JPH0987530A - Thermoplastic resin composition, method for injection-molding the same and injection molding of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-rigidity and high-strength molding by injection- molding a thermoplastic resin composition (C) comprising a thermoplastic resin (A) and a liquid crystal polymer (B) under specified melt viscosity conditions. SOLUTION: Components A and B are selected so that the melt flow rate of component A may be 0.15-100 and the flow initiation temperature of component B is 80-210 deg.C under conditions of the processing temperature of composition C comprising 99-50wt.% component A (e.g. polyolefin-type polymer) and 1-50 (the total of both is 100wt.%) component B (e.g. aromatic hydroxycarboxylic acid/ethylene glycol/terephthalic acid copolymer). Composition C is injection- molded under conditions including a processing temperature equal to or higher than the melt flow initiation temperature of component B and a velocity at which the molten resin passes the gate of 500m/min or above. An injection mold having an SR/SG ratio of 3-150 (wherein SG is the sectional area of the gate, and SR is the sectional area of the runner) is used. Component B has been dispersed in the matrix phase comprising component A in the form of particles of an average aspect ratio of 6 or above.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition comprising a thermoplastic resin (A) which does not form an anisotropic melt phase and a liquid crystalline polymer (B) which can form an anisotropic melt phase, and its injection. The present invention relates to a molding method and an injection molded body.

[0002]

2. Description of the Related Art Liquid crystalline polymers capable of forming an anisotropic molten phase have high strength, high rigidity,
Although it is a thermoplastic resin having many properties such as high heat resistance and easy moldability, it has a commercial disadvantage such as higher price because it has different molding shrinkage and mechanical properties in the direction perpendicular to the molecular chain orientation direction. On the other hand, thermoplastic resins using one or more of polyolefin-based (co) polymers, styrene-based (co) polymers, polyamide-based (co) polymers, polyacrylates and polyacetal (co) polymers are relatively It is inexpensive and has excellent slidability or impact characteristics, but it has the disadvantage of poor physical properties such as heat resistance and rigidity. Especially when used for thin-walled housings, the fluidity of the molten resin at the time of manufacture and the rigidity of the molded product are insufficient, so it is unavoidable to make it thick in design, so in the field of electric, electronic, communication equipment these days. There was a limit to the reduction in size and weight. Therefore, attempts have been made to utilize the advantages of the liquid crystalline polymer and the thermoplastic resin and to mix and use them in order to compensate for the drawbacks of both. JP-A-5-70700 and JP-A-5-700
As described in Japanese Patent No. 112709, first, the liquid crystalline polymer is extruded while stretching at a temperature at which both the liquid crystalline polymer and the thermoplastic resin are melted, so that the liquid crystalline polymer has a predetermined aspect ratio (length / thickness). When the molding material is prepared so that it exists in the form of large fibers, and the molding material is molded, the molding material is molded at a temperature at which only the thermoplastic resin is melted without melting the liquid crystalline polymer. A method for producing a molded article containing a fibrous liquid crystalline polymer having a reinforcing effect has been considered. However, in these methods, extruding while stretching in advance, further stretching the melt extrudate with a roller or the like to form a composition in which the liquid crystalline polymer is oriented in a fibrous state, and then molding by injection molding or the like. When a body is obtained, the body is molded at a molding temperature below the melting point of the liquid crystalline polymer. Alternatively, when a molded product is prepared from the beginning, a considerably large shearing force must be applied when the mold is filled with the resin composition to align the liquid crystalline polymer. Therefore, in the former case, the fluidity is deteriorated, the molding conditions are narrowed, and the rigidity is not sufficiently satisfactory. In the latter case, the shape of the molded product is considerably affected, and the strength is insufficient because the orientation is not sufficient depending on the place. Further, the melting point of the liquid crystalline polymer blended with the thermoplastic resin is too high, and the thermoplastic resin may be decomposed during processing, so that the inherent advantages of the thermoplastic resin have not been utilized.

[0003]

In view of the above problems, the inventors of the present invention have eagerly searched and studied for a material having excellent properties as a thin molding material, and found that the thermoplastic resin (A) and the liquid crystalline polymer By using (B) to specify the melt viscosity condition during the injection molding and using a liquid crystalline polymer having a relatively low flow initiation temperature in consideration of the melting point of the thermoplastic resin, the liquid crystalline polymer can be easily formed into a fiber. It has been found that a thin-walled molded product that exhibits a very high reinforcing effect that has not existed in the past, and therefore has a unique property of the molded product, can be a thin-walled molded product that is particularly excellent in mechanical strength. .

That is, according to the present invention, one or more of polyolefin (co) polymers, styrene (co) polymers, polyamide (co) polymers, polyacrylates and polyacetal (co) polymers are used. 99 to 50 wt% of the thermoplastic resin (A) and 1 to 5 of the liquid crystalline polymer (B)
A thermoplastic resin composition comprising 0% by weight (total of 100% by weight of both), wherein the thermoplastic resin (A) has a melt flow value of 0.15 to 0.15 under processing temperature conditions of the thermoplastic resin composition. A thermoplastic resin composition is provided, wherein the liquid crystalline polymer (B) has a flow starting temperature of 80 to 210 ° C. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the melting point or softening point of the thermoplastic resin (A) is 210 ° C. or lower. Further, according to the present invention, when the thermoplastic resin composition is subjected to heat treatment under a temperature condition equal to or higher than the melting point of the liquid crystalline polymer (B) without any load, the liquid crystalline polymer (B) has a weight average particle size. The diameter is in the range of 10 to 40 μm, and 80% by weight or more of the diameter is 0.5 to 60 μm.
The thermoplastic resin composition is characterized by being island-like micro-dispersed in the matrix phase of the thermoplastic resin (A) so as to fall within the range. Further, according to the present invention, the viscosity ratio (A η / A) of the thermoplastic resin (A) and the liquid crystalline polymer (B) when the shear rate is 1200 sec ⁻¹ at the processing temperature equal to or higher than the flow starting temperature of the liquid crystalline polymer (B). Bη)
Is 0.1 or more. The above-mentioned thermoplastic resin composition is provided. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the thermoplastic resin (A) is a polyacetal resin. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the thermoplastic resin (A) is a polyolefin (co) polymer. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the thermoplastic resin (A) is a styrene (co) polymer. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the thermoplastic resin (A) is a polyamide (co) polymer. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the liquid crystalline polymer (B) comprises a constitutional unit of aromatic hydroxycarboxylic acid / aliphatic diol / aromatic dicarboxylic acid. . Further, according to the present invention, the liquid crystalline polymer (B) is composed of constitutional units of aromatic hydroxycarboxylic acid / ethylene glycol / terephthalic acid, and the content of aromatic hydroxycarboxylic acid is 30 to 70 mol%. The above-mentioned thermoplastic resin composition is provided. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the aromatic hydroxycarboxylic acid is p-hydroxybenzoic acid. Further, according to the present invention, there is provided the thermoplastic resin composition, wherein the aromatic hydroxycarboxylic acid comprises p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. Further, according to the present invention, the thermoplastic resin composition is used as a liquid crystalline polymer (B).
An injection molding method of a thermoplastic resin composition is provided, which is characterized in that injection molding is performed under a condition that a molten resin passes through a gate at a processing temperature of not less than 500 m / min at a processing temperature equal to or higher than the flow starting temperature. Further, according to the present invention, the ratio S _R / S _G of the cross-sectional area S _R of the runner to the cross-sectional area S _G of the gate is 3
The injection molding method of the thermoplastic resin composition is characterized by using a mold for injection molding in the range of 150 to 150. Further, according to the present invention, there is provided an injection-molded article comprising the thermoplastic resin composition, wherein the liquid crystalline polymer is fibrous having an average aspect ratio of 6 or more and dispersed in the matrix phase of the thermoplastic resin (A), and The liquid crystalline polymer (B) is obtained by cooling the injection-molded article through a heat treatment under a temperature condition of the melting point of the liquid crystalline polymer (B) or higher without any load.
Is in the range of 10 to 40 μm in weight average particle size, and 80% by weight or more thereof is in the range of 0.5 to 60 μm in particle size. An injection-molded article is provided.

The thermoplastic resin (A) to which the present invention is applied is, for example, polyethylene, polypropylene or poly-4.
-Polyolefin (co) polymer such as methyl-1-pentene, ABS resin, styrene (co) polymer such as AES, AS, PS, polyamide (co) polymer, polyacrylate, polyacetal (co) polymer Examples thereof include a combination and a resin mainly containing these resins, and one kind or a mixture of two or more kinds may be used. The reason why these thermoplastic resins are preferable is that, for example, a polyolefin-based (co) polymer is very inexpensive and well balanced in physical properties, and a styrene-based (co) polymer has a small molding shrinkage ratio.
In addition, polyamide-based (co) polymers have relatively good heat resistance, and polyacetal-based (co) polymers have good sliding properties. Usually, such (co) polymers have a melting point. Alternatively, the softening point is 210 ° C. or lower. Further, these thermoplastic resins (A) will be described in detail.

The polyacetal resin in the present invention means
A polymer compound having an oxymethylene unit — (OCH ₂ ) — as a main constituent unit, a polyoxymethylene homopolymer, or an oxymethylene group as a main repeating unit,
In addition to this, other structural units such as ethylene oxide,
A copolymer containing a small amount of comonomer units such as 1,3-dioxolane, 1,4-butanediol and formal,
It may be either a terpolymer or a block polymer, and the molecule may have not only a linear structure but also a branched or crosslinked structure. Further, a known modified polyoxymethylene having another organic group introduced may be used. The degree of polymerization is not particularly limited, and those having moldability, for example, a melt flow (MFR) value under load of 190 ° C. and 2160 g of 0.15 to 100 g / 10 minutes, preferably 0.5 to It may be 50 g / 10 minutes.

The polyolefin (co) polymer in the present invention is a homopolymer of α-olefin such as ethylene, propylene, butene, hexene, octene, nonene, decene and dodecene, or a random mixture of two or more kinds thereof. , Block or graft copolymers, or non-conjugated dienes such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene and 2,5-norbonadiene, and conjugated dienes such as butadiene, isoprene and piperylene. Component, derivatives of α, β-unsaturated acids such as acrylic acid and methacrylic acid or their esters, aromatic vinyl compounds such as acrylonitrile, styrene, α-methylstyrene, vinyl esters such as vinyl acetate, vinyl methyl ether, etc. Vinyl ethers and their vinylization Random, block, or graft copolymers containing one or more of the comonomer components such as product derivatives, etc., such as the degree of polymerization, presence or absence of side chains or branches, degree, copolymer composition ratio, etc. It doesn't matter.

The styrene-based (co) polymer in the present invention is mainly styrene and is obtained by a radical polymerization reaction or an ionic polymerization reaction. Industrially, the bulk polymerization, solution polymerization, suspension polymerization, Any of those obtained by emulsion polymerization or the like can be used. Further, styrene may be the main component and other reactive monomers such as vinyl compounds and diene compounds may be copolymerized or a rubber component may be introduced so long as the properties are not significantly impaired. In particular, polystyrene, poly α-methylstyrene or mainly these, acrylic acid, methacrylic acid, or their esters, acrylonitrile, butadiene,
A copolymer with ethylene chloride or the like is also preferably used, regardless of the degree of polymerization, the presence or absence of side chains or branches, the degree thereof, the composition ratio of the copolymer and the like. Specifically, PS, HIPS, AS, A
Examples include ES, ABS, MBS and the like.

The polyamide (co) polymer in the present invention is a polyamide obtained from ω-amino acid or ω-lactam, or a diamine or m-xylenediamine and adipic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acid, A homopolymer or copolymer obtained from a dicarboxylic acid such as terephthalic acid or isophthalic acid, and further a mixed polymer or the like. Preferred polyamides include homopolyamides such as nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, adipic acid / terephthalic acid / hexamethylenediamine, adipic acid / 1,4-cyclohexanedicarboxylic acid / hexamethylenediamine, Copolyamides such as adipic acid / 1,3-cyclohexanedicarboxylic acid / hexamethylenediamine, terephthalic acid / isophthalic acid / hexamethylenediamine / paraaminocyclohexylmethane and the like can be mentioned.

To the thermoplastic resin, additives such as a nucleating agent, a pigment such as carbon black, an antioxidant, a stabilizer, a plasticizer, a lubricant, a release agent and a flame retardant are added to obtain desired characteristics. A thermoplastic resin provided with is also included in the range of the thermoplastic resin of the present invention.

The liquid crystalline polymer (B) in the present invention refers to a melt processable polymer having a property of forming an optically anisotropic melt phase having a flow initiation temperature of 80 to 210 ° C. The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarizing microscope and observing the molten sample placed on the Leitz hot stage at a magnification of 40 times under a nitrogen atmosphere. When the liquid crystalline polymer applicable to the present invention is inspected between orthogonal polarizers, polarized light is normally transmitted even when it is in a molten stationary state, and exhibits optical anisotropy.

Examples of the above-mentioned liquid crystalline polymer (B) include aromatic polyester or aromatic polyesteramide, aromatic polyester or polyester partially containing the aromatic polyesteramide in the same molecular chain.

Liquid crystalline polymer (B) applicable to the present invention
The aromatic polyester or the aromatic polyester amide has as a constituent component at least one compound selected from the group consisting of aromatic hydroxycarboxylic acid, aromatic aminocarboxylic acid, aromatic hydroxyamine, and aromatic diamine. Aromatic polyesters and aromatic polyester amides. More specifically, (1) 1 mainly of aromatic hydroxycarboxylic acid and its derivative
One or two or more of (a) an aromatic hydroxycarboxylic acid and its derivative and (b) an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and its derivative Polyester comprising one or more kinds and (c) at least one kind or two or more kinds of aromatic diol, alicyclic diol, aliphatic diol and derivatives thereof; (3) mainly (a) aromatic hydroxy One or more carboxylic acids and their derivatives, (b) one or more aromatic hydroxyamines, aromatic diamines and their derivatives, and (c) aromatic dicarboxylic acids and alicyclic dicarboxylic acids. And one or more kinds of derivatives thereof, and (4) mainly (a) an aromatic hydroxycarboxylic acid,
One or more aromatic aminocarboxylic acids and their derivatives, (b) one or more aromatic hydroxyamines, aromatic diamines and their derivatives, and (c) aromatic dicarboxylic acids, alicyclics Examples include polyester amides comprising one or more kinds of group dicarboxylic acids and their derivatives, and (d) at least one kind or two or more kinds of aromatic diols, alicyclic diols, aliphatic diols and their derivatives. To be Further, if necessary, a molecular weight modifier may be used in combination with the above constituent components. When these are dissolved in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C., 0.5 or more, preferably 2.0 to 10.0 dl / g
Those having a logarithmic viscosity (IV) of 1 are used and may include an oligomer region.

Specific examples of the compound constituting the liquid crystal polymer (B) applicable to the present invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, and aminobenzoic acid. Aromatic aminocarboxylic acids such as acids, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, the following general formula [1] and the following general formula [2] Aromatic diols such as compounds to be treated; ethylene glycol, 1,4-
Aliphatic glycols typified by butanediol; terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and aromatic dicarboxylic acids such as compounds represented by the following general formula [3] acid;
Examples thereof include aromatic amines such as p-aminophenol and p-phenylenediamine.

[0015]

Embedded image

A particularly preferred liquid crystal polymer (B) to which the present invention is applied is an aromatic polyester having an aromatic hydroxycarboxylic acid and ethylene glycol or terephthalic acid as a constitutional unit from the viewpoint of a flow initiation temperature of 80 to 210 ° C. is there. In this case, the content of the aromatic hydroxycarboxylic acid is 30 to 70 mol%, preferably 35 to 55 mol%, and particularly preferably 40 to 45 mol%. Furthermore, the aromatic hydroxycarboxylic acid is preferably p-hydroxybenzoic acid, or a mixed constitution of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.
In the latter case, in particular, p-hydroxybenzoic acid and 6-
The ratio of hydroxy-2-naphthoic acid is 50:50 to 7
0:30 is preferable, and the ratio is particularly 55: 45-6.
5:35 is preferred. Liquid crystalline polymer (B) of the present invention
The degree of polymerization of the substance obtained by any of the above compositions may include an oligomer region.

The thermoplastic resin composition of the present invention comprises the thermoplastic resin (A) and the liquid crystalline polymer (B). Thermoplastic resin (A) and liquid crystalline polymer (B)
The composition ratio of the former is 99 to 50% by weight, preferably 95 to 60% by weight, and the latter is 1 to 50% by weight, preferably 5 to 40% by weight (the total of both is 100% by weight). The composition ratio of the liquid crystalline polymer (B) is 1 to 50% by weight.
Within the range, the matrix phase will not be inverted, and the thermoplastic resin (A) can be reinforced with the liquid crystalline polymer (B). Further, when the composition is heat-treated under a temperature condition not lower than the melting point of the liquid crystalline polymer and cooled to room temperature without any load, and the obtained composition is observed, the liquid crystalline polymer (B) is a thermoplastic resin ( It is necessary that the matrix phase of A) is microdispersed in an island shape. The dispersion state of the liquid crystalline polymer (B) is in the range of 10 to 40 μm in weight average particle diameter, particularly preferably in the range of 15 to 30 μm, and the liquid crystalline polymer (B) is
80% by weight or more is in the range of 0.5 to 60 μm, preferably 5 to 50 μm. The heat treatment is a means for making the liquid crystalline polymer (B) into a spherical shape that is easy to observe even if the liquid crystalline polymer (B) is dispersed in a shape other than a spherical shape, and the heat treatment temperature is equal to or higher than the melting point of the liquid crystalline polymer (B). However, in order to completely melt and spheroidize the liquid crystalline polymer, it is preferable to leave it at a temperature higher than the melting point by 10 ° C. or more and for 20 seconds or more, particularly 30 seconds to 3 minutes. When the dispersion having a shape other than the spherical shape remains, the heat treatment time may be extended, but when the heat treatment time becomes longer, it may be melted depending on the combination of the thermoplastic resin (A) and the liquid crystalline polymer (B). Since the spherical liquid crystalline polymer (B) may agglomerate and change its microdispersion state, it is preferable to use a particle size converted into a spherical shape without extending the heat treatment time.

To produce a thermoplastic resin composition in which the liquid crystalline polymer (B) is micro-dispersed in an island shape in the matrix phase of the thermoplastic resin (A) when cooled through the above heat treatment, Both may be blended in the above composition ratio and kneaded. Usually, the mixture is kneaded by an extruder, extruded into pellets and used for the next injection molding, but the kneading by such an extruder is not limited. As the kneading method,
A single-screw or twin-screw extruder used for kneading and extruding a usual thermoplastic resin is used. In order to obtain the above-mentioned dispersed thermoplastic resin composition, (1) flow of the liquid crystalline polymer (B) is used. Processing temperature above the starting temperature, shear rate 1200 sec ^-1
The melt viscosity ratio (Aη / Bη) of the thermoplastic resin (A) and the liquid crystalline polymer (B) measured by
Preferably, there are a method of 0.1 to 6 or less, (2) a method of repeating kneading and extrusion, (3) a method of finely granulating the liquid crystalline polymer (B) to be blended, etc. Two types of methods can be used together. Among these, the method (1) of setting the melt viscosity ratio to a specific range is preferable from the viewpoint of easily obtaining the above-mentioned microdispersed thermoplastic resin composition. If the melt viscosity is 0.1 or less, the viscosity of the matrix (thermoplastic resin) phase is too low,
The liquid crystalline polymer (B) is not subjected to sufficient shear stress and extension stress, and the liquid crystalline polymer is difficult to be fibrous. Viscosity ratio is 6
When it exceeds, the liquid crystalline polymer (B) is fibrillated,
Since the viscosity of the thermoplastic resin (A) becomes high, the fiber diameter of the fibrous liquid crystalline polymer becomes large and the efficiency of the reinforcing action becomes poor, and problems such as poor fluidity at the time of molding may occur. Absent. The liquid crystalline polymer (B)
The flow initiation temperature of is a temperature at which the liquid crystalline polymer (B) exhibits fluidity due to an external force when the temperature of the liquid crystalline polymer (B) is increased by heating, and is measured by the method described below.

In order to produce the thermoplastic resin composition as described above, both may be blended in the above composition ratio and kneaded.
Usually, the mixture is kneaded by an extruder, extruded into pellets, and used for injection molding or the like, but the kneading by such an extruder is not limited.

In the thermoplastic resin composition according to the present invention, it is necessary that the liquid crystalline polymer (B) is micro-dispersed to the extent as described above when it is cooled through heat treatment. The liquid crystalline polymer (B) may be fiberized in the composition as disclosed in JP-A-5-112709 and JP-A-5-70700, but such fiberization is possible. Is not necessary.
Therefore, it is not necessary to form oriented fibers by stretching the roll, which is performed at the time of melting after the extruder as described in the above publication. In the present invention, the thermoplastic resin composition in which the liquid crystalline polymer (B) is in the above-mentioned dispersed state is injection-molded under the conditions described below, so that the particles of each microdispersed liquid crystalline polymer (B) can be easily Since fibers are formed in a state where the ratio is large, fibers are uniformly formed inside the injection-molded body, and the strength is easily higher than that of the molded body obtained by a known method with the composition ratio of the same liquid crystalline polymer (B). High rigidity will be exhibited.

Next, the injection molding method of the present invention will be described. In the present invention, it is preferable to use the thermoplastic resin composition in which the liquid crystalline polymer (B) as described above is micro-dispersed in the matrix phase of the thermoplastic resin (A) and to use the injection molding conditions described below. This is a feature of the injection molding method. The first of the injection molding conditions is to set the temperature (processing temperature) of the thermoplastic resin composition at the time of injection to be the flow initiation temperature of the liquid crystalline polymer (B) or higher, preferably 10 ° C. higher than the flow initiation temperature. is there. Due to this temperature condition, when the thermoplastic resin composition in a fluidized state passes through the gate leading to the mold cavity of the injection molding machine at the time of injection molding, the liquid crystalline polymer (B) micro-dispersed in an island shape is heated. It is stretched in the matrix phase of the plastic resin (A) and sufficiently fiberized. That is, this fiberization makes it possible to obtain an injection-molded article having a sufficiently high function in the dispersed state and having high rigidity and high strength. When the liquid crystalline polymer (B) dispersed in an island shape is not micro-dispersed, the number of the liquid crystalline polymer (B) formed into fibers becomes small and an injection molded article having high rigidity and high strength can be obtained. In some cases, it is an important requirement that the liquid crystalline polymer (B) be micro-dispersed in an island shape. From the viewpoint of saving energy and preventing thermal decomposition of the thermoplastic resin composition, the upper limit of the resin temperature is preferably not higher than the thermal decomposition temperature of the liquid crystalline polymer (B), particularly preferably the melting point of the liquid crystalline polymer (B) plus 50 ° C. Keep below. The processing temperature in the present invention is a set temperature of a resin processing machine such as a molding machine. However, even if the set temperature is equal to or lower than the liquid crystal start temperature, the present invention includes as long as the resin temperature is equal to or higher than the liquid crystal start temperature.

The second injection molding condition is the speed of the molten thermoplastic resin composition passing through the gate. The passing speed of this gate is 500 m / min or more, preferably 1,000
m / min or more, more preferably 3,000 m / min or more. By satisfying this condition and performing injection molding, in combination with the temperature condition, the fiberization of the liquid crystalline polymer (B) by the stretching during the passage can be sufficiently achieved.
The higher the passage speed of the gate is, the more preferable. However, the upper limit is preferably 100,000 m / min or less in view of the performance of an ordinary molding machine.
It is also possible to use 50,000 m / min or more.

As a mold used for the injection molding, the ratio S _R / S _G of the cross-sectional area S _R of the runner to the cross-sectional area S _G of the gate is in the range of 3 to 150, particularly 6 to 120. That promotes fiberization of the liquid crystalline polymer (B),
It is particularly preferable because the aspect ratio of the fibers generated in the matrix phase can be increased. The gate and runner cross-sectional areas are defined as shown in FIG. 1 depending on the type of gate. A gate having a shape not shown in the figure can be similarly defined. In the case of the side gate and film gate of FIG. 1A and the overlap gate of FIG. 1B, S _G = S _Y when S _X > S _Y and S _X <S _Y
, S _G = S _X , and S _X = S _Y , S _G = S _X =
It is S _Y. In the case of the pin gate of FIG. 1C, S _R = S _X when the cross-sectional area S _X > S _Y and S when S _X <S _{Y.
When R} = S _Y and S _X = S _Y , S _R = S _X = S _Y. In the case of the direct gate shown in FIG. 1D, the area of the conical bottom surface of the conical runner is S _R, and the area of the virtual outer peripheral surface of the cylinder formed immediately below the conical bottom surface is S _G. Further, in the case of the disc gate of FIG. 1E, the area of the conical bottom surface in the figure is S _R , and similarly to the case of the direct gate, the area of the outer peripheral surface of the virtual cylinder formed in the gate in the figure is S S.
_{Let G.}

The resin pressure at the time of injection molding is appropriately set so as to satisfy the velocity condition of the molten thermoplastic resin composition passing through the gate, but it is usually 300 to 2,000 Kg / c.
m ² , preferably in the range of 500 to 1,500 Kg / cm ² .

In the injection-molded article obtained by the above-mentioned injection molding method, the liquid crystalline polymer (B) is dispersed in the matrix phase of the thermoplastic resin (A) in a fibrous form having an average aspect ratio of 6 or more, preferably 8 or more. . Further, the fibrous liquid crystalline polymer (B) is relaxed by heating the molded product dispersed in the fibrous state under no load under a temperature condition of the melting point of the liquid crystalline polymer (B) or higher, and cooled to room temperature. When the liquid crystalline polymer (B) has a weight average particle size of 10 to 40 μm and 80% by weight or more thereof has a particle size of 0.5 to 60 μm.
A major feature is that the thermoplastic resin (A) is micro-dispersed in the matrix phase of the thermoplastic resin (A) so as to be in the range of m. The heat treatment temperature and the holding time in this case are the same as in the case of the thermoplastic resin composition of the present invention. Liquid crystalline polymer (B) observed when the above-described thermoplastic resin composition according to the present invention is cooled without heat treatment under a temperature condition higher than the melting point of the liquid crystalline polymer (B). Since the dispersion state itself does not substantially change even when it is re-kneaded and passed through the gate under the injection molding conditions, the injection molded article is heated as described above to change the dispersion state of the liquid crystalline polymer (B). By observing, it can be easily discriminated that it is an injection-molded article according to the present invention and whether or not the above-mentioned thermoplastic resin composition is used as a raw material thereof.

As described above, the molded product obtained by using the thermoplastic resin composition of the present invention contains the liquid crystalline polymer (B) contained in a fibrous form and has a reinforcing action. For this reason, a filler usually blended is not necessary, but depending on the application, to the extent that the effect of the present invention is not impaired,
Known fibrous, powdery, plate-like or hollow fillers may be blended.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. The method for evaluating the injection-molded article is as follows.

(Melt flow value) ASTM D1238
According to -89E, the melt flow value at the processing temperature (g / 1
0 minutes) was measured.

(Flowing start temperature) Capillary rheometer (Flow tester CFT-500 manufactured by Shimadzu Corporation)
Mold), and the sample resin heated and melted at a temperature rising rate of 4 ° C./min under a load of 100 Kg / cm ² and an inner diameter of 1
The melt viscosity was expressed at a temperature of 48,000 poise when extruded from a nozzle having a length of 10 mm and a length of 10 mm.

(Flexural Modulus) According to ASTM D790, the flexural modulus (Kg / cm ² ) of a bending test piece having a thickness of 1/32 inch was measured.

(Average Aspect Ratio of Fibrous Liquid Crystalline Polymer) The test piece used for the measurement of flexural modulus was cut so that a plane parallel to the flow direction would appear, and the cross section was mirror-polished. It was observed and evaluated by. The thickness and length of 50 arbitrarily selected fibrous liquid crystalline polymers were measured. Regarding the length, the length of the portion that can be observed on the surface was defined as the length of the fiber. The results are shown by ◯ when the average aspect ratio is 8 or more, Δ when the average aspect ratio is 8 to 6, and x when the average aspect ratio is less than 6.

(Dispersion Particle Diameter of Liquid Crystalline Polymer (B)) A pellet after melt-kneading or a part of a test piece after molding is heated in a nitrogen stream to a temperature 10 ° C. higher than the melting point of the liquid crystalline polymer for 3 minutes. It was kept at that temperature and then cooled to room temperature. The cut surface of the sample after heat treatment and cooling was observed by an electron microscope and evaluated. The diameter of 50 particles of the liquid crystalline polymer arbitrarily selected was measured, and the weight average particle diameter was obtained.

(Melt viscosity) Pellets or powders of each resin were measured with a Toyo Seiki Capillograph for 1200 sec.
The melt viscosity under shear stress of c ^-1 was measured at the processing temperature of each thermoplastic resin composition.

(Vicat softening point) Measured according to JIS K6870.

Example 1 Polyacetal resin (manufactured by Polyplastics Co., Ltd., M25-44 (MI = 2.
5), the melting point of 165 ° C.) and the liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7:
The resin No. 3 was blended, melt-kneaded at a resin temperature of 190 ° C. with a 30 mm twin-screw extruder, and pelletized. Next, the pellets are molded at a molding temperature of 19 with an injection molding machine (side gate).
The test piece was molded at 0 ° C., and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester of the pellets before being melted without load is 25 (μm) on a weight average, and 80% by weight or more of the dispersed particles have a particle diameter of 5 to 45 (μm). Was in range. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

(Example 2) Polyacetal resin (manufactured by Polyplastics Co., Ltd., M90-44 (MI = 9.
0), melting point 165 ° C.) and the liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7:
The resin No. 3 was blended, melt-kneaded at a resin temperature of 190 ° C. with a 30 mm twin-screw extruder, and pelletized. Next, the pellets are molded at a molding temperature of 19 with an injection molding machine (side gate).
The test piece was molded at 0 ° C., and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 30 (μm) on a weight average, and 80% by weight or more of the dispersed particles have a particle diameter of 5 to 45 (μm). Was in range. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Example 3 Polyacetal resin (manufactured by Polyplastics Co., Ltd., M90-44 (MI = 9.
0), melting point 165 ° C.) and the liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7:
The resin No. 3 was blended, melt-kneaded at a resin temperature of 190 ° C. with a 30 mm twin-screw extruder, and pelletized. Then, the pellets are molded at a molding temperature of 190 with an injection molding machine (pin gate).
The test piece was molded at ℃, and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. Table-Results
It is shown in FIG. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 30 (μm) on a weight average, and 80% by weight or more of the dispersed particles have a particle diameter of 5 to 45 (μm). Was in range. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 25 (2) Gate passing speed: 2850 (m / min) (3) Injection pressure: 1200 (Kg / cm ² ) (4) Injection speed: 5. 8 (m / min)

(Example 4) Polyacetal resin (manufactured by Polyplastics Co., Ltd., M270-44 (MI = 27.
0), melting point 165 ° C.) and the liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7:
The resin No. 3 was blended, melt-kneaded at a resin temperature of 190 ° C. with a 30 mm twin-screw extruder, and pelletized. Next, the pellets are molded at a molding temperature of 19 with an injection molding machine (side gate).
The test piece was molded at 0 ° C., and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 30 (μm) on a weight average, and 80% by weight or more of the dispersed particles have a particle diameter of 5 to 45 (μm). Was in range. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Comparative Example 1 Polyacetal resin (manufactured by Polyplastics Co., Ltd., M90-44 (MI = 9.
0), melting point 165 ° C.) and liquid crystalline polyester (Polyplastics Co., Ltd., Vectra A950) powder in a mixing ratio of 7: 3, and a resin temperature of 190 ° C. in a 30 mm twin-screw extruder. Was melt-kneaded and pelletized.
Then, the pellets were molded into a test piece at a molding temperature of 190 ° C. with an injection molding machine (side gate), and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. The dispersed particle size of the liquid crystalline polyester of the pellets before molding (observed without heat treatment) was complex and inconstant and could not be evaluated. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Example 5 Polypropylene resin (manufactured by Mitsui Petrochemical Co., Ltd., Hypol J600 (MI = 7.
0), a melting point of 160 ° C.) and a liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7:
The resin of No. 3 was blended, melt-kneaded at a resin temperature of 230 ° C. by a 30 mm twin-screw extruder, and pelletized. Next, the pellets are molded at a molding temperature of 23 with an injection molding machine (side gate).
The test piece was molded at 0 ° C., and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester of the pellets before being melted without load is 25 (μm) on a weight average, and 80% by weight or more of the dispersed particles have a particle diameter of 5 to 45 (μm). Was in range. The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Example 6 Polypropylene resin (manufactured by Mitsui Petrochemical Co., Ltd., Hipol J900 (MI = 4)
0.0), melting point 160 ° C.) and liquid crystalline polyester (Rod Run LC3000 manufactured by Unitika Ltd.) in a mixing ratio of 7: 3, and the mixture was mixed with a 30 mm twin-screw extruder at a resin temperature of 230 ° C. Melt kneaded and pelletized. Then
Test pieces were molded from the pellets at a molding temperature of 230 ° C. using an injection molding machine (side gate), and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 30 (μm) on a weight average, and 80% by weight of the dispersed particles.
The above is in the range of the particle size of 5 to 45 (μm). The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Example 7 Polystyrene resin (manufactured by Mitsui Toatsu Chemicals, Inc., Topolex 500 (MI = 4.
0), a Vicat softening point of 86 ° C.) and a liquid crystalline polyester (manufactured by Unitika Ltd., Rod Run LC3000) in a mixing ratio of 7: 3, and blended in a 30 mm twin screw extruder at a resin temperature of 190 ° C. Melt kneaded and pelletized. Then, the pellets were molded into a test piece at a molding temperature of 190 ° C. with an injection molding machine (side gate), and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 25 (μm) on a weight average, and the dispersed particle diameter is 8
0% by weight or more was in the range of particle diameter 5 to 45 (μm).
The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

Example 8 Polyamide resin (UBE Nylon 6 (1013B) manufactured by Ube Industries, Ltd., melting point 21)
(0 ° C) and a liquid crystalline polyester (Rodrun LC3000 manufactured by Unitika Ltd.) were mixed in a resin ratio of 7: 3, and melt-kneaded at a resin temperature of 230 ° C with a 30 mm twin-screw extruder to form pellets. did. Then, the pellets were molded into a test piece at a molding temperature of 230 ° C. by an injection molding machine (side gate), and the mechanical properties, melt viscosity, and average aspect ratio of the liquid crystalline polyester were evaluated. The results are shown in Table 1. In addition, the dispersed particle diameter of the liquid crystalline polyester obtained by melting the pellets before molding with no load is 30 (μm) on a weight average.
80% by weight or more of the dispersed particles have a particle diameter of 5 to 45.
It was in the range of (μm). The molding conditions are as follows. (1) Runner cross-sectional area S _R / gate cross-sectional area S _G : 9.3 (2) Gate passing speed: 1200 (m / min) (3) Injection pressure: 800 (Kg / cm ² ) (4) Injection speed: 5.8 (m / min)

[0044]

[Table 1]

[0045]

As described above in detail, by using the thermoplastic resin composition according to the present invention and performing injection molding under the molding conditions according to the present invention, a dispersion which has hitherto been obtained by the same kind of technique cannot be obtained. It has become possible to obtain a thermoplastic resin molded product containing the fibrous liquid crystalline polymer.
Since this molded product has the characteristics of extremely high rigidity and high strength, it is particularly preferably applied to a thin-walled molded product.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a cross-sectional area of a gate and a runner.

[Table-1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08L 33/08 LJE C08L 33/08 LJE 59/00 LMP 59/00 LMP 67/00 LNZ 67/00 LNZ 77/00 LQU 77/00 LQU 77/10 77/10 77/12 LQR 77/12 LQR

Claims (15)

[Claims] 1. A thermoplastic resin containing one or more of a polyolefin-based (co) polymer, a styrene-based (co) polymer, a polyamide-based (co) polymer, a polyacrylate, and a polyacetal (co) polymer ( A) 99 to 50% by weight and liquid crystalline polymer (B) 1 to 50% by weight (both total 10
0% by weight), wherein the thermoplastic resin (A) has a melt flow value of 0.15 to 100 under processing temperature conditions of the thermoplastic resin composition.
And the flow starting temperature of the liquid crystalline polymer (B) is 80 to
It is 210 degreeC, The thermoplastic resin composition characterized by the above-mentioned. 2. The thermoplastic resin composition according to claim 1, wherein the melting point or softening point of the thermoplastic resin (A) is 210 ° C. or lower. 3. The liquid crystal polymer (B) has a weight-average particle size when the thermoplastic resin composition is cooled under heat treatment under a temperature condition of the melting point of the liquid crystal polymer (B) or more under no load. It is characterized in that it is micro-dispersed in an island shape in the matrix phase of the thermoplastic resin (A) so that it is in the range of 10 to 40 μm and 80% by weight or more thereof is in the range of particle diameter of 0.5 to 60 μm. The thermoplastic resin composition according to claim 1 or 2. 4. A viscosity ratio (A) between the thermoplastic resin (A) and the liquid crystalline polymer (B) when the shear rate is 1200 sec ⁻¹ at a processing temperature equal to or higher than the flow starting temperature of the liquid crystalline polymer (B).
The thermoplastic resin composition according to any one of claims 1 to 3, wherein η / Bη) is 0.1 or more. 5. The thermoplastic resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin (A) is a polyacetal resin. 6. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is a polyolefin (co) polymer. 7. The thermoplastic resin (A) is a styrene type (co).
It is a polymer, The thermoplastic resin composition in any one of Claims 1-4. 8. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is a polyamide (co) polymer. 9. The thermoplastic resin according to claim 1, wherein the liquid crystalline polymer (B) comprises a constitutional unit of aromatic hydroxycarboxylic acid / aliphatic diol / aromatic dicarboxylic acid. Resin composition. 10. The liquid crystalline polymer (B) comprises a constitutional unit of aromatic hydroxycarboxylic acid / ethylene glycol / terephthalic acid, and the content of aromatic hydroxycarboxylic acid is 30 to 70 mol%. The thermoplastic resin composition according to any one of claims 1 to 8. 11. The aromatic hydroxycarboxylic acid is p-
11. The compound according to claim 10, which is hydroxybenzoic acid.
The thermoplastic resin composition described. 12. The aromatic hydroxycarboxylic acid is p-
The thermoplastic resin composition according to claim 10, which is composed of hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. 13. A thermoplastic resin composition according to claim 1, wherein a molten resin has a gate passage speed of 50 at a processing temperature equal to or higher than the flow starting temperature of the liquid crystalline polymer (B).
An injection molding method for a thermoplastic resin composition, which comprises performing injection molding under the condition of 0 m / min or more. 14. The injection molding die according to claim 13, wherein a ratio S _R / S _G of the cross-sectional area S _R of the runner to the cross-sectional area S _{G of the} gate is in the range of 3 to 150. Injection molding method of thermoplastic resin composition. 15. An injection method comprising the thermoplastic resin composition according to claim 1, wherein the liquid crystalline polymer is fibrous having an average aspect ratio of 6 or more and dispersed in the matrix phase of the thermoplastic resin (A). When the injection-molded product is a molded product and is subjected to a heat treatment under a temperature condition equal to or higher than the melting point of the liquid-crystalline polymer (B) under no load, the liquid-crystalline polymer (B) has a weight-average particle size. The diameter is in the range of 10 to 40 μm, and 80% by weight or more of the diameter is 0.5 to 60 μm.
An injection-molded article characterized by being island-like micro-dispersed in the matrix phase of the thermoplastic resin (A).