JPH07119100B2 - Polyester molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminated polyester molded product obtained by laminating a specific liquid crystal polyester (B) layer on a polyester (A) layer, and more specifically, The present invention relates to a polyester molded product having excellent gas barrier properties, adhesiveness, and dimensional stability.

[Prior Art] It is well known that liquid crystal polyesters have excellent mechanical properties, heat resistance, chemical resistance, etc. in JP-A-51-8395.

[Problems to be Solved by the Invention] However, liquid crystal polyester has poor fluidity and moldability even when melted, and a thin film having a uniform thickness cannot be obtained. Further, it has the drawback that it cannot be used as a blending material or a laminating material because it has no compatibility or adhesiveness with ordinary polyesters such as polyethylene terephthalate.

Therefore, the present invention provides a thin liquid crystal by modifying the liquid crystal polyester to give not only fluidity at the time of melting and moldability but also adhesiveness and compatibility with a general-purpose polyester such as polyethylene terephthalate. An object of the present invention is to obtain a laminated polyester molded product in which a polyester layer is laminated and which is excellent in gas barrier properties and the like.

[Means for Solving the Problems] Therefore, in order to achieve the above object, the present inventors have the following configuration, that is, a liquid crystal containing a monomer having a sulfonate on at least one surface of the polyester (A) layer. It has been found that a polyester molded body in which a polyester (B) layer is laminated may be used.

The liquid crystalline polyester (B) of the present invention is a polyester that exhibits optical anisotropy even when flowing, and there are a thermotropic type and a rheotropic type. In the present invention, the thermotropic type is used. Cheap. The preferred structure comprises a structural unit selected from the following structural units (I), (II), (III), (IV) and (V), wherein the structural unit (I) is [(I) + (II) + (III)] 20-90 mol%
And the structural unit (V) is [(IV) + (V)] 1-10
The structural unit [(IV) + (V)] accounts for 0 mol% and is substantially equal to the number of moles of the structural unit [(II) + (III)].

_{O-R 1 -O ...... (II} ) O-CH 2 CH 2 -O ...... (III) The structural unit (I) is (a) a structural unit of polyester produced from p-hydroxybenzoic acid, and the structural unit (II) is (b) 4,4'-dihydroxybiphenyl, hydroquinone, 2,6-dihydroxynaphthalene. , 2,7-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl ether, t-butyl hydroquinone, 3,3 ', 5,5'-
A structural unit formed from an aromatic dihydroxy compound selected from tetramethyl-4,4'-dihydroxybiphenyl and phenylhydroquinone, a structural unit (III) is a structural unit formed from ethylene glycol, a structural unit (I
V) is (c) terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4 '
A structural unit formed from an aromatic dicarboxylic acid selected from dicarboxylic acid and 4,4′-diphenyletherdicarboxylic acid, structural unit (V) is (d) a sulfonic acid represented by an alkali metal salt of 5-sulfoisophthalic acid 1 shows a structural unit formed from the salt SO ₃ M.

Further, particularly preferable as the liquid crystal polyester (B) of the present invention are the above structural units (I), (II), (III),
Structural unit consisting of (IV) and (V) [(I) + (I
I)] occupies 35 mol% or more of the structural unit [(I) + (II) + (III)], and the structural unit [(IV) + (V)] is substantially the structural unit [(II) + ( III)]. In this case, the structural unit [(I) + (II)] is more preferably 40 to 9 of the structural unit [(I) + (II) + (III)].
It is 5 mol%, particularly preferably 70 to 85 mol%. Also,
The molar ratio of structural unit (I) / (II) is preferably 75/25 to 95/5. Further, the structural unit (III) is a structural unit [(I) + (I
60 to 5 mol% of (I) + (III)] is preferable, and 30 to 15 mol% is particularly preferable. Of these, R ₁ in the formula is But for R ₂ Is most preferred. In this case, the structural unit (V) is 1 to 100 mol% of [(IV) + (V)], preferably 5 to 5%.
It is 0 mol%, more preferably 7 to 30 mol%. However, M in the formula represents an alkali metal such as Na, Li, K, Cs, or Rb. If this ratio is less than 1 mol%, the effect of the present invention cannot be achieved, and if it exceeds 70 mol%, mechanical properties, gas barrier properties, thermal properties, etc. are greatly deteriorated, which is not preferable.

The method for producing the liquid crystal polyester (B) of the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

When the structural unit (III) is not included, the following (1)
To (4), and when the structural unit (III) is included, the production method of (5) is preferably mentioned.

(1) Deacylation of aromatic dihydroxy compounds such as p-acetoxybenzoic acid, 4,4'-diacetoxybiphenyl, and paraacetoxybenzene with 5-sulfoisophthalic acid monosodium salt and aromatic dicarboxylic acids such as terephthalic acid. A method for producing by acetic acid polycondensation reaction.

(2) Aromatic dihydroxy compounds such as p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl and hydroquinone, and 5-sulfoisophthalic acid monosodium salt, aromatic dicarboxylic acids such as terephthalic acid are reacted with acetic anhydride, A method of producing by a deacetic acid polycondensation reaction after acetylating a phenolic hydroxyl group.

(3) Phenyl ester of p-hydroxybenzoic acid,
A method for producing from an aromatic dihydroxy compound such as 4,4'-dihydroxybiphenyl and hydroquinone, a monosodium salt of 5-sulfoisophthalic acid, a diphenyl ester of an aromatic dicarboxylic acid such as terephthalic acid by a dephenol polycondensation reaction.

(4) p-Hydroxybenzoic acid, 5-sulfoisophthalic acid monosodium salt, aromatic dicarboxylic acids such as terephthalic acid are reacted with desired amounts of diphenyl carbonate to form diphenyl esters, and then 4,4'-
A method for producing by a dephenol polycondensation reaction by adding an aromatic dihydroxy compound such as dihydroxybiphenyl or hydroquinone.

(5) In the presence of a polymer or oligomer composed of an aromatic dicarboxylic acid such as 5-sulfoisophthalic acid monosodium salt or terephthalic acid and ethylene glycol, or a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid, (1) or The method of manufacturing by the method of (2).

Typical catalysts used in the polycondensation reaction are stannous acetate, tetrabutyl titanate, potassium acetate, antimony trioxide, magnesium, sodium acetate, and other metal compounds, and are particularly effective during dephenol polycondensation. is there.

The liquid crystal polyester (B) of the present invention has a melt viscosity of 10 to
15,000 poise is preferable, and 20 to 5,000 poise is particularly preferable.

The melt viscosity is a value measured by a Koka flow tester at a liquid crystal starting temperature + 40 ° C and a shear rate of 1,000 (1 / sec).

On the other hand, the liquid crystal polyester (B) of the present invention has an inherent viscosity of 0.
It can be measured in pentafluorophenol at a concentration of 1g / dl and 60 ° C, 0.3 to 15dl / g is preferable, and structural unit (III)
When it contains, 0.3 to 3.0 dl / g is particularly preferable.

In addition, when polycondensing the liquid crystal polyester (B) of the present invention, in addition to the components constituting the structural units (I) to (V),
Aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid and 2,2′-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanedioic acid, and fats such as hexahydroterephthalic acid Cyclic dicarboxylic acid, chlorohydroquinone, methylhydroquinone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, etc. Aromatic diols of 1,4-
Butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, polyethylene glycol and other aliphatic, alicyclic diols and m-hydroxybenzoic acid, 2 Aromatic hydroxycarboxylic acids such as 6,6-hydroxynaphthoic acid can be further copolymerized in a small proportion within a range not impairing the object of the present invention.

The liquid crystal polyester (B) of the present invention thus obtained can obtain a high degree of polymerization polymer only by melt polymerization, and has good optical anisotropy,
It exhibits mechanical properties, gas barrier properties, heat resistance, and excellent flowability during melting, making it suitable for ordinary melt-molded products such as extrusion molding with polyester (A), injection molding, compression molding, and blow molding. Can be served, fiber,
It is possible to perform processing such as molding and stretching on films, three-dimensional molded products, containers, hoses, etc. In the case of the present invention,
In particular, when formed into a film, it can be biaxially stretched, and the effect becomes remarkable. Further, it is possible to impart functions such as affinity and adhesiveness with other thermoplastic polymers without impairing the above characteristics.

The liquid crystal polyester (B) of the present invention shows excellent affinity when blended with other thermoplastic polymers. Preferred thermoplastic polymers include polyamide, polyoxymethylene,
Examples thereof include polycarbonate, polyarylene oxide, polyalkylene terephthalate, polyarylene sulfide, polysulfone, polyether sulfone, amorphous polyarylate and polyether ether ketone.

With respect to the liquid crystal polyester (B) of the present invention, a reinforcing agent such as glass fiber, carbon fiber and asbestos, a filler, a lubricant, a release agent, a nucleating agent, a plasticizer, a flame retardant, a heat stabilizer, an ultraviolet absorber, Pigments, dyes, etc. may be added as needed to impart desired properties.

The liquid crystal polyester (B) of the present invention may be blended with other thermoplastic polymers, fillers, additives, reinforcing agents, etc., but a screw extruder or the like is preferably used for simplicity.

In addition, the normal polyester (A) which does not show optical anisotropy when melted in the polyester used for the base film,
For example, the constitutional units (I) and (II) are not included, and (III) and
Typical examples are polyesters composed of (IV) and (V), such as polyethylene terephthalate, polyethylene naphthalate, polycyclohexylene dimethylene terephthalate, and polybutylene terephthalate.

Further, as a method of laminating the liquid crystal polyester (B) layer containing a monomer having a sulfonate on the polyester (A) layer, any of the following methods may be used.

A so-called coextrusion method in which the polyester (A) and the liquid crystal polyester (B) are laminated in a molten state.

A so-called extrusion laminating method in which a molten liquid crystal polyester (B) is laminated on a cast or stretched polyester (A) molded body. If necessary, stretching and heat treatment may be performed after the lamination.

Since the liquid crystalline polyester (B) of the present invention has an excellent affinity for water, a method of coating an aqueous solution or a water dispersion on a polyester (A) molded article and drying. This may also be stretched or heat-treated after coating, if necessary.

Since the liquid crystal polyester (B) contains a sulfonate when the polyester molded body is stretched and oriented,
When stretched in a water-containing state, even a thin film having a thickness of less than 5 μm can be stretched with low tension and uniform high magnification. If the liquid crystal polyester (B) layer is dehydrated and dried after stretching, excellent properties can be exhibited because the liquid crystal polymer is strongly aligned. The stretching does not necessarily have to be carried out in the water-containing state, but the water-containing stretching is more advantageous in view of stability of the stretching, higher magnification, thinning, and the like.

The degree of orientation of the liquid crystal polyester (B) layer can be judged by the absolute value of the refractive index of the surface. That is, it can be judged by the difference from the refractive index of the completely non-oriented amorphous polymer. The measurement can be usually performed using an Atsube refractometer or an X-ray diffraction method. The orientation direction can be judged by the magnitude of the refractive index in the longitudinal direction and the width direction, and the orientation direction has the larger refractive index. In the case of the present invention, it is more preferable not only when it is oriented in the longitudinal direction but also in the width direction when it is oriented biaxially, because excellent properties such as gas barrier properties and mechanical properties can be imparted.

The molded body thus obtained can be improved in gas barrier property, dimensional stability and strength by heat treatment, and in some cases also in elastic modulus.

This heat treatment can be performed by heat-treating the molded body in an inert atmosphere (for example, nitrogen, argon, helium, or water vapor) or an oxygen-containing atmosphere (for example, air) at a temperature below the melting point of the polymer. This heat treatment may be performed under tension or relaxation, and can be performed for several seconds to several days.

[Effects of the Present Invention] Since the liquid crystal polyester (B) layer having a sulfonate is laminated on the polyester (A), the following wonderful effects are recognized.

1.Since extrusion properties and flow properties are similar to ordinary polyester, coextrusion with other polymers, extrusion lamination, coating, etc. can be easily performed.

2.Because it has excellent water absorption, it can be stretched with water.
Stable stretching becomes possible. If dehydrated after stretching, it exhibits excellent gas barrier properties, mechanical properties, dimensional stability, and easy adhesion.

3.Because it has excellent adhesiveness, it is easy to laminate and
The strong adhesion prevents delamination.

4. It shows excellent gas barrier properties, mechanical properties, dimensional stability, etc. even when the polyester (B) layer is thinner than 5 μm.

[Examples] The present invention will be further described below with reference to Examples.

Example 1 In a reaction vessel equipped with a stirrer and a distillation tube, 828.7 g (6.0 mol) of p-hydroxybenzoic acid, 148.9 g (0.8 mol) of 4,4'-dihydroxybiphenyl and 853.4 g (8.36 mol) of acetic anhydride, terephthalate Acid 66.5 g (0.4 mol), 5-sulfoisophthalic acid monosodium salt 107.2 g (0.4 mol) and polyethylene terephthalate 230.6 g with an intrinsic viscosity of about 0.6
(1.2 mol) was charged, and deacetic acid polymerization was performed under the following conditions.

First, in a nitrogen gas atmosphere at 100-250 ° C for 5 hours, 250-3
After reacting at 00 ℃ for 1.5 hours, at 300 ℃ for 1 hour, 0.5mmHg
When the pressure was reduced to 2, and the reaction was further continued for 2.25 hours to complete the polycondensation, almost the theoretical amount of acetic acid was distilled off to obtain a polymer.

The theoretical structural formula of this polymer is as follows, and its elemental analysis results showed good agreement with theoretical values.

In addition, the liquid crystal polyester (B) was placed on a sample stand of a polarization microscope, and the temperature was raised to confirm the optical anisotropy.
The liquid crystal starting temperature was 274 ° C., which showed good optical anisotropy.

The logarithmic viscosity (60 ° C. in pentafluorophenol) of this polymer (B) was 1.86 dl / g, and the melt viscosity was shear rate 1,
At 000 (1 / sec), the fluidity was 1800 poise, which was extremely good.

As the polyester (A), polyethylene terephthalate (intrinsic viscosity in o-chlorophenol of 0.63) was used.

Each of the polyester (A) and the liquid crystal polyester (B) was melted at 290 ° C., then laminated in two layers in a die and coextruded to obtain a two-layer laminated film at a speed of 35 m / min. The laminated film thus obtained was stretched 3 times in the longitudinal direction in a steam oven filled with saturated steam at 95 ° C. Subsequently, the film was stretched 3.5 times in a width-direction stretching tenter heated to 105 ° C., and further heat-set for 7 seconds at 215 ° C. while relaxing in the width direction by 3%.

Extrusion and stretching could be performed very smoothly, there was no film breakage during stretching, and the thickness of the obtained film was uniform.

The characteristics of the film thus obtained are shown.

Comparative Example 1 p-Hydroxybenzoic acid was added to the same reaction vessel as in Example 1.
8.7 g (6.0 mol), 4,4'-dihydroxybiphenyl 149.
Charge 0 g (0.80 mol), acetic anhydride 853.5 g (8.36 mol), terephthalic acid 132,9 g (0.80 mol), and polyethylene terephthalate 230.6 g (1.20 mol) with an intrinsic viscosity of about 0.6 under the same conditions as in Example 1. Polymerization gave a polymer having the following theoretical structural formula.

The liquid crystal onset temperature of this polymer was 275 ° C. This polymer was coextruded with polyester (A) in the same manner as in Example 1.

However, the fluidity of the polymer was poor, and lamination with a uniform thickness could not be achieved. Of course, this was biaxially stretched, but it was broken and a film having a uniform thickness could not be obtained.

Example 2 The liquid crystal polyester (B) used in Example 1 was dispersed in water to obtain a coating solution by a conventional method.

Next, polyethylene terephthalate, which is the polyester (A) used in Example 1, was melted at 290 ° C. by a conventional method, a constant amount was supplied by a gear pump, and the molten sheet was discharged from the die. 20 ° C while applying electrostatic charge to the sheet
The sheet was cooled by closely contacting it with a cooling drum kept in the form of a cast sheet. The sheet was stretched 4 times in the longitudinal direction on a roll heated to 95 ° C, the stretched film was coated with a water-dispersed coating liquid of liquid crystalline polyester (B), and then the film was stretched in the width direction. It is supplied to a machine (tenter), preheated at 90 ° C, dehydrated, and then stretched 4 times in the transverse direction at 105 ° C, and further heat treated at 215 ° C for 7 seconds to form a two-layer coating film (coating layer 1 μm, base 11 μm).
m) was obtained.

The oxygen permeability of the film thus obtained is 0.8 (cc / m ² ·
It can be seen that the excellent gas barrier property is shown as (day / sheet). Of course, there was no problem in coating suitability and transverse stretchability.

Claims (5)

[Claims] 1. A polyester molded article comprising a polyester (A) layer and a liquid crystal polyester (B) layer containing a monomer having a sulfonate, which is laminated on at least one side of the polyester (A) layer. 2. The polyester molded article according to claim 1, wherein the sulfonate is selected from 5-sulfoisophthalate and its derivatives. 3. The polyester molded product according to claim 1, wherein the polyester molded product is a film. 4. The polyester molded article according to any one of claims 1 to 3, wherein the liquid crystal polyester (B) is biaxially oriented. 5. The liquid crystal polyester (B) layer has a thickness of 5 μm.
It is less than m, The polyester molded object in any one of Claims (1)-(4) characterized by the above-mentioned.