JPH0236257A - Polyester resin composition and drawn material thereof - Google Patents

Abstract

PURPOSE:To obtain a composition having excellent gas barrier properties, transparency and melt molding properties comprising a polyester prepared from a diol component consisting essentially of ethylene glycol as a main component and a small amount of diethylene glycol and terephthalic acid (derivative). CONSTITUTION:(A) A diol component consisting of ethylene glycol as a main component and >=4mol%, preferably 4-10mol% diethylene glycol is polymerized with (B) a dicarboxylic acid component consisting of terephthalic acid (ester- forming derivative) as a main component in the presence of a catalyst (e.g., antimony trioxide or germanium dioxide), heat stabilizer, light stabilizer, etc., to give a polyester resin composition having 0.5-2dl/g, preferably 0.7-1.5dl/g intrinsic viscosity. A hollow molded article prepared by drawing and molding the composition wherein a thin part of barrel is drawn at least in one direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyester resin composition that has excellent gas barrier properties and i3 brightness and is suitable for packaging, and a stretched product thereof.

(Prior art and problems to be solved by the invention) Polyethylene terephthalate resin (hereinafter abbreviated as PET)
Thermoplastic polyester resin, represented by It is processed into films, sheets, etc., and is widely used as packaging material. Especially in recent years, with the improvement of blow molding technology and two-wheel stretch blowing technology,
Its use as a hollow container is also remarkable.

However, containers made of thermoplastic polyester resin whose main component is PUT have the disadvantage of insufficient gas barrier properties, and in the case of containers for beer and carbonated drinks, which require particularly strict gas barrier properties, it is necessary to increase gas barrier properties. Conventionally used methods for this purpose include increasing the wall thickness and using ethylene vinyl alcohol copolymers, polyamides, vinylidene chloride polymers, acrylonitrile resins, etc.
There is a method of molding IET in two layers. The method of increasing the wall thickness of iii+a increases the basis weight, and the latter method of two-layer molding makes it difficult to regenerate the resin, resulting in large waste of resin and increasing the overall material cost. There is a problem that a layer molding machine is required.

In JP-A No. 50-45895, there are mentioned those having an ether bond and having improved gas barrier properties,
It copolymerizes poly(alkylene oxide) glycol with a number average molecular weight of 600 to 6,000, and has poor heat resistance.

Also, what is shown in Japanese Patent Application Laid-open No. 61-241349 is OCHzCI (CH20R'hi).

○I ((R': divalent aromatic hydrocarbon group) It is characterized in that it contains a polyhydroxy polyether as a component unit, and particularly contains a hydroquine group.

The object of the present invention is to develop a polyester resin that has excellent gas barrier properties and melt moldability, and exhibits excellent performance as a stretch blow molded container and film.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object.

That is, in a polyester produced from a diol component unit containing ethylene glycol as a main component and a dicarboxylic acid component unit containing terephthalic acid or its ester-forming derivative as a main component, diethylene glycol accounts for 4 mol% or more as the diol component unit. This is a polyester resin composition characterized by the following.

Diethylene glycol content in preferred polymers [1
is 4 mol% or more and 10 mol% or less.

The dicarboxylic acid component units used in the resin composition of the present invention are mainly composed of terephthalic acid component units, and other dicarboxylic acid component units include isophthalic acid, naphthalene dicarboxylic acid, phthalic acid, cyclohexanedicarboxylic acid, sebacic acid, and azelain. Examples include aromatic ring group and aliphatic dicarboxylic acids such as acids, adipic acid, succinic acid, and oxalic acid.

In addition, as diol component units, diethylene glycol used in the present invention, in addition to ethylene glycol which is the main component, 1,3 propanediol, 1,4-butanediol, neopentyl glycol, cyclohexanediol, dichlorohexane dimetatool , 1,4-bis(β
-hydroxyethoxy)benzene, 1,3-bis(β-
hydroxyethoxy)benzene, 2,2-bis(4-β
-hydroxyphenyl)propane, 2,2bis(4-β
-hydroxyethoxyphenyl)propane, bis(4-
β-hydroxyethoxyphenyl) sulfone, bis(4
-β-hydroquinphenyl) sulfone, etc. can be used.

In the resin composition of the present invention, a polyfunctional component unit may be used as a moldability improving agent, and a polyfunctional component unit containing three or more carboxyl groups or hydroxyl groups, or a combination of carboxyl groups and hydroxyl groups The polyfunctional component unit may have three or more polyfunctional component units.

Specifically, trimellitic acid and trimesic acid.

Aromatic polybasic acids such as 3,3', 5,5'tetracarboxydiphenyl, aliphatic polybasic acids such as butane-tetracarboxylic acid, phloroglucinto 2,4,5-tetrahydroxybenzene, etc. Aromatic polyol, glycerin, trimethylolethane, trimethylolpropane,
Aliphatic polyols such as pentaerythritol, tartaric acid,
Oxypolycarboxylic acids such as malic acid can be exemplified.

As the catalyst used for the polymerization of the polyester resin composition of the present invention, any known catalyst used in the production of conventional PET can be used. As these catalysts, metals such as antimony, germanium, titanium, niobium, etc. or compounds thereof can be used. Specific examples include antimony trioxide, germanium dioxide, tetrabutoxytitanium, and niobic acid.

In the present invention, various conventionally known additives such as heat stabilizers, light stabilizers, anti-silting agents, lubricants, pigments, and dyes can be used during the polymerization of polyester.

Calcium, magnesium,
Metal compounds such as lithium, zinc, cobalt, manganese, etc.
Hydroxides, halogen compounds, inorganic acid salts, organic acid salts, etc. are used. In addition, as heat stabilizers, phosphoric acid and sulfuric acid 9
Phosphorus compounds such as hypophosphorous acid or esters thereof can be used.

As the polymerization method used in the present invention, known melt polymerization methods and solid phase polymerization methods can be used. In the melt polymerization method, a direct polymerization method or a transesterification polymerization method is generally used, and the polymerization is carried out at a temperature of 200 to 280°C and a vacuum degree of ITorr or less.In the solid phase polymerization method, a polymer obtained by melt polymerization is Furthermore, the molecular weight is elongated, and this is carried out under vacuum or inert flow at a temperature of 160 to 240° C. below the melting point.

The intrinsic viscosity of the resin composition of the present invention is 0.5 to 2. Od
1/g, especially for hollow molded bodies, 0.7 to 1.5 d
l/g, more preferably within the range of 0.8 to 1.3 dl/g.

The polymer of the present invention is usually pelletized and has a moisture content of 0.01%.
It is dried and used for molding. Vacuum drying conditions are 15 hours or more under vacuum at 60°C or higher, preferably 130 to 150°C.
, 20 hours or more The resin composition of the present invention is formed into a film by a known molding method.

It is stretched and used as sheets and containers.

The stretched product of the resin composition of the present invention may be either uniaxially or biaxially stretched, and its form is a film.

It can be a sheet, fiber, blow molded product,
The stretching ratio is 1.1 to 10 in uniaxial stretching, preferably 1
．． The range is 5 to 7 times, and in the case of biaxial stretching, any simultaneous or sequential stretching method may be used, and the range is 1.1 to 8 times, preferably 1.5 to 6 times, for each vertical axis and horizontal axis. . The stretched product can also be subjected to heat centing depending on its intended use.

The stretched product of the resin composition of the present invention may contain nucleating agents, inorganic fillers, lubricants, slip agents, anti-blocking agents, stabilizers, antistatic agents, anti-fogging agents, which are blended in conventional polyesters as necessary. There is no problem in adding appropriate amounts of various additives such as agents and pigments.

When producing a stretched molded product of the resin composition of the present invention, the polyester resin composition of the present invention and PET may be blended into pellets, or may be used for multilayer molding.

Stretched molded product of the resin composition of the present invention! ! As for the construction method,
When the molded product is a film or sheet, a method of stretching the unstretched film or sheet in a uniaxial direction;
A method of stretching in the longitudinal direction and then further stretching in the transverse direction, a method of simultaneously stretching both longitudinally and transversely, a so-called vacuum forming method in which stretch forming is performed by reducing the pressure in the space between a film or sheet-like object and a mold, etc. I can give an example.

When the molded product uses a parison, the molding can be carried out in the same way as a conventional PET resin blow molding machine.For example, extrusion blow molding, commonly called direct blow molding,
A molding method called injection blowing involves blow molding a parison with compressed gas before it is sufficiently cooled after injection molding, or a parison with a bottomed opening is created by injection molding or extrusion molding, and then stretched using a stretch blowing device at an appropriate temperature.
For example, a molding method called two-wheel stretch blow molding may be used, in which the temperature is controlled at 60 to 160° C. and blow molding is performed by stretching in the axial direction using a stretch iron and simultaneously or sequentially stretching in the circumferential direction using compressed gas. The hollow molded body obtained by the above method is stretched at least in a uniaxial manner at the inner thin part of the body.

The stretching ratio is preferably 2 times or more in area ratio (axial stretching ratio x circumferential stretching ratio), more preferably 3 times or more. The wall thickness of the body of the stretch-blown hollow molded body is usually 100 μm. or more, preferably 200 to 1000 μm
It is. In addition, after extrusion molding an unstretched sheet, the lid is integrated into a hollow molded body formed by deep drawing, or a cylindrical body obtained by stretching and orienting a pipe formed by extrusion or injection molding, as the case may be. It may also be a plastic can.

To describe the stretched hollow molded article of the present invention in more detail, it is a hollow molded article that has been stretched in at least one direction in its thin chest portion, has excellent gas barrier properties, and has little uneven thickness. The polyester resin composition used for the present hollow molded article preferably has crystallinity from the viewpoint of blow moldability, and has an intrinsic viscosity of 0.7 to 1.5 dl/g, and further 0.
．． It is preferably in the range of 8 to 1.3 di/g.

(Example) Hereinafter, the present invention will be explained in detail with reference to Examples.

The main measuring methods used in the present invention are as follows.

■ Measuring method of oxygen permeability Oxygen i3 permeability measuring device 0XTR manufactured by MOCON, USA
Measured at 30°C by AN (1) Measurement with stretched film (cc・mm/mt
・ATM・day) Measurement was performed using a film that was simultaneously stretched 3.5 times vertically and horizontally at 95°C.

(ii) Measurement using a hollow molded body (cc/piece, atm,
Measurements were made using a 11 hollow molded body blow molded using a Nissin ASB50 biaxial stretch blow molding machine.

■ Diethylene glycol content in chips (moj!
%) measurement method: 2.00 g of sample was added to 1N KOH methanol solution 5
After saponification with 0ml and neutralization with terephthalic acid, measurement was performed using a gas chromatograph.

■ Intrinsic viscosity (dj!/g) Phenol/l・1・2・2tetrachloroethane=6/
4 (weight ratio) Measured at 20°C using a mixed solvent.

Examples 1 to 4 and Comparative Example 1. 2 Bishydroxy engineered til terephthalate 10kg.

Terephthal #6.6kg, diethylene glycol (
335 g (hereinafter abbreviated as DEC) (3 mol % based on acid component unit), 1.43 kg ethylene glycol, 4 g trimethyl phosphoric acid (60 ppm based on polymer), 1.5 g germanium dioxide (10,100 ppm based on polymer) were added, and 250 g Esterification reaction for 3 hours at °C, then 27
A polyester was obtained by performing a vacuum polycondensation reaction at 5° C. and a vacuum degree of 0.5 Torr for 4 hours. Intrinsic viscosity is 0.705 dl
/g.

The pelletized polyester was vacuum dried at 140° C. for 24 hours and molded into a sheet with a thickness of 230 II m using a lab blast mill manufactured by Toyo Seiki Seisakusho.

Further, the sheet was simultaneously stretched at a stretching ratio of 3.5 times in both the vertical and horizontal axes to prepare a film, and the gas barrier properties were evaluated.

In Examples 2 and 3, the amount of DEC added per unit of anti-brewing component,
Comparative Example 1 is the same as Example 1 except that 5 mol% and 8 mol% are added.
A film was prepared in the same manner as in Example 1, except that 2 mol% of DEC was added to the acid-resistant component unit.

Further, in Example 4, Example 1 was further improved to 205°C×ITorr.
Intrinsic viscosity 11ffi0 solid-state polymerized for 26 hours in a vacuum of
．． It is a polyester of 99 dl/g.

The above results are summarized in Table 1. DEC component 3 of comparative example 2
．． At 4 mol %, no significant effect is observed, but as in Examples 1 to 3, when the DEG component is 4 mol % or more, the oxygen permeability, which indicates gas barrier properties, is clearly improved. Similarly, for Example 4 in which Example 1 was further solid-phase polymerized, gas barring Example 5 was obtained using the same method as Example 4, with a D E C of 10.5 mol % and an intrinsic viscosity of 0.95 d.
1/g of the polymer was made into a biaxially stretched blow molding machine with a length of about 2
11 with a minimum wall thickness of 300μm, stretched approximately 3.3 times in width and 3.3 times in width.
It is a hollow molded body, and Comparative Example 3 has a solid viscosity of 0.75 d.
This is a 1N hollow molded body made by molding conventional PET (DECm added) with a weight of 1/g in a similar manner.

Comparative Example 4 has an intrinsic viscosity of 1.0% when 10 mol% of the terephthalic acid component units of PET are replaced with isophthalic acid component units.
This is a hollow molded article 11 made by molding a copolymerized polyester resin of 0 dffi/g in the same manner.

The above results are summarized in Table 2.

Comparative Example 4 was made of a composition with excellent gas barrier properties, but the thickness unevenness was so significant that it was practically unusable. Example 5 has less uneven thickness and is lower than the conventional comparative example 3 (effects of the invention) As described above, the polyester resin composition of the present invention and its stretched product have excellent gas barrier properties, melt moldability, and transparency, and can be used for containers, etc. Useful as packaging material.

Claims (3)

[Claims] (1) In a polyester produced from a diol component unit containing ethylene glycol as a main component and a dicarboxylic acid component unit containing terephthalic acid or its ester-forming derivative as a main component, diethylene glycol accounts for 4 mol% or more as the diol component unit. A polyester resin composition with excellent gas barrier properties. (2) A stretched product made of the polyester resin composition according to claim 1. (3) The hollow molded product according to any one of claims 1 to 2, wherein the stretched product is a hollow molded product, and the thin body portion thereof is stretched in at least one direction.