JPH06306261A - Liquid crystal polyester resin composition for blow molding or extrusion molding and molded article thereof - Google Patents

Abstract

(57) [Summary] [Purpose] It has an excellent melt tension, improves the drawdown of the parison, and has excellent blow moldability and extrusion moldability.
(EN) Provided is a liquid crystalline polyester resin composition capable of easily producing a hollow molded article having mechanical properties, heat resistance, dimensional accuracy, surface condition and the like. [Structure] (A) 100 parts by weight of a melt-processable aromatic polyester containing a specific constituent unit and capable of forming an anisotropic melt phase,
(B) 0.2 to 10 parts by weight of a styrene copolymer comprising 40 to 97% by weight of styrene, 60 to 3% by weight of a glycidyl ester of a specific α, β-unsaturated acid, and 0 to 50% by weight of another vinyl monomer. , (C) one or more of fibrous, powdery, and plate-like fillers 0 to
A liquid crystalline polyester resin composition for blow molding or extrusion molding, which is prepared by mixing 100 parts by weight and melt-kneading.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a melt-processable thermoplastic polyester (liquid crystalline polyester) resin composition capable of forming an anisotropic melt phase suitable for blow molding and extrusion molding, and blow molding using this composition. The present invention relates to a hollow molded article molded by a molding method or the like.

[0002]

BACKGROUND OF THE INVENTION Liquid crystalline polyester resins are widely used as engineering plastics because they have a good balance of fluidity, mechanical strength, heat resistance, chemical resistance and electrical properties. Although used, most of them were obtained exclusively by injection molding. However, in recent years, the use of such polyester resins has tended to become more sophisticated and specialized,
It is expected that this can be molded efficiently and economically by a blow molding method or the like to obtain a hollow molded article that retains the excellent physical properties of the liquid crystalline polyester. For example, pipes, containers and the like in an automobile engine room are used in a high temperature atmosphere and are required to have high mechanical properties and the like, and therefore, those made of metal have been conventionally used exclusively. But,
In order to reduce the weight, prevent rust, reduce the processing cost, etc., it is desired to obtain these by blow molding of a liquid crystalline polyester resin having the above-mentioned excellent properties. However, while the liquid crystalline polyester resin has excellent fluidity and physical properties, it is generally the most important property for applying these blow molding methods, that is, the melt tension is low, so that the drawdown is severe and the blow molding method is difficult. Therefore, it is extremely difficult to obtain a molded product having a desired shape. As a method for improving this, a method using a highly polymerized polyester resin having a high intrinsic viscosity, a method using a branched polyester, a method of adding various fillers, and the like have been considered. Insufficient material for the processing method.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have further improved melt tension, improved drawdown of a parison, and excellent blow moldability and extrusion moldability. As a result of diligent study to obtain a liquid crystalline polyester resin composition capable of easily producing a hollow molded product having mechanical properties, heat resistance, dimensional accuracy, surface condition, etc., a small amount of a specific styrene-based copolymer was blended. By doing so, they have found that this object can be achieved, and completed the present invention. That is, the present invention, (A) the following general formula (1) and (2), containing a structural unit represented by (3), 100 parts by weight of melt-processable aromatic polyester capable of forming an anisotropic melt phase,

[0004]

[Chemical 3]

[However, -Ar ₁ -is composed of a divalent phenylene group and / or naphthalene group, and -Ar ₂ -is selected from a divalent aromatic group and an aliphatic group having 2 to 8 carbon atoms. Or two or more kinds, and -R- is a divalent aromatic group and 2 to 8 carbon atoms.
1 or 2 or more types selected from the aliphatic groups of. (B) 40 to 97% by weight of styrene, 60 to 3% by weight of glycidyl ester of α, β-unsaturated acid represented by the following general formula (4),
0.2 to 10 parts by weight of a styrene copolymer composed of 0 to 50% by weight of another vinyl monomer,

[0006]

[Chemical 4]

(In the formula, -R 'is hydrogen or an alkyl group.) (C) Blow obtained by mixing 0 to 100 parts by weight of one or more of fibrous, powdery, and plate-like fillers and melt-kneading the mixture. The present invention relates to a liquid crystalline polyester resin composition for molding or extrusion molding.

The constituent components of the composition of the present invention will be described in detail below. First, the liquid crystalline polyester resin (A) used in the present invention is an aromatic polyester containing at least 30 mol% or more of an aromatic hydroxycarboxylic acid group consisting of the general formula (1), and another general formula (2) Also included are aromatic polyethers containing 35 mol% or less of repeating units each consisting of a dicarboxylic acid group represented by and a diol represented by the general formula (3). -Ar _{1-of the} formula (1) constituting the main repeating unit of the liquid crystalline polyester used in the present invention is composed of a phenylene group and / or a naphthalene group, and the aromatic hydroxycarboxylic acid or its ester-forming compound Obtained by condensation. Examples of such an aromatic hydroxycarboxylic acid compound include 4-hydroxybenzoic acid,
2-hydroxy-6-naphthoic acid, 2-hydroxy-7
-Aromatic hydroxycarboxylic acids such as naphthoic acid and 4- (4-hydroxyphenyl) benzoic acid or ester-forming compounds thereof can be mentioned, and one kind or a mixture of two or more kinds may be used. In particular, as the structural unit (1), those having a 4-hydroxybenzoic acid group as a main component and a part thereof containing a hydroxynaphthoic acid group are preferable. In particular, when the constituent unit of the polyester (2) described below is absent or extremely small as the constituent unit of the polyester to be used, it is particularly preferable from the viewpoint of moldability that the constituent unit of the formula (1) is composed of the above two kinds. Next, -Ar _{2-of the} formula (2) constituting the polyester (A) used in the present invention is a phenylene group, a naphthalene group or a diphenylene group, and even if it is an aliphatic group within a range that maintains liquid crystallinity. Good. Further, -R- in the formula (3) is a phenylene group, a naphthalene group, a biphenylene group or the like, and may be an aliphatic group having 2 to 8 carbon atoms.
Formula (2) and (3) formula constituent units, dicarboxylic acid as a raw material
(HOOC-Ar ₂ -COOH) or its ester-forming compound and a diol (HO-R-OH), and the polycondensation reaction of the acid component and the diol component with the aromatic hydroxycarboxylic acid or its ester-forming compound. It is introduced by doing. (2) As the dicarboxylic acid component for constituting the formula unit, terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, 2,7-naphthalenedicarboxylic acid, 4,
Known aromatic dicarboxylic acids such as 4′-diphenylcarboxylic acid or ester-forming compounds thereof can be used. or,
(3) Examples of the diol for forming the formula unit include hydroquinone, nucleus-substituted hydroquinone, 4,4′-biphenol, 2,6-dihydroxynaphthalene, and bisphenol A.
One or more known aromatic diols or aliphatic diols such as ethylene glycol and cyclohexanedimethanol can be used. The liquid crystalline polyester (A) used in the present invention comprises (1) at least 30 mol% of structural units, (2) and (3) units, respectively.
35 mol% or less, preferably (1) formula 40% or more, (2)
Formula and (3) formula units are each 30% or less, more preferably (1)
50% or more of the formulas and 25% or less of the units of the formulas (2) and (3), respectively. The liquid crystalline polyester (A) used in the present invention is, in addition to the above formulas (1) and (2), (3), a comonomer component having an ether bond or an amide bond within the range showing liquid crystallinity when melted. In addition, polyfunctional ester-forming monomers such as pentaerythritol, trimellitic acid, trimesic acid, and 4-hydroxyisophthalic acid, sodium sulfoisophthalate, and para-isophthalic acid may be introduced as long as liquid crystallinity is maintained. What introduced the ester forming monomer which has an ionic group like sodium hydroxyethyl phenyl sulfonate may be used. Particularly preferred liquid crystalline polyester resin (A) is a copolymerized aromatic polyester composed of 4-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid, and an acid component composed of terephthalic acid and isophthalic acid in addition to the polyester. It is an aromatic copolyester obtained by copolymerizing a combination monomer with a diol component consisting of hydroquinone, 4,4′-biphenol and ethylene glycol.

The liquid crystalline thermoplastic polyester (A) used in the present invention can be prepared from the above-mentioned monomer compounds by a known method using a direct polymerization method or a transesterification method, but usually a melt polymerization method. And slurry polymerization method are used. The above-mentioned compounds having an ester-forming ability may be used as they are for the polymerization, or may be modified from a precursor to a derivative having the ester-forming ability at a stage before the polymerization. Various catalysts can be used in these polymerizations, and typical ones are dialkyl tin oxide, diaryl tin oxide, titanium dioxide, alkoxy titanium silicates, titanium alcoholates, alkali and alkali carboxylic acids. Examples thereof include earth metal salts and Lewis acid salts such as BF ₃ . The amount of catalyst used is generally about 0.001 to 1% by weight, especially about 0.01 to 0.2, based on the total weight of the monomers.
Weight percent is preferred. If necessary, the polymers produced by these polymerization methods can be increased in molecular weight by solid state polymerization by heating under reduced pressure or in an inert gas. The melt viscosity of the liquid crystalline polyester resin (A) used in the present invention is not particularly limited, and may be any as long as it can be injection-molded. Generally, a melt viscosity at a molding temperature of 10 MPa or more and 600 MPa or less at a shear rate of 1000 sec ^-1 can be used. The pressure is preferably 15 to 400 MPa, and even if the viscosity is low, blow molding can be performed by using the component (B) together, and the moldability is remarkably improved. However, if the viscosity itself is too high, the fluidity is extremely deteriorated, which is not preferable. The liquid crystalline polyester resin (A) may be a mixture of two or more kinds of liquid crystalline polyester.

Liquid crystalline polyester resin used in the present invention
(A) is a nematic liquid crystalline polyester that exhibits optical anisotropy when melted, and is an essential element for the present invention to have both heat resistance and easy processability. The property of the melt anisotropy can be confirmed by a conventional polarization inspection method using a crossed polarizer. Specifically, using a Leitz polarization microscope
It can be confirmed by melting the sample placed on the Leitz hot stage and observing it under a nitrogen atmosphere at a magnification of about 40 times.
When the above-mentioned optically anisotropic polymer is inserted between orthogonal polarizers, it transmits polarized light even in a molten still liquid state.

Next, the styrene copolymer as the component (B) in the present invention is blended with the base polyester resin (A) to improve the melt tension, suppress the drawdown, and significantly improve the blow moldability. Is played. The styrene copolymer as the component (B) is 40 to 97% by weight of styrene.
And a glycidyl ester of an α, β-unsaturated acid represented by the following general formula (4) in an amount of 60 to 3% by weight.

[0012]

[Chemical 5]

(In the formula, -R 'is hydrogen or an alkyl group.) (4) If the content of the glycidyl ester unit of the α, β-unsaturated acid represented by the formula is too high, the composition tends to gel. It is not preferable because it causes a problem in blow moldability and deteriorates the surface condition of the molded product. If it is too low, melt tension,
Since the effect of improving blow moldability such as drawdown property cannot be obtained, the content of the formula (4) unit in the component (B) is 60 to 3
Limited to wt%. It is preferably 50 to 5% by weight.
The glycidyl ester unit of α, β-unsaturated acid represented by the formula (4) is, for example, acrylic acid glycidyl ester,
Methacrylic acid glycidyl ester, ethacrylic acid glycidyl ester, itaconic acid glycidyl ester and the like are preferable, and methacrylic acid glycidyl ester is particularly preferable.
The styrene-based copolymer (B) may be a multi-component copolymer obtained by copolymerizing one or more vinyl monomers other than the above two components, and is suitable as the third component. Examples thereof include acrylonitrile, vinyl chloride, α-methylstyrene, brominated styrene, phenylmaleimide and the like. In particular, acrylonitrile is most suitable as the third component, and a terpolymer containing 50% by weight or less, preferably 40% by weight or less, has a further excellent effect in improving blow moldability. Although it may be a multi-component copolymer in which a small amount of other vinyl-based monomer is supplementarily introduced as a subsidiary component other than these, ethylene, propylene, butene-1
The inclusion of such olefinic components is not preferable because the effect is rather diminished. The styrene-based copolymer which is the component (B) of the present invention can be easily prepared by a usual radical polymerization method using a monomer of each component and a radical polymerization catalyst. The copolymer which is the component (B) of the present invention may be a graft copolymer in which a linear copolymer and a small amount of a vinyl-based polymer are chemically bonded in a branched or cross-linked manner. As the vinyl-based monomer that constitutes such a branched or crosslinked segment, acrylic acid, acrylic acid alkyl ester,
Methacrylic acid, methacrylic acid alkyl ester, styrene, acrylonitrile and the like can be mentioned. The copolymer having such a branched or crosslinked structure can be obtained, for example, by copolymerizing at least one kind of the vinyl-based monomer and a radical-polymerizable organic peroxide in the presence of the linear copolymer, and a copolymer containing a peroxide group. A graft copolymer can be obtained by forming a coalescence and heating and kneading this. However, the component (B) used in the present invention needs to be a substance that is fluid at least at the melt-kneading temperature, and preferably,
It is desirable to use one having a melt viscosity of the component (B) lower than that of the polyester resin (A) at the melt-kneading temperature. The viscosity of the component (B) is particularly preferably 1/2 or less of that of the component (A). Those with high molecular weight and high melt viscosity or those highly grafted have poor fluidity, poor dispersibility in polyester resin (A), and have less effect on improving blow moldability such as melt tension and drawdown. However, the surface condition of the molded product also deteriorates, which is not preferable. The blending amount of the styrene copolymer as the component (B) is 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the component (A). If the blending amount is too small, the blow moldability intended by the present invention cannot be obtained, and if the blending amount is too large, the resin composition is gelled, which is not preferable.

The liquid crystalline polyester resin composition used in the blow or extrusion molding of the present invention may further contain, as a component (C), a fibrous, powdery or tabular filler as a component (C). Such a filler is effective in imparting mechanical properties to the molded product, particularly strength and rigidity. As the fibrous filler, glass fiber, asbestos fiber, carbon fiber,
Silica fiber, silica-alumina fiber, zirconia fiber,
Boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, copper,
Examples include inorganic fibrous substances such as metallic fibrous substances such as brass. A particularly representative fibrous filler is glass fiber. On the other hand, as the particulate filler, carbon black,
Silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, iron oxide,
Oxides of metals such as titanium oxide, zinc oxide, alumina,
Examples thereof include metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, silicon nitride, boron nitride and various metal powders. Examples of the plate-like filler include mica, glass flakes, various metal foils and the like. These inorganic fillers can be used alone or in combination of two or more.
The combined use of fibrous fillers, especially glass fibers and powdery or granular or plate-like fillers is a preferable combination in terms of mechanical strength and dimensional accuracy of molded products, electrical properties, etc., and particularly improved blow moldability. It is also effective. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent. Examples of this are functional compounds such as epoxy compounds, isocyanate compounds, titanate compounds and silane compounds. The amount of the above-mentioned filler, which is the component (C) in the present invention, is 100 parts by weight or less, preferably 70 parts by weight or less, relative to 100 parts by weight of the polyester (A). If the compounding amount is small, the rigidity, strength, etc. tend to decrease,
On the other hand, if the amount exceeds 100 parts by weight, molding will be hindered, which is not preferable.

Further, in addition to the above, it is possible to supplementarily use other thermoplastic resins in the polyester resin composition of the present invention. Any other thermoplastic resin may be used as long as it is a thermoplastic resin that is stable at high temperatures. For example, polyamide polymer, polyester polymer other than the above, styrene (co) polymer other than the above, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyalkyl acrylate, polyacetal, polysulfone, polyether sulfone, polyetherimide , Polyetherketone, fluororesin, (modified) polyolefin and the like. Further, these thermoplastic resins may be used as a mixture of two or more kinds. Particularly preferable thermoplastic resins among these are polyamide resins such as nylon 6, nylon 66, nylon 12, or copolymers thereof. The blending amount of these polyamide-based resins is 100 parts by weight of the component (A).
It is preferably 100 parts by weight or less. It is particularly preferably 60 parts by weight or less. Polyamide-based resins have the effect of increasing the melt tension and stabilizing the parison and improving the drawdown resistance, but if the blending amount is too large, the characteristics of the resin of component (A) will be lost, and this is not preferred. A thermoplastic polyester polymer that does not exhibit liquid crystallinity is also a particularly preferable combined thermoplastic resin. Examples thereof include polyethylene terephthalate and bisphenol A / terephthalic acid / isophthalic acid copolymers. These polyester-based polymers are also preferably 100 parts by weight or less based on 100 parts by weight of the component (A). It is particularly preferably 60 parts by weight or less. If the blending amount of the polyester polymer is too large, the characteristics of the resin as the component (A) will be lost, which is not preferable. Furthermore, in the liquid crystalline polyester resin composition of the present invention, known substances generally added to synthetic resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, dyes and pigments, etc. A colorant, a lubricant, a release agent, a crystallization accelerator, a crystal nucleating agent, etc. can be appropriately added according to the required performance.

The composition of the present invention is prepared by the above (A) and (B).
, (C) component are added and blended and melt-kneaded, and optionally other desired components are also blended and melt-kneaded, and then subjected to blow molding. The melt-kneading of each component is 1
The pellets may be once pelletized using a twin-screw or extruder, and then blow-molded, or immediately after melt-kneading, a parison for blow-molding may be used for molding. Further, the components (A), (B), and (C) may be melt-kneaded at once, or the components may be separately kneaded and then mixed, or the components may be added in two or more times. However, it may be melt-kneaded.

The blow molding of the present invention may be carried out by a usual method using a blow molding machine generally used for blow molding of thermoplastic resins. That is, the above polyester resin composition is plasticized by an extruder or the like, and is extruded or injected by an annular die to form an annular melted or softened intermediate parison, which is sandwiched between molds to form a gas inside. Is blown, inflated, cooled and solidified, and molded as a hollow body. As the molding conditions of the liquid crystal polyester resin composition of the present invention, it is preferable that the cylinder temperature and the die temperature be within the range of -50 ° C to + 50 ° C from the melting point of the resin, and particularly preferably -40 ° C to + 30 ° C. Within the range of. The gas blown into the interior may be air, nitrogen or the like, but air is usually used in consideration of economy and the blowing pressure is 3 to 10
kg / cm ² is preferred. Further, it can be molded by a special blow molding machine such as a three-dimensional blow molding machine. It is also possible to prepare a multilayer blow-molded article by adding one or more layers of the composition of the present invention, or by combining layers of other materials.

[0018]

INDUSTRIAL APPLICABILITY The liquid crystal polyester resin composition of the present invention has an improved melt tension as compared with the conventional liquid crystal polyester resin or its composition, and there is no drawdown of the parison during blow molding. Is significantly improved, and a hollow molded product having a uniform thickness and a good appearance can be obtained. Moreover, mechanical properties, heat resistance, etc. are excellent, and the intake manifold of an automobile, intake and exhaust parts around an engine, It is possible to provide a hollow molded article that can be used under considerably severe conditions, such as containers for high-temperature liquids, chemicals, solvents, containers such as pipes and floats, and tubular objects (including irregular shapes).

[0019]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Examples 1 to 6 and Comparative Examples 1 to 2 In 100 parts by weight of the liquid crystalline polyester (A) shown in Table 1, (B)
Styrene-glycidyl methacrylate copolymer or styrene-acrylonitrile-glycidyl methacrylate copolymer as a component and (C) glass fiber were blended and melt-kneaded with a twin-screw extruder to prepare pellets of the liquid crystalline polyester resin composition. Next, using this pellet, a blow molding machine (S-45ND manufactured by Placo Co., Ltd.) was used to obtain a die diameter of 50.
mm, die spacing 3mm, average thickness 2.5mm,
A cylindrical container having an internal capacity of 500 cc was molded. At this time, the moldability (drawdown, breakage during blowing, uniformity of wall thickness of the molded product, appearance (rough skin, surface irregularities)) was evaluated. Further, for comparison, the same test was conducted in the case where the styrene copolymer (B) was not blended. The results are shown in Table 1.

The measuring methods used for evaluating the characteristic values are as follows. 1) Melt tension Using a capillary rheometer, a load cell was used to measure the load when the resin flowed out from an orifice having a diameter of 1 mm at the blow molding temperature shown in the table was dropped and taken at a ratio of 2. 2) Blow Moldability / Drawdown The drawdown index was evaluated using the ratio of the time until the length of the parison extruded from the blow molding machine reached 120 mm to the time it reached 600 mm, that is, the drawdown index. The drawdown index is 5 for a resin that has no drawdown, and approximately 1 for a resin that draws down instantly.・ Breakage at the time of blowing Judgment was made based on whether or not the material was visually torn during blow molding.・ Uniformity of wall thickness of molded product Cut the molded product and measure the thickness at 3 places in each of the upper part, the center part and the lower part of the cylinder with a micrometer and change the thickness (maximum value and minimum value with respect to average wall thickness). % Difference) was examined. -Appearance The surface smoothness (irregularities) was visually observed and ranked as excellent, good or bad. The components (A) and (B) in the table are as follows. (A) ingredient

[0021]

[Chemical 6]

Component (B) S / G styrene / glycidyl methacrylate S / AN / G styrene / acrylonitrile / glycidyl methacrylate (others) PET: polyethylene terephthalate NY6: nylon-6

[0023]

[Table 1]

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Claims (5)

[Claims] 1. (A) 100 parts by weight of a melt-processible aromatic polyester containing a structural unit represented by the following general formulas (1) and (2) and (3) and capable of forming an anisotropic melt phase: Chemical 1] [Wherein -Ar ₁ -is a divalent phenylene group and / or a naphthalene group, and -Ar ₂ -is a divalent aromatic group and a carbon number of 2
To one or more selected from aliphatic groups having 8 to 8 carbon atoms, and -R- is from one or more selected from divalent aromatic groups and aliphatic groups having 2 to 8 carbon atoms. Become. (B) 40 to 97% by weight of styrene, 60 to 3% by weight of glycidyl ester of α, β-unsaturated acid represented by the following general formula (4),
0.2 to 10 parts by weight of a styrene copolymer composed of 0 to 50% by weight of another vinyl monomer, (In the formula, -R 'is hydrogen or an alkyl group.) (C) For blow molding, which is prepared by blending 1 to 100 parts by weight of one or more of fibrous, powdery, and plate-like fillers and melt-kneading or A liquid crystalline polyester resin composition for extrusion molding. 2. The --Ar ₁ -group of the formula (1) in the component (A) is 1,4
The liquid crystalline polyester resin composition for blow molding or extrusion molding according to claim 1, which comprises a phenylene group, a 2,6- (or 2,7-) naphthalene group, or a combination thereof. 3. The component (A) wherein the --Ar ₂ --group of the formula (2) is 1,4
-(Or 1,3-) phenylene group or 2,6- (or 2,7)
-) Naphthalene group, and -R- in formula (3) is a 1,4-phenylene group, 4,4'-biphenyl group, 2,6- (or 2,7-) naphthalene group or ethylene group. Item 1. A liquid crystalline polyester resin composition for blow molding or extrusion molding according to item 1 or 2. 4. The styrene copolymer (B) is at least one of acrylonitrile, vinyl chloride, α-methylstyrene, brominated styrene and phenylmaleimide, in addition to styrene and glycidyl ester of α, β-unsaturated acid. The blow-moldable or extrusion-moldable liquid crystalline polyester resin composition according to any one of claims 1 to 3, which is a copolymer containing a. 5. A hollow molded article produced by blow molding using the polyester resin composition according to any one of claims 1 to 4.