JP2011102008A - Multilayer structure, stretched multilayered structure, multilayer hollow container, and manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas barrier molded body excellent in stretchability and appearance. <P>SOLUTION: A multilayer structure and a stretched multilayer structure each have a saponified ethylen-vinylester copolymer (A) layer having 1, 2-diol structure units shown by general formula (1) and a polyolefinic resin layer (B) containing an amide compound and is constituted by arranging the (B) layer on at least one face of the layer (A). In general formula (1), R1, R2, and R3 each independently shows a hydrogen atom or an organic group, X shows a single bond or a joining chain, R4, R5, and R6 each independently shows a hydrogen atom or an organic group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer structure in which a polyolefin resin layer is provided on at least one side of a saponified ethylene-vinyl ester copolymer (hereinafter sometimes referred to as EVOH resin) layer, and in particular, a side chain. A multi-layer structure, a stretched multi-layer structure, a multi-layer hollow container, and a production thereof, wherein a polyolefin resin layer containing a specific amide compound is provided on at least one side of a special EVOH resin layer having a 1,2-diol bond structure It is about the method.

Plastic hollow containers (for example, bottles and the like) are light and excellent in strength, and can be easily formed into an arbitrary shape, and are therefore used as containers for beverages and medicines.
However, when transporting a large amount of hollow containers from container manufacturers to users (for example, when transporting hollow containers from a hollow container manufacturer to a beverage / pharmaceutical manufacturer, etc.), the filling rate of the hollow containers is lowered and transported. Inefficient, leading to increased transportation costs.
Therefore, attention is paid to a method in which a small preform (preform) that is a precursor of a hollow container is first manufactured, transported to the vicinity of the place of use, and then molded into a final hollow container. In this case, an injection stretch blow molding method is useful in which a preform is produced by injection molding, and then the preform is heated and stretch blow molded to obtain a molded product.
In such a case, since the filling rate of the preform is very high during transportation, transportation efficiency is improved and transportation costs are reduced.

As a molding material for a hollow container obtained by such injection stretch blow molding, polyester resins and polyolefin resins are usually used, and polyester resins (for example, polyethylene terephthalate) are widely used from the viewpoint of price and mechanical properties. However, polyolefin resins have attracted attention because they can reduce the weight of the container and fill the contents with hot fill.
On the other hand, since polyolefin resin has low gas barrier performance, it is useful to use an EVOH resin having excellent gas barrier properties in combination.

On the other hand, such EVOH resin blocks gas molecule permeation by abundant hydroxyl group hydrogen bonding and exhibits gas barrier properties. On the other hand, there is room for improvement in stretchability due to its high crystallinity. Therefore, in order to improve the stretchability of the EVOH resin, a technique using an EVOH resin represented by the following general formula (1) and having a 1,2-diol bond structure in the side chain is known (for example, Patent Document 1).

[In General Formula (1), R1, R2, and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bond chain, and R4, R5, and R6 each independently represent a hydrogen atom. Or an organic group is shown. ]
Such a special EVOH resin has characteristics that the crystallinity is lower than that of a normal EVOH resin, the stretchability is excellent, and the gas barrier property is excellent.

JP 2006-096368 A

  However, when a special EVOH resin having a 1,2-diol bond structure in the side chain is laminated on a polyolefin resin layer and applied to the injection stretch blow molding method, the polyolefin resin is stretched by the special EVOH resin. Thus, there was room for improvement in stretchability (stretch ratio) and appearance (disturbance between layers due to difference in stretch speed) of the obtained molded body.

In view of the above circumstances, as a result of intensive studies, the inventors have formulated a multilayer structure excellent in stretchability and appearance when the amide compound represented by the following general formula (2) is blended with a polyolefin resin. It became possible to get.

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ]

That is, the gist of the present invention includes an EVOH resin (A) layer having a 1,2-diol structural unit represented by the following general formula (1) and an amide compound represented by the following general formula (2). A multilayer structure having a polyolefin-based resin (B) layer and having the (B) layer provided on at least one side of the (A) layer, a stretched multilayer structure obtained by stretching the multilayer structure, and a multilayer hollow container Exist.

[In General Formula (1), R1, R2, and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bond chain, and R4, R5, and R6 each independently represent a hydrogen atom. Or an organic group is shown. ]

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ]

  Further, the present invention relates to a method of producing a stretched multilayer structure by producing a multilayer structure in which a polyolefin resin layer is provided on at least one side of the EVOH resin layer, and stretching the multilayer structure. An EVOH resin (A) layer having a 1,2-diol structural unit represented by the general formula (1), wherein the polyolefin resin layer contains an amide compound represented by the following general formula (2) A method for producing a stretched multilayer structure characterized in that it is a polyolefin resin (B) layer, and the multilayer structure is produced by a co-injection molding method, and the stretch method for the multilayer structure is blow-stretching And a method for producing a multilayer hollow container, wherein the stretched multilayer container is a multilayer hollow container.

  In addition, it is known that the compound represented by the general formula (2) works as a crystal nucleating agent for polyolefin resin (for example, see JP-A-2007-46037).

When the amide compound represented by the general formula (2) is contained in the polyolefin resin, it is considered that the crystallization of the resin is promoted and many crystals of the polyolefin resin are generated. In particular, in the injection stretch blow molding method, since a preform is prepared before stretching, a large number of polyolefin resin crystals grow and are stable in the polyolefin resin layer containing the amide compound represented by the general formula (2). It is thought that exists.
Those of ordinary skill in the art expect that when such a polyolefin-based resin layer in a crystalline state is heated and stretched again, the stretching performance will not be improved, but rather will be lowered. As a result of the examination, it was found that the film has very excellent drawing performance contrary to expectations. That is, when the polyolefin resin contains the amide compound represented by the above general formula (2), it has been found that the multilayer structure in which the special EVOH resin is laminated has excellent stretching performance.

Furthermore, the stretched multilayer structure obtained by stretching the multilayer structure has an effect that it is excellent in evaluation of stretchability (stretch ratio) and appearance (disturbance between layers due to differences in stretch speed).
This is because the polyolefin resin contains the amide compound represented by the above general formula (2), so that not only the stretching performance is improved but also the stretching performance of the special EVOH resin is the same. It is presumed to approximate.

Hereinafter, although it demonstrates in detail about the structure of this invention, these show an example of a desirable embodiment.

First, the EVOH resin (A) having a 1,2-diol structural unit represented by the following general formula (1) used in the present invention will be described.

[In General Formula (1), R1, R2, and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bond chain, and R4, R5, and R6 each independently represent a hydrogen atom. Or an organic group is shown. ]

<EVOH resin (A)>
Such EVOH resin (A) is a water-insoluble resin, and can be obtained by saponifying a copolymer of ethylene and a vinyl ester monomer. Such vinyl ester monomers are typically vinyl acetate. The ethylene-vinyl ester copolymer is produced by any known polymerization method, for example, solution polymerization, suspension polymerization, emulsion polymerization, etc., and the saponification of the ethylene-vinyl ester copolymer can also be performed by a known method.

  The vinyl ester monomer is typically vinyl acetate from the viewpoint of market availability and good impurity treatment efficiency during production. In addition, for example, specifically, aliphatics such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, etc. Examples thereof include aromatic vinyl esters such as vinyl esters and vinyl benzoates, and are usually aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used alone, but a plurality of them may be used simultaneously as necessary.

  In the formula (1), R1 to R6 each independently represent a hydrogen atom or an organic group. Examples of the organic group include saturated hydrocarbon groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and tert-butyl group, and aromatic carbonization such as phenyl group and benzyl group. Examples thereof include a hydrogen group, a halogen atom, a hydroxyl group, an acyloxy group, an alkoxycarbonyl group, a carboxyl group, and a sulfonic acid group. Of these, a saturated hydrocarbon group having 1 to 30 carbon atoms (more preferably 1 to 15 carbon atoms, particularly preferably 1 to 4 carbon atoms) or a hydrogen atom is preferable, and a hydrogen atom is most preferable. In particular, it is preferable that all of R1 to R6 are hydrogen atoms.

In the formula (1), X is a single bond or a bonded chain. From the viewpoint of gas barrier properties of the EVOH resin, a single bond is preferable.
In the case of the above bond chain, for example, hydrocarbon chain such as alkylene, alkenylene, alkynylene, phenylene, naphthylene, etc. (these hydrocarbons may be substituted with halogen such as fluorine, chlorine, bromine, etc.) Structural units containing an ether bond site such as —O—, — (CH ₂ O) m—, — (OCH ₂ ) m—, — (CH ₂ O) nCH ₂ —, etc .; —CO—, —COCO—, —CO A structural unit containing a carbonyl group such as (CH ₂ ) _m CO—, —CO (C ₆ H ₄ ) CO—; a structure containing a sulfur atom such as —S—, —CS—, —SO—, —SO ₂ —, etc. A unit; a structural unit containing a nitrogen atom such as —NR—, —CONR—, —NRCO—, —CSNR—, —NRCS—, —NRNR— or the like; a heteroatom such as a structure containing a phosphorus atom such as —HPO ₄ —; Containing structural unit; -Si (OR _{2 -, - OSi (OR)} 2 -, - OSi (OR) a structural unit containing 2 O- such as silicon _{atoms; -Ti (OR) 2 -,} - OTi (OR) 2 -, - OTi (OR) 2 Examples include structural units containing titanium atoms such as O—; structural units containing metal atoms such as aluminum atoms such as —Al (OR) —, —OAl (OR) —, and —OAl (OR) O—. In these structural units, each R is independently an arbitrary substituent, and is preferably a hydrogen atom or an alkyl group. M is a natural number, and is usually 1-30, preferably 1-15, particularly preferably 1-10. Among these, from the viewpoint of stability during production or use, a hydrocarbon chain having 1 to 10 carbon atoms is preferable, and a hydrocarbon chain having 1 to 6 carbon atoms, particularly a hydrocarbon chain having 1 carbon atom is preferable. .

The most preferable structure in the side chain 1,2-diol structural unit represented by the general formula (1) is a structural unit in which all of R1 to R6 are hydrogen atoms and X is a single bond. That is, the structural unit represented by the following formula (1a) is most preferable.

The content of the side chain 1,2-diol structural unit represented by the general formula (1) in the EVOH resin (A) containing the side chain 1,2-diol structural unit represented by the general formula (1) is as follows: Usually, it is 0.1-30 mol%, Preferably it is 0.5-20 mol%, Most preferably, it is 1-10 mol%.
If the content of the side chain 1,2-diol structural unit is too small, the crystallinity of the EVOH resin (A) layer tends to increase and the stretchability tends to decrease. Cost tends to increase and versatility tends to decrease.
The content of the side chain 1,2-diol structural unit can be calculated from the measurement result of 1H-NMR.

  As for ethylene content in EVOH resin (A), content of the ethylene structural unit measured based on ISO14663 is usually 20-60 mol%, preferably 20-50 mol%, more preferably 28-48 mol%. It is. When the content of the ethylene structural unit is too low, melt molding processability tends to decrease. When the content of the ethylene structural unit is too high, the proportion of OH groups contained in the polymer chain is inevitably lowered, and the gas barrier property tends to be lowered.

  The saponification degree of EVOH resin (A) is a value measured based on JIS K6726 (however, EVOH resin is a solution uniformly dissolved in water / methanol solvent), and is usually 80 to 100 mol%, preferably It is 90-100 mol%, Most preferably, it is 95-100 mol%. If the degree of saponification is too low, gas barrier properties tend to be insufficient.

  The melting point of the EVOH resin (A) having the above structure is usually 100 to 220 ° C., preferably 130 to 200 ° C., particularly preferably 140 to 190 ° C. as measured by a differential scanning calorimeter. is there.

  The melt flow rate (sometimes abbreviated as MFR) of the EVOH resin (A) is usually 1 to 30 g / 10 minutes, preferably 2 to 20 g / 10 minutes, particularly preferably 3 to 15 g at 210 ° C. and a load of 2160 g. / 10 minutes. If the MFR is too small, the inside of the extruder tends to be in a high torque state during molding and the melt moldability tends to decrease. Conversely, if the MFR is too large, the thickness accuracy of the EVOH resin (A) layer obtained tends to decrease. .

  Further, it may contain a monomer that can be copolymerized within a range that does not impair the properties of the EVOH resin (for example, 10 mol% or less with respect to the EVOH resin). For example, specifically, olefins such as propylene, 1-butene and isobutene, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid and (anhydrous) itaconic acid, or Salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, N-alkyl acrylamides having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or salts thereof, acrylamidopropyldimethylamine or Acrylates such as acid salts or quaternary salts thereof, methacrylamide, N-alkylmethacrylamide having 1 to 18 carbon atoms, N, N-dimethylmethacrylamide, 2-methacrylamide propanesulfonic acid or salts thereof, methacrylamidepropyl Zimechi Methacrylamides such as amines or acid salts thereof or quaternary salts thereof, N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide and N-vinylacetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, carbon Number 1 to 18 alkyl vinyl ethers, hydroxyalkyl vinyl ethers, vinyl ethers such as alkoxyalkyl vinyl ethers, vinyl chloride, vinylidene chloride, vinyl halides such as vinyl fluoride, vinylidene fluoride, vinyl bromide, trimethoxyvinyl silane, etc. Allyl halide compounds such as vinylsilanes, allyl acetate and allyl chloride, allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl) -a Examples include ammonium chloride and acrylamido-2-methylpropanesulfonic acid. These monomers may be used alone or in combination of two or more.

  The EVOH resin (A) as described above has a lower melting point than that of a normal EVOH resin having no side chain 1,2-diol structural unit, is excellent in stretchability, and can be subjected to a stretching process at a high magnification. it can. Such a polymer usually has a total content of vinyl alcohol structural units and side chain 1,2-diol structural units of 40 to 80 mol%.

  The method for obtaining the EVOH resin (A) used in the present invention is as follows. When the EVOH resin containing the structural unit (1a) which is the most preferable structure is taken as an example, [1] As a comonomer capable of supplying a side chain 1,2-diol unit 3,4-diol-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-ol-1-butene, 4-acyloxy-3-ol-1-butene, 3,4-diacyloxy- A method of using 2-methyl-1-butene or the like to copolymerize with vinyl ester monomer and ethylene to obtain a copolymer, and then saponifying the copolymer; [2] supplying side chain 1,2-diol units Vinyl ethylene carbonate or the like is used as a comonomer that can be copolymerized with a vinyl ester monomer and ethylene to obtain a copolymer, which is then saponified and decarboxylated. Method: [3] Using 2,2-dialkyl-4-vinyl-1,3-dioxolane or the like as a comonomer capable of supplying a side chain 1,2-diol unit, copolymerizing these with a vinyl ester monomer and ethylene It can be produced by a method of obtaining a copolymer and then saponifying and deacetalizing.

  Of the above production methods, the method [1] is preferably employed, and more preferably, 3,4-diasiloxy-1-butene is copolymerized with a vinyl ester monomer and ethylene in terms of excellent copolymerization reactivity. This is a method for saponifying the obtained copolymer. More preferably, 3,4-diacetoxy-1-butene is used as 3,4-diasiloxy-1-butene. According to such a production method, the polymerization proceeds favorably, and side chain 1,2-diol units are easily introduced uniformly into the main chain of the EVOH resin. As a result, unreacted monomers are reduced, and the EVOH resin (A) There is an advantage that impurities contained in the layer can be reduced.

Specifically, the reactivity ratio of each monomer when vinyl acetate and 3,4-diacetoxy-1-butene are copolymerized is r (vinyl acetate) = 0.710, r (3,4-diacetoxy -1-butene) = 0.701. This is compared with the reactivity ratio of each monomer when using vinyl ethylene carbonate of [2], r (vinyl acetate) = 0.85, r (vinyl ethylene carbonate) = 5.4, 3,4-diacetoxy. It can be seen that -1-butene is more excellent in copolymerization reactivity with vinyl acetate.
The chain transfer constant of 3,4-diacetoxy-1-butene is Cx (3,4-diacetoxy-1-butene) = 0.003 (65 ° C.). Cx (vinyl ethylene carbonate) = 0.005 (65 ° C.) of vinyl ethylene carbonate used in the method [2] and 2,2-dimethyl-4-vinyl-1,3-dioxolane used in the method [3] Compared with Cx (2,2-dimethyl-4-vinyl-1,3-dioxolane) = 0.023 (65 ° C), the chain transfer constant of 3,4-diacetoxy-1-butene is small, and the degree of polymerization is increased. It turns out that it becomes difficult to become a cause of a polymerization rate fall.

  Furthermore, when 3,4-diacetoxy-1-butene is used, the by-product produced when the resulting copolymer is saponified is the same as the by-product derived from the vinyl acetate structural unit. Therefore, the method [1] using 3,4-diacetoxy-1-butene also has an industrial advantage that it is not necessary to provide a special apparatus or process for the post-treatment.

  On the other hand, the EVOH resin having a side chain 1,2-diol unit produced by the production method [2] has a carbonate ring remaining in the side chain when the degree of saponification is low or when decarboxylation is insufficient. The carbonic acid tends to be decarboxylated during melt molding and cause the resin to foam. In addition, the EVOH resin having a side chain 1,2-diol unit produced by [3] also melts the monomer-derived functional group (acetal ring) remaining in the side chain, as in the production method [2]. Since there is a tendency that odors are generated by desorption during molding, it is necessary to use this in mind.

  In addition, 3,4-diol-1-butene used as a raw material in the method [1] is from Eastman Chemical Co., and 3,4-diacetoxy-1-butene is from Eastman Chemical Co. for industrial production, and at reagent level. Acros products can be obtained from the market. 3,4-diacetoxy-1-butene obtained as a by-product during the production process of 1,4-butanediol can also be used. 3,4-diacetoxy-1-butene used as a raw material includes 3,4-diacetoxy-1-butane, 1,4-diacetoxy-1-butene, 1,4-diacetoxy-1-butane, etc. as a small amount of impurities. May be included.

The side chain 1,2-diol structural unit-containing EVOH resin (A) used in the EVOH resin (A) layer is not only one type, but also has different saponification degrees, different molecular weights, and other copolymer monomers. Two or more kinds of side chain 1,2-diol structural unit-containing EVOH resins (A) such as those of different types and those of different ethylene structural unit contents may be used in combination.
When those having different ethylene structural unit contents are used in combination, the other structural units may be the same or different, but the ethylene content difference is usually 1 mol% or more, preferably 2 mol% or more. Particularly preferred is 2 to 20 mol%. If the ethylene content difference is too large, the stretchability may be poor.

In some cases, an unmodified EVOH resin not containing a side chain 1,2-diol structural unit may be mixed. In the case of an EVOH resin mixture, the content of the side chain 1,2-diol structural unit is usually 0.5 to 30 mol%, preferably 1 to 20 mol%, as an average value of the entire EVOH resin mixture. In particular, it is preferable to mix at a ratio of 1 to 10 mol%.
In the present invention, it is preferable that the EVOH resin containing no side chain 1,2-diol unit is not mixed in the side chain 1,2-diol structural unit-containing EVOH resin (A) layer. When viewed from a finer viewpoint, the side chain 1,2-diol-containing EVOH resin and the unmodified EVOH resin have different stretch characteristics, so the excellent stretchability of the side chain 1,2-diol-containing EVOH resin is sufficient. It is because it may not appear in.

  When blending and using two or more different types of EVOH resins (A) containing 1,2-diol structural units of side chains, the method for producing the blend is not particularly limited. For example, a method in which each paste of vinyl ester copolymer before saponification is mixed and then saponified; a method in which EVOH resin after saponification is dissolved in alcohol or a mixed solvent of water and alcohol; and a method in which each EVOH resin is mixed A method of melt-kneading after mixing the pellets or powder of the above; a method of mechanically mixing the pellets or powder of each EVOH resin (dry blending), and the like.

  The EVOH resin (A) layer may be composed of a side-chain 1,2-diol structural unit-containing EVOH resin having the above-described configuration, or a range that does not impair the effects of the present invention (for example, with respect to the EVOH resin). If it is less than 30% by weight, it may contain other polymers than EVOH resin, and various additives such as various additives.

  Examples of additives include saturated aliphatic amides (such as stearic acid amide), unsaturated fatty acid amides (such as oleic acid amide), bis fatty acid amides (such as ethylene bisstearic acid amide), and low molecular weight polyolefins (such as molecular weight). Plasticizers such as aliphatic polyhydric alcohols such as lubricants such as low molecular weight polyethylene (low molecular weight polyethylene of about 500 to 10,000, low molecular weight polypropylene, etc.), insoluble inorganic salts (such as hydrotalcite), ethylene glycol, glycerin, hexanediol, etc. , Light stabilizers, heat stabilizers, antioxidants, UV absorbers, colorants, desiccants, antistatic agents, surfactants, antibacterial agents, antiblocking agents, fillers (eg inorganic fillers), oxygen absorbers Etc.

  Furthermore, in order to improve various physical properties such as heat stability at the time of melt molding, organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, behenic acid or alkali metal salts thereof (sodium, Potassium), alkaline earth metal salts (calcium, magnesium, etc.), zinc salts, inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, boric acid, or their alkali metal salts (sodium) , Potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), and salts such as zinc salts may be added. Of these, it is particularly preferable to add boron compounds, acetates and phosphates including acetic acid, boric acid and salts thereof.

  When acetic acid is added, the amount added is usually 0.001 to 1 part by weight, preferably 0.005 to 0.2 part by weight, particularly preferably 0.010 to 100 parts by weight of EVOH resin (A). 0.1 parts by weight. If the amount of acetic acid added is too small, the effect of containing acetic acid tends to be insufficient, and conversely if too large, it tends to be difficult to obtain a uniform EVOH layer thickness.

  Moreover, when adding a boron compound, the addition amount is 0.001-1 weight part normally by boron conversion (after ashing and analyzing by ICP emission spectrometry) with respect to 100 weight part of EVOH resin (A). Yes, preferably 0.002 to 0.2 parts by weight, particularly preferably 0.005 to 0.1 parts by weight. If the addition amount of the boron compound is too small, the effect of adding the boron compound may not be sufficiently obtained. Conversely, if the addition amount is too large, it may be difficult to obtain a uniform EVOH layer thickness.

  Moreover, when adding a phosphoric acid compound, the addition amount is 0.001-1 weight part normally in conversion of a phosphate group with respect to 100 weight part of EVOH resin (A), Preferably it is 0.002-0.2. Parts by weight, particularly preferably 0.005 to 0.1 parts by weight. If the addition amount of the phosphoric acid compound is too small, the effect of adding the phosphoric acid compound may not be sufficiently obtained. Conversely, if the addition amount is too large, it tends to be difficult to obtain a uniform EVOH layer thickness.

  In addition, the amount of acetate and phosphate (including hydrogen phosphate) added is usually in metal conversion (after ashing and analyzed by ICP emission spectrometry) with respect to 100 parts by weight of EVOH resin (A). 0.0005 to 0.1 part by weight, preferably 0.001 to 0.05 part by weight, particularly preferably 0.002 to 0.03 part by weight. On the contrary, if the amount is too large, it tends to be difficult to obtain a uniform EVOH layer thickness. In addition, when adding 2 or more types of salts to EVOH resin (A), it is preferable that the sum total exists in the range of said addition amount.

  Furthermore, unavoidably contained monomer residues for the production of EVOH resin (A), saponified monomers, and so-called impurities may be contained. Specific examples of inevitable impurities include 3,4-diacetoxy-1-butene, 3,4-diol-1-butene, 3,4-diacetoxy-1-butene, and 3-acetoxy-4-ol-1. -Butene, 4-acetoxy-3-ol-1-butene and the like.

  The method of adding the boron compound, acetate, and phosphate to the EVOH resin (A) is not particularly limited. I) EVOH resin (A) containing a side chain 1,2-diol having a water content of 20 to 80% by weight The porous precipitate is brought into contact with an aqueous solution of the additive to contain the additive and then dried; ii) a homogeneous solution of the side chain 1,2-diol-containing EVOH resin (A) (water / alcohol solution) And the like, and then extruding into a coagulating solution in the form of a strand, then cutting the resulting strand into pellets and further drying treatment; iii) EVOH containing side chain 1,2-diol A method in which the resin (A) and the additive are mixed together and then melt-kneaded with an extruder or the like; iv) In the production of the EVOH resin (A) containing a side chain 1,2-diol, it was used in the saponification step. Alkali (water Sodium, potassium hydroxide, etc.) is neutralized with an organic acid such as acetic acid, the amount of organic acids and by-product salts such as acetic acid remaining can be mentioned a method in which or adjusted by water washing treatment. In order to obtain the effects of the present invention more remarkably, the method i) and ii), which are excellent in the dispersibility of the additive, and the method iv) are preferred when an organic acid and a salt thereof are contained.

The EVOH resin (A) layer used in the present invention can be prepared by blending the EVOH resin as described above, other polymers added as necessary, additives and the like, and melt-kneading. The side chain 1,2-diol-containing EVOH resin (A) in the EVOH resin (A) layer is maintained so that the EVOH resin (A) layer retains the characteristics of the side chain 1,2-diol-containing EVOH resin (A). ) Content is preferably 70% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more.
Therefore, these compounding agents are usually less than 30% by weight, preferably less than 20% by weight, and particularly preferably less than 10% by weight.

<Polyolefin resin (B> having an amide compound represented by the general formula (2))
In the present invention, the polyolefin resin layer is a polyolefin resin (B) layer containing an amide compound represented by the following general formula (2).

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ]

First, the polyolefin resin will be described.
Examples of the polyolefin resin used in the present invention usually include polyolefin resins having 2 to 5 carbon atoms in the monomer, such as polyethylene resins, polypropylene resins, polybutene resins, and polypentene resins.

  Specific examples of the polyethylene resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), Ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-propylene (block or random) copolymer, ethylene-acrylic acid copolymer (EAA), ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer Examples thereof include a polymer (EMAA) and an ethylene-methacrylate copolymer.

Specific examples of the polypropylene resin include polypropylene (PP), propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, and the like. The constitutional unit derived from propylene of the polypropylene resin is usually 90 to 100 mol%, preferably 90 to 97 mol%. Moreover, when it contains the structural unit obtained from a C4-C20 alpha olefin, it is 0.1-10 mol% normally, More preferably, it is 1.0-5 mol%. If there is too much such comonomer, the rigidity tends to decrease. If the structural unit obtained from the comonomer is within the above range, a plurality of α-olefins may be used.
Specific examples of the comonomer copolymerized with propylene and / or the α-olefin having 4 to 20 carbon atoms include butene-1, pentene-1, hexene-1, octene-1, and 4-methylpentene-1. Etc.

  Examples of the polybutene resin include polybutene, butene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, and the like. Examples of the polypentene resin include homopolymers or copolymers of olefins such as polypentene and polymethylpentene.

Depending on the case, those obtained by graft-modifying these polyolefin-based resins alone or a copolymer with an unsaturated carboxylic acid or an ester thereof can be used.
When such a polyolefin resin is a copolymer, the olefin monomer is usually 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol%. The copolymer may be a random copolymer or a block copolymer. If these resins have stereoregularity, they may be isotactic or syndiotactic.

  Of these, polyethylene resins and polypropylene resins are preferable, and polypropylene resins are particularly preferable in terms of excellent transparency and heat resistance.

The density of the polyolefin resin used in the present invention is a value measured in accordance with JIS K7112, and is usually 0.5 to 3.0 g / cm ³ , preferably 0.5 to 2.0 g / cm ³ , particularly preferably. 0.8 to 1.5 g / cm ³ . If the density is too large, the stretchability tends to decrease, and if it is too small, the heat resistance and rigidity tend to be insufficient.

  The melt flow rate (MFR) of the polyolefin resin used in the present invention is a value measured in accordance with JIS K7210 (230 ° C., 2160 g load), and is usually 0.1 to 100 g / 10 minutes, preferably 0.8. It is 5 to 50 g / 10 minutes, and more preferably 1 to 15 g / 10 minutes.

The production method of the polyolefin resin used in the present invention is not particularly limited as long as it has the above-mentioned characteristics. For example, as a catalyst applied for producing the polyolefin resin, a Ziegler-Natta type catalyst, three Examples thereof include a titanium chloride catalyst, a magnesium chloride-supported titanium tetrachloride catalyst, and a metallocene catalyst. Among them, a metallocene catalyst having favorable adhesiveness, transparency, odor, and the like is preferable.
As a polypropylene-type resin manufactured with the metallocene catalyst marketed, the brand name Wintec by Nippon Polypro Co., Ltd. etc. are mentioned, for example.

Furthermore, in the present invention, it is also possible to use a blend of two or more polyolefin resins having different resin types and physical property values (density, MFR, molecular weight distribution, etc.).

The polyolefin resin of the present invention contains an amide compound represented by the following general formula (2).

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ]

  Specific examples of the amide compound represented by the general formula (2) include 1,2,3-propanetricarboxylic acid tricyclohexylamide; 1,2,3-propanetricarboxylic acid tri (2-methylcyclohexylamide), 1, 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide) such as 2,3-propanetricarboxylic acid tri (3-methylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-methylcyclohexylamide) 1,2,3-propanetricarboxylic acid tri (2-ethylcyclohexylamide) 1,2,3-propanetricarboxylic acid tri (3-ethylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-ethyl); Cyclohexylamide) and the like 1,2,3-propanetricarboxylic acid tri 1,2,3-propanetricarboxylic acid tri (2-n-propylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3-n-propylcyclohexylamide), 1,2,3 Propanetricarboxylic acid tri (4-n-propylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (2-iso-propylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3-iso- 1,2,3-propanetricarboxylic acid tri (propylcyclohexylamide), such as 1,2,3-propanetricarboxylic acid tri (4-iso-propylcyclohexylamide); Tri (2-n-butylcyclohexyl) acid Amide), 1,2,3-propanetricarboxylic acid tri (3-n-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-n-butylcyclohexylamide), 1,2,3-propane Tricarboxylic acid tri (2-iso-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3-iso-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-iso-butylcyclohexyl) Amide), 1,2,3-propanetricarboxylic acid tri (2-sec-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3-sec-butylcyclohexylamide), 1,2,3-propane Tricarboxylic acid tri (4-sec-butylcyclohexylamide), 1,2 , 3-propanetricarboxylic acid tri (2-tert-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3-tert-butylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4- 1,2,3-propanetricarboxylic acid tri (butylcyclohexylamide) such as tert-butylcyclohexylamide); 1,2,3-propanetricarboxylic acid tri (4-n-pentylcyclohexylamide), 1,2,3- Propanetricarboxylic acid tri (4-n-hexylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-n-heptylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-n-octyl) Cyclohexylamide), 1,2,3-propanetrical Acid tri [4- (2-ethylhexyl) cyclohexylamide], 1,2,3-propanetricarboxylic acid tri (4-n-nonylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-n- Decylcyclohexylamide), 1,2,3-propanetricarboxylic acid [(cyclohexylamide) di (2-methylcyclohexylamide)], 1,2,3-propanetricarboxylic acid [di (cyclohexylamide) (2-methylcyclohexylamide) )],

1,2,3,4-butanetetracarboxylic acid tetracyclohexylamide, 1,2,3,4-butanetetracarboxylic acid tetra (2-methylcyclohexyl) amide, 1,2,3,4-butanetetracarboxylic acid tetra 1,3-3,4-butanetetracarboxylic acid tetra (methylcyclohexylamide) such as (3-methylcyclohexyl) amide, 1,2,3,4-butanetetracarboxylic acid tetra (4-methylcyclohexylamide); 1 , 2,3,4-Butanetetracarboxylic acid tetra (2-ethylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (3-ethylcyclohexylamide), 1,2,3,4-butane 1,2,3,4-butanetetracarboxylic acid such as tetracarboxylic acid tetra (4-ethylcyclohexylamide) La (ethylcyclohexylamide); 1,2,3,4-butanetetracarboxylic acid tetra (2-n-propylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (3-n-propylcyclohexyl) Amide), 1,2,3,4-butanetetracarboxylic acid tetra (4-n-propylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (2-iso-propylcyclohexylamide), 1 1,2,3,4-butanetetracarboxylic acid tetra (3-iso-propylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-iso-propylcyclohexylamide) 3,4-butanetetracarboxylic acid tetra (propylcyclohexylamide); 1,2,3,4-butane Tetracarboxylic acid tetra (2-n-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (3-n-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-n-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (2-iso-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (3-iso) -Butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-iso-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (2-sec-butylcyclohexylamide) ), 1,2,3,4-butanetetracarboxylic acid tetra (3-sec-butylcyclohexylamino) 1), 1,2,3,4-butanetetracarboxylic acid tetra (4-sec-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (2-tert-butylcyclohexylamide), 1 1,2,3,4-butanetetracarboxylic acid tetra (3-tert-butylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-tert-butylcyclohexylamide), 3,4-butanetetracarboxylic acid tetra (butylcyclohexylamide); 1,2,3,4-butanetetracarboxylic acid tetra (4-n-pentylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid Tetra (4-n-hexylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4- -Heptylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-n-octylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra [4- (2-ethylhexyl) Cyclohexylamide], 1,2,3,4-butanetetracarboxylic acid tetra (4-n-nonylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (4-n-decylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid [di (cyclohexylamide) di (2-methylcyclohexylamide)] and the like.

Among the amide compounds, particularly from the viewpoint of balance of appearance and rigidity and easy availability of raw materials, an amide system in which R7 in α in the general formula (2) is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. A compound is preferable, and in particular, an amide compound in which R7 in α of the above general formula (2) is a hydrogen atom or a methyl group is particularly preferable.
Moreover, the amide compound whose n in General formula (2) is 1 is especially preferable.
Furthermore, it is preferable that the functional groups α in the general formula (2) are the same.
More specifically, 1,2,3-propanetricarboxylic acid tricyclohexylamide, 1,2,3-propanetricarboxylic acid tri (2-methylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (3- Methylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-methylcyclohexylamide) and the like.
Said amide compound can be used individually or in combination of 2 or more types as appropriate.

  The crystal form of the amide compound is not particularly limited as long as the effect of the present invention can be obtained, and any crystal form such as hexagonal crystal, monoclinic crystal, cubic crystal and the like can be used. These crystals are also known or can be produced according to known methods.

  The amide compound preferably has a purity of substantially 100%, but may contain some impurities. Even when impurities are contained, the purity of the amide compound is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly 97% by weight or more. Examples of the impurities include monoamide dicarboxylic acid derived from a reaction intermediate or unreacted substance or an ester compound thereof, diamide monocarboxylic acid or an ester compound thereof, an imide compound derived from a side reaction product, and the like.

  A well-known method can be employ | adopted for the manufacturing method of the amide compound which concerns on this invention. For example, it can be produced from a specific aliphatic polycarboxylic acid component and a specific alicyclic monoamine component according to a conventionally known method (for example, JP-A-7-242610).

  Examples of the aliphatic polycarboxylic acid component include 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, acid chlorides and anhydrides of the polycarboxylic acid, and the polycarboxylic acid. Examples thereof include derivatives such as esters with lower alcohols having 1 to 4 carbon atoms. These aliphatic polycarboxylic acid components can be used for amidation alone or in combination of two kinds.

The alicyclic monoamine component is usually at least one selected from the group consisting of cyclohexylamine and cyclohexylamine substituted with a hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, alone or Two or more kinds can be mixed and subjected to amidation.
Specifically, cyclohexylamine, 2-methylcyclohexylamine, 3-methylcyclohexylamine, 4-methylcyclohexylamine methylcyclohexylamine, 2-ethylcyclohexylamine, 2-n-propylcyclohexylamine, 2-iso-propylcyclohexyl Examples include amines, 2-n-butylcyclohexylamine, 2-iso-butylcyclohexylamine, 2-sec-butylcyclohexylamine, 2-tert-butylcyclohexylamine and the like.

  The cyclohexylamine substituted with the above alkyl group may be any of a cis isomer, a trans isomer and a mixture of these stereoisomers. The preferred cis: trans ratio is preferably in the range of 50:50 to 0: 100, particularly preferably in the range of 35:65 to 0: 100.

  The particle size of the amide compound according to the present invention is not particularly limited as long as the effects of the present invention can be obtained, but those having a particle size as small as possible are preferable from the viewpoint of the dissolution rate (or dissolution time) for the molten polyolefin resin. . When the measurement value of the particle size obtained by the laser diffraction light scattering method is adopted, the maximum particle size of the amide compound is 200 μm or less, preferably 100 μm or less, more preferably 50 μm, particularly 10 μm or less. Is done.

  As a method for adjusting the maximum particle size within the above range, a method using a known pulverizer in this field is generally used, and a known classifier can be used if necessary. Specifically, a fluidized bed type counter jet mill 100AFG (trade name, manufactured by Hosokawa Micron Corporation), a supersonic jet mill PJM-200 (trade name, manufactured by Nippon Pneumatic Co., Ltd.), a pin mill, etc. And dry classifiers (such as cyclones and micron separators).

In the polyolefin resin (B) layer containing the amide compound represented by the general formula (2), the content of the amide compound represented by the general formula (2) relative to the polyolefin resin is usually 0.001 to 0.001. 5% by weight, preferably 0.01 to 1% by weight, particularly preferably 0.05 to 0.5% by weight.
When the content is too large, the heat resistance and rigidity tend to decrease, and when the content is too small, the stretchability tends to decrease.

  The polyolefin resin may contain a known compounding agent as long as the effects of the present invention are not significantly impaired. As such compounding agents, stabilizers (metal compounds, epoxy compounds, nitrogen compounds, phosphorus compounds, sulfur compounds, etc.) used as compounding agents for ordinary polyolefin resins, ultraviolet absorbers (benzophenone compounds, benzotetraazole compounds) Compounds), antioxidants (phenolic compounds, phosphite compounds, sulfur compounds, etc.), surfactants, lubricants (aliphatic hydrocarbons such as paraffin and wax, higher fatty acids having 8 to 22 carbon atoms) Higher fatty acid metal salt having 8 to 22 carbon atoms (for example, Al, Ca, Mg, Zn salt), higher aliphatic alcohol having 8 to 22 carbon atoms, polyglycol, higher fatty acid having 4 to 22 carbon atoms and carbon number Ester with 4-18 aliphatic monohydric alcohol, higher fatty acid amide having 8 to 22 carbon atoms, silicone oil, rosin derivative, etc.) Agents, foaming aids, polymer additives, plasticizers (dialkyl phthalates, dialkyl hexahydrophthalates, etc.), crosslinking agents, crosslinking accelerators, antistatic agents, dispersants, organic pigments, processing aids, other cores Various additives such as an agent are exemplified. The amount added can be appropriately selected within a range not impairing the effects of the present invention.

  For example, when the above metal compound or higher fatty acid metal salt (for example, calcium stearate) is blended in the polyolefin resin composition of the present invention, the polyolefin resin molded product of the present invention (especially when the polyolefin resin is a polypropylene random copolymer). There is a tendency for the transparency of to improve more. The amount of the additive used is preferably 0.001 to 0.2 parts by weight, and more preferably 0.005 to 0.1 parts by weight with respect to 100 parts by weight of the polyolefin resin.

<Mixing method>
The polyolefin resin (B) containing the amide compound represented by the general formula (2) used in the present invention is composed of the amide compound component represented by the general formula (2) and other additives (for example, as necessary) And other modifiers for polyolefin resins) can be obtained by blending them with polyolefin resins.

As a manufacturing method of polyolefin resin (B) containing the amide compound represented by the general formula (2) used in the present invention, for example,
(I) polyolefin resin (powder, granules, flakes, pellets, etc.), the amide compound component represented by the above general formula (2), and if necessary, the compounding agent is charged to a desired composition ratio, and then A dry blend type polyolefin resin (B) by dry blending using a known mixer (eg, Henschel mixer, ribbon blender, V blender, etc.),
(Ii) The above-mentioned dry blend type polyolefin resin composition is usually 160 to 300 ° C., preferably 180 to 280 ° C., particularly preferably, using a known kneader (for example, a uniaxial or biaxial extruder). Is melt-kneaded at a temperature of 200 ° C. to 260 ° C., the extruded strand is cooled, and the obtained strand is cut, extruded into water for cutting (under water cut method), or extruded and immediately cut (hot A method of obtaining a pellet-type polyolefin resin (B) by a cutting method), a method of blending an amide compound represented by the above general formula (2) with a molten polyolefin resin,
Etc. are exemplified.
Among these, the method (ii) is preferable because the dispersibility of the amide compound is excellent.

  In the pellet type method, the polyolefin resin composition of high-concentration master batch pellets in which the amide compound component represented by the general formula (2) is usually 1 to 20% by weight, preferably 2 to 15% by weight, is used. A method of obtaining is also included. The polyolefin resin composition of the high-concentration master batch pellet is preferably subjected to a molding step after being appropriately diluted with a polyolefin resin so as to have a desired composition ratio.

  In order to obtain the effect of the present invention more effectively, in the melt-kneading step described in (ii) above, the step substantially includes converting the amide compound component represented by the general formula (2) into a molten polyolefin resin. It is preferable to provide a step of complete dissolution. In particular, this is an important process when the polyolefin resin composition of the present invention is used for applications in which the transparency of the polyolefin resin molding is important.

<Molding method>
The multilayer structure of the present invention comprises a polyolefin resin (B) containing an amide compound represented by the general formula (2) on at least one surface of the EVOH resin (A) layer. It can be manufactured according to the method. For example, specifically, a method of melt extrusion laminating the polyolefin resin (B) containing the amide compound represented by the general formula (2) on the sheet of the EVOH resin (A), conversely, the polyolefin resin (B ) A melt extrusion method such as a method of melt extrusion laminating EVOH resin (A), a method of coextrusion molding of both resins (A) and (B), a method of co-injection molding, and the like. A method of dry laminating a base material (layer) with a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, a polyurethane compound, or the like, and after applying the resin solution on another base material Examples include a method for removing the solvent.
Among these, the melt molding method is preferable from the viewpoint of cost and environment, and the co-extrusion molding method and the co-injection molding method are particularly preferable.

Next, the obtained multilayer structure is stretched to obtain a stretched multilayer structure. In this stretching step, it is preferable to perform a heat stretching process.
Here, the heat stretch molding means an operation in which the multilayer structure is uniformly heated with various heaters, heat sources, and the like, and molded into various shapes by a chuck, a plug, a vacuum force, a pneumatic force, and the like.
The heat stretching may be either uniaxial stretching or biaxial stretching. The heat stretching method includes a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blow method, a deep drawing method, and a vacuum forming method. A pressure forming method, a vacuum pressure forming method, or the like can be employed. In the case of biaxial stretching, both a simultaneous biaxial stretching method and a sequential biaxial stretching method can be employed. The temperature of the multilayer structure at the time of heat stretching is selected from the range of about 80 to 170 ° C, preferably about 100 to 160 ° C.

Especially, in this invention, the effect of this invention is expressed more effectively by performing co-injection stretch blow molding.
The co-injection stretch blow molding is a multilayer having a polyolefin resin (B) layer containing an amide compound represented by the general formula (2) on at least one surface of the EVOH resin (A) layer by a co-injection molding method. A preformed body (preform) that is a structure is manufactured, and the preform is stretch blow molded to obtain a multilayer hollow container that is a stretched multilayer structure.
Examples of such multilayer hollow containers include multilayer bottles and multilayer cups, with multilayer bottles being preferred.

  Such a preform (preform) means a hollow tubular molded body before air is blown in stretch blow molding. For example, specifically, it is a bottomed molded article having a trunk and a mouth, and typically a test tube type. The thickness of the body part of such a preform is usually 1 to 5 mm.

In order to produce the preform, usually, an injection molding machine having two injection cylinders and a multi-layer manifold system is used, and the molten EVOH resin (A) and the polyolefin system are contained in a single mold. The resin (B) is obtained by injecting the resin (B) from the respective injection cylinders simultaneously or at different times through the multilayer manifold system.
For example, when obtaining a preform with a three-layer structure of polyolefin resin (B) layer / EVOH resin (A) layer / polyolefin resin (B) layer, the polyolefin resin (B) as the outer layer is injected first. Then, a predetermined amount of EVOH resin (A) as an intermediate layer is injected, and further injection of the polyolefin resin (B) is continued, so that the intermediate EVOH resin (A) layer is on both sides of the polyolefin resin (B) layer. Thus, a preform that is completely encapsulated is obtained.

As injection molding conditions for such a preform, the injection molding temperature of EVOH resin (A) is usually 150 to 300 ° C., preferably 160 to 270 ° C., particularly preferably 170 to 230 ° C., and such temperature is too low. The melting of the EVOH resin (A) may be insufficient, and if it is too high, the thermal appearance of the EVOH resin (A) tends to deteriorate the appearance of the multilayer hollow container obtained later or generate odor. is there.
On the other hand, the injection molding temperature of the polyolefin resin (B) is usually 150 to 300 ° C., preferably 160 to 270 ° C., particularly 170 to 250 ° C. If the temperature is too low, the polyolefin resin (B) is melted. If it is too high, the appearance of the multilayer hollow container obtained later may be deteriorated or odor may be generated due to thermal decomposition of the polyolefin resin (B).

Furthermore, the temperature of the multi-layer manifold part where the EVOH resin (A) and the polyolefin resin (B) join is usually 150 to 300 ° C., preferably 160 to 270 ° C., particularly preferably 170 to 250 ° C. Is too low, the polyolefin resin (B) may be insufficiently melted. If it is too high, the thermal decomposition of the EVOH resin (A) and the polyolefin resin (II) may cause the multilayer hollow container to be obtained later. Appearance may deteriorate or odor may occur.
The temperature of the mold into which the EVOH resin (A) and the polyolefin resin (B) flow is usually 0 to 80 ° C., preferably 5 to 60 ° C., particularly 10 to 30 ° C., and the temperature is too low. The mold may condense, and the appearance of the resulting preform tends to be reduced. If it is too high, the blow-stretchability of the preform may be reduced, or the multilayer hollow container obtained later There exists a tendency for transparency and transparency to fall.

  Thus, a preform having a multilayer structure can be obtained. The injection-molded preform is stored and / or transported at room temperature for a certain time, and then sent to a reheating process to be blow-drawn. Next, the preform is heated, stretched mechanically in the longitudinal direction while maintaining a constant temperature in the blow mold, and stretched by blowing in pressurized air simultaneously or sequentially to expand in the circumferential direction. A multilayer hollow container having an arbitrary shape can be obtained.

  Reheating the preform can be performed using a heating element such as an infrared heater or a block heater. The temperature of the heated parison is usually 50 to 180 ° C, preferably 85 to 170 ° C, particularly preferably 90 to 160 ° C. If this temperature is too low, the shape and thickness of the resulting multi-layer hollow container may be inhomogeneous, and if it is too high, the extensibility will be too high and the uniformity of the extension will be too high. There is a tendency that the shape and thickness of the resulting multilayer hollow container are not uniform.

  As described above, the reheated preform is biaxially stretched to obtain a multi-layer hollow container. Generally, the preform is stretched mechanically by a plug, a rod, etc. about 1 to 7 times in the longitudinal direction. Then, it is stretched about 1 to 7 times in the lateral direction by pneumatic force, and the target multilayer hollow container is obtained. Such longitudinal stretching and lateral stretching can be performed simultaneously or sequentially. It is also possible to use aerodynamic force in the longitudinal stretching.

The multilayer structure of the present invention, the multilayer stretched structure, and the multilayer hollow container are composed of the EVOH resin (A) layer a (a1, a2,...) And the polyolefin resin (B) layer b (b1). , B2,..., A / b, b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b2 Arbitrary combinations such as / b1 / a / b1 / a / b1 / b2 are possible. In addition, when R represents a recycling layer containing a mixture of the EVOH resin and the thermoplastic resin, which is obtained by remelt molding an end portion or a defective product generated in the process of manufacturing the multilayer structure, b / R / A, b / R / a / b, b / R / a / R / b, b / a / R / a / b, b / R / a / R / a / R / b, etc. It is. Among these, the EVOH resin (A) layer is preferably an intermediate layer.
In particular, when a multilayer structure is manufactured by a co-injection molding method or when co-injection stretch blow molding is performed, it is advantageous that an end portion or a defective product generated in the process of manufacturing the multilayer structure does not occur.

  In addition, an adhesive resin layer can be provided between the EVOH resin (A) and the polyolefin resin (B) as necessary, and a known one may be used as the adhesive resin. . Such an adhesive resin varies depending on the type of resin b, and may be appropriately selected. Typically, however, an unsaturated carboxylic acid or its anhydride is chemically bonded to a polyolefin resin by an addition reaction or a graft reaction. And a modified olefin polymer containing a carboxyl group obtained in this manner. For example, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block and random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft A modified ethylene-vinyl acetate copolymer or the like, and one or a mixture of two or more selected from these is preferable. These adhesive resins can be blended with EVOH compositions, other EVOH, polyisobutylene, rubber / elastomer components such as ethylene-propylene rubber, and b-layer resins. Moreover, in order to prevent delamination of the EVOH resin (A) and the polyolefin resin (B), these adhesive resins are blended in the polyolefin resin (B) layer and bonded to the polyolefin resin (B) layer itself. It is also preferable to impart properties. The amount of such adhesive resin is usually less than 30% by weight based on the polyolefin resin.

  The multilayer structure, stretched multilayer structure, and multilayer hollow container of the present invention may contain a thermoplastic resin (C) layer other than the EVOH resin (A) and the polyolefin resin (B). Specific examples of such thermoplastic resins include known general thermoplastic resins such as polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as 6 nylon and 66 nylon. And also when providing a thermoplastic resin (C) layer, it is possible to provide the said adhesive resin layer.

The thickness of the obtained multilayer structure, stretched multilayer structure, and EVOH resin (A) layer of the multilayer hollow container varies depending on the required gas barrier properties, but is usually 1-1000 μm, preferably 3-500 μm, Particularly preferably, the thickness is 5 to 100 μm. If the thickness is too thin, sufficient gas barrier properties tend not to be obtained. Conversely, if the thickness is too thick, stretchability tends to be insufficient.
The thickness of the polyolefin-based resin (B) layer cannot be generally stated depending on the layer configuration, the type of polyolefin-based resin (B), the type of adhesive resin, the use and packaging form, the required physical properties, etc., but usually 10 to 1000 μm The thickness is preferably 20 to 5000 μm, particularly preferably 30 to 1000 μm. If the thickness is too thin, the heat resistance and rigidity of the bottle tend to be reduced. Conversely, if the thickness is too thick, the stretchability tends to be reduced.
When it has an adhesive resin layer, its thickness cannot be generally stated depending on the layer structure, the type of thermoplastic resin, the type of adhesive resin, the use and packaging form, the required physical properties, etc., but usually 1 to 500 μm, preferably Is selected from the range of about 3 to 250 μm, particularly preferably about 5 to 50 μm. If the thickness is too thin, sufficient adhesion tends not to be obtained, and if it is too thick, it tends to be economically disadvantageous.

The thickness structure of the EVOH resin (A) layer and the polyolefin resin (B) layer is such that the polyolefin resin (B) layer is thicker when all the same resin layers in the multilayer structure are added together. B) As the thickness ratio of the layer / EVOH resin layer, the ratio of the thickest layers is usually 1 to 100, preferably 10 to 50.
In addition, the thickness structure of the EVOH resin layer and the adhesive resin layer is usually 0.1 to 100, preferably 0. The thickness ratio of the EVOH resin layer / adhesive resin layer is the thickest layer. 5-20.

In particular, the thickness of each layer in the stretched multilayer structure and the multilayer hollow container cannot be said unconditionally depending on the layer configuration, the type of polyolefin resin (B), the type of adhesive resin, the use and packaging form, the required physical properties, etc. The polyolefin resin (B) layer is usually 10 to 1000 μm, preferably 20 to 500 μm, and the adhesive resin layer is usually 1 to 30 μm, preferably 2 to 15 μm.
The thickness of the EVOH resin (A) layer is usually 1 to 30 μm, preferably 2 to 20 μm, particularly preferably 2 to 10 μm. If the thickness is too thin, sufficient gas barrier properties tend not to be obtained. On the contrary, if the thickness is too thick, the stretchability tends to be insufficient. The thickness structure of the EVOH resin layer and the polyolefin resin (B) layer is the polyolefin resin (B) when all the same resin layers are added together. The layer is thicker, and the ratio of the polyolefin resin (B) layer / EVOH resin layer is usually 1 to 100, preferably 10 to 50, in the ratio of the thickest layers.
In addition, the thickness structure of the EVOH resin layer and the adhesive resin layer is usually 0.1 to 100, preferably 0. The thickness ratio of the EVOH resin layer / adhesive resin layer is the thickest layer. 5-20.

Moreover, the thickness of the multilayer structure and multilayer hollow container after extending | stretching is 10-3000 micrometers normally, Preferably it is 100-1000 micrometers.
Moreover, the volume of a multilayer hollow container is 50mL-5L normally, Preferably it is 100mL-2L.

  The multilayer structure of the present invention is excellent in stretchability, and the stretched multilayer structure and multilayer hollow container obtained by stretching the multilayer structure are pharmaceutical containers, reagents and agricultural chemical containers, beverage containers, and food containers. It is useful for containers for toiletries, cosmetic containers, etc., especially because EVOH resin (A) and polyolefin resin (B) have similar stretch performance, or because they have excellent stretchability and appearance, It is particularly useful in fields where the clarity of containers is important, such as beverage containers, food containers, and cosmetic containers.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Example 1
As the EVOH resin (A), the 1,2-diol bond structure represented by the general formula (1a) is 1.5 mol%, the ethylene structural unit content is 38 mol%, and the saponification degree is 99.7 mol%. The saponified ethylene-vinyl acetate copolymer (A ′) (hereinafter sometimes referred to as EVOH resin (A ′)) having an MFR of 4 g / 10 min (210 ° C., load of 2160 g) was used.
Polypropylene resin (density (measured according to JIS K7112) 0.90 g / cm ³ , MFR 5.3 g / 10 minutes (measured according to JIS K7210)) is used as the polyolefin resin, and the general formula (2) As the amide compound represented, an amide compound (1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide)) in which n is 1 and R7 is a methyl group was used.

The polypropylene resin was charged into a twin screw extruder having a diameter of 30 mm and four mixing zones, and 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide) was 1500 ppm relative to the polypropylene resin (in the polypropylene resin). Both components were melt-kneaded by side charging with a powder feeder so that the amount of the components was 0.15% by weight. A polypropylene resin (B ′) containing 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide) (hereinafter, polypropylene resin (B ′)), which is extruded into strands and cut with a cutter. Columnar pellets were obtained.
Preset temperature of extruder: C1 / C2 / C3 / C4 / C5 / C6 / C7 / H / D = 200/210/230/230/230/230/230/230/230 ° C.

The EVOH resin (A ′) and the polypropylene resin (B ′) are supplied to a multi-layer extrusion apparatus equipped with a multi-layer T die having three types of feed blocks and five layers, and cooled by a chill roll in which cooling water circulates. A structure was obtained.
The structure of the multilayer structure is as follows: polypropylene resin (B ′) / adhesive resin (Mitsui Chemicals, “ADMER QF551”) / EVOH resin (A ′) / adhesive resin (Mitsui Chemicals, ADMER QF551 ") / polypropylene resin (B '), and the thickness (μm) was 360/45/90/45/360 μm, respectively.

Next, in order to evaluate the stretching performance of the multilayer structure, the following model experiment was performed.
Using a vacuum / pneumatic molding machine (manufactured by Asano Laboratories) that does not have a predetermined molding die, the multilayer structure is reheated at a heater temperature of 330 ° C. and a heating time of 34 to 44 seconds, and an air pressure of 0.2 kg. A pneumatic stretch was performed at / cm ² to obtain a balloon-like stretched multilayer structure.
In such a model experiment, by using a vacuum / pressure forming machine that does not have a predetermined molding die, a tension in a wider range than the tension applied to the multi-layered structure by an industrially performed stretching process. Is given. Therefore, the result obtained by this model experiment is a test method under stricter conditions than the actual industrial manufacturing method.

By observing the volume of the balloon-like stretched multilayer structure, it is possible to confirm the ability (stretchability) to stretch in response to a very strong tension. It can be said that the larger the volume, the higher the draw ratio and the better the drawability.
Further, by observing the disorder between the layers of the stretched multilayer structure, whether the multilayer structure can cope with a wide range of tensions respectively (stretching of EVOH resin (A) layer and polyolefin resin (B) layer) Whether the performance is approximate). For example, when the EVOH resin (A) layer and the polyolefin resin (B) layer have the same stretching speed, the interlayer interface does not deviate greatly, so that the interlayer disturbance does not occur. Also, the heating time is changed. By observing the above tendency, it can be seen how the multilayer structure can cope with a wide range of stretching conditions.

With respect to the stretched multilayer structure, stretchability (balloon volume) and appearance (interlayer disturbance) were evaluated as follows.
(Stretchability) Balloon volume of the stretched multilayer structure obtained above was measured and evaluated.
(Appearance) Balloons of the stretched multilayer structure obtained above were visually observed and evaluated according to the following criteria.
◎ ---- No cracks are observed on the side of the balloon.
○ −−− Some cracks are observed on the side of the balloon.
Δ ——— Many cracks are observed on the side surface of the balloon.
× −−− Cracks are remarkably observed on the side surface of the balloon.
The results are shown in Tables 1 and 2.

Comparative Example 1
A multilayer structure was obtained in the same manner as in Example 1 except that 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide) was not used, and the same evaluation was performed.
The results are shown in Tables 1 and 2.

Comparative Example 2 In Example 1, instead of 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide), instead of EVOH having a 1,2-diol bond structure represented by the general formula (1a) A multilayer structure was obtained in the same manner except that an unmodified EVOH resin was used, and the same evaluation was performed.
The results are shown in Tables 1 and 2.

From the above results, it was revealed that the multilayer structure of the present invention is excellent in stretchability, and the stretched multilayer structure obtained by stretching such a multilayer structure is excellent in appearance.
In Example 1, the appearance evaluation was good even when the heating time was changed, and very good evaluation was obtained at the heating time of 42 seconds and 44 seconds. However, in Comparative Example 1 in which 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide) was not blended with the polyolefin resin, some cracks were observed when the heating time was 42 seconds and 44 seconds. When the heating time was 38 seconds, significant cracks were observed. This is because, since the polyolefin resin contains 1,2,3-propanetricarboxylic acid tri (methylcyclohexylamide), the stretching performance of the polyolefin resin (B) layer approximates that of the EVOH resin (A) layer. This is presumably because the stretching speed was harmonized and no inter-layer disturbance occurred.

  From this model experiment, it is clear that the multilayer structure of the present invention exhibits a more excellent effect when the above-described various production methods are applied, and is particularly useful in the co-injection stretch blow molding method. became. And it is clear that the multilayer hollow container obtained by the co-injection stretch blow molding method is excellent in appearance, pharmaceutical container, reagent / agricultural container, beverage container, food container, toiletry container, cosmetic container It is useful for such as.

Claims (6)

A saponified ethylene-vinyl ester copolymer (A) layer having a 1,2-diol structural unit represented by the following general formula (1) and an amide compound represented by the following general formula (2) A multilayer structure comprising a polyolefin-based resin (B) layer and a (B) layer provided on at least one side of the (A) layer.

[In General Formula (1), R1, R2, and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bond chain, and R4, R5, and R6 each independently represent a hydrogen atom. Or an organic group is shown. ]

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ] The multilayer structure according to claim 1, wherein in the layer (B), the content of the amide compound represented by the general formula (2) is 0.001 to 5% by weight with respect to the polyolefin resin. 3. A stretched multilayer structure obtained by stretching the multilayer structure according to claim 1 or 2. The multi-layer hollow container according to claim 3, wherein the stretched multi-layer structure is a hollow container. In a method for producing a stretched multilayer structure by creating a multilayer structure comprising a polyolefin resin layer provided on at least one surface of a saponified ethylene-vinyl ester copolymer layer, stretching the multilayer structure,
The ethylene-vinyl ester copolymer saponified product layer is an ethylene-vinyl ester copolymer saponified product (A) layer having a 1,2-diol structural unit represented by the following general formula (1):

[In General Formula (1), R1, R2, and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bond chain, and R4, R5, and R6 each independently represent a hydrogen atom. Or an organic group is shown. ]
The method for producing a stretched multilayer structure, wherein the polyolefin resin layer is a polyolefin resin (B) layer containing an amide compound represented by the following general formula (2).

[In General Formula (2), n is 1 or 2, and R7 in the functional group α represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The functional groups α in the general formula (2) may be the same or different. ] 6. The manufacturing method according to claim 5, wherein the multilayer structure is manufactured by a co-injection molding method, the stretching method of the multilayer structure is a blow stretching method, and the stretched multilayer structure is a multilayer hollow container. A method for producing a multilayer hollow container, which is characterized in that it exists.