found that it is preferable from the viewpoint of reinforcing effect and the like, and have completed the present invention based on these findings.

That is, the present invention
(1) A method for producing a fiber-reinforced biological polymer composition by blending a short fiber bundle made of molten liquid crystalline polyester fiber into a biological polymer and kneading under heating, comprising a molten liquid crystalline polyester fiber As short fiber bundles, molten liquid crystalline polyester short fibers constituting the short fiber bundle are temporarily bonded to each other by heat fusion with an adhesive strength that separates into individual single fibers by heat and / or shearing force during kneading. It is a manufacturing method of the fiber reinforced bio-derived polymer composition characterized by using the short fiber bundle which is.

And this invention,
(2) The method for producing a fiber-reinforced biological polymer composition according to (1), wherein a fiber length of a short fiber bundle made of molten liquid crystalline polyester fiber is 0.5 to 20 mm in the biological polymer;
(3) A molten liquid crystalline polyester having a tensile strength of 15 cN / dtex or higher and a tensile initial elastic modulus of 400 cN / dtex or higher, in which short fiber bundles made of molten liquid crystalline polyester fibers are temporarily heat-bonded with each other at the fiber surface. (1) or (2) the method for producing a fiber-reinforced biopolymer composition as described above, which is a short fiber bundle obtained by cutting a long fiber bundle into short fibers; and
(4) The fiber-reinforced biological origin of any one of (1) to (3) above, wherein the molten liquid crystalline polyester short fiber bundle is blended at a ratio of 0.5 to 50 parts by mass with respect to 100 parts by mass of the biological polymer. Production method of polymer composition;
It is.

Furthermore, the present invention provides:
(5) The production according to any one of (1) to (4) above, wherein the short fibers made of molten liquid crystalline polyester are spread and dispersed in the form of single fibers in the biological polymer. A fiber reinforced biopolymer composition obtained by the method; and
(6) A molded product produced from the fiber-reinforced biological polymer composition of (5) above;
It is.

In the case of the production method of the present invention, the molten liquid crystalline polyester short fiber bundle in which the molten liquid crystalline polyester short fibers constituting the short fiber bundle are temporarily bonded to each other by thermal fusion on the fiber surface is used as an extruder. When supplying to kneading equipment and molding equipment such as hoppers and other supply channels, they flow smoothly without being agglomerated or clogged, and they are well bitten into the screw of the extruder, making it a fiber-reinforced organism. The derived polymer composition can be smoothly produced with good workability.
In the case of the present invention, the molten liquid crystalline polyester short fiber bundle is well opened by the heat and / or shearing force during kneading when producing the polymer composition and / or the molded article, and the biological weight Kneaded fiber-reinforced bio-derived polymer composition and molded product with excellent physical properties such as mechanical properties, durability, heat resistance, etc. It can be manufactured smoothly with good workability without causing clogging at nozzles and gates in the apparatus and molding apparatus.
In the present invention, when a molten liquid crystalline polyester short fiber bundle having a fiber length of 0.5 to 20 mm is used, the tensile strength at 25 ° C. is 15 cN / dtex or more and the initial tensile elastic modulus is 400 cN / When a melted liquid crystalline polyester long fiber bundle of dtex or higher is cut into short fibers, the mechanical properties, durability, heat resistance, and the like of the biological polymer composition and the molded product are further improved.

In the present invention, when a plant-derived polymer is used as the biological polymer, the carbon dioxide gas generated when the polymer composition of the present invention or a molded product made thereof is incinerated after use is heavy. Since it is used (absorbed) by the plant as a raw material for coalescence at the time of its photosynthesis, the total carbon dioxide gas does not increase in the atmosphere, so it is excellent in ecology.
The fiber-reinforced biopolymer composition of the present invention, a molded product made of the fiber-reinforced polymer composition, and the like are used for electrical and electronic equipment applications such as electrical appliance casings, building materials applications, automotive parts applications, daily necessities applications, medical care, and the like. It can be effectively used for various applications such as applications and agricultural applications.

The present invention is described in detail below.
In the present invention, any of polymers derived from plants, animals or microorganisms can be used as the “biological polymer” that forms the basis of the polymer composition. The biological polymer used in the present invention is a polymer obtained directly from a plant, animal or microorganism as it is (for example, a polymer produced by a plant, animal or microorganism, or a polymer forming the tissue of the organism). It is also possible to produce (produce) a chemical method, a microbiological method, a combination of a chemical method and a microbial method, a physical method, a mechanical method, etc., using a substance derived from the above-mentioned organism as at least a part of the raw material. ) Or any other polymer.

Examples of biological polymers that can be used in the present invention include hydroxycarboxylic acids and dicarboxylic acids such as lactic acid and succinic acid obtained from saccharides contained in plants (eg, corn, moss, sugar cane, etc.) as starting materials. Polylactic acid obtained by using acid, lactic acid copolymer, polybutylene succinate, polyethylene succinate, polyester of butylene succinate and ethylene succinate, and modified products thereof; starch, amylose, cellulose, cellulose Ester, chitin, chitosan, gellan gum, carboxyl group-containing cellulose, carboxyl group-containing starch, pectinic acid, alginic acid and other polysaccharides and modified products thereof; polymers of hydroxybutyrate and / or hydroxyvalerate synthesized by microorganisms Polybetahi Roxyalkanoate, polyhydroxybutyric acid and poly (hydroxybutyric acid / hydroxyhexanoic acid); polyamino acids (polyamides) based on glutamic acid and other amino acids produced by direct fermentation by microorganisms, or modified products thereof Can do.
In the present invention, one or more of the aforementioned polymers can be used as the biological polymer.

Among them, in the present invention, a thermoplastic biological polymer that can be melt-kneaded and melt-molded and is excellent in handleability and molding processability is preferably used as the biological polymer.
Examples of the thermoplastic biological polymer preferably used in the present invention include thermoplastic polyesters (crystalline polyesters) produced using lactic acid and succinic acid obtained from living organisms, and modified products (for example, fats) of the polyesters. Modified products of aliphatic polyols, etc.), bio-derived thermoplastic polyamino acids, modified products of the polyamino acids (for example, modified products of aliphatic polyols, etc.), among which polylactic acid and / or Alternatively, the modified product is more preferably used from the viewpoints of availability, handleability, physical properties and the like.

  When polylactic acid is used as the biological polymer, any of polylactic acid mainly composed of structural units derived from one or both of L-lactic acid and D-lactic acid can be used, and polylactic acid can be used as needed. Other copolymer units (for example, structural units derived from diglycol, dicarboxylic acid, hydroxycarboxylic acid other than lactic acid, lactone, etc.) can be contained.

The molten liquid crystalline polyester forming a short fiber bundle (hereinafter sometimes referred to as “molten liquid crystalline polyester short fiber bundle”) made of molten liquid crystalline polyester fiber used in the present invention has an optical anisotropy (melted) in the molten phase. Polyester exhibiting liquid crystallinity). Whether or not polyester has “melting liquid crystallinity” can be easily known by a known method. For example, a sample (polyester) placed on a hot stage is heated and heated in a nitrogen atmosphere, and the transmitted light is observed. The presence or absence of melted liquid crystallinity can be examined by a method such as
The molten liquid crystalline polyester forming the short bundle of molten liquid crystalline polyester used in the present invention generally has repeating structural units derived from aromatic diol, aromatic dicarboxylic acid, aromatic hydroxycarboxylic acid and the like. As typical examples, there can be mentioned molten liquid crystalline polyesters comprising combinations of repeating structural units shown in the following (1) to (11).

The molten liquid crystalline polyester short fiber bundle used in the present invention may be formed from any of the above-described molten liquid crystalline polyesters (1) to (11), and among them, (5), (8), (9 ) Or (10) and is preferably formed from a molten liquid crystalline polyester comprising a combination of repeating structural units represented by (10), and in particular formed from a molten liquid crystalline polyester comprising a combination of repeating structural units represented by (5) above. More preferably.
When the molten liquid crystalline polyester short fiber bundle is formed from a molten liquid crystalline polyester comprising a combination of repeating structural units represented by (5) above, the proportion of repeating structural units represented by (A) below ( The mechanical properties of the short fiber bundle are such that the ratio of the repeating structural unit represented by B) is formed from a molten liquid crystalline polyester having a molar ratio of (A) :( B) = 96: 4 to 55:45. Further, it is more preferable from the viewpoint that the heat resistance is higher and the water absorption is extremely small, and the reinforcing effect on the biological polymer is further improved.

  The molten liquid crystalline polyester used to form the short bundle of molten liquid crystalline polyester used in the present invention has a melting point of 250 to 350 ° C., particularly 260 to 320 ° C., and a general thermoplastic resin such as polyethylene terephthalate The fiberization equipment in the same temperature range can be used, and when the molten liquid crystalline polyester short fiber bundle used in the present invention is put into the biological polymer and kneaded, the difference from the melting point of the biological polymer is large. From the point of being less susceptible to the effects of heat and the like. The melting point of the molten liquid crystalline polyester referred to in this specification is a melting point measured by a test method based on JIS K7121, and is a differential scanning calorimeter (DSC) [for example, “DSC-60” manufactured by Shimadzu Corporation. ] Is the peak temperature of the main endothermic peak observed.

The molten liquid crystalline polyester short fiber bundle used in the present invention is heated before or at the time when the molten liquid crystalline polyester short fibers constituting the short fiber bundle are supplied to a heating kneading apparatus or a molding apparatus. While maintaining the adhesive state by fusion, when blended with a bio-derived polymer and kneaded under heating, the individual fibers (single filamentary short fibers) are opened by heat and / or shear force during kneading. It is necessary to temporarily bond each other by heat fusion with the adhesive strength to be separated.
In the melted liquid crystalline polyester short fiber bundle, the degree of adhesion by thermal fusion of single fibers is too weak, and the fibers are opened into single fibers before being blended with the biological polymer or when supplied to the kneading device or molding device ( When the product is separated, the bulk increases due to the opening, and when it is supplied to a kneading device such as an extruder or a molding device, it becomes agglomerated or clogged in a hopper or other supply path and flows smoothly. Otherwise, the biting into the screw of the extruder becomes poor, and the workability during the production of the polymer composition or the molded product becomes poor. Moreover, it becomes difficult to mix smoothly and uniformly in the biological polymer, and it is present in the polymer composition or in the molded product as a lump, unevenly distributed, and uniformly dispersed and not contained. This may cause clogging at the nozzle or gate of the molding apparatus, and decrease the mechanical properties, durability, and heat resistance of the resulting polymer composition or molded product.
On the other hand, the degree of heat fusion between single fibers in the melted liquid crystalline polyester short fiber bundle is too strong, and the individual fibers (single fiber-like short fibers) are opened (separated) by heat and / or shearing force during kneading. If not, even if it is easy to supply to a kneading apparatus such as an extruder or a molding apparatus, it remains in a bundle in the biological polymer even after heating and kneading. The reinforcing effect is not sufficiently exhibited, and it becomes difficult to obtain a fiber-reinforced biopolymer composition or a molded product having excellent mechanical properties, durability, heat resistance and the like.

  In the melted liquid crystalline polyester short fiber bundle, “the melted liquid crystalline polyester short fibers constituting the short fiber bundle maintain their melt-bonded state before or during the supply to the heating and kneading apparatus or the molding apparatus, Adhesive strength (thermal fusion strength) that opens (separates) individual single fibers (single filamentary short fibers) by heat and / or shear force during kneading to mix the fiber bundle into the biological polymer ” Is the type of molten liquid crystalline polyester forming the molten liquid crystalline polyester short fiber bundle, the length (fiber length) and thickness (fineness) of the short fiber bundle, and the blending amount of the short fiber bundle into the biological polymer. The kind of the biological polymer, the kneading temperature when the short fiber bundle is mixed in the biological polymer, the magnitude of the shearing force, the kneading time and the like can be adjusted.

  In general, in the present invention, when the melted liquid crystalline polyester short fiber bundle is cut into a short fiber bundle having a length of 5 mm, the “opening rate (no stretching treatment) required by the following method (a)” ”Is 20% or less, particularly 15% or less, and the“ opening ratio (with stretching) ”value obtained by the following method (b) is 70% or more, particularly 80% or more. It is preferable to use a short fiber bundle obtained by cutting a polyester long fiber bundle into a raw fiber bundle (hereinafter sometimes referred to as “raw fabric”) and cutting the molten liquid crystalline polyester long fiber bundle into short fiber shapes. Short fiber bundles obtained by cutting molten liquid crystalline polyester long fiber bundles satisfying the above requirements with the values of “opening rate (without drawing treatment)” and “opening rate (with drawing treatment)” are heated. Before or during supply to a kneading apparatus or molding apparatus, the melt-bonded state is maintained, while individual short fibers are mixed by heat and / or shear force during mixing for mixing the short fiber bundle into the biological polymer. Open (separate) well into fibers (monofilamentary short fibers).

(A) Opening rate (without stretching treatment):
The molten liquid crystalline polyester long fiber bundle is cut into a length of 5 mm, and the molten liquid crystalline polyester short fiber bundle is heated in a constant temperature dryer at 105 ° C. for 2 hours to dry (absolutely dry). 0.15 g (Wa) was sampled and put into a 1000 ml beaker (inner diameter 105 mm) [in the center of the beaker, a stirring peller (stirring blade for a stirrer “Nippon Rika Machinery Co., Ltd.” (50 mm diameter, 3 stainless steel blades) are placed in advance (the distance between the inner bottom surface of the beaker and the lower end of the stirring blade is 15 mm), and 500 ml of distilled water at a temperature of 25 ° C. is put in advance]. The mixture is stirred for 2 minutes under the condition of 600 rpm. After that, the entire contents (water and fibers) in the beaker were transferred to a Buchner funnel with a general imitation paper cut out to a diameter of 11 cm, and the water was separated from the bottom of the Buchner funnel by sucking water with an aspirator. Thereafter, the fibers on the imitation paper are left to dry overnight at room temperature. Next, the fibers on the imitation paper were observed with a microscope, and all the short fiber bundles having a width of 0.3 mm or more were collected with tweezers, and dried for 2 hours by heating in a constant temperature dryer at 105 ° C. for 2 hours. Dried), the mass (Wb) (g) at that time is measured, and the fiber opening rate (without stretching treatment) is determined by the following formula (I-1).

Spreading rate (no stretching treatment) (%) = {(Wa-Wb) / Wa} × 100 (I-1)

(B) Opening rate (with stretching treatment):
(B-1) The melted liquid crystalline polyester long fiber bundle wound around the bobbin before being cut into short fiber bundles was placed on a creel stand and heated to 180 ° C. to a Nelson type roller (R ₁ ) 50 m / guided at a rate, and then the rotation speed by taking up in Nelson type roller of the same type of temperature 25 ° C. was increased by 1.0% than the R ₁ (R _{2), 1} to the molten liquid crystalline polyester filament bundle Apply a stretch of 0.0% and wind up with a winder. By this stretching treatment, the melted liquid crystalline polyester long fiber bundle is subjected to a shearing force for aligning the single fibers by tension, and the thermal fusion between the single fibers is removed by the shearing force.
(B-2) Next, the molten liquid crystalline polyester long fiber bundle subjected to the stretching treatment of the above (b-1) was cut into a 5 mm length to make a short fiber bundle, which was kept in a constant temperature dryer at 105 ° C. for 2 hours. After heating and drying (absolutely dry), 0.15 g (Wc) of the short fiber bundle was collected and stirred in water in the beaker under the same conditions as in (a) above. Transfer the entire contents (water and fiber) to a Buchner funnel with a general imitation paper cut out to a diameter of 11 cm. After separating the water by aspirating water from the bottom of the Buchner funnel, The fiber is left to dry overnight at room temperature. Next, the fibers on the imitation paper were observed with a microscope, and all short fiber bundles having a width of 0.3 mm or more were collected with tweezers, and dried by heating in a constant temperature dryer at 105 ° C. for 2 hours ( (Absolutely dried), the mass (Wd) (g) at that time is measured, and the fiber opening rate (with stretching treatment) is determined by the following mathematical formula (I-2).

Spreading rate (with stretching treatment) (%) = {(Wc−Wd) / Wc} × 100 (I-2)

  The length (fiber length) of the melted liquid crystalline polyester short fiber bundle to be blended with the biological polymer is 0.5 from the viewpoints of handleability, uniform mixing / dispersibility in the biological polymer, and reinforcing effect. It is preferably ˜20 mm, more preferably 1 to 15 mm, and even more preferably 2 to 10 mm. If the fiber length of the melted liquid crystalline polyester short fiber bundle is too short, a sufficient reinforcing effect may not be obtained. On the other hand, if the fiber length is too long, the single fibers are entangled with each other and are difficult to be uniformly mixed and dispersed in the biological polymer. Moreover, the single fiber is likely to be cut during kneading for mixing.

The shape of the molten liquid crystalline polyester short fiber bundle is often a tape shape, but may be a columnar shape in some cases. For this reason, the cross-sectional shape of the melted liquid crystalline polyester short fiber bundle is often deformed rectangular or circular, and the width (diameter) is preferably 50 μm to 10 mm, more preferably 100 μm to 5 mm, and further 200 μm to 3 mm. preferable.
In terms of the fineness (total fineness) of the molten liquid crystalline polyester short fiber bundle, 50 dtex to 1.5 million dtex is preferable, 150 dtex to 500,000 dtex is more preferable, and 500 dtex to 150,000 dtex is further preferable.
When the thickness of the melted liquid crystalline polyester short fiber bundle (diameter or total fineness of the short fiber bundle) is within the above range, the handling property when blended with the biological polymer, the uniform mixing property with the biological polymer, The openability (separability) into single fibers by heat and / or shear during kneading is improved.

The single fiber fineness of each single fiber constituting the melted liquid crystalline polyester short fiber bundle is 0.9 to 50 dtex from the viewpoints of reinforcing effect on the biological polymer, prevention of cutting during kneading, ease of production of the fiber, and the like. It is preferably 1 to 30 dtex, more preferably 1 to 10 dtex.
If the single fiber fineness of each single fiber constituting the melted liquid crystalline polyester short fiber bundle is too small, the fiber shape is damaged at the time of heat-kneading and / or shearing for mixing into the biological polymer, and the fiber is cut. It is difficult to exert a sufficient reinforcing action. On the other hand, if the single fiber fineness is too large, the adhesiveness with the biological polymer is insufficient and the reinforcing action is hardly exhibited.

  The cross-sectional shape of each single fiber constituting the melted liquid crystalline polyester short fiber bundle is not particularly limited. For example, a circular shape, an elliptical shape, a triangular shape, a rectangular shape, a polygonal shape, a flat shape, a multileaf shape, a dogbone shape, a V shape, Any other irregular shape or irregular shape may be used. When the surface area of the short fiber is large, the bonding area with the biological polymer is increased, and the reinforcing effect is improved.

  The short fibers constituting the molten liquid crystalline polyester short fiber bundle may be subjected to a surface treatment, if necessary, in order to improve the affinity with the biological polymer. As the surface treatment method in this case, treatment with a coupling agent such as silane or titanate, ozone or plasma treatment, treatment with an alkyl phosphate ester type surfactant, etc. are effective, but are not limited thereto. Instead, a treatment method that is usually used for surface modification of the filler can be employed.

  The molten liquid crystalline polyester forming the molten liquid crystalline polyester short fiber bundle is a polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, as long as the effects of the present invention are not impaired. Other thermoplastic polymers such as polyester ether ketone and fluororesin, inorganic substances such as titanium oxide, kaolin, silica and barium oxide, colorants such as carbon black, dyes and pigments, antioxidants, UV absorbers, light stabilizers 1 type or 2 types or more of various additives, such as, may be contained.

The method for producing the molten liquid crystalline polyester short fiber bundle used in the present invention is not particularly limited, and the molten liquid crystalline polyester short fibers constituting the short fiber bundle are not separated into single fibers before heating and kneading into a bundle. Any method can be used as long as it can produce short fiber bundles that are bonded to each other by thermal fusion with the adhesive strength that converges and opens (separates) into individual single fibers by heat and / or shear force during kneading. You may manufacture by the method of.
Among them, the molten liquid crystalline polyester short fiber bundle used in the present invention is a fiber bundle composed of molten liquid crystalline polyester long fibers (filaments) (hereinafter sometimes referred to as “molten liquid crystalline polyester long fiber bundle”). After the filaments constituting the long fiber bundle are temporarily bonded to each other on the fiber surface by heat-sealing by heating at an atmospheric temperature 0 to 20 ° C. higher than the solid-state polymerization treatment temperature described later in the production of the By adopting a method of cutting a fiber bundle into short fibers, it can be produced smoothly. In this case, if the heating time is too long, the fibers may be melted by heat, or strong sticking will occur, and when kneaded in the biological polymer, it will not be opened (separated) into a single fiber. Cost. The heat treatment time for adhering (welding) the filaments forming the melted liquid crystalline polyester long fiber bundle may vary depending on the type, melting point, heat treatment temperature, etc. of the melted liquid crystalline polyester forming the long fiber bundle. In general, it is preferably about 30 seconds to 90 minutes, particularly preferably about 1 minute to 60 minutes.
The heat treatment is preferably performed in an inert gas atmosphere such as nitrogen.
Furthermore, this heat treatment is performed in a pressurized atmosphere or in a state where the long fiber bundle is tensioned so that the temporary adhesion by heat fusion between the molten liquid crystalline polyester long fibers constituting the fiber bundle is performed well. You may do it.

  In addition to the above-mentioned method, in which the melted liquid crystalline polyester long fiber bundle is heated in a heating atmosphere and the filaments constituting the long fiber bundle are thermally fused together on the fiber surface to temporarily bond the melted liquid crystalline polyester long fiber bundle. A method may be adopted in which the bundle is heated and pressed with a heat roller and the filaments are temporarily bonded to each other by heat fusion, but if the pressure at the time of heating is too high or the temperature is too high, Reduction, fiber cutting, and complete fusion of fibers (filaments) occur. Therefore, it is necessary to control the heating temperature and the fusion force (pressure) so that these problems do not occur.

The method for producing the above-mentioned molten liquid crystalline polyester long fiber bundle before the heat treatment used for the production of the molten liquid crystalline polyester short fiber bundle is not particularly limited, and the molten liquid crystalline polyester is filamented from the spinneret of the die as in the prior art. It can be produced by melt spinning into a shape (long fiber shape) and converging a plurality of melt spun filaments. The melted liquid crystalline polyester long fiber bundle obtained in this way is excellent in mechanical performance and thermal performance by itself, and particularly has dimensional stability. Therefore, the filaments constituting the long fiber bundle are temporarily put together. It can be subjected to the above-mentioned heat treatment for adhesion by thermal fusion, but it can be used after further solid phase polymerization after melt discharge-bundling to further improve the mechanical properties. This is preferable because the effect and the effect of improving heat resistance are further enhanced.
Solid phase polymerization of a melt liquid crystalline polyester long fiber bundle obtained by melt spinning is performed in an inert gas atmosphere such as nitrogen gas, an active gas atmosphere containing oxygen such as air, or under reduced pressure. The fiber bundle is preferably heated to a temperature within the range of [melting point−60 ° C.] to [melting point + 10 ° C.] of the molten liquid crystalline polyester forming the long fiber bundle. This solid phase polymerization treatment is preferably performed before the long fiber bundle is cut into short fiber bundles, but may be performed after being cut into short fiber bundles in some cases.
By performing such solid-phase polymerization treatment, the solid-phase polymerization of the melted liquid crystalline polyester forming the fiber is promoted, the molecular weight is increased, the mechanical properties of the fiber are improved, and the heat resistance is improved by increasing the melting point or making it infusible. Can be achieved.

  The melt-liquid crystalline polyester long fiber bundle subjected to the solid phase polymerization described above, and the filament constituting the long fiber bundle by heat-treating the long fiber bundle after the solid phase polymerization at a temperature higher than the melting point of the melt liquid crystalline polyester The melted liquid crystalline polyester long fiber bundle temporarily bonded to each other by heat fusion generally has a tensile strength of 15 cN / dtex or more at 25 ° C. and a tensile initial elastic modulus of 400 cN / dtex or more, Excellent mechanical properties and heat resistance. Therefore, when producing the biopolymer composition of the present invention using a molten liquid crystalline polyester short fiber bundle obtained by cutting the molten liquid crystalline polyester long fiber bundle having the tensile strength and tensile initial elastic modulus into short fibers, When the molten liquid crystalline polyester short fiber bundle is blended into the biological polymer and kneaded and / or molded under heating in a mixing apparatus or molding apparatus, melting of the molten liquid crystalline polyester short fiber, collapse of the fiber form, It is possible to obtain a biological polymer composition and a molded article that are more effectively prevented from lowering the physical properties of the fiber and are further excellent in mechanical properties and heat resistance.

  In particular, it consists of the repeating structural units (A) and (B) shown in the above [Chemical Formula 3], and the molar ratio of [repeating structural unit (A)]: [repeating structural unit (B)] is 96: 4. The long fiber bundle after solid phase polymerization formed from a melt liquid crystalline polyester having a molecular weight of ˜55: 45 generally has a tensile strength of 20 cN / dtex or more and a tensile modulus of 450 cN / dtex or more at 25 ° C. In the present invention, it is obtained from the molten liquid crystalline polyester long fiber bundle as a molten liquid crystalline polyester short fiber bundle because it has extremely high mechanical properties and is extremely excellent in heat resistance and non-water absorption. When a molten liquid crystalline polyester short fiber bundle is used, a biological polymer composition and a molded product that are extremely excellent in properties such as mechanical properties and heat resistance can be obtained.

In producing the melted liquid crystalline polyester short fiber bundle used in the present invention, a smoothing agent, an antistatic agent (organic interface) is used as necessary in order to improve process passability and prevent fiber damage due to abrasion with a guide or the like. A treatment agent such as a general oil containing an active agent component and other components may be applied to the fiber surface. However, the treatment agent applied to the fiber surface is thermally decomposed during the heat-kneading of the molten liquid crystalline polyester short fiber and the biological polymer to cause degradation of the biological polymer, and the biological polymer composition or molded product Since appearance quality, mechanical properties, and the like may be lowered, it is desirable to reduce the amount of treatment agent applied, generally 1.5% by mass or less based on the mass of the molten liquid crystalline polyester fiber, particularly 0.2 to It should be about 1.3% by mass.
The treatment agent is applied to the fiber surface during the production of a melted liquid crystalline polyester long fiber bundle before being cut into short fibers, during the solid phase polymerization of the melted liquid crystalline polyester long fiber bundle, When a heat treatment for temporarily adhering the filaments forming the fiber to each other by thermal fusion, when cutting a molten liquid crystalline polyester long fiber bundle into short fibers, a molten liquid crystalline polyester short fiber bundle into a biological polymer It may be carried out at any stage such as when blending.

  A molten liquid crystalline polyester short fiber bundle in which short fibers are temporarily bonded by thermal fusion is blended with a biological polymer, kneaded under heating, and melted by the temperature and / or shearing force during heating and kneading. Fiber-reinforced polyester-derived short fiber bundles are opened (separated) into short fibers, and the melted liquid crystalline polyester short fibers are in the form of single fibers mixed and dispersed in biological polymers. A polymer composition is produced.

The amount of molten liquid crystalline polyester short fiber bundle is determined by the dispersibility of the molten liquid crystalline polyester short fibers in the biological polymer, the mechanical properties of the resulting biological polymer composition and molded product, heat resistance, and dimensional stability. From the viewpoint of moldability at the time of injection property and injection molding, it is preferably 0.5 to 50 parts by mass, more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the biological polymer. More preferably, it is 1-20 mass parts.
If the amount of the melted liquid crystalline polyester short fiber bundle is too small, it will be difficult to obtain a sufficient reinforcing effect by the melted liquid crystalline polyester short fiber, while if the amount is too large, the melted liquid crystallinity in the biological polymer will be lost. The dispersibility of the polyester short fiber is deteriorated, and the workability in producing the polymer composition, the appearance defect of the obtained biopolymer composition or the molded product, and the deterioration of the mechanical properties are likely to occur.

When blending molten liquid crystalline polyester short fiber bundles with a biological polymer, the molten liquid crystalline polyester is sufficiently dried to prevent the biological polymer from being decomposed by moisture during heating and kneading. It is desirable to use short fiber bundles. In general, the drying treatment of the molten liquid crystalline polyester short fiber bundle for removing water is preferably performed at 140 ° C. or lower. If the drying temperature is too high, the fibers are strongly heat-sealed in the short fiber bundle, and are not opened (separated) into a single fiber during heating and kneading.
In the melt liquid crystalline polyester fiber used in the present invention, the polymer molecules are mainly formed from hydrophobic structural units, and the fiber structure is dense and has no voids such as voids. Very low. From this point, the drying treatment of the molten liquid crystalline polyester short fiber bundle for removing moisture can be easily performed, and the molten liquid crystalline polyester short fiber bundle after the drying treatment contains almost no moisture. The water released from the fibers when blended with the biological polymer and heat-kneaded is extremely small, and the adverse effects such as decomposition and deterioration of the biological polymer due to the water during heat-kneading and thermoforming are extremely small.

In producing the biological polymer composition of the present invention, the method of blending the molten liquid crystalline polyester short fiber bundle with the biological polymer and the heat-kneading method are not particularly limited, and the type of the biological polymer, melting What is necessary is just to employ | adopt an appropriate method according to the compounding quantity of a liquid crystalline polyester short fiber bundle, the use of a biological origin polymer composition, etc.
In addition, a molten liquid crystalline polyester short fiber bundle is blended into a biological polymer and heated and kneaded to once produce a fiber reinforced biological polymer composition in a pellet form or other suitable form, and then the fiber reinforced biological fiber. Various products such as molded products may be produced using the combined composition, or a product such as molded products may be used as it is by blending a melt-liquid crystalline polyester short fiber bundle with a biological polymer and kneading and molding. You may manufacture directly.
The heating and kneading operation for producing the fiber-reinforced biological polymer composition can be performed using a known mixing or kneading apparatus such as a kneader-luder, an extruder, a mixing roll, or a Banbury mixer.

  In the production of the fiber-reinforced biological polymer composition of the present invention, within the range that does not impair the effects of the present invention, together with the biological polymer, if necessary, other polymers such as polymers derived from petroleum-based resources. A polymer may be mixed. Examples of other polymers include thermoplastic polymers such as polyethylene, polypropylene, polystyrene, ABS, nylon, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, urea resin, melamine resin, alkyd resin, acrylic resin, unsaturated polyester resin Diallyl phthalate resin, epoxy resin, silicone resin, cyanate resin, furan resin, ketone resin, xylene resin, thermosetting polyimide, thermosetting polyamide, styrylpyridine resin, nitrile terminal type resin, addition curable quinoxaline, Examples thereof include thermosetting resins such as addition-curable polyquinoxaline resins, alloys of the thermoplastic polymers or thermosetting resins and biological polymers. When a thermosetting resin is used in combination, a curing agent and a curing accelerator necessary for the curing reaction can be used.

  Further, in the production of the fiber-reinforced biopolymer composition of the present invention, if necessary, inorganic fillers, fiber reinforcing materials other than molten liquid crystalline polyester fibers, colorants (such as titanium oxide), stabilizers (radicals). Scavengers, antioxidants, etc.), flame retardants (metal hydrates, halogen flame retardants, phosphorus flame retardants, etc.), known crystal nucleating agents (talc, etc.), antibacterial agents, fungicides, etc. can be used in combination. In that case, examples of the inorganic filler include silica, alumina, sand, clay, and iron, and examples of the reinforcing material include acicular inorganic substances. Moreover, as said antibacterial agent, a silver ion, a copper ion, or the zeolite containing these can be used, for example.

In either case where a fiber-reinforced biological polymer composition is once produced and then a molded product is produced using the composition, or when a fiber-reinforced biological polymer composition is produced and molded simultaneously, Molding can be performed using a conventionally known molding method or molding processing apparatus, for example, any molding such as extrusion molding, injection molding, compression molding, blow molding, calendar molding, vacuum molding, foam molding, etc. It can be molded by a processing method, and can be melt-spun to produce a fiber. As a result, it is possible to obtain a molded product of an arbitrary form such as a sheet, a film, a pipe, a mold, a laminate, a fiber, a fiber product, and the like. It can be used for electrical and electronic equipment applications such as body, building material applications, automotive parts applications, daily necessities applications, medical applications, and agricultural applications.
In particular, when the biological polymer is polylactic acid or other thermoplastic biological polymer, the fiber-reinforced biological polymer composition of the present invention is used to make a conventional thermoplastic polymer. By adopting various melt molding methods that are widely used, electrical and electronic equipment products and other various products can be manufactured easily and smoothly. In the case of performing melt molding, the molding temperature may be set to a temperature that is not less than the melting temperature of the biological polymer and the molten liquid crystalline polyester fiber or biological polymer is not thermally deteriorated.

Hereinafter, the present invention will be described more specifically with reference to examples and the like, but the present invention is not limited to the following examples.
In the following examples, various physical properties, workability, performance, and the like were evaluated as follows.

(1) Weight average molecular weight (Mw) and number average molecular weight (Mn) of polylactic acid:
(I) Molecular weight of polylactic acid used as a raw material for producing the polylactic acid composition:
Using a solution obtained by dissolving 10 mg of polylactic acid used in the production of the polylactic acid composition in 5 g of chloroform, using a gel permeation chromatograph (GPC) [“Prominence GPC system” manufactured by Shimadzu Corporation], a chloroform solvent Was used to measure the weight average molecular weight (Mw) and number average molecular weight (Mn) of polylactic acid in terms of polystyrene.
(Ii) Molecular weight of polylactic acid in the molded product:
Each molded product (test piece) obtained in the following examples (Examples 1 and 2 and Comparative Examples 1 to 3) is dissolved in chloroform, and insoluble in the liquid crystal polyester short fibers containing the melted liquid crystal polyester short fibers. Using a filtrate obtained by filtering short fibers and dissolving polylactic acid, a gel permeation chromatograph (GPC) ["Prominence GPC system" manufactured by Shimadzu Corporation] and using a chloroform solvent Then, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polylactic acid in terms of polystyrene were measured.

(2) Melting point (° C.) and melt viscosity (Pa · s) of melted liquid crystalline polyester used for fiber production:
(I) Melting point (° C) of molten liquid crystalline polyester:
After taking 10-20 mg of molten liquid crystalline polyester sample and sealing it in an aluminum pan, a differential scanning calorimeter (DSC) [“DSC-60” manufactured by Shimadzu Corporation] is used and nitrogen gas is used as a carrier gas. Was injected at a flow rate of 100 ml / min, and the endothermic peak temperature when the temperature was raised at a rate of temperature rise of 20 ° C./min was measured (1st Run) to obtain the melting point (° C.).
Depending on the type of polymer, a clear endothermic peak may not appear at 1st Run. In that case, the temperature is increased to 50 ° C. higher than the expected melting point at a rate of temperature increase of 50 ° C./min. Then, hold at that temperature for 3 minutes or more and completely dissolve, then cool to 50 ° C. at a temperature lowering rate of 50 to 80 ° C./min, and then measure an endothermic peak at a temperature rising rate of 20 ° C./min. ° C).
(Ii) Melt viscosity (Pa · s) of molten liquid crystalline polyester:
The melt viscosity (Pa · s) of the molten liquid crystalline polyester was measured under the conditions of a melting temperature of 300 ° C. and a shear rate of 1000 sec ⁻¹ using “Capillograph 1B type” manufactured by Toyo Seiki Co., Ltd.

(3) Tensile properties (tensile strength, initial tensile modulus and tensile elongation) of melted liquid crystalline polyester long fiber bundle:
Production Example 1 (2), Production Example 2 (1), Production Example 3 (2), Production Example 4 (2), Production Example 7 (1), Production Example 8 (1) and Each of the molten liquid crystalline polyester long fiber bundles obtained after the heat treatment obtained in (1) of Production Example 9 was tested using a universal material testing machine 4301 manufactured by Instron in accordance with JIS L1013 test method. Tensile strength, initial tensile modulus, and tensile elongation were measured under the conditions of a length of 20 cm, an initial load of 0.1 g / dtex, and a tensile speed of 10 cm / min. The same test was performed 5 times, and the average value was taken and adopted as tensile strength (cN / dtex), initial tensile modulus (cN / dtex) and tensile elongation (%).

(4) Opening rate when a melted liquid crystalline polyester long fiber bundle (raw fabric) is cut into a short fiber bundle having a length of 5 mm:
For each of the melted liquid crystalline polyester long fiber bundles (raw fabrics) obtained in the following Production Examples 1 to 9 before being cut into short fiber bundles, the “(a) fiber opening rate (no stretching treatment)” described above. The same operation as described in the section is performed to obtain the “opening rate (no stretching treatment)” (%) by the above formula (I-1) and the above-mentioned “(b) opening rate ( The same operation as described in the section “With stretching treatment” was performed, and “Opening rate (with stretching treatment)” (%) was obtained by the above-described equation (I-2).
As described above, the melt liquid crystalline polyester short fiber bundle used in the present invention has a “opening ratio (no stretching treatment)” obtained by the above-described method (a) of 20% or less, particularly 15% or less. In addition, a melted liquid crystalline polyester long fiber bundle (raw fabric) having an “opening ratio (with stretching treatment)” required by the method (b) of 70% or more, particularly 80% or more, is cut into short fibers. It is preferable that it is a short fiber bundle obtained as described above.

(5) Cohesiveness of molten liquid crystalline polyester short fiber bundle or short fiber:
Production Example 1 (3), Production Example 2 (2), Production Example 3 (3), Production Example 4 (3), Production Example 5, Production Example 6, Production Example 8 (2) and 20 g of each of the molten liquid crystalline polyester short fiber bundle obtained in (2) of Production Example 9 and the unfocused molten liquid crystalline polyester short fiber obtained in (2) of Production Example 7 has an opening of 1 cm square. Place it flatly on a circular sieve (diameter 20cm), add 20cm of shaking up and down 1cm at a shaking speed of 1 time / sec. The mass of short fibers (total mass of bundled and monofilamentary short fibers) (g) was measured, and the ratio (mass of molten liquid crystalline polyester short fibers remaining on the sieve from the following formula (II) %) As an index of cohesion.

Aggregability (mass%) = {mass of short fibers remaining on the sieve (g) / sample amount (20 g)} × 100 (II)

It shows that it is easy to aggregate (it is easy to form a dama), so that there are many ratios (mass%) of the molten liquid crystalline polyester short fiber which remains on a sieve.

(6) Flowability of molten liquid crystalline polyester short fiber bundle or short fiber:
Production Example 1 (3), Production Example 2 (2), Production Example 3 (3), Production Example 4 (3), Production Example 5, Production Example 6, Production Example 8 (2) and Each of the molten liquid crystalline polyester short fiber bundle obtained in (2) of Production Example 9 and the unfocused molten liquid crystalline polyester short fiber obtained in (2) of Production Example 7 was charged at a charging speed (input per unit time). From a top opening of a conical hopper to a tapered tubular conical hopper (inner diameter of the upper opening 14 cm, inner diameter of the lower opening 4 cm, height 15 cm) Continuously throwing vertically downward from an upper position about 10 cm away, and measuring the upper feeding speed (amount charged per unit time) at which a melted liquid crystalline polyester short fiber bundle or short fiber can pass without blocking the hopper Liquidity indicators and It was.

(7) Bending strength and flexural modulus of test piece (molded product):
About the test piece (molded article) manufactured in the following Examples 3 to 15 and Comparative Examples 4 to 6, using a material testing machine [“Autograph AG / R” manufactured by Shimadzu Corporation], JIS K 7171 Based on the test method, the bending strength and the flexural modulus were measured. The measurement conditions were a distance between fulcrums of 50 mm and an indenter push speed of 1.6 mm / min.

(8) Impact resistance of test piece (molded product):
About the test piece (molded article) manufactured in the following Examples 3 to 15 and Comparative Examples 4 to 6, an impact tester ["JISL-D" manufactured by Toyo Seiki Seisakusho Co., Ltd.] was used. In accordance with the law, the Izod impact strength of the notched specimen was measured. In addition, the test piece used here is a molded product based on No. 2 type A test piece, with a notch (d = 2.54 mm, r = 0.25 mm), length l (L) of 64 mm, width b is about 3.2 mm, and thickness t is about 10.3 mm.

(9) Heat resistance of test piece (molded product):
About the test piece (molded article) manufactured in the following Examples 3 to 15 and Comparative Examples 4 to 6, using an HTD / VSPT measuring device [“TM-4126” manufactured by Ueshima Seisakusho Co., Ltd.], JIS K 7191 -2 The deflection temperature under load (HDT) was measured according to the test method. The measurement conditions were a load of 1.8 MPa, a temperature increase rate of 2 ° C./min, and a fulcrum distance of 100 mm. The HDT measured in this way was used as an index of heat resistance.

<< Production Example 1 >> [Production of Molten Liquid Crystalline Polyester Short Fiber Bundle (a ₁ )]
(1) Molten liquid crystalline polyester having a recurring structural unit (A) :( B) molar ratio of 73:27 shown in the above [Chemical Formula 3] [“Vectra A” manufactured by Polyplastics Co., Ltd.) ( (Melting point = 281 ° C., melt viscosity = 42.5 Pa · s) is supplied to the melt spinning apparatus, discharged from the die at a spinning temperature of 305 ° C. to form a yarn, and taken up by a rotating roller at a speed of 1000 m / min. The yarn was wound with a winder to produce a spinning yarn having a fineness of 1670 dtex / 600 filament (filament single fiber fineness of 2.8 dtex).
(2) The spinning yarn obtained in (1) above is turned over to a stainless steel bobbin for solid-phase polymerization and treated in a nitrogen gas atmosphere at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours. After that, a melted liquid crystalline polyester long fiber bundle in which single fibers (filaments) are temporarily bonded by thermal fusion by heat treatment at 290 ° C. for 30 minutes (the cross section of the long fiber bundle has a thickness of about 0.1 mm). , Width about 2 mm).
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 23 cN / dtex, the initial tensile modulus was 525 cN / dtex, and the tensile elongation was 4.0. %Met.
Moreover, when the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the obtained melt liquid crystalline polyester long fiber bundle (raw fabric) after heat treatment was measured by the method described above, It was as shown in Table 1 below.
(3) The molten liquid crystalline polyester long fiber bundle after heat treatment obtained in the above (2) is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [“molten liquid crystal The short polyester fiber bundle (a ₁ ) ”was produced.
The cohesiveness and fluidity of the melted liquid crystalline polyester short fiber bundle (a ₁ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

<< Production Example 2 >> [Production of Molten Liquid Crystalline Polyester Short Fiber Bundle (a ₂ )]
(1) The spinning yarn obtained in (1) of Production Example 1 was turned over to a stainless steel bobbin for solid-phase polymerization, and in a nitrogen gas atmosphere at 250 ° C. for 6 hours and then at 275 ° C. Treated for 10 hours. Thereafter, six solid phase polymerized yarns were prepared on a creel frame, and the six yarns were aligned to form a 10020 dtex / 3600f yarn, which was wound around a stainless steel bobbin. Next, this bobbin was heat-treated at 290 ° C. for 60 minutes in a nitrogen gas atmosphere, and a melted liquid crystalline polyester long fiber bundle (long fiber bundle cross-sectional thickness of about 0) was obtained by temporarily adhering long fibers to each other by heat fusion. 0.5 mm, width of about 4 mm).
When the tensile properties of the melted liquid crystalline polyester long fiber bundle thus obtained were measured by the above method, the tensile strength was 23 cN / dtex, the initial tensile modulus was 510 cN / dtex, and the tensile elongation was 3.9. %Met.
Moreover, when the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the obtained melt liquid crystalline polyester long fiber bundle (raw fabric) after heat treatment was measured by the method described above, It was as shown in Table 1 below.
(2) The molten liquid crystalline polyester long fiber bundle after the heat treatment obtained in the above (1) is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [“molten liquid crystal The short polyester fiber bundle (a ₂ ) ”was produced.
The cohesiveness and fluidity of the molten liquid crystalline polyester short fiber bundle (a ₂ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

<< Production Example 3 >> [Production of Molten Liquid Crystalline Polyester Short Fiber Bundle (a ₃ )]
(1) Supply the same molten liquid crystalline polyester used in (1) of Production Example 1 to the same melt spinning apparatus used in (1) of Production Example 1, and discharge from the die at a spinning temperature of 305 ° C. The yarn was made into a yarn, taken up with a rotating roller at a speed of 1000 m / min, and taken up with a take-up machine, and a spinning original yarn having a fineness of 510 dtex / 300 filament (filament single fiber fineness of 1.7 dtex) was collected. .
(2) In the same manner as in Production Example 1 (2), the spinning yarn obtained in (1) above was rolled back onto a stainless steel bobbin to perform a solid phase polymerization treatment, and in a nitrogen gas atmosphere, After a solid state polymerization treatment at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours, the melted liquid crystalline polyester is obtained by subsequently heat-treating at 290 ° C. for 30 minutes and temporarily bonding the single fibers (filaments) by thermal fusion. A fiber bundle (the cross section of the long fiber bundle has a thickness of about 0.1 mm and an array number of about 0.5 mm) was produced.
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 25 cN / dtex, the initial tensile modulus was 530 cN / dtex, and the tensile elongation was 4.0. %Met.
Moreover, when the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the obtained melt liquid crystalline polyester long fiber bundle (raw fabric) after heat treatment was measured by the method described above, It was as shown in Table 1 below.
(3) The molten liquid crystalline polyester long fiber bundle after heat treatment obtained in the above (2) is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [“molten liquid crystal The short polyester fiber bundle (a ₃ ) ”was produced.
The cohesiveness and fluidity of the molten liquid crystalline polyester short fiber bundle (a ₃ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

<< Production Example 4 >> [Production of Molten Liquid Crystalline Polyester Short Fiber Bundle (a ₄ )]
(1) Supply the same molten liquid crystalline polyester used in (1) of Production Example 1 to the same melt spinning apparatus used in (1) of Production Example 1, and discharge from the die at a spinning temperature of 305 ° C. The yarn was made into a yarn, taken up with a rotating roller at a speed of 1000 m / min, and taken up with a winder, and a spinning yarn having a fineness of 1670 dtex / 300 filament (filament single fiber fineness of 5.6 dtex) was collected. .
(2) In the same manner as in Production Example 1 (2), the spinning yarn obtained in (1) above was rolled back onto a stainless steel bobbin to perform a solid phase polymerization treatment, and in a nitrogen gas atmosphere, After a solid phase polymerization treatment at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours, and then heat treatment at 295 ° C. for 1 hour, the melted liquid crystalline polyester in which the single fibers (filaments) are temporarily bonded by thermal fusion A fiber bundle (the cross section of the long fiber bundle has a thickness of about 0.1 mm and a width of about 2 mm) was produced.
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 23.5 cN / dtex, the initial tensile modulus was 520 cN / dtex, and the tensile elongation was 4 0.0%.
Moreover, when the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the obtained melt liquid crystalline polyester long fiber bundle (raw fabric) after heat treatment was measured by the method described above, It was as shown in Table 1 below.
(3) The molten liquid crystalline polyester long fiber bundle after heat treatment obtained in the above (2) is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [“molten liquid crystal The short polyester fiber bundle (a ₄ ) ”was produced.
The cohesiveness and fluidity of the molten liquid crystalline polyester short fiber bundle (a ₄ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

"Production Example 5-6" Production of liquid crystalline polyester short fiber bundles (a ₅₎ and (a _6)]
The molten liquid crystalline polyester long fiber bundle after heat treatment obtained in (2) of Production Example 1 is cut into a length of 1 mm with a cutter blade (Production Example 5) or cut into a length of 6 mm (Production Example). 6) a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 1 mm [referred to as “molten liquid crystalline polyester short fiber bundle (a ₅ )”] and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 6 mm [“melted liquid crystalline polyester Short fiber bundle (referred to as “a ₆ ”) ”was manufactured.
When the cohesiveness and fluidity of the melted liquid crystalline polyester short fiber bundles (a ₅ ) and (a ₆ ) thus obtained were examined by the methods described above, they were as shown in Table 1 below.

<< Production Example 7 >> [Production of Melt Liquid Crystalline Polyester Short Fiber (b)]
(1) In Production Example 1 (2), the solid-phase polymerization of the melted liquid crystalline polyester long fiber bundle was completed in a nitrogen gas atmosphere at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours ( Except that the final heat treatment at 290 ° C. was not performed), the same operations as in Production Example 1 (1) and (2) were performed, and the melted liquid crystal properties in which the single fibers (filaments) were not thermally fused together A polyester long fiber bundle (1670 dtex / 600f) was produced.
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 23 cN / dtex, the initial tensile modulus was 525 cN / dtex, and the tensile elongation was 4.0. %Met.
Moreover, when the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the obtained melt liquid crystalline polyester long fiber bundle (raw fabric) after heat treatment was measured by the method described above, It was as shown in Table 1 below.
(2) The heat-treated molten liquid crystalline polyester long fiber bundle obtained in (1) above is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber having a fiber length of 3 mm ["melted liquid crystalline polyester" Short fiber bundle (b) ".
The cohesiveness and fluidity of the molten liquid crystalline polyester short fiber (b) thus obtained were examined by the method described above, and as shown in Table 1 below.

<< Production Example 8 >> [Production of Molten Liquid Crystalline Polyester Short Fiber (c ₁ )]
(1) In Production Example 1 (2), the solid-phase polymerization of the melted liquid crystalline polyester long fiber bundle was completed in a nitrogen gas atmosphere at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours ( A melt liquid crystalline polyester long fiber bundle (1670 dtex) in which the single fibers (filaments) are not bonded to each other by performing the same operation as in (2) of Production Example 1 except that the final heat treatment at 290 ° C. was not performed. / 600f).
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 23 cN / dtex, the initial tensile modulus was 530 cN / dtex, and the tensile elongation was 4.0. %Met.
(2) Ten bobbins of a melted liquid crystalline polyester long fiber bundle after heat treatment in which the single fibers obtained in (1) above are not bonded to each other are placed on a creel table, pulled out from the bobbin, and converged by a guide 1 After forming the yarn, the yarn is introduced into the emulsion liquid (solid content concentration 9% by mass) of the polyurethane resin (Dainippon Ink Chemical Co., Ltd. “Bondic 2220”), and the yarn is impregnated with the polyurethane resin emulsion liquid. Next, the excess adhering liquid was squeezed with a mangle equipment, dried in a hot air drier at 130 ° C., and a melted liquid crystalline polyester long fiber bundle adhered with a polyurethane resin [thickness (diameter) 1.0 mm of the long fiber bundle]. Manufactured. At this time, the adhesion amount of the polyurethane resin was 7 parts by mass with respect to 100 parts by mass of the fiber.
The “opening rate (without stretching treatment)” and “opening rate (with stretching treatment)” of the melted liquid crystalline polyester long fiber bundle (raw fabric) after adhesion of the polyurethane resin thus obtained were measured by the method described above. However, it was as shown in Table 1 below.
(3) The molten liquid crystalline polyester long fiber bundle after the polyurethane resin treatment obtained in (2) is cut into a length of 3 mm with a cutter blade, and a molten liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [" A molten liquid crystalline polyester short fiber bundle (c ₁ ) ”was produced.
The cohesiveness and fluidity of the melted liquid crystalline polyester short fiber bundle (c ₁ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

<< Production Example 9 >> [Production of Melt Liquid Crystalline Polyester Short Fiber (c ₂ )]
(1) In Production Example 1 (2), the solid-phase polymerization of the melted liquid crystalline polyester long fiber bundle was completed only by heat treatment in a nitrogen gas atmosphere at 250 ° C. for 6 hours and then at 275 ° C. for 10 hours ( Except that the final heat treatment at 290 ° C. was not performed), the same operations as in Production Example 1 (1) and (2) were performed, and the melted liquid crystal properties in which the single fibers (filaments) were not thermally fused together A polyester long fiber bundle (1670 dtex / 600f) was produced.
When the tensile properties of the melted liquid crystalline polyester long fiber bundle obtained by this treatment were measured by the method described above, the tensile strength was 23 cN / dtex, the initial tensile modulus was 530 cN / dtex, and the tensile elongation was 4.0. %Met.
(2) Ten bobbins of the melted liquid crystalline polyester long fiber bundle after heat treatment in which the single fibers obtained in the above (1) are not thermally fused are placed on a creel table, pulled out from the bobbin, and converged by a guide. Into one yarn, and then introduced into an emulsion solution (solid concentration 40% by mass) of polylactic acid resin ("Terramac LAE-013N" manufactured by Unitika Ltd.) to impregnate the yarn with polylactic acid resin emulsion solution. Next, the excess adhering liquid was squeezed out with a mangle equipment, dried in a hot air dryer at 130 ° C., and bonded with a polylactic acid resin [long fiber bundle thickness (diameter) 1. 1 mm] was produced. At this time, the adhesion amount of the polylactic acid resin was 28 parts by mass with respect to 100 parts by mass of the fiber.
Measure the "opening rate (without stretching treatment)" and "opening rate (with stretching treatment)" of the molten liquid crystalline polyester long fiber bundle (raw fabric) after adhesion of the polylactic acid resin obtained by the above method. As a result, it was as shown in Table 1 below.
(3) The melted liquid crystalline polyester long fiber bundle after the polylactic acid resin treatment obtained in (2) is cut into a length of 3 mm with a cutter blade, and a melted liquid crystalline polyester short fiber bundle having a fiber bundle length of 3 mm [ “Fused liquid crystalline polyester short fiber bundle (c ₂ )” was produced.
The cohesiveness and fluidity of the molten liquid crystalline polyester short fiber bundle (c ₂ ) thus obtained were examined by the method described above, and as shown in Table 1 below.

As can be seen from the results in Table 1 above, in the melted liquid crystalline polyester short fiber bundles (a ₁ ) to (a ₆ ) of Production Examples 1 to ₆ , the short fibers forming the short fiber bundle are thermally fused to each other. A melted liquid crystalline polyester long fiber bundle (raw fabric) having a small value of “opening rate (without stretching treatment)” and a large value of “opening rate (with stretching treatment)”. Therefore, in the initial stage of handling, there is no generation of lumps, clogging in a feeding device such as a hopper does not occur, fluidity and handling are excellent, and stirring, mixing, and kneading At the advanced stage, the temporary adhesion is eliminated, and the single fibers are well separated and opened.
Further, the melted liquid crystalline polyesters of Production Examples 8 to 9 obtained by cutting a melted liquid crystalline polyester long fiber bundle (raw fabric) in which fibers are bonded with an adhesive (polyurethane resin or polylactic acid resin) into short fibers. In the short fiber bundles (c ₁ ) to (c ₂ ), the short fibers in the short fiber bundle are bonded to each other by an adhesive, so that the cohesiveness is low and the fluidity is almost high.
On the other hand, the melted liquid crystalline polyester short fiber bundle (b) of Production Example 7 has no cohesion between the short fibers, so that the cohesiveness is large and lumps are generated, and the fluidity in a feeding device such as a hopper is obtained. Is bad.

<< Examples 1-2 and Comparative Examples 1-3 >>
(1) 5 parts by mass of each of the molten liquid crystalline polyester short fiber bundles or the unfocused molten liquid crystalline polyester short fibers obtained in Production Examples 1 and 2 and 7 to 9 was mixed with polylactic acid (TE-4000 manufactured by Unitika Ltd.). After premixing with 95 parts by mass of Mw (about 130,000, Mn about 70,000) pellets (cylindrical pellets having a diameter of about 2 mm and a length of 4 mm), this mixture was provided in a co-directional twin-screw extrusion kneader. It is continuously fed at a feed rate of 1 kg / h from a tapered tubular conical hopper (the inner diameter of the upper opening is 14 cm, the inner diameter of the lower opening is 4 cm, and the height is 15 cm), kneaded at 190 ° C, extruded into a strand, and cut And the pellet of the polylactic acid composition containing a melt liquid crystalline polyester short fiber was manufactured.
During the manufacturing operation of the polylactic acid composition pellets, in order to investigate the stability of the kneading operation, the hopper (input port) of the kneading machine is blocked by short fiber bundles or short fibers and the operation is interrupted per hour. When the average value of was measured, it was as shown in Table 2 below.
(2) The pellet of the polylactic acid composition obtained in the above (1) was 0.75 mm using an injection molding machine under the conditions of an injection pressure of 100 MPa and a barrel and nozzle temperature of 190 ° C. It was injection-molded into a mold (plate thickness 1.6 mm × length 80 mm × width 12 mm) equipped with a pin gate having a diameter. In order to investigate the dispersibility of the melted liquid crystalline polyester short fibers in polylactic acid, this injection molding was performed 100 times (100 shots), and the number of gate cloggings was counted, as shown in Table 2 below. there were.
Moreover, when the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polylactic acid in the molded article (test piece) obtained by this were measured by the above method, they were as shown in Table 1 below. .

As seen from the results in Table 2 above, in Examples 1-2 and Comparative Examples 2-3, molten liquid crystals in which short fibers are temporarily bonded to each other by heat fusion or an adhesive (polyurethane resin or polylactic acid resin). A polylactic acid composition is produced by mixing a bundle of short polyester fiber fibers with polylactic acid, and molding is performed using the polylactic acid composition, so that a liquid crystal melted during kneading and extrusion when producing the polylactic acid composition. The short polyester fiber can be smoothly supplied to the kneader without clogging with the hopper, and the workability is excellent.In addition, in the polylactic acid composition obtained thereby, the molten liquid crystalline polyester short fiber becomes a single fiber and becomes a poly fiber. By uniformly dispersing in lactic acid, clogging at the gate does not occur, and injection molding can be performed smoothly.
On the other hand, in Comparative Example 1, the melted liquid crystalline polyester was used at the time of kneading and extruding when producing the polylactic acid composition by using the short fibers in which the melted liquid crystalline polyester short fibers were not bonded together in a bundle. Short fibers are frequently clogged with a hopper and cannot be supplied smoothly to a kneader, resulting in inferior workability, and in the polylactic acid composition obtained thereby, the molten liquid crystalline polyester short fibers are in the form of single fibers. Since it is not uniformly dispersed in polylactic acid, clogging occurs at the gate, and injection molding cannot be performed smoothly.

Further, in Examples 1 and 2 using the melt liquid crystalline polyester short fiber bundle in which the short fibers are temporarily bonded to each other by thermal fusion, the molecular weight of polylactic acid in the molded product obtained by injection molding is reduced. Is small.
On the other hand, in Comparative Examples 2 and 3 using a melted liquid crystalline polyester short fiber bundle (c ₁ ) or (c ₂ ) in which short fibers are bonded to each other with an adhesive made of polyurethane resin or polylactic acid resin, The value of the “opening ratio (with stretching treatment)” of the melted liquid crystalline polyester short fiber bundle (c ₁ ) or (c ₂ ) obtained is that the adhered polyurethane resin continues to act as an adhesive even after the stretching treatment. Although it was low (Table 1), when those short fiber bundles (c ₁ ) or (c ₂ ) were added and kneaded into the matrix resin (polylactic acid resin), the adhesive resin (polyurethane resin) was changed to the temperature and the matrix resin. It was peeled off by a high shearing force, and the short fiber bundle was almost completely opened. However, in Comparative Examples 2 and 3, as shown in Table 2, the molecular weight of polylactic acid constituting the molded product obtained by injection molding is greatly reduced as compared with Examples 1 and 2, and the polymer Material degradation has occurred.

<< Examples 3-8 and Comparative Examples 4-5 >>
(1) One of melted liquid crystalline polyester short fiber bundles (a ₁ ), (a ₃ ) to (a ₆ ) and (c ₁ ) obtained in Production Examples ₁ , ₃ to ₆ and 8, and polylactic acid Unite ("TE-4000" manufactured by Unitika Ltd., Mw about 130,000, Mn about 70,000) pellets (columnar pellets having a diameter of about 2 mm x length of 4 mm) are mixed in advance in the amounts shown in Table 3 below. This mixture was continuously fed into an extrusion kneader with a conical hopper as used in Example 1 at a feed rate of 1 kg per hour and kneaded at 190 ° C., then extruded into strands, cut, Pellets of polylactic acid composition containing molten liquid crystalline polyester short fibers were produced.
(2) Use pellets of the polylactic acid composition obtained in (1) above (Examples 3 to 8 and Comparative Example 5), or use polylactic acid pellets not mixed with molten liquid crystalline polyester short fiber bundles (Comparative Example 4) Using the same injection molding machine used in Example 1, under the conditions of the barrel and nozzle temperature of 190 ° C. of the injection molding machine, plate thickness 3.2 mm × length 130 mm × A molded article (test piece) having a width of 12 mm was produced.
(3) Using the test piece (molded product) obtained in (2) above, bending strength, flexural modulus, impact resistance (Izod impact strength with notch) and heat resistance (load deflection temperature: HDT) Was measured by the method described above, and was as shown in Table 3 below.

As can be seen from the results of Table 3 above, in Examples 3 to 8, a melted liquid crystalline polyester short fiber bundle in which short fibers are temporarily bonded to each other by thermal fusion is blended and melt kneaded to produce fibers. Compared to Comparative Example 4 in which a reinforced polylactic acid composition was produced and a molded article (test piece) was produced using the fiber-reinforced polylactic acid composition, the molded article was produced using only polylactic acid. Molded articles having excellent impact and heat resistance have been obtained.
In addition, the molded products obtained in Examples 3 to 8 were molded products of Comparative Example 5 made of a polylactic acid composition manufactured using a molten liquid crystalline polyester short fiber bundle in which short fibers were bonded to each other with a polyurethane resin. Compared to, it is excellent in bending strength and impact resistance.

<< Examples 9 to 15 and Comparative Example 6 >>
(1) Production Examples 1 and 3 to 6 were made into pellets of polylactic acid (“TE-4000” manufactured by Unitika Ltd., Mw about 130,000, Mn about 70,000) (columnar pellets having a diameter of about 2 mm × a length of 4 mm). Table 4 below shows _{one of} the molten liquid crystalline polyester short fiber bundles (a ₁ ) and (a ₃ ) to (a ₆ ) and the inorganic filler (aluminum hydroxide, average particle size 4 μm) obtained in Pre-mixed in the indicated amount, or mixed only with an inorganic filler (the aluminum hydroxide) in the polylactic acid, and this mixture was used in Example 1 as an extrusion kneader with a conical hopper. Is continuously fed at a feed rate of 1 kg per hour, kneaded at 190 ° C., extruded into strands, cut, and pellets of a polylactic acid composition containing molten liquid crystalline polyester short fibers and an inorganic filler or Inorganic filler To prepare pellets of the polylactic acid composition containing only.
(2) Using the polylactic acid composition pellets obtained in (1) above, using the same injection molding machine as used in Example 1, the temperature of the barrel and nozzle of the injection molding machine was 190 ° C. Under the conditions, a molded product (test piece) having a plate thickness of 3.2 mm, a length of 130 mm, and a width of 12 mm was produced.
(3) Using the test piece (molded product) obtained in (2) above, bending strength, flexural modulus, impact resistance (Izod impact strength with notch) and heat resistance (load deflection temperature: HDT) Was measured by the method described above, and was as shown in Table 4 below.

  As seen in the results of Table 4 above, in Examples 9 to 15, a short bundle of liquid crystalline polyester fibers and an inorganic filler (aluminum hydroxide) in which short fibers are temporarily bonded to each other by thermal fusion. Mixing and melt-kneading to produce a fiber reinforced polylactic acid composition, and using the fiber reinforced polylactic acid composition to produce a molded article (test piece), only the inorganic filler (aluminum hydroxide) Compared to Comparative Example 6 in which a molded article was produced using the blended polylactic acid composition, a molded article having excellent impact resistance and heat resistance was obtained.

In the case of the present invention, the molten liquid crystalline polyester short fiber bundle flows smoothly without being agglomerated or clogged in a hopper or other supply path when supplied to a kneading apparatus such as an extruder or a molding apparatus. In addition, the biopolymer composition reinforced with molten liquid crystalline polyester short fibers can be smoothly produced with good workability by being well bitten into the screw of the extruder. Moreover, in the biological polymer composition obtained thereby, the melted liquid crystalline polyester short fibers are monofilamentous and uniformly dispersed, so when performing molding using the biological polymer composition, a nozzle or Since it is possible to smoothly produce various molded articles with good workability without causing clogging at a gate or the like, the fiber-reinforced biopolymer composition obtained in the present invention is an It can be used effectively in the manufacture of various products such as electrical and electronic equipment such as housings, building materials, automobile parts, daily necessities, medical supplies, and agricultural supplies.

Claims (6)

  A method for producing a fiber-reinforced biological polymer composition by blending a short fiber bundle made of molten liquid crystalline polyester fiber into a biological polymer and kneading under heating, wherein the short fiber bundle made of molten liquid crystalline polyester fiber As a short, the melted liquid crystalline polyester short fibers constituting the short fiber bundle are temporarily bonded to each other by heat fusion with an adhesive strength that separates into individual single fibers by heat and / or shear force during kneading. A method for producing a fiber-reinforced biological polymer composition, comprising using a fiber bundle.   The method for producing a fiber-reinforced biopolymer composition according to claim 1, wherein the fiber length of the short fiber bundle made of molten liquid crystalline polyester fiber is 0.5 to 20 mm.   A short bundle of molten liquid crystalline polyester fibers is a molten liquid crystalline polyester long fiber bundle having a tensile strength of 15 cN / dtex or more and a tensile initial elastic modulus of 400 cN / dtex or more obtained by temporarily heat-bonding single fibers to each other on the fiber surface. The method for producing a fiber-reinforced biopolymer composition according to claim 1 or 2, wherein the fiber is a short fiber bundle cut into short fibers.   The fiber-reinforced biopolymer according to any one of claims 1 to 3, wherein a molten liquid crystalline polyester short fiber bundle is blended at a ratio of 0.5 to 50 parts by mass with respect to 100 parts by mass of the biopolymer. A method for producing the composition.   It is obtained by the production method according to any one of claims 1 to 4, wherein short fibers made of molten liquid crystalline polyester are dispersed in a biological polymer in the form of single fibers. Fiber reinforced biological polymer composition. A molded article produced from the fiber-reinforced biopolymer composition according to claim 5.