JP2005082236A - Coinjection draw/blow molded container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer container, which retains the properties of a conventional multilayer container, such as a gas barrier property, and has a superior impact separation resistance. <P>SOLUTION: The multilayer container is formed through a coinjection draw/blow molding process, and consists of a layer of thermoplastic polyester (A) and a layer of ethylene-vinyl alcohol copolymer resin composition (B). The ethylene-vinyl alcohol copolymer resin composition (B) contains a compound containing an ionic functional group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a container having excellent gas barrier properties such as oxygen and carbon dioxide gas, gasoline barrier properties, moisture proofing properties, aroma retention properties, flavor barrier properties, and impact peel resistance, and a good appearance.

  Thermoplastic polyester (hereinafter abbreviated as PES) containers obtained by the stretch blow molding method are excellent in various properties such as transparency, mechanical properties, and flavor barrier properties. It is used in a wide range of fields because it has little risk of elution of additives and is excellent in hygiene and safety. In particular, a multilayer container combining PES and an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) having a good gas barrier property provides a container having a good appearance with a simple apparatus, and PES and EVOH. In order to improve the impact resistance and transparency, which are expected to be expanded as containers for beverages, foods, cosmetics, etc. Various proposals have also been made.

  For example, it is known that a multilayer container made of PES and partially saponified EVOH and obtained by co-injection stretch blow molding has excellent impact resistance and transparency (see, for example, Patent Document 1). The multi-layer container was epoch-making in that it had sufficient impact peel resistance despite the fact that no adhesive resin was used between PES and EVOH. However, in the multilayer container described above, it has been found that depending on the shape of the container or the filling, the impact peel resistance may be insufficient, and further improvement has been demanded.

JP 11-348194 A

  An object of the present invention is to provide a container that maintains the characteristics of a conventional multilayer container such as gas barrier properties and is excellent in impact peel resistance.

  The above object is a co-injection stretch blow-molded container comprising a thermoplastic polyester (A) layer and an ethylene-vinyl alcohol copolymer resin composition (B) layer, wherein the ethylene-vinyl alcohol copolymer resin composition is This is achieved by a co-injection stretch blow molded container characterized by containing a compound containing an ionic functional group.

  In a preferred embodiment, the compound containing an ionic functional group is an ethylene-vinyl alcohol copolymer containing an ionic functional group.

  The co-injection stretch blow molded container of the present invention is excellent in gas barrier properties such as oxygen and carbon dioxide, gasoline barrier properties, moisture resistance, aroma retention, flavor barrier properties, impact peel resistance, good appearance, beverage, Used as a container for food, cosmetics, etc., and as a fuel container for gasoline tanks.

Hereinafter, the present invention will be described in detail.
The co-injection stretch blow molded container of the present invention contains at least one PES (A) layer and EVOH resin composition (B) layer. When either one of the layers is missing, the effect of the present invention is not achieved. Although it does not specifically limit as a layer structure, a PES (A) layer is a layer (innermost layer) which touches the contents, and a layer (outermost layer) which touches outside air, and an EVOH resin composition (B) layer is an innermost layer and an outermost layer. The structure which each arrange | positions between these is preferable.

  The thickness ratio {(A) layer / (B) layer} in the container body of the PES (A) layer and the EVOH resin composition (B) layer is preferably in the range of 90/10 to 99/1. When the thickness ratio is smaller than 90/10, the usage amount of the more expensive EVOH resin composition (B) is increased more than necessary, which may be economically disadvantageous. On the other hand, when the thickness ratio is larger than 99/1, the gas barrier property of the container may be insufficient.

  The co-injection stretch blow molded container of the present invention may contain a layer other than the PES (A) layer and the EVOH resin composition (B) layer. For example, a recovery layer for recycling raw materials, an adhesive layer for improving impact peel resistance between the PES (A) layer and the EVOH resin composition (B) layer, a resin layer for adding further characteristics, etc. It can be included. However, from the viewpoint of transparency and production cost, and taking into consideration that it can be produced with a simple apparatus, the co-injection stretch blow molded container of the present invention comprises the PES (A) layer and the EVOH resin composition (B ) Layer only. Specific examples of the layer structure in this case include (inner layer) A / B / A (outer layer), (inner layer) A / B / A / B / A (outer layer), and the like, but are not limited thereto. is not.

  In the co-injection stretch blow molded container of the present invention, the intrinsic viscosity of PES (A) is preferably 0.70 to 0.90 dl / g, and more preferably 0.75 to 0.85 dl / g. When the intrinsic viscosity is less than 0.70 dl / g, the mechanical strength of the container may be insufficient. In addition, when the intrinsic viscosity exceeds 0.90 dl / g, the expected melt viscosity of the raw material is too high, so it is difficult to set the production conditions for stably producing the container, the productivity is low, and economically. It may be disadvantageous.

  The content of the cyclic trimer contained as a by-product in the PES (A) is preferably 0.50% by weight or less, more preferably 0.30% by weight or less based on the total weight of the PES (A). preferable. When the content of the cyclic trimer exceeds 0.50% by weight, the impact peel resistance may be insufficient. In addition, the cyclic trimer may be easily transferred to the contents.

  The low temperature crystallization temperature of PES (A) is preferably 120 to 180 ° C, more preferably 130 to 170 ° C. When the low temperature crystallization temperature is less than 120 ° C., the heat resistance of the container may be insufficient. On the other hand, when the low-temperature crystallization temperature exceeds 180 ° C., the expected melting point of the raw material is too high, so it is difficult to set the production conditions for stably producing the container, the productivity is low, and this is economically disadvantageous. There is a case.

The density of PES (A) is preferably 1.35~1.39g / cm ^3, more preferably 1.353~1.387g / cm ^3, further is 1.355~1.385g / cm ³ More preferred. When the density is less than 1.35 g / cm ³ , the mechanical strength of the container may be insufficient. Moreover, it may shrink | contract greatly at the time of hot filling and the heat | fever for a sterilization process. On the other hand, when the density exceeds 1.39 g / cm ³ , the occurrence of impact peeling of the container may increase.

  Although there is no restriction | limiting in particular as a kind of above-mentioned PES (A), For example, polyester mainly consisting of dicarboxylic acid units, such as an aromatic dicarboxylic acid unit, and diol units, such as an aliphatic diol unit, is mentioned. Among them, a polymer mainly composed of a terephthalic acid unit and an ethylene glycol unit, that is, a polymer containing ethylene terephthalate as a main component (polyethylene terephthalate, hereinafter abbreviated as PET) is from the viewpoint of mechanical properties, versatility and cost. preferable. Specifically, the total ratio (mol%) of the terephthalic acid unit and the ethylene glycol unit is preferably 70 mol% or more with respect to the total number of moles of all structural units constituting the PES (A). 90 mol% or more is more preferable. When the said ratio is less than 70 mol%, the crystallinity of PES (A) may fall, the mechanical strength of a container may become insufficient, or heat shrinkability may become large.

  In the above case, the PES (A) contains a bifunctional compound unit other than the terephthalic acid unit and the ethylene glycol unit as necessary, as long as the mechanical properties, heat resistance, etc. of the container are not significantly impaired. Also good. The content ratio (mol%) is preferably 30 mol% or less, and more preferably 10 mol% or less with respect to the total number of moles of all structural units constituting PES (A). Examples of such a bifunctional compound unit include an aliphatic compound unit, an alicyclic compound unit, and an aromatic compound unit. These may be any of a dicarboxylic acid unit, a diol unit and a hydroxycarboxylic acid unit. Moreover, the said bifunctional compound unit may contain only 1 type, and may contain 2 or more types.

  Among the bifunctional compound units that may be contained in PES (A), the aliphatic compound units include aliphatic dicarboxylic acid units derived from malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, etc .; 10 -Aliphatic hydroxycarboxylic acid units derived from hydroxyoctadecanoic acid, lactic acid, hydroxyacrylic acid, 2-hydroxy-2-methylpropionic acid, hydroxybutyric acid, etc .; trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, And aliphatic diol units derived from methylpentanediol, diethylene glycol and the like.

  In addition, as the alicyclic compound unit, an alicyclic dicarboxylic acid unit derived from cyclohexanedicarboxylic acid, norbornene dicarboxylic acid, tricyclodecanedicarboxylic acid, etc .; hydroxymethylcyclohexanecarboxylic acid, hydroxymethylnorbornenecarboxylic acid, hydroxymethyltricyclo And alicyclic hydroxycarboxylic acid units derived from decane carboxylic acid and the like; alicyclic diol units derived from cyclohexane dimethanol, norbornene dimethanol, tricyclodecane dimethanol, and the like. Among these, a cyclohexane dimethanol unit and a cyclohexane dicarboxylic acid unit are preferable from the viewpoint that the impact resistance at the time of dropping of the container is improved and the transparency is good. These units have isomers of 1,2-unit, 1,3-unit and 1,4-unit, respectively. In particular, 1,4-unit is more preferable from the viewpoint of improving impact resistance when the container is dropped.

  Furthermore, the aromatic compound units include isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium sulfoisophthalate, 2,6-naphthalenedicarboxylic acid, 1,4- Aromatic dicarboxylic acid units derived from naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, etc .; hydroxybenzoic acid, hydroxytoluic acid, hydroxynaphthoic acid, 3- (hydroxyphenyl) propionic acid, hydroxyphenylacetic acid, 3-hydroxy- Aromatic hydroxycarboxylic acid units derived from 3-phenylpropionic acid, etc .; 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, 2- {4- [2- (2-hydroxyethoxy) ethoxy] F Nil} -2- [4- (2-hydroxyethoxy) phenyl] propane, 2,2-bis {4- [2- (2-hydroxyethoxy) ethoxy] phenyl} propane, bis [4- (2-hydroxyethoxy) ) Phenyl] sulfone, {4- [2- (2-hydroxyethoxy) ethoxy] phenyl}-[4- (2-hydroxyethoxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl ] Cyclohexane, 1- {4- [2- (2-hydroxyethoxy) ethoxy] phenyl} -1- [4- (2-hydroxyethoxy) phenyl] cyclohexane, 1,1-bis [4- [2- (2 -Hydroxyethoxy) ethoxy] phenyl} cyclohexane, 2,2-bis [4- (2-hydroxyethoxy) -2,3,5,6-tetrabu Mophenyl] propane, 1,4-bis (2-hydroxyethoxy) benzene, 1- (2-hydroxyethoxy) -4- [2- (2-hydroxyethoxy) ethoxy] benzene, 1,4-bis [2- ( 2-hydroxyethoxy) ethoxy] benzene, etc .; aromatic diol units; aromatic diol units derived from bisphenol compounds, hydroquinone compounds, etc. Among these, from the viewpoint of impact resistance of the container, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane unit, bis [4- (2-hydroxyethoxy) phenyl] sulfone unit and 1,4 -Bis (2-hydroxyethoxy) benzene units are preferred. Moreover, a neopentyl glycol unit and a naphthalene dicarboxylic acid unit are preferable from the viewpoint of heat resistance of the container, and a naphthalene dicarboxylic acid unit is preferable from the viewpoint of having an ultraviolet absorbing ability. In order to sufficiently exhibit the ultraviolet absorbing ability, it is preferable that 0.1 to 15 mol% of naphthalenedicarboxylic acid units are contained with respect to all dicarboxylic acid units in PES (A), and 1.0 to 10%. More preferably, it is contained in mol%.

  PES (A) often contains diethylene glycol units by-produced during polymerization in addition to the bifunctional compound units intentionally contained as described above. The content ratio (mol%) is preferably 3 mol% or less, and more preferably 2 mol% or less with respect to the total number of moles of all structural units constituting PES (A). When the content rate of a diethylene glycol unit exceeds 3 mol%, the glass transition temperature of PES (A) falls, As a result, the heat resistance of a container may fall.

  PES (A) may contain a polyfunctional compound unit. The content ratio (mol%) is preferably 0.5 mol% or less with respect to the total number of moles of all structural units constituting PES (A). The polyfunctional compound unit is a unit derived from a polyfunctional compound having a total of three or more carboxyl groups and hydroxyl groups, and includes only units and hydroxyl groups derived from polycarboxylic acids having only three or more carboxyl groups. A unit derived from a polyalcohol compound containing at least one is also included. PES (A) may contain only one type of the polyfunctional compound unit, or may contain two or more types.

  Examples of the polyfunctional compound unit that may be contained in PES (A) include aliphatic polycarboxylic acid units derived from 1,3,5-cyclohexanetricarboxylic acid and the like; trimesic acid, trimellitic acid, 1,2,3 -Aromatic polycarboxylic acid units derived from benzenetricarboxylic acid, pyromellitic acid, 1,4,5,8-naphthalenetetracarboxylic acid, etc .; aliphatic polyalcohol units derived from trimethylolpropane, pentaerythritol, glycerin, etc .; Alicyclic polyalcohol units derived from 1,3,5-cyclohexanetriol, etc .; Aromatic polyalcohol units derived from 1,3,5-trihydroxybenzene, etc .; Aliphatic hydroxycarbons derived from tartaric acid, malic acid, etc. Acid; 4-hydroxyisophthalic acid, 3-hydroxyisophthalic acid, 2,3-dihydride Aromatic hydroxycarboxylic acids derived from xylbenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, protocatechuic acid, gallic acid, 2,4-dihydroxyphenylacetic acid, etc. Unit; and the like. Among these, units derived from trimesic acid, trimellitic acid, pyromellitic acid, trimethylolpropane, and pentaerythritol are preferable from the viewpoint of ease of production and production cost.

  When PES (A) contains a polyfunctional compound unit as described above, it may contain a monofunctional compound unit derived from a monocarboxylic acid, a monoalcohol or the like at the same time. The content ratio (mol%) is preferably 5 mol% or less with respect to the total number of moles of all structural units constituting PES (A) from the viewpoint of ease of production and production cost. % Or less is more preferable. PES (A) may contain only one type of the monofunctional compound unit, or may contain two or more types.

  Monofunctional compound units that may be contained in PES (A) include fats derived from n-octanoic acid, n-nonanoic acid, myristic acid, pentadecanoic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, etc. Group monocarboxylic acid unit; benzoic acid, o-methoxybenzoic acid, m-methoxybenzoic acid, p-methoxybenzoic acid, o-methylbenzoic acid, m-methylbenzoic acid, p-methylbenzoic acid, 2,3-dimethyl Benzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid, 3,4-dimethylbenzoic acid, 3,5-dimethylbenzoic acid, 2,4,6-trimethyl Benzoic acid, 2,4,6-trimethoxybenzoic acid, 3,4,5-trimethoxybenzoic acid, 1-naphthoic acid, 2-naphthoic acid, 2-biphenylcarboxylic acid, 1-naphtho Aromatic monocarboxylic acid units derived from lenacetic acid, 2-naphthaleneacetic acid, etc .; derived from pentadecyl alcohol, stearyl alcohol, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polytetramethylene glycol monoalkyl ether, oleyl alcohol, etc. Aliphatic monoalcohol unit derived from alicyclic monoalcohol unit derived from cyclododecanol, etc .; derived from benzyl alcohol, 2,5-dimethylbenzyl alcohol, 2-phenethyl alcohol, phenol, 1-naphthol, 2-naphthol, etc. Aromatic monoalcohol units; and the like. Among these, units derived from stearic acid, benzoic acid, 2,4,6-trimethoxybenzoic acid, 2-naphthoic acid, and stearyl alcohol are preferable from the viewpoint of ease of production and production cost.

  The PES is a generally known condensation polymerization method using a dicarboxylic acid or an ester-forming derivative thereof, a diol, and, if necessary, a bifunctional compound, a polyfunctional compound, a monofunctional compound, or the like exemplified above as a raw material. It is manufactured by adopting. For example, the PES is produced by mixing the above raw materials and first causing esterification or transesterification, then melt polycondensation, and solid phase polymerization as necessary.

  As the dicarboxylic acid and diol in this case, terephthalic acid and ethylene glycol are preferable as described above. The bifunctional compound that may be contained other than that is also as described above. Among the bifunctional compounds other than terephthalic acid and ethylene glycol, neopentyl glycol, cyclohexane dimethanol, cyclohexane dicarboxylic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (especially 2,6) from the viewpoint of easy production. -Naphthalenedicarboxylic acid), 4,4'-biphenyldicarboxylic acid, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxyethoxy) phenyl] sulfone and 1,4 -Bis (2-hydroxyethoxy) benzene is preferred, and among these, from the viewpoint of cost, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (particularly 2,6-naphthalenedicarboxylic acid) and 4,4'-biphenyldicarboxylic acid Acid is more preferred. On the other hand, considering the characteristics of the obtained PES, isophthalic acid is preferable from the viewpoint of moldability and suppression of crystallization at the time of molding, and 2,2-bis [4- (2-Hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxyethoxy) phenyl] sulfone and 1,4-bis (2-hydroxyethoxy) benzene are preferred.

  When ethylene glycol is used as a raw material diol, as described above, diethylene glycol by-produced during the polymerization is introduced into the main chain, resulting in coloration of the obtained PES, and reduced heat resistance and mechanical strength. There is a case. In order to prevent this, in the esterification reaction, transesterification reaction and melt polycondensation, it is preferable to use 0.001 to 0.5% by weight of a by-product inhibitor of diethylene glycol based on the weight of the raw dicarboxylic acid. . Examples of the by-product inhibitor include tetraalkylammonium hydroxides such as tetraethylammonium hydroxide; organic amines such as triethanolamine and triethylamine; and the like.

  The EVOH resin composition (B) used in the co-injection stretch blow molded container of the present invention is characterized by containing a compound containing an ionic functional group. The EVOH resin composition (B) may be a mixture of EVOH and a polymer compound (including EVOH) containing an ionic functional group, or a low molecular compound containing EVOH and an ionic functional group; It may be a mixture of Moreover, the case where the EVOH resin composition (B) is made of an ethylene-vinyl alcohol copolymer containing an ionic functional group is also included in the present invention.

  The ethylene content of EVOH contained in the EVOH resin composition (B) is preferably 5 to 60 mol%. When the ethylene content is less than 5 mol%, gas barrier properties under high humidity may be insufficient. The ethylene content is more preferably 15 mol% or more, and even more preferably 20 mol% or more. Moreover, when ethylene content exceeds 60 mol%, gas barrier property may become inadequate. The ethylene content is more preferably 50 mol% or less, and even more preferably 45 mol% or less.

  The saponification degree of the vinyl ester component of EVOH is preferably 90% or more, more preferably 96% or more, and even more preferably 98.5% or more. When the degree of saponification is less than 90%, the gas barrier property under high humidity may be insufficient.

  The ethylene content and saponification degree of EVOH can be determined by a nuclear magnetic resonance (NMR) method.

  When the above EVOH is composed of a blend of two or more types of EVOH having at least one different ethylene content and saponification degree, the average value calculated from the blending weight ratio is the ethylene content and saponification degree. .

  The EVOH may contain a small amount of a monomer other than ethylene and vinyl alcohol as a copolymerization component as long as the object of the present invention is not impaired. Examples of such monomers include propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene, 1-octene and other α-olefins; vinyltrimethoxysilane, vinyltriethoxysilane, Examples thereof include vinylsilane compounds such as vinyltri (β-methoxy-ethoxy) silane and γ-methacryloxypropyltrimethoxysilane; alkylthiols and the like.

  The melt index of EVOH (under 190 ° C. and 2160 g load, based on JIS K7210) is preferably 0.1 to 10 g / 10 min. If the melt index is less than 0.1 g / 10 min, the melt viscosity of the raw material is too high, and it is difficult to set production conditions for stable production, resulting in low productivity, which may be economically disadvantageous. The melt index is more preferably 0.5 g / 10 min or more. On the other hand, if the melt index exceeds 10 g / 10 min, the mechanical properties may be insufficient, cracks may occur due to drop impact or the like, and the gas barrier properties of the container may deteriorate. The melt index is more preferably 8 g / 10 min or less, and even more preferably 6 g / 10 min or less.

  The EVOH can be obtained by saponifying a copolymer composed of ethylene and vinyl ester using an alkali catalyst or the like. A typical vinyl ester is vinyl acetate, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. At this time, EVOH having a desired melting point can be obtained by adjusting the ethylene content and the degree of saponification.

  In the copolymerization, monomers other than ethylene and vinyl ester can be copolymerized as long as the object of the present invention is not inhibited as described above. Among them, EVOH containing a vinylsilane compound as a copolymerization component in the range of 0.0002 to 0.2 mol% has a good balance of melt viscosity in the case of co-injection molding with PES, which will be described later, and produces a homogeneous molded product. Is possible. Here, as a vinylsilane type compound, vinyltrimethoxysilane and vinyltriethoxysilane are preferable. As for content of a vinylsilane compound, 0.001-0.15 mol% is more preferable, and 0.005-0.1 mol% is still more preferable.

  In the co-injection stretch blow molded container of the present invention, the EVOH resin composition (B) contains a compound containing an ionic functional group. By using such EVOH resin composition (B), the impact resistance of the resulting container is improved. Although the reason is not clear, it is considered that the impact peel resistance is improved by the ionic interaction effect between the thermoplastic polyester (A) layer and the EVOH resin composition (B) layer.

  In the present invention, the ionic functional group is a group that exhibits ionicity (anionic, cationic, amphoteric) in a solution. The ionic functional group contained in the EVOH resin composition (B) may be only one type or two or more types.

  Examples of the anionic group include sulfonic acid, sulfonate, sulfate, sulfate ester, phosphoric acid, phosphate, carboxylic acid, carboxylate, and the like, and these acids and bases may be contained at the same time. Good. A sulfonic acid and a carboxylic acid or a salt thereof are preferable from the viewpoint of excellent impact peel resistance improving effect, and a sulfonic acid or the salt is particularly preferable.

  Examples of the cationic group include amines and salts thereof, quaternary ammonium salts, phosphonium salts, sulfonium salts and the like. In particular, a quaternary ammonium salt is preferable because it has a large effect of improving impact resistance. Examples of the amphoteric group include aminocarboxylate (betaine type), aminosulfonate (sulfobetaine type), aminosulfate ester salt (sulfate betaine type), and the like.

  The content of the ionic functional group is appropriately selected within the range in which the effect of improving the impact peel resistance is exhibited, but is 0.2 μmol to 20 mmol, that is, 0.2 μmol / gram with respect to 1 g of EVOH resin composition (B). g to 20 mmol / g is preferred, 0.4 μmol / g to 10 mmol / g is more preferred, 0.6 μmol / g to 5 mmol / g is even more preferred, and 0.6 μmol / g to 1 mmol / g is most preferred. If it is less than 0.2 μmol / g, the effect of improving the impact peel resistance is small, and if it exceeds 20 mmol / g, the gas barrier property becomes poor, which is not preferable.

  The polymer compound containing the ionic functional group is not particularly limited, and examples thereof include compounds containing the following monomers: itaconic acid, methacrylic acid, acrylic acid, maleic anhydride, etc. Unsaturated carboxylic acids, salts thereof, partial esters thereof, nitriles thereof, amides thereof, anhydrides thereof; 2- (meth) acrylamide-2-methylpropanesulfonic acid, styrenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, etc. Unsaturated sulfonic acids or salts thereof; amino group-containing (meth) acrylamide monomers such as aminopropylacrylamide and methacrylamide; amino group-containing (meth) acrylates such as aminoethyl acrylate and methacrylate or salts thereof; trimethylacrylamidepropylammonium chloride, Triethylmetac Quaternary ammonium salt-containing monomers such as yl ethyl ammonium bromide. Among these, trimethylacrylamidopropylammonium chloride, triethylmethacryloylethylammonium bromide, and the like are preferable because the polymer compound is less colored. On the other hand, as monomers constituting the polymer main chain, ethylene, propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene, 1-octene and other α-olefins; vinyl chloride, vinyl acetate, styrene And the like, and one kind or two or more kinds of them are used.

  Further, the low molecular compound containing an ionic functional group is not particularly limited, but includes the following compounds: inorganic acids such as hydrochloric acid, acetic acid, sulfuric acid, nitric acid, phosphoric acid, and salts thereof Organic carboxylic acids such as stearic acid and neodecanoic acid and salts thereof; organic sulfonic acids such as benzenesulfonic acid and salts thereof; ammonium compounds such as tetramethylammonium;

  When producing an EVOH resin composition (B) containing a high molecular compound or low molecular compound other than EVOH as the compound containing an ionic functional group, it is preferable to consider miscibility with EVOH. These miscibility may affect gas barrier properties, gasoline barrier properties, transparency, cleanliness, impact peel resistance improvement effect, mechanical properties, and the like.

  The method for mixing and molding the components of the resin composition of the present invention is not particularly limited. The order of mixing the components is not particularly limited. In addition, each component of these compositions may be melt-blended and pelletized before use for molding, or dry blended for direct molding.

  As a means for blending and kneading each of the above components, a method in which each component is dissolved using a solvent and the solvent is evaporated after mixing; a soluble component is dissolved using a solvent and mixed with an insoluble component Examples include a method of evaporating the solvent later; and a method of melting and kneading at a temperature in the range of 50 ° C. to 300 ° C. (melt blending method). The melt blending method is preferable from the viewpoint of process simplicity and cost, but is not particularly limited. Examples of the means used for melt blending include a ribbon blender, a high speed mixer, a kneader, a mixing roll, an extruder, a Banbury mixer, an inactive mixer, and the like.

  On the other hand, when the compound containing an ionic functional group is an ethylene-vinyl alcohol copolymer containing an ionic functional group, the intended EVOH resin composition can be used without considering the miscibility as described above. A thing (B) can be obtained.

  As EVOH containing an ionic functional group, those in which an ionic functional group is randomly introduced into EVOH or an ionic group is introduced at the end of EVOH are preferably used.

  The method for producing EVOH containing an ionic functional group is not particularly limited. For example, radical copolymerization of a monomer containing an ionic functional group with ethylene and a vinyl ester, and then the vinyl ester in the obtained copolymer A method of saponifying units to convert them to vinyl alcohol units, a method of radical copolymerization with ethylene and vinyl ester, a method of introducing an ionic group-containing component into a copolymer obtained by saponification, or ethylene-vinyl Examples thereof include a method in which an ionic group-containing component is subjected to an addition reaction with an ester copolymer, and then a vinyl ester unit in the copolymer is saponified and converted to a vinyl alcohol unit.

  Examples of the addition reaction that can be applied for the above purpose include Michael addition reaction of an ionic functional group-containing vinyl monomer to the hydroxyl group, acetalization or ketalization with an ionic group-containing aldehyde or ketone, Addition of carboxylic acid anhydride, esterification with sulfuric acid, and the like. Moreover, the radical addition reaction etc. of an ionic group containing monomer with low radical homopolymerizability, such as maleic anhydride, are mentioned.

  Further, a compound containing an active group such as an alcohol, aldehyde or thiol having a sulfonic acid group or a salt thereof, a carboxyl group or a salt thereof, an ammonium group or the like as a chain transfer agent, and a monomer containing ethylene and a vinyl ester Method of copolymerization and subsequent saponification of vinyl ester units, and saponified copolymer of ethylene and vinyl ester-containing monomers containing sulfonic acid groups or salts thereof, carboxyl groups or salts thereof, ammonium groups, etc. It can also be produced by a method in which the compound to be introduced is introduced by a chemical reaction. Among these methods, an ionic group is introduced economically and efficiently at the end, and a method for obtaining modified EVOH exhibiting excellent stability as a dispersion stabilizer includes a sulfonic acid group or a salt thereof, a carboxyl group. Alternatively, a method in which ethylene and a monomer containing a vinyl ester are copolymerized in the presence of a thiol having a salt or an ammonium group thereof and then saponified is preferable.

  As the ionic functional group-containing monomer, those capable of radical homopolymerization or radical copolymerization having an ionic functional group or a functional group convertible to an ionic functional group can be used. As an example thereof, there may be mentioned a monomer containing an ionic functional group that constitutes the polymer compound containing the ionic functional group described above.

  The EVOH resin composition (B) contains a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, a filler, and other resins (polyamide, polyolefin, etc.) as long as the object of the present invention is not obstructed. You may go out.

  First, a container precursor (bottomed parison) having a multilayer structure is produced using the above PES and EVOH resin composition. A bottomed parison usually uses a molding machine having two injection cylinders, and performs a single clamping operation on a single mold, and melts the PES and the EVOH resin composition from the respective injection cylinders. It is obtained by alternately injecting at different timings or simultaneously injecting from the concentric nozzles, or by continuously performing these operations. For example, (1) A method of injecting PES for inner and outer layers first, and then injecting an EVOH resin composition to be an intermediate layer to obtain a bottomed parison having two types and three layers of A / B / A, (2) First, PES for the inner and outer layers is injected, then the EVOH resin composition is injected, and at the same time or thereafter, the PES that becomes the central layer is injected again, and two types of A / B / A / B / A A general manufacturing method of a bottomed parison in which the inner layer is completely enclosed in the PES layer, such as a method of obtaining a bottomed parison having a five-layer structure, is employed.

  As conditions for injection molding of a bottomed parison, the injection temperature of PES is preferably 250 to 330 ° C, more preferably 270 to 320 ° C, and even more preferably 280 to 310 ° C. When the injection temperature of PES is less than 250 ° C., unmelted material is mixed into the obtained bottomed parison, which may lead to problems such as a fish eye that impairs the appearance and insufficient mechanical strength of the container. . Furthermore, in extreme cases, the screw torque increases and causes a failure of the molding machine. On the other hand, when the injection temperature of PES exceeds 330 ° C., the decomposition of PES becomes remarkable, the mechanical strength of the container is insufficient, and there is a possibility that problems such as the deterioration of the properties of the contents by a decomposition gas such as acetaldehyde may occur. is there. Further, the annular trimer that is generated at the same time may cause the mold to become very dirty, and the appearance of the container may be impaired.

  Moreover, it is preferable that the injection temperature of EVOH resin composition is 170-250 degreeC, 180-240 degreeC is more preferable, 190-230 degreeC is still more preferable. When the injection temperature of the EVOH resin composition is less than 170 ° C., an unmelted material is mixed into the obtained bottomed parison, which may become fish eyes and impair the appearance. Furthermore, in extreme cases, the screw torque increases and causes a failure of the molding machine. On the other hand, when the injection temperature of the EVOH resin composition exceeds 250 ° C., the EVOH resin composition is significantly decomposed or gelled, which may cause problems such as poor appearance of the container and a decrease in gas barrier properties. Furthermore, in an extreme case, injection molding becomes impossible due to the generation of a gelled product.

  Furthermore, the temperature of the hot runner part into which the PES and EVOH resin composition flows is preferably in the range of 220 to 300 ° C, more preferably 240 to 280 ° C, and even more preferably 250 to 270 ° C. When the temperature of the hot runner portion is less than 220 ° C., PES may solidify at the hot runner portion and it may be difficult to form. On the other hand, when the temperature of the hot runner part exceeds 300 ° C., the EVOH resin composition is significantly decomposed or gelled, and there is a possibility that problems such as poor appearance of the container and deterioration of gas barrier properties may occur. Furthermore, in an extreme case, injection molding becomes impossible due to the generation of a gelled product.

  In injection molding, for example, the PES (A) layer and the EVOH resin composition (B) of the resulting container are appropriately adjusted by appropriately adjusting the injection speed and injection amount of the PES and the injection speed and injection amount of the EVOH resin composition. ) The thickness ratio of the container body of the layer can be controlled.

  The mold temperature is preferably in the range of 0 to 70 ° C, more preferably 5 to 50 ° C, and even more preferably 10 to 30 ° C. When the mold temperature is less than 0 ° C., the appearance of the obtained bottomed parison may be damaged by the condensation of the mold. On the other hand, when the mold temperature exceeds 70 ° C., the crystallization of the PES and EVOH resin composition proceeds in the bottomed parison obtained, transparency is impaired, and uniform stretching becomes difficult in the subsequent stretch blow molding. There is a possibility that problems such as a decrease in formability and a decrease in impact peelability of the resulting container may occur.

  The body thickness of the bottomed parison is preferably 2 to 5 mm in total layer thickness, and the EVOH resin composition layer is preferably 20 to 500 μm in total. If the thickness of the EVOH resin composition layer is increased more than necessary, the stretchability may deteriorate in the subsequent stretch blow molding.

  The bottomed parison thus obtained is stretch blow molded to produce the co-injection stretch blow molded container of the present invention. The bottomed parison is directly heated in a high temperature state or is reheated to 75 to 150 ° C. with a heating element such as a block heater or an infrared heater, and then sent to the stretch blow process, and is 1 to 5 times in the longitudinal direction. After being stretched, it is stretch blow molded 1 to 4 times with compressed air or the like. The temperature of the bottomed parison during heating is more preferably 85 to 140 ° C, still more preferably 90 to 130 ° C, and still more preferably 95 to 120 ° C. When the temperature of the bottomed parison at the time of heating exceeds 150 degreeC, crystallization of PES advances and there exists a possibility that the transparency of the container obtained may be impaired or the impact-proof peeling property of a container may fall. On the other hand, when the temperature is less than 75 ° C., craze is generated in the PES, and the transparency may be deteriorated due to a pearly tone.

  The total thickness of the trunk portion of the co-injection stretch blow molded container of the present invention is generally 100 μm to 3 mm, and can be properly used depending on the application.

  The co-injection stretch blow molded container of the present invention obtained by the method as described above has extremely good impact peel resistance. Among these, the container body is filled with water and placed on a 20 cm long table with an angle of 90 ° from a height of 50 cm so that the corner of the table hits the center of the container body. It is preferable that the ratio of the container that causes peeling when the part is horizontally dropped and is naturally dropped only once is 20% or less.

  The haze in the container body of the co-injection stretch blow molded container of the present invention is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less. When haze exceeds 5%, the commercial value as a container will fall remarkably.

  The co-injection stretch blow molded container of the present invention is suitable for storing various contents over a long period of time, such as carbonated drinks, various drinks such as beer and wine, food and cosmetic containers, and gasoline tanks and the like. Useful as a fuel container.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the examples, analysis and evaluation were performed as follows.

(Analysis of PES)
(1) Content of each structural unit:
¹ H-NMR measurement (using “JNM-GX-500 type” manufactured by JEOL Ltd.) was performed using deuterated trifluoroacetic acid as a solvent, and the content of each structural unit was calculated from the obtained spectrum.

(2) Terminal carboxyl group concentration:
0.2 g of a sample was dissolved in 10 ml of benzyl alcohol heated to 215 ° C., 10 ml of chloroform was added after dissolution, and titrated with a benzyl alcohol solution of caustic soda to obtain a terminal carboxyl group concentration.

(3) Cyclic trimer content:
100 mg of a sample was dissolved in 2 ml of chloroform / 1,1,1,3,3,3-hexafluoro-2-propanol (volume ratio 1/1), and further diluted with 8 ml of chloroform. Further, acetonitrile was added to precipitate the polymer component so that the volume of the solution became 100 ml, and the polymer component was removed by filtration. The obtained filtrate was subjected to high performance liquid chromatography (column: ODS-II, manufactured by Chemco Co., Ltd., detector: ultraviolet / visible detector and refractive index detector) using an aqueous 75% by volume acetonitrile solution as an eluent. The content (% by weight) of the cyclic trimer was determined.

(4) Intrinsic viscosity:
The measurement was performed at 30 ° C. using an Ubbelohde viscometer (“HRK-3” manufactured by Hayashi Seisakusho) using a mixed solvent of equal weight of phenol and tetrachloroethane as a solvent.

(5) Low temperature crystallization temperature:
A differential scanning calorimeter (DSC) RDC220 / SSC5200H type manufactured by Seiko Instruments Inc. was used as an apparatus, and indium and lead were used as temperature calibration samples. After melting and holding the sample at 300 ° C. for 5 minutes, the sample was immersed in liquid nitrogen for a few seconds, quenched, and further kept at room temperature. Next, the sample was heated at a rate of 20 ° C./min, and the low temperature crystallization temperature was determined from the obtained DSC chart.

(6) Density:
Using a density gradient tube filled with an n-hexane / carbon tetrachloride mixed liquid kept at 25 ° C., the density of a film-like sample of 0.5 cm × 0.5 cm was measured.

(7) Glass transition temperature and melting point:
The measurement was performed according to JIS K7121, using the same apparatus and temperature calibration sample as above. The sample was held at 280 ° C. for 5 minutes, then cooled to 30 ° C. at a temperature drop rate of 100 ° C./min, and held for another 5 minutes. Next, the sample was heated at a rate of 10 ° C./min, and the glass transition temperature and melting point were determined from the obtained DSC chart. Here, the glass transition temperature refers to the midpoint glass transition temperature (Tmg) referred to in the above JIS, and the melting point refers to the melting peak temperature (Tpm) referred to in the above JIS.

(Analysis of EVOH)
(8) Ethylene content and saponification degree of EVOH:
1H-NMR measurement (using “JNM-GX-500 type” manufactured by JEOL Ltd.) was performed using deuterated dimethyl sulfoxide as a solvent, and ethylene content and saponification degree were calculated from the obtained spectrum.
(9) Ionic functional group content ratio:
A trace total nitrogen analyzer (using “TN-10 type” manufactured by Mitsubishi Kasei Co., Ltd.) was used, and the content of sodium 2-acrylamido-2-methylpropanesulfonate unit was calculated from the obtained nitrogen content.

(10) Melt index:
It measured using melt indexer L244 (made by Takara Kogyo Co., Ltd.). The sample was filled in a cylinder having an inner diameter of 9.55 mm and a length of 162 mm, melted at 190 ° C., and then uniformly loaded with a plunger having a weight of 2160 g and a diameter of 9.48 mm. The outflow rate (g / 10 minutes) of EVOH extruded from a 1 mm orifice was measured and used as the melt index.

(Evaluation of container)
(11) Impact peeling occurrence rate:
After filling the container with water and sealing it under normal pressure, from the height of 50 cm onto a 20 cm long table with an angle of 90 °, so that the corner of the table hits the center of the container body The container body was horizontally dropped and allowed to fall only once. A test was conducted on 100 containers, and the delamination rate (Rd) was calculated from the number of containers (Nd) that caused delamination using the following formula.
Rd (%) = (Nd / 100) × 100

(12) Haze value (cloudiness value):
Using the Poick integrating sphere type light transmittance / total light reflectometer (Murakami Color Research Laboratory "HR-100 type") at four locations where the center of the container body is divided into four on the circumference, ASTM D1003- The internal haze value was measured according to No. 61, and the average value was taken as the haze value (cloudiness value) of the container.

(13) Oxygen transmission rate:
In the form of a container, after adjusting the temperature and humidity to 20 ° C.-65% RH on the outside of the container and 20 ° C.-100% RH on the inside of the container, an oxygen transmission rate measuring device (OX-TRAN-10 / manufactured by Modern Control Co., Ltd.) 50A) was used to measure the oxygen transmission rate per container (ml / container · day · atm).

As PES, the contents of terephthalic acid unit, ethylene glycol unit and diethylene glycol unit were 50.0 mol%, 48.9 mol% and 1.1 mol%, respectively, the terminal carboxyl group concentration was 22 μeq / g, PET1 having a content of 0.32% by weight, an intrinsic viscosity of 0.83 dl / g, a low-temperature crystallization temperature, a glass transition temperature and a melting point of 155 ° C., 80 ° C. and 252 ° C., respectively, and a density of 1.369 g / cm ³ It was used.

  As the EVOH resin composition (B), a sodium 2-acrylamido-2-methylpropanesulfonate unit was randomly copolymerized with 1.1 mol% of the EVOH component, an ethylene content of 32 mol%, and a saponification degree of 99.5. %, EVOH1 having a melt index (190 ° C.−2160 g load) of 4.3 g / 10 min was used. (Ionic functional group content ratio: 0.27 mmol / g)

  Using PET1 and EVOH1, co-injection molding was performed by a KORTEC / HUSKY co-injection molding machine (four SL160 molds) to form a bottomed parison having two types and three layers of PET1 / EVOH1 / PET1. At this time, the PET-side injection machine temperature is 280 ° C., the EVOH-side injection machine temperature is 210 ° C., the hot runner block portion where PET1 and EVOH1 merge is 270 ° C., the injection mold core temperature is 10 ° C., the injection mold cavity The temperature was 10 ° C. Further, the injection speed and the injection amount were adjusted so that the thickness ratio of the PES layer and the EVOH layer in the container was 95/5. When this parison was visually observed, there was no coloration, no streak was observed, and it was in a good state.

  Then, using a CRUPP CORPLAST MASCHINENBAU stretch blow molding machine (LB01 type 530 mL 1 piece), the surface temperature of the bottomed parison is heated to 105 ° C., stretch blow molding is performed, and two types and three layers of co-injection stretch blow A molded container was obtained. The impact peeling occurrence rate, haze, and oxygen transmission rate of this container were measured. Furthermore, when this container was visually observed, no streaks, gels or bubbles were observed, and the container had a good appearance. These evaluation results are shown in Table 1.

Comparative Example 1
In Example 1, EVOH 2 having an ethylene content of 32 mol%, a saponification degree of 99.5%, and a melt index (190 ° C.-2160 g load) of 4.8 g / 10 minutes was used instead of EVOH 1. In the same manner as in No. 1, two types and three layers of bottomed parison were molded. When this parison was visually observed, there was no coloration, no streak was observed, and it was in a good state.

  Thereafter, stretch blow molding was performed in the same manner as in Example 1 to obtain a two-kind three-layer co-injection stretch blow-molded container. When this container was visually observed, no streaks, gels or bubbles were observed, and the container had a good appearance. This container was evaluated in the same manner as in Example 1. The results are shown in Table 1.

From the above results, it can be seen that the container of Example 1, which is an example of the co-injection stretch blow molded container of the present invention, is excellent in impact peel resistance, excellent in transparency, and excellent in appearance. On the other hand, such an effect cannot be obtained in the container of Comparative Example 1 that does not satisfy the above requirements.

Claims (2)

A co-injection stretch blow molded container comprising a thermoplastic polyester (A) layer and an ethylene-vinyl alcohol copolymer resin composition (B) layer, wherein the ethylene-vinyl alcohol copolymer resin composition (B) is an ion. A co-injection stretch blow-molded container comprising a compound containing a functional functional group. The co-injection stretch blow-molded container according to claim 1, wherein the compound containing an ionic functional group is an ethylene-vinyl alcohol copolymer containing an ionic functional group.