JPH07102129A - Polymer composition and laminate structural body - Google Patents

Abstract

PURPOSE:To obtain a polymer composition containing a specific ethylene-vinyl alcohol-based copolymer and a specific block copolymer in a specific ratio, excellent in gas barrier property, transparency, interlaminar peeling resistance and crease resistance and useful as a packaging material, etc. CONSTITUTION:The polymer composition contains (A) 55-97wt.% of an ethylene- vinyl alcohol-based copolymer having 20-60mol% ethylene content and (B) 45-3wt.% of a block copolymer having (i) a polymer block consisting of a polyamide having >=10mol% of a recurring unit consisting of either one unit in an amide unit of formula I and an amide unit of formula II (m is 0-10; n is 4-12; at least one of m and n is 4) and (ii) a polymer block consisting of one or more polymers among other polyamide, a polyester and a polycarbonate. Furthermore, the laminate structural body containing at least one layer among layers consisting of this composition is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene-vinyl alcohol copolymer composition and a laminated structure having a layer composed of the composition. In particular, the invention relates to ethylene-
The present invention relates to a polymer composition and a laminated structure having excellent gas barrier properties and transparency, which include a vinyl alcohol copolymer and a specific polyamide polymer product, and a laminate produced using the polymer composition of the present invention. The structure is particularly suitable for packaging films, sheets, containers and the like.

[0002]

2. Description of the Related Art Laminated film of aluminum foil and polyolefin film is widely used as a packaging material for retort due to its excellent gas barrier property, but it is opaque and inconvenient because the contents cannot be seen, and moreover, it cannot be heated in a microwave oven. There is a drawback that you cannot do it. Therefore, various transparent and gas-barrier packaging materials have been developed. As a typical example, polyvinylidene chloride film,
Examples thereof include metaxylene diamine-adipic acid condensate and other polyamide films, and polyvinylidene chloride-coated polyamide films.

However, although polyvinylidene chloride film has a high gas barrier property, it has haze and is not sufficiently transparent, and since it has a yellowish tint, it impairs the appearance of the contents to be packaged such as foods. It tends to reduce purchasing will. In addition, when high temperature treatment such as retort treatment is performed, there are drawbacks such that white opaqueness and deterioration of barrier properties occur. In the case of polyamide film and polyvinylidene chloride coated polyamide film, the barrier property against oxygen gas is low, and the transparent polyamide film packaging material used especially for skin pack packaging, shrink packaging, deep drawing packaging, rocket packaging, etc. is retorted. Since it is not suitable for heat treatment such as, the target of use is limited, and it is only used in foods distributed at low temperature.

On the other hand, the ethylene-vinyl alcohol copolymer is one of the thermoplastic resins having an extremely high gas barrier property, and by utilizing the gas barrier property, a semitransparent or opaque thick polypropylene layer is used as the inner and outer layers. An intermediate layer of an ethylene-vinyl alcohol-based copolymer is provided between them to form a thick hard laminate, and a cup or tray having a gas barrier property is produced by using it. However, when the ethylene-vinyl alcohol copolymer is used for a transparent thin film packaging material, when subjected to high-temperature heat treatment such as hot water high temperature heat sterilization and retort sterilization, the gas barrier property is significantly reduced, There is a drawback in that the ethylene-vinyl alcohol-based copolymer layer becomes cloudy or wrinkled, resulting in a markedly poor performance and appearance, which makes it unusable for practical use.

The above-mentioned abnormalities in the ethylene-vinyl alcohol copolymer layer are not less than 90 ° C., especially 12
It is presumed that when the copolymer is exposed to hot water of 0 ° C. or higher, water absorption and swelling of the copolymer occur, and at the same time, the copolymer melts and flows into an amorphous state. Therefore, as an improvement measure, blending an ethylene-vinyl alcohol-based copolymer with a polyamide-based resin, a polyolefin-based resin, a polyester-based resin, or a polycarbonate-based resin has been conventionally proposed in various ways, but some improvement can be seen. The effect is not sufficient, especially in a locally-sealed portion such as a heat-sealed portion and a bent portion in the packaging material, in the ethylene-vinyl alcohol copolymer composition accompanying re-aggregation of the blended resin. Since the whitening phenomenon due to the separation between the resin phases is likely to occur, further improvement is required.

[0006]

The object of the present invention is excellent in transparency and gas barrier property, and even when subjected to a high temperature treatment such as retort treatment, especially when heating or heating / pressurizing treatment using hot water or steam is performed. , Deterioration of gas barrier property, whitening due to phase separation from blended resin, opacity, etc. do not occur, and when laminated with other materials, there is no appearance defect such as delamination or wrinkle, and ethylene -Ethylene-vinyl alcohol-based copolymer composition capable of obtaining a film capable of maintaining excellent transparency and gas barrier properties inherent in the vinyl alcohol-based copolymer, good form and appearance, and the composition thereof Is to provide a laminated structure based on.

[0007]

As a result of various investigations by the present inventors, a block copolymerization having a specific polyamide polymer material, that is, a specific polyamide polymer block and a specific other polymer block is carried out. Coalescence, or a product obtained by melt-mixing a specific polyamide and a specific other polymer, using a polymer composition obtained by blending the ethylene-vinyl alcohol-based copolymer in a predetermined ratio,
It is possible to maintain good gas barrier properties, transparency, appearance, shape, etc. without deterioration of gas barrier properties, whitening, delamination, wrinkles, etc. even when subjected to high temperature heat treatment using hot water or steam. The present invention has been completed by finding that a film or a laminated structure can be obtained.

That is, the present invention has an ethylene content of 20.
A polymer composition containing 45 to 3% by weight of a block copolymer (B) with respect to 55 to 97% by weight of an ethylene-vinyl alcohol-based copolymer (A) of 60 to 60% by mole, The copolymer (B) has the following formula (I);

[0009]

Embedded image An amide unit represented by —NH— (CH ₂ ) ₅ —CO— (I) and the following formula (II);

[0010]

Embedded image —NH—CH ₂ — (CH ₂ ) m—CH ₂ —NH—CO— (CH ₂ ) n—CO— (II) (In the formula, m is an integer of 0 to 10 and n is 4 to A polymer block comprising a polyamide (b ₁ ) having 10 mol% or more of a repeating unit consisting of at least one of amide units represented by the integer 12 and at least one of m and n is 4. , A block copolymer having a polymer block composed of at least one polymer (b ₂ ) of other polyamides, polyesters and polycarbonates.

The present invention has an ethylene content of 20 to 6
A polymer composition containing 45 to 3% by weight of a melt-mixed product (C) with respect to 55 to 97% by weight of an ethylene-vinyl alcohol-based copolymer (A), which is 0 mol%, and which is melt-mixed. The product (C) has the following formula (I);

[0012]

Embedded image An amide unit represented by —NH— (CH ₂ ) ₅ —CO— (I) and the following formula (II);

[0013]

Embedded image _{-NH-CH 2 - (CH 2} ) m-CH 2 -NH-CO- (CH 2) n-CO- (II) ( wherein, m is an integer and n of 0 4 A polyamide (b ₁ ) having 10 mol% or more of repeating units consisting of at least one of the amide units represented by the integer 12 and at least one of m and n is 4)
And at least one polymer (b ₂ ) among other polyamides, polyesters, polycarbonates and block copolymers composed of two or more of these three compounds.
A polymer composition characterized by being a product obtained by melt-mixing at a temperature of 0 ° C. or higher, preferably 270 ° C. or higher. In this case, the upper limit of the temperature during melt mixing should be kept within the decomposition temperature of the polymer. The melt mixing is preferably performed under reduced pressure, for example, 40 mmHg or less, and further 10 mmHg or less. Furthermore, the present invention is a laminated structure having at least one layer made of such a polymer composition.

The ethylene-vinyl alcohol copolymer (hereinafter referred to as "EVOH copolymer") used as the component (A) in the polymer composition of the present invention is a saponified product of ethylene-vinyl ester copolymer. The ethylene unit is contained in an amount of 20 to 60 mol%, preferably 25 to 28 mol%. If the proportion of ethylene units is less than 20 mol%, the melt moldability of the polymer composition will be poor, while 60
If it exceeds mol%, the gas barrier property is deteriorated. Also, E
The saponification degree of the vinyl ester unit in the VOH-based copolymer is preferably 80% or more, more preferably 90% or more. When the saponification degree is less than 80%, the gas barrier property and the thermal stability are deteriorated. The melt flow index (MI; temperature 190 ° C .; measured at a load of 2160 g) as an EVOH-based copolymer is not limited, but a melting point near or above 190 ° C. is 2160 g under a load. Measured at a plurality of temperatures as described above, the reciprocal of absolute temperature was plotted on a semi-logarithmic graph as the horizontal axis and the melt index was plotted as the vertical axis. From the viewpoint of moldability, dispersibility of the blend, etc., it is preferable to use those of 0.5 g / 10 min to 20 g / 10 min.

The EVOH-based copolymer may have units derived from other copolymerizable monomers within a range (generally 10 mol% or less) within the range where the object of the present invention is not hindered. Examples of such monomers include olefins such as propylene, butylene, octene and dodecene; unsaturated carboxylic acids or their esters [eg (meth) acrylic acid or its alkyl esters such as methyl-, ethyl-esters] (Meth) acrylonitrile; (meth) acrylamides; vinylsilane (vinylalkoxysilane such as vinyltrimethoxysilane and vinyltriethoxysilane); vinylpyrrolidone such as N-vinylpyrrolidone; It may include a unit consisting of one or more of the monomers.

The EVOH copolymer may optionally contain a unit derived from a bifunctional or higher-functional polyfunctional monomer so that crosslinking by an electron beam or the like is promoted. Examples of the polyfunctional monomer in that case include triallyl cyanurate, triallyl isocyanurate, diallyl maleate, diallyl fumarate, diallyl phthalate, trimethylolpropane tri (meth) acrylate, tetraethylene glycol diacrylate and the like. Examples of the polyfunctional (meth) acrylic compound include The polyfunctional monomer can be copolymerized in the EVOH-based copolymer in any form such as ordinary copolymerization or graft polymerization. When the polyfunctional monomer is copolymerized, its proportion is preferably about 0.002 to 0.2 mol%. If necessary, a crosslinking aid such as zinc oxide, silicon dioxide, water or glycerin may be added.
It may be further contained in the VOH-based copolymer.

The polymer composition of the present invention has the above-mentioned E
It contains a block copolymer (B) or a melt-mixed product (C) together with a VOH-based copolymer. The block copolymer (B) includes an amide unit represented by the above formula (I) (that is, a capramide unit) [hereinafter referred to as "amide unit (I)"] and an amide unit represented by the above formula (II). [Hereinafter referred to as "amide unit (II)"] at least one of a polymer block made of a polyamide (b ₁ ) having a repeating unit of at least one of 10% by mole or more and another polyamide, polyester and polycarbonate. It is a block copolymer having a polymer block composed of _two polymers (b ₂ ).

At this time, when the block of the polyamide (b ₁ ) constituting the block copolymer has the amide unit (II) represented by the above formula (II), m and n in the formula (II) are Since at least one of 4 is 4, the amide unit (II) contains a structural unit derived from hexamethylenediamine, a structural unit derived from adipic acid, or a structural unit derived from both hexamethylenediamine and adipic acid. Always exists.

Ratio of amide units (I) and / or amide units (II) in polyamide (b ₁ ) [when both amide units (I) and amide units (II) are present, the total ratio of both) Is required to be 10 mol% or more, and if it is less than 10 mol%, the compatibility with the EVOH copolymer decreases. The proportion of the amide unit (I) and / or the amide unit (II) in the polyamide (b ₁ ) is 15 mol% or more, compatibility with the EVOH-based copolymer, retort resistance (whitening, delamination prevention) From the viewpoints of the above, 20 to 95 mol% is more preferable.

Examples of the polyamide (b ₁ ) include polycapramide (nylon 6), polyhexamethylene adipamide (nylon 6,6), polyethylene adipamide (nylon 2,6), polytetramethylene adipamide ( Nylon 4,6), polyhexamethylene sebacamide (nylon 6,10), polyhexamethylene dodecamide (nylon 6,12), polyoctamethylene adipamide (nylon 8,6), polydecanomethylene adipate Mido (nylon 1
0, 6), caprolactam / laurinlactam copolymer (nylon 6/12), caprolactam / ω-aminononane copolymer (nylon 6/9), caprolactam / hexamethylenediamine adipate copolymer (nylon 6
/ 6,6), laurinlactam / hexamethylenediamine adipate copolymer (nylon 12 / 6,6), hexamethylenediamine adipate / hexamethylenediamine sebacate copolymer (nylon 6,6 / 6,1)
0), ethylenediamine adipate / hexamethylenediamine adipate copolymer (nylon 2,6 / 6,
6), caprolactam / hexamethylenediamine adipate / hexamethylenediamine sebacate copolymer (nylon 6/6, 6/6, 10) and the like.

Of the polyamides listed above, when a polyamide having other amide units together with amide units (I) and / or amide units (II) is used, the proportion of the other amide units is 90 mol%. The following should be used. Among the above listed, polyamide (b ₁ )
Especially as polycapramide (nylon 6), polyhexamethylene adipamide (nylon 6,6), caprolactam / laurinlactam copolymer (nylon 6/12)
And a caprolactam / hexamethylenediamine adipate copolymer (nylon 6 / 6,6) is preferred.

As the polyamide (b ₁ ), 12
It is preferable to use one having a melting point or softening point of 0 ° C. or higher. If the melting point or softening point is less than 120 ° C., E
The compatibility with the VOH copolymer is not sufficient and the transparency is insufficient, and the transparency is lost when heat and pressure treatment (retort treatment etc.) is performed at 120 ° C or higher, and at the time of heat and pressure treatment. It becomes difficult to eliminate the whitening phenomenon that has occurred temporarily.

The polymer block composed of the other polymer (b ₂ ) constituting the block copolymer (B) is at least one polymer selected from the group consisting of polyamide, polyester and polycarbonate other than polyamide (b ₁ ). It consists of The polymer (b ₂ ) has a maximum melting point or softening point of 1 when it is hydrous at 120 ° C. until saturated.
It is preferable to use a polymer having a temperature of 20 ° C. or higher. If the melting point or softening point is lower than 120 ° C., the polymer composition is In this case, the transparency due to the interphase separation in (3) is lowered, and the whitening phenomenon that has temporarily occurred during the heat and pressure treatment is not eliminated and easily remains as it is.

When the block of the polymer (b ₂ ) is formed from a polyamide (other polyamide) other than the polyamide (b ₁ ), the relative viscosity thereof (1 g of the polyamide is dissolved in 100 ml of 96% sulfuric acid and 25 ° C. is used). Is 1.0 to
Preference is given to using 5 dl / g of polyamide.
More preferred is 5 to 4 dl / g of polyamide.

Other polyamides which can be used as the polymer (b ₂ ) include the above-mentioned amide unit (I) and / or amide unit (II) content of less than 10 mol%, preferably less than 5 mol%. Polylactams, polyamides composed of aliphatic diamines and aliphatic dicarboxylic acids, polyamides composed of lactams-aliphatic diamines-aliphatic dicarboxylic acids, and the like can be used. For example, polydodecanamide (nylon 12), polyundecane Examples thereof include amide (nylon 11), poly-ω-aminononanoic acid (nylon 9), poly-ω-aminoheptanoic acid (nylon 7) and the like.

In addition to the above-mentioned polyamide, a polyamide having a metaxylylene group can be preferably used as the polymer (b ₂ ). Examples of such a polyamide include metaxylylenediamine or metaxylylenediamine. 80 mol% or less (preferably 75 mol%
70 mol% or more (preferably 75 mol% or more) of a structural unit obtained by reacting a mixed xylylenediamine with para-xylylenediamine (below) with an α, ω-aliphatic dicarboxylic acid having 6 to 10 carbon atoms. The polyamides which it has can be mentioned. Specific examples include polymeta-xylylene adipamide, poly-meta-xylylene sebacamide, poly-meta-xylylene speramide, and meta-xylylene / para-xylene adipamide copolymer. These polyamides are used in a proportion of 30 mol% or less, aliphatic diamines such as hexamethylenediamine, alicyclic diamines such as piperazine, and para-bis- (2-aminoethyl).
Diamines having an aromatic nucleus such as benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as ε-caprolactam, ω-aminocarboxylic acids such as γ-aminoheptanoic acid, and para-aminomethylbenzoic acid. It may contain copolymerized units derived from aromatic aminocarboxylic acids such as

Further, in addition to the above-mentioned polyamide, an amorphous polyamide, that is, a polyamide which does not substantially show an endothermic crystal melting peak in DCS measurement and which is mainly composed of an aliphatic diamine and an aromatic dicarboxylic acid, is a polymer (b). It can be preferably used as ₂ ). In that case, examples of the aliphatic diamine constituting the amorphous polyamide include hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, and 2-methylpentanemethylene. Diamine, bis (4-aminohexyl) methane, 2,
2-bis (4-aminohexyl) isopropyridine,
1,4- (1,3) -diaminocyclohexane, 1,5
-Diaminopentane, 1,4-diaminobutane, 1,3
-Diaminopropane, 2-ethyldiamonobutane and the like can be mentioned, and one or more of these can be used. Among them, hexamethylenediamine, 2-methylpentanemethylenediamine, 1,5-diaminopentane, 1,4-diaminobutane and / or 1,3-diaminopropane are preferable.

Further, examples of the aromatic dicarboxylic acid constituting the above-mentioned amorphous polyamide include isophthalic acid, terephthalic acid, alkyl-substituted isophthalic acid, alkyl-substituted terephthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid and the like. And one or more of these aromatic dicarboxylic acids can be used. Among them, amorphous polyamides obtained from isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid and the like are preferable because they have excellent thermoformability, transparency and gas barrier property.

Specific examples of the amorphous polyamide include hexamethylenediamine / isophthalic acid polycondensate, hexamethylenediamine / isophthalic acid / terephthalic acid polycondensate, 2,24-trimethylhexamethylenediamine /
2,4,4-trimethylhexamethylenediamine / terephthalic acid polycondensate and the like can be mentioned. Among them, the molar ratio of isophthalic acid / terephthalic acid is 60/40 to 95.
A polycondensate of aromatic dicarboxylic acid having a ratio of / 5, particularly 65/35 to 90/10, and hexamethylenediamine is preferable.

When the block of the polymer (b ₂ ) is composed of polyester, it is preferable to use a polyester having an intrinsic viscosity of 0.2 to 2.0 dl / g. Preferred examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, poly (ethylene terephthalate / isophthalate), poly (ethylene glycol / cyclohexanedimethanol / terephthalate) and the like. These polyesters may optionally contain a small amount (generally 10 mol% or less) of a unit composed of another copolymerization component, and examples of such another copolymerization component include ethylene glycol, butylene glycol and cyclohexanedimethanol. , Diols such as neopentyl glycol and pentanediol, isophthalic acid, benzophenone dicarboxylic acid,] diphenyl sulfone dicarboxylic acid, diphenyl methane dicarboxylic acid, propylene bis (phenyl carboxylic acid), diphenyl oxide dicarboxylic acid,
Examples thereof include carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sabatic acid, and diethylsuccinic acid.

When the block of the polymer (b ₂ ) is made of polycarbonate, its intrinsic viscosity is 0.2.
It is preferable to use polycarbonate of about 2.0 dl / g. Preferred examples of polycarbonate include bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol P, bisphenol S,
There may be mentioned polycarbonates based on bisphenol Z, tetrachlorobisphenol A, tetrabromobisphenol A and the like.

The block copolymer (B) has a polymer block composed of the polyamide (b ₁ ) and a polymer block composed of the polymer (b ₂ ) in a weight ratio of 1/99 to 99/1. It is preferable that the weight ratio is 5/95 to 80/20. When the ratio of {polymer block composed of polyamide (b ₁ )} / {polymer block composed of polymer (b ₂ )} is less than 1/99, EVO
The compatibility with the H-based copolymer (A) becomes insufficient, the transparency is impaired, and the whitening phenomenon that occurs during high temperature heating such as retort treatment is eliminated and the phase separation of the polymer in the polymer composition is prevented. If the effect is not sufficiently exhibited, on the other hand, if it exceeds 99/1, the thermal stability becomes poor, and so-called fish eyes such as gels and spots occur during film formation, and the appearance tends to be poor.

In the block copolymer (B), as long as it has at least one polymer block made of the polyamide (b ₁ ) and at _{least one} polymer block made of the polymer (b ₂ ), each polymer block Is not limited, and the binding method of each polymer block is not particularly limited. For example,
Even if these two polymer blocks are linearly and alternately and randomly or taper-bonded, or one polymer is graft-polymerized and bonded to the other polymer, The polymer may be bound in a star shape.

The method for producing the block copolymer (B) is not particularly limited, and the block copolymer (B) can be produced by any method. For example, (1) the polyamide (b ₁ ) and the polymer (b ₂ ) can be produced in a polymerization tank. Or an extruder (preferably a twin-screw extruder) and put under reduced pressure in an oxygen-free atmosphere (for example, nitrogen atmosphere) for 24 hours.
A method for producing a block copolymer (B) by heating at a temperature of 0 to 340 ° C. for 5 to 100 minutes with stirring to cause an amide exchange reaction or a transesterification reaction between both polymers; (2) A method of graft-polymerizing a monomer for polymer (b ₂ ) onto polyamide (b ₁ ); (3) polymer (b
( ₂ ) A method in which a monomer for polyamide (b ₁ ) is graft-polymerized; (4) _One polymer of polyamide (b ₁ ) and polymer (b ₂ ) is produced, and then the other polymer is added to the end. It can be produced by employing a method in which the monomers for use are successively bonded and polymerized, and the method (1) above is particularly preferable. When the block copolymer (B) is produced by the method (1), the heating temperature is 240 to 340 ° C. depending on the types of the polyamide (b ₁ ) and the polymer (b ₂ ) used. Adjust by the range,
It is preferable to promote the transamidation reaction or transesterification reaction while preventing the decomposition of the polymer.

The polyamide (b ₁ ) and the polymer (b ₂ )
In a nitrogen atmosphere at 240 ° C. or higher (preferably 240 to 3
When the mixture is melt-mixed at a temperature of 40 ° C., a block copolymer may not be formed but a molten mixture of the polyamide (b ₁ ) and the polymer (b ₂ ) may be formed. A melt-mixed product [melt-mixed product (C)] can also be effectively used in the present invention in place of the block copolymer (B). By blending the melt-mixed product (C) with the EVOH-based copolymer (A), the transparency and the gas barrier property are excellent, and the gas barrier property is lowered even when subjected to a high temperature treatment such as a retort treatment. An excellent polymer composition free from whitening due to phase separation from the blended resin and delamination or wrinkling when laminated with other materials can be obtained. Therefore, the present invention relates to the EVOH copolymer (A) 5
The melt-mixed product (C) 45 to 5 to 97% by weight
It also includes a polymer composition containing 3% by weight, and a laminated structure having a layer made of the polymer composition.

A polymer composition in which only _one of the polyamide (b ₁ ) and the polymer (b ₂ ) is blended with the EVOH copolymer (A), and the EVOH copolymer (A) with the polyamide (b ₁ ). The polymer composition in which the polymer and the polymer (b ₂ ) are simply blended as they are is inferior in transparency and gas barrier property to the polymer composition of the present invention, and when subjected to high temperature treatment such as retort treatment. In addition, the gas barrier property is deteriorated, whitening occurs due to phase separation from the blended resin, delamination and wrinkling occur when laminated with other materials, and the excellent effects as in the present invention are not exhibited. Therefore, the excellent effect of the present invention, which is obtained by blending the block copolymer (B) or the melt-mixed product (C) with the EVOH copolymer (A), is a completely unexpected effect from this point of view. Can be said.

The polymer composition of the present invention may contain other polymers, stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, etc., if necessary. Additives can be included. For example, without limitation, stabilizers include calcium acetate, sodium acetate, zinc acetate, magnesium acetate, potassium acetate,
Lithium acetate, calcium stearate, sodium stearate, potassium stearate, magnesium stearate, zinc stearate, hydrotalcites,
Examples thereof include ethylenediaminetetraacetic acid. Examples of the antioxidant include 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis (6-t-butylphenol), 2,2 ′. -Methylene-bis (4-methyl-6-t
-Butylphenol), octadecyl-3- (3 ',
Examples thereof include 5'-di-t-butyl-4'-hydroxyphenyl) propionate and 4,4'-thiobis (6-t-butylphenol). Further, examples of the ultraviolet absorber include ethyl-2-cyano-3,3-diphenyl acrylate and 2- (2'-hydroxy-3'-t-
Butyl-5'-methylphenyl) benzotriazole,
2-hydroxy-4-methoxybenzophenone, 2,
2'-dihydroxy-4-methoxybenzophenone, 2
-Hydroxy-4-octoxybenzophenone and the like can be mentioned.

As the plasticizer, for example, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphoric acid ester, etc., and as the antistatic agent, pentaerythritol monostearate, sorbitan monopalmitate, etc. , Sulfated oleic acid, polyethylene oxide, carbowax and the like. Further, examples of the lubricant include ethylene bis stearamide, butyl stearate, and the like, and examples of the colorant include carbon black, phthalocyanine, quinacridone, azo pigments, titanium oxide, red iron oxide, and the like. Examples of the filler include glass fiber, asbestos, mica, sericite, talc, glass flake, ballastonite, calcium silicate, aluminum silicate, calcium carbonate, silicon oxide and montmorillonite.

Of the above, mica, talc,
1 to 6 of inorganic powder such as sericite and montmorillonite
The composition consisting of 0% by weight and 99 to 40% by weight of the polymer composition obtained by blending the EVOH copolymer (A) with the block copolymer (B) or the melt-mixed product (C) is a gas. It has better barrier properties and can be used very effectively for containers such as cups and trays.

The method for preparing the polymer composition of the present invention is not particularly limited, and any of the known methods conventionally used for preparing thermoplastic polymer compositions can be adopted. For example, the block copolymer (B) or the melt-mixed product (C) and, if necessary, other additives are dry-blended with the EVOH copolymer (A), and then a single-screw or twin-screw extruder is used. Then, the mixture is melt-kneaded, extruded, and then cut into an appropriate size to obtain a polymer composition having pellets or other shapes.

The polymer composition of the present invention can be molded by using a molding method and a molding apparatus generally adopted for a thermoplastic polymer or a composition thereof, such as extrusion molding, injection molding and blow molding. Various molded articles having arbitrary shapes and dimensions can be obtained by extrusion blow molding, injection blow molding, and the like. Among them, it is especially good to shape it into a film or sheet by extrusion molding,
It is preferable to use it as a laminated structure of such a film or sheet and another thermoplastic resin.

When the polymer composition of the present invention is used in a laminated structure, the number of layers and the type of other thermoplastic resin used in each layer are not particularly limited, but the thickness of the polymer composition of the present invention is about 5 to 250 μm, preferably about 10 to 100 μm
It is preferable that the intermediate layer has a certain degree, and the front surface and the back surface (inner and outer layers) thereof are made of another thermoplastic resin. The type of thermoplastic resin used for the inner and outer layers is not particularly limited, and can be appropriately selected in consideration of moisture permeability, heat resistance, heat sealability, transparency, etc., depending on the purpose and application of the laminated structure. , For example,
Polyethylene, polypropylene, cross-linked polypropylene,
Ethylene-polyvinyl acetate copolymers, partially saponified products thereof, ethylene- (meth) acrylic acid copolymers, ethylene- (meth) acrylic acid ester copolymers or other polyolefins or olefin copolymers, polyamides, polyesters, polystyrenes, Inner and outer layers made of polyvinyl chloride, acrylic polymer, polyvinylidene chloride, polyacetal, polycarbonate, etc. can be provided. In that case, the number of the inner and outer layers is not limited to one layer, and one or two or more of the above-mentioned various thermoplastic polymers may be combined to form three layers.
It may be a layer or a laminated structure having four or more layers.

The method for producing the laminated structure is not particularly limited, and any method such as a coextrusion method, a dry laminating method, a sand laminating method, an extrusion laminating method, a coextrusion laminating method or a solution coating method can be adopted to form the laminated structure. The body can be manufactured. In the case of producing a laminated structure by a coextrusion method, the layer made of the polymer composition of the present invention is positioned inside the laminated structure as an intermediate layer, and the above-mentioned thermoplastic resin for the inner and outer layers, an intermediate layer Resin for a binder for connecting the layer and the inner and outer layers (for example, a resin obtained by modifying an olefin resin such as a copolymer of polypropylene, polyethylene, ethylene and other monomers such as vinyl acetate and acrylic ester with maleic anhydride). Etc.) and the polymer composition of the present invention are conveniently coextruded in the form of a laminated film or sheet having a total of three or more layers. In that case, even if the extruded laminated film or sheet is cross-linked by electron beam irradiation, etc., if necessary, it is further stretched and thermoformed into a molded article of a predetermined shape (a packaging container or tray). Good.

In the case of producing a laminated structure by the dry lamination method, for example, a film is prepared in advance from the polymer composition of the present invention, and the film may be impregnated with a crosslinking aid if necessary. Alternatively, it is possible to employ a method in which the thermoplastic resin film coated with an adhesive is bonded and laminated using a heat roll or the like after irradiation with an electron beam to crosslink. The laminated structure obtained in that case may be crosslinked by electron beam irradiation or the like, if necessary, or may be further stretched and thermoformed into a molded article (a container for packaging, a tray, etc.) having a predetermined shape. .

In the above-mentioned laminated structure, electron beam irradiation is carried out at the resin stage before lamination, at the film stage before lamination, or after the laminated structure is produced to form the laminated structure. When the resin is crosslinked, the gas barrier property is improved, and it is possible to prevent whitening due to high temperature heat treatment such as retort treatment, separation between polymer phases, and delamination. Although not limited, an electron beam accelerator having an accelerating voltage of 100 to 3000 KV (for example, a scanning type device such as a pantograph type device, a curtain type device, an electro curtain type device, etc.) should be used as the electron beam source in that case. You can The irradiation dose may vary depending on the type of resin constituting the layer, the thickness of the laminated structure, the thickness of each layer, etc., but is generally 0.5 to 50 Mrad, preferably 1 to
It is recommended to set it to about 30 Mrad. If the irradiation dose is low, the gas barrier property will decrease, and whitening due to high temperature heat treatment such as retort treatment, separation between polymer phases, delamination, etc. will easily occur.On the other hand, if the irradiation dose is too high, stretching or thermoforming will occur. The moldability may be deteriorated, the strength of the laminated structure may be reduced, or the coloring may occur.

The laminated structure of the present invention comprising a layer composed of a polymer composition comprising the EVOH copolymer (A) and the block copolymer (B) or the melt-mixed product (C) is
It can be effectively used as various packaging materials in the form of a film or sheet, or can be subjected to secondary molding by any method such as press molding (drawing molding) or vacuum molding, and can be effectively used as various packaging materials, for example, lid materials and pouches. , Vacuum packaging material, skin pack material, deep drawing packaging material, rocket packaging material, cup, tray, bottle, tubular packaging material, and the like.

The above packaging material obtained from the laminated structure of the present invention can be subjected to high temperature heat treatment such as retort sterilization, boiling sterilization, etc., particularly high temperature heat treatment using hot water or steam. Its excellent gas barrier properties and transparency are not lost, and appearance defects such as delamination and wrinkles do not occur. In some cases, it may become white and slightly opaque immediately after heating the retort, but it is temporary and becomes transparent again if left for a while, especially when hot air of 40 to 150 ° C is heated after the retort heating. When used for drying treatment, its transparency and gas barrier properties are quickly restored, and it has an extremely high quality.

[0048]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In addition, in the following Examples and Comparative Examples, the gas barrier property of the laminated film (retort pouch) was measured by the following method. In addition, the presence or absence of fish eyes in the laminated film (retort pouch), transparency, and delamination (E
The presence or absence of a phenomenon that looks like dots in the VOH-based polymer layer or due to peeling or destruction between layers) is evaluated by visually observing the laminated film (retort pouch) obtained in each Example and Comparative Example, The evaluation was performed according to the evaluation criteria shown in Table 1 below.

Measurement of gas barrier property : A prototype multi-layer film was formed into a bag, and after containing the contents, retort treatment was performed under predetermined conditions, and then allowed to stand at 20 ° C. and 65% RH for a predetermined time, and thereafter. , Smashed the bag, made by Moconi "10/50
Type oxygen gas permeation measuring device "
The gas barrier property was measured under the humidity of 0% RH and external 65% RH.

[0050]

[Table 1] ○ fish eye of occurrence: Good: the number of generated laminated film 100cm ² per fish eye is less than 10 bad: laminated film 100cm ² per fisheye
50 or more ○ Transparency : Good: Completely transparent Poor: Low transparency Whiteness: Milky white with some transparency and whitening: Completely opaque white ○ Delamination : None: Opaque dots due to delamination No occurrence at all Minutes: 100 cm ² of opaque dots due to delamination
Less than 10 pieces per defect: 100 cm ² of opaque dots due to delamination
10 or more per

Example 1 (1) As a polyamide (b ₁ ), a caprolactam / laurin lactam copolymer (nylon 6/12) (6/1
2 = 90 mol% / 10 mol%; melting point 205 ° C.) (ENS
Manufactured by Guriron CR-9) 20 parts by weight and polylaurinlactam (nylon 12; as a polymer (b ₂ )).
(Melting point: 185 ° C.) (“L-16” manufactured by ENS) (80 parts by weight) is dry blended, and then reduced pressure-pressurization is repeated under a nitrogen atmosphere at 110 ° C. to sufficiently dissolve oxygen absorbed or absorbed in the polymer. After the removal, the mixture was put into a vent type twin-screw extruder under a nitrogen atmosphere, and melt-kneaded and extruded under reduced pressure (3 mmHg) at 300 ° C. for 15 minutes (average residence time). As a result, when examined by GPC and NMR, nylon 6/1
It was confirmed that the block copolymer (B) in which the polymer block of 2 and the polymer block of nylon 12 were bonded was produced. (2) EVOH copolymer [ethylene content 28 mol%,
Saponification degree 99.6%, MI (190 ° C, load 2160)
g) 1.3 g / 10 min] 80 parts by weight and 20 parts by weight of the block copolymer (A) produced in the above (1) are dry-blended, then put into a 30φ twin-screw extruder and melt-kneaded at 220 ° C. Extruded into strands and then cut to a diameter of 3
mm, 5 mm long pellets (polymer composition of the present invention)
Was manufactured.

(3) Using the pellets obtained in (2) above as a polymer composition for the intermediate layer, nylon 6 (“CM1021” manufactured by Toray Co .; for outermost layer), polypropylene (“Nobrene manufactured by Mitsubishi Petrochemical Co., Ltd.”) MA-6 "; for the innermost layer) and a maleic anhydride modified product of ethylene-vinyl acetate copolymer (" Admer QF-500 "manufactured by Mitsui Petrochemical Co., Ltd. for adhesive layer), 4-type 5-layer coextrusion device To polypropylene (60 μm; innermost layer) / adhesive resin layer (10 μm)
A laminated film composed of the above-mentioned (2) polymer composition layer (20 μm) / adhesive resin layer (10 μm) / nylon 6 layer (20 μm; outermost layer) was produced. (4) The gas barrier property of the laminated film obtained in (3) above was measured by the above-mentioned method, and the generation state of fish eyes and the transparency were examined according to the evaluation criteria in Table 1 above. It was as shown in 2.

(5) A retort pouch was prepared using the laminated film obtained in the above (3), and after filling it with water oil (salad oil content 10% by weight), it was heat-sealed at 180 ° C. and at 120 ° C. The retort sterilization treatment was performed with heated pressurized steam for 30 minutes. The delamination state and transparency immediately after the treatment were as shown in Table 2 below. Further, the gas barrier property after leaving for 3 hours after the treatment was as shown in Table 2, and the transparency after leaving for 12 hours was as shown in Table 2. (6) In the same manner as in (5) above, except that the retort sterilization treatment was performed at 120 ° C. for 60 minutes, the delamination state and transparency immediately after the treatment, the gas barrier property when left for 3 hours and the time when left for 12 hours When the transparency was examined, it was as shown in Table 2.

<Examples 2 to 5> Laminated in the same manner as in Example 1 except that the polymers shown in Table 2 below were used as the polyamide (b ₁ ) and the polymer (b ₂ ) in the proportions shown in Table 2. After producing the film, a retort pouch was produced and its physical properties were examined in the same manner as in Example 1. The results are shown in Table 2.
Shown in.

Example 6 The laminated film obtained in (3) of Example 1 was subjected to 5 Mra with an electron beam having an acceleration voltage of 300 KV.
The irradiation of d was performed. The physical properties of this laminated film and the physical properties of the retort pouch obtained therefrom were examined in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 1 Instead of using the block copolymer (B), polyamides shown in Table 2 below were used as EVO.
A H-copolymer (A) was blended alone to prepare a polymer composition, and a laminated film was manufactured in the same manner as in Example 1 except for the above, and then a retort pouch was prepared, and Example 1 was prepared.
The physical properties were examined in the same manner as. The results are shown in Table 2.

Comparative Examples 2 to 3 The EVOH copolymer similar to that used in Example 1 except that the ethylene content was 32 mol% was used as the EVOH copolymer, and the block copolymer (B) was used. Instead of using the above, polyamides shown in Table 2 below were blended alone into an EVOH copolymer to prepare a polymer composition, except that a laminated film was produced in the same manner as in Example 1, and then a retort pouch was formed. It was produced and examined for physical properties in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 4 80 parts by weight of the same EVOH copolymer (A) as used in Example 1 was added to 4 parts by weight of the same nylon 6/12 as used in Example 1 and nylon 12. 16 parts by weight of each of them were dry blended as they were, and thereafter, pellets were prepared by melt extrusion, a laminated film was prepared, and a retort pouch was prepared in the same manner as in Example 1, and the physical properties thereof were obtained in the same manner as in Example 1. I checked. The results are shown in Table 2.

[0059]

[Table 2]

From the results shown in Table 2 above, the weight of the present invention obtained by blending the EVOH copolymer (A) with the block copolymer (B) of the polyamide (b ₁ ) and the polymer (b ₂ ). It can be seen that when the combined composition is used, a laminated film having excellent transparency and gas barrier properties and no fish eye is obtained, and such excellent physical properties are maintained as they are after the retort treatment. . On the other hand, Comparative Examples 1 to 1 in which only _{one of} the polyamide (b ₁ ) and the polymer (b ₂ ) is blended with the EVOH-based copolymer (A)
2, Comparative Example 3 in which a polyamide other than the polyamide (b ₁ ) is blended in the EVOH copolymer (A), the polyamide (b ₁ ) and the polymer (b ₂ ) are simply used as they are in the EVOH copolymer (A). In the case of using the polymer composition of Comparative Example 4 blended in (4), the laminated film is inferior in gas barrier property and transparency, more fish eyes are generated, or before the retort treatment. It can be seen that the transparency, the gas barrier property, and the delamination property are significantly reduced after the retort treatment even though the physical properties of No. 1 are good.

[0061]

When the polymer composition of the present invention is used, it is excellent in transparency and gas barrier property, and is subjected to high temperature treatment such as retort treatment, particularly heating or heating / pressurizing treatment using hot water or steam. In the case of deterioration, deterioration of gas barrier property and whitening and opacity due to phase separation with blended resin do not occur, and appearance deterioration such as delamination and wrinkling occurs even when laminated with other materials. Without, EVO
It is possible to produce molded articles such as films and sheets capable of maintaining excellent transparency and gas barrier properties inherent to the H-based copolymer, good morphology and appearance, and further a laminated structure. A laminated structure having a layer made of a polymer composition (particularly a laminated film) can be extremely effectively used as a packaging material that requires heating or heating / pressurizing treatment using high-temperature hot water or steam such as a retort pouch. it can.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 77/00 LQS

Claims (3)

[Claims] 1. An ethylene-vinyl alcohol copolymer (A) 55-9 having an ethylene content of 20-60 mol%.
A polymer composition containing 45 to 3% by weight of the block copolymer (B) with respect to 7% by weight, wherein the block copolymer (B) has the following formula (I): NH- (CH _{2) 5} -CO- amide units and the following formula represented by (I) (II); embedded image _{-NH-CH 2 - (CH 2} ) m-CH 2 -NH-CO- An amide represented by (CH ₂ ) n-CO- (II) (wherein m is an integer of 0 to 10 and n is an integer of 4 to 12 and at least one of m and n is 4). A polymer block composed of a polyamide (b ₁ ) having at least one repeating unit composed of at least one of the units, and a polymer block composed of at least one polymer (b ₂ ) selected from other polyamides, polyesters and polycarbonates. Characterized by being a block copolymer having a united block Polymer composition. 2. An ethylene-vinyl alcohol copolymer (A) 55-9 having an ethylene content of 20-60 mol%.
A polymer composition containing 45 to 3% by weight of the melt-mixed product (C) with respect to 7% by weight, wherein the melt-mixed product (C) has the following formula (I); _{-NH- (CH 2) 5 -CO- (} I) represented by the amide units and the following formula (II); embedded image _{-NH-CH 2 - (CH 2} ) m-CH 2 -NH-CO _{- (CH 2) n-CO-} (II) ( wherein, m is an integer and n 0 to a 4 to 12 integer, at least one of m and n is 4) is represented by Polyamide (b ₁ ) having 10 mol% or more of repeating units consisting of at least one of amide units
And at least one polymer (b ₂ ) among other polyamides, polyesters, polycarbonates and block copolymers composed of two or more of these three compounds.
A polymer composition, which is a product obtained by melt-mixing at a temperature of 0 ° C. or higher. 3. A laminated structure having at least one layer comprising the polymer composition according to claim 1.