JPS61211360A - Thermoplastic polyester composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. having excellent mechanical characteristics and gas barrier properties, by mixing polyethylene terephthalate with a polyester contg. bis(2-hydroxyethoxy)benzene as a diol component. CONSTITUTION:A thermoplastic polyester compsn. is obtd. by blending a polyester (A) mainly composed of an ethylene terephthalate unit with a polyester (B) composed of an acid component consisting of terephthalic and/or isophthalic acid and a diol component consisting of bis(2-hydroxyethoxy)benzene or a mixture thereof with other diol in a weight ratio of A to B of 95:5-5:95, pref. 90:10-10:90. Optionally, additives such as antioxidant, lubricant, ultraviolet absorber, colorant, filler, plasticizer, etc., may be added to the compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a thermoplastic polyester composition, and more particularly to a thermoplastic polyester composition that has an excellent combination of mechanical properties such as moldability, impact resistance, and creep resistance, and gas barrier properties. The present invention relates to thermoplastic polyester compositions.

Conventional technology Polyethylene terephthalate has excellent mechanical properties such as formability and creep resistance, and because it is capable of biaxial molecular orientation, it has excellent creep resistance, impact resistance, rigidity, gas barrier properties, and light weight. It has come to be widely used as a lightweight glass container with excellent durability and transparency, especially as a pin for beverages. However, the gas permeability of polyester bottles is still not negligible compared to glass bottles, and for example, the shelf life of polyester bottles of 1 liter or less filled with carbonated drinks such as cola is
It is said to last about two months at most.

On the other hand, olefin-vinyl alcohol copolymers such as ethylene-vinyl acetate are known as resins with excellent gas barrier properties. It has also been proposed to use alcohol copolymers as a container in the form of a laminated structure. It is predicted that such a laminated structure will have an excellent combination of gas barrier properties, creep resistance, impact resistance, rigidity, etc., but there are Because it is difficult to form a strong glabellar bond, it has not yet been put to practical use in containers, especially biaxially stretched blow-molded containers.

An object of the present invention is to provide a thermoplastic polyester composition which itself has an excellent combination of mechanical properties such as moldability, impact resistance and creep resistance, and gas barrier properties.

Another object of the present invention is to provide a thermoplastic polyester resin composition that has excellent adhesion to an ethylene-vinyl alcohol copolymer.

Still other objects of the present invention are 1. It is an object of the present invention to provide a thermoplastic polyester resin composition that is particularly useful for use as a stretch-produced container or a sheet-molded container by stretching.

Structure of the Invention According to the present invention, (4) a polyester mainly composed of ethylene terephthalate units, and (B) terephthalic acid and/or
Or a polyester consisting of an acid component consisting of inphthalic acid and a diol component consisting of bis(2-hydroxyethoxy)benzene or a combination thereof with another diol in a weight ratio of A:B = 95:5 to 5:95. Provided is a thermoplastic polyester composition comprising:

That is, the present invention provides that when polyester containing bis(2-hydroxyethoxy)benzene as a diol component in its main chain is blended with polyethylene terephthalate, gas barrier properties can be achieved without impairing the mechanical properties such as the excellent moldability of polyethylene terephthalate. This is based on the new finding that a polyester composition with significantly improved properties can be obtained.

Preferred embodiments of the invention The invention will be explained in detail below.

Fat component In the polyester composition of the present invention, the polyester used as one component includes terephthalic acid and isophthalic acid as acid components, each singly or in combination. In this case, when at least 5 moles of isophthalic acid are used in proportion to the total acid components, a composition having excellent adhesion to ethylene-vinyl alcohol copolymer can be obtained. This is because polyesters or copolyesters having isophthalic acid in the main chain tend to have a bent structure in their polymer side chains compared to polyesters consisting of p-oriented terephthalic acid units, and ethylene-vinyl alcohol copolymer This seems to be because the affinity with coalescence increases.

As the diol component, bis(2-hydroxyethoxy)benzene, particularly 1,3-bis(2-hydroxyethoxy)benzene, is used alone or in combination with other diol components. In the present invention, it is necessary that the diol having an aromatic group is contained in the polyester main chain in an amount of at least o, ooi mol, particularly in the range of 0.01 to 90.0 mol, based on the total amount of the diol component. DeL gnya+111-+A-L-9-m,+
11 Yu? A 8/11 If there is less w - w, the gas barrier property will be unsatisfactory, and 9
When the amount is more than 0.0 mole, the polyester main chain contains many relatively hard ester segments derived from aromatic components, which tends to result in unsatisfactory moldability and the like. That is, when the aforementioned diol component having an aromatic group is contained in the polyester main chain within the above range, a polyester composition having an excellent combination of gas barrier properties, moldability, etc. can be obtained. Further, when such a diol component is contained in the polyester main chain, the advantage that the adhesive ability with the ethylene-vinyl alcohol copolymer is increased is also achieved.

As other diol components that can be combined with bis(2-hydroxyethoxy)benzene, all diols capable of forming esters can be used, such as ethylene glycol, propylene glycol, 1,4-butanediol, and neopentyl glycol. , cyclohexanediol, xylylene glycol, hexahydroxylylene glycol, bis(4-β-hydroxyethoxyphenyl)sulfone, and the like can be used.

The polyester used in the present invention is an ester repeating unit derived from the above-mentioned acid component and diol, i.e., in the formula, R1 is an aromatic group j5, and R2 is at least +! of all R2 groups. :40.001molti is mainly formed from repeating units of 1 group derived from bis(2moldroxyethoxy)benzene, but may contain a small amount of 9 other ester repeating units as long as this essence is not impaired. There is no harm in doing so. Generally, the molecular weight may be within a range that provides film-forming ability.

Moreover, this polyester is generally prepared at 30°C in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 60:40.
0.3 to 2.8 dV11 especially 0.4 when measured at a temperature of
It is preferable to have an intrinsic viscosity [η] of from 1.8 dvg to 1.8 dvg. Furthermore, from the viewpoint of thermal bonding workability, it is preferable that the resin has a ring and ball softening point of 230°C or less, particularly from -30 to 200°C.

In the present invention, polyethylene terephthalate is used as another component used in combination with the above-mentioned polyester from the viewpoint of moldability, mechanical strength, water resistance, etc. Of course, copolyesters containing small amounts of other ester repeating units can also be used within a range that does not impair these properties. In particular, in order to improve various properties during thermoforming, it is preferable to include a small amount of comonomer in the main chain. Modified PET etc. containing small amounts of are preferably used for the purpose of the present invention. In general, the molecular weight may be within a range that provides film-forming ability.

Composition The thermoplastic polyester composition of the present invention comprises (4) polyethylene terephthalate) and (B) a polyester having the above-mentioned specific diol component in the main chain, in a ratio of A:B=95.
:5 to 5:95 Especially when polyethylene terephthalate is used in a larger amount than the above range, gas barrier properties and ethylene-vinyl alcohol co-existence may be affected. The adhesion ability with other resins such as polymers becomes insufficient, and when used in an amount smaller than the above range, the stretchability tends to decrease. There are no limitations, and a resin composition for molding can be easily obtained, for example, by melt blending or triblending. From the point of view of preventing thermal deterioration, triblend is preferable, and the triblend is fed to a molding extruder or injection machine, and mixing is performed by a screen in the extruder or injection machine.

The resin composition of the present invention may contain compounding agents known per se, such as antioxidants, antistatic agents, lubricants, ultraviolet absorbers, colorants, fillers, and enhancers according to known formulations.

Furthermore, during extrusion molding, the resin composition of the present invention has a difference in average flow velocity of polyethylene terephthalate melt of 1 m/
If conditions are adopted such that the ratio of polyethylene terephthalate is preferentially distributed in the thickness direction of the blend, the layer (a) in which polyethylene terephthalate is preferentially distributed and the layer (b) in which the polyester is preferentially distributed are In such a case, the polyester having good gas barrier properties is distributed in layers, so that excellent gas barrier properties are exhibited. Alternatively, the dilyethylene terephthalate layer may be provided so as to face the layer (,) in which polyethylene terephthalate is preferentially distributed, or the polyester layer (b) may be provided so as to face the ethylene-vinyl alcohol copolymer layer. , it becomes possible to form a strong bond between these layers.

Of this invention? The lyester composition has excellent properties in terms of sparring properties and elongation, and provides significant advantages in terms of workability in stretch molding.

Application The resin composition of the present invention has excellent gas barrier properties and moldability, as well as excellent adhesion to je IJ esters such as ethylene-vinyl alcohol copolymer and polyethylene terephthalate. As well,
To further improve the properties of the resin, it can be thermoformed in the form of a laminate with the resin into a film, sheet, mold or preform. For thermoforming, a molding method known per se such as extrusion molding, injection molding, and silicone molding can be employed. In order to form a film or the like in the form of a laminate, an extruder for the resin composition of the present invention and an extruder for the other resin to be laminated are used to place both phase resin layers in adjacent positions. In this case, coextrusion through multiple multilayer dies is preferably employed.

As a laminate, a laminate with a polyester such as polyethylene terephthalate and/or an ethylene-vinyl alcohol copolymer is advantageous, but in the case of a three-layer structure with the above resins, the resin composition of the present invention may be used. Use as a middle layer.

The above-mentioned film, sheet, etc. can be made into a cup-shaped container in which the side wall has molecular orientation in a uniaxial direction by subjecting it to draw-forming, pressure-forming, gun-assist molding, etc. at a stretching temperature. . In addition, by mechanically stretching Parinone or a preform at a stretching temperature in the axial direction and blow-stretching it in the circumferential direction by blowing fluid, it is possible to obtain yN in which the side wall portion has molecular orientation in biaxial directions. )
It can be made into a bottle-shaped container.

The invention is illustrated by the following example.

Synthesis of polyester Specified acid components and diol components are charged into a glass reactor along with a small amount of catalyst such as titanyl acetylacetonate, heated to 200°C under a nitrogen gas atmosphere, and reacted for about 100 minutes while removing generated methanol. After increasing the reaction temperature to 250°C and maintaining it for about 1 hour, the supply of nitrogen gas was stopped and the reaction temperature was increased to 250°C under reduced pressure of 0.4 mHg or less.
Polymerization was carried out at a temperature of 75° C. for about 3 hours. Table 1 shows the compositions of the acid component and diol component of each of the polyester samples obtained. The final composition of the sample was confirmed by proton NMR and gas chromatograph 2F analysis.

Table 1 *T represents terephthalic acid, ■ represents isophthalic acid.

Example 1 The polyester of Sample 3 in Table 1 was used, and the intrinsic viscosity at 30°C was 0 in a mixed solvent of this polyester and phenol/tetrachloroethane at a weight ratio of 50150.
．． 91 di/9 polyethylene terephthalate resin (
PET) were mixed at room temperature for 10 minutes using a Henschel type dry blender at various mixing ratios.

Each of these mixtures has a diameter of 50 dew and an effective length of 1100 m.
A sheet with a width of 150+m and a wall thickness of 0.5-m was formed using a T-die using an extruder.

Next, the elongation (elongation at break/initial length x 100, unit %) up to break in the longitudinal direction (extrusion direction, MD) and transverse direction (TD) of each sheet obtained was measured using a tensile tester (Toyo Manufactured by Pouldwin, Tensilon UTM-I
The tensile speed was 200 m/mi at room temperature.
A tensile test was conducted under the conditions of n.

Figure 1 shows the relationship between the elongation at break in the longitudinal direction (extrusion direction, MD) of the sheet and the mixing ratio of each mixture, and Figure 2 shows the relationship between the elongation at break in the transverse direction of the sheet and the mixing ratio of each mixture. 〇Example 2 For each polyester sample shown in Table 1, PET used in Example 1 was used, and the mixing ratio was varied to make Example 1.
A sheet was created by blending and melt extrusion in the same manner as above. Each sheet was further stretched using a biaxial stretching machine manufactured by Wakagi Seisakusho Co., Ltd. at 120°C and a stretching speed of 300 w/min. Stretch, 120
After being left at ℃ for 10 minutes, the oxygen permeability coefficient (Po2) of each of these stretched sheets and an unstretched sheet as a control was determined.
was measured at 27° C. and 604 RH using a gas permeation tester manufactured by Toyo Tester Kogyo Co., Ltd. Second result
Shown in the table.

[Brief explanation of drawings]

Figures 1 and 2 show the longitudinal direction (MD
) and the elongation at break in the transverse direction (TD). Figure 1 MO (-M) Tensilon tJTM-1

Claims (1)

[Claims] (1) Consists of (A) a polyester mainly composed of ethylene terephthalate units, and (B) a combination of an acid component consisting of terephthalic acid and/or isophthalic acid and bis(2-hydroxyethoxy)benzene or this and other diols. A thermoplastic polyester composition comprising a diol component and a polyester in a weight ratio of A:B=95:5 to 5:95.