JPS61211037A - Laminated structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 1 prong” J ■ Phantom 1 outside! The present invention relates to a laminated structure, and more particularly to a laminated structure that is excellent in various properties such as processability, interlayer adhesion, and gas barrier properties.

'Next Technology and Technical Issues to be Decided Polyethylene terephthalate has excellent mechanical properties such as formability and creep resistance, and because it is possible to orient molecules in the direction of the two wheels, it has excellent creep resistance and impact resistance. ,
It has come to be widely adopted in the field of lightweight plastic containers due to its excellent rigidity, gas barrier properties, light weight, transparency, etc.

However, the gas barrier properties of polyester containers are still not negligible compared to, for example, glass bottles, and the shelf life of small polyester bottles of 1 liter or less filled with carbonated drinks such as cola is only 2 months at most. It is said that the degree of

On the other hand, ethylene-vinyl alcohol copolymer is known as a resin that has excellent oxygen barrier properties and can be aged.
It has already been proposed to use polyester and this ethylene-vinyl alcohol copolymer as a container in the form of a laminated structure, and such a laminated structure has gas barrier properties, creep resistance, and impact resistance. It is naturally expected that this material will be excellent in combination with , rigidity, etc.

However, since a strong interlayer bond cannot be obtained between the ethylene-vinyl alcohol copolymer and the polyester, the above-mentioned laminate has not yet been put into practical use for containers, especially biaxially stretched blow-molded containers. The current situation is that this has not been achieved.

An object of the present invention is to provide a laminated structure of polyethylene terephthalate and a resin that has excellent gas barrier properties in place of ethylene-vinyl alcohol copolymers.

Another object of the present invention is to form a strong interlayer bond between a layer made of polyethylene terephthalate and a gas barrier layer, and to improve mechanical properties such as moldability, impact resistance, and creep resistance, and gas barrier properties. The purpose is to provide a laminated structure with excellent combinations.

According to the present invention, (A) a layer of polyester mainly composed of ethylene terephthalate units, (B) an acid component consisting of terephthalic acid and/or inphthalic acid, and bis(2-
A polyester or copolyester containing benzene (hydroxyethoxy)benzene or a diol thereof in the main chain is located adjacent to the polyester or copolyester with a layer mainly composed of a blend of the polyester and the copolyester. A laminated structure is provided, characterized in that they are arranged in relationship.

That is, in the present invention, a layer mainly composed of polyester or copolyester having bis(2-hydroxyethoxy)benzene in the main chain as a diol component is used as a gas barrier layer, and this layer is used as a gas barrier layer between the above polyester or copolyester and polyethylene terephthalate. When laminated to a polyethylene terephthalate layer through an adhesive layer made of a blend of This is based on the new finding that a laminated structure with an excellent combination of mechanical properties such as creep resistance and gas barrier properties can be obtained.

i Mitate Beni 111 Polyethylene terephthalate In the present invention, polyethylene terephthalate (hereinafter referred to as (sometimes simply called PET)
However, within a range that does not impair the excellent properties such as polyethylene terephthalate's moldability, it can also be used in a blend with polybutylene terephthalate, polycarbonate, or Nananoike's thermoplastic resin.

In addition, in order to improve various physical properties during thermoforming, it is acceptable to include a small amount of comonomer in the main chain. For example, in order to improve drawdown properties during molding, a small amount of hexahydroxylylene glycol as a glycol component is acceptable. Modified PET containing PET etc. are used for the purpose of the present invention.

The polyester should also generally have sufficient molecular properties to form a film.

L5 Bayueni 1 In the laminate structure of the present invention, the acid component is terephthalic acid and/or inphthalic acid as a gas barrier, and the diol component is bis(2-hydroxyethoxy)benzene alone or other diols. A polyester or copolyester is used in combination with.

As this bis(2-hydroxyethoxy)benzene, in particular 1,3-bis(2-hydroxyethoxy)benzene is used, and the diol containing this aromatic group is at least 0.001% based on the total amount of diol components. It is necessary that the main chain of the polyester contains at least mol %, preferably at least 0.01 mol 5. By including this bis(2-hydroxyethoxy)benzene in the main chain of the polyester, gas barrier properties are dramatically increased, as is clear from the examples described later, and the aromatic group in the main chain is It is thought that as the proportion occupied by segments increases, strong interlayer bonds are likely to be formed between polyethylene terephthalate and polyethylene terephthalate having similar aromatic groups.

As other diols that can be used in combination with bis(2hydroxyethoxy)benzene, all diols having ester-forming ability can be used, such as ethylene glycol, propylene glycol, 1,4-butanediol, neo Examples include pentyl glycol, cyclohexanediol, xylylene glycol, hexahydroxylylene glycol, and bis(4-β-hydroxyethoxyphenyl)sulfone.

In the present invention, this polyester is an ester repeating unit derived from the dibasic acid and diol described above, ie, the formula: where 11 is an aromatic group and R2 is all R? At least 0.001 mol% or more of the group is a group derived from bis(2-hydroxy)benzene, and is mainly formed from repeating units of There is no problem even if it contains repeating units.

In addition, this polyester is generally prepared in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 80:40.
Preferably, it has an intrinsic viscosity [η] of 0.3 to 2.8 dl/g, particularly 0.4 to 1.8 dl/g, when lower than 0.3 dl/g, when measured at a temperature of 5°C. The mechanical strength of the molded product is unsatisfactory in 2.
When it is higher than 8 dl/g, the moldability of the laminate tends to decrease.

Furthermore, from the viewpoint of thermal adhesion, it is preferable that the resin has a ring and ball softening point of 230°C or less, particularly from -30 to 200°C.

Further, the molecular weight may be within a molecular weight range that generally provides film-forming ability.

1 m In the present invention, a gas barrier layer made of polyester containing the above-mentioned specific diol component in its main chain and a polyethylene terephthalate layer are laminated via an adhesive layer.

As this adhesive layer, a blend of a specific polyester or copolyester used for the gas barrier layer and polyethylene terephthalate is used.

In such a blend, since the polyester or copolyester used in the gas barrier layer and polyethylene terephthalate are contained, it exhibits significantly excellent adhesion to the gas barrier layer and PETH,
A strong interlayer bond is thus formed between the gas barrier layer and the PE7 layer.

Such a blend comprises polyester or copolyester (a) containing the above-mentioned specific diol component in its main chain and polyethylene terephthalate (b) in a ratio of a:b-99:l to 1:99, particularly 95 Blending at a weight ratio of :5 to 3:97 is suitable for obtaining a laminate having excellent living room peeling resistance.

However, even if a blending ratio outside this preferred range is adopted, for example, by adjusting the extrusion speed of each component during extrusion molding, the specific polyester or copolyester (a) in the blend layer may be lower than the average value. forming a multilayer structure of a layer containing a large amount of polyethylene terephthalate (b) and a layer containing a larger amount of polyethylene terephthalate (b) than the average value,
By positioning the layers so that they face the gas barrier layer and the polyethylene terephthalate layer, it is possible to firmly bond the layers.

As each component of these blends, a polyester or copolyester having polyethylene terephthalate and a specific diol component in the main chain, which can be used in the polyethylene terephthalate layer and the gas barrier layer, can be used as is.

In the present invention, the polyethylene terephthalate layer and the gas barrier layer may be formed into a laminated structure by using the above-mentioned resin components as they are or by adding a compounding agent thereto by a molding method known per se such as co-extrusion molding or co-injection molding. I can do it.

For example, for use as a food packaging agent, it is preferable to directly apply the laminated molding operation without using so-called compounding agents, but if necessary, well-known compounding agents such as ultraviolet absorbers, stabilizers, lubricants, oxidizing agents, etc. inhibitors, pigments, dyes,
It is possible to incorporate antistatic agents and the like into known formulations.

The laminated structure of the present invention includes a polyethylene terephthalate layer (7 PE layers), a gas barrier layer mainly composed of a boa polyester or copolyester having a specific diol component in the main chain, and an adhesive layer (AD For example, the following cross-sectional arrangement may be adopted within the range that satisfies the condition of lamination via layers (layers).

■, 3-layer PET layer/AD layer/barrier layer ■, 5-layer structure PET layer/AD layer/barrier Jfj/AD layer/PET layer barrier single layer/AD layer/PET layer/AD layer/barrier layer Although it is possible to further improve gas barrier properties etc. by using a multilayer structure, in the normal case, the object of the present invention can be sufficiently achieved with the above-mentioned three to five layer structure.

The thickness of each layer constituting such a laminated structure can be arbitrarily changed depending on the use described below, but
In order to obtain the optimum combination of mechanical properties such as delamination resistance and impact resistance, PET layer=AD layer:one barrier layer=99:0.01:0.99 to 5:45:
50 especially 99:0,05:0.95 to 5:4
It is preferable to set the wall thickness ratio in the range of 0:55.

In the laminate structure of the present invention, a polyester or copolyester containing bis(2-hydroxyethoxy)benzene as a diol component in its main chain and having high gas barrier properties itself is used as the gas barrier layer, and this is applied to a predetermined adhesive layer. Since it is laminated with a polyethylene terephthalate layer via a layer, it is possible to obtain significantly higher gas barrier properties than when polyethylene terephthalate is used alone. Moreover, since the adhesive layer uses a blend of the resin components constituting each layer to be laminated, a remarkable advantage is achieved in that a strong interlayer bond is formed between both layers. In addition, since each component of the blend contains the same type of aromatic ester segment in its main chain, it has a high chemical affinity and can be easily blended.

In addition, the constituent component of each layer is polyethylene terephthalate or a polyester having a similar chemical structure,
In addition to the above-mentioned properties, the laminated structure of the present invention has excellent mechanical properties such as moldability and impact strength.

It is best to form the laminate by multi-layer co-extrusion. According to this multi-layer co-extrusion, both resins are mixed well at the adhesive interface between the resins, which improves the adhesive strength. A particularly excellent laminated structure can be obtained.

For multilayer coextrusion, PET, a polyester or copolyester having a specific diol component, and a blend thereof are melt-kneaded in respective extruders, and then passed through a multilayer die to form the layer configurations of Steps to II described above. It is extruded and formed into films, sheets, bottle pipes, bottle preforms, etc.

In the case of bottle preforms, a multi-layer co-extruded molten resin parison is pre-produced in a mold, or a multi-layer co-extruded pipe is cooled and cut into a certain size, and then the upper end of the pipe and It is obtained by reheating the lower end portion and molding the mouth thread portion and the bottom portion by means such as compression molding.

The laminate can also be formed by a method called sandwich lamination or extrusion coating. For example, a laminate can be produced by pressing together a preformed polyethylene terephthalate film, a polyester or copolyester film having a specific diol component, and a blend film under heat. Another method is to extrude a blend as an intermediate layer between a polyethylene terephthalate film and the above polyester or copolyester film, and then press the extruded layer between these two films in a sandwich shape to obtain a shoe body. You can also do it. Alternatively, a method of hot-pressing or hot-rolling preformed various films in a predetermined lamination order can also be adopted.

Of course, in addition to the method described above, the laminate can also be obtained by, for example, using a molding machine having a plurality of cylinders and sequentially or co-injecting each predetermined resin.

The laminated structure of the present invention is particularly useful as a stretch-blow-molded container or a sheet-molded container by stretching.

For example, stretch blow molding is performed by means known per se, except that the multilayer preform described above is used. First, prior to stretch blowing, this multilayer preform is preheated to a stretching temperature, which is a temperature lower than the crystallization temperature of the polyester used and at which the multilayer preform can be stretched. For example, in the case of polyethylene terephthalate, 80 to 13
Temperatures of 0°C, especially 90 to 110°C are used.

Stretch blow molding of the preheated preform can be carried out by means known per se, such as sequential stretch blow molding or simultaneous stretch blow molding.

For example, in the former case, the preform is stretched axially under fluid injection at a relatively low pressure, and then stretched [11J] in the circumferential direction of the container under fluid injection at a relatively high pressure.
Stretching is performed by M. In the latter case, stretching in the circumferential direction and stretching in the axial direction are performed simultaneously by blowing fluid at high pressure from the beginning. The preform can be easily stretched in the axial direction by, for example, holding the neck of the preform between a mold and a mandrel, applying a stretching rod on the inner surface of the bottom of the preform, and stretching the stretching rod. The stretching ratios of the preform in the axial direction and circumferential direction are 1.5 to 2.5 times (axial direction) and 1.7 times, respectively.
It is desirable to set it to 4.0 (circumferential direction).

In the body of the container stretch-blow-molded in this way, the polyethylene terephthalate layer has a density of 1.
．． The polyester or copolyester is molecularly oriented in the range of 350 to 1.402 g/cc, and provides desirable impact resistance, rigidity, transparency, etc. for bottle-shaped containers, and also contains a specified diol component in the main chain. The presence of the gas barrier layer made of polyester provides excellent barrier properties against gases such as oxygen, nitrogen, carbon dioxide, and fragrance. Moreover, by interposing the blending physics of the constituent components of each layer between these two layers, excellent living room adhesive resistance is maintained.

In addition, in a sheet-formed container, the multilayer film or multilayer sheet described above is preheated to the stretching temperature described above, and the heated film or the like is formed into a cup shape by means such as vacuum forming, pressure forming, plug assist forming, or press forming. Form into.

The invention is illustrated by the following example.

A mixture of terephthalic acid and inphthalic acid as a synthetic acid component of polyester,
and bis(2-hydroxyethoxy)benzene (BHEB) and ethylene glycol (
A mixture of E and G) was charged into a glass reactor together with a small amount of a catalyst such as titanyl acetenate, heated to 200°C under a nitrogen gas atmosphere, and reacted for about 100 minutes while removing methanol generated. Then, after raising the reaction temperature to 250°C and maintaining it for about 1 hour, the supply of nitrogen gas was stopped and the temperature was reduced to 0.4 msHg or less.

Polymerization was carried out at a temperature of 275° C. for about 3 hours.

Final composition of the obtained polyester (proton NMR,
Confirmed by analysis by gas chromatography), the molar ratio of terephthalic acid component and inphthalic acid component is 70:30.
The molar ratio of BHEB and EG acid components was 20:80.

Example 1 Polyester synthesized in the previous section and polyethylene terephthalate (phenol/tetrachloroethane weight ratio 5)
Intrinsic viscosity at 30°C in a mixed solvent of 0.0750: 0.9
A sheet with a thickness of 1.5 mm was obtained by extrusion sheet molding of 1 dl/g, ).

Further, this synthetic polyester and boaryethylene terephthalate were mixed in a Henschel type dry blender at various mixing ratios to obtain blends. This blend was sandwiched between two Teflon sheets and molded by hot pressing to create a film-like sheet with a thickness of about 11,001 L.

A film sheet made of this blend is made of the synthetic polyester sheet and polyethylene terephthalate (
PET) sheets, and in a stacked state, held in a hot press maintained at about 250°C for 120 seconds without applying pressure, then pressurized to 5 kg/cm2, and
A laminate was created by holding for 0 seconds.

Furthermore, a part of this laminate was processed using a research biaxial stretching device BISTROM B? manufactured by Karamoto Seisakusho. A sample was prepared by stretching 2 times in the uniaxial direction at a stretching temperature of 120° C. using Type-1.

figure! A test piece of length IOC)wm and width 1OII11 was cut out from the sheet immediately after adhesion and the sheet further stretched (for the latter, the stretching axis coincides with the longitudinal direction), and the test piece was cut out using a tensile tester. Use at room temperature.

A T-peel test was conducted at a tensile speed of 100 tmm/aim.

Further, the above test piece was stored in an atmosphere of 37° C. and 97% relative humidity for one month, and then a similar test was conducted.

Measurements were carried out five times under each condition, and all were 1t5 below peeling (cohesive failure in blend physics).

Example 2 The synthetic polyester resin described above was used as the resin for the outer layer, Example 1
The polyethylene terephthalate (PET) used in Example 1 was used as the resin for the inner layer, and the various blends used in Example 1 were used as the resin for the intermediate layer. Using an extrusion molding device that combines a triple die for layers, a three-layer pipe of synthetic polyester/various blends/PET was melt-extruded and pre-blow molded in a 10% mold to have an inner diameter of 27.7 mm and a length of 13 mm.
81 sets of bottomed preforms having an average wall thickness of 35 mm were molded.

The extrusion conditions were set so that the wall thickness ratio of the outer radius: middle radius: inner layer of this preform was 1:1:4.

Each of these bottomed preforms was heated with an infrared heater and sequentially biaxially stretched blow molded to an axial stretching ratio of 2.
0 times, stretch blow molded so that the circumferential direction stretch ratio is 3.0 times, the average wall thickness is about 0.40 ■ layer, and the internal volume is about 1 ton.
A total of six types of three-layer bottles were manufactured.

For comparison, polyethylene terephthalate (PE
A bottomed preform having the same dimensions as above was molded using only T), and then a biaxially stretched blow bottle having the same dimensions was manufactured in the same manner as above.

For these sample bottles, the oxygen gas permeability (Q
O2) and drop strength (lo) were measured and the results are shown in Table 2.

The above test was conducted according to the following measurement method.

(1) Oxygen gas permeability, QO2: The inside of the bottle to be measured is exchanged with nitrogen gas in a vacuum, the mouth of the bottle is sealed with a rubber stopper, and the contact surface between the mouth and the rubber stopper is sealed with epoxy. After covering the bottle with adhesive, the bottle was stored in a constant temperature and humidity chamber at a temperature of 37°C and a humidity of 15% RH for a certain period of time, and the concentration of oxygen that permeated into the bottle was determined using a gas chromatograph, using the following formula. oxygen gas permeability,
QO2 was calculated. Results are average values of N=3.

E where m: Amount of nitrogen gas filled into the bottle [1] t: Storage period (day) in the hot tank, ctHt Oxygen concentration in the white hole after days (Vo1%).

A: Effective surface area of the bottle [ml], Op: Oxygen gas partial pressure (=0.209.) (αt77!]
, (il) Drop strength, f10 10 bottles per type were filled with a constant weight of ★ salt water, the mouth was sealed with a cap, and then left standing in an atmosphere at -2°C for two days and nights. After that, the bottle was heated to 300℃ at a temperature of 20℃.
The bottle was dropped from a height of 1.5 cm onto a concrete surface so that the bottom of the bottle touched the concrete surface. The number of drops was up to 10 times (this was repeated). The drop strength, 8., was calculated according to the following formula from the number of bottles that remained undamaged after being dropped 10 times.

Here, N: number of tests (=10)C] is. ; Number of bottles that remained undamaged after being dropped up to 10 times.

Chapter 1 Table →No synthetic polyester layer and blending physics.

-The thickness ratio of the synthetic polyester layer and PET layer is 1:6 (
(no blending physics).

Claims (1)

[Claims] (1) (A) A layer of polyester mainly composed of ethylene terephthalate units, (B) an acid component consisting of terephthalic acid and/or inphthalic acid, and bis(2-hydroxyethoxy)benzene or this and other diol. A laminate characterized in that a layer mainly composed of polyester or copolyester contained in the main chain is provided in an adjacent positional relationship via a layer mainly composed of a blend of the polyester and the copolyester. Structure.