JPH0214180B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a multilayer biaxially stretched molded container, and more particularly to a method for manufacturing a multilayered biaxially stretched molded container that has an excellent combination of gas barrier properties and interlayer adhesiveness. It is known that biaxial stretching of thermoplastic plastics that can be oriented by stretching, such as polypropylene and polyethylene terephthalate, improves appearance such as transparency, mechanical properties such as rigidity, dimensional stability, etc. Axial stretching has also been used for a long time to form containers. It has also been used to mold containers for a long time. In manufacturing this container, the above-mentioned thermoplastic plastic is formed into a bottomless or bottomed cylindrical body, that is, a parison, by extrusion molding or injection molding, and the parison is stretched in the axial direction and the parison is stretched in the circumferential direction. By performing the operation of inflating by blowing fluid simultaneously or sequentially, a molded container having a container wall with molecules oriented in biaxial directions is formed. Although this biaxially stretched molded container is excellent in the transparency, rigidity, impact resistance, dimensional stability, etc. described above, it is still not fully satisfactory in terms of gas barrier properties. For example, biaxially stretchable plastics such as polypropylene and polyethylene terephthalate have lower oxygen permeability coefficients than high gas barrier resins such as saponified ethylene-vinyl acetate copolymers and vinylidene chloride resins even after stretching. On the other hand, there is a problem in that high gas barrier resins are generally difficult to biaxially stretch. In order to improve the gas barrier properties, particularly the oxygen barrier properties, of a biaxially stretched molded container, it is already known to combine an oxygen barrier resin with the above-mentioned oriented thermoplastic to form a multilayer biaxially stretched molded container. For example, Japanese Unexamined Patent Publication No. 53-1971 proposed by the present inventors, etc.
Publication No. 21674 discloses that the melting point or softening point of the oriented resin and the melting point or softening point of the oxygen barrier resin are selected so that the difference between them is within a certain range, and the molding is performed at a specific temperature. It is disclosed that the delamination resistance can be improved by this. However, in this proposal, the combination of resins that can be used is limited by the melting point, and furthermore, the oxygen barrier resin used must be melt-extrudable together with the alignment resin. In addition, when stretch-molding a multilayer parison, stress and strain are likely to occur at the interlayer interface between both resin layers, and even though the molded container described above exhibits relatively good peel strength immediately after manufacture, it is susceptible to drop impact. It is observed that when is repeatedly applied, the peel strength decreases rapidly. The present inventors applied a solution or emulsion of an adhesive and gas barrier resin to a preform of an oriented thermoplastic resin, controlled the temperature of the coated surface, and applied the oriented thermoplastic resin to the coated surface. is further applied by injection to form a multilayer parison, and when this multilayer parison is subjected to biaxial stretching blow molding, the gas barrier properties are significantly improved while applying the gas barrier resin in the form of a solution or emulsion. It has also been found that a multilayer biaxially stretched molded container having high gas barrier properties and substantially no tendency to decrease in peel strength even when subjected to repeated drop impacts can be obtained. That is, an object of the present invention is to provide a method for manufacturing a multilayer biaxially stretched molded container, which has an intermediate layer containing a gas barrier resin that cannot be thermoformed or is difficult to thermoform, and in which the humidity dependence of the gas barrier property is small. . Another object of the present invention is to produce a multilayer biaxially stretched molded container that has an excellent combination of gas barrier properties and interlayer adhesion properties, and in particular has a markedly improved tendency to decrease in peel strength when repeatedly subjected to impact. It is in providing the law. Another object of the present invention is to form a multilayer biaxially stretched resin having adhesive properties and gas barrier properties, and further comprising a resin applied as a solution or emulsion, especially a resin that cannot be thermoformed or is difficult to thermoform, as an intermediate layer. To provide a method for manufacturing containers. Still another object of the present invention is to provide a method for manufacturing a biaxially stretched molded container using a multilayer parison obtained by a combination of two stages of injection molding and a coating between them. According to the present invention, on one surface of a bottomed preform made of a thermoformable oriented thermoplastic polymer,
A step of applying and drying a solution or emulsion of a gas barrier resin having adhesive properties that cannot be thermoformed or difficult to thermoform, forming a coating of the gas barrier resin;
℃ and setting it in a secondary injection mold; and injecting a thermoformable oriented thermoplastic polymer onto the coated surface of the preform to form a bottomed multilayer parison. The multilayer parison is stretched in the axial direction and stretched in the circumferential direction by blowing under temperature conditions that cause molecular orientation of the thermoplastic polymer on at least one of the inner surface side and the outer surface side. A method for producing a multilayer biaxially stretched molded container characterized by the following features is provided. In FIG. 1 showing a multilayer biaxially stretched container 1 according to the present invention, this container has a mechanism (for example, screws, beads, etc.) for fastening the lid (not shown).
It consists of a mouth part 2 with a parison, a body wall part 3 connected to the mouth part, and a bottom wall part 4 connected to the body wall part, and this bottom wall part 4 has a seam 5 formed by pinching off the parison. It may be seamless or seamless. As can be seen from the cross-section in FIG. 1, the container wall comprises an inner surface layer 6 and an outer surface layer 7 each formed of a thermoformable oriented thermoplastic polymer, both surface layers. A distinctive feature of the present invention is that a resin layer 8, which has both adhesion and gas barrier properties and is applied as a solution or emulsion, is provided between layers 6 and 7. Resins with excellent gas barrier properties are generally polymers containing a high concentration of polar groups such as hydroxyl groups, halogen atoms, or nitrile groups, and these resins have strong hydrogen bonds and are difficult to melt. , even if it is possible to melt
Since the melting temperature and the thermal decomposition temperature are close to each other, there are many restrictions on molding, and in particular coextrusion with other oriented resins is accompanied by many difficulties. Thus, in conventional multilayer stretch-molded containers, ingredients such as saponified ethylene-vinyl acetate copolymers that improve thermoformability but degrade gas barrier properties are used as gas barrier resins (e.g., ethylene). ), or by blending a resin component that improves thermoformability, or by adding a plasticizer to make thermoforming possible. In contrast, the present invention uses a highly gas-barrier resin that cannot be thermoformed or is difficult to thermoform, for the bottomed multilayer parison. In other words, the present invention uses gas barrier resins that are excellent in gas barrier properties but cannot be thermoformed or are difficult to be thermoformed. By using it in the form of an emulsion, ie, a latex, it can be incorporated into a multilayer parison as an intermediate layer, regardless of the thermoforming temperature of the oriented resin, and the gas barrier properties can be further improved. It should be noted here that an important problem that arises when applying a gas barrier resin as a solution or emulsion is that the resin layer formed may have poor gas barrier properties due to mechanical or physical reasons. This means that it is easy to get injured. For example, in a gas barrier resin layer applied in the form of emulsion particles, gaps between the particles tend to remain, and these gaps become gas passages and the original gas barrier properties are lost. Furthermore, when coating with such a liquid, pinholes and the like are generally likely to occur, which also causes a decrease in gas barrier properties. On the other hand, according to the present invention, after coating a gas barrier resin as a solution or emulsion on a bottomed oriented resin preform and drying, the coated preform is heated to a temperature of 40 to 70°C. By adjusting, the above-mentioned interparticle gaps disappear, and the gas barrier resin is uniformly and densely applied around the primary injection alignment resin. That is, it is important to control the temperature of the coated preform at 40°C to 70°C. By controlling the temperature of the gas barrier resin and the coating preform to a temperature range of 40 to 70°C and setting it in the secondary injection mold, cooling of the polymer within the mold is possible during the secondary injection of the thermoplastic polymer. In order to improve the spreading of the polymer to the surface coated with gas barrier resin, and when the temperature is higher than 70°C, the gas barrier coating resin that has been carefully formed is subjected to secondary injection. There is a tendency for the polymer to be softened and scraped off, making it impossible to obtain the desired gas barrier properties. As shown in Examples 1 to 4, Tables 2 and 3 below, if the temperature of the coated preform was not controlled, the coverage of the secondary injection resin to the coating film was insufficient (100%). 100% coverage can be obtained when the temperature of the coated preform is controlled between 40°C and 70°C, whereas a shot mold is generated. If the temperature of the coated preform is adjusted to a temperature higher than 70°C, for example 80°C, the coating film may be scraped or doubled during the secondary injection of the resin, and when this multilayer parison is stretch-blow molded, Gas barrier properties deteriorate due to paint film breakage, but setting the temperature range between 40℃ and 70℃ prevents coating film scraping during secondary injection, resulting in excellent gas barrier properties. A stretch blow molded article is obtained. In the multilayer biaxially stretched molded container according to the present invention, the oxygen barrier resin layer 8 itself is firmly adhered to the inner and outer surface layers, and this adhesive strength (peel strength)
It has the additional advantage that it has a significantly lower tendency to deteriorate even after repeated impacts. That is,
It has already been mentioned above that when a multilayer parison formed by coextrusion is subjected to stretch blow molding, stress and strain tend to concentrate between the layers, which is a major cause of a decrease in adhesive strength. In contrast, in the present invention, the oxygen barrier resin applied as the intermediate layer is applied in the form of a solution or emulsion, and its complete film formation occurs during stretch molding, so it also acts as an adhesive. It is believed that the barrier resin that does this will have less internal strain. Thus, according to the present invention, not only can a multilayer container with excellent interlayer adhesion immediately after production be obtained, but also a multilayer container whose peel strength does not deteriorate even when subjected to repeated drop impacts. In the present invention, at least one, preferably both, of the inner surface layer 6 and outer surface layer 7 of the oriented resin,
Although the molecules are significantly oriented in the plane direction, that is, in both the axial direction and the circumferential direction of the container due to stretch blow molding, the intermediate layer 8 is mostly unoriented in many cases. The thickness of the intermediate layer 8 is very thin due to the fact that it is applied in the form of a solution or emulsion and is subsequently stretched and is generally in the range from 3 to 30 microns, in particular from 5 to 15 microns. On the other hand, the thicknesses of the inner and outer surface layers 6 and 7 are preferably in the range of 500 to 40 microns, particularly 250 to 60 microns, although they vary depending on the type of resin and the intended use. In the present invention, the gas barrier resin includes a resin that cannot be thermoformed or is difficult to thermoform and has both gas barrier properties and adhesive properties, particularly a resin having a hydroxyl group, a halogen atom (chlorine atom), or a nitrile group. used. A suitable example is: (1) Hydroxyl group-containing polymer polyvinyl alcohol, partially acetalized polyvinyl alcohol, partially saponified polyvinyl acetate, partially saponified partially acetalized polyvinyl acetate, partially crosslinked polyvinyl alcohol, unsaturated carboxylic acid grafted polyvinyl alcohol; unsaturated carboxylic acid Water-soluble polysaccharide polymers such as grafted starch, unsaturated carboxylic acid grafted dextrin, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, and cyanoethylated starch; hydroxyl group-containing acrylic resins such as hydroxyethyl acrylate/ethyl acrylate copolymer, etc. (2) Halogen-containing polymers Polyvinylidene chloride, polyvinyl chloride, vinyl chloride/vinylidene chloride copolymer, vinyl chloride/vinyl acetate copolymer, etc. (3) Nitrile group-containing polymer polyacrylonitrile, acrylonitrile/
Butadiene copolymer, acrylonitrile/styrene copolymer, acrylonitrile/methyl methacrylate copolymer, etc. It should be understood that the polymers exemplified above are for illustrative purposes only and that many other copolymers may be used. The gas barrier resin suitable for use in the present invention is a polymer containing a polar group selected from the group consisting of a hydroxyl group, a halogen atom, and a nitrile group at a concentration of 120 to 1400 meq (milliquibanlent) per 100 g of the polymer. It is.
These polymers also have excellent adhesive properties because they contain a large amount of polar groups. These resins can be used alone or in combination of two or more. Furthermore, for the purpose of enhancing adhesive strength, resins having other functional groups such as carboxymethyl cellulose and polyacrylate, such as carboxyl groups and carboxylic acid ester groups, can be blended in an amount of 50% by weight or less based on the resin. . However, the inclusion of plasticizers that reduce gas barrier properties should be avoided. As a thermoformable oriented thermoplastic polymer,
Anything that satisfies this requirement is fine.
Suitable examples include poloolefins such as polypropylene, polybutene-1, and polystyrene; poloesters such as polyethylene terephthalate; polyamides such as nylon 6, nylon 6, 6; plasticized polyvinyl chloride; plasticized nitrile polymers; Methacrylate; polycarbonate, etc. can be mentioned. The molecular weight of these polymers may be within the film-forming range. The inner and outer surface layers constituting the container may be made of the same resin or different ones, and it is a significant advantage of the present invention that various resin combinations can be made by considering only the adhesiveness of the intermediate layer resin used. The steps of the method of the present invention will be explained using FIG. A thermoplastic resin is injected from an inner layer injection machine 12 into an inner layer injection mold 13 to form a bottomed primary molded product 11. After holding the neck part of the primary molded product 11 with a neck holder and transporting it to the coating pot 14 for the next step and immersing it in the coating pot 14 to apply the coating agent to the surface of the primary molded product, Drying section 1
At step 6, the solvent of the coating solution or the water in the latex is removed by drying, and the temperature of the coated molded article 15 is adjusted by heating or cooling at a temperature adjusting section 17. After drying the coated resin layer, the coated molded product adjusted to a temperature of 40 to 70°C is subjected to second stage injection molding to form a multilayer parison. Coated molded product 1 sent from delivery section 18
5 is held by a holding chuck 19 and set in an injection mold 21 for outer layer, and resin is injected onto the outer surface of the coated molding 15 from an injection machine 20 for outer layer to form a multilayer parison 22. The molded multilayer parison 22 is heated in a heating pot 23 to a temperature at which the inner layer resin or outer layer resin can be stretched, and then a multilayer stretch molded container is molded in the next stretch blow molding section 24, thereby producing a molded multilayer stretch molded container. are discharged from a take-out section 25 consisting of a conveyor or the like and guided to the next capping process and boxing process. In the present invention, it is also important to use a bottomed primary molded product of an oriented resin, and to coat the surface of this primary molded product with a gas barrier resin. Conventionally, it has already been possible to form bolts by stretch-blowing a multi-layered pipe in which a polyvinyl alcohol (PVA) coating is formed on the surface of a polyester pipe, and a moisture-resistant resin coating is provided on top of this coating if necessary. It is known (Japanese Unexamined Patent Publication No. 117565/1983).
However, stretch blowing using this multilayered pipe provides a significant improvement in gas barrier properties. Moreover, by carrying out stretch hollow molding in the form of a bottomed multilayer parison, axial stretching and circumferential blow stretching are performed in a well-balanced manner, and the occurrence of breakage or cracks in the intermediate bath galactic resin layer is also prevented. be. Oxygen barrier resin coating can be applied by dipping,
It can be applied by spray painting, antistatic painting, roll coating, brush painting, etc. The concentration of the resin liquid generally ranges from 20 to 60% by weight as resin solids, and the viscosity may range from 100 to 10,000 centipoise. As the solvent, water, an organic solvent, or a combination thereof is used. In order to avoid an adverse effect on the alignment resin, it is preferable to use water as the solvent. In the case of a water-insoluble resin, an emulsion, i.e. Preferably used in latex form. Axial stretching and circumferential expansion of the multilayer parison
The process is carried out at a temperature at which effective molecular orientation of the alignment resin occurs. These stretch forming temperatures and stretching ratios are also well known per se, and the present invention is also carried out under well known conditions. In the present invention, the in-plane orientation coefficient (l+m) is
By giving the inner and outer surface layer resins a molecular orientation of 0.3 or more, particularly 0.4 or more, satisfactory results can be obtained in terms of transparency, rigidity, and impact resistance. The invention is illustrated by the following example. Example 1 Length 110m/m, outer diameter 25φ, wall thickness 1.5m/m
A primary molded product of polyester resin (intrinsic viscosity 0.7) was injection molded, and the primary molded product was cooled to about 80°C and immersed in an aqueous solution of Poval (Kuraray 117) at 50°C. Dry with hot air and adjust the temperature of the primary molded product to 50 to 70℃ to form the next outer layer resin, and inject polyester copolymer (manufactured by PET.G Kodatsu Co., Ltd.) into the outer layer using an injection molding machine for the outer layer. Then, it was heated to 100°C, stretched 2.0 times vertically using a stretching rod, and then blow molded to obtain a multilayer biaxially stretched 500 c.c. container. The average wall thickness of each layer of the resulting container is
300μ, 10μ, 280μ, the degree of orientation of the inner and outer layers is l
= 0.17, m = 0.35, and the outer layer had l = 0.20, m = 0.40. The oxygen gas permeability of this container is 1.7cc/day・
ATM, 37℃, adhesive strength between each layer is 1.1Kg/15m/m,
Peeling strength after 10 repeated drops is 1.0Kg/15m/
The container had a width of m width, a transparency value of 2.1% in terms of haze value, was resistant to surface scratches, and had good appearance and storage stability. For comparison, a container of the same thickness without a solution-like intermediate layer was molded with an oxygen permeability of 55c.c./day・atm・37℃, interlayer adhesion strength of 0.05Kg/15m/m, and peeling after repeated dropping 10 times. The strength was 0.01Kg/15m/m width. In addition, only the temperature control conditions were changed, and the temperature control temperature of the primary molded product was set to 15 to 20°C (Sample No. 1-A in Tables 1 and 2) and 80°C (Sample No. 1).
-C) was used as a comparative example, and the molded state of the preform and the molded product were evaluated. The results are shown in Tables 1 and 2. Example 2 Length 110m/m, outer diameter 25φ, wall thickness 1.5m/m
polymethyl methacrylate (PMMA, MI=
The primary molded product from 2) was injection molded, immersed in a solution of polysaccharide water-soluble polymer Pullulan R Hayashihara Biological Research Institute at 30°C, and dried with hot air at 98°C. Next, adjust the temperature of the molded product to 40 to 50℃, and use the injection molding machine for the outer layer to make polystyrene (MI=
6) was injected into the outer layer, heated to 120°C, stretched 1.8 times vertically using a stretching rod, and blow molded to obtain a multilayer biaxially stretched 500 c.c. container. The average wall thickness of each layer of the resulting container is
320μ, 8μ, 300μ, the degree of orientation of the inner and outer layers is l
= 0.15, m = 0.35, and the outer layer had l = 0.28, m = 0.41. The oxygen gas permeability of this container is 9.5cc/day・
ATM/37℃, adhesive strength between each layer is 0.9Kg/15m/m,
Peeling strength after 10 repeated drops is 0.85Kg/15m/
The container had a transparency of 1.8% in haze value, was resistant to surface scratches, and had good appearance and storage stability. For comparison, a container of the same thickness without a solution-like intermediate layer was molded with an oxygen permeability of 400c.c./day・atm・37℃, an interlayer adhesion strength of 0.01Kg/15m/m, and a peel strength after repeated dropping. However, it peeled off at the first try and could not be measured. In addition, only the temperature control conditions were changed, and the temperature control temperature of the primary molded product was set to 15 to 20 °C (Sample No. 2-A in Tables 1 and 2) and 80 °C (Sample No. 2).
-C) was used as a comparative example, and the molded state of the preform and the molded product were evaluated. The results are shown in Tables 1 and 2. Example 3 Length 150m/m, outer diameter 25φ, wall thickness 1.5m/m
The primary molding of PVC (P = 800, 3 parts MBS) is injection molded, and 90% vinylidene chloride and vinyl chloride are used at 30℃.
10% copolymer latex (55% solids, viscosity
150cps, particle size 0.2μ) solution, dry with hot air at 90℃, adjust the temperature of the primary molded product to 50 to 55℃ to form the next outer layer resin, and use the injection molding machine for the outer layer to form the above molded product. PVC was injected into the outer layer, heated to 105°C, stretched 1.3 times vertically with a stretching rod, and blow molded to obtain a multilayer biaxially stretched 500 c.c. container. The average wall thickness of the container obtained was 320μ, 8μ, and
310μ, the degree of orientation of the inner and outer layers is l = 0.25, m =
0.41, and the outer layer had l=0.29 and m=0.46. The oxygen gas permeability of this container is 2.5cc/day・
ATM, 37℃, adhesive strength between each layer is 2.5Kg/15m/m,
Peel strength after repeated dropping 10 times is 2.0Kg/15
m/m, transparency was 3.5% in Haze value, the container was hard to get scratches on the surface, and had good appearance and storage stability.
For comparison, a container of the same thickness without a solution-like intermediate layer had an oxygen permeability of 35c.c./day・atm・37℃,
The interlayer adhesive strength was 0.8 kg/15 m/m, and the peel strength after repeated dropping 10 times was 0.4 kg/15 m/m. In addition, only the temperature control conditions were changed, and the temperature control temperature of the primary molded product was set to 15 to 20°C (Sample No. 3-A in Tables 1 and 2) and 80°C (Sample No. 3).
-C) was used as a comparative example to evaluate the molding state of the preform and the molded product. The results are shown in Tables 1 and 2. Example 4 Length 110m/m, outer diameter 25φ, wall thickness 1.5m/m
A primary molded product of polyester resin (intrinsic viscosity 0.7) was injection molded, immersed in a solution of acrylonitrile latex (solid content 45%, viscosity 400 cps, particle size 0.3μ) at 50°C, and dried with hot air at 120°C. In order to provide the next outer layer resin, the temperature of the primary molded product was adjusted to 50 to 70℃, and acrylonitrile resin (manufactured by Monsanto, Burlex 210) was injected into the outer layer using an injection molding machine for the outer layer, and the temperature was heated to 102℃. The mixture was heated, stretched 1.8 times vertically using a stretching rod, and then blow molded to obtain a multilayer biaxially stretched 500 c.c. container. The average wall thickness of the container obtained was 300μ from the inner surface.
15μ and 250μ, the degree of orientation of the inner and outer layers is l = 0.17 for the inner layer,
m=0.35, and the outer layer had l=0.25 and m=0.39. The oxygen gas permeability of this container is 2.1cc/day・
ATM, 37℃, adhesive strength between each layer is 1.5Kg/15m/m,
Peeling strength after repeated dropping 10 times is 1.2Kg/15
m/m, transparency was 3.8% in Haze value, the container was hard to get scratches on the surface, and had good appearance and storage stability.
For comparison, a container of the same thickness without a solution-like intermediate layer had an oxygen permeability of 35c.c./day・atm・37℃,
The interlayer adhesive strength was 0.01 Kg/15 m/m, and the peel strength after repeated drops could not be measured because it peeled off the first time. In addition, only the temperature control conditions were changed, and the temperature control temperature of the primary molded product was set to 15 to 20°C (Sample No. 4-A in Tables 1 and 2) and 80°C (Sample No. 4).
-C) was used as a comparative example to evaluate the molding state of the preform and the molded product. The results are shown in Tables 1 and 2. Comparative example: length 110m/m, outer diameter 25φ, wall thickness 2.8m/m
A primary molded product of polyester resin (intrinsic viscosity 0.7) is injection molded, and the primary molded product cooled to about 80°C is immersed in an aqueous solution of Poval (Kuraray 177) at 50°C and heated with hot air at 100°C. After drying, it is stretched twice vertically using a stretching rod and then blow molded.
A container of 500 c.c. was obtained. The oxygen gas permeability of the obtained container was 4.5cc/
day・atm・37℃, interlayer adhesion strength is 0.05Kg/15
The container was m/m wide, easily scratched on the surface, and had poor storage stability. As a comparison for Examples 2 to 5, stretch-blown containers without an outer layer resin were made and evaluated. As in Comparative Example 1, only containers with poor oxygen gas permeability and adhesive strength were obtained.

[Table] *1…Polysaccharide

【table】 [Brief explanation of drawings]

FIG. 1 is a side sectional view of a multilayer biaxially stretched molded container according to the present invention, and FIG. 2 is a process diagram showing the production of a multilayer bottomed parison and the multilayered biaxially stretched molded container from the same, with reference numerals. 1 is a multilayer biaxially stretched molded container, 6 is an inner surface layer, 7 is an outer surface layer, 8 is a gas barrier/adhesive resin layer, 12 is an injection machine for the inner layer, 14 is a coating pot, 16 is a drying section, 20 2 shows an injection machine for the outer layer, 23 a heating pot, 24 a stretch blow molding section, and 22 a multilayer brief form.

Claims (1)

[Claims] 1 A solution or emulsion of a gas barrier resin having adhesive properties that cannot be thermoformed or is difficult to thermoform is applied to one surface of a bottomed preform made of a thermoformable oriented thermoplastic polymer and dried. a step of forming a gas barrier resin coating, a step of adjusting the obtained coated preform to a temperature of 40 to 70°C and setting it in a secondary injection mold, and a step of applying heat to the coated surface of the preform. injecting a moldable oriented thermoplastic polymer to form a bottomed multilayer parison;
Stretching the bottomed multilayer parison in the axial direction and circumferentially by blowing under temperature conditions that cause molecular orientation of the thermoplastic polymer on at least one of the inner surface side and the outer surface side. A method for producing a multilayer biaxially stretched container characterized by the following.