JP2007326885A - Tubular molded article and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a tubular molded article having a good mechanical strength. <P>SOLUTION: This method for producing the tubular molded article obtained from a resin composition containing a liquid crystalline resin and showing ≤80% molecular degree of orientation in the length direction of the tubular molded article by a crystalline orientation analysis with a wide angle X-ray diffraction of a cut open sample of the tubular molded article is provided by melt-extruding the resin composition containing the liquid crystalline resin from a ring-formed die, extending the tube diameter to 1.3 to 5.0 folds of the die slip diameter before the solidification of the molten resin composition so as to orient the liquid crystalline resin contained in the resin composition in 2 directions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tubular molded article made of a resin composition containing a liquid crystal resin, which has excellent heat resistance, gas barrier properties, gasoline barrier properties, appearance, and the like, and a method for producing the same.

  In recent years, in the fields of automobiles, food, beverages, electrical / electronic, medical or industrial chemicals, it has advantages such as lightness, molding processability, strength, freedom of design, etc. Resin tubes are widely used, but the market demands higher performance tubes. Particularly in the automobile field, a resin tube having excellent mechanical properties, gasoline barrier properties, alcohol barrier properties, carbon dioxide gas barrier properties, and heat resistance is required.

  Since the liquid crystal resin is rigid, it does not entangle even in the molten state, forms a polydomain having a liquid crystal state, and exhibits a behavior in which molecular chains are remarkably aligned in the flow direction by a low shear force. Due to intermolecular interaction and molecular orientation, industrialization as a material having functions such as gas barrier properties in addition to the well-known properties such as high strength, high elastic modulus and high heat resistance has been expected. On the other hand, when the molecules are oriented in the molten state by strong intermolecular interaction, the anisotropy is increased, and there is a problem that it is extremely difficult to obtain a molded body, particularly a tubular molded body.

  Inflation molding has long been proposed as a molding method for eliminating the anisotropy of liquid crystal resins (see Patent Documents 1 and 2). However, with inflation molding, it is possible to obtain a film in which anisotropy is eliminated. However, due to the rigidity of the liquid crystal resin, folds are likely to occur when the film is folded, and the portion that can be used as a product is reduced.

In order to solve this problem, using a blowing die whose shape of the ring-shaped slit in the blowing die has an ellipse, and the length of the major axis is twice or more the length of the minor axis, A technique for manufacturing a biaxially oriented film (see Patent Document 3), in order to eliminate anisotropy, molding using equipment that has been devised in a complicated way to shape the resin flow path so as to be oriented in different directions within the die is proposed. (See Patent Document 4).
JP 56-46728 A JP-A-61-102234 JP 62-44423 A JP-A-6-155543

  Since the liquid crystal resin has molecular chains that are remarkably aligned in the flow direction, the melt viscosity is lowered even by a slight shear force, and the melt tension at the time of melting is extremely low. For this reason, molding processability is poor, and further, since the molecules are oriented, it is difficult to achieve a balance between vertical and horizontal performances. In extreme cases, tearing occurs in the molecular orientation direction, resulting in insufficient mechanical strength. Further, in the conventional inflation molding, when the tube is folded, it is easy to generate a crease due to its rigidity, and it is difficult to obtain a tube having a good appearance. Such a problem is not solved by the inventions of Patent Documents 3 and 4.

  An object of the present invention is to provide a tubular molded article having small anisotropy and excellent mechanical strength, and a method for producing the same.

  The present invention provides a tube-shaped molded body obtained from a resin composition containing a liquid crystal resin as a means for solving the problem, and the tube-shaped molded body is obtained by crystal orientation analysis of wide-angle X-ray diffraction of a sample obtained by opening the tube-shaped molded body. Provided is a tubular shaped product having a degree of molecular orientation in the length direction of the shaped product of 80% or less.

  Further, the present invention provides a method for producing a tubular molded body according to any one of claims 1 to 3, as a means for solving another problem, wherein a resin composition containing a liquid crystal resin is melt-extruded from a ring-shaped die, Before the molten resin composition is solidified, the tube diameter is expanded to 1.3 to 5.0 times the die slip diameter so that the liquid crystal resin contained in the resin composition is oriented in two directions. A method for producing a molded body is provided.

  Since the tubular molded body manufactured by the manufacturing method of the present invention does not have molecular orientation in only one direction of the liquid crystal resin, anisotropy can be reduced as compared with the conventional liquid crystal resin molded body. For this reason, it is possible to increase the mechanical strength while maintaining the low gas permeability that is a characteristic of the liquid crystal resin.

<Resin composition containing liquid crystal resin>
The liquid crystal resin used in the present invention is called a thermotropic liquid crystal polymer and forms an anisotropic melt at a temperature of 400 ° C. or lower, and is confirmed by the “liquid crystallinity” test described in the examples. It is. The liquid crystal resin is preferably a liquid crystal polyester composed of a combination of elements of only carbon, hydrogen and oxygen, particularly in a field where easy disposal such as incineration after use is required from the viewpoint of environmental problems. Specifically, the following liquid crystal polyesters (1) to (4) can be mentioned.
(1) A combination of an aromatic dicarboxylic acid, an aromatic diol, and an aromatic hydroxycarboxylic acid.
(2) A combination of different kinds of aromatic hydroxycarboxylic acids.
(3) A combination of an aromatic dicarboxylic acid and a nucleus-substituted aromatic diol.
(4) Those obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate.

  In addition, you may use those ester-forming derivatives instead of these aromatic dicarboxylic acid, aromatic diol, and aromatic hydroxycarboxylic acid.

  Examples of the repeating units of the liquid crystalline polyester include repeating units derived from the following aromatic dicarboxylic acids, repeating units derived from aromatic diols, and repeating units derived from aromatic hydroxycarboxylic acids. It is not limited to these.

  Repeating structural units derived from aromatic dicarboxylic acids:

  Repeating structural units derived from aromatic diols:

  Repeating structural units derived from aromatic hydroxycarboxylic acids:

  Particularly preferred liquid crystal polyester from the balance of heat resistance, mechanical properties and processability

The repeating structural unit is more preferably included and at least 30 mol% or more of the repeating structural unit is more preferably included. Specifically, the combination of repeating structural units is preferably any of the following (I) to (VI).

  Among these, a combination of (I), (II) and (IV) is preferable, and a combination of (I) and (II) is more preferable.

  As the liquid crystal resin, a wholly aromatic polyester amide liquid crystal resin can be used.

  As the liquid crystal resin used in the present invention, a commercially available liquid crystalline polyester resin can be used. Specifically, “Vectra” (Polyplastics Co., Ltd.), “Siberus” (Toray Industries, Inc.), “ “Rod Run” (Unitika Ltd.), “Sumika Super” (Sumitomo Chemical Industries Ltd.), and the like.

  The resin composition containing the liquid crystal resin used in the present invention is composed of 99 to 70% by mass of the above-described (A) wholly aromatic polyester and / or wholly aromatic polyester amide liquid crystal resin, and (B) a polymer 1 to 30 containing an epoxy group. The resin composition has a melt viscosity of 50 to 4000 Pa · s at a shear rate of 1000 / sec at a temperature 20 ° C. higher than the melting point of the liquid crystal resin, and melts at a take-up rate of 15 m / min. Those having a tension of 20 mN or more are preferred.

  (B) The polymer containing the epoxy group of a component can mention the copolymer which consists of the glycidyl ester of (alpha), (beta) -unsaturated acid, and (alpha) -olefins.

  The glycidyl ester of α, β-unsaturated acid has the general formula

(In the formula, R is a hydrogen atom or a lower alkyl group.)
The compound shown by these is preferable, More preferably, they are glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, etc. Among them, glycidyl methacrylate is especially preferable.

  The copolymerization amount (feed amount) of the glycidyl ester of α, β-unsaturated acid is suitably in the range of 1 to 50 mol%. Furthermore, if it is 40 mol% or less, vinyl ethers which are unsaturated monomers copolymerizable with the above copolymer, vinyl esters such as vinyl acetate and vinyl propionate, acrylic acid such as methyl, ethyl and propyl, and Methacrylic acid esters, acrylonitrile, styrene or the like may be copolymerized.

  As the α-olefins, those having 2 to 4 carbon atoms are preferable, and specific examples include ethylene, propylene, butene-1, etc. Among them, ethylene is preferable.

The polymer containing the epoxy group as the component (B) is partially
(I) a modified ethylene polymer obtained by grafting an unsaturated carboxylic acid or a derivative thereof to a copolymer composed of ethylene and an α-olefin having 3 or more carbon atoms;
(Ii) one or more kinds selected from a modified ethylene polymer obtained by grafting an unsaturated carboxylic acid or a derivative thereof to a copolymer composed of ethylene, an α-olefin having 3 or more carbon atoms and a non-conjugated diene. An olefin polymer can be substituted.

  Examples of the α-olefin having 3 or more carbon atoms include propylene, butene-1, pentene-1, 3-methylpentene-1, and octacene-1, among which propylene and butene-1 are preferable.

  Non-conjugated dienes include 5-methylidene-2-norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-isopropenyl-2-norbornene, and 5-crotyl. 2-norbornene, 5- (2-methyl-2-butenyl) -2-norbornene, 5- (2-ethyl-2-butenyl) -2-norbornene, 5-methacryl norbornene, 5-methyl-5-vinyl Norbornene compounds such as norbornene, dichloropentadiene, methyltetrahydroindene, 4,7,8,9-tetrahydroindene, 1,5-cyclooctadiene, 1,4-hexadiene, isoprene, 6-methyl-1,5- Heptadiene, 11-ethyl-1,1,1-tridecadiene and the like, preferably 5- Chiriden -2 Norubonen, 5-ethylidene-2-Norubonen can include dichlorprop pentadiene, 1,4-hexadiene and the like.

  The copolymerization ratio of the unmodified ethylene copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms in (i) is preferably in the range of 40/60 to 99/1 (molar ratio), particularly 70/30 to 95/5 (molar ratio) is preferred.

  The copolymerization amount of the α-olefin having 3 or more carbon atoms in the unmodified ethylene copolymer comprising ethylene, the α-olefin having 3 or more carbon atoms and the non-conjugated diene in (ii) is preferably 5 to 80 mol%, In particular, 20 to 60 mol% is preferable, and the copolymerization amount of the non-conjugated diene is preferably 0.1 to 20 mol%, and particularly preferably 0.5 to 10 mol%.

  Specific examples of the unmodified ethylene copolymer include ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / 5-ethylidene-2- Examples thereof include norbornene copolymers. Among them, ethylene / propylene copolymers and ethylene / butene-1 copolymers that do not contain non-conjugated dienes are preferable because of their good heat resistance.

  The unsaturated carboxylic acid for obtaining a modified ethylene copolymer by graft reaction to the unmodified ethylene copolymer is preferably acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid. Citraconic acid, butenedicarboxylic acid, and the like. In addition, examples of derivatives thereof include alkyl esters, glycidyl esters, acid anhydrides, and imides. Among these, glycidyl esters, acid anhydrides, and imides are preferable.

  Preferred examples of the unsaturated carboxylic acid or derivative thereof include maleic acid, fumaric acid, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, diglycidyl citraconic acid, diglycidyl ester of butenedicarboxylic acid, anhydrous Mention may be made of maleic acid, itaconic anhydride, citraconic anhydride, maleic imide, itaconic imide, citraconic imide, etc., with glycidyl methacrylate, maleic anhydride, itaconic anhydride and maleic imide being particularly preferred. Two or more of these unsaturated epoxy monomers may be used in combination.

  The amount of the graft reaction of the unsaturated carboxylic acid or derivative thereof is preferably in the range of 0.01% by mass or more from the viewpoint of improving the mechanical properties, particularly the surface impact property, and 10% by mass or less from the point of heat resistance of the aromatic polyester. In particular, it is preferably 0.05 to 5% by mass.

  In addition, the graft reaction here means that an unsaturated carboxylic acid or a derivative thereof is chemically bonded to an unmodified ethylene copolymer.

  The modified ethylene copolymer is obtained by adding an unsaturated carboxylic acid or a derivative thereof to the unmodified ethylene copolymer and 0.001 to 0.1% by mass of an organic oxide based on the unmodified ethylene copolymer. It can be produced by melt-kneading at 150 to 300 ° C. As an apparatus in the case of melt mixing, a screw extruder, a Banbury mixer, etc. can be used.

  Organic peroxides that can be preferably used in this grafting reaction include tert-butyl cumyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butyl peroxide). Oxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, α, α′-di- (tert-butylperoxy) diisopropylbenzene, and the like.

  The resin composition comprising the components (A) and (B) described above has a melt viscosity of 50 to 50 at a shear rate of 1000 / second at a temperature 20 ° C. higher than the melting point of the liquid crystal resin of the component (A). 4000 Pa · s (preferably 60 to 3000 Pa · s, more preferably 60 to 1500 Pa · s), and a melt tension at a take-up speed of 15 m / min is 20 mN or more (preferably 50 mN or more, more preferably 100 mN or more).

  The resin composition used in the present invention may be composed of only the above-described liquid crystal resin, or may be composed of the above-described component (A) and component (B), but if necessary, crosslinked polyester, crosslinked polystyrene, thermoplastic resin Organic compounds such as inorganic fillers, hydrolysis inhibitors, antioxidants, heat stabilizers, light stabilizers, flame retardants, lubricants, antistatic agents, inorganic or organic colorants, rust preventives, crosslinking agents, foaming Various additives such as an agent, a fluorescent agent, a surface smoothing agent, a surface gloss improving agent, and a mold release improving agent such as a fluororesin can be blended. These additives can also be added during the manufacturing process or in subsequent processing steps.

  Examples of the thermoplastic resin include polyethylene, polypropylene, ethylene-α-olefin copolymer, polyethylene terephthalate, and the like. Further, as the thermoplastic resin, a thermoplastic resin modified by introducing a functional group into the molecular chain can also be used.

  Inorganic fillers include calcium carbonate, talc, clay, silica, magnesium carbonate, barium sulfate, titanium oxide, alumina, gypsum, glass flake, glass fiber, carbon fiber, alumina fiber, silica alumina fiber, aluminum borate whisker, titanium A potassium acid fiber etc. can be mentioned.

  The resin composition used in the present invention is produced by premixing the above components with a mixer such as a Henschel mixer, a tumbler blender, or a kneader, and then kneading with an extruder, or melt-kneading with a heating roll or a Banbury mixer. can do. In addition, since a resin composition hydrolyzes when heated in the presence of moisture, it is preferable to dry and dehydrate raw material components in advance.

<Method for producing tubular molded body>
Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an extrusion molding apparatus 10 for producing the tubular molded body of the present invention.

  First, the above solid granular resin composition is charged into the extruder 12 from the hopper 16. In the extruder 12, the resin composition is heated to a uniform molten state and supplied to the ring-shaped die 13. The additive used together with the resin component (for example, a fibrous filler such as glass fiber) can be introduced from the middle of the extruder 12.

  The ring-shaped die 13 is not particularly limited as long as the molten resin is uniformly developed from the extruder into a cylindrical shape, and a spider die or a spiral die can be used. In view of the thickness accuracy of the molded product, it is particularly preferable to use a spiral die, and preferably has a structure that allows air to flow from the inside of the die 13 into the molded product at the start of molding.

  The molten resin composition tube 30a continuously extruded from the ring-shaped die 13 is guided to the sizing device 11, and is stretched in the circumferential direction by being depressurized in the outer sizing 14 in the device, and simultaneously cooled and solidified. Is done.

  In the sizing apparatus 11, sizing can be applied to the inner and outer for cooling shaping, but as shown in the figure, it is preferable to apply outer sizing, and further, annular sizing for cooling shaping by negative pressure from the outside of the tubular molded body. Is preferred.

  Next, details of the sizing device 11 of the outer sizing method will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of the sizing apparatus of FIG.

  In the sizing device 11, the molten resin composition tube 30 a continuously extruded from the ring-shaped die 13 is guided from the inlet 21 into the tubular outer sizing 14.

  The outer sizing 14 can be adjusted in temperature from the outside when a cooling medium (cooling water or cooling gas) supplied from the cooling medium inlet 22 flows through the cylindrical cooling space 24 and is discharged from the cooling medium outlet 23. It is like that.

  The temperature control method can be air cooling, liquid cooling, or a combination thereof. If it is an air cooling method, a method of circulating air at room temperature, a method of circulating warm air or cold air can be applied, and if it is a liquid cooling method, cold water, room temperature water, hot water, polyethylene glycol, silicone oil, etc. can be used. A circulation method, a spray method, or the like can be applied.

  The outer sizing 14 can suck the molten resin composition tube 30a from the outside by reducing the pressure from a pressure reducing port 25 connected to a vacuum pump (not shown).

In the outer sizing 14, the inner diameter (D ₁ ) of the inlet 21 is substantially the same as the outer diameter of the die 13, but the inner diameter (D ₂ ) of the outlet 26 is the inner diameter of the inlet 21. It is larger than (D ₂ ) (D ₂ > D ₁ ). In FIG. 2, the inlet 21 and the portion excluding the inlet 27 and the portion 27 enlarged in a conical shape have the same dimensions as the inner diameter (D ₂ ) of the outlet 26.

The ratio of the inner diameter of the inlet 21 the inner diameter of _{(D 1)} and the inlet _{21 (D 2) (D 2} / D 1) is preferably 1.3 times or more, 1.5 times or more (e.g., 1.5 (5.0 times) is more preferable.

  The outer sizing 14 has a smooth inner surface 14a, and an average roughness (arithmetic average roughness; Ra) (JIS B0601-1994) is preferably 7.0 or less, more preferably 5.0 or less. preferable.

As shown in FIG. 1, the tube-shaped molded body 30 b that is retained by being cooled and solidified by the sizing device 11 is taken up by the take-up machine 15. At this time, the thickness ratio (t ₁ / t ₂ ) between the melted thickness (the thickness of the tube 30a) (t ₁ ) and the mold retaining thickness (the thickness of the tube 30b) (t ₂ ) at the time of manufacturing the tube is a liquid crystal resin. In order to obtain a tube-shaped molded body oriented in two directions, the range of the following formula (1) is preferably satisfied, and the formula (2) is more preferably satisfied. In consideration of molding stability, the molding condition range of the following formula (3) is preferable.

0.592 × BUR ² ≦ t ₁ / t ₂ ≦ 10 × BUR ² (1)
0.769 × BUR ² ≦ t ₁ / t ₂ ≦ 2 × BUR ² (2)
t ₁ : Thickness at melting (thickness of the tube 30a)
t ₂ : thickness at the time of mold holding (thickness of the tube 30b)
BUR: r ₂ / r ₁ (blow ratio)
(R ₁ : tube center diameter at melting, r ₂ : tube center diameter at mold retention)
v ₁ : Tube take-up speed at the time of melting v ₂ : Tube take-up speed at the time of mold holding DR take-off ratio: v ₂ / v ₁ (thickness ratio / BUR)
2.0 ≦ v ₂ / v ₁ (3)
The tube-shaped molded product obtained by the production method of the present invention has a molecular orientation degree of 80% or less in the longitudinal direction of the tube-shaped molded product in the crystal orientation analysis of wide-angle X-ray diffraction of the cut sample. Preferably it is 48 to 80%, more preferably 50 to 70%, still more preferably 50 to 55%.

By applying a known coextrusion method, the tubular molded body in the present invention,
One layer structure consisting only of liquid crystal resin,
A single-layer structure consisting only of a liquid crystal resin composition (including a liquid crystal resin and other resins),
Having a multilayer structure comprising a liquid crystal resin layer and a liquid crystal resin composition layer;
A multi-layer structure consisting of a liquid crystal resin layer and another thermoplastic resin layer,
Having a multilayer structure composed of a liquid crystal resin composition layer and another thermoplastic resin layer;
A multilayer structure comprising a liquid crystal resin layer, a liquid crystal resin composition layer, and another thermoplastic resin layer can be used.

  When the tube-shaped molded body has a multi-layer structure, the liquid crystal resin or liquid crystal resin composition layer is the inner layer and the other thermoplastic resin layer is the outer layer (protective layer). This is preferable because the tubular molded body can be prevented from being fibrillated by friction caused by contact between the surface and the outer surface of the tubular molded body.

  The surface of the tubular molded body of the present invention can be subjected to a surface treatment as necessary. As the surface treatment method, corona discharge treatment, plasma treatment, flame treatment, sputtering treatment, solvent treatment and the like can be applied.

  The tube-shaped molded body of the present invention can be used not only as a tube, but the tube-shaped molded body is cut inline or outline before and after the take-up machine, used as a sheet, or stretched into a sheet. By doing so, it can also be used as a stretched film.

  The stretching method is not particularly limited, but the simultaneous biaxial stretching method is preferable for stretching in a molten state. A screw system, a pantograph system, a linear motor drive system, and the like can be used as the film grip clip drive system, but the linear motor drive system is preferable because it can easily perform stretching control.

  When it is desired to change the stretching temperature condition in the longitudinal direction and / or the width direction, the film can be stretched in the longitudinal direction by a radiant heat heating method capable of heating the film in a non-contact manner, and stretched in the width direction by a hot air heating method. As a heat source for radiant heat heating, a hot wire heater or the like can be used, and it is preferable to stretch while heating between rolls having different peripheral speed differences. The film path at this time is preferably a system in which the film is stretched while traveling vertically from the lower roll to the upper roll, or a system in which the film is stretched while traveling vertically from the upper roll to the lower roll.

  The tubular molded body of the present invention has excellent mechanical strength, dimensional stability, and low gas permeability, and can be used for a gas transfer tube and a fuel tank tube for automobiles. Specifically, it can be widely used as various tubes for fuel, exhaust, intake-related tubes, pharmaceutical tubes for filling ointments, toothpastes, adhesives, leather creams, cosmetics, etc. in automobiles. it can.

(Evaluation methods)
[Melting point, glass transition temperature]
It measured on 20 degreeC / min temperature rising conditions with the differential scanning calorimeter (DSC7 by Perkin-Elmer Co.). Since the melting point Tm may be difficult to determine by melting peak in DSC if it is liquid crystalline, it is preferable to determine it together with the phase change under a crossed Nicol under a microscope.

[Liquid crystal]
Using a polarizing microscope manufactured by Olympus, a sample placed on a hot stage manufactured by Linkham was melted and observed at a magnification of 150 times in a nitrogen atmosphere. When it was inserted between crossed polarizers, light was transmitted, and when polarized light was transmitted even in the molten still liquid state, it was determined that the material was optically anisotropic.

[Melt viscosity]
The apparent melt viscosity at a temperature T1 (resin melting point + 20 ° C.) and a shear rate of 1000 / sec was measured according to ISO 11443 using a capillary rheometer (Capillograph 1B manufactured by Toyo Seiki: piston diameter 10 mm). For the measurement, an orifice having an inner diameter of 1 mm and a length of 20 mm was used.

[Melting tension]
Using the capillary rheometer, the molten polymer discharged from the orifice at a temperature of T1 (melting point of the resin + 20 ° C.) and a piston extrusion speed of 10 mm / min was obtained at 15 m / min using an orifice having an inner diameter of 1 mm and a length of 20 mm. The tension (mN) applied to the fiber when it was drawn into a fiber was measured.

[Tube formability]
During tube forming, it was determined whether or not the extrusion could be stably performed while adjusting the die temperature, the resin discharge amount, and the tube take-up speed.

[Tube appearance evaluation]
The tube appearance was evaluated based on the following criteria. Those having good appearance were determined to have good moldability.

  Good: Almost no flaws or defects are observed on the tube.

  Defect: The tube has flaws and defects.

[Evaluation of molecular orientation of tube]
The tube sample is cut open, and using a Rigaku wide-angle X-ray diffractometer RINT1400, X-rays are incident on the sample perpendicularly and a flat imaging plate photograph is taken. The orthorhombic (110) plane parallel to the molecular chain axis The azimuthal distribution was measured for the diffraction peaks from. Next, the azimuth angle β = 90 ° (φ = 0 °) is set as the azimuth with the maximum diffraction beam intensity, the β half-value width with respect to the intensity change from the baseline is determined, and the ratio to the total azimuth angle 360 ° is determined as the molecular orientation degree. (%). When the degree of molecular orientation is 80% or less, the anisotropy is small, meaning that the molecules are oriented in two directions.

Example 1
First, using a 40 mm single-screw extruder equipped with a spiral die, liquid crystal is horizontally discharged from an annular die having a cylinder setting temperature of 310 ° C., a screw rotation speed of 6 rpm, a die outer diameter of 5 mm, a die gap of 1 mm, and a die setting temperature of 300 ° C. A resin (Vectra A950 manufactured by Polyplastics Co., Ltd.) was melt extruded into a tube shape.

  Next, after melt extrusion, the outer diameter was expanded by vacuum pressure in the water tank while being led to outer sizing in the vacuum water tank and cooled, and then formed into a tubular molded body, and taken out at 5 m / min.

  The obtained tubular molded body had an outer diameter of 10 mm, a thickness of 0.120 mm, a degree of molecular orientation of 54%, and a good appearance.

Examples 2-4
In the same manner as in Example 1, the liquid crystal resin was melt-extruded into a tube shape, and led to the outer sizing in the vacuum water tank and cooled, and the outer diameter was expanded by the vacuum pressure in the water tank to form a tube shape. 7, 8, 9 m / The compact and the take-up speed were increased to obtain a molded body.

  The obtained tubular molded body had an outer diameter of 10 mm, thicknesses of 0.085, 0.075, and 0.065 mm, and molecular orientations of 58, 66, and 77%, respectively, and the appearance was good.

Comparative Example 1
In the same manner as in Example 1, the liquid crystal resin was melt extruded into a tube shape, led to the outer sizing in the vacuum water tank and cooled, and the outer diameter was expanded by the vacuum pressure in the water tank to form a tubular molded body at 10 m / min. I took it.

  The obtained tubular molded body had an outer diameter of 10 mm, a thickness of 0.060 mm, a molecular orientation degree of 81%, and a good appearance.

Comparative Example 2
The outlet diameter of the outer sizing was changed so that the outlet diameter (D ₂ ) / inlet diameter (D ₂ ) of the sizing was 1.2, the screw speed was increased to 8 rpm, and the liquid crystal resin was melt extruded into a tube shape as in Example 1. The outer diameter was expanded by the vacuum pressure in the water tank while being led to the outer sizing in the vacuum water tank and cooled, and formed into a tubular molded body, which was taken out at 5.5 m / min.

  The obtained tubular molded body had an outer diameter of 6 mm, a thickness of 0.250 mm, a degree of molecular orientation of 83%, and a good appearance.

Comparative Example 3
When molding was carried out with the take-up speed of Comparative Example 2 lowered to 3 m / min, the resin could not be molded in sizing.

Example 5
The outer sizing outlet diameter was changed so that the sizing outlet diameter (D ₂ ) / inlet diameter (D ₂ ) was 1.3. Similarly to Comparative Example 2, the liquid crystal resin was melt extruded into a tube shape, and the outer sizing in the vacuum water tank The outer diameter was expanded by vacuum pressure in the water tank while being cooled, and formed into a tube-shaped molded body, and taken up at 5 m / min.

  The obtained tubular molded body had an outer diameter of 7 mm, a thickness of 0.250 mm, a degree of molecular orientation of 72%, and a good appearance.

Example 6
Molding was carried out by lowering the take-up speed of Example 5 to 4 m / min. The obtained tubular molded body had an outer diameter of 7 mm, a thickness of 0.320 mm, a degree of molecular orientation of 70%, and a good appearance.

Comparative Example 4
When the molding speed of Example 6 was reduced by 3 m / min, the resin could not be molded during sizing.

Example 7
The outlet diameter of the outer sizing is changed, and the outlet diameter (D ₂ ) / inlet diameter (D ₂ ) of the sizing is set to 4. Otherwise, the liquid crystal resin is melt-extruded into a tube shape in the same manner as in Example 1 and is in a vacuum water tank. The outer diameter was expanded by vacuum pressure in the water tank while being led to outer sizing and cooled, and formed into a tubular molded body, which was taken up at 5 m / min.

  The obtained tubular molded body had an outer diameter of 20 mm, a thickness of 0.060 mm, a molecular orientation degree of 48%, and a good appearance.

The extrusion apparatus used with the manufacturing method of this invention. FIG. 2 is a longitudinal sectional view of the sizing device of FIG. 1.

Claims (6)

  A tube-shaped molded body obtained from a resin composition containing a liquid crystal resin, wherein a molecular orientation degree in the length direction of the tubular molded body is 80 in a crystal orientation analysis of wide-angle X-ray diffraction of a sample obtained by opening the tube-shaped molded body. % Of a tube-shaped molded product,   The tubular molded article according to claim 1, wherein the liquid crystal resin is a wholly aromatic polyester liquid crystal resin and / or a wholly aromatic polyester amide liquid crystal resin.   A resin composition containing a liquid crystal resin contains (A) 99-70% by mass of a wholly aromatic polyester and / or wholly aromatic polyester amide liquid crystal resin and (B) 1-30% by mass of a polymer containing an epoxy group. The melt viscosity of the resin composition at a shear rate of 1000 / second at a temperature 20 ° C. higher than the melting point of the liquid crystal resin is 50 to 4000 Pa · s, and the melt tension at a take-up speed of 15 m / min is 20 mN or more. The tubular molded body according to claim 1 or 2. It is a manufacturing method of the tube-shaped fabrication object in any one of Claims 1-3,
A resin composition containing a liquid crystal resin is melt-extruded from a ring-shaped die, and before the molten resin composition is solidified, the tube diameter is expanded to 1.3 to 5.0 times the die slip outer diameter, A method for producing a tubular molded body in which a liquid crystal resin contained in a resin composition is oriented in two directions.   The method for producing a tubular molded body according to claim 4, wherein after the molten resin composition is extruded from a ring-shaped die into a tube shape, the pressure is reduced from the outside of the tubular molded body by outer sizing and cooling is performed. The method for producing a tubular molded body according to claim 5, wherein the sizing device has a shape expanding from the inlet toward the outlet, and the ratio of the inlet diameter to the maximum diameter is 1.3 to 5.0 times.

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