JPH08118398A - Injection-molded product - Google Patents

Abstract

PURPOSE: To improve mechanical strength, by a method wherein a composition of thermoplastic resin and a liquid crystalline polymer, in which the crystalline polymer is dispersed into a matrix phase of the thermoplastic resin in a specific state is used for injection molding and the state is specified at the time of the injection molding. CONSTITUTION: An injection-molded product of a thermoplastic resin composition comprises 99-50wt.% thermoplastic resin which does not form an anisotropic molten phase and a 1-50wt.% liquid crystalline polymer which is formable of the anisotropic molten phase. The liquid crystalline polymer is dispersed into the matrix phase of the thermoplastic resin under a fibrous state of a mean aspect ratio of at least 6. When an injection-molded product is cooled by passing through melting under a temperature state of at least the melting point of the liquid crystalline polymer under no-load, the liquid crystalline polymer is within the range of weight mean particle diameter of 10-40μm and at least its 80wt.% is dispersed microscopically in an insular state into a matrix phase of the thermoplastic resin so that at least its 80wt.% is within the range of particle diameter of 0.5-60μm. Melt viscosity under a specific condition wherein the bending modulus of elasticity is at least 40000kg/cm<2> is taken as the range within 400-2500 poises.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an injection molding of 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. Regarding goods.

[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 that has many characteristics such as high heat resistance and easy moldability due to high fluidity when melted, the mechanical shrinkage rate differs in the mechanical shrinkage rate in the direction perpendicular to the molecular chain orientation,
There are also commercial disadvantages such as higher prices. On the other hand, a thermoplastic resin that does not form an anisotropic molten phase is relatively inexpensive, but has the disadvantage that the physical properties such as heat resistance and rigidity are inferior to those of the liquid crystalline polyester. 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. However, in an injection-molded article made of a thermoplastic resin composition obtained by simply blending the two, the high strength of the liquid crystalline polymer,
Properties such as high rigidity, heat resistance, and easy moldability (high fluidity) are not utilized, and the mechanical strength thereof is significantly reduced.
This is because the cause of the high mechanical properties of the liquid crystalline polymer is the molecular orientation and fiberization due to the shear stress and the stretching stress during the melt processing. This is because in a thermoplastic resin composition simply blended with, even if molded, most liquid crystalline polymers are spherically dispersed with the thermoplastic resin as a matrix except for the surface layer, which does not have a reinforcing effect. . Therefore, if the proportion of the liquid crystalline polymer is increased and the amount of the thermoplastic resin is reduced, then the liquid crystalline polymer becomes a matrix and the thermoplastic resin is dispersed in an island shape, but the advantage of the thermoplastic resin can be utilized. It is not possible to do so and has little utility value. Therefore, JP-A-5-7070
As described in JP-A No. 0-112709 and JP-A No. 5-112709, first, the liquid crystalline polymer is extruded while being stretched at a temperature at which the liquid crystalline polymer and the thermoplastic resin are both melted, so that the aspect ratio of the liquid crystalline polymer is previously set. (Length / thickness)
Prepare the molding material so that it exists in the form of large fibres,
When molding a molded product, a molding containing a fibrous liquid crystalline polymer having a reinforcing effect is produced by molding the molding material at a temperature at which only the thermoplastic resin melts without melting the liquid crystalline polymer. I thought of a way to do it. However, in these, extrusion is performed while stretching in advance, and the melt extrudate is further stretched by a roller or the like to form a composition in a state where the liquid crystalline polymer is oriented in a fibrous state, and then a molded product is formed by injection molding or the like. When it is obtained, it is molded at a molding temperature below the melting point of the liquid crystalline polymer. Alternatively, when a molded product is produced from the beginning, a considerably large shearing force must be applied when the resin composition is filled in the mold to orient 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.

[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 It is extremely important to use a composition in which the liquid crystalline polymer (B) is dispersed in the matrix phase of the thermoplastic resin (A) in a specific state in injection molding, and in the injection molding By specifying the conditions, the liquid crystalline polymer (B) can easily be made into fibers, exhibiting an extremely high reinforcing effect that has never been seen, and therefore the properties of the obtained molded product are unique, and especially the thin wall with excellent mechanical strength. We found that it could be a molded product and completed the present invention.

That is, according to the present invention, 99-50% by weight of a thermoplastic resin (A) which does not form an anisotropic molten phase and 1-50% by weight of a liquid crystalline polymer (B) which can form an anisotropic molten phase. An injection molded article of a thermoplastic resin composition comprising (both total 100% by weight), wherein (1) the liquid crystalline polymer (B) is a fibrous thermoplastic resin (A) matrix having an average aspect ratio of 6 or more. When dispersed in the phase, (2) the injection-molded product is melted under a temperature condition not lower than the melting point of the liquid crystalline polymer (B) under no load, and the liquid crystalline polymer (B) has a weight average particle diameter of 10 when cooled. To 40 μm, and 80% by weight or more of which is micro-dispersed in an island shape in the matrix phase of the thermoplastic resin (A) so that the particle size is in the range of 0.5 to 60 μm, and (3) injection molding. ASTM D
Flexural modulus measured according to 790 is 40,000 kg /
cm ² or more, and (4) a temperature at which the injection-molded product is remelted and is 20 ° C. higher than the melting point of the liquid crystalline polymer (B),
There is provided an injection-molded article characterized in that the melt viscosity measured under a shear rate of 1200 sec ^-1 is in the range of 400 to 2500 poise. Further, according to the present invention, there is provided the injection-molded article, wherein the thermoplastic resin (A) is a polyester resin. Further, according to the present invention, there is provided the injection-molded article, wherein the thermoplastic resin (A) is a polycarbonate resin. Further, according to the present invention, there is provided the above-mentioned injection-molded article, which is a thin-walled article in which 50% or more of the thickness of the article is 1 mm or less. Further, according to the present invention, there is provided the injection-molded article which is a housing of an electronic device. Furthermore, according to the present invention, there is provided the injection-molded article, wherein the electronic device is any one of a personal computer, a mobile phone, a connector, a CD pickup part, a hard disk and components around them.

The thermoplastic resin (A) to which the present invention is applied is, for example, polyethylene, polypropylene or poly-4.
-Polyolefin-based (co) polymers such as methyl-1-pentene, polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate and polycarbonate resins, polyamide-based polymers, ABS resins, polyarylene sulfide resins, polyacryl acrylates, polyacetals and Resins and the like that are mainly composed of these,
You may use 1 type, or 2 or more types. Among these, polyester resins such as polycarbonate resin, polybutylene terephthalate and polyethylene terephthalate are preferable.

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. The thermoplastic resin provided with is also included in the range of the thermoplastic resin in the present invention.

The liquid crystalline polymer (B) refers to a melt-processable polymer having a property capable of forming an optically anisotropic molten phase, and polymer molecules are regularly aligned in parallel when subjected to shear stress in a molten state. It has the property of taking
Such polymer molecules are generally elongated, flattened, fairly stiff along the long axis of the molecule, and have multiple chain extension bonds, usually in either coaxial or parallel relationship. Is. The properties of the anisotropic melt phase are
It can be confirmed by a conventional polarization inspection method using a crossed polarizer. More specifically, the confirmation of the anisotropic molten phase can be performed by using a Leitz polarization microscope and observing the molten sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The liquid crystalline polymer to which the present invention is applicable, when examined between orthogonal polarizers,
Polarized light is normally transmitted even if it is in a stationary state and is optically anisotropic.

The liquid crystalline polymer (B) as described above is not particularly limited, but is preferably an aromatic polyester or an aromatic polyesteramide, and the aromatic polyester or the aromatic polyesteramide is partially contained in the same molecular chain. Polyesters contained in are also in that range. These have a concentration of 0.1 in pentafluorophenol at 60 ° C.
When dissolved in weight percent, preferably at least about 2.
0 dl / g, more preferably 2.0 to 10.0 dl /
Those with a logarithmic viscosity (IV) of g are used.

Liquid crystalline polymer (B) applicable to the present invention
Particularly preferably as the aromatic polyester or aromatic polyester amide as, an aromatic polyester having at least one compound selected from the group of aromatic hydroxycarboxylic acid, aromatic hydroxyamine, and aromatic diamine as a constituent component, It is an aromatic polyester amide. More specifically, (1) a polyester mainly composed of one or more aromatic hydroxycarboxylic acids and their derivatives; (2) mainly (a) one or two aromatic hydroxycarboxylic acids and their derivatives. And (b) one or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and their derivatives, and (c) at least one of aromatic diols, alicyclic diols, aliphatic diols and their derivatives Or a polyester consisting of two or more kinds; (3) mainly (a) one or more kinds of aromatic hydroxycarboxylic acid and its derivative, and (b)
A polyesteramide comprising one or more aromatic hydroxyamines, aromatic diamines and their derivatives, and (c) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids and their derivatives; (4) Mainly (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic hydroxyamines, aromatic diamines and their derivatives, and (c) One or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and their derivatives, and (d) at least one or more of aromatic diols, alicyclic diols, aliphatic diols and their derivatives, and And polyester amide. Further, if necessary, a molecular weight modifier may be used in combination with the above constituent components.

Preferable examples of specific compounds constituting the liquid crystalline polymer (B) applicable to the present invention include:
aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene,
4,4'-dihydroxybiphenyl, hydroquinone,
Resorcin, the following general formula [1] and the following general formula [2]
An aromatic diol such as a compound represented by: terephthalic acid,
Isophthalic acid, 4,4'-diphenyldicarboxylic acid,
Aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid and compounds represented by the following general formula [3]; p-
Aromatic amines such as aminophenol and p-phenylenediamine are mentioned.

[0011]

Embedded image

A particularly preferred liquid crystalline polymer (B) applicable to the present invention is an aromatic polyester containing p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid as constituent units.

The thermoplastic resin composition constituting the injection-molded article of the present invention comprises the thermoplastic resin (A) and the liquid crystalline polymer (B). Regarding the composition ratio of the thermoplastic resin (A) and the liquid crystalline polymer (B), the former is 99 to 5
0% by weight, preferably 90-60% by weight, the latter 1-5
It is 0% by weight, preferably 10 to 40% by weight (the total of both is 100% by weight). When the composition ratio of the liquid crystalline polymer (B) is in the range of 1 to 50% by weight, the matrix phase described later will not be inverted, and the thermoplastic resin (A) can be reinforced by the liquid crystalline polymer (B). Become. Further, when the composition is melted and cooled under a temperature condition not lower than the melting point of the liquid crystalline polymer under no load, and the resulting composition is observed, the liquid crystalline polymer (B) is a thermoplastic resin (A).
It is necessary that they are micro-dispersed like islands in the matrix phase. The dispersion state of the liquid crystalline polymer (B) is in the range of 10 to 40 μm in weight average particle size, particularly preferably in the range of 0.5 to 60 μm, and 80% by weight or more of the liquid crystalline polymer (B) is 5 to 5 μm. It is in the range of 50 μm.

The melting is a means for making the liquid crystalline polymer (B) into a spherical shape which is easy to observe even if the liquid crystalline polymer (B) is dispersed in a shape other than a spherical shape, and the melting temperature should be equal to or higher than the melting point of the liquid crystalline polymer (B). However, in order to completely melt the liquid crystalline polymer, it is preferable that the liquid crystalline polymer is allowed to stand at a temperature higher than the melting point by 10 ° C. or more and for 1 minute or more, particularly 3 to 5 minutes. When the dispersion having a shape other than the spherical shape remains, the melt holding time may be extended or the particle diameter converted into the spherical shape may be used.

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-mentioned melting, 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. To obtain the above-mentioned dispersed thermoplastic resin composition, a liquid crystalline polymer (B ) And a thermoplastic resin (A), but depending on the combination, a method of using a dispersion aid, a method of repeating melt-kneading extrusion, a method of pulverizing the resin before melt-kneading, etc. are selected as appropriate. You can Among these, the method of using a dispersion aid is preferable from the viewpoint of easily obtaining the above-mentioned microdispersed thermoplastic resin composition. Preferable examples of the use of such a dispersion aid include (B) an aromatic polyester or an aromatic polyesteramide as the liquid crystalline polymer, especially the former, and the thermoplastic resin (A).
Examples of the combination include a combination using a polyester resin, particularly a polycarbonate resin.

The dispersion aid is preferably a phosphorus compound, and examples thereof include phosphides, phosphoric acid compounds and phosphorous acid compounds, and tetrakis (2,4-di-t-butylphenyl) -4,4. '-Biphenylene phosphite, bis (2,4,6-di-t-butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-t
-Butyl-4-methylphenyl) pentaerythritol-diphosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are exemplified, but a phosphite compound is preferable, and a pentaerythritol type suboxide is particularly preferable. Phosphoric acid compounds are preferred.

The amount of the dispersion aid, particularly the phosphorus compound, is 100 in total of the thermoplastic resin (A) and the liquid crystalline polymer (B).
The amount is preferably 0.01 to 0.5 part by weight, more preferably 0.05 to 0.3 part by weight, based on the weight.

In the thermoplastic resin composition used for producing the injection-molded article of the present invention, the liquid crystalline polymer (B) is micro-dispersed to the extent as described above when melted and cooled. The above-mentioned JP-A-5-11
The liquid crystalline polymer (B) may be fiberized in the composition as disclosed in JP-A No. 2709 and JP-A No. 5-70700, but such fiberization 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 product, and particularly thin-walled injection-molded products compared with molded products obtained by a known method with the composition ratio of the same liquid crystalline polymer (B). Even so, high strength and high rigidity are exhibited.

Next, the injection molding method for obtaining the injection molded article 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. It is necessary to obtain such an injection molded product. The first injection molding condition is to set the temperature (resin temperature) of the thermoplastic resin composition at the time of injection to the melting point of the liquid crystalline polymer (B) or higher, preferably 10 ° C. higher than the melting point. Due to this temperature condition, during injection molding, when the molten thermoplastic resin composition passes through the gate leading to the mold cavity of the injection molding machine, 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, by this fiberization, the dispersion state sufficiently exhibits the function, and an injection molded product having high rigidity and high strength can be obtained. The liquid crystalline polymer (B) micro-dispersed in the form of islands is stretched in the matrix phase of the thermoplastic resin (A) to be 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 is 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 energy saving and prevention of thermal decomposition of the thermoplastic resin composition, the upper limit of the temperature is preferably the thermal decomposition temperature of the liquid crystalline polymer (B) or less, particularly preferably the melting point of the liquid crystalline polymer (B) plus 50 ° C. or less. Hold down.

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 it at a rate of more than 100,000 m / min.

The mold used for the injection molding has 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 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. 2 depending on the type of gate. A gate with a shape not shown in the figure
It can be defined similarly. In the case of the side gate and the film gate of FIG. 2A and the overlap gate of FIG. 2B, S _G = S _Y when S _X > S _Y and S _X <
When S _Y , S _G = S _X , and when S _X = S _Y , S _G = S
_X = S _Y. For pin gate in FIG. 2 (c), when the cross-sectional area S _X> S _Y is S _R = S _X, if the S _X <S _Y is _{S R = S Y, S X} = S Y Then S _R = S _X = S _Y. In the case of the direct gate of FIG. 2D, 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. 2E, 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 of the figure is S _{R.
Let G.}

The resin pressure at the time of injection molding is appropriately set so as to satisfy the speed condition of the molten thermoplastic resin composition passing through the gate, but 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 of the present invention 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. are doing. Further, when the molded article dispersed in the fibrous state is melted under a temperature condition of the melting point of the liquid crystalline polymer (B) or higher without any load, the fibrous liquid crystalline polymer (B) is relaxed and cooled. The liquid crystalline polymer (B) has an island-like shape in the matrix phase of the thermoplastic resin (A) such that the weight average particle diameter is in the range of 10 to 40 μm and 80% by weight or more thereof is in the particle diameter in the range of 0.5 to 60 μm. A major feature is that they are micro-dispersed.
The melting temperature and holding time in this case are also the same as in the case of the raw material thermoplastic resin composition. Liquid crystalline polymer (B) observed when the above-described thermoplastic resin composition used in the present invention is melted under a temperature condition equal to or higher than the melting point of the liquid crystalline polymer (B) without any load and then cooled. The dispersion itself of (1) usually hardly changes even when it is re-kneaded and passed through the gate under the above injection molding conditions, so the injection molded product is melted as described above and the dispersion of the liquid crystalline polymer (B) is observed. However, the same dispersed state as that of the thermoplastic resin composition as the raw material can be obtained.

The injection-molded article according to the present invention is AST
Flexural modulus of 40,000 measured according to MD 790
It is at least kg / cm ² . The fact that this value is in the above range reflects the degree of microdispersion of the liquid crystalline polymer (B) and the degree of reinforcing effect by fiberization, and if there is no bending elastic modulus of this degree, it is used for a housing. Is impossible. The upper limit is not particularly limited, but usually 15
It is less than 50,000 kg / cm ² .

Furthermore, the injection-molded product of the present invention is easy to mold because it has good fluidity when it is manufactured by injection molding. This is because the injection-molded product is remelted and the melting point of the liquid crystalline polymer (B) is increased. Plus 10 ℃ temperature, shear rate 1200s
Melt viscosity measured under the condition of ec ^-1 is 400 to 2,50
It is characterized by being in the range of 0 poise, in particular 500-1,500 poise. Therefore, in order to efficiently manufacture an injection-molded product, it is necessary that the viscosity at the time of remelting the product is within the above range.

In the injection-molded article according to the present invention having such properties, the liquid crystalline polymer (B) is very well dispersed in the matrix phase of the thermoplastic resin (A), and they are formed into fibers with a large aspect ratio. It has high rigidity,
It can maximize its high strength and is especially suitable for improving the mechanical properties of thin-walled molded products.

As described above, the injection-molded article of the present invention contains the liquid crystalline polymer (B) contained therein in a fibrous form and has a reinforcing action. Therefore, the filler usually blended for reinforcement is Although not required, known fibrous, powdery, plate-like or hollow fillers may be blended within a range that does not impair the effects of the present invention depending on the application.

The injection-molded article of the present invention is excellent in mechanical properties even if it is thin. Therefore, in the injection-molded article of the present invention, 50% or more of the wall thickness, more preferably 70% or more, is 1 mm.
The effect is maximized when the following thin-walled molded product is used. Examples of such a thin-walled injection-molded article include a housing of an electronic device, and it is particularly preferable that it is any one of a personal computer, a mobile phone, a connector, a CD pickup part, a hard disk, and components around them.

[0029]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. The method of evaluating the injection-molded product is as follows.

(Flexural Modulus) A mobile phone type molded product as shown in FIG. 1 is molded, and a shaded portion is cut out to obtain ASTM D79.
The flexural elastic modulus (kg / cm ² ) was measured according to 0. (Average Aspect Ratio of Fibrous Liquid Crystalline Polymer) A mobile phone type molded product as shown in FIG. 1 was molded, the molded product was cut so that a plane parallel to the flow direction was exposed, and the cross section was mirror-polished. The surface was observed by an electron microscope and evaluated. 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 result is that the average aspect ratio is 8 or more, and the average aspect ratio is 8
Those having an average aspect ratio of less than 6 are represented by Δ and those having an average aspect ratio of less than 6 are represented by x. (Dispersion particle diameter of liquid crystalline polymer (B)) A part of the molded test piece was heated to 10 ° C from the melting point of the liquid crystalline polymer in a nitrogen stream.
Heat to high temperature, hold at that temperature for 3 minutes, then cool. The cut surface of the sample after heating was observed and evaluated by an electron microscope. The diameter of 50 particles of the liquid crystalline polymer arbitrarily selected was measured, and the weight average particle diameter was obtained. (Melt Viscosity) A mobile phone type molded product was crushed and the melt viscosity under a shear stress of 1200 sec ⁻¹ was measured at a temperature 20 ° C. higher than the melting point of the liquid crystalline polyester using a Capillograph manufactured by Toyo Seiki.

Example 1 A polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc., Iupilon S3000) and a liquid crystalline polyester {p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid (molar ratio 70:30) are constituted. Melting point of monomer 280 ° C, logarithmic viscosity 5.7 (dl / g)
Shows the liquid crystalline polyester of. The same applies hereinafter. } And a resin component having a mixing ratio of 6: 4 with 0.3 part by weight of bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite as a phosphite. Then, the mixture was melt-kneaded at a resin temperature of 300 ° C. with a 30 mm twin-screw extruder and pelletized. Then
Injection molding machine (gate size: 0.5 x 40)
mm; Runner cross-sectional area: 60 mm ² ) molding temperature 30
The mobile phone type molded product shown in FIG. 1 was molded at 0 ° C., and the mechanical properties, melt viscosity, average aspect ratio of liquid crystalline polyester, and weight average particle size were evaluated. The results are shown in Table 1.

Example 2 100 parts by weight of a resin component having a mixing ratio of 8: 2 of a polycarbonate resin (Iupilon S3000 manufactured by Mitsubishi Gas Chemical Co., Inc.) and a liquid crystalline polyester was mixed with bis (2) as a phosphite ester. 0.3 parts by weight of 6,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite were blended and melt-kneaded at a resin temperature of 300 ° C. with a 30 mm twin-screw extruder to form pellets. Then, the pellets are injection molded (gate size:
0.5 × 40 mm; runner cross-sectional area: 60 mm ² ) at a molding temperature of 300 ° C. to mold the mobile phone type molded product shown in FIG. 1, and then mechanical properties, melt viscosity, average aspect ratio of liquid crystalline polyester, and weight average. The particle size was evaluated. The results are shown in Table 1.

(Comparative Example 2) Polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc., Iupilon S3000) and liquid crystalline polyester were blended in a mixing ratio of 6: 4 and 3
It was melt-kneaded at a resin temperature of 300 ° C. with a 0 mm twin-screw extruder and pelletized. Then, the pellets are injection-molded (gate size: 0.5 × 40 mm; runner cross-sectional area:
The cell phone type molded product shown in FIG. 1 was molded at 60 mm ² ) at a molding temperature of 300 ° C., and the mechanical properties, melt viscosity, average aspect ratio of liquid crystalline polyester and weight average particle size were evaluated. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

INDUSTRIAL APPLICABILITY As described in detail above, the injection-molded article of the present invention obtained by injection-molding under a specific molding condition using a specific thermoplastic resin composition can be obtained by a conventional technique of the same kind. It contains a dispersed fibrous liquid crystalline polymer which has not been obtained, has a feature of extremely high rigidity and high strength, and is particularly preferably applied to a thin-walled molded product, particularly to a housing of an electronic device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a mobile phone type molded product molded in an example.

FIG. 2 is an explanatory diagram of cross-sectional areas of a gate and a runner.

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Claims (6)

[Claims] 1. A thermoplastic resin (A) that does not form an anisotropic melt phase (99 to 50% by weight) and a liquid crystalline polymer (B) that can form an anisotropic melt phase (1) to 50% by weight (total of 100 of both).
%)), Which is an injection-molded article of a thermoplastic resin composition comprising (1) a liquid crystalline polymer (B) dispersed in a matrix phase of a thermoplastic resin (A) in a fibrous form having an average aspect ratio of 6 or more, (2) The injection-molded article is loaded with the above liquid crystal polymer (B)
The liquid crystalline polymer (B) has a weight average particle diameter in the range of 10 to 40 μm and is 80% by weight or more of the particle diameter in the range of 0.5 to 60 when the liquid crystalline polymer (B) is cooled through melting under a temperature condition of not less than the melting point of
The thermoplastic resin (A) is micro-dispersed in the matrix phase of the thermoplastic resin (A) so as to be in the range of (3), and (3) the flexural modulus of the injection-molded product measured according to ASTM D790 is 40,000 kg / cm ² or more. Yes, (4) re-melting the injection-molded article, and the temperature is 20 ° C. higher than the melting point of the liquid crystalline polymer (B), and the shear rate is 1200.
Melt viscosity measured under the condition of sec ^-1 is 400 to 2.5
An injection-molded product characterized by being in the range of 00 poise. 2. The injection-molded article according to claim 1, wherein the thermoplastic resin (A) is a polyester resin. 3. The injection-molded article according to claim 1, wherein the thermoplastic resin (A) is a polycarbonate resin. 4. The injection-molded article according to claim 1, wherein 50% or more of the thickness of the molded article is a thin-walled article having a thickness of 1 mm or less. 5. The housing of an electronic device according to claim 1.
The injection-molded article according to any one of 4 above. 6. The injection-molded article according to claim 5, wherein the electronic device is any one of a personal computer, a mobile phone, a connector, a CD pickup part, a hard disk and components around them.