JP5814502B2 - Container and multilayer molded article excellent in sealability and flavor retention - Google Patents

Description

  The present invention relates to a container using a polyamide having excellent sealing properties as a sealant and excellent flavor retention of contents for the innermost layer, a method for producing the container, a multilayer molded body used for the container, and a method for producing the multilayer molded body. Regarding usage.

  As a gas barrier resin not containing chlorine, polyamide such as nylon 6 or polymetaxylylene adipamide (hereinafter sometimes abbreviated as N-MXD6) or ethylene vinyl copolymer (hereinafter sometimes abbreviated as EVOH) It has been known. Among them, N-MXD6 is suitable as a food packaging material because it has excellent oxygen barrier properties, particularly oxygen barrier properties after heat sterilization treatment such as boil and retort treatment, and high mechanical performance. They are used as multilayer bottles and blend bottles with polyethylene terephthalate (PET), as laminates with stretched films and base films such as polyolefins, and mixed with other materials such as nylon 6.

  Patent Document 1 includes a PP layer mainly composed of polypropylene, an adhesive layer made of an adhesive thermoplastic resin, and a polyamide obtained from a polycondensation reaction of metaxylylenediamine, an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid. A multilayer container in which a gas barrier layer as a main component is laminated is disclosed. In the multilayer container of polyolefin and polyamide as described in Patent Document 1, usually, polyamide is used as an intermediate layer, and as the innermost sealant layer, generally from the viewpoint of sealing properties and impact resistance, Polyolefin is used. However, since the polyolefin itself adsorbs the flavor of the content and is inferior in flavor retention, there is a problem that the storage period of the content that needs to retain the flavor for a long time is short.

  In addition, in the case of increasing the drop resistance when the container is dropped or in the case of a standing pouch, the thickness of the polyolefin or easy peel material used for the sealant layer may be increased to ensure self-sustainability. From the cross section, there is a problem that oxygen permeates and the gas barrier property deteriorates.

  On the other hand, a polyamide such as N-MXD6 is excellent as a barrier layer, chemical resistance, and flavor retention, so it is optimal as a barrier layer. However, since it has a high melting point, when used as a sealant layer on the inner surface, the sealing temperature is reduced. There is a problem that it is necessary to increase the sealing time, to increase the sealing time, to increase the sealing pressure or the mold pressure, and to have insufficient sealing performance. In addition, when N-MXD6 is used as a sealant layer after performing heat sterilization such as boiling or retort, there is also a problem that innermost layers of the seal portion are peeled off and cannot be formed as a container. Furthermore, since N-MXD6 is a rigid polyamide, when used as the innermost sealant layer, the impact resistance was insufficient.

  Patent Document 2 proposes to use amorphous polyamide as a sealant for the innermost layer of the container. However, these amorphous polyamides have poor barrier properties, chemical resistance, and flavor retention. Since it is sufficient and amorphous, it takes time to solidify after sealing the sealants, so there are problems such as filling the contents immediately after sealing the container or peeling off the seal during transportation. It was.

JP 2005-306419 A Japanese Patent Laid-Open No. 6-8975

  The present invention provides a container using a polyamide which is excellent in sealing properties as a sealant and excellent in flavor retention of contents as an innermost layer, a method for producing the container, a multilayer molded body used in the container, and the multilayer molded body It is an object of the present invention to provide a usage method.

As a result of intensive studies to solve the above problems, the present inventors have used the polyamide obtained by polycondensation of metaxylylenediamine and adipic acid and a specific copolymerization component as the innermost layer of the container. The present inventors have found that the problem can be solved and have reached the present invention.
That is, the present invention comprises (1) metaxylylenediamine and adipic acid and one or more copolymer components selected from diamines other than metaxylylenediamine, dicarboxylic acids other than adipic acid, aminocarboxylic acids, and lactams. A layer made of a molding material containing a polyamide obtained by polycondensation and containing a polyamide in which the content of structural units derived from the copolymer component in the polyamide is in the range of 2 to 6 mol% is most suitable. A container having an inner layer, wherein at least some innermost layers are fused together, (2) a method for producing the container, and (3) a multilayer molded body having a layer made of the molding material, The multilayer material used for the container which the layer which consists of the said molding material comprises the innermost layer of a container, and at least one part innermost layer fuse | melts, and (4) the usage method of the said multilayer molded object .

  According to the present invention, the polyamide used for the innermost layer of the container is excellent in sealability as a sealant, and therefore excellent in sealability and impact resistance after heat sterilization, and the chemical resistance of the contents and the flavor of the contents It is possible to provide a container having excellent retainability, a method for producing the container, a multilayer molded body used in the container, and a method for using the multilayer molded body.

It is sectional drawing which illustrated the direct blow bottle which is one form of the container of this invention. It is sectional drawing which illustrated the pouch which is one form of the container of this invention. It is sectional drawing which illustrated the cup-shaped container with a lid | cover which is one form of the container of this invention.

  The container of the present invention polycondenses metaxylylenediamine and adipic acid with at least one copolymer component selected from diamines other than metaxylylenediamine, dicarboxylic acids other than adipic acid, aminocarboxylic acids, and lactams. And the innermost layer has a layer made of a molding material containing polyamide in which the content of structural units derived from the copolymer component in the polyamide is in the range of 2 to 6 mol%. And at least some innermost layers are fused together.

  In the present invention, the diamine other than metaxylylenediamine used as a copolymerization component is 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl), cyclohexane, hexamethylenediamine, tetramethylenediamine. And aliphatic diamines such as pentamethylenediamine, octamethylenediamine, and nonamethylenediamine, and aromatic diamines such as paraxylylenediamine and paraphenylenediamine. The diamine is not limited to these, but an aliphatic amine is preferable from the viewpoint of ease of polymerization and control of crystallinity, and 1,3-bis (aminomethyl) cyclohexane or hexamethylene diamine is preferable. Is more preferable.

  In the present invention, dicarboxylic acids other than adipic acid used as a copolymerization component include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, etc. 20 linear aliphatic dicarboxylic acids, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and other naphthalenedicarboxylic acids, isophthalic acid, terephthalic acid, 4,4-biphenyldicarboxylic acid, 2,2-biphenyldicarboxylic acid An aromatic dicarboxylic acid such as biphenyl dicarboxylic acid such as an acid can be used. The dicarboxylic acid is not limited to these, but among them, it is preferable to use an aromatic dicarboxylic acid as a means for improving flavor retention.

In the present invention, the aminocarboxylic acid and lactam used as the copolymer component are preferably those having 6 or more carbon atoms. Α, ω-aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid, caprolactam And lactams such as laurolactam and undecaractam. The aminocarboxylic acid and lactam are not limited to these, but caprolactam is preferable from the viewpoint of suppressing the decrease in flavor retention.
Said copolymerization component may be used alone or in combination of two or more.
Among these copolymer components, aromatic dicarboxylic acid is preferable as a means for enhancing flavor retention, and in aromatic dicarboxylic acid, the liquid level in the polymerization vessel due to foaming is less likely to occur during polymerization. From the viewpoint of ease of polymerization such that the polymerization rate is not extremely slow, isophthalic acid is more preferable.

  In the present invention, the content of the structural unit derived from the copolymer component in the polyamide obtained by polycondensation of metaxylylenediamine, adipic acid, and the copolymer component is within the range of 2 to 6 mol%. is there. When the content of the structural unit derived from the copolymer component is 2 mol% or more, the crystallinity of the polyamide is lowered, and the crystallinity of the polyamide can be controlled preferably to 10% or less. As the melting point is lowered, the melting point is lowered, so that the sealing property as a sealant is excellent, and when it is 6 mol% or less, a certain degree of crystallinity is maintained, and thus the moldability and the barrier property are good. It is also easy to control the crystallinity of the polyamide to preferably 3% or more. From the above viewpoint, the content of the structural unit derived from the copolymer component is preferably 2 to 5 mol%.

  The polyamide used in the present invention is preferably produced by a melt polycondensation (melt polymerization) method. As the melt polycondensation method, for example, there is a method in which a nylon salt composed of a diamine component and a dicarboxylic acid component is heated in the presence of water under pressure, and polymerized in a molten state while removing added water and condensed water. It can also be produced by a method in which a diamine component is directly added to a molten dicarboxylic acid component and polycondensed. In this case, in order to keep the reaction system in a uniform liquid state, the diamine component is continuously added to the dicarboxylic acid component, and the reaction system is heated up so that the reaction temperature does not fall below the melting point of the generated oligoamide and polyamide. However, polycondensation proceeds.

  In the present invention, it is preferable to add a phosphorus atom-containing compound at the stage of melt polycondensation. If a phosphorus atom-containing compound is present in the system at this stage, yellowing of the resulting polyamide can be prevented, and further the amidation reaction rate can be accelerated, for example, polycondensation to a degree of polymerization that can be used as a packaging material. Since the heat history does not increase even if the process proceeds, gelation and coloring of the polyamide obtained can be prevented.

  Phosphorus atom-containing compounds added to the polycondensation system of polyamide include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, Ethyl phosphite, phenylphosphonite, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, ethyl phenylphosphonite, phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, phenylphosphonic acid Potassium, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate, phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyro phosphite Phosphoric acid etc. Among these, hypophosphorous acid metal salts such as sodium hypophosphite, potassium hypophosphite, lithium hypophosphite and the like are particularly effective in promoting the amidation reaction and are excellent in anti-coloring effect. It is preferably used, and sodium hypophosphite is particularly preferable. The phosphorus atom-containing compounds that can be used in the present invention are not limited to these compounds.

  The addition amount of the phosphorus atom-containing compound is preferably 50 to 400 ppm by mass, more preferably 60 to 350 ppm by mass, and even more preferably 70 to 300 ppm by mass in terms of the phosphorus atom concentration in the polyamide of the present invention. It is.

  In the polycondensation system of polyamide in the present invention, it is preferable to add an alkali metal compound in combination with a phosphorus atom-containing compound. In order to prevent coloring of the polyamide during polycondensation, it is necessary that a sufficient amount of the phosphorus atom-containing compound is present, but in some cases there is a risk of causing gelation of the polyamide, so that the amidation reaction rate is adjusted. In addition, it is preferable to coexist an alkali metal compound. As the alkali metal compound, an alkali metal hydroxide or an alkali metal acetate is preferable. Examples of the alkali metal compound that can be used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate, and the like. However, it can be used without being limited to these compounds.

  The polyamide obtained by melt polycondensation is once taken out, pelletized, and dried before use. In order to further increase the degree of polymerization, solid phase polymerization may be performed. As a heating device used in drying or solid phase polymerization, a continuous heating drying device, a rotary drum type heating device called a tumble dryer, a conical dryer, a rotary dryer or the like, and a rotary blade inside a nauta mixer are used. Although a conical heating apparatus provided with can be used suitably, a well-known method and apparatus can be used without being limited to these. Particularly in the case of solid-phase polymerization of polyamide, a batch heating apparatus is preferably used because it can seal the inside of the system and easily proceed with polycondensation in a state where oxygen that causes coloring is removed. It is done.

The polyamide obtained through the above-described steps is less colored and less gelled. In the present invention, among the polyamides obtained through the above-mentioned steps, the b ^* value in the color difference test of JIS-K-7105 is 3 The following are preferably used, particularly preferably 2 or less, and more preferably 1 or less. A polyamide having a b ^* value exceeding 3 is not preferable because a molded product obtained by post-processing has a yellowish color and its commercial value is low.

There are several indicators of the degree of polymerization of the polyamide used in the present invention, but the relative viscosity is generally used. In the polyamide used in the present invention, the preferred relative viscosity is 1.5 to 4.2, more preferably 1.7 to 4.0, and still more preferably 2.0 to 3.8. When the relative viscosity of the polyamide used in the present invention is 1.5 or more, the flowability of the melted polyamide is stabilized, and the appearance of the molded product is improved. When the relative viscosity of the polyamide is 4.2 or less, the melt viscosity of the polyamide is not too high and can be stably molded.
The relative viscosity here refers to a drop time (t) measured by dissolving 1 g of polyamide in 100 mL of 96 mass% sulfuric acid at 25 ° C. using a Canon Fenske viscometer, and 96 mass% sulfuric acid itself measured in the same manner. The ratio of the drop time (t0) of
Relative viscosity = t / t0

The polyamide used in the present invention may be blended with other thermoplastic resins such as polyamide and polyester as long as the effects of the present invention are not impaired.
Examples of other polyamides include nylon 4, nylon 6, nylon 10, nylon 11, nylon 12, nylon 4,6, nylon 6,6, nylon 6,10 and the like.

  Polyesters include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalene dicarboxylate resin, polyethylene-2,6- Naphthalene dicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4′-biphenyl dicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate (PBT) resin, and polybutylene-2,6 -A naphthalene dicarboxylate resin etc. are mentioned suitably. Among these, polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polybutylene terephthalate resin, and polyethylene-2,6-naphthalenedicarboxylate resin are more preferable.

  In order to suppress whitening after hot water treatment or dry heat treatment, a diamide compound and / or a diester compound can be used as necessary for the polyamide used in the present invention. A crystallization nucleating agent can also be used to impart transparency and increase crystallinity as well as to suppress whitening.

  The diamide compound is obtained from a fatty acid having 8 to 30 carbon atoms and a diamine having 2 to 10 carbon atoms. If the number of carbon atoms in the fatty acid is 8 or more and the number of carbon atoms in the diamine is 2 or more, an effect of preventing whitening can be expected, and if the number of carbon atoms in the fatty acid is 30 or less and the number of carbon atoms in the diamine is 10 or less, Uniform dispersion is good. From the above viewpoint, the diamide compound includes a diamide compound obtained from a diamine composed of a fatty acid having 8 to 30 carbon atoms and mainly ethylenediamine, and a diamide compound obtained from a fatty acid mainly composed of montanic acid and a diamine having 2 to 10 carbon atoms. preferable.

  Examples of the fatty acid component of the diamide compound include stearic acid (C18), eicosanoic acid (C20), behenic acid (C22), montanic acid (C28), triacontanoic acid (C30), and the like. Examples of the diamine component of the diamide compound include ethylenediamine, butylenediamine, hexanediamine, xylylenediamine, and bis (aminomethyl) cyclohexane. A diamide compound is obtained combining these, 1 type may be individual, or may use 2 or more types together. The fatty acid may have a side chain or a double bond, but a linear saturated fatty acid is preferred. From the above viewpoint, the diamide compound is particularly preferably a diamide compound obtained from a fatty acid mainly composed of stearic acid and a diamine mainly composed of ethylenediamine.

Examples of the fatty acid component of the diester compound include those listed above for the fatty acid component of the diamide compound. Examples of the diol component of the diester compound include ethylene glycol, propanediol, butanediol, hexanediol, xylylene glycol, and cyclohexanedimethanol. A diester compound is obtained combining these, and may be used individually by 1 type or may use 2 or more types together.
Among these, a diester compound obtained from a fatty acid mainly composed of montanic acid and a diol mainly composed of ethylene glycol and / or 1,3-butanediol is preferable.

  The addition amount of the diamide compound and / or diester compound is preferably 0.005 to 1.0 part by mass, more preferably 0.05 to 0.5 part by mass, and particularly preferably 0.12 with respect to 100 parts by mass of the polyamide. -0.5 mass part. If this added amount is 0.005 parts by mass or more, a whitening prevention effect can be expected by using it together with the crystallization nucleating agent, and if it is 1.0 parts by mass or less, the haze value of the container of the present invention is kept low. It becomes possible.

  As inorganic crystallization nucleating agents, glass fillers (glass fibers, crushed glass fibers (milled fibers), glass flakes, glass beads, etc.), calcium silicate fillers (wollastonite, etc.), mica , Talc, kaolin, potassium titanate whisker, boron nitride, layered silicate clay, nanofiller, carbon fiber, etc., which are usually used for thermoplastic resins, and these two or more may be used in combination. . The maximum diameter of the inorganic crystallization nucleating agent is preferably 0.01 to 5 μm. In particular, powder talc having a particle size of 3.0 μm or less is preferable, powder talc having a particle size of about 1.5 to 3.0 μm is more preferable, and powder talc having a particle size of 2.0 μm or less is particularly preferable. In addition, granular talc using rosin as a binder in this powdery talc is particularly preferable because it is well dispersed in polyamide. Organic crystallization nucleating agents include crystallization nucleating agents, capsules consisting of bilayer films of micro to nano level size, bis (benzylidene) sorbitol-based or phosphorus-based transparent crystal nucleating agents, rosinamide-based Gelling agents are preferred, and bis (benzylidene) sorbitol crystallization nucleating agents are particularly preferred.

  Bis (benzylidene) sorbitol is selected from bis (benzylidene) sorbitol and bis (alkylbenzylidene) sorbitol, and is a condensation product (diacetal) produced by acetalization reaction between sorbitol and benzaldehyde or alkyl-substituted benzaldehyde. Can be conveniently prepared by various techniques known in the art.

  Specific examples of bis (benzylidene) sorbitol include bis (p-methylbenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol, bis (N-propylbenzylidene) sorbitol, bis (p-isopropylbenzylidene) sorbitol, bis (p -Isobutylbenzylidene) sorbitol, bis (2,4-dimethylbenzylidene) sorbitol, bis (3,4-dimethylbenzylidene) sorbitol, bis (2,4,5-trimethylbenzylidene) sorbitol, bis (2,4,6-trimethyl) Benzylidene) sorbitol, bis (4-biphenylbenzylidene) sorbitol and the like.

  Examples of suitable alkyl-substituted benzaldehydes for preparing bis (benzylidene) sorbitol include p-methylbenzaldehyde, N-propylbenzaldehyde, p-isopropylbenzaldehyde, 2,4-dimethylbenzaldehyde, 3,4-dimethylbenzaldehyde, 2 2,4,5-trimethylbenzaldehyde, 2,4,6-trimethylbenzaldehyde, 4-biphenylbenzaldehyde.

  When adding a crystallization nucleating agent such as talc, mica, and clay to the polyamide, the crystallization speed of the polyamide is accelerated more than twice compared with the case of no addition, so it is good for injection molding applications that require a high molding cycle, In a deep drawn cup formed from a stretched film or sheet, if the crystallization speed is too fast, the film or sheet cannot be stretched due to crystallization, and the formability such as breakage or uneven elongation is extremely reduced. . However, since the crystallization nucleating agent of bis (benzylidene) sorbitol does not accelerate the crystallization speed even if it is added to polyamide, it is preferable when used in applications such as deep drawn cups formed from stretched films and sheets. .

  Furthermore, bis (benzylidene) sorbitol crystallization nucleating agent has been found not only to improve whitening but also to improve oxygen barrier properties when added to polyamide, and has the effect of improving both whitening and oxygen barrier properties. It is particularly preferable to use a crystallization nucleating agent of bis (benzylidene) sorbitol.

  The addition amount of the crystallization nucleating agent is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the polyamide. By adding these at least one crystallization nucleating agent to the polyamide in combination with a diamide compound and / or a diester compound, a synergistic effect of preventing whitening can be obtained.

  In the present invention, in order to impart further excellent oxygen barrier properties, the polyamide used in the present invention is mixed with one or more metal atoms selected from Group VIII transition metals of the Periodic Table of Elements, manganese, copper and zinc. Thus, an oxygen absorbing function can be imparted to the gas barrier layer.

In the present invention, a compound containing a metal atom (hereinafter referred to as a metal catalyst compound) is preferably used for adding and mixing the metal atom in the polyamide. The metal catalyst compound is used in the form of a low-valent inorganic acid salt, organic acid salt or complex salt of the metal atom.
Examples of inorganic acid salts include halides such as chlorides and bromides, sulfates, nitrates, phosphates, silicates, and the like. On the other hand, examples of the organic acid salt include a carboxylate, a sulfonate, and a phosphonate. Also, transition metal complexes with β-diketone or β-keto acid ester can be used. Of these, carboxylates, halides, and acetylacetonate complexes containing the above metal atoms are preferred because of their good oxygen absorption function.
One or more of the metal catalyst compounds can be added, but those containing cobalt as a metal atom are particularly excellent in oxygen absorption function and are preferably used.

  The concentration of the metal atom added to the polyamide is not particularly limited, but is preferably in the range of 0.01 to 0.10 parts by mass, more preferably 0.02 to 0.08 parts by mass with respect to 100 parts by mass of the polyamide. It is. If the addition amount of the metal atom is 0.01 parts by mass, the oxygen absorption function is sufficiently developed and the effect of improving the oxygen barrier of the multilayer container can be obtained. Moreover, even if it is 0.10 mass part or less, the improvement effect of oxygen barrier property is acquired according to barrier addition, and it is economical.

  The method of adding the metal catalyst compound to the polyamide is a method of melt-mixing the polyamide and the metal catalyst compound using an extruder or the like, mixing the metal catalyst compound with a solvent to form a solution or slurry, and then mixing with the polyamide. For example, a method of removing the solvent and attaching it to the polyamide, a method of adding a device capable of adding a metal catalyst compound to a device for producing a multilayer container, and the like.

  The polyamide used in the present invention has a matting agent, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a nucleating agent, a plasticizer, a flame retardant, an antistatic agent, an anti-coloring agent as long as the effects of the present invention are not impaired. Additives such as an anti-gelling agent can be added, but the present invention is not limited to those shown above, and various materials may be mixed.

  In addition, the polyamide used in the present invention has a polyethylene terephthalate product recovery, a modified polyethylene terephthalate product recovery containing a small amount of isophthalic acid component units, a polyamide product recovery, and / or a material that does not substantially change its properties. You may add the end material at the time of manufacture of a molded article, and polyester and / or polyamide collection | recovery materials, such as a nonstandard thing.

  When blending the polyamide used in the present invention and components added as necessary, the blending method is not limited, and a known blending method can be used. For example, a desired resin composition can be obtained by adding other components such as additives to the polyamide in the present invention and mixing in an extruder. Further, a master batch based on polyamide or polyester to which an additive of up to about 30% by mass is added may be prepared and mixed with polyamide or polyester.

Since the polyamide in the present invention is excellent in sealability as a sealant and flavor retention of contents, it can be used in the innermost layer of a container formed by fusing at least a part of the innermost layer. That is, this invention can provide the container which has the layer which consists of a molding material containing the said polyamide in an innermost layer, and melt | dissolves at least one innermost layer. As shown in FIGS. 1 to 3, for example, the container of the present invention uses the polyamide as a sealant for the innermost layer 2 of the container to form a seal portion 5 in which at least some innermost layers are fused. Here, the innermost layer of the container is a layer that comes into contact with the contents when the contents are filled in the container.
Examples of the container of the present invention include, but are not limited to, a direct blow bottle, a pouch, a combination of a cup and a lid of the cup, and an unstretched film packaging. For example, the direct blow bottle 1 shown in FIG. 1 has the seal part 5 in the pinch-off part. The pouch 7 shown in FIG. 2 has a seal portion 5 on the outer peripheral edge of the film. The cup-shaped container 8 with a lid shown in FIG. 3 has a seal portion 5 at the interface between the cup-shaped container body 9 and the lid material 6. In any form, a part of the innermost layer 2 using the polyamide in the present invention is fused to form the seal portion 5.
The proportion of polyamide in the molding material containing polyamide is usually 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more (100% by mass). % Is included).

Moreover, this invention can provide the multilayer molded object which has a layer which consists of a molding material containing the said polyamide. The multilayer molded body of the present invention can be used for a container in which the layer made of the molding material constitutes the innermost layer of the container, and at least some of the innermost layers are fused together. That is, the multilayer molded body of the present invention can be used for the container of the present invention.
Furthermore, the present invention is a method of using a multilayer molded body having a layer made of a molding material containing polyamide, in a container in which at least some innermost layers are fused together, and made of the molding material. It is possible to provide a method for using a multilayer molded body in which the layer is used as an innermost layer of a container.
The multilayer molded body of the present invention has a shape included in the container of the present invention described above, and further has a film shape, a sheet shape, and a cup shape, a bottle shape or a pouch shape having an opening. However, it is not limited to these.
The multilayer molded body of the present invention is useful for the container of the present invention described above, a bottle body, a packaging material such as a cup-shaped container body 9 and a cup-shaped container lid 6 as shown in FIG.

Examples of the method for producing the container of the present invention include a method of fusing the innermost layers of the container at a temperature not higher than the melting point of the polyamide. If this fusing temperature is lower than the melting point of the polyamide, the sealing temperature is usually close to that of polyolefin used as a sealant, and the productivity in the heat sealing process is not extremely reduced, and the energy to be sealed Cost is not much different.
When the container of the present invention is a direct blow bottle, there is no particular problem under normal molding conditions. However, if the temperature on the polyamide flow path in the cylindrical die is preferably about -10 ° C, the melting point of the polyamide, By sufficiently cooling the mold temperature within the mold at 80 ° C. or lower, the inner surfaces of the containers can be fused together, and a pinch-off portion is formed, which is preferable.
In the case of heat sealing between the pouch or the lid of the cup and the cup, the sealing temperature is preferably in the range of 160 ° C. to 220 ° C. If the temperature is lower than this, the sealing performance as a sealant is insufficient, When the temperature is high, the appearance of the seal is extremely deteriorated.
The heat sealing method in the case of heat sealing between the pouch or the lid material of the cup and the cup is roughly classified into two types: a method using external heating and a method using internal heating. As a method by external heating, there are a method using friction heat such as an impulse seal and a spin weld method, a method using a flame, a method using a laser, an infrared ray, and a hot jet in addition to a heat seal method using a normal hot plate. on the other hand. The method by internal heating includes high frequency sealing and ultrasonic sealing, and any method may be used for heat sealing.

The container using the polyamide in the present invention as a sealant for the container as the innermost layer has a seal strength at least 35 N / 15 mm or more, more preferably 40 to 60 N / 15 mm, at a seal portion where at least some of the innermost layers are fused together. Can be secured. Therefore, even when the container is dropped or an internal pressure is applied to the container, the seal portion does not peel off. Further, the seal part is not peeled off during transportation immediately after sealing, and there is no particular problem even if the content of 85 ° C. or less is filled.
Furthermore, the sealing strength in the sealing part after the retorting treatment at 121 ° C. for 30 minutes is preferably 30 N / 15 mm or more, more preferably 35 to 60/15 mm. In this case, since it is 23 N / 15 mm or more, the sealant satisfies the JIS standard.

  The polyamide in the present invention preferably has a half crystallization time at a temperature drop of 160 ° C. of from 50 seconds to 200 seconds, particularly preferably from 50 seconds to 120 seconds. If the semi-crystallization time is shorter than this range, the sealing temperature becomes high and the sealing temperature and the sealing time increase, so that the appearance of the sealing surface is deteriorated and the sealing strength is insufficient. Further, if the semicrystallization time is longer than this range, the sealing temperature can be lowered, but there is a problem that the impact resistance is extremely lowered and the sealed portion of the container is ruptured when dropped.

The polyamide in the present invention has a crystallinity of 10% or less obtained from the following formula using an exothermic peak (heat amount A) due to crystallization of differential scanning calorimetry and an endothermic peak (heat amount B) due to melting. Is preferred.
Crystallinity = ((heat amount B) − (heat amount A)) / heat amount C × 100 (%)
Here, the amount of heat C is the heat of crystal fusion, and its value is 151 J / g. The amount of heat is indicated by an absolute value.
If the crystallinity is 10% or less, the crystallization speed does not become extremely slow, so that the hot tack property is excellent. From the above viewpoint, the crystallinity is more preferably 3 to 10%.
Here, the crystallinity can be adjusted to 10% or less by copolymerizing the copolymer component, preferably other monomers such as aromatic dicarboxylic acid.

  In addition, for containers that require easy peel properties such as a sealing part between a lid and a cup and a partition part such as a two-chamber pouch, the polyamide in the present invention can also be used as an easy peel material, and the necessary sealing strength and container According to the sterilization conditions, it can be used by blending with other resins. As other resins, polyamides such as nylon-6IT, nylon 6 and nylon 66, polyesters such as PET and PBT, polyolefins such as polypropylene and polyethylene, polystyrene, and the like can be used, but various kinds of resins are not limited thereto. Materials may be mixed. Furthermore, it is preferable to use a structure that positively causes interfacial delamination or delamination by combining a multilayer structure of a support layer such as PET and a layer made of a molding material containing polyamide in the present invention. Further, a combination with an easy-opening mechanism can be provided, and examples include, but are not limited to, an easy-opening mechanism such as an epoch seal of Toyo Seikan Co., Ltd. In the case of providing an easy opening mechanism, the seal strength at the time of opening is preferably 20 N / 15 mm or less, and in order to open more easily, 15 N / 15 mm or less is preferable.

  When impact resistance such as drop resistance is required for a container using the polyamide in the present invention for the innermost layer, an elastomer can be blended with the polyamide within a range not impairing the effects of the present invention. The elastomer is preferably an ethylene-propylene random copolymer, nylon 12 elastomer or the like, but is not limited thereto, and various materials may be mixed.

The thickness of the innermost layer using the polyamide in the present invention as a sealant is preferably about 5 to 100 μm. If the thickness is 5 μm or more, necessary sealing properties can be obtained. In addition, if the thickness is 100 μm or less, there is no problem that the sealing temperature is increased or the sealing time becomes long, and if the thickness is too thick, it may cause fluff at the time of opening and impair the appearance, It is possible to easily solve the problems that the strength becomes too strong, a preferable opening property cannot be obtained, the flexibility is impaired, and the impact resistance at the time of dropping is inferior.
Since the container using the polyamide in the present invention for the innermost layer can suppress oxygen permeation from the seal wall surface, the oxygen barrier property is excellent when the innermost layer is thick.

  Examples of the multilayer structure of the multilayer molded article of the present invention useful for direct blow bottles and cup-shaped containers include PP / adhesive / polyamide in the present invention, PP / regrind / polyamide in the present invention, PP / Examples include adhesives / polyamide blends in the present invention and PP / adhesives / EVOH / adhesives / polyamides in the present invention. The layer configuration shown above is an example, and the present invention is not limited to the above, and various layer configurations are possible if the polyamide of the present invention is used as the sealant in the innermost layer.

  The film packaging, pouch, and cup lid are formed of a single-layer or multilayer plastic film, but are preferably formed of a multilayer plastic film formed of the multilayer molded article of the present invention. There is no restriction | limiting in particular as a plastic film to be used, Although what is normally used for a pouch can be used, The polyamide in this invention is used as an innermost layer at least. Examples of plastic materials suitable for constituting the plastic film include crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly-4-methylpentene-1, low-, medium-, Or polyolefins such as high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), EVA saponified product, ethylene-ethyl acrylate copolymer (EEA), ion-crosslinked olefin copolymer (ionomer); polystyrene, styrene- Aromatic vinyl copolymers such as butadiene copolymers; halogenated vinyl polymers such as polyvinyl chloride and vinylidene chloride resins; polyacrylic resins; acrylonitrile-styrene copolymers, acrylonitrile-styrene-butadiene copolymers, etc. Nitrile polymer; nylon 6, nylon 66 Polyamides such as para or meta-xylylene adipamide, polyethylene terephthalate, polyesters polytetramethylene terephthalate; various polycarbonates; fluorine-based resin; a thermoplastic resin such as polyacetal such as polyoxymethylene, and the like.

  Examples of the multilayer structure of the multilayer molded article of the present invention useful for pouches and coextruded films include biaxially stretched polyamide film / polyamide film of the present invention, biaxially stretched PET film / polyamide film of the present invention, biaxial stretch PET film / biaxially stretched polyamide film / polyamide film in the present invention, biaxially stretched PET film / adhesive / biaxially stretched polyamide film / adhesive / aluminum / polyamide film in the present invention, biaxially stretched vapor deposited PET film / adhesive / Polyamide film in the present invention, biaxially stretched polyamide film / adhesive / PVDC film / adhesive / polyamide film in the present invention, PP film / adhesive / biaxially stretched polyamide film / adhesive / polyamide film in the present invention, 2 Axial stretch polypro Ren film / adhesive / polyamide film in the present invention, PET film / EVOH film / polyamide film in the present invention, PP film / polyamide film in the present invention, nylon 6 film / EVOH film / nylon 6 film / polyamide film in the present invention, etc. Is mentioned. The layer configuration shown above is an example, and the present invention is not limited to the above, and various layer configurations are possible if the polyamide of the present invention is used as the sealant in the innermost layer.

  The plastic film can be produced by an ordinary method such as a casting method, a T-die method, a calendar method, or an inflation method. The laminated film can be produced by a conventional method such as dry lamination of a film formed in advance, coating on a base film, or melt co-pressing. Moreover, in order to raise the interlayer intensity | strength of each resin layer, an adhesive agent and adhesive resin can be used. As the adhesive, an epoxy resin, a urethane resin, a polyethyleneimine resin, or the like can be used. Adhesive resins include EVA, ethylene-maleic anhydride copolymers, EAA, EEA, ethylene-methacrylate-glycidyl acrylate terpolymers, or various basic polyolefins such as acrylic acid and methacrylic acid. Saturated fatty acids, maleic acids, fumaric acids, dibasic unsaturated fatty acids such as itaconic acid or grafted with these anhydrides, such as maleic acid grafted EVA, maleic acid grafted ethylene-α-olefin copolymers, etc. Well-known ones can be used as appropriate. Moreover, LLDPE or LDPE can be used instead of PP for applications such as boil and hot pack instead of retort processing. The layer configuration shown above is an example, and the present invention is not limited to the above, and various layer configurations are possible if the polyamide of the present invention is used as the sealant in the innermost layer.

The container and multilayer molded body of the present invention are excellent in sealability as a sealant by using a layer made of a molding material containing polyamide having a specific composition as the innermost layer, and sealability and impact resistance after heat sterilization In addition, the chemical resistance of the contents and the flavor retention of the contents are excellent.
In the container of the present invention, for example, carbonated drinks, juice, water, milk, sake, whiskey, shochu, coffee, tea, jelly drinks, liquid drinks such as health drinks, seasoning liquid, sauce, soy sauce, dressing, liquid soup, Condiments such as mayonnaise, miso, grated spices, pasty foods such as jam, cream and chocolate paste, liquid foods such as liquid soup, boiled foods, pickles and stew, and soba, udon and ramen Raw and boiled noodles, boiled noodles, polished rice, moisture-conditioned rice, non-washed rice, etc. cooked rice, cooked cooked rice, processed rice products such as gomoku rice, red rice, rice bran, powder soup, dashi soup, etc. High-moisture foods such as jelly powder, jelly and pudding, low-moisture foods such as dried vegetables, coffee beans, coffee powder, tea, and confectionery made from grains, and other pesticides and insecticides Can store various articles such as solid and solution chemicals such as liquids and pastes, lotions, cosmetic creams, cosmetic milks, hair styling agents, hair dyes, shampoos, soaps, detergents, etc. .

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, the measurement for evaluation in this invention was based on the following method.

(1) Relative viscosity of polyamide 1 g of polyamide was precisely weighed and dissolved in 100 ml of 96 mass% sulfuric acid at 20-30 ° C with stirring. After completely dissolving, 5 ml of the solution was quickly taken into a Cannon-Fenceke viscometer, and left for 10 minutes in a constant temperature bath at 25 ° C., and then the dropping speed (t) was measured. Moreover, the dropping speed (t0) of 96 mass% sulfuric acid itself was measured similarly. The relative viscosity was calculated from t and t0 according to the following formula.
Relative viscosity = t / t0

(2) Half crystallization time of polyamide Using a semi-crystallization time measuring device MK701 (Kotaki Seisakusho), 5 layers of 100 μm thick polyamide films were melted in a hot air environment at 260 ° C. for 3 minutes by the depolarization intensity method. Then, the half crystallization time when crystallization was performed in an oil bath at 160 ° C. was determined.

(3) Crystallinity and melting point of polyamide Using DSC-60 manufactured by Shimadzu Corporation, DSC measurement (differential scanning calorimetry) was performed under a nitrogen stream at a heating rate of 10 ° C./min. The crystallinity was determined from the exothermic peak (calorie A) due to crystallization and the endothermic peak (calorie B) due to melting using the following equation. The heat of crystal fusion (heat quantity C) was 151 J / g.
Crystallinity = ((heat amount B) − (heat amount A)) / heat amount C × 100 (%)
The absolute value was used for the amount of heat.
The melting point was determined from the temperature at the top of the endothermic peak due to melting.

(4) Sensory test In the case of blow bottles and cups, boiled distilled water is placed in a container using the polyamide of the present invention as the innermost layer. In the case of a pouch, the end portion was heat sealed with a hot plate sealing machine. The interface temperature during heat sealing was 180 ° C. in all cases. Thereafter, it was kept for 30 minutes, cooled to room temperature, left at room temperature for 1 month, and tested for flavor and odor after opening. Regarding the filling amount, the blow bottle is 150 ml, the pouch is 70 ml, and the cup is 30 ml. Use distilled water as a blank for comparison. The sensory test was carried out by 10 panelists according to the following criteria, and the average values were compared.
(Evaluation criteria)
0: Does not feel strange taste or smell 1: Feels a slight difference from the blank 2: Feels a difference from the blank 3: Feels a considerable difference from the blank

(5) T peel test of seal part A container using the polyamide of the present invention as the innermost layer was conditioned for 1 week in an environment of 23 ° C. and 50% RH. For blow bottles, the pinch-off part is cut out to a width of 15 mm, the sealing part of the cup and the lid, and the sealing part of the pouch are similarly cut out to a width of 15 mm. Using a Toyo Seiki strograph, the speed is 300 mm / min. A peel test was performed. The maximum point load at the time of peeling was measured, and this was used as a T peel load, and the seal strength was evaluated. The number of measurements was 5 each.

(6) T-peel test of seal part after retort treatment The container was filled with water and then heat-sealed by the same method as in (4) above. Thereafter, a retort treatment machine (SR-240 manufactured by Tommy Seiko Co., Ltd.) was subjected to retort treatment at 121 ° C. for 30 minutes, and after conditioning for 1 week, a T peel test was conducted by the same method as in (5) above. The seal strength after the treatment was evaluated. The seal strength is the pinch-off part for blow bottles, the heat seal part for cups and lids for cups and lids, and the seal strength for seals between films for pouches. is there.

(7) Peeling confirmation after drop test After filling water in a container using the polyamide used in the present invention for the innermost layer, heat sealing was performed by the same method as in (4) above. Then, after storing in a refrigerator at 5 ° C. for 24 hours, it was dropped horizontally on a concrete surface from a height of 120 cm above the ground at a room temperature of 5 ° C. While repeating this 10 times, the presence or absence of peeling of the seal portion was confirmed. In addition, as shown in FIGS. 1-3, the seal part 5 is a pinch-off part in the case of a blow bottle, in the case of a cup and a lid material, in the case of a heat seal part of a cup and a lid material, in the case of a pouch, It is a seal part between film inner surfaces.
Regarding the filling amount, the blow bottle is 150 ml, the pouch is 70 ml, and the cup is 30 ml. In this drop test, the number of containers tested was 5 bags each.

(8) Confirmation of peeling after hot pack Immediately after filling hot water at 85 ° C. into a container using the polyamide of the present invention as the innermost layer, heat sealing was performed by the same method as in the above (4). Thereafter, the presence or absence of peeling of the seal portion after 10 seconds was visually observed to confirm the presence or absence of peeling of the seal portion. In addition, as shown in FIGS. 1-3, the seal part 5 is a pinch-off part in the case of a blow bottle, in the case of a cup and a lid material, in the case of a heat seal part of a cup and a lid material, in the case of a pouch, It is a seal part between film inner surfaces. Regarding the filling amount, the blow bottle is 150 ml, the pouch is 70 ml, and the cup is 30 ml. In this hot pack test, the number of test containers was 5 bags each.

Example 1
(Polymer melt polymerization)
14387.6 g (98.444 mol) of adipic acid precisely weighed in a reaction vessel having an internal volume of 50 liters equipped with a stirrer, a partial condenser, a full condenser, a thermometer, a dropping funnel and a nitrogen introduction tube, and a strand die, high purity Add 1043.97 g (6.228366 mol) of isophthalic acid, 13.6072 g (0.1284 mol) of sodium hypophosphite, 9.478 g (0.1155 mol) of sodium acetate, and after substituting with nitrogen sufficiently, a smaller amount of nitrogen stream Under stirring, the system was heated to 170 ° C. with stirring. To this, 14178.3 g (104.099 mol) of metaxylylenediamine was added dropwise with stirring, and the inside of the system was continuously heated while removing the condensed water produced. After completion of the dropwise addition of metaxylylenediamine, the internal temperature was 260 ° C. and the reaction was continued for 40 minutes. Thereafter, the inside of the system was pressurized with nitrogen, and the polymer was taken out from the strand die and pelletized to obtain about 24 kg of polyamide.

(Polyamide solid phase polymerization)
Next, the polyamide is charged into a tumble dryer with a jacket provided with a nitrogen gas introduction tube, a vacuum line, a vacuum pump, and a thermocouple for measuring the internal temperature, and the purity inside the tumble dryer is 99% by volume while rotating at a constant speed. After sufficiently replacing with the above nitrogen gas, the tumble dryer was heated under the same nitrogen gas stream, and the pellet temperature was raised to 150 ° C. over about 150 minutes. When the pellet temperature reached 150 ° C., the pressure in the system was reduced to 0.13 kPa (1 torr) or less. The temperature was further raised, and the pellet temperature was raised to 200 ° C. over about 70 minutes, and then held at 200 ° C. for 30 minutes. Next, N-MXD6 (polyamide 1 relative viscosity 2.65) obtained by introducing nitrogen gas having a purity of 99% by volume or more into the system and cooling while rotating the tumble dryer and copolymerizing 3 mmol% of isophthalic acid. ) Using this polyamide 1, a film having a thickness of 100 μm was prepared with a twin-screw extruder, and the half crystallization time was measured. The obtained polyamide 1 was vacuum-dried at 140 ° C. for 6 hours, and then the relative viscosity, crystallinity, and melting point were determined. The results are shown in Table 1.

(Production and evaluation of direct blow bottle)
PP (Nippon Polypro Corp.) from the outer layer in a direct blow bottle prototype machine consisting of three 40mm diameter single screw extruders capable of extruding up to 3 types and 5 layers of parison, cylindrical die and 200cc container mold. Novatec PP EC9), adhesive (Modic P604V, manufactured by Mitsubishi Chemical Corporation), polyamide 1 as the innermost barrier layer (sealant layer), average total thickness of about 0.8 mm in four circumferential directions, barrier layer A direct blow bottle 1 shown in FIG. 1 having a thickness of about 0.3 mm and having a thickness of 200 cc was prepared. In addition, the molding temperature of the three extruders was 200 ° C. to 240 ° C., the temperature of the cylindrical die was 230 ° C., and the mold temperature was 20 ° C., and good bottles could be prototyped. The bottle was subjected to a sensory test, a T peel strength, a drop test, a hot pack test, and a T peel test after retorting. In addition, as a cover material film used for a sensory test, a drop test, a hot pack test, and a T peel test after retort, a multilayer film used for a pouch described later is used. Sealing was performed. The heat sealing temperature on the film surface at this time was 180 ° C., the sealing time was 5 seconds, and the sealing pressure was 0.2 MPa. The results are shown in Table 1.

(Preparation and evaluation of flat pouch)
As a packaging material constituting the pouch, a biaxially stretched polyethylene terephthalate film (thickness 12 μm), a biaxially stretched nylon film (thickness 15 μm) from the outer layer, and a polyamide 1 as an innermost sealant layer made into a film by an extruder A multilayer film laminated with a urethane adhesive using a thickness of 80 μm was used. From this multilayer film, a flat pouch 7 having a length of 150 mm and a width of 200 mm shown in FIG. 2 was prepared. At this time, the heat sealing temperature on the film surface was 180 ° C., the sealing time was 3 seconds, and the sealing pressure was 0.2 MPa. A sensory test, a T peel strength, a drop test, a hot pack test, and a T peel test after retorting were performed on this pouch. The results are shown in Table 1.

(Creation and evaluation of cup)
Using a multilayer sheet manufacturing apparatus equipped with three extruders, feed block, T die, cooling roll, winder, etc., PP (from Nippon Polypro, Novatec PP, grade name: FY6) from the first extruder At 240 ° C., the adhesive resin (Mitsui Chemicals, trade name: Admer, Grade: QB550) was extruded from the second extruder at 230 ° C., and the polyamide 1 was extruded from the third extruder at 250 ° C. A multilayer sheet having a three-kind three-layer structure of PP layer / adhesive resin layer / polyamide 1 layer was produced through a feed block. The thickness of each layer was 425/25/80 (μm). Next, using a vacuum / pressure forming machine equipped with plug assist, thermoforming is performed so that the polyamide 1 layer becomes the innermost layer when the sheet surface temperature reaches 170 ° C., and the diameter is 62 mm × bottom diameter 52 mm × depth. A cup-shaped container body having a thickness of 28 mm, a surface area of 73 cm ² and a volume of 70 ml was obtained. Moreover, the multilayer film used for the pouch was used as the lid material film, and after filling with water according to the test conditions, heat sealing was performed, and the lid-shaped cup-shaped container 8 shown in FIG. 3 was created. The heat sealing temperature on the film surface at this time was 180 ° C., the sealing time was 5 seconds, and the sealing pressure was 0.2 MPa. The sensory test, T peel strength, drop test, hot pack test, and T peel test after retorting of the cup-shaped container with lid were performed. The results are shown in Table 1.

Example 2
Polymerization was carried out in the same manner as in Example 1 except that 3.5 mol% of high-purity terephthalic acid was copolymerized instead of isophthalic acid as a copolymerization component to obtain polyamide 2 having a relative viscosity of 2.65. Except that this polyamide 2 was used, a container was made in the same manner as in Example 1 and subjected to various evaluations. The results are shown in Table 1.

Example 3
Polymerization was conducted in the same manner as in Example 1 except that 1,3-bis (aminomethyl) cyclohexane was used instead of isophthalic acid as a copolymerization component, and the relative viscosity was 2. 65 polyamides 3 were obtained. Except that this polyamide 3 was used, a container was made in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 1.

Comparative Example 1
Polymerization was carried out in the same manner as in Example 1 except that N-MXD6 that was not copolymerized with isophthalic acid was polymerized to obtain polyamide 4 having a relative viscosity of 2.65. Except that this polyamide 4 was used, a container was made in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 2. However, with regard to the direct blow bottle, molding was performed at the melting point of polyamide 4 + 20 ° C. on the polyamide 4 extruder and the flow path of the cylindrical die. Moreover, the temperature at the time of heat-sealing was not 240 degreeC, and it did not weld.

Comparative Example 2
Polymerization was carried out in the same manner as in Example 1 except that 7.5 mol% of isophthalic acid was copolymerized to obtain polyamide 5 having a relative viscosity of 2.65. A container was prototyped and various evaluations were performed in the same manner as in Example 1 except that this polyamide 5 was used. The results are shown in Table 2.

Comparative Example 3
The container was made in the same manner as in Example 1 except that the inner surface of the container was not a polyamide used in the present invention and was a PP single layer container, and various evaluations were performed. The results are shown in Table 2.

The container of Comparative Example 1 using N-MXD6 on the inner surface was greatly inferior in sealing performance as a sealant, sealing performance after retorting, and in impact resistance. This is probably because the melting point of the polyamide is higher than in Examples 1 to 3, and the sealing temperature is high, so that bubbles generated in the seal portion and the appearance of the seal are poor. Further, the container of Comparative Example 2 using a polyamide containing a large amount of isophthalic acid units on its inner surface was greatly inferior in impact resistance, and also had poor sealing properties as a sealant and after heat sterilization. This is presumably because the semi-crystallization time of the polyamide is too long as compared with Examples 1 to 3, and this is due to poor sealing due to a decrease in the temperature of the seal portion before complete welding.
On the other hand, it can be seen that the containers using the polyamides of Examples 1 to 3 as the innermost layer have excellent sealing properties as a sealant, and therefore have excellent sealing properties and impact resistance after heat sterilization.

  Since the polyamide according to the present invention is excellent in sealing properties as a sealant, it is excellent in sealing properties after heat sterilization, impact resistance, and the chemical resistance of the content and the flavor retention and oxygen barrier properties of the content. The container of the present invention using a layer made of a molding material containing polyamide as the innermost layer can be stored for a long period of time, and the effect is great.

1; direct blow bottle 2; innermost layer (polyamide layer)
3; intermediate layer 4; outermost layer 5; seal part 6; lid material 7; pouch 8; cup-shaped container with lid 9;

Claims (10)

A polyamide obtained by polycondensation of metaxylylenediamine and adipic acid with at least one copolymer component selected from 1,3-bis (aminomethyl) cyclohexane, isophthalic acid and terephthalic acid , The content of the structural unit derived from the copolymer component is in the range of 3 to 3.5 mol%, and the crystallinity calculated from the differential scanning calorimetry of the polyamide is 5.2 % or more and 9.1 %. The container which has the layer which consists of the molding material containing the following polyamide in an innermost layer, Comprising: At least one part innermost layer fuse | melts. Copolymerization component A container according to claim 1 which is isophthalic acid. The container according to claim 1 or 2 , wherein a seal strength at a seal portion where the innermost layers are fused is 35 N / 15 mm or more. The container according to any one of claims 1 to 3 , wherein a seal strength at a seal portion where the innermost layers after retorting at 121 ° C for 30 minutes are fused is 30 N / 15 mm or more. The container according to any one of claims 1 to 4 , wherein the temperature-lowering semi-crystallization time of polyamide at 160 ° C is from 50 seconds to 200 seconds. It is a method of manufacturing the container in any one of Claims 1-5 , Comprising: The manufacturing method of the container which fuses the said innermost layers at the temperature below the melting | fusing point of polyamide. A layer made of a molding material containing polyamide constitutes the innermost layer of the container, and is a multilayer molded body used for a container formed by fusing at least some of the innermost layers, wherein the polyamide is metaxylylenediamine and Obtained by polycondensation of adipic acid with one or more copolymer components selected from 1,3-bis (aminomethyl) cyclohexane, isophthalic acid and terephthalic acid , and derived from the copolymer component in the polyamide A multilayer molded body having a constituent unit content of 3 to 3.5 mol% and a crystallinity calculated from differential scanning calorimetry of polyamide of 5.2 % to 9.1 %. The multilayer molded article according to claim 7 , wherein the copolymer component is isophthalic acid. The multilayer molded article according to claim 7 or 8 , wherein the temperature-lowering semi-crystallization time of polyamide at 160 ° C is from 50 seconds to 200 seconds. A polyamide obtained by polycondensation of metaxylylenediamine and adipic acid with at least one copolymer component selected from 1,3-bis (aminomethyl) cyclohexane, isophthalic acid and terephthalic acid , The content of the structural unit derived from the copolymer component is in the range of 3 to 3.5 mol%, and the crystallinity calculated from the differential scanning calorimetry of the polyamide is 5.2 % or more and 9.1 %. The multilayer molded body having a layer made of a molding material containing polyamide, which is the following, is used in a container formed by fusing at least some of the innermost layers with the layer made of the molding material as the innermost layer of the container, How to use multilayer molded body.

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