JP5008290B2 - Ethylene-vinyl alcohol copolymer composition and multilayer structure using the same - Google Patents

Description

  The present invention relates to a novel ethylene-vinyl alcohol copolymer composition and a multilayer structure using the same, and more specifically, a novel ethylene-vinyl alcohol copolymer having improved stretchability and excellent non-neck-in properties. The present invention relates to a polymer composition and a multilayer structure excellent in stability of gas barrier performance using the same.

In general, an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) is excellent in transparency, gas barrier properties, aroma retention, solvent resistance, oil resistance, and the like. It is used for various packaging materials such as materials, pharmaceutical packaging materials, industrial chemical packaging materials, and agricultural chemical packaging materials, and is heat-stretched for the purpose of adapting to applicable container shapes and improving its mechanical strength. In recent years, a multilayer stretched film containing EVOH has been frequently used, and the film forming speed and the stretching speed tend to increase in order to increase the productivity.
In the case of such high-speed film formation and high-speed stretching, EVOH having further improved stretchability and EVOH excellent in non-neck-in properties are required to obtain a stable film-forming film.

However, since E V O H is inferior in heat stretchability compared to polypropylene and polystyrene, 1) a method of adding a plasticizer to E V O H (see, for example, Patent Documents 1 and 2) and 2 ) A method of blending a polyamide-based resin (see, for example, Patent Documents 3 and 4) has been proposed, and on the other hand, 3) Resin using a combination of EVOH having a relatively good drawing performance and a low glass transition temperature. A method using a composition (for example, see Patent Documents 5 to 11), and 4) a method using an E V O H composition exhibiting a specific crystal melting behavior (for example, see Patent Document 12) and the like are also proposed. 5) A method for improving the heat stretchability at low temperature by adding an ethylene- (meth) acrylic acid copolymer to EVOH (see, for example, Patent Document 1 3). 6) Further, studies have been made to improve the thermoformability and stretchability of the container by grafting an epoxy compound to E V O H by a melting reaction (see, for example, Patent Documents 14 and 15). .)
Japanese Patent Application Laid-Open No. 5 3-8 8 67 Japanese Patent Application Laid-Open No. 5-9-20 3 4 5 Japanese Patent Application Laid-Open No. SHO 5 2-14 1 7 8 5 Japanese Patent Application Laid-Open No. 5-8-36412 Japanese Unexamined Patent Publication No. Sho 6 1-4 7 5 2 Japanese Patent Application Laid-Open No. Sho 6 0-1 7 3 0 3 8 Japanese Patent Application Laid-Open No. 63-196066. Japanese Patent Application Laid-Open No. Sho 6 3-2 3 057 5 JP-A-6 3-2 6 4 6 5 6 Japanese Patent Laid-Open No. 2-2 6 1 8 4 7 Japanese Patent Laid-Open No. 2 00 0-3 1 8 0 95 Japanese Laid-Open Patent Application No. 0-8-3 1 1 2 7 6 Japanese Patent Laid-Open No. 2 0 0 1-0 3 1 8 2 3 WO 02/0 9 2 6 4 3 Japanese Patent Laid-Open No. 2 03-3-3 2 7 6 1 9

  However, when the present inventor examined the above method in detail, the gas barrier property is lowered in the method 1), the long run melt formability is lowered in the method 2), and the heating is carried out in the method 3). Although some improvement in stretch moldability is recognized, the compatibility is not completely uniform because it is a blend of EVOH with different composition and structure, and phenomena such as surging and neck-in are seen depending on the extrusion conditions. The occurrence of surging and neck-in is also observed in the method 4) because EVOH having substantially different compositions is blended. In addition, although the formability at a relatively low temperature is improved by the method 5), it has been found that the long-run melt formability is lowered, and the phenomenon such as neck-in has not been studied at all. Since EVOH and an epoxy compound are reacted in a molten state, generation of miscellaneous side reaction products cannot be avoided, which may cause deterioration of long-run moldability and safety and health concerns. Such a phenomenon has not been studied at all. Therefore, there is a demand for a EVOH multilayer structure that is excellent in stretchability and non-neck-in property, and further has stable gas barrier performance after stretching.

（ここで、Ｘは炭素数が５以下のアルキレン基で、Ｒ１〜Ｒ４はそれぞれ独立して水素原子、又はアルキル基のいずれかであり、ｎは０または１を表す。）
Therefore, as a result of intensive research in view of the present situation, the present inventor has obtained two or more different types of E.
E V O H composition comprising V O H and having at least one E V O H having an ethylene content of 20 to 60 mol% and containing the following structural unit (1): Was found to meet the above-mentioned purpose, and the present invention was completed.

(Here, X is an alkylene group having 5 or less carbon atoms , R1 to R4 are each independently either a hydrogen atom or an alkyl group , and n represents 0 or 1.)

  The EVOH composition of the present invention contains two or more different EVOHs, and since at least one EVOH has a specific structural unit, the neck-in is small and stretched even when high-speed film formation is performed. It is possible to obtain a multilayer structure having excellent stretchability at the time and stable gas barrier performance after stretching.

Hereinafter, the present invention will be specifically described.
The EVOH composition of the present invention comprises two or more different EVOH, and at least one of them contains the structural unit (1), that is, a structural unit having a 1,2-glycol bond. E V O H.
First, E V O H (A) having the structural unit (1) will be described. In such EVOH (A), with respect to the bond chain (X) that bonds the main chain to the 1,2-glycol bond structure, alkylene is preferable as the bond type in terms of thermal melting stability, Alkylene having 5 or less carbon atoms is preferred. Further, in terms of good gas barrier performance of the resin composition, those having a smaller number of carbon atoms are preferable, and a structure in which a 1,2-glycol bond structure in which n = 0 is directly bonded to a molecular chain is most preferable. . The water atom regard R 1 ~ R 4, preferred because the alkyl group is easily available monomers, more preferably in that a good gas barrier properties of the hydrogen atom resin composition.

  The production method of EVOH (A) containing the structural unit (1) used in the present invention is not particularly limited, but a structural unit in which a 1,2-glycol bond structure is directly bonded to the main chain which is the most preferable structure is an example A method of saponifying a copolymer obtained by copolymerizing 3,4-diol-1-butene, a vinyl ester monomer and ethylene, 3,4-diacyloxy-1-butene, a vinyl ester monomer And a method of saponifying a copolymer obtained by copolymerizing ethylene, 3-acyloxy-4-ol-1-butene, a vinyl ester monomer and a copolymer obtained by copolymerizing ethylene A method for saponifying a copolymer obtained by copolymerizing 4-acyloxy-3-ol-1-butene, a vinyl ester monomer and ethylene, , 4-Diacyloxy-2-methyl-1-butene, a method of saponifying a copolymer obtained by copolymerizing a vinyl ester monomer and ethylene, 2,2-dialkyl-4-vinyl-1,3- Saponification of copolymer obtained by copolymerization of dioxolane, vinyl ester monomer and ethylene, and saponification of copolymer obtained by copolymerization of vinyl ethylene carbonate, vinyl ester monomer and ethylene And a method of decarboxylation. Moreover, as what has alkylene as a coupling chain (X), 4,5-diol- 1-pentene, 4, 5- diacyloxy-1-pentene, 4, 5-diol-3-methyl- 1-pentene, 4, Copolymers obtained by copolymerizing 5-diol-3-methyl-1-pentene, 5,6-diol-1-hexene, 5,6-diacyloxy-1-hexene and the like with vinyl ester monomers and ethylene The method of saponifying is mentioned. Among them, a method of saponifying a copolymer obtained by copolymerizing 3,4-diacyloxy-1-butene, a vinyl ester monomer and ethylene is preferable in terms of excellent copolymerization reactivity. It is preferable to use 3,4-diacetoxy-1-butene as -diasiloxy-1-butene. A mixture of these monomers may also be used. Further, 3,4-diacetoxy-1-butane, 1,4-diacetoxy-1-butene, 1,4-diacetoxy-1-butane and the like may be contained as a small amount of impurities. Moreover, although such a copolymerization method is demonstrated below, it is not limited to this.

（ここで、Ｒはアルキル基であり、好ましくはメチル基である。）

（ここで、Ｒはアルキル基であり、好ましくはメチル基である。）

（ここで、Ｒはアルキル基であり、好ましくはメチル基である。）
なお、上記の（２）式で示される化合物は、イーストマンケミカル社から、上記（３）式で示される化合物はイーストマンケミカル社やアクロス社の製品を市場から入手することができる。 The 3,4-diol-1-butene is represented by the following formula (2), and the 3,4-diacyloxy-1-butene is represented by the following formula (3), 3-acyloxy-4-ol-1-butene. Represents the following formula (4), and 4-acyloxy-3-ol-1-butene is represented by the following formula (5).

(Here, R is an alkyl group, preferably a methyl group.)

(Here, R is an alkyl group, preferably a methyl group.)

(Here, R is an alkyl group, preferably a methyl group.)
The compound represented by the above formula (2) can be obtained from Eastman Chemical Co., and the compound represented by the above formula (3) can be obtained from Eastman Chemical and Acros.

  Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, Examples thereof include vinyl versatate, among which vinyl acetate is preferably used.

  There are no particular limitations on the copolymerization of 3,4-diacyloxy-1-butene, vinyl ester monomer, and ethylene, and known methods such as bulk polymerization, solution polymerization, suspension polymerization, dispersion polymerization, or emulsion polymerization may be used. Although it can be employed, solution polymerization is usually performed.

The method for charging the monomer component at the time of copolymerization is not particularly limited, and any method such as batch charging, split charging, continuous charging, etc. may be employed.
In addition, as a method for introducing ethylene into the copolymer, ordinary ethylene pressure polymerization may be carried out, and the amount introduced can be controlled by the pressure of ethylene, and can be controlled according to the intended ethylene content. However, it is usually selected from the range of 25 to 80 kg / cm ² .

Examples of the solvent used for such copolymerization include usually lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone and methyl ethyl ketone, and methanol is preferably used industrially.
The amount of the solvent used may be appropriately selected in consideration of the chain transfer constant of the solvent in accordance with the degree of polymerization of the target copolymer. For example, when the solvent is methanol, S (solvent) / M ( Monomer) = 0.01 to 10 (weight ratio), preferably 0.05 to 7 (weight ratio).

In the copolymerization, a polymerization catalyst is used. Examples of the polymerization catalyst include known radical polymerization catalysts such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, lauryl peroxide, and t-butylperoxyneodeca Noate, t-butylperoxypivalate, α, α′bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3, -tetramethylbutylperoxyneodeca Peroxyesters such as noate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-hexylperoxypivalate, di-n-propylperoxydi Carbonate, di-iso-propyl peroxydicarbonate], di-sec- Til peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, dimethoxybutyl peroxydicarbonate, di Peroxydicarbonates such as (3-methyl-3-methoxybutylperoxy) dicarbonate, diacyl peroxides such as 3,3,5-trimethylhexanoyl peroxide, diisobutyryl peroxide, lauroyl peroxide, etc. Examples include low temperature active radical polymerization catalysts, and the amount of polymerization catalyst used varies depending on the type of catalyst and cannot be determined unconditionally, but is arbitrarily selected according to the polymerization rate. For example, when azobisisobutyronitrile or acetyl peroxide is used, 10 to 2000 ppm is preferable with respect to the vinyl ester monomer, and 50 to 1000 ppm is particularly preferable.
Moreover, it is preferable to select the reaction temperature of a copolymerization reaction from the range of 40 degreeC-boiling point with the solvent and pressure to be used.

  In the present invention, it is preferable to make the resin composition obtained by allowing the hydroxylactone compound or hydroxycarboxylic acid to coexist with the above catalyst to make the color tone good (close to colorless). The compound is not particularly limited as long as it has a lactone ring and a hydroxyl group, and examples thereof include L-ascorbic acid, erythorbic acid, glucono delta lactone, etc., preferably L-ascorbic acid and erythorbic acid are used. Examples of the hydroxycarboxylic acid include glycolic acid, lactic acid, glyceric acid, malic acid, tartaric acid, citric acid, salicylic acid, and the like, and preferably citric acid is used.

  The amount of the hydroxylactone compound or hydroxycarboxylic acid used is 0.0001 to 0.1 parts by weight, more preferably 0.0005 to 100 parts by weight of the vinyl ester monomer in both batch and continuous systems. 0.05 part by weight, particularly 0.001 to 0.03 part by weight is preferable. If the amount used is less than 0.0001 part by weight, the coexistence effect may not be sufficiently obtained. Exceeding part is not preferable because it results in inhibiting the polymerization of the vinyl ester monomer. In preparing such a compound in a polymerization system, there is no particular limitation, but usually an aliphatic ester (methyl acetate, ethyl acetate) containing a lower aliphatic alcohol (methanol, ethanol, propanol, tert-butanol, etc.) or a vinyl ester monomer. Etc.), a solvent such as water, or a mixed solvent thereof, and charged into the polymerization reaction system.

  In addition, what is necessary is just to determine the preparation amount of 3, 4- diacyloxy 1-butene etc. according to the introduction amount of said structural unit (1) desired.

  In the present invention, an ethylenically unsaturated monomer that can be copolymerized may be copolymerized as long as the effects of the present invention are not impaired during the above copolymerization. Examples of such monomers include propylene, 1 -Olefins such as 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, or those having 1 to 18 carbon atoms Mono- or dialkyl esters, acrylamide, N-alkyl acrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salt, acrylamidopropyldimethylamine or its acid salt or its quaternary salt, etc. Acrylamides, methacrylamide, N-alkyl methacryl having 1 to 18 carbon atoms Methacrylamides such as amide, N, N-dimethylmethacrylamide, 2-methacrylamide propanesulfonic acid or salts thereof, methacrylamide propyldimethylamine or acid salts thereof or quaternary salts thereof, N-vinylpyrrolidone, N-vinylformamide N-vinylamides such as N-vinylacetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers, alkoxyalkyl vinyl ethers, vinyl chloride, vinylidene chloride , Vinyl halides such as vinyl fluoride, vinylidene fluoride, vinyl bromide, vinyl silanes, allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3- Acrylamide-3-dimethylpropyl) - ammonium chloride, acrylamido-2-methylpropanesulfonic acid, glycerol monoallyl ether, ethylene carbonate, and the like.

  Furthermore, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 2-hydroxy-3- Cationic group-containing monomers such as methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3-butenetrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, acetoacetyl group-containing monomers And so on.

  Further, vinyl silanes include vinyl trimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylisobutyldimethoxysilane, vinylethyldimethoxysilane, vinylmethoxydioxysilane. Butoxysilane, vinyldimethoxybutoxysilane, vinyltributoxysilane, vinylmethoxydihexyloxysilane, vinyldimethoxyhexyloxysilane, vinyltrihexyloxysilane, vinylmethoxydioctyloxysilane, vinyldimethoxyoctyloxysilane, vinyltrioctyloxysilane , Vinylmethoxydilauryloxysilane, vinyldimethoxylauryloxysilane, vinylmethoxydioleoxysilane And vinyl dimethoxy I acetoxyphenyl silane.

  The obtained copolymer is then saponified. In such saponification, an alkali catalyst or an acid catalyst is used in a state where the copolymer obtained above is dissolved in alcohol or hydrous alcohol. Done. Examples of the alcohol include methanol, ethanol, propanol, tert-butanol and the like, and methanol is particularly preferably used. The concentration of the copolymer in the alcohol is appropriately selected depending on the viscosity of the system, but is usually selected from the range of 10 to 60% by weight. Catalysts used for saponification include alkali catalysts such as alkali metal hydroxides and alcoholates such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, lithium methylate, etc., sulfuric acid, Examples include acid catalysts such as hydrochloric acid, nitric acid, metasulfonic acid, zeolite, and cation exchange resin.

The amount of the saponification catalyst used is appropriately selected depending on the saponification method, the target degree of saponification, and the like. Usually, when an alkali catalyst is used, a vinyl ester monomer and 3,4-diacyloxy-1- 0.001-0.1 equivalent with respect to the total amount of monomers, such as butene, Preferably 0.005-0.05 equivalent is suitable. With regard to such a saponification method, batch saponification, continuous saponification on a belt, and continuous saponification of a tower type are possible depending on the target degree of saponification, etc. For reasons such as efficiency and ease of progress, tower saponification under constant pressure is preferably used. The pressure during saponification cannot be generally specified depending on the target ethylene content, but is selected from the range of ^{2 to} 7 kg / cm ² , and the temperature at this time is 80 to 150 ° C., preferably from 100 to 130 ° C. Selected.

Thus, EVOH (A) having the above structural unit (1) (structural unit having a 1,2-glycol bond) is obtained. In the present invention, the obtained EVOH ( the ethylene content and the saponification degree of a) is not particularly limited, an ethylene content of 2 0-6 0 mol% (2 5-4 8 mol%, especially), a degree of saponification 9 0 mol% It is preferable that the ethylene content is less than 10% by mole, and the molded product obtained, particularly a stretched film, tends to deteriorate the gas barrier property and appearance at high humidity. On the other hand, if it exceeds 60 mol%, the gas barrier property of the stretched film tends to decrease, and if the degree of saponification is less than 90 mol%, the gas barrier property and moisture resistance of the stretched film tend to decrease.

Further, the amount of the structural unit having a 1,2-glycol bond introduced into EVOH (A) is not particularly limited, but is 0.1 to 50 mol%, more preferably 0.5 to 40 mol%, The amount of introduction is preferably less than 0.1 mol%, and if the amount introduced is less than 0.1 mol%, the effect of the present invention is not sufficiently exhibited. Further, in adjusting the amount of structural units having 1,2-glycol bonds, it is also possible to adjust by blending at least two types of EVOH having different introduction amounts of structural units having 1,2-glycol bonds. . Further, at least one of them may not have a structural unit having a 1,2-glycol bond. With regard to EVOH in which the 1,2-glycol bond amount is adjusted in this way, the 1,2-glycol bond amount can be calculated by weight average, and the ethylene content can also be calculated by weight average. However, precisely, the ethylene content and the 1,2-glycol bond amount can be calculated from the measurement result of ¹ H-NMR described later.

  EVOH (A) having the structural unit (1) obtained by such a method can be used as it is, but furthermore, within the range not impairing the object of the present invention, acids such as acetic acid and phosphoric acid, and alkali metals thereof, It is preferable to add a metal salt such as an alkaline earth metal or a transition metal, and to add boric acid or a metal salt thereof as a boron compound from the viewpoint of improving the thermal stability of the resin.

The amount of acetic acid added is 0.001 to 1 part by weight (more preferably 0.005 to 0.2 part by weight, particularly 0.010 to 0.1 part by weight) with respect to 100 parts by weight of EVOH (A). If the amount added is less than 0.001 part by weight, the content may not be sufficiently obtained. On the other hand, if the amount added exceeds 1 part by weight, the appearance of the resulting molded product tends to deteriorate. .
Metal borate salts include calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), aluminum borate / potassium borate, ammonium borate (ammonium metaborate, ammonium tetraborate, pentaborate) Ammonium phosphate, ammonium octaborate, etc.), cadmium borate (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate (potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, octaborate) Potassium), silver borate (silver metaborate, silver tetraborate, etc.), copper borate (cupric borate, copper metaborate, copper tetraborate, etc.), sodium borate (sodium metaborate, two Sodium borate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.), boric acid (Lead metaborate, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, barium metaborate, two Barium borate, barium tetraborate, etc.), bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.), manganese borate ( (Manganese borate, manganese metaborate, manganese tetraborate, etc.), lithium borate (lithium metaborate, lithium tetraborate, lithium pentaborate, etc.), borax, carnite, inioite, and goethite , Borate minerals such as suian stone, zaiberite and the like, preferably borax, C acid, sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate acid, eight sodium borate, etc.). Moreover, as an addition amount of a boron compound, 0.001-1 weight part (further 0.002-0.2 weight part, especially 0.005-0 in conversion of boron with respect to 100 weight part of all EVOH in a composition). .1 part by weight), and if the amount added is less than 0.001 part by weight, the effect of the content may not be sufficiently obtained. It is not preferable because it tends to deteriorate.

  Such metal salts include sodium, potassium, calcium, magnesium, and other organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid, sulfuric acid, sulfurous acid, carbonic acid, and phosphoric acid. And metal salts of inorganic acids such as acetate, phosphate and hydrogen phosphate are preferred. Further, the addition amount of the metal salt is 0.0005 to 0.01 parts by weight (more preferably 0.001 to 0.05 parts by weight, particularly 0) with respect to 100 parts by weight of the total EVOH in the composition. 0.0002 to 0.03 parts by weight), and if the amount added is less than 0.0005 parts by weight, the content may not be sufficiently obtained. The appearance of the resulting molded product tends to deteriorate, which is not preferable. In addition, when adding 2 or more types of alkali metal and / or alkaline-earth metal salt to EVOH, it is preferable that the total is in the range of said addition amount.

  The method for adding acids or metal salts thereof to EVOH (A) is not particularly limited. A) A porous precipitate of EVOH (A) having a water content of 20 to 80% by weight is converted into an aqueous solution of acids or metal salts thereof. A method in which the acid or its metal salt is added and then dried, and a) a uniform solution (water / alcohol solution, etc.) of EVOH (A) is mixed with the acid or its metal salt, and then in the coagulation liquid Extruded into strands, then cut the resulting strands into pellets and further dried, c) EVOH (A) and acids and their metal salts are mixed together and then melted in an extruder etc. Method of kneading d) During the production of EVOH (A), the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step is neutralized with acids such as acetic acid, and the remaining acids such as acetic acid By-product sodium acetate Potassium, the quantity of alkali metal salts such as potassium acetate may be a method like or to adjust the water washing treatment. In order to obtain the effects of the present invention more remarkably, the methods a), b) and d), which are excellent in dispersibility of acids and metal salts thereof, are preferred. Further, the acids, their metal salts and boron compounds may be added after mixing different EVOH. Moreover, you may blend EVOH composition containing this additive and EVOH which does not contain.

The EVOH composition (A) obtained by the above methods a), b) or d) is dried after salts and metal salts are added.
As such a drying method, various drying methods can be employed. For example, fluidized drying in which substantially pellet-like EVOH is stirred and dispersed mechanically or with hot air, or substantially pellet-like EVOH is not subjected to dynamic actions such as stirring and dispersion. Examples of dryers for fluidized drying include cylindrical / groove-type stirred dryers, circular tube dryers, rotary dryers, fluidized bed dryers, vibrating fluidized bed dryers, and conical rotations. In addition, as a dryer for performing stationary drying, a batch type box dryer is used as a stationary material type, a band dryer, a tunnel dryer, and a vertical dryer are used as a material transfer type. Although a vessel etc. can be mentioned, it is not limited to these. It is also possible to combine fluidized drying and stationary drying.

  Air or an inert gas (nitrogen gas, helium gas, argon gas, etc.) is used as the heating gas used in the drying process, and the temperature of the heating gas is 40 to 150 ° C., which is the productivity and the heat of EVOH. It is preferable in terms of preventing deterioration. The time for the drying treatment is usually from about 15 minutes to 72 hours, although it depends on the water content of EVOH and the amount of treatment, from the viewpoint of productivity and prevention of thermal degradation of EVOH.

  The EVOH composition (A) is dried under the above conditions. The water content after the drying treatment is 0.001 to 5% by weight (more preferably 0.01 to 2% by weight, especially 0.1%). It is preferable that the water content is less than 0.001% by weight. If the water content is less than 0.001% by weight, long-run moldability tends to decrease. Is not preferable.

  Thus, the EVOH composition (A) of the present invention can be obtained. In such an EVOH composition (A), some monomer residue (3,4-diol- 1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-ol-1-butene, 4-acyloxy-3-ol-1-butene, 4,5-diol-1-pentene, 4, 5-diacyloxy-1-pentene, 4,5-diol-3-methyl-1-pentene, 4,5-diol-3-methyl-1-pentene, 5,6-diol-1-hexene, 5,6- Diacyloxy-1-hexene, 4,5-diacyloxy-2-methyl-1-butene, etc.) and saponified monomers (3,4-diol-1-butene, 4,5-diol-1-pentene, 4,5 -Diol 3-methyl-1-pentene, 4,5-diol-3-methyl-1-pentene, it may also contain a 5,6-diol-1-hexene, etc.).

  Although it does not specifically limit about the melt flow rate (MFR) (210 degreeC, load 2160g) of EVOH composition (A) obtained by the above-mentioned method, 0.1-100 g / 10min (Further 0.5- 50 g / 10 min, particularly 1 to 30 g / 10 min) is preferable, and when the melt flow rate is smaller than the range, the inside of the extruder tends to be in a high torque state at the time of molding, and the extrusion process tends to be difficult. If it is larger than the above range, the appearance and gas barrier properties at the time of heat-stretching molding tend to decrease, which is not preferable.

The EVOH composition of the present invention contains EVOH (A) containing the structural unit of the above (1) as described above and EVOH (B) different from this, and examples of such EVOH (B) include EVOH ( Examples thereof include those having different structural units from A), those having different ethylene contents, those having different degrees of saponification, and those having different molecular weights.
Examples of EVOH (B) having a structural unit different from EVOH (A) include, for example, EVOH consisting only of an ethylene structural unit and a vinyl alcohol structural unit, and a modified EVOH having a functional group such as a 2-hydroxyethoxy group in the side chain of EVOH. Can be mentioned.
When EVOH (B) is different from EVOH (A) in ethylene content, the structural unit may be the same or different, but the ethylene content difference is 1 mol% or more (further, Is preferably 2 mol% or more, particularly 2 to 20 mol%). If the ethylene content difference is too large, the stretchability may be poor, which is not preferable.
When EVOH (B) is different from EVOH (A) in saponification degree, the saponification degree difference is preferably 2 mol% or more, and when the molecular weight is different, the difference is MFR. It is preferable that it is 1.0 or more.

  The blending method for obtaining the EVOH composition of the present invention is not particularly limited, and each EVOH is dissolved in a solvent such as water-alcohol or dimethyl sulfoxide and mixed in a solution state. A method in which the ethylene-vinyl acetate copolymer before conversion is dissolved in an alcohol solvent such as methanol and mixed at the same time, or each EVOH or an EVOH composition in which various additives are blended is melt mixed. In general, a melt mixing method is employed.

  As such a melt mixing method, for example, a known kneading apparatus such as a kneader ruder, an extruder, a mixing roll, a Banbury mixer, a plast mill, etc. can be used. Usually, a single-screw or twin-screw extruder is used. It is industrially preferable to use it, and it is also preferable to provide a vent suction device, a gear pump device, a screen device, etc. as needed. In particular, in order to remove moisture and by-products (such as pyrolytic low molecular weight substances), one or more vent holes are provided in the extruder and suction is performed under reduced pressure, or oxygen is prevented from entering the extruder. Therefore, by continuously supplying an inert gas such as nitrogen into the hopper, an EVOH composition having excellent quality with reduced thermal coloring and thermal deterioration can be obtained.

  Further, the method for supplying each EVOH or a composition thereof to the extruder is not particularly limited. (A) Before each EVOH is supplied to the extruder, it is blended in advance (such as the above-mentioned solution mixing or pre-saponification mixing). B) A method of dry blending each EVOH and supplying it to the extruder in a batch. C) Supplying one or more types of EVOH to the extruder and melting them to supply another EVOH in a solid state. A method (solid side feed method), and d) a method in which one or more types of EVOH are supplied to an extruder and melted to supply another EVOH in a molten state (melt side feed method). Of these, the method (b) is industrially practical in terms of the simplicity of the apparatus and the cost of the blend.

The blending ratio of EVOH (A) having the structural unit (1) and EVOH (B) different from this is not particularly limited, but is 0.05 to 200, more preferably 0.1 to 100 by weight. Specifically, the weight ratio is EVOH (A) / EVOH (B) = 99.5 / 0.5 to 0.05 / 99.5 (further 99/1 to 1/99), If the blending ratio is too large or too small, the gas barrier property or stretchability is lowered, which is not preferable.
Moreover, when there are a plurality of EVOH (B) different from EVOH (A), the sum of them may be considered as the weight of EVOH (B).

The 1,2-glycol content in the EVOH composition of the present invention can be calculated from the average content of each component of the entire composition, and more specifically, the ¹ H-NMR described later. Calculated from the measurement results. The average content is preferably 0.1 to 30 mol% (more preferably 0.5 to 20 mol%, particularly 1 to 10 mol%). However, if the amount exceeds 30 mol%, the gas barrier property tends to decrease, which is not preferable.

  The EVOH composition of the present invention thus obtained is further added to a saturated aliphatic amide (such as stearic acid amide), an unsaturated fatty acid amide (such as oleic acid amide), bis, etc., as long as the object of the present invention is not impaired. Fatty acid amide (for example, ethylene bis-stearic acid amide), fatty acid metal salt (for example, calcium stearate, magnesium stearate, etc.), low molecular weight polyolefin (for example, low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or low molecular weight polypropylene, etc.) Lubricants, inorganic salts (for example, hydrotalcite), plasticizers (for example, aliphatic polyhydric alcohols such as ethylene glycol, glycerin, hexanediol), oxygen absorbers (for example, reduced iron powders as inorganic oxygen absorbers) In addition to this, water-absorbing substances and electrolytes are added. Minium powder, potassium sulfite, photocatalytic titanium oxide and the like are organic compound-based oxygen absorbers such as ascorbic acid, fatty acid esters and metal salts thereof, hydroquinone, gallic acid, polyhydric phenols such as hydroxyl group-containing phenol aldehyde resin, bis -Coordination conjugate of nitrogen-containing compound and transition metal such as salicylaldehyde-imine cobalt, tetraethylenepentamine cobalt, cobalt-Schiff base complex, porphyrins, macrocyclic polyamine complex, polyethyleneimine-cobalt complex, terpene compound, A reaction product of amino acids and a hydroxyl group-containing reducing substance, a triphenylmethyl compound, or the like as a polymer oxygen absorber is a coordinated conjugate of a nitrogen-containing resin and a transition metal (eg, a combination of MXD nylon and cobalt). , Blends of tertiary hydrogen-containing resins and transition metals (E.g., a combination of polypropylene and cobalt), a blend of a carbon-carbon unsaturated bond-containing resin and a transition metal (e.g., a combination of polybutadiene and cobalt), a photo-oxidatively disintegrating resin (e.g., a polyketone), an anthraquinone polymer (Example: Polyvinylanthraquinone) etc., and these compounds added with photoinitiators (benzophenone, etc.), peroxide supplements (commercial antioxidants, etc.) and deodorants (activated carbon, etc.)) , Heat stabilizers, light stabilizers, antioxidants, UV absorbers, colorants, antistatic agents, surfactants, antibacterial agents, antiblocking agents, slip agents, fillers (eg inorganic fillers), other resins ( For example, polyolefin, polyamide, etc.) may be blended.

Thus, although the EVOH composition of the present invention is obtained, such an EVOH composition is useful for a molded product, particularly useful for melt molding, and such melt molding will be described below.
Examples of the molded product include single-layered or multilayered (laminated) films, sheets, containers, tubes, and the like, and examples of the laminating method when laminating with other base materials include the film of the EVOH composition of the present invention. , A method of melt extrusion laminating another substrate on a sheet, a method of melt extrusion laminating the resin to another substrate, a method of coextruding the resin and another substrate, and the resin (layer) And other base materials (layers) may be dry-laminated using known adhesives such as organic titanium compounds, isocyanate compounds, polyester compounds, polyurethane compounds, etc. In particular, a method of co-extrusion is preferable.

  As the co-extrusion method, specifically, a known method such as a multi-many hold die method, a feed block method, a multi-slot die method, or a die external bonding method can be employed. As the shape of the die, there are a T die and a round die, and the T die is preferable in that the stretchability can be further improved by quenching immediately after film formation. The film forming speed is preferably 10 to 200 m / min from the viewpoint of productivity and stability of film properties. The melt molding temperature during melt extrusion is preferably 150 to 300 ° C.

  As such other base materials, thermoplastic resins are useful. Specifically, linear low density polyethylene, low density polyethylene, ultra-low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer Polymer, ionomer, ethylene-propylene (block and random) copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) ) Polyolefin resins and polyesters in a broad sense, such as copolymers, polybutenes, polypentenes and other olefins or copolymers, or those olefins alone or copolymers grafted with unsaturated carboxylic acids or esters thereof Resin, polyamide resin (including copolyamide) ), Polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, aromatic or aliphatic polyketone, and reduction of these Polyalcohols, and other EVOH, etc., but from the viewpoint of practicality such as physical properties (particularly strength) of the multilayer structure, polypropylene, ethylene-propylene (block or random) copolymer, polyamide, polyethylene , Ethylene-vinyl acetate copolymer, polystyrene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) are preferably used.

  Furthermore, when the other substrate is extrusion coated on a molded product such as a film, sheet or stretched film of the EVOH composition of the present invention, or a film or sheet of another substrate is laminated using an adhesive, it takes. As the base material, any base material (paper, metal foil, uniaxial or biaxially stretched plastic film or sheet and its inorganic deposit, woven fabric, non-woven fabric, metallic cotton, wood, etc.) can be used in addition to the thermoplastic resin. It can be used.

  The layer structure of the multilayer structure is such that the EVOH composition layer of the present invention is a (a1, a2,...) And another base material, for example, a thermoplastic resin layer is b (b1, b2,...). If it is a film, sheet or bottle, not only a / b two-layer structure, but also b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / Arbitrary combinations such as b1 / a / b1 / b2, b2 / b1 / a / b1 / a / b1 / b2, etc. are possible. Furthermore, a regrind layer comprising at least a mixture of the EVOH composition and a thermoplastic resin is provided. When R, b / R / a, b / R / a / b, b / R / a / R / b, b / a / R / a / b, b / R / a / R / a / R / B and the like, and in the filament form, a and b are bimetal type, core (a) -sheath (b) type, core (b) -sheath (a) type, or Any combination Kokoroshinsaya type or the like are possible. In the above layer structure, an adhesive resin layer can be provided between the respective layers as necessary, and various adhesive resins can be used, and the stretchability is excellent. It is preferable in that a multilayer structure can be obtained, and differs depending on the type of resin b. It cannot be generally stated, but an unsaturated carboxylic acid or its anhydride is added to an olefin polymer (the above-mentioned broadly defined polyolefin resin) by addition reaction or grafting. Examples thereof include modified olefin polymers containing a carboxyl group obtained by chemical bonding by reaction or the like. Specifically, 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-modified ethylene anhydride - one or a mixture of two or more species selected from vinyl acetate copolymers and the like as preferred. At this time, the amount of the unsaturated carboxylic acid or anhydride thereof contained in the thermoplastic resin is preferably 0.001 to 3% by weight, more preferably 0.01 to 1% by weight, particularly preferably 0.03. ~ 0.5 wt%. If the amount of modification in the modified product is small, the adhesiveness may be insufficient. On the other hand, if the amount is too large, a crosslinking reaction may occur and the moldability may be deteriorated. Further, these adhesive resins can be blended with the EVOH composition of the present invention, other EVOH, rubber / elastomer components such as polyisobutylene, ethylene-propylene rubber, and the resin of the b layer. In particular, blending a polyolefin resin different from the base polyolefin resin of the adhesive resin is useful because the adhesiveness may be improved.

  The thickness of each layer of the multilayer structure cannot be generally stated depending on the layer configuration, the type of b, the application and container form, the required physical properties, etc., but usually the a layer is 2 to 500 μm (further 3 to 200 μm), The b layer is selected from a range of about 10 to 5000 μm (more preferably 30 to 1000 μm) and the adhesive resin layer is about 1 to 400 μm (further 2 to 150 μm).

  The base resin layer may contain an antioxidant, an antistatic agent, a lubricant, a core material, an antiblocking agent, an ultraviolet absorber, a wax and the like as conventionally known.

  When the multilayer structure thus obtained is stretched, it may be either uniaxial stretching or biaxial stretching, and it is better in terms of physical properties to perform stretching as high as possible. In the case of uniaxial stretching, it is preferably 5 times or more, particularly 10 times or more, and in the case of biaxial stretching, the area magnification is preferably 5 times or more, particularly preferably 10 times or more, but in the present invention, the area magnification is 20 times. It is also possible to make it at least twice, particularly 24 to 50 times. Even at this time, a stretched film or stretched sheet that does not cause pinholes, cracks, stretch unevenness, etc. during stretching can be obtained.

  As the stretching method, in addition to a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, and the like, a deep drawing method, a vacuum forming method, or the like having a high stretching ratio 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 stretching temperature is selected from the range of about 80 to 170 ° C, preferably about 100 to 160 ° C.

  Thus, after stretching is completed, heat setting is then performed. The heat setting can be carried out by a known means, and the heat treatment is performed at 80 to 170 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds while keeping the stretched film in a tension state. Moreover, the stretched film obtained is subjected to cooling treatment, rolling treatment, printing treatment, dry laminating treatment, solution or melt coating treatment, bag making processing, depth sticking processing, box processing, tube processing, split processing, etc. Can do.

  The multilayer structure obtained in this way has a stable gas barrier property after stretching, and can be placed in any part of the multilayer structure in the flow direction, that is, when comparing the central part and end part of the multilayer structure, Similarly, a multilayer structure having good gas barrier properties can be obtained, and it is useful as various packaging materials such as foods, pharmaceuticals, industrial chemicals and agricultural chemicals.

  Hereinafter, the method of the present invention will be specifically described with reference to examples. In the following, “%” means a weight basis unless otherwise specified.

Polymerization example 1
An EVOH composition (A1) was obtained by the following method.
A 1 m ³ polymerization can with a cooling coil is charged with 500 kg of vinyl acetate, 35 kg of methanol, 500 ppm of acetyl peroxide (vs. vinyl acetate), 20 ppm of citric acid, and 14 kg of 3,4-diacetoxy-1-butene, and the system is nitrogen After substituting once with gas, then substituting with ethylene, injecting until the ethylene pressure reaches 45 kg / cm ² , stirring, and then raising the temperature to 67 ° C., and 3,4-diacetoxy-1-butene Polymerization was carried out while adding a total amount of 4.5 kg at 15 g / min, and polymerization was carried out for 6 hours until the polymerization rate reached 50%. Thereafter, the polymerization reaction was stopped to obtain an ethylene-vinyl acetate copolymer having an ethylene content of 38 mol%.

A methanol solution of the ethylene-vinyl acetate copolymer was supplied at a rate of 10 kg / hour from the top of the plate tower (saponification tower), and at the same time 0.012% of the remaining acetic acid groups in the copolymer. A methanol solution containing an equivalent amount of sodium hydroxide was fed from the top of the tower. On the other hand, methanol was supplied at 15 kg / hour from the bottom of the tower. The tower temperature was 100 to 110 ° C., and the tower pressure was 3 kg / cm ² G. From 30 minutes after the start of charging, a methanol solution of EVOH (A1) having a structural unit having a 1,2-glycol bond (EVOH (A1) 30%, methanol 70%) was taken out. The saponification degree of the vinyl acetate component of EVOH (A1) was 99.5 mol%.

  Subsequently, the obtained methanol solution of EVOH (A1) was supplied at a rate of 10 kg / hour from the top of the methanol / water solution adjusting tower, 120 ° C. methanol vapor at a rate of 4 kg / hour, and water vapor at a rate of 2.5 kg / hour. Charge from the bottom of the column and distill methanol from the top of the column at 8 kg / hr. At the same time, 6 equivalents of methyl acetate with respect to the amount of sodium hydroxide used in the saponification is charged from the middle of the column at 95-110 ° C. Thus, a water / alcohol solution (resin concentration 35%) of EVOH (A1) was obtained from the bottom of the tower.

The obtained water / alcohol solution of EVOH (A1) was extruded in a strand form from a nozzle with a pore diameter of 4 mm into a coagulation liquid tank maintained at 5 ° C. composed of 5% methanol and 95% water. The material was cut with a cutter to obtain a porous pellet of EVOH (A1) having a diameter of 3.8 mm and a length of 4 mm and a moisture content of 45%.
After washing with 100 parts of water with respect to 100 parts of the porous pellets, the mixture was put into a mixed solution containing 0.032% boric acid and 0.007% calcium dihydrogen phosphate, and at 30 ° C. for 5 hours. Stir. Further, the porous pellets were dried for 12 hours by passing nitrogen gas having a temperature of 70 ° C. and a moisture content of 0.6% in a batch-type ventilated box dryer, and the moisture content was adjusted to 30%. Using a batch tower type fluidized bed dryer, drying was performed with nitrogen gas having a temperature of 120 ° C. and a water content of 0.5% for 12 hours to obtain pellets of the target EVOH composition (A1). Such pellets contain 0.015 parts by weight (in terms of boron) and 0.005 parts by weight (in terms of phosphate radicals) of boric acid and calcium dihydrogen phosphate with respect to 100 parts by weight of EVOH (A1). 210 ° C. 2160 g) was 4.0 g / 10 min.

The amount of 1,2-glycol bond introduced was calculated by measuring the ethylene-vinyl acetate copolymer before saponification with ¹ H-NMR (internal standard substance: tetramethylsilane, solvent: d6-DMSO). However, it was 2.5 mol%. In addition, “AVANCE DPX400” manufactured by Nippon Bruker Co., Ltd. was used for NMR measurement.

[ ¹ H-NMR] (see FIG. 1)
1.0 to 1.8 ppm: methylene proton (integrated value a in FIG. 1)
1.87 to 2.06 ppm: methyl proton 3.95 to 4.3 ppm: proton on the methylene side of structure (I) + unreacted 3,4-diacetoxy-1-butene proton (integral value b in FIG. 1) )
4.6 to 5.1 ppm: methine proton + proton on the methine side of structure (I) (integral value c in FIG. 1)
5.2 to 5.9 ppm: unreacted 3,4-diacetoxy-1-butene proton (integral value d in FIG. 1)

[Calculation method]
Since there are four protons in 5.2 to 5.9 ppm, the integral value of one proton is d / 4, and the integral value b is an integral value including the protons of the diol and the monomer. The integral value (A) of the proton is A = (b−d / 2) / 2, and the integral value c is an integral value including the protons on the vinyl acetate side and the diol side. Since the integral value (B) is B = 1− (b−d / 2) / 2 and the integral value a is an integral value including ethylene and methylene, the integral value (C) of one proton of ethylene is , C = (a−2 × A−2 × B) / 4 = (a−2) / 4, and the introduction amount of the structural unit (1) is 100 × {A / (A + B + C)} = 100 × Calculated from (2 × b−d) / (a + 2).

Polymerization example 2
An EVOH composition (A2) was obtained by the following method.
In Polymerization Example 1, the amount of methanol initially charged was 20 kg, and 210 ppm of t-butylperoxyneodecanoate (with respect to vinyl acetate) was added over 5 hours instead of acetyl peroxide, and 3,4-diacetoxy-1 -Polymerization while adding 4.5 kg in total of butene at 15 g / min, and carrying out in the same manner except that no boric acid was added. The ethylene content was 38 mol%, and a structural unit having a 1,2-glycol bond An EVOH composition (A2) having an introduction amount of 2.5 mol%, containing 0.005 parts by weight of calcium dihydrogen phosphate (in terms of phosphate radical) and having an MFR of 5.2 g / 10 min was obtained.

Polymerization example 3
An EVOH composition (A3) was obtained by the following method.
70 of 3,4-diacetoxy-1-butene, 3-acetoxy-4-ol-1-butene and 1,4-diacetoxy-1-butene instead of 3,4-diacetoxy-1-butene in polymerization example 1: The procedure is the same except that a 20:10 mixture was used. The ethylene content was 38 mol%, the introduction amount of structural units having 1,2-glycol bonds was 2.0 mol%, the ethylene content 38 mol%, boron An EVOH composition (A3) having an acid content of 0.015 part by weight (in terms of boron), 0.005 part by weight of calcium dihydrogen phosphate (in terms of phosphate group), and MFR of 3.7 g / 10 min was obtained.

Polymerization example 4
An EVOH composition (A4) was obtained by the following method.
The same procedure as in Polymerization Example 1 was conducted except that the amount of methanol charged was 100 kg and the ethylene pressure was 35 kg / cm ^{2. The} ethylene content was 29 mol% and the amount of structural units having 1,2-glycol bonds introduced was 2.5. EVOH composition (A4) containing 0.015 parts by weight of boric acid (in terms of boron), 0.005 parts by weight of calcium dihydrogen phosphate (in terms of phosphate groups), and MFR of 3.5 g / 10 min. Got.

Polymerization example 5
An EVOH composition (A5) was obtained by the following method.
A polymerization reaction was carried out under the same conditions as in Polymerization Example 1 to obtain an ethylene-vinyl acetate copolymer having an ethylene content of 38 mol%. A methanol solution of the ethylene-vinyl acetate copolymer was supplied at a rate of 7 kg / hour from the top of the plate tower (saponification tower), and at the same time, 0.008 to the remaining acetate groups in the copolymer. A methanol solution containing an equivalent amount of sodium hydroxide was fed from the top of the tower. On the other hand, methanol was supplied at 15 kg / hour from the bottom of the tower. The tower temperature was 100 to 110 ° C., and the tower pressure was 3 kg / cm ² G. From 30 minutes after the start of charging, a methanol solution of EVOH (A5) containing a structural unit having a 1,2-glycol bond (EVOH (A5) 30%, methanol 70%) was taken out. The saponification degree of the vinyl acetate component of EVOH (A5) was 98.0 mol%. Subsequent operations were carried out in the same manner as in Example 1. The amount of structural units having a 1,2-glycol bond in the side chain was 2.5 mol%, MFR was 3.7 g / 10 min, boric acid was 0.015. A pellet of EVOH composition (A5) containing parts by weight (in terms of boron) and 0.007 parts by weight of calcium dihydrogen phosphate (in terms of phosphate group) was obtained. From the ¹ H-NMR measurement of this EVOH composition (A5), all remaining acetyl groups in the unsaponified portion are based on vinyl acetate monomer, and are based on 3,4-diacetoxy-1-butene. Was confirmed not to exist.

Separately, ethylene content 3 2 mol%, saponification degree 9 9. 5 mol%, M F R = 3. 5 g / min (2 10 ° C., 2 1 60 g), boric acid content (in terms of boron) 0. 0 1 5 parts by weight, phosphoric acid 0. E V O H composition (B 1) containing 0.55 parts by weight (converted to phosphate group), ethylene content 3 2 mol%, saponification degree 9 9. 5 mol%, M F R = 3. 1 g / min (2 1O 0 C, 2 1 60 g), no boric acid added , phosphoric acid 0. E V O H composition (B 2) containing 0.55 parts by weight (converted to phosphate group), ethylene content 44 mol%, saponification degree 96 mol%, M F R = 8. 0 g / min (2 1O 0 C, 2 1 60 g), no boric acid added, phosphoric acid 0. An E V O H composition (B 3) containing 0 5 parts by weight (in terms of phosphate radical) was prepared.

Example 1
The EVOH composition (A1) and EVOH composition (B1) obtained above are supplied to a single screw extruder so that the blending weight ratio is 30:70, and melt-mixed at 220 ° C. to obtain the EVOH composition of the present invention. A product pellet was obtained.
The pellet was measured by ¹ H-NMR (internal standard substance: tetramethylsilane, solvent: d6-DMSO), and the average value of the ethylene content and the average value of the introduction amount of the structural unit (1) were calculated. The average value of the ethylene content was 33.6 mol%, and the average value of the introduction amount of the structural unit (1) was 0.9 mol%. In addition, “AVANCE DPX400” manufactured by Nippon Bruker Co., Ltd. was used for NMR measurement.

[ ¹ H-NMR] (see FIG. 2)
1.0 to 1.75 ppm: methylene proton (integrated value e in FIG. 2)
1.75 to 1.90 ppm: methine proton in the main chain of structure (1) (integrated value f in FIG. 2)
1.90 to 2.02 ppm: methyl proton of unsaponified vinyl acetate (integral value g in FIG. 2)
3.25 to 3.95 ppm: 1,2-glycol methine proton + 1,2-glycol methylene proton + vinyl alcohol methine proton (integral value h in FIG. 2)

[Calculation method]
The average value of ethylene content was calculated from 100 × (3e + 12f−2g−6h) / (3e−12f + 2g + 6h), and the introduction amount of structural unit (1) was calculated from 100 × 12f / (3e−12f + 2g + 6h).

  The pellets (EVOH composition) obtained above are supplied to a multilayer extrusion apparatus equipped with a multilayer T die of 3 types and 5 layers of feed blocks, and a polypropylene ("Novatec PP LF6H" manufactured by Nippon Polypro Co.) layer / adhesive resin ( Multi-layer film (multi-layer structure) (layer thickness 90/20/40/20/90 μm) of “Modic AP P513V”) / EVOH composition layer / adhesive resin layer (same as left) / polypropylene layer (same as left) manufactured by Mitsubishi Chemical Corporation Body). The lip width of the T die was 400 mm, and the distance from the lip to the cast roll was 16 mm. Moreover, the film forming speed at this time was 80 m / min.

(Non-neck-in)
In the production of the above-mentioned multilayer film (multilayer structure), the width of the lip of the die and the width of the obtained film were measured to obtain the difference, and the difference was determined as the neck-in amount and evaluated as follows.
○ ・ ・ ・ less than 20mm △ ・ ・ ・ 20mm or more, less than 40mm × ・ ・ ・ over 40mm

(Extensible)
The multilayer film (multilayer structure) obtained above was longitudinally stretched 3 times by a roll stretching machine at 120 ° C., further stretched 5.5 times by a tenter stretching machine in an atmosphere of 140 ° C., and subsequently 150 ° C. The obtained multilayer structure was visually observed and evaluated as follows.
○: Whitening and streaks are not observed in the multi-layer stretched film, and are uniformly stretched. Δ ... Whitening and streaks are observed in part of the end of the multi-layer stretched film. Whitening and streaks are observed on the entire surface

(Gas barrier stability)
The oxygen permeability (cc / m ² · day · atm) from end to end with a uniform spacing in the TD direction (direction perpendicular to the winding direction) of the multilayer stretched film was measured at a temperature of 23 ° C. and a humidity of 80 Measurement was performed using an oxygen permeability measuring device (“OXTRAN 10/50” manufactured by MOCON) under the condition of% RH, and the standard deviation of the measurement result was calculated. The average value of oxygen permeability was also calculated at the same time.

Example 2
In Example 1, an EVOH composition was prepared in the same manner except that the weight ratio of EVOH composition (A1) / EVOH composition (B1) was 60/40, and evaluation was performed in the same manner. The average ethylene content of the EVOH composition was 35.2 mol%, and the amount of structural unit (1) introduced was 1.5 mol%.

Example 3
In Example 1, EVOH composition (A2) was used instead of EVOH composition (A1), and EVOH composition (B2) was used instead of EVOH composition (B1). A similar evaluation was made. The average ethylene content of the EVOH composition was 33.6 mol%, and the amount of structural unit (1) introduced was 0.9 mol%.

Example 4
In Example 1, an EVOH composition was prepared in the same manner except that the EVOH composition (A3) was used instead of the EVOH composition (A1), and the same evaluation was performed.
The average ethylene content of the EVOH composition was 33.6 mol%, and the amount of structural unit (1) introduced was 0.7 mol%.

Example 5
In Example 1, an EVOH composition was prepared in the same manner except that the EVOH composition (A4) was used instead of the EVOH composition (B1), and the same evaluation was performed.
The average ethylene content of the EVOH composition was 31.5 mol%, and the amount of structural unit (1) introduced was 2.5 mol%.

Example 6
In Example 1, EVOH composition (A5) was used instead of EVOH composition (A1), and the melt mixing ratio of EVOH composition (A5) and EVOH composition (B1) was set to 20/80. An EVOH composition was prepared and evaluated in the same manner. The average ethylene content of the EVOH composition was 33.1 mol%, and the amount of structural unit (1) introduced was 0.7 mol%.

Comparative Example 1
In Example 1, evaluation was similarly performed using only the EVOH composition (B1) without using the EVOH composition (A1).

Comparative Example 2
In Example 1, EVOH (B3) was used in place of the EVOH composition (A1), and the EVOH composition was obtained by setting the EVOH composition (B1) / EVOH composition (B3) to a weight ratio of 70/30. Evaluation was performed in the same manner.

  The evaluation results of Examples and Comparative Examples are summarized in Table 1.

＊：測定上限を超えたため測定不可 [Table 1]

*: Measurement is not possible because the measurement upper limit has been exceeded.

  The EVOH composition of the present invention is excellent in non-neck-in property and stretchability. Furthermore, the multilayer structure comprising this composition as at least one layer has stable gas barrier performance and is useful as a packaging material for foods and medical products. It is.

2 is a ¹ H-NMR chart before saponification of EVOH obtained in Polymerization Example 1. FIG. 2 is a ¹ H-NMR chart of EVOH obtained in Example 1. FIG.

Claims (15)

It contains two or more different ethylene-vinyl alcohol copolymers, and at least one of them has an ethylene content of 20 to 60 mol% and contains the following structural unit (1) An ethylene-vinyl alcohol copolymer composition.

(Here, X is an alkylene group having 5 or less carbon atoms , R1 to R4 are each independently either a hydrogen atom or an alkyl group , and n represents 0 or 1.)   The ethylene-vinyl alcohol copolymer (B) different from the ethylene-vinyl alcohol copolymer (A) having the structural unit (1) has a different ethylene content or a different structural unit. The ethylene-vinyl alcohol copolymer composition according to claim 1.   The difference in ethylene content between the ethylene-vinyl alcohol copolymer (A) having the structural unit (1) and a different ethylene-vinyl alcohol copolymer (B) is 1 mol% or more. The ethylene-vinyl alcohol copolymer composition according to claim 2. 3. The ethylene-vinyl alcohol copolymer composition according to claim 2, wherein the ethylene-vinyl alcohol copolymer (B) is an ethylene-vinyl alcohol copolymer comprising only an ethylene structural unit and a vinyl alcohol structural unit. object.   The content ratio of the ethylene-vinyl alcohol copolymer (A) to the ethylene-vinyl alcohol copolymer (B) is 0. The ethylene-vinyl alcohol copolymer composition according to any one of claims 1 to 4, wherein the composition is 0 5 to 2 0 0. Ethylene of claims 1 to 5, wherein any one, characterized in that n in the structural unit (1) is 0 - vinyl alcohol copolymer composition. The ethylene-vinyl alcohol copolymer according to any one of claims 1 to 6, wherein the structural unit (1) is introduced into the molecular chain of the ethylene-vinyl alcohol copolymer (A) by copolymerization. Combined composition. The content of the structural unit (1) is 0. 0 with respect to all the ethylene-vinyl alcohol copolymer components. 1-3 0 mol% ethylene according to any one of claims 1 to 7, characterized in that - vinyl alcohol copolymer composition. The ethylene-vinyl alcohol copolymer (A) containing the structural unit (1) is obtained by saponifying a copolymer of 3,4-diasiloxy-1-butene, a vinyl ester monomer and ethylene. The ethylene-vinyl alcohol copolymer composition according to any one of claims 1 to 8 . The ethylene-vinyl alcohol copolymer (A) containing the structural unit (1) is obtained by saponifying a copolymer of 3,4-diacetoxy-1-butene, a vinyl ester monomer and ethylene. The ethylene-vinyl alcohol copolymer composition according to any one of claims 1 to 9 . Furthermore, the boron compound contains, The ethylene-vinyl alcohol copolymer composition in any one of Claims 1-10 characterized by the above-mentioned. The content of the boron compound is 0.00 on a boron basis with respect to 100 parts by weight of the total ethylene-vinyl alcohol copolymer in the composition. The ethylene-vinyl alcohol copolymer composition according to any one of claims 1 to 11, wherein the content is from 0 0 1 to 1 part by weight. Claims 1 to 1 2 ethylene according any - multilayer structure, characterized in that it comprises at least one layer of a vinyl alcohol copolymer composition. 14. The multilayer structure according to claim 13 , wherein a layer of the ethylene-vinyl alcohol copolymer composition is used as an intermediate layer, and a polyolefin resin layer is disposed on both outer layers. The multilayer structure according to claim 13 or 14 , wherein the multilayer structure is stretched 3 times or more in at least one direction.

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