JP2012111506A - Multi-layer bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer bottle excellent in transparency and barrier properties which has a large degree of freedom in design since separation due to a fall and an impact cannot take place easily and it is not necessary to make small an unevenness section or a bending section for preventing the exfoliation.SOLUTION: The multi-layer bottle includes: the outermost layer; the innermost layer; and at least one layer of a barrier layer located between the outermost layer and the innermost layer. These outermost layer and the innermost layer are mainly formed of a thermoplastic polyester resin [polyester (A)] obtained by polymerizing: a dicarboxylic acid component comprising 80 mol% or more of a terephthalic acid; and a diol component comprising 80 mol% or more of ethylene glycol. The barrier layer is formed of a blend composed of at least two components of: a polyamide (B) obtained by polycondensation of a diamine component comprising 70 mol% or more of meta-xylylenediamine and a dicarboxylic acid component comprising 70 mol% or more of a C4-C20 α, ω-straight chain aliphatic dicarboxylic acid; and a polyester (C) comprising a copolymerization component having a sulfonic acid metal salt.

Description

  The present invention relates to prevention of delamination of multilayer bottles having excellent gas barrier properties. Specifically, the multilayer bottle is filled with contents by improving interlayer adhesion between the innermost layer and the outermost layer and the intermediate layer. The multilayer bottle is prevented from delamination when the multilayer bottle is transported or subjected to an impact when dropped, and it is possible to avoid delamination without having a shape with few uneven parts and bent parts. The present invention relates to a multilayer bottle having high transparency and excellent barrier properties.

  Currently, plastic containers (such as bottles) mainly composed of polyester such as polyethylene terephthalate (PET) are widely used for tea, fruit juice drinks, carbonated drinks and the like. The proportion of small plastic bottles in plastic containers is increasing year by year. Since the ratio of the surface area per unit volume increases as the bottle becomes smaller, the shelf life of the contents tends to be shorter when the bottle is made smaller. In recent years, beer plastic bottles, which are easily affected by oxygen and light, and hot sale of plastic bottled tea have been sold, and the range of use of plastic containers has expanded, further improving the gas barrier properties of plastic containers. Is required.

  In response to the above requirements, carbon bottles, vapor deposition, and barrier resin coating are applied to multilayer bottles, blend bottles, and thermoplastic polyester resin single-layer bottles using thermoplastic polyester resin and gas barrier resin as a method of imparting gas barrier properties to the bottle. Barrier coating bottles have been developed.

  As an example of a multilayer bottle, a mold cavity is formed by injecting a thermoplastic polyester resin such as PET, which forms the innermost layer and the outermost layer, and a thermoplastic gas barrier resin such as polymetaxylylene adipamide (polyamide MXD6). A bottle in which a preform (parison) having a three-layer or five-layer structure obtained by filling is biaxially stretch blow molded has been put into practical use.

  Furthermore, a resin having an oxygen scavenging function for capturing oxygen in the container while blocking oxygen from outside the container has been developed and applied to a multilayer bottle. As the oxygen scavenging bottle, a multilayer bottle using polyamide MXD6 mixed with a transition metal catalyst as a gas barrier layer is preferable in terms of oxygen absorption rate, transparency, strength, moldability, and the like.

  The said multilayer bottle is utilized for containers, such as beer, tea, and a carbonated drink, from the favorable gas barrier property. Multi-layer bottles are used in these applications to maintain the quality of contents and improve shelf life, while delamination occurs between different resins, for example, the innermost layer and the outermost and intermediate layers. There is a problem that detracts from value.

  As a method for improving such a problem, a reverse flow control device capable of causing a fixed amount of reverse flow to the gas barrier layer side when the resin constituting the innermost layer and the outermost layer is finally injected into the mold cavity. Although it has been disclosed to improve the delamination resistance by using a rough mixed resin between layers and making a preform, there is a problem of using a special device (see Patent Document 1). ). In addition, when forming a multi-layer bottle by stretch blow, there is a method in which the primary molded product once blown is heated and shrunk and then blown again at a high pressure. However, this method may cause a defective shape of the molded product or may be complicated. There is a problem that it takes time and the delamination resistance decreases (see Patent Document 2).

  On the other hand, as an example of a blend bottle, a thermoplastic polyester resin such as PET and a thermoplastic gas barrier resin such as polymetaxylylene adipamide (polyamide MXD6) are dry blended and injection molded to fill the mold cavity. A bottle obtained by biaxially stretch-blowing a preform (parison) having a three-layer or five-layer structure obtained in this way has been put into practical use. Since the blend bottle is a single layer, delamination does not occur. However, since the blend has a high Haze and a unique pearl-like appearance, the transparency of the multilayer bottle is inferior.

As a method for improving the transparency of a blend bottle made of PET and polyamide MXD6, a blend bottle made of PET, MXD6, and sulfonic acid-modified PET has been disclosed. However, Haze is still high and improvement has been demanded (Patent Document 3). reference).

JP 2000-254963 A JP 2001-206336 A JP-A-2-135259

  The object of the present invention is to solve the above-mentioned problems, and in a multi-layer bottle, peeling due to dropping or impact is unlikely to occur, and it is not necessary to have a shape with few uneven parts and bent parts to prevent peeling, and the design flexibility is An object of the present invention is to provide a large multilayer bottle excellent in transparency and barrier properties.

  As a result of intensive research on the delamination resistance of multilayer bottles, the present inventors have made the barrier layer a specific composition, thereby improving energy relaxation against the impact of the barrier layer and improving the adhesion between the layers. The present inventors have found that a delamination can be prevented when dropped and a bottle having excellent transparency can be obtained.

That is, the present invention is as follows.
1. A multi-layer bottle comprising an outermost layer and an innermost layer, and at least one barrier layer located between the outermost layer and the innermost layer, wherein the outermost layer and the innermost layer comprise dicarboxylic acid containing 80 mol% or more of terephthalic acid A diamine component mainly composed of a thermoplastic polyester resin (polyester (A)) obtained by polymerizing a component and a diol component containing 80 mol% or more of ethylene glycol, and the barrier layer containing 70 mol% or more of metaxylylenediamine And a polyamide (B) obtained by polycondensation of a dicarboxylic acid component containing 70 mol% or more of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and a copolymer component having a sulfonic acid metal base A multilayer bottle comprising a blend of at least two components of polyester (C) containing
2. The multilayer bottle according to item 1, wherein the weight of the polyester (C) is 40 to 90% with respect to the weight of the barrier layer.
3. The multilayer bottle according to item 1, wherein the polyamide (B) has a number average molecular weight of 10,000 to 30,000.
4). The multilayer bottle according to item 1, wherein the copolymer component having a sulfonic acid metal base is 5-sodium sulfoisophthalic acid.
5. 5. The multilayer bottle according to item 1, wherein the polyester (C) contains 0.1 to 1 mol% of 5-sodium sulfoisophthalic acid. 6. The multilayer bottle according to item 1, wherein the melt viscosity ratio of polyamide (B) and polyester (C) is 0.4 to 1. The barrier layer is obtained by molding a multilayer structure pellet in which polyamide (B) and polyester (C) have a multilayer structure, and polyamide (B) is a core layer and polyester (C) is a skin layer. The multilayer bottle according to item 1.
8). The multilayer bottle according to claim 1, wherein the barrier layer contains 0.005 to 1.0 part by weight of a diamide compound and / or a diester compound with respect to 100 parts by weight of the total amount of the barrier layer.
9. 2. The multilayer bottle according to item 1, having a three-layer structure of polyester (A) layer / barrier layer / polyester (A) layer.
10. The multilayer bottle according to item 1, having a five-layer structure of polyester (A) layer / barrier layer / polyester (A) layer / barrier layer / polyester (A) layer.
11. The multilayer bottle according to item 1, wherein the weight of the barrier layer is 1 to 20% by weight based on the total weight of the multilayer bottle.

  According to the present invention, since delamination hardly occurs, the degree of freedom of the container shape can be increased, and a transparent multilayer bottle excellent in gas barrier properties can be obtained. Therefore, the industrial significance of the present invention is great. .

The thermoplastic polyester resin that may form the outermost layer, the innermost layer, and in some cases the intermediate layer of the multilayer bottle of the present invention comprises a dicarboxylic acid component in which 80 mol% or more, preferably 90 mol% or more is terephthalic acid. 80% by mole or more, preferably 90% by mole or more, a polyester resin obtained by polymerizing a diol component that is ethylene glycol (hereinafter abbreviated as “polyester (A)”).

  As the polyester (A), polyethylene terephthalate is preferably used. It becomes possible to exhibit excellent properties in all of transparency, mechanical strength, injection moldability, and stretch blow moldability of polyethylene terephthalate.

  As other dicarboxylic acid components other than terephthalic acid, isophthalic acid, diphenyl ether-4,4-dicarboxylic acid, naphthalene-1,4 or 2,6-dicarboxylic acid, adipic acid, sebacic acid, decane-1,10-carboxyl Acid, hexahydroterephthalic acid can be used. As other diol components other than ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis ( 4-hydroxyethoxyphenyl) propane or the like can be used. Furthermore, as a raw material monomer for the polyester resin A, an oxyacid such as p-oxybenzoic acid may be used.

  The intrinsic viscosity of the polyester (A) is 0.55 to 1.30, preferably 0.65 to 1.20. When the intrinsic viscosity is 0.55 or more, the multilayer preform can be obtained in a transparent amorphous state, and the mechanical strength of the resulting multilayer bottle is also satisfied. When the intrinsic viscosity is 1.30 or less, bottle molding is easy without impairing fluidity during molding.

  The outermost layer or the innermost layer is mainly composed of the polyester (A), but may be used by blending the polyester (A) with other thermoplastic resins and various additives within a range not impairing the characteristics of the present invention. it can. At that time, 90% by weight or more of the outermost layer or the innermost layer is preferably the polyester (A). Examples of the thermoplastic resin include thermoplastic polyester resins such as polyethylene-2,6-naphthalenedicarboxylate, polyolefin resins, polycarbonate, polyacrylonitrile, polyvinyl chloride, polystyrene, and the like. Examples of the additive include an ultraviolet absorber, an oxygen absorber, a colorant, and an infrared absorber (reheat additive) for accelerating the heating of the preform and shortening the cycle time during molding.

The barrier layer of the multilayer bottle of the present invention comprises a diamine component containing 70 mol% or more of metaxylylenediamine and a dicarboxylic acid component containing 70 mol% or more of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The polyamide (B) obtained by polycondensation and a polyester (C) containing a copolymer component having a sulfonic acid metal base are preferably used. By blending the polyamide (B) and the polyester (C), the flexibility of the barrier layer and the adhesion between the layers are improved, and the delamination resistance is improved. Moreover, the transparency of the barrier layer is improved.

The polyamide (B) used in the present invention comprises a diamine component mainly composed of metaxylylenediamine and a dicarboxylic acid component mainly composed of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. It is a polyamide obtained by polycondensation. The polyamide has high barrier performance and exhibits excellent properties in co-injection moldability and co-stretch blow moldability with polyester (A) (mainly polyethylene terephthalate) and polyester (C).

  The diamine component in the polyamide (B) contains metaxylylenediamine at 70 mol% or more, preferably 75 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. If the amount of metaxylylenediamine in the diamine component is less than 70 mol%, the gas barrier property of the polyamide (B) is lowered, which is not preferable. Examples of diamine components that can be used in addition to metaxylylenediamine in the present invention include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, Aliphatic diamines such as dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (amino) Methyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) de Aliphatic diamines such as phosphorus and bis (aminomethyl) tricyclodecane, diamines having aromatic rings such as bis (4-aminophenyl) ether, paraphenylenediamine, paraxylylenediamine, and bis (aminomethyl) naphthalene However, the present invention is not limited to these examples.

  The dicarboxylic acid component in the polyamide (B) is an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in an amount of 70 mol% or more, preferably 75 mol% or more, more preferably 80 mol% or more, particularly preferably. It contains 90 mol% or more. When it is in the above range, the polyamide has excellent barrier properties and moldability. Examples of the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms used in the present invention include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, Aliphatic dicarboxylic acids such as dodecanedioic acid can be exemplified, but among these, adipic acid and sebacic acid are preferable.

In the present invention, as the dicarboxylic acid other than the α, ω-linear aliphatic dicarboxylic acid, aromatic dicarboxylic acids exemplified by terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, etc. It can also be added. Furthermore, a small amount of monoamine or monocarboxylic acid may be added as a molecular weight regulator during the polycondensation of the polyamide.

  The polyamide (B) can be produced by a melt polycondensation method. For example, it is manufactured by a method in which a nylon salt composed of metaxylylenediamine and adipic acid is heated in the presence of water in a pressurized state and polymerized in a molten state while removing added water and condensed water. Further, it is also produced by a method in which metaxylylenediamine is directly added to molten adipic acid and polycondensed under normal pressure. In this case, in order to keep the reaction system in a uniform liquid state, metaxylylenediamine is continuously added to adipic acid, and during this time, the reaction system is raised so that the reaction temperature does not fall below the melting point of the generated oligoamide and polyamide. The polycondensation proceeds while warming.

  Polyamide (B) may be subjected to polycondensation by solid-phase polymerization after being produced by a melt polymerization method. The method for producing the polyamide is not particularly limited, and it is produced by a conventionally known method and polymerization conditions.

The number average molecular weight of the polyamide (B) is preferably 8000 to 30000, more preferably 9000 to 20000, and further preferably 9500 to 18000. Within this range, molding into a multilayer bottle is good, and the resulting multilayer bottle has excellent delamination resistance. Surprisingly, the transparency of the barrier layer made of polyamide (B) and polyester (C) is improved.

The reaction molar ratio of the polyamide (B) is preferably 0.97 to 0.995, more preferably 0.974 to 0.991, and still more preferably 0.976 to 0.989. It was found that the transparency of the barrier layer composed of polyamide (B) and polyester (C) is surprisingly in this range.

Here, the reaction molar ratio (r) is obtained by the following equation.
r = (1-cN-b (CN)) / (1-cC + a (CN))
In the formula, a: M1 / 2
b: M2 / 2
c: 18.015 (molecular weight of water)
M1: Molecular weight of diamine (g / mol)
M2: Molecular weight of dicarboxylic acid (g / mol)
N: Terminal amino group concentration (equivalent / g)
C: Terminal carboxyl group concentration (equivalent / g)

Needless to say, when synthesizing polyamide from monomers having different molecular weights as diamine and dicarboxylic acid components, M1 and M2 are calculated according to the blending ratio (molar ratio) of the monomers blended as raw materials. If the inside of the synthesis kettle is a complete closed system, the molar ratio of the charged monomers and the reaction molar ratio are the same, but the actual synthesis apparatus cannot be a complete closed system. The ratio and the reaction molar ratio do not always coincide. Since the charged monomer does not always react completely, the charged molar ratio and the reaction molar ratio are not always the same. Therefore, the reaction molar ratio means the molar ratio of the actually reacted monomer obtained from the end group concentration of the finished polyamide.

  A phosphorous compound can be added to the polyamide (B) in order to enhance the processing stability during melt molding or to prevent the polyamide (B) from being colored. As the phosphorus compound, a phosphorus compound containing an alkali metal or an alkaline earth metal is preferably used. For example, an alkali metal or alkaline earth metal phosphate such as sodium, magnesium, calcium, hypophosphite, phosphorus Acid salts may be mentioned, but those using alkali metal or alkaline earth metal hypophosphites are particularly preferred because they are particularly excellent in the anti-coloring effect of polyamide. The density | concentration of a phosphorus compound is 1-500 ppm as a phosphorus atom, Preferably it is 350 ppm or less, More preferably, it is 200 ppm or less. Even if the phosphorus atom concentration exceeds 500 ppm, there is no change in the anti-coloring effect. Rather, the haze of the film obtained using this increases, which is not preferable.

The polyester (C) containing a copolymer component having a sulfonic acid metal base and a copolymer component having a sulfonic acid metal base specifically include 5-sodium sulfoisophthalic acid, dimethyl 5-sodium sulfoisophthalate, and bis. (2-Hydroxyethyl) 5-sodium sulfoisophthalate, bis (4-hydroxybutyl) 5-sodium sulfoisophthalate and the like can be exemplified, among which 5-sodium sulfoisophthalic acid is most preferable. When the polyester (C) contains such a component, the transparency when blended with the polyamide (B) is improved.

The amount of the copolymer component having a sulfonic acid metal base is preferably from 0.1 to 1 mol%, particularly preferably from 0.2 to 0.7 mol%, particularly preferably 0.3, based on the polyester (C). -0.45 mol%. Within this range, transparency when the polyester (C) and the polyamide (B) are blended becomes good. Moreover, the strength of the barrier layer is improved, and a multilayer bottle having excellent delamination resistance can be obtained.

The mixing ratio of the polyamide (B) and the polyester (C) is preferably 40 to 90% with respect to the barrier layer weight, more preferably 45 to 70%, and still more preferably 50 to 60%. Within this range, a multi-layer bottle having good transparency and barrier properties and excellent delamination resistance can be obtained.

The melt viscosity ratio of the polyamide (B) and the polyester (C), that is, the melt viscosity of the polyamide (B) / the melt viscosity of the polyester (C) is preferably 0.4 to 1, more preferably 0.5 to 0.9, 0.6 to 0.8 is more preferable. Within this range, the delamination resistance of the multilayer bottle becomes good. Here, the melt viscosity is an apparent melt viscosity measured using a 1 mmφ × 10 mm capillary at 270 ° C. and a shear rate of 122 / sec.

When producing a multilayer bottle having polyamide (B) and polyester (C) as a barrier layer, a method of dry blending polyamide (B) and polyester (C) and supplying them to a molding machine, a twin-screw extruder or A method of supplying pellets obtained by melt-kneading using an extruder such as a single screw extruder to a molding machine, or a multilayer structure pellet in which polyamide (B) is a core layer and polyester (C) is a skin layer in advance Examples of the method include molding and supplying a multilayer pellet to a molding machine. Among these, a method using a pellet having a multilayer structure is most preferable. By using pellets having a multilayer structure, the haze is further reduced, and a multilayer bottle with less pearly luster can be obtained.

There is no particular restriction on the blending method of polyamide (B) and polyester (C), and it may be supplied by dry blending when creating a bottle preform, such as a single screw extruder or a twin screw extruder prior to preform production. Melt blending may be used, or a master batch may be prepared by melt blending.

Further, the barrier layer has a resin (D) other than polyamide (B) or thermoplastic resin (C), for example, nylon 6, nylon 66, nylon 6,66, nylon 6I / 6T, as long as the purpose is not impaired. One or a plurality of resins such as polyester, olefin, and phenoxy resin can be blended. In addition, inorganic fillers such as glass fibers and carbon fibers; plate-like inorganic fillers such as glass flakes, talc, kaolin, mica, montmorillonite, and organized clay; impact modifiers such as various elastomers; crystal nucleating agents ; Lubricants such as fatty acid amides, fatty acid metal salts, fatty acid amides; copper compounds, organic or inorganic halogen compounds, hindered phenols, hindered amines, hydrazines, sulfur compounds, phosphorus compounds, etc. Agents: Thermal stabilizers, anti-coloring agents, UV absorbers such as benzotriazoles, release agents, plasticizers, coloring agents, flame retardants and other additives, compounds containing cobalt metal which is a compound that imparts oxygen scavenging ability Further, additives such as alkali compounds for the purpose of preventing gelation of polyamide can be added.

  In the multilayer bottle of the present invention, a portion having a low draw ratio (1 to 2.5 times) may occur depending on the shape of the preform and the bottle. When the barrier layer in the low draw ratio part absorbs water, it may whiten. By adding an anti-whitening agent to the barrier layer as necessary, whitening is suppressed and a multilayer bottle with good transparency can be obtained.

  The whitening inhibitor is a fatty acid metal salt having 18 to 50 carbon atoms, preferably 18 to 34 carbon atoms. With 18 or more carbon atoms, whitening prevention can be expected. Further, when the number of carbon atoms is 50 or less, uniform dispersion in the barrier layer is good. Fatty acids may have side chains and double bonds, but linear saturated such as stearic acid (C18), eicosanoic acid (C20), behenic acid (C22), montanic acid (C28), triacontanoic acid (C30) Fatty acids are preferred. The metal that forms a salt with the fatty acid is not particularly limited, but sodium, potassium, lithium, calcium, barium, magnesium, strontium, aluminum, zinc, etc. are exemplified, and sodium, potassium, lithium, calcium, aluminum, and zinc are particularly preferable.

  One type of fatty acid metal salt may be used, or two or more types may be used in combination. In the present invention, the particle diameter of the fatty acid metal salt is not particularly limited. However, the smaller the particle diameter, the easier it is to disperse uniformly in the barrier layer, so the particle diameter is preferably 0.2 mm or less.

  The addition amount of the fatty acid metal salt is preferably 0.005 to 1.0 part by weight, more preferably 0.05 to 0.5 part by weight, particularly preferably 0.12 with respect to 100 parts by weight of the total amount of the barrier layer. -0.5 parts by weight. Addition of 0.005 part by weight or more with respect to 100 parts by weight of the total amount can be expected to prevent whitening. Moreover, it becomes possible to keep the cloudiness of the multilayer bottle obtained that the addition amount is 1.0 part by weight or less with respect to the total amount of 100 parts by weight.

  Instead of the fatty acid metal salt, a compound selected from the following diamide compounds and diester compounds may be added as a whitening inhibitor. One or two or more diamide compounds may be added, one or two or more diester compounds may be added, one or two or more diamide compounds and one or two or more types These diester compounds may be used in combination.

  The diamide compound is obtained from a fatty acid having 8 to 30 carbon atoms and a diamine having 2 to 10 carbon atoms. When the fatty acid has 8 or more carbon atoms and the diamine has 2 or more carbon atoms, an effect of preventing whitening can be expected. Further, when the fatty acid has 30 or less carbon atoms and the diamine has 10 or less carbon atoms, uniform dispersion is good. The fatty acid may have a side chain or a double bond, but a linear saturated fatty acid is preferred.

  Examples of the fatty acid component of the diamide compound include stearic acid (C18), eicosanoic acid (C20), behenic acid (C22), montanic acid (C28), and triacontanoic acid (C30). Examples of the diamine component of the diamide compound include ethylenediamine, butylenediamine, hexanediamine, xylylenediamine, and bis (aminomethyl) cyclohexane. A diamide compound obtained by combining these is used in the present invention. A diamide compound obtained from a diamine composed mainly of a fatty acid having 8 to 30 carbon atoms and mainly ethylenediamine, or a diamide compound obtained from a fatty acid mainly composed of montanic acid and a diamine having 2 to 10 carbon atoms is preferred.

  The diester compound is obtained from a fatty acid having 8 to 30 carbon atoms and a diol having 2 to 10 carbon atoms. When the fatty acid has 8 or more carbon atoms and the diol has 2 or more carbon atoms, an effect of preventing whitening can be expected. Further, when the fatty acid has 30 or less carbon atoms and the diol has 10 or less carbon atoms, uniform dispersion in the mixed resin B is good. The fatty acid may have a side chain or a double bond, but a linear saturated fatty acid is preferred.

  Examples of the fatty acid component of the diester compound include stearic acid (C18), eicoic acid (C20), behenic acid (C22), montanic acid (C28), triacontanoic acid (C30), and the like. Examples of the diol component of the diester compound include ethylene glycol, propanediol, butanediol, hexanediol, xylylene glycol, and cyclohexanedimethanol. A diester compound obtained by combining these is used in the present invention. Particularly preferred are diester compounds obtained from fatty acids composed mainly of montanic acid and diols composed mainly of ethylene glycol and / or 1,3-butanediol.

  The addition amount of the diamide compound and / or diester compound is preferably 0.005 to 1.0 part by weight, more preferably 0.05 to 0.5 part by weight, particularly preferably 100 parts by weight of the total amount of the barrier layer. Is 0.12 to 0.5 parts by weight. Addition of 0.005 part by weight or more with respect to 100 parts by weight of the total amount can be expected to prevent whitening. Further, when the addition amount is 1.0 part by weight or less with respect to the total amount of 100 parts by weight, it becomes possible to keep the haze value of the resulting multilayer bottle low.

  A conventionally known mixing method can be applied to the addition of the whitening inhibitor to the barrier layer. For example, a polyamide resin pellet, a metal catalyst compound, and a whitening inhibitor may be charged into a rotating hollow container and mixed for use. Further, after producing a polyamide resin composition containing a high concentration of whitening inhibitor, it is diluted with a polyamide resin pellet containing no whitening agent at a predetermined concentration, and this is melt kneaded, continuously after melt mixing. A method of molding by injection molding or the like is employed.

  When the whitening inhibitor is used, it is possible to prevent the barrier layer from being whitened immediately after the production of the multilayer bottle. Further, it is possible to prevent the barrier layer from being whitened after the multilayer bottle is stored for a long time under the condition that the whitening does not occur or the whitening does not increase. That is, even if a whitening inhibitor is not added, it does not whiten or does not increase in whitening, for example, after long-term storage in an atmosphere at a temperature of 23 ° C. and a humidity of 50% RH, the multilayer bottle is exposed to high humidity, water or boiling water. Even if it is brought into contact with the glass or heated to a temperature higher than the glass transition temperature, whitening is suppressed as in the case immediately after molding.

The multilayer bottle of the present invention is prepared by using, for example, an injection molding machine having two injection cylinders, polyester (A) from the skin side injection cylinder, and polyamide (B) and polyester (C) blend on the core side. The multilayer preform obtained by injecting into the mold cavity from the injection cylinder through the mold hot runner is further biaxially stretch blow molded by a known method.

In general, blow molding of a multilayer preform includes conventionally known methods such as a so-called cold parison method and a hot parison method. For example, the surface of the multilayer preform is stretched in the axial direction by mechanical means such as heating to 80 to 120 ° C. and then pressing with a core rod insert, and then normally 2 to 4 MPa of high pressure air is blown and stretched in the transverse direction. For example, a method of molding, a method of crystallizing the mouth portion of the multilayer preform, heating the surface to 80 to 120 ° C., and then blow-molding in a mold of 90 to 150 ° C.

In the present invention, the preform heating temperature is preferably 90 to 110 ° C, more preferably 95 to 108 ° C. When the preform heating temperature is lower than 90 ° C., the heating becomes insufficient, and the barrier layer or the PET layer may be cold-stretched and whitened. A temperature higher than 110 ° C. is not preferable because the barrier layer crystallizes and whitens. In addition, the delamination resistance may decrease.

In the present invention, since the barrier property, moldability, etc. are excellent, the multilayer bottle has a three-layer structure of polyester (A) layer / barrier layer / polyester (A) layer, or polyester (A) layer / barrier layer / polyester ( It is preferable to have a five-layer structure of A) layer / barrier layer / polyester (A) layer.

A multilayer bottle having a three-layer structure or a five-layer structure can be obtained by further biaxially stretching blow-molding a multilayer preform having a three-layer structure or a five-layer structure by a known method. There is no particular limitation on the method for producing a multilayer preform having a three-layer structure or a five-layer structure, and a known method can be used. For example, in the step of injecting the polyester (A) constituting the innermost layer and the outermost layer from the skin side injection cylinder, and injecting the resin constituting the barrier layer from the core side injection cylinder, the polyester (A) is injected first, and then Three-layer structure (polyester (A) layer / barrier layer / polyester) by simultaneously injecting the resin constituting the barrier layer and polyester (A) and then injecting the required amount of polyester (A) to fill the mold cavity A multilayer preform (A) can be produced.

  Further, in the step of injecting the polyester (A) constituting the innermost layer and the outermost layer from the skin side injection cylinder, and injecting the resin constituting the barrier layer from the core side injection cylinder, first the polyester (A) is injected, and then By injecting the resin constituting the barrier layer alone and finally injecting the polyester (A) to fill the mold cavity, a five-layer structure (polyester (A) layer / barrier layer / polyester (A) layer / A multilayer preform of barrier layer / polyester (A) layer can be produced. The method for producing the multilayer preform is not limited to the above method.

  The thickness of the polyester (A) layer in the multilayer bottle is preferably 0.01 to 1.0 mm, and the thickness of the barrier layer is preferably 0.005 to 0.2 mm (5 to 200 μm). . Moreover, the thickness of a multilayer bottle does not need to be constant throughout the bottle, and is usually in the range of 0.2 to 1.0 mm.

  In a multi-layer bottle obtained by biaxial stretching blow molding of a multi-layer preform, gas barrier performance can be exhibited if at least the barrier layer is present in the body of the multi-layer bottle, but the barrier layer extends to the vicinity of the top end of the multi-wall bottle stopper. The gas barrier performance is even better when the is extended. In addition, when the barrier layer extends to the vicinity of the tip of the plug portion, the barrier layer preferably contains a diamide compound and / or a diester compound. Thereby, when the bottle is stored, the crystallization of the polyamide (B) proceeds, and an increase in whitening, ie, an increase in Haze, of the portion having a low draw ratio from the bottle cap portion to the shoulder portion can be suppressed.

  In the multilayer bottle of the present invention, the weight of the barrier layer is preferably 1 to 20% by weight, more preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight based on the total weight of the multilayer bottle. By setting the weight of the barrier layer in the above range, a multilayer bottle having good gas barrier properties can be obtained, and molding from a precursor, which is a precursor, into a multilayer bottle is facilitated. Moreover, Haze of a bottle falls and it can reduce a pearl-like color tone.

By setting it as a multilayer bottle, compared with the single layer blend bottle which consists of polyamide (B) and polyester (C), the intensity | strength of a bottle, such as a buckling strength of a bottle and burst strength, can be improved. Moreover, Haze can be lowered and pearl-like color tone can be reduced, which is preferable.

  The multilayer bottle of the present invention is less susceptible to delamination due to dropping or impact, and is excellent in transparency and barrier properties. Further, even when the shape includes an uneven portion and a bent portion, delamination is unlikely to occur. Therefore, the shape of the multilayer bottle is not limited to a shape having few uneven portions and a bent portion, and the degree of freedom in design is increased. The multi-layer bottles of the present invention are, for example, carbonated drinks, juices, water, milk, sake, whiskey, shochu, coffee, tea, jelly drinks, health drinks and other liquid drinks, seasonings, sauces, soy sauce, dressings, liquid soup It is suitable for storage and storage of various articles such as liquid seasonings, liquid foods such as liquid soup, liquid pharmaceuticals, skin lotions, cosmetic emulsions, hair conditioners, hair dyes, shampoos and the like.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples. The multilayer bottle was evaluated by the following method.

(1) Delamination Height Based on ASTM D2463-Procedure B, the delamination height was determined by a container drop test and evaluated. The higher the delamination height, the better the delamination resistance. First, after filling a multilayer bottle with water and capping, the multilayer bottle was dropped and the presence or absence of delamination was visually determined. The multilayer bottle was dropped vertically so that the bottom part was in contact with the floor. The drop height interval is 15 cm. There are 30 test bottles. When the result was 300 cm or more, peeling was judged as “none”.

(2) Terminal group concentration of polyamide (a) Terminal amino group concentration ([NH ₂ ] μeq / g)
0.2-0.5 g of polyamide was precisely weighed, and the polyamide was dissolved in 30 ml of a phenol / ethanol = 4/1 volume solution with stirring. After the polyamide was completely dissolved, neutralization titration with N / 100 hydrochloric acid was performed.
(B) Terminal carboxyl group concentration ([COOH] μeq / g)
0.2 to 0.5 g of polyamide was precisely weighed, and polyamide was dissolved in 30 ml of benzyl alcohol at 160 to 180 ° C. under nitrogen flow with stirring. After the polyamide was completely dissolved, it was cooled to 80 ° C. under a nitrogen stream, 10 ml of methanol was added with stirring, and neutralization titration with an aqueous N / 100 sodium hydroxide solution was performed.

(3) Number average molecular weight of polyamide The number average molecular weight (Mn) is calculated from the amino group concentration ([NH ₂ ] μeq / g) and the carboxyl group concentration ([COOH] μeq / g) of the polyamide by the following formula (A). did.
Mn = 2 × 10 ⁶ / ([NH ₂ ] + [COOH]) (A)

(4) Haze
According to JISK-7105, the bottle body was cut into 5 cm × 5 cm and measured using a measuring device (COH-300) manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Appearance of the pearl-like appearance Visually, the degree of glazing of the bottle was evaluated. The case where the pearl shape was intense was rated as x.

1. Materials The following materials were used in Examples and Comparative Examples.
(1) Polyester 1 (PET1)
Copolymerized PET resin (intrinsic viscosity = 0.8 dl / g, isophthalic acid 3.3 mol% copolymerization, sodium 5-sulfonate amount in dicarboxylic acid component = 0.1 mol%) was used. In use, a product dehydrated in a dehumidifying dryer at 150 ° C. for 6 hours was used.
(2) Polyester 2 (PET2)
Copolymerized PET resin (intrinsic viscosity = 0.8 dl / g, isophthalic acid 2.0 mol% copolymerization, sodium 5-sulfonate amount in dicarboxylic acid component = 0.45 mol%) was used. In use, a product dehydrated in a dehumidifying dryer at 150 ° C. for 6 hours was used.
(3) Polyester 3 (PET3)
Copolymerized PET resin (trade name: Unipet BK-2180, intrinsic viscosity = 0.83 dl / g, no sulfonic acid metal base) was used. In use, a product dehydrated in a dehumidifying dryer at 150 ° C. for 6 hours was used.
(4) Polyamide 1 (PA1)
A 50-liter reactor equipped with a stirrer, a condenser, a cooler, a thermometer, a dripping tank, and a nitrogen gas introduction tube was charged with 15 kg of adipic acid and 13 g of sodium hypophosphite monohydrate, and sufficiently substituted with nitrogen. Then, the temperature was raised to 180 ° C. under a small amount of nitrogen flow, and adipic acid was uniformly melted. Then, 13.6 kg of metaxylylenediamine was required for 170 minutes while stirring the system. And dripped. During this time, the internal temperature was continuously raised to 245 ° C. Water generated by polycondensation was removed from the system through a condenser and a cooler. After completion of the dropwise addition of metaxylylenediamine, the internal temperature was further raised to 260 ° C., and the reaction was continued for 1 hour. Then, the polymer was taken out from the nozzle at the bottom of the reaction can as a strand, cooled with water, and pelletized. Next, the polymer obtained by the above operation was vacuum dried at 100 ° C. for 48 hours to obtain dried and crystallized pellets. The evaluation results of the obtained polyamide are shown in Table 1.
(5) Polyamide 2 (PA2)
The compound was synthesized in the same manner as polyamide 1 except that metaxylylenediamine was changed to 13.7 kg.
(6) Polyamide 3 (PA3)
The compound was synthesized in the same manner as polyamide 1 except that metaxylylenediamine was changed to 13.75 kg.
(7) Polyamide 4 (PA4)
The compound was synthesized in the same manner as polyamide 1 except that metaxylylenediamine was changed to 13.9 kg.
(8) Polyamide 5 (PA5)
Synthesized in the same manner as polyamide 1 except that metaxylylenediamine was changed to 13.95 kg.

<Example 1>
Under the following conditions, a three-layer preform (27 g) composed of a polyester (A) layer / barrier layer / polyester (A) layer is injection molded, and after cooling, the preform is heated and biaxial stretch blow molding is performed. Got a bottle. As the resin constituting the polyester (A) layer, a polyethylene terephthalate having an intrinsic viscosity (a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio), measuring temperature 30 ° C.) of 0.75 (Japan) Unipet RT543C) was used, and the mixed resin shown in Table 2 was used as the resin (barrier resin) constituting the barrier layer. The weight of the barrier layer with respect to the total weight of the obtained multilayer bottle was 5% by weight. The evaluation results of the multilayer bottle are shown in Table 1.

(Three-layer preform shape)
Total length 95mm, outer diameter 22mm, wall thickness 4.2mm. For the production of the three-layer preform, an injection molding machine (model: M200, 4 pieces) manufactured by Meiki Seisakusho Co., Ltd. was used.
(Three-layer preform molding conditions)
Skin side injection cylinder temperature: 275 ° C
Core side injection cylinder temperature: 260 ° C
Resin channel temperature in mold: 270 ° C
Mold cooling water temperature: 15 ° C
Ratio of barrier resin in preform: 5% by weight
(Multilayer bottle shape)
Total length 223mm, outer diameter 65mm, inner volume 500ml, bottom shape is petaloid type, body has no dimples. The biaxial stretch blow molding used a blow molding machine (model: EFB1000ET) manufactured by Frontier.
(Biaxial stretch blow molding conditions)
Preform heating temperature: 108 ° C
Stretching rod pressure: 0.5 MPa
Primary blow pressure: 0.7 MPa
Secondary blow pressure: 2.5 MPa
Primary blow delay time: 0.34 sec
Primary blow time: 0.30 sec
Secondary blow time: 2.0 sec
Blow exhaust time: 0.6 sec
Mold temperature: 30 ℃

<Examples 2-8, Comparative Examples 1-2>
A multilayer bottle was obtained in the same manner as in Example 1 except that the barrier layer composition was changed to that shown in Table 2. The evaluation results of the multilayer bottle are shown in Table 2.

The resin name abbreviations shown in the table are as follows.
S6007: Polymetaxylylene adipamide (Mitsubishi Gas Chemical Co., Ltd. MX nylon S6007)

As shown in the above examples, the multilayer bottle of the present invention showed very excellent delamination resistance and transparency, whereas a bottle not satisfying the constituent requirements of the present invention exhibited delamination resistance or It was inferior in transparency.

Claims (11)

A multi-layer bottle comprising an outermost layer and an innermost layer, and at least one barrier layer located between the outermost layer and the innermost layer, wherein the outermost layer and the innermost layer comprise dicarboxylic acid containing 80 mol% or more of terephthalic acid A diamine component mainly composed of a thermoplastic polyester resin (polyester (A)) obtained by polymerizing a component and a diol component containing 80 mol% or more of ethylene glycol, and the barrier layer containing 70 mol% or more of metaxylylenediamine And a polyamide (B) obtained by polycondensation of a dicarboxylic acid component containing 70 mol% or more of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and a copolymer component having a sulfonic acid metal base A multilayer bottle comprising a blend of at least two components of polyester (C) containing The multilayer bottle according to claim 1, wherein the weight of the polyester (C) is 40 to 90% based on the weight of the barrier layer. The multilayer bottle according to claim 1, wherein the polyamide (B) has a number average molecular weight of 10,000 to 30,000. The multilayer bottle according to claim 1, wherein the copolymerization component having a sulfonic acid metal base is 5-sodium sulfoisophthalic acid. The multilayer bottle according to claim 1, wherein the polyester (C) contains 0.1 to 1 mol% of 5-sodium sulfoisophthalic acid. The multilayer bottle according to claim 1, wherein the melt viscosity ratio of the polyamide (B) and the polyester (C) is 0.4 to 1. The barrier layer is obtained by molding a multilayer structure pellet in which polyamide (B) and polyester (C) have a multilayer structure, and polyamide (B) is a core layer and polyester (C) is a skin layer. The multilayer bottle according to claim 1. The multilayer bottle according to claim 1, wherein the barrier layer contains 0.005 to 1.0 part by weight of a diamide compound and / or a diester compound with respect to 100 parts by weight of the total amount of the barrier layer. The multilayer bottle according to claim 1, having a three-layer structure of polyester (A) layer / barrier layer / polyester (A) layer. The multilayer bottle according to claim 1, which has a five-layer structure of polyester (A) layer / barrier layer / polyester (A) layer / barrier layer / polyester (A) layer. The multilayer bottle according to claim 1, wherein the weight of the barrier layer is 1 to 20% by weight based on the total weight of the multilayer bottle.