JPH0243628B2 - PURASUCHITSUKUSEKISOKOZOTAIOYOBYOKI - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a plastic laminated structure, and more specifically, a creep-resistant resin layer typified by polyethylene terephthalate and an olefin resin layer.
The present invention relates to a plastic laminate structure comprising a gas barrier layer made of a vinyl alcohol copolymer, both of which are firmly bonded by a copolyester adhesive layer. Furthermore, the present invention has excellent combinations of gas barrier properties, creep resistance, rigidity, impact resistance, delamination resistance, and transparency, and is useful for sealed long-term storage of various contents such as foods. Relating to multilayer plastic containers. Polyethylene terephthalate has excellent mechanical properties such as moldability and creep resistance, and because it is capable of biaxial molecular orientation, it has excellent creep resistance, impact resistance, rigidity, gas barrier properties, light weight, and Lightweight plastic containers with excellent transparency have come to be widely used, especially as beverage bottles. However, the gas permeability of polyester bottles is still not negligible compared to glass bottles, and for example, a small polyester bottle of 1 liter or less filled with carbonated drinks such as cola has a shelf life of at most 2 months. It is said that the degree of On the other hand, olefin-vinyl alcohol copolymers such as saponified ethylene-vinyl acetate copolymers,
This material is well known as a thermoformable resin with excellent oxygen barrier properties, and it is already known that this resin can be combined with an olefin resin with excellent moisture resistance to make unstretched or stretched multilayer plastic containers. There is. It has already been proposed to use polyester and olefin-vinyl alcohol copolymer as containers in the form of a laminated structure, and such a laminated structure has gas barrier properties, creep resistance, impact resistance, It is naturally expected that such laminated structures will be superior in combination with rigidity, etc., but such laminated structures are
The reason why it has not yet been put into practical use, especially for biaxially stretched blow-molded containers, is that thermoplastic adhesives have not been found to form strong interlayer bonds between polyester and olefin-vinyl alcohol copolymers. This seems to be because there is no such thing. The present inventors have discovered that a thermoplastic resin adhesive mainly composed of a specific copolyester described below can firmly bond a creep-resistant resin layer such as polyester or polycarbonate and an olefin-vinyl alcohol copolymer layer in a molten state. It has been found that the bonding and interlayer adhesive strength are not lost even under container forming conditions such as blow molding, stretch blow molding, and drawing. That is, an object of the present invention is to combine a creep-resistant resin layer such as polyethylene terephthalate and an olefin resin layer.
To provide a plastic laminate structure in which a vinyl alcohol copolymer layer is firmly bonded. Another object of the present invention is to provide a plastic laminate which has excellent gas barrier properties, creep resistance, impact resistance, rigidity, heat resistance, delamination properties, and even transparency and is useful as a sealed container in the form of a bottle or cup. Provides a structure. According to the present invention, a creep-resistant resin layer containing ester repeating units as a main component and a gas barrier resin layer containing an olefin-vinyl alcohol copolymer are combined so that 95 to 40 mol% of the total dibasic acid component is terephthalate. A plastic laminate structure is provided which is laminated via an adhesive layer containing a thermoplastic copolyester or copolyester composition containing 5 to 60 mol% of isophthalic acid. The present invention further provides a sealed multilayer plastic container comprising the above-described laminate. The invention will be explained in detail below. In FIG. 1, which shows an example of a plastic laminated structure in the shape of a bottle, this container includes a body 1 integrally formed by stretch blowing from a multilayer preform, which will be described in detail later, a bottom 2 continuous to the lower end of the body, and a body. It consists of a frustum-shaped shoulder 3 that continues to the upper end of the section, and a neck 4 that continues to the upper end of this shoulder. This bottle is formed by biaxially stretch-blow molding a preform, that is, by mechanically stretching it in the axial direction of the container and blow-stretching it in the circumferential direction by blowing fluid into the preform.
The resin constituting the bottle has molecular orientation in biaxial directions, that is, in the axial direction of the bottle and in the circumferential direction of the bottle. The second image shows an enlarged cross-section of the body wall of this bottle.
In the figure, the vessel wall of this specific example has an inner surface layer 5 made of polyester mainly composed of ethylene terephthalate units, an outer surface layer 6 made of the same polyester, and an olefin layer interposed between them.
It consists of an intermediate gas barrier layer 7 containing a vinyl alcohol copolymer, and these polyester layers 5
and 6 and the gas barrier layer 7 are firmly thermally bonded via copolyester-containing adhesive layers 8 and 9, which will be described in detail below. That is, in the present invention, the creep-resistant resin layers 5 and 6 and the olefin-vinyl alcohol copolymer-containing gas barrier layer 7 contain 95 to 40 mol%, particularly 85 to 50 mol% of the total dibasic acid component, of terephthalic acid. and at least one thermoplastic copolyester consisting of 5 to 60 mol %, in particular 15 to 50 mol %, of isophthalic acid.
An important feature is that thermal bonding is performed via an adhesive layer containing seeds. First, the present invention provides that the above-mentioned specific copolyester adhesive is effective against both cleave-resistant resins consisting of ester repeating units such as polyethylene terephthalate, polybutylene terephthalate, and polycarbonate, and olefin-vinyl alcohol copolymers. It utilizes the phenomenon of forming a strong adhesive bond by heating. The copolyester adhesive used in the present invention can be any copolyester provided that it contains the aforementioned amounts of terephthalic acid and isophthalic acid as dibasic acid components. This copolyester has the following formula In the formula, R ₁ is an aliphatic divalent hydrocarbon group,
R ₂ is a divalent hydrocarbon group, and 95 to 40 mol% of _{the total R 2 groups} are p-phenylene groups, and 5 to 60
The mole percent consists of repeating units represented by selected to be m-phenylene groups, and the copolyester may be used alone or in a blend of two or more. In addition, in this specification, the total dibasic acid component, in the case of a blend, refers to the total amount of dibasic acid components of all copolyesters in the blend. In the present invention, the glycol component, namely HO-
Examples of R ₁ -OH include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, triethylene glycol, cyclohexanediol,
Xylene glycol, hexahydroxylylene glycol, etc. can be mentioned, and among these, ethylene glycol and 1,4-butanediol are preferred glycol components. In addition to these ethylene glycol and 1,4-butanediol, other glycol components are
It can be incorporated in amounts up to 40 mol%. In the present invention, the dibasic acid component, i.e., HOOC
As -R ₂ -COOH, the above-mentioned combination of terephthalic acid and isophthalic acid is used. Provided that the molar ratio of terephthalic acid and isophthalic acid is within the above range, the copolyester can contain dibasic acid components other than the above acid components, such as naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenylmethane dicarboxylic acid, Adipic acid, sebacic acid, maleic acid, fumaric acid, succinic acid, hexyhydroterephthalic acid, etc. may be contained in the ester repeat unit. These other dibasic acid components should be present in an amount of up to 50 mol% of the total dibasic acid components, especially 40
It should be present in an amount of no more than mol%. Examples of suitable copolyesters include, but are not limited to: Polyethylene terephthalate/isophthalate, polybutylene terephthalate/isophthalate, polyethylene/butylene terephthalate/isophthalate, polyethylene terephthalate/isophthalate/adipate, polyethylene/hexahydroxylylene terephthalate/isophthalate. Various copolyesters can also be used in the present invention in the form of blends; preferred blend copolyesters are blends containing polybutylene terephthalate/isophthalate and polyethylene terephthalate/isophthalate, generally 95: A weight ratio of 5 to 5:95, especially 90:
It is a blend containing in a weight ratio of 10 to 10:90. This copolyester blend is particularly suitable for the purpose of forming a high peel strength interlayer bond between a creep resistant resin layer and an olefin-vinyl alcohol copolymer layer. During the formation of this blend, that is, during melting, a transesterification reaction may occur between the two copolyesters, but even if such mutual reaction occurs, it does not affect the purpose of the present invention. It is also important that terephthalic acid and isophthalic acid are present within the above quantitative range in the copolyester used in the present invention. That is, the terephthalic acid component is related to thermal adhesion with a creep-resistant resin layer such as polyethylene terephthalate, and is also related to the mechanical strength and heat resistance of the copolyester itself as an adhesive. If it is lower than the above range, these properties will deteriorate. On the other hand, the isophthalic acid component is related to thermal adhesiveness with the olefin-vinyl alcohol copolymer layer, and further improves thermal adhesiveness by lowering the melting point of the copolyester, and improves the softness and flexibility of the copolyester. If this amount is less than the above range, these properties will still deteriorate. The copolyester used in the present invention should have a molecular weight sufficient to form a film, generally measured in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 60:40 at a temperature of 30°C.
It is desirable to have an intrinsic viscosity [η] of 0.04 to 0.28/g, particularly 0.05 to 0.18/g. Furthermore, this copolyester has excellent thermal bonding workability.
It is desirable to have a melting point of 80 to 280°C, particularly 90 to 240°C. The copolyesters mentioned above may be used alone or in combination.
Blends of more than one species can also be used, as well as other thermoplastic resins such as polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-
Blends of olefin resins such as butene-1 copolymer, ionically crosslinked olefin copolymer (ionomer), ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, acid-modified polyethylene, acid-modified polypropylene, etc. It can also be used in the form
Of course, these olefin resins
It is used in an amount not exceeding 50% by weight, especially not more than 30% by weight. The reason why the above-mentioned copolyesters exhibit strong thermal adhesion to both creep-resistant resins consisting of repeating ester units such as polyethylene terephthalate and olefin-vinyl alcohol copolymers is still not fully understood. I haven't reached it yet, but
The present inventors believe that the reason is as follows.
It is generally recognized that thermal adhesion at the interface between the two resins is greatly influenced by the differences in the chemical structures of the two resins, the occurrence of chemical bonds between the two resins, and the mixture of the two resins at the adhesive interface. Since the copolyester adhesive used in the present invention has p-oriented terephthalate repeating units, it can be strongly thermally bonded to similarly oriented creep-resistant resins such as polyethylene terephthalate, polybutylene terephthalate, or polycarbonate. It is recognized that In addition, since this copolyester has isophthalic acid ester repeating units, the copolyester polymer chain tends to take a bent structure, which increases the probability of forming hydrogen bonds with the olefin vinyl alcohol copolymer. It is recognized that the degree of hydrogen bonding that occurs has become extremely high. Furthermore, it is recognized that good mixing occurs between the resins of this copolyester and the olefin-vinyl alcohol copolymer during thermal bonding. Although the reason for this is not precisely known, it is believed to be closely related to the fact that the solubility indices of both resins are quite close. Here, the solubility index (Solubility Parameter,
Sp value) is, for example, Chapter 4 of "Polymer Handbook" edited by J. BRANDRUP et al. (Johm Wiley
& Sons, Inc., 1967), it is defined as the 1/2 power of the cohesive energy density (cal/cc). This solubility index is also closely related to the strength of hydrogen bonds in thermoplastic resins.
Thermoplastic polymers containing polar groups such as hydroxyl groups, amide groups, ester groups, nitrile groups, or chlorine atoms in the polymer main chain or side chain may be affected by the content and distribution state of these polar groups. , generally shows a high value of 9 or more. For example, the Sp value of polyethylene phthalate is
10.7, the Sp value of polybutylene terephthalate is
10.04, that of polycarbonate is 10.01, the Sp value of polybutylene terephthalate/isophthalate varies depending on the isophthalate content, but is generally in the range of 9.0 to 10.1, and that of ethylene-
The Sp value of vinyl alcohol copolymers varies depending on the ethylene content in the copolymer, but in general
The Sp value of this copolyester is in the range of 9.7 to 11.6, which is higher than that of polyethylene terephthalate, polybutylene terephthalate and polycarbonate
It can be seen that the Sp value is close to that of the olefin-vinyl alcohol copolymer. In addition, the solubility index (Sp value) of a copolymer can also be approximately determined as an arithmetic mean value from the Sp value of a homopolymer of each monomer constituting the copolymer.
That is, the Sp value of the n-component copolymer is calculated by the following formula: Sp ⁼ _o 〓 is the mole fraction of the repeating unit in the copolymer. It can be obtained approximately by This applies both to copolyesters and to olefin-vinyl alcohol copolymers. The laminated structure of the present invention is a film, a sheet, etc., especially when used as a container, from the viewpoint of preventing deformation due to pressure, etc., and from the viewpoint of mechanical strength and water resistance. It must have a transparent resin layer. This creep resistant resin has a temperature of 23°C and 7x
The sum of the initial elastic modulus (Eg) and delayed elastic modulus (E ₁ ) under a stress of 10 ⁷ dyne/cm ² is 1×10 ¹⁰ dyne/cm ² or more, and the steady flow viscosity (η∞) is 1 Those having rheological properties of at least ×10 ¹⁷ dyne/cm ² and a delay time (t _R ) of at most 6×10 ⁶ sec are advantageously used. Generally, when a stress S is applied to a viscoelastic material such as a thermoplastic polymer for a period of time t, when t is short, it behaves like a viscoelastic material, and as t increases, viscosity is affected in addition to elasticity. The system behaves viscoelastically, and viscous flow occurs where t is sufficiently large. These viscoelastic behaviors are explained by the above-mentioned Eg,
It can be expressed in a model by the characteristics of E ₁ , η∞, and t _R. When the molded container is used as a pressure-resistant container such as a carbonated beverage container or an aerosol container,
In addition to having excellent gas barrier properties, the material constituting the container wall is required to have appropriate hardness to withstand the pressure of the contents, and a combination of creep resistance and impact resistance. Among the viscoelastic properties mentioned above, the sum of the initial elastic modulus and delayed elastic modulus (Eg + E ₁ ) is related to the hardness of the container. Eg+ under the condition of 7×10 ⁷ dyne/cm ²
E ₁ value is 1×10 ¹⁰ dyne/cm ² or more, especially 2×
It is important that it is ¹⁰ dyne/cm ² or more. In addition, steady flow viscosity (η∞) and delay time (t _R ) are related to creep resistance, and in the present invention, from the standpoint of preventing creep, η∞ is 1×10 ¹⁷ Poise
As mentioned above, it is particularly important that t R be 5×10 ¹⁷ Poise or more and t _R be 6×10 ⁶ sec or less, especially 3×10 ⁶ sec or less. Regarding these properties, among the various thermoplastic resins, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polycarbonate (PC) are ranked in order of superiority, and these resins are particularly suitable for the purpose of the present invention. It is something that Further, these resins can be used in a blend with each other, and blends with other thermoplastic resins can also be used within a range that does not impair creep resistance. The above-mentioned polyesters can be used in the form of so-called homopolymers, but it is permissible to contain small amounts of comonomers in the main chain in order to improve properties during thermoforming, e.g. to reduce drawdown during molding. Modified PET, modified PBT, etc. containing a small amount of hexahydroxylylene glycol as a glycol component are used for the purposes of the present invention in order to improve properties. Polycarbonate is a polycarbonate ester derived from various dihydroxy compounds and phosgene, such as poly-p-xylylene glycol biscarbonate, poly-dioxydiphenyl-methane carbonate, poly-
Examples include dioxydiphenyl-2,2-propane carbonate and poly-dioxydiphenyl-1,1-ethane carbonate. These creep resistant resins should generally have sufficient molecular weight to form a film. On the other hand, as the olefin-vinyl alcohol copolymer, a copolymer having an olefin unit such as ethylene-propylene and a vinyl alcohol unit obtained by saponifying a vinyl ester unit such as vinyl acetate is used. From the viewpoint of gas barrier properties and moisture resistance, the vinyl alcohol copolymer should contain 40 to 80 mol%, especially 50 to 75 mol, of vinyl alcohol units, and the content of residual vinyl ester units should be 4 mol. %, in particular 1 mol % or less. The olefin-vinyl alcohol copolymer desirably has a viscosity of 0.07 to 0.17 dl/g, for example, as measured at 30°C in a mixed solvent of phenol:water in a weight ratio of 85:15. In addition to being able to use this olefin-vinyl alcohol copolymer alone as a gas barrier layer, this olefin-vinyl alcohol copolymer can also be used as a gas barrier layer in the form of a blend with other thermoplastic resins. Can be done. A suitable example of this blend is olefin-vinyl alcohol copolymer and polyamide in a ratio of 95:5 to 95:5.
Mention may be made of blends containing a weight ratio of 40:60, in particular a weight ratio of 90:10 to 50:50. As described in Japanese Patent Publication No. 57-42493, this blend exhibits a small oxygen permeability coefficient almost comparable to that of olefin-vinyl alcohol copolymer, but also has excellent stretching workability. It is advantageously used in the production of blow-molded containers and sheet-molded containers by stretching. In the laminated structure of the present invention, any arrangement can be used as long as the copolyester adhesive (CAP) is interposed between the creep-resistant resin (PT) and the olefin-vinyl alcohol copolymer layer (PEVA). . For example, the illustrated PT/CAP/PEVA/
In addition to the symmetrical five-layer configuration of CAP/PT, PT/CAP/
Any layer structure can be adopted, such as a three-layer structure of PEVA; a four-layer structure of PT/CAP/PEVA/CAP. In addition, scraps obtained by pulverizing defective products during container molding may be used by mixing them with creep-resistant resin, but a laminated structure with a new scrap layer (SR), such as SR/PT/CAP/ PEVA/
CAP/PT or PT/SR/CAP/PEVA/
6-layer configuration of CAP/PT, SR/PT/CAP/
PEVA/CAP/PT/SR or PT/SR/
A seven-layer configuration of CAP/PEVA/CAP/SR/PT can be adopted. The thickness of these three layers can be changed arbitrarily, but
In order to obtain the optimum combination of gas barrier properties, impact resistance, rigidity, and delamination resistance mentioned above, it is preferable that the PT layer is the thickest, and the CAP layer and the PEVA layer are thinner than this. Specifically, the thickness ratio of each layer is preferably in the range of PT:PEVA=200:1 to 5:1 and PEVA:CAP=10:1 to 1:2. The laminate may also have a thickness of 50 to 3000 microns, especially 100 to 2000 microns, in the form of the final container.
It is preferable to have a thickness of microns. Formation of the laminate is preferably carried out by multilayer coextrusion. According to this multilayer coextrusion, since both resins are well mixed at the adhesive interface between the two resins, a laminated structure with particularly excellent adhesive strength can be obtained. For multilayer coextrusion, creep-resistant resin,
After melt-kneading the gas barrier resin and copolyester adhesive in their respective extruders, the copolyester adhesive is interposed between the creep-resistant resin layer and the gas barrier resin layer through a multilayer die. It is extruded and formed into shapes such as films, sheets, pipes for bottles, preforms for bolts, etc. In the case of bottle preforms, the multi-layer co-extruded molten resin parison is pre-blow molded in a mold, or the multi-layer co-extruded pipe is cooled and cut to a certain size, and then the upper and lower ends of the pipe are cut into pieces. It is obtained by reheating the parts and molding the mouth thread part and the bottom part by means such as compression molding. The laminate can be formed by a method called sandwich lamination or extrusion coating. For example, a thin film of copolyester adhesive is extruded between a preformed film of creep-resistant resin such as polyethylene terephthalate and a film of olefin-vinyl alcohol copolymer, and these are heated if necessary. A laminate can be manufactured by pressure bonding. Alternatively, an olefin-vinyl alcohol copolymer is coextruded as an intermediate layer and a copolyester adhesive is used as both inner and outer layers between two creep-resistant resin films, and this co-extruded layer is replaced with a creep-resistant resin film. A laminated structure can also be obtained by pressing with a film in the form of a sandwich. Furthermore, there is a method of sequentially extrusion coating a copolyester adhesive and an olefin-vinyl alcohol copolymer on the surface of a creep-resistant resin film, and a method of hot-pressing three types of pre-formed films in the above-described lamination sequence. Alternatively, a method such as hot rolling may be adopted. Furthermore, when molding a multilayer preform, a copolyester adhesive and an olefin resin are applied to the inner or outer surface of a bottomed preform made of a creep-resistant resin such as polyethylene terephthalate.
A method of manufacturing a multilayer preform by successively injecting vinyl alcohol copolymers may also be adopted. 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 carried out by means known per se, except that the multilayer preform described above is used. First, the multilayer preform is preheated to a stretching temperature prior to stretch blowing. This stretching temperature is a temperature lower than the crystallization temperature of the polyester used and at which the multilayer preform can be stretched, and specifically, a temperature of 80 to 130°C, particularly 90 to 110°C is used. . Stretch blow molding of the preheated preform can be performed 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 by circumferential expansion of the container under fluid injection at a relatively high pressure. In the latter case, stretching in the circumferential direction and stretching in the axial direction are simultaneously performed 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 to 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
It is desirable to set it to 1.7 to 4.0 times (circumferential direction). In the body of the container formed by stretch blow molding in this way, the polyethylene terephthalate layer is molecularly oriented so that its density is in the range of 1.350 to 1.402 g/cc, providing the desired impact resistance and rigidity for bottle-shaped containers. , transparency, etc., and the presence of the olefin-vinyl alcohol copolymer layer provides excellent barrier properties against gases such as oxygen, nitrogen, carbon dioxide, and fragrance. Excellent interlayer adhesion is maintained due to the presence of the agent. In addition, in the case of a sheet-formed container, the above-mentioned multilayer film or multilayer sheet is preheated to the above-mentioned stretching temperature, and this heated film etc. 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. Example 1 Table 1 shows the composition molar ratio of the adhesive composition used in this example. The adhesive composition was obtained by the following method. A predetermined amount of dimethyl terephthalate (hereinafter referred to as DMT),
Phthalate esters such as dimethyl isophthalate (hereinafter referred to as DMI) and ethylene glycol (hereinafter referred to as
EG), 1,4-butanediol (hereinafter referred to as BD), and a catalyst were placed in a four-necked flask, and transesterification was carried out with stirring. The reaction is
Starting from 165℃, the temperature was increased to 200℃ at a rate of 0.5℃/min, and the theoretical amount of methanol was reached 85 minutes after the start of the reaction.
90% was collected. Next, a predetermined amount of trimethyl phosphate (hereinafter referred to as TMPA) was added at 200°C, and the
Allowed to react for minutes. Next, esterification was carried out while raising the temperature to 240°C for 30 minutes, and then the temperature was raised to 265°C and polymerization was carried out at 0.1 mmHg for 4 to 6 hours. The final composition of the obtained polymer is proton
Analyzed by NMR and gas chromatography. Table 1 shows the composition ratios in mole % according to the component results. Next, 24 types of adhesive compositions (CAP-1,
CAP-2, CAP-3, CAP-4, CAP-5,
CAP-6, CAP-7, CAP-8, CAP-9,
CAP-10, CAP-11, CAP-12, CAP-13,
CAP-14, CAP-15, CAP-16, CAP-17,
CAP-18, CAP-19, CAP-20, CAP-21,
CAP-22, CAP-23, and CAP-24) were formed into a film using a hot press, and then rapidly cooled in water to prepare samples. The produced adhesive film is then transformed into a biaxially stretched polyethylene terephthalate film (hereinafter referred to as
PET-F), biaxially oriented polybutylene terephthalate film (hereinafter referred to as PBT-F), polycarbonate film (hereinafter referred to as PC-F), and has a vinyl alcohol content of 56 mol%, an ethylene content of 44 mol%, and an ethyl acetate residue. The group is 0.4 mol% ethylene-
Vinyl alcohol copolymer film (PEVA)
-F) and laminated films were prepared using a hot press. The laminated film production method involves laminating 24 types of adhesive films with PET-F, PBT-F, PC-F, and PEVA-F, holding them in a hot press at 270°C for 120 seconds under no pressure, and then applying a pressure of 5 kg/ ^cm2. Press,
This is a method of creating a laminated film by holding it for 60 seconds. The obtained laminated film was cut to a width of 10 mm and subjected to a T-peel peel test using a tensile tester at a tensile speed of 100 mm/min. The results are shown in Table 2.

【table】

【table】

【table】

[Table] Example 2 Polyester adhesive resin of Example 1, CAP
-6 (adhesive) and CAP-16 (adhesive) weight ratio
10:90 (hereinafter CAP-6: CAP-16), 20:80,
30:70, 40:60, 50:50, 60:40, 70:30, 80:
20 and melt-mixed at a ratio of 90:10 to obtain an adhesive resin composition. These compositions were prepared in the same manner as in Example 1 to obtain a thickness of
A film of 200 to 300μ was produced. The obtained films were CAP−25, CAP−26, and CAP−, respectively.
27, CAP−28, CAP−29, CAP−30, CAP−
31, CAP-32, and CAP-33). next,
PET-F and the nine types of adhesive films described above were laminated, held in a hot press at 270°C for 120 seconds under no pressure, and then pressed at a pressure of 5 kg/cm ² to obtain a laminated film. This was cut to a width of 10 mm, and a T-peel peel test was performed using a tensile tester at a tensile speed of 100 mm/min. In the same manner, the adhesive strengths of PBT-F, PC-F, and PEVA-F with the above nine types of adhesives were determined. The results are shown in Table 3.

【table】

[Table] Example 3 Weight ratio of phenol/tetrachloroethane
The intrinsic viscosity at 30℃ in a 550/50 mixed solvent is
0.087/g polyethylene terephthalate resin (PET) is used as the innermost layer resin, the vinyl alcohol content is 56 mol%, and the residual vinyl ester concentration is
Ethylene-vinyl alcohol copolymer resin (PEVA) with a melting point of 162°C and 0.5 mol% was used as the intermediate layer resin, and the adhesive used in Example 2 (CAP-
33) as the adhesive layer resin, an extruder for the outermost layer with a built-in full-flight screw with a diameter of 65 mm and an effective length of 1430 mm, and an extruder with a built-in full-flight screw with a diameter of 38 mm and an effective length of 950 mm. Extruder for middle layer, diameter 40mm,
PET/CAP-33/PEVA/CAP-33/PET/CAP-33/PEVA/CAP-33/
A symmetrical 5-layer PET pipe is melt-extruded and pre-blow molded in a split mold, with an inner diameter of 27.7 mm and a length of
A bottomed preform with a diameter of 138 mm and an average wall thickness of 3.5 mm was molded. Furthermore, this preform's PET/CAP-
The extrusion conditions were set so that the composition ratio of 33/PEVA was 91:4:5 by weight. This preform with a bottom is heated with an infrared heater, and the temperature of the preform reaches a maximum of 108℃.
After setting the minimum temperature to 98℃, it was stretch-blow molded using a sequential biaxial stretch blow molding method so that the axial stretch ratio was 2.0 times and the circumferential direction stretch ratio was 3.0 times, and the average wall thickness was 0.40 mm.Contents Product is 1040c.c., bolt weight is 36g
A bottle (B-1) was manufactured. As a comparative example, a bottomed preform with the same dimensions as above was molded using only polyethylene terephthalate (PET), and then a biaxially stretched blow bottle (B-2) with the same dimensions was manufactured in the same manner as above. Table 4 shows the transparency (haze) of the above two types of bottles,
The observation results of oxygen permeability, drop impact strength, and delamination phenomenon by drop test are shown.

[Table] Example 4 For the copolyester polymer (CAP-6) used in Example 1, the melting point was 160℃, the density was 0.91g/cc, and the melt index (210℃, 2160g load) was 1.5g/cc.
CAP-6-M is a resin mixture obtained by melt-mixing maleic anhydride-modified polypropylene with a maleic anhydride content of 0.6% by weight at a weight ratio of 80:20 for 10 minutes, and has a melting point of 255℃ and an intrinsic viscosity of 0.065/g. Polyethylene terephthalate and melt index
CAP-6-I is a resin mixture in which sodium salt modified ionomer with a density of 0.91 g/cc is melted and mixed at a weight ratio of 10:80:10, with a melting point of 96°C and a density of 0.93 g/cc. A resin mixture obtained by melt-mixing an ethylene-vinyl acetate copolymer with a vinyl acetate content of 11% by weight at a weight ratio of 80:20 was designated as CAP-6-P, and the above three resin mixtures were prepared in the same manner as in Example 1. Three types of films were made for each method. next,
These three types of films and those used in Example 1
PET-F, PBT-F, PC-F and PEVA-F
The film was made into a laminated film in the same manner as in Example 1, and a peel test was conducted in the same manner as in Example 1. The results are shown in Table 5.

【table】 [Brief explanation of drawings]

FIG. 1 is a side sectional view showing an example of a bottle-shaped plastic structure, and FIG. 2 is a sectional view showing an enlarged cross section of FIG. 1. 1 is the torso, 2 is the bottom, 3 is the shoulder, 4 is the neck, 5
6 is a polyester inner surface layer, 6 is a polyester outer surface layer, 7 is a gas barrier layer, and 8 and 9 are copolyester-containing adhesive layers, respectively.

Claims (1)

[Scope of Claims] 1. A creep-resistant resin layer mainly containing ester repeating units and a gas-barrier resin layer containing an olefin-vinyl alcohol copolymer are combined in such a manner that 95 to 40 mol% of the total dibasic acid component is 5 to terephthalic acid
A plastic laminate structure, characterized in that it is laminated via an adhesive layer containing a thermoplastic copolyester or copolyester composition containing 60 mol% of isophthalic acid. 2. A structure according to claim 1, wherein the thermoplastic copolyester is polybutylene terephthalate/isophthalate. 3. A structure according to claim 1, wherein the thermoplastic copolyester is polyethylene terephthalate/isophthalate. 4. The structure of claim 1, wherein the thermoplastic copolyester composition is a mixture of polybutylene terephthalate/isophthalate and polyethylene terephthalate/isophthalate. 5. A structure according to claim 1, wherein the creep-resistant resin is a polyester mainly composed of ethylene terephthalate repeating units. 6. A structure according to claim 1, wherein the creep-resistant resin is a polyester mainly composed of butylene terephthalate repeating units. 7. The structure according to claim 1, wherein the creep-resistant resin is polycarbonate. 8 Olefin-vinyl alcohol copolymer is a saponified copolymer obtained by saponifying an ethylene-vinyl acetate copolymer with an ethylene content of 20 to 60 mol% so that the saponification degree is 95% or more. A structure according to claim 1. 9 A creep-resistant resin layer mainly composed of ester repeating units and a gas barrier resin layer containing an olefin-vinyl alcohol copolymer are combined with terephthalic acid in an amount of 95 to 40 mol% of the total dibasic acid component.
A multilayer plastic container for sealing, characterized in that it consists of a laminate laminated via an adhesive layer containing a thermoplastic copolyester or copolyester composition comprising 60 mol% of isophthalic acid.