JPH1180335A - Copolyester resin, copolyester resin composition and multilayered molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester-based resin excellent in gas barrier property; transparency and UV-cutting ability, and generating no toxic gas when burned, and to obtain a molded product using the above resin. SOLUTION: This copolyester resin has the following characteristics: the dicarboxylic acid component as a constituent of this resin is composed of 60-96 mol.% of isophthalic acid component, 2-25 mol.% of terephthalic acid component and 2-15 mol.% of 2,6naphthalenedicarboxylic acid component; wherein the sum of the isophthalic acid and terephthalic acid components accounts for 85-98 mol.% of the total dicarboxylic acid component; and the diol component as the other constituent of this resin is composed of 98.5-80 mol.% of ethylene glycol component and 1.5-20 mol% of diethylene glycol component; oxygen permeability coefficient is <=3.0 cc.mm/m<2> day.atm; and ultraviolet radiation absorption wavelength is <=330 nm. The second objective resin composition is obtained by including the above resin, and the third objective molded product is obtained by using the above composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a copolymerized polyester resin suitable for a molded article for packaging which is required to have properties such as gas barrier properties, transparency and UV cut properties, and a composition comprising the copolymerized polyester resin of the present invention. And a multilayer molded article using the polyester resin composition. More specifically, examples of the multilayer molded product include a blow molded product such as a stretch blow or a direct blow, and an extruded molded product such as a film or a sheet.

[0002]

2. Description of the Related Art Conventionally, polyethylene terephthalate resin (hereinafter referred to as PET) has excellent properties in mechanical strength, transparency and gas barrier properties. Widely used as molded products and cup-shaped containers. However, even in such a PET molded product, the gas barrier property against oxygen and the like is not sufficient, and when the storage is prolonged, when the container is small, and when a high gas barrier property is required, the commercial value of the contents is increased. Has the disadvantage of lowering In recent years,
When a container containing contents is displayed at a store, it is essential that the packaging material and the container are transparent in appearance, and prevention of deterioration and discoloration of the contents due to ultraviolet rays is also required. In recent years, in particular, the generation of harmful gases during incineration of molded articles using a vinyl chloride resin (hereinafter, PVC) resin has been greatly increased due to the problem of environmental waste. Therefore, it is excellent in gas barrier property, transparency, UV cut property, and PV
Polyester-based resins and molded articles that do not generate harmful gases during incineration such as C are desired. Known methods for remedying such disadvantages include a method using an ethylene vinyl alcohol polymer (hereinafter referred to as EVOH) having excellent gas barrier properties, and a method using polyethylene-2,6-naphthalene.
Using a resin (hereinafter referred to as PEN),
Methods using polyethylene isophthalate (hereinafter referred to as PEI) (JP-A-61-43561, JP-A-61-361)
No. 2,587,751). However, in such a molded article, when EVOH is used, the barrier property is reduced under high humidity, and when laminated with PET, kogation is generated in the molded article. It has disadvantages such as occurrence of a problem of separation of EVOH. Next, when PEN is used, since it is a typical crystalline polymer due to the molecular structure of PEN, and its melting temperature is as high as 270 ° C., the crystal nuclei can be completely formed unless the temperature at the time of melt extrusion is increased. Since it cannot be melted, the molded article is liable to be clouded, and the molding temperature is high, so that the amount of acetaldehyde generated during molding is increased. Further, when PEN and PET are melt-mixed, the compatibility with PET is poor, and if the molding temperature during melt extrusion is not raised to a high temperature, a pallet-like white turbidity occurs due to incompatibility, and PET is produced. It has the disadvantage that it is decomposed and its physical properties such as strength are remarkably reduced. Next, when PEI is used, PEI itself is brittle and has a low impact strength, so that it cannot be used practically. As described in JP-A-61-43561 and JP-A-258751, the inner layer is a mixture of PET and PEI. Can be considered. However, in such a method, since the compatibility between PET and PEI is poor, unless the melting temperature is set to a high temperature, a pallet-like white turbidity occurs during stretching during container molding. Further, PEI has the same ultraviolet absorption wavelength as PET and does not have UV-cutting properties, and has the drawback of lowering the commercial value of the contents due to ultraviolet rays, and improvement thereof has been desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copolymerized polyester resin suitable for a molded product for packaging which is required to have excellent properties such as gas barrier properties and transparency and a UV cut property. An object of the present invention is to provide a composition and a multilayer molded article suitable for a molded article for packaging having excellent gas barrier properties, transparency and UV cut properties using a polymerized polyester resin.

[0004]

DISCLOSURE OF THE INVENTION The present invention focuses on such problems, and as a result of intensive studies on a copolymerized polyester resin suitable for a molded article for packaging which does not have the above-mentioned drawbacks, has obtained gas barrier properties, transparency, and the like. The present inventors have found a copolymerized polyester resin which is excellent in UV cut properties and can improve the above-mentioned disadvantages, and reached the present invention. That is, the present invention provides a dicarboxylic acid component and
A copolymerized polyester resin comprising a dicarboxylic acid component and 60 to 96 mol% of an isophthalic acid component unit, 2 to 25 mol% of a terephthalic acid component unit, and 2,6-naphthalene. A dicarboxylic acid component unit of 2 to 15 mol%, a total amount of the isophthalic acid component unit and the terephthalic acid component unit in the dicarboxylic acid component is 85 to 98 mol%, and The ethylene glycol component unit is 98.5 to 80 mol%, the diethylene glycol component unit is 1.5 to 20 mol%, and the oxygen permeability coefficient is 3.0 cc · mm / m ^{2 based on the} total amount of the ethylene glycol component.・ Day ・ at
m is a copolymer polyester resin having a gas barrier property, a transparency and a UV cut property having an ultraviolet absorption wavelength of 330 nm or less.

Further, the resin composition of the present invention comprises a copolymerized polyester resin comprising a dicarboxylic acid component and a diol component, wherein the total amount of the dicarboxylic acid component constituting the copolymerized polyester resin is based on isophthalic acid component units. 60
９６96 mol%, terephthalic acid component unit 2-25 mol%, and 2,6-naphthalenedicadicarboxylic acid component unit 2-1
5 mol%, and the total amount of isophthalic acid component units and terephthalic acid component units in the dicarboxylic acid component is 85 to 98.
Mol%, and ethylene glycol is 9% based on the total amount of the diol component constituting the copolymerized polyester resin.
8.5-80 mol%, the diethylene glycol component unit is 1.5-20 mol%, and the oxygen permeability coefficient is 3.0 cc.
mm / m ²・ day ・ atm or less, UV absorption wavelength is 330nm
The polyester resin composition comprises 10 to 90 parts by weight of the following copolymerized polyester resin and 90 to 10 parts by weight of a polyethylene terephthalate-based resin containing ethylene terephthalate units as a main component.

Further, the multilayer molded article of the present invention comprises an intermediate layer and / or innermost layer comprising the polyester resin composition of the present invention and a polyethylene terephthalate-based resin containing ethylene terephthalate units as a main component. It has an outermost layer and / or an innermost layer, and has an oxygen permeability coefficient of 3.0 cc · mm / m ² · day
-A polyester multilayer molded product having characteristics of atm or less, light transmittance of 85% or more, and ultraviolet absorption wavelength of 330 nm or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymerized polyester resin of the present invention has an isophthalic acid component unit content of 60 to 96 based on the total amount of the dicarboxylic acid component constituting the copolymerized polyester resin.
Mol%, preferably 70 to 96 mol%, the terephthalic acid component unit is 2 to 25 mol%, preferably 2 to 15 mol%,
The 2,6-naphthalenedicarboxylic acid component unit contains 2 to 15 mol%, preferably 3 to 15 mol%, and the total amount of the isophthalic acid component unit and the terephthalic acid component unit in the constituent acid component is 85 to 98 mol. %, And the ethylene glycol component unit is 98.5 to 80 mol%, preferably 98 to 85 mol%, based on the total amount of the diol component constituting the copolymerized polyester resin, and the diethylene glycol component unit. Is 1.5 to 20 mol%, preferably 2 to 15 mol%. When the isophthalic acid component unit is less than 60 mol%, the effect of gas barrier property cannot be obtained, and when the terephthalic acid component unit is less than 2 mol%, the effect of improving the compatibility at the time of melt mixing with PET is lost. When the amount of 2,6-naphthalenedicarboxylic acid units is less than 2 mol%, the effect of the UV cut property is lost. When the diethylene glycol content is 1.5 mol% or less, the resulting multilayer molded article has poor impact resistance.

The copolymerized polyester resin of the present invention comprises, for example, isophthalic acid or its ester-forming derivative and terephthalic acid, or its ester-forming derivative and 2,6-naphthalenedicarboxylic acid or
The ester formation is induced, and as the glycol component, ethylene glycol or ethylene glycol and diethylene glycol are esterified or transesterified under appropriate reaction conditions in the presence of a catalyst, followed by polycondensation. Manufactured by

In the copolymerized polyester resin of the present invention, a part of the above-mentioned acid component may be added to a small amount of hexahydroterephthalic acid, hexahydroisophthalic acid, hydroxybenzoic acid, as long as the constituent component unit satisfies the above range. Acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, phenoxyethanedicarboxylic acid, 3,5-dicarboxybenzenesulfonic acid, oxalic acid, succinic acid, glutaric acid, sebacic acid, 2,2′- It may be replaced with one or more of oxydiacetic acid, glycolic acid and the like and ester-forming derivatives thereof.

In addition, a part of ethylene glycol is converted to a small amount of cyclohexanedimethanol, 1,2-propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene. It may be replaced with one or more of glycol, neopentylene glycol, polyalkylene glycol, for example, polyethylene glycol, polytetramethylene glycol, polypropylene glycol and the like. Furthermore, trimellitic acid and pyromellitic acid can be mentioned as other copolymerization components composed of polyfunctional compounds, for example, acid components, and glycerin and pentaerythritol can be mentioned as glycol components. The amount of the above-mentioned copolymer component to be used must be such that the copolymer polyester resin substantially maintains a linear shape.

[0011] The intrinsic viscosity (IV) of the copolymerized polyester resin is within a range in which melt extrusion can be performed, and from the mechanical properties of the obtained molded product, IV = 0.4 to 1.0 dl /.
g, preferably in the range of 0.6 to 0.9 dl / g. The copolyester resin of the present invention may be subjected to a heat treatment, if necessary, for the purpose of increasing the degree of polymerization or reducing acetaldehyde. This treatment may be carried out in the state of a composition with a polyethylene terephthalate resin.

In the present invention, the term "polyethylene terephthalate resin" means 100 units of ethylene terephthalate.
A thermoplastic polyester resin containing ~ 75 mol%,
Preferably, the ethylene terephthalate unit is from 100 to 8
It is a polyester resin containing 0 mol%, more preferably 100 to 85 mol% of ethylene terephthalate units.

The dicarboxylic acids used for the copolymerization include aromatic dicarboxylic acids such as isophthalic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and the like. Ester-forming derivatives of, adipic acid, sebacic acid,
Aliphatic dicarboxylic acids such as azelaic acid and succinic acid and their ester-forming derivatives, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and hexahydroterephthalic acid and their ester-forming derivatives, p-oxybenzoic acid, oxycaprone Oxy acids such as acids, and ester-forming derivatives thereof, and the like.

The glycol used for the copolymerization includes:
Aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, alicyclic glycols such as 1,4-cyclohexanedimethanol, bisphenol A, aromatic glycols such as an alkylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

Further, other copolymerizable components comprising a polyfunctional compound in the polyethylene terephthalate resin include trimellitic acid and pyromellitic acid as acid components, and glycerin as a glycol component. And pentaerythritol. The amount of the above-mentioned copolymer component to be used must be such that the polyethylene terephthalate resin maintains a substantially linear shape.

The above polyethylene terephthalate resin can be produced by a conventionally known production method. That is, terephthalic acid and ethylene glycol and / or
Alternatively, a direct esterification method of directly reacting the third component to remove water and esterifying the mixture followed by polycondensation under reduced pressure, or dimethyl terephthalate and ethylene glycol and / or
Alternatively, it is produced by a transesterification method in which methyl alcohol is distilled off by reacting a third component and transesterification is carried out, followed by polycondensation under reduced pressure. Solid state polymerization may be performed to further increase the intrinsic viscosity and decrease the acetaldehyde content.

The intrinsic viscosity of the polyethylene terephthalate resin used in the present invention is 0.55 to 1.2 dl / g,
Preferably, it is in the range of 0.60 to 1.0 dl / g, more preferably 0.65 to 0.9 dl / g.

It is preferable to use a catalyst and a stabilizer during the above-mentioned transesterification reaction, esterification reaction and polycondensation reaction. The copolymerized polyester resin and polyethylene terephthalate-based resin of the present invention include a heat stabilizer, a thermal oxidation stabilizer, an antistatic agent, a weather resistance stabilizer, a lubricant, a pigment, a dye, a pigment dispersant, and the like. Can be added in a range that does not impair the purpose.

The polyester resin composition of the present invention comprises 90 to 10% by weight of the polyethylene terephthalate resin.
And 10 to 90% by weight of the above-mentioned copolyester resin, preferably 90 to 3% by weight of polyethylene terephthalate resin.
It is composed of 0% by weight and 10 to 70% by weight of a copolyester resin. 10% by weight of copolyester resin
In the following cases, the barrier property is not improved, and when it is 90% by weight or more, the heat resistance, mechanical strength, etc. of the molded body are reduced, which is problematic.

In order to obtain the polyester resin composition of the present invention, various known methods which can uniformly mix the polyethylene terephthalate resin and the copolymerized polyester resin can be used. And a method in which both resins mixed by such a method are melt-kneaded and granulated by a single-screw extruder, a twin-screw extruder, a vent-type extruder, or the like. Things are also possible.

The polyester resin composition of the present invention includes a thermoplastic resin such as a polyamide resin and a polyolefin resin, a heat stabilizer, a thermooxidative stabilizer, an antistatic agent, a weather resistance stabilizer, a lubricant, a pigment, a dye, In addition to adding a transition metal salt or a pigment dispersant, etc., to each resin as a component of the composition, it can be added within a range that does not impair the object of the present invention.

The multilayer molded article of the present invention comprises an intermediate layer comprising a polyester resin composition containing 10 to 90 parts by weight of the above specific polyester resin and 90 to 10 parts by weight of a polyethylene terephthalate resin. It is a multilayer molded article having an innermost layer and an outermost layer and / or an innermost layer made of a polyethylene terephthalate resin, and a thickness ratio of the outermost layer, the intermediate layer and the innermost layer is from 0.5 to 3: 4 to 9: 0.5-3
Is preferred.

The multilayer molded article of the present invention can be manufactured by a conventionally known method such as multilayer extrusion molding, multilayer injection molding, and multilayer direct blow molding. The obtained multilayer sheet is conventionally known as a uniaxial stretching method, a sequential biaxial stretching method,
It can be stretched by a simultaneous biaxial stretching method or the like to obtain a multilayer stretch molded product such as a multilayer stretch film. It is also possible to form the multilayer sheet into a cup-shaped product or a tray-shaped product by a pressure forming method, a vacuum forming method or the like. Further, a multilayer stretched hollow molded article can be obtained by stretch blow molding a preform which is a multilayer molded article, but is not particularly limited thereto.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. First, the main methods of measuring physical properties are as follows. (1) Intrinsic viscosity (IV) A mixed solvent of phenol / tetrachloroethane at a temperature of 30
Measured at ° C. (2) Oxygen permeability OX-TRAN100 type oxygen permeability meter (MOCON
Was measured at a temperature of 25 ° C. and a humidity of 50%.

(3) UV cut properties Measured by a spectrophotometer UV-210A (manufactured by Shimadzu Corporation). The ultraviolet absorption wavelength of the copolymerized polyester resin of the present invention was measured with a sheet of 300 μm. (4) Impact resistance Measured at room temperature with a DuPont type falling weight impact tester at n = 5.

The used PET resin and copolymerized polyester resin are as follows. (A) PET resin PET resin with IV = 0.75 manufactured by Toyobo Co., Ltd. (a-1) (b) Copolyester resin The copolyester resin of the present invention comprises dimethyl isophthalate, dimethyl terephthalate and 2,6- An initial condensate is produced by a normal transesterification method in which a transesterification reaction between dimethyl naphthalenedicarboxylate and ethylene glycol and / or diethylene glycol in the presence of a catalyst, and the initial condensate is subjected to a conventional polycondensation method. And obtained by polycondensation. Table 1 shows the composition of the obtained copolyester resin. The IV of each resin is approximately 0.80.

Examples 1 to 3 and Comparative Example 1 An unstretched sheet having a thickness of 0.1 mm was obtained using a press sheet molding machine manufactured by SHINTO using each of the above resins. Table 1 shows the evaluation results of the oxygen transmission coefficient and ultraviolet absorption wavelength of the sheet.

[0028]

[Table 1]

As apparent from Table 1, the copolymerized polyester resin of the present invention exhibits excellent gas barrier properties and UV cut properties, and also has good transparency.

Example 4 20 parts by weight of the copolymerized polyester resin (a-1) of Example 1 and 80 parts by weight of a PET resin were dry-blended and subjected to SHI.
An unstretched sheet having a thickness of 0.1 mm was obtained with a press sheet molding machine manufactured by NTO. Table 2 shows the evaluation results of the oxygen transmission coefficient and ultraviolet absorption wavelength of the sheet.

Examples 5 to 6 Unstretched sheets were prepared in the same manner as in Example 4, and the characteristic values were evaluated. Table 2 shows the results.

[0032]

[Table 2]

Example 7 and Comparative Example 3 Using an ASB-50TH multilayer blow molding machine manufactured by Nissei ASB, the thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1, and the copolymerized polyester resin was used. (B-2) A composition comprising 60 parts by weight and 40 parts by weight of PET resin is used as an intermediate layer to form a PE.
A multilayer stretch blow-molded product (capacity: 500 cc) having a T resin as an outer layer and an inner layer was obtained. The multilayer stretch blow-molded product had an oxygen transmission coefficient of 1.5 cc · mm / m ² · day · atm and an ultraviolet absorption wavelength of 356 nm or less. The molded product of the same capacity manufactured by using the PET resin alone as Comparative Example 3 had an oxygen transmission coefficient of 4.1 cc · mm / m ² · day · atm and an ultraviolet absorption wavelength of 310 nm.

Example 8 The thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1 using a homemade direct blow molding machine, and 60 parts by weight of the copolymer polyester resin (b-2) and 40 parts by weight of the PET resin were used. A multilayer direct blow-molded product (capacity: 270 cc) having the composition from the part as the intermediate layer and the PET resin as the outer layer and the inner layer was obtained. The oxygen permeability coefficient of the container is 1.5 cc · mm / m ² · day ·
Atm and ultraviolet absorption wavelength were 355 nm or less.

Example 9 The thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1 using a homemade multilayer sheet molding machine, and the copolymerized polyester resin (b
-2) A multilayer sheet molded product (thickness: 0.3 mm) having a composition comprising 60 parts by weight and 40 parts by weight of PET resin as an intermediate layer and an outer layer and an inner layer of PET resin was obtained. This multilayer sheet was stretched 3 × 3 times with a film stretching machine manufactured by Toyo Seiki to obtain a film. This multilayer stretched film has an oxygen permeability coefficient of 1.3 cc · mm / m ² · day · atm or less, an ultraviolet absorption wavelength of 355 nm or less, and excellent gas barrier properties.
V-cut property was shown.

Example 10 and Comparative Example 4 The copolymerized polyester resin (b-2) of Example 2 and PE
The thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1 using a homemade multilayer sheeting machine using T resin, and 40 parts by weight of the copolymerized polyester resin (b-2) and 60 parts by weight of the PET resin. A three-layer sheet having a thickness of 1.0 mm was obtained using the composition consisting of an intermediate layer and PET resin as an outer layer and an inner layer. Also,
For comparison, a three-layer sheet similar to that of Example 8 was obtained using the copolymerized polyester resin (b-4) (Comparative Example 4).
The impact resistance of these sheets at room temperature was measured by a DuPont type falling weight impact tester. Although the sheet of Example 8 did not crack even when the weight was dropped from a height of 3 m, the sheet of Comparative Example 4 all cracked. The multilayer molded article using the copolymerized polyester resin composition of the present invention exhibited excellent impact strength.

[0037]

The copolymerized polyester resin of the present invention is excellent in transparency, gas barrier properties and ultraviolet absorption. Also, the resin composition comprising the copolymerized polyester resin and the PET resin of the present invention is similarly excellent in transparency, gas barrier properties, and ultraviolet absorption. Therefore, it is useful as a packaging material and can be widely used for containers, sheets, films and the like. Further, the multilayer molded article of the present invention has excellent transparency, gas barrier properties, ultraviolet absorption and impact resistance.

Claims (3)

[Claims] 1. A copolymerized polyester resin comprising a dicarboxylic acid component and a diol component, wherein, based on the total amount of the dicarboxylic acid component constituting the copolymerized polyester resin,
An isophthalic acid component unit in a dicarboxylic acid component, comprising 60 to 96 mol% of an isophthalic acid component unit, 2 to 25 mol% of a terephthalic acid component unit, and 2 to 15 mol% of a 2,6-naphthalenedicarboxylic acid component unit; The total amount of the component units is 85 to 98 mol%, and the ethylene glycol component unit is 98.5 to 80 mol% based on the total amount of the diol component constituting the copolymerized polyester resin, and diethylene glycol is used. A copolymerized polyester resin having a component unit of 1.5 to 20 mol%, an oxygen permeability coefficient of 3.0 cc · mm / m ² · day · atm or less, and an ultraviolet absorption wavelength of 330 nm or less. 2. A copolymerized polyester resin comprising a dicarboxylic acid component and a diol component, wherein the total amount of the dicarboxylic acid component constituting the copolymerized polyester resin is
An isophthalic acid component unit in a dicarboxylic acid component, comprising 60 to 96 mol% of an isophthalic acid component unit, 2 to 25 mol% of a terephthalic acid component unit, and 2 to 15 mol% of a 2,6-naphthalenedicarboxylic acid component unit; The total amount of the component units is 85 to 98 mol%, and the ethylene glycol component unit is 98.5 to 80 mol% based on the total amount of the diol component constituting the copolymerized polyester resin, and diethylene glycol is used. 10 to 90 parts by weight of a copolymerized polyester resin having a component unit of 1.5 to 20 mol%, an oxygen permeability coefficient of 3.0 cc · mm / m ² · day · atm or less, and an ultraviolet absorption wavelength of 330 nm or less, and ethylene Telephthale
A polyester resin composition comprising 90 to 10 parts by weight of a polyethylene terephthalate-based resin having a main unit as a main component. 3. An intermediate layer and / or an innermost layer comprising the polyester resin composition according to claim 2, and an outermost layer and / or an innermost layer comprising a polyethylene terephthalate-based resin having an ethylene terephthalate unit as a main component. A multilayer molded article having the following characteristics: an oxygen permeability coefficient of 3.0 cc · mm / m ² · day · atm or less, a light transmittance of 85% or more, and an ultraviolet absorption wavelength of 330 nm or less.