JP2005041993A - Composition of saponified product of ethylene-vinyl acetate copolymer and application thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition of a saponified product of an ethylene-vinyl acetate copolymer, providing a heat-sealed part having excellent impact resistance, transparency and gas-barrier properties when formed into a film and heat-sealed. <P>SOLUTION: The composition of the saponified product of the ethylene-vinyl acetate copolymer contains two kinds of the ethylene-vinyl acetate copolymers at least one of which satisfies the formula (1): 14,750×Mw<SP>-0.75</SP>≤ECD (wherein, ECD is the standard deviation of the distribution of an ethylene component when the reacetylated product of the saponified product of the ethylene-vinyl acetate copolymer is measured by a liquid chromatography having an evaporation type light scattering detector; and Mw is a weight average molecular weight of the reacetylated product of the saponified product of the ethylene-vinyl acetate copolymer, measured by a GPC by using tetrahydrofuran as a solvent and a polystyrene as a standard). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) and its use. More specifically, the impact resistance of a heat seal portion is excellent, and transparency and gas barrier properties are also excellent. The present invention relates to an EVOH composition and a laminate using the composition.

  In general, EVOH is excellent in gas barrier properties, scent retention, solvent resistance, oil resistance, etc., making use of such properties, various packaging materials such as food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, agricultural chemical packaging materials, etc. It is used for.

  And in such packaging material applications, when the contents are packed into a container such as a pouch or cup and circulated as a product, the packaging material is damaged by dropping or impact during transportation, and the value of the product is increased. It may be damaged. In particular, the heat seal part of the container is often subjected to an impact and cracks are often generated, and the impact resistance strength of such a heat seal part is important. The safety of goods has become particularly important, and accordingly, the transparency of packaging materials has also become important so that consumers can fully visually confirm the contents.

In order to improve such heat sealability, two types of EVOH having different melt viscosity behaviors are blended (for example, see Patent Documents 1 and 2), or an ethylene-vinyl acetate copolymer having a specific saponification gradient in EVOH. It has been proposed to blend a saponified polymer (for example, see Patent Document 3).
JP-A-3-112653 JP-A-3-112654 JP-A-6-145441

  However, the EVOH blends described in Patent Documents 1 and 2 are excellent in heat sealability and impact resistance at low temperatures, but are found to be less transparent because EVOH is incompatible with each other. did. Moreover, although the EVOH blend described in Patent Document 3 is excellent in heat sealability and transparency, there is a risk that the gas barrier property is lowered due to a low saponification degree component, and the heat seal portion has a resistance to heat seal. An EVOH composition that is excellent in impact properties and excellent in transparency and gas barrier properties is desired.

Therefore, paying attention to the structure of any EVOH used in EVOH blends, especially the distribution of ethylene content in EVOH, the ethylene distribution of conventional EVOH is relatively sharp and the polymerization average molecular weight is large. From the recognition that the tendency is higher, the improvement of the above-mentioned conventional EVOH blend is more effective in improving the ethylene distribution of EVOH, and even if the average molecular weight is higher than the conventional product. In addition, the inventors have obtained the knowledge that an improvement effect can be expected if this distribution can be maintained in a broad state, and as a result of further earnest research, as a result of containing two EVOH species, at least one of them contains the following (1 The present invention has been completed by finding that a composition satisfying the above formula meets the above-mentioned purpose.
14750 × Mw ^−0.75 ≦ ECD (1)

  Here, ECD is a standard deviation of ethylene composition distribution when re-acetylated ethylene-vinyl acetate copolymer saponified product is measured by liquid chromatography equipped with an evaporative light scattering detector, Mw is tetrahydrofuran as a solvent, It is the weight average molecular weight of the re-acetylated product of the saponified ethylene-vinyl acetate copolymer measured by GPC using polystyrene as a standard.

  Since the EVOH composition of the present invention is blended with EVOH having a specific ethylene distribution, it has excellent impact resistance at the heat-sealed part when molded into a film or the like and heat-sealed, and has transparency and gas barrier. Excellent in properties and can be molded into containers made of cups, trays, tubes, etc., bags and lids made of stretched films, and various packaging for food, beverages, pharmaceuticals, cosmetics, industrial chemicals, detergents, agricultural chemicals, fuels, etc. Useful as a material.

The present invention is described in detail below.
At least one EVOH of the two types of EVOH used in the present invention satisfies the following formula (1).
14750 × Mw ^−0.75 ≦ ECD (1)
Here, ECD is the standard deviation of ethylene composition distribution when EVOH reacetylated product is measured by liquid chromatography equipped with an evaporative light scattering detector, Mw is GPC using tetrahydrofuran as a solvent and polystyrene as a standard. It is the weight average molecular weight of the re-acetylated product of EVOH measured in (1).

There is no conventional commercially available EVOH that satisfies this relational expression, and it cannot be used for the purpose of the present invention.
In the present invention, it is further preferable that 14850 × Mw ^−0.75 ≦ ECD, more preferably 15000 × Mw ^−0.75 ≦ ECD, within the range of the above formula (1).
The upper limit of the ECD is not particularly limited, but theoretically, 29.2 is the upper limit value. This shows a standard deviation when the ethylene composition is uniformly distributed in 0 to 100 mol%.

  In order to obtain EVOH satisfying the above formula (1), the production method is not particularly limited, but the polymerization conditions are set at the initial stage of polymerization of the ethylene-vinyl acetate copolymer, and then the polymerization is simply performed. When the polymerization rate is continued, the polymerization rate is preferably 60 to 95% (particularly preferably 65 to 93%, more preferably 70 to 90%). If EVOH cannot be obtained and the polymerization rate exceeds 95%, the target EVOH can be obtained, but this is not preferable because it takes a long time for the polymerization.

It is also a preferred method to continuously change the polymerization conditions over time during the polymerization of the ethylene-vinyl acetate copolymer.
Methods for changing the polymerization conditions over time include 1) a method of changing the polymerization temperature over time, 2) a method of changing the pressure over time, and 3) changing the monomer and solvent composition (S / M) over time. The rate of change is not only linearly changed but also quadratic, cubic, multidimensional, and exponential with respect to time. It may be changed logarithmically.

The above method will be described in more detail.
1) A method of changing the polymerization temperature over time.
In changing the polymerization temperature, the temperature may be changed from a low temperature to a high temperature, and conversely, the temperature may be changed from a high temperature to a low temperature. However, in the latter case, the amount of cleavage of the catalyst decreases, the solution viscosity increases and the reactivity increases. The former method is preferable because it worsens. In this case, the initial temperature is preferably 30 to 60 ° C. (more preferably 35 to 58 ° C., particularly 40 to 55 ° C.). If the initial temperature is less than 30 ° C., the polymerization rate is low and the yield is low. On the other hand, if it exceeds 60 ° C., the temperature variable range becomes narrow and it becomes difficult to obtain the target EVOH. The final temperature at the end of the polymerization is preferably from 50 to 90 ° C. (more preferably from 55 to 88 ° C., particularly from 60 to 85 ° C.). It becomes difficult to obtain EVOH. On the other hand, when the temperature exceeds 90 ° C., the cleavage of the catalyst becomes severe, which is not practical and not preferable. The rate of temperature rise from the initial temperature to the final temperature is preferably 0.7 to 30 ° C./hr (more preferably 0.8 to 28 ° C./hr, particularly 1 to 25 ° C./hr). When it is less than 7 ° C./hr, the reaction time becomes long, and when it exceeds 30 ° C./hr, the degree of polymerization is lowered, which is not preferable.

For example, when the temperature is changed linearly, if the polymerization temperature t minutes after the start of polymerization is T (t), it can be performed under conditions that satisfy the following expressions (2) and (3). .
T (t) = T _S + k _T t (2)
T (t) ≦ _TF (3)
Here, k _T is a temperature raising / lowering rate (° C./hr), and the range of k _T has an absolute value of 0.7 ≦ k _T ≦ 30. k _T is the time of the negative value means that the lower the temperature. Ts is a polymerization start temperature (° C.), and T _F is a polymerization end temperature (° C.). In the case of T _S <T (t), 30 ≦ T _S ≦ 60 (° C.), and in the case of T _S > T (t), 50 ≦ T _S ≦ 90 (° C.). In the case of T _S <T (t), T _S is further preferably 35 to 58 ° C., particularly preferably 40 to 55 ° C. If T _S is less than 30 ° C., the polymerization rate is low, and the yield is low. If it exceeds 60 ° C., the temperature variable range becomes narrow, which is not preferable. In the case of T _S > T (t), T _S is further preferably 55 to 88 ° C., particularly preferably 60 to 85 ° C. If the temperature is less than 50 ° C., the temperature variable range becomes narrower, and conversely exceeds 90 ° C. Then, the cleavage of the catalyst becomes severe, which is not preferable.

Regarding T _F , when T _S <T (t), T _F is preferably 50 to 90 ° C. (more preferably 55 to 88 ° C., particularly 60 to 85 ° C.), and the temperature is less than 50 ° C. If the variable range becomes narrow, and if it exceeds 90 ° C, the cleavage of the catalyst becomes severe, which is not preferable. In the case of T _S > T (t), T _F is preferably 30 to 60 ° C. (more preferably 35 to 58 ° C., particularly 40 to 55 ° C.). On the other hand, if the temperature drops below 60 ° C., the temperature variable range becomes narrow, which is not preferable.

Also, k _T in the range of absolute value _{0.7 ≦ k T ≦ 30 ℃ /} hr ( more _{0.8 ≦ k T ≦ 28 ℃ /} hr, especially _{1 ≦ k T ≦ 25 ℃ /} hr) is preferably When the absolute value of k _T is less than 0.7 ° C./hr, the reaction time is long, and conversely, when it exceeds 30 ° C./hr, a polymer having a sufficient degree of polymerization cannot be obtained. When k _T is a negative value, it means that the temperature is lowered.

Next, when the temperature is changed in a quadratic function, a cubic function, an exponential function, or a logarithmic function, the temperature at the time t may be controlled as shown in the following equation (4).
T (t) = Ts + a _{T, 1} t + a _{T, 2} t ² +... + A _{T, n} t ⁿ (4)
Here, a _{T, 1} to a _{T, n} are arbitrary constants and are determined by a change in T (t) with respect to time.
At this time, the range of T _S and T _F may be the same as when the polymerization temperature is changed linearly. Further, the temperature raising / lowering speed may be as long as the absolute value of the differential coefficient T ′ (t) of the equation (4) at the time t is the same as the absolute value range of k _T.
When the polymerization temperature is raised, the yield is low at low temperatures, so it is preferable to slow the rate of temperature rise on the low temperature side. In this case, it is preferable to employ an exponential function or a quadratic function temperature change with respect to time. Further, when the temperature is changed from high temperature to low temperature, it is preferable to decrease the temperature lowering rate when the temperature decreases, contrary to the above.

2) A method of changing the pressure over time.
When the pressure in the system is changed over time, it cannot be generally stated depending on the amount of ethylene to be copolymerized, but the initial pressure is 20 to 50 kg / cm ² (more preferably 22 to 48 kg / cm ² , particularly 25 ˜45 kg / cm ² ), and when the pressure is less than 20 kg / cm ^{2, the} copolymerization ratio of ethylene may be too low to obtain the desired EVOH, and conversely the pressure is If it exceeds 50 kg / cm ² , it is not preferable because the variable region of the pressure becomes narrow and the desired EVOH having an ethylene distribution may not be obtained. The final pressure is preferably 40 to 90 kg / cm ² (more preferably 42 to 88 kg / cm ² , particularly 45 to 85 kg / cm ² ). When the pressure is less than 40 kg / cm ² , In some cases, the EVOH having the target ethylene distribution cannot be obtained due to the narrower variable region of the resin, and conversely, if it exceeds 90 kg / cm ² , the copolymerization ratio of ethylene becomes too high and the target EVOH cannot be obtained. This is not preferable.

When changing the pressure, the pressure is selected in accordance with the target composition distribution. For example, when changing the ethylene pressure linearly, assuming that the ethylene pressure after t minutes of polymerization is P (t), the following (5) and (6) It is possible to carry out on the conditions which satisfy | fill a formula.
P (t) = P _S + k _P t (5)
P (t) ≦ P _F (6)
Here, k _P is a lifting pressure rate ^{(kg / cm 2 · hr)} , the range of the absolute value of k _P is _{0 · 5 ≦ k P ≦ 20} . k _P is when the negative value means reducing the pressure of ethylene. P _S is the polymerization starting ethylene pressure (kg / cm ^2), a P _F polymerization at the end of ethylene pressure (kg / cm ^2). In the case of P _S <P (t), 20 ≦ P _S ≦ 50 (kg / cm ² ), and in the case of P _S > P (t), 40 ≦ P _S ≦ 90 (kg / cm ² ). For P _S <P (t), more 22~45kg / cm ^2, particularly preferably 25~45kg / cm ² as P _S, if the P _S is less than 20 kg / cm ² low ethylene content On the other hand, if P _S exceeds 50 kg / cm ² , the pressure variable region becomes narrow, which is not preferable. If P _S> P of (t), more 42~88kg / cm ^2, particularly preferably 45~85kg / cm ² as P _S, the variable region of the pressure when the P _S is less than 40 kg / cm ² On the other hand, if the P _S exceeds 90 kg / cm ² , the composition of the produced ethylene becomes too high, which is not preferable.

Regarding P _F , when P _S <P (t), P _F is preferably 40 to 90 kg / cm ² (more preferably 42 to 88 kg / cm ² , particularly 45 to 85 kg / cm ² ), and the pressure Is less than 40 kg / cm ² , the pressure variable region becomes narrow, and conversely if it exceeds 90 kg / cm ² , the composition of produced ethylene becomes too high, which is not preferable. For _{P S> P (t),} P F is 20 to 50 kg / cm ² (more 22~45kg / cm ^2, particularly 25~45kg / cm ²⁾ is preferred, the pressure is 20 kg / cm ² less than In such a case, the ethylene composition becomes too low. On the other hand, if the pressure exceeds 50 kg / cm ² , the pressure variable region becomes narrow, which is not preferable.

The range of the absolute value of k _P is preferably 0.1 to 20 kg / cm ² · hr (more preferably 0.2 to 18 kg / cm ² · hr, particularly 0.3 to 15 kg / cm ² · hr), If the rate is less than 0.1 kg / cm ² · hr, a long time is required for the reaction. Conversely, if the rate exceeds 20 kg / cm ² · hr, the reaction time becomes longer due to a temperature drop or a reaction rate drop due to ethylene supply. Therefore, it is not preferable. When k _P is a negative value, it means that the ethylene pressure is lowered.

Next, when changing the ethylene pressure in a quadratic function, a cubic function, an exponential function, or a logarithmic function, the ethylene pressure at time t may be controlled as shown in the following equation (7).
P (t) = Ps + a _{P, 1} t + a _{P, 2} t ² +... + A _{P, n} t ⁿ (7)
It is represented by Here, a _{P, 1} to a _{P, n} are arbitrary constants and are determined by the change of P (t) with respect to time.
In this case, the range of P _S and P _F is the same as the case of changing the linear polymerization temperature. Further, the pressure increase / decrease rate of the ethylene pressure may be as long as the absolute value of the differential coefficient P ′ (t) in the equation (7) at the time t is the same as the range of the absolute value of k _P.

  When changing from high pressure to low pressure, it is necessary to provide equipment for preventing entrainment, so it is preferable to change from low pressure to high pressure.

3) Method of changing the ratio (S / M) of vinyl acetate monomer and solvent over time When changing the composition ratio (S / M) of vinyl acetate monomer and solvent, the composition ratio of vinyl acetate monomer and solvent is the target. Although it is selected according to the composition distribution, in this method, the composition ratio of the vinyl acetate monomer or the solvent during polymerization can be changed over time by dropping the vinyl acetate monomer or the solvent during the polymerization process.

For example, when adding vinyl acetate monomer or solvent linearly (quantitatively), the total amount of vinyl acetate monomer or solvent added at time t may be added so as to satisfy the following equation (8).
S (t) = S _S + k _s t (8)
Here, S _S is the amount (g) of vinyl acetate monomer or solvent at the start of polymerization, and k _s is the dropping rate (g / hr) of the vinyl acetate monomer or solvent. However, the range of S _S may if 0 or more, but the upper limit is not particularly limited is limited by the size of the reactor. When the total amount of vinyl acetate monomer and solvent that can be charged into the reaction vessel is T _s (g), the range of k _S is Ts / 500 ≦ k _s ≦ Ts / 10 (g / hr), preferably Ts / 300. ≦ k _s ≦ Ts / 30 (g / hr), more preferably Ts / 200 ≦ k _s ≦ Ts / 50 (g / hr), and the drop rate is less than Ts / 500 (g / hr). On the contrary, if Ts / 10 (g / hr) is exceeded, reaction control becomes difficult, which is not preferable.

Next, when the total dripping amount of the vinyl acetate monomer or the solvent is changed in a quadratic function, a cubic function, an exponential function, or a logarithmic function, the dripping total amount at time t is controlled as shown in the following equation (9). That's fine.
S (t) = S _S + a _{S, 1} t + a _{S, 2} t ² +... + A _{S, n} t ⁿ (9)
Here, a _{S, 1} to a _{S, n} are arbitrary constants and are determined by the change of S (t) with respect to time.
Also in this case, the S _S range is the same as when the total amount of the vinyl acetate monomer or the solvent dropped is changed linearly. Further, the dropping rate of the vinyl acetate monomer or the solvent may be such that the value of the derivative S ′ (t) in the equation (9) at the time t is the same as the range of k _S.

In the present invention, the polymerization can be carried out by arbitrarily combining the above methods 1) to 3), and in particular, the methods 1) and 2) can be combined to change the temperature and pressure during the polymerization. Polymerization is also a preferred embodiment.
The polymerization is not particularly limited and can be performed by methods such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc., but saponification of the ethylene-vinyl acetate copolymer in the subsequent step Solution polymerization is preferred in view of process productivity.

  In the polymerization described above, a polymerization initiator is used. Such a polymerization initiator is not particularly limited as long as it is a radical initiator, and preferably 2,2'-azobis- (2,4-dimethylvaleronitrile). 2,2'-azobis- (2,4,4-trimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis- (4-methoxy-2,4-dimethylvalero) Nitrile), azo compounds such as dimethyl 2,2'-azobisisobutyrate, t-butylperoxyneodecanoate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, α, α′bis (neodecanoylperoxy) diisopropyl 1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methyl ester Peroxyesters such as tilperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyisobutyrate, t-hexylperoxypivalate, di-n-butylperoxydicarbonate Bis- (4-t-butylcyclohexyl) peroxydicarbonate, dicyclohexylperoxydicarbonate, bis (2-ethylhexyl) di-sec-butylperoxydicarbonate, di-n-propylperoxydicarbonate, di- iso-propyl peroxydicarbonate, di-sec-butylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di (2-ethylhexyl) per Oxydicarbo Peroxydicarbonates such as dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate, dibenzoyl peroxide, distearoyl peroxide, dilauroyl peroxide, diocta Diacyl peroxides such as noyl peroxide, didecanoyl peroxide, 3,3,5-trimethylhexanoyl peroxide, diisobutyryl peroxide, dipropyl peroxide, and diacetyl peroxide are used.

The ethylene-vinyl acetate copolymer thus obtained is then saponified. Such saponification is necessary with, for example, a homogeneous system in an alcohol solvent such as methanol, or an alcohol such as methanol or ethanol. In a heterogeneous system in a mixed solvent to which water is added according to the conditions, saponification is carried out using an alkali metal compound such as sodium or potassium hydroxide or an alkoxide or an acid catalyst such as hydrochloric acid, sulfuric acid or acetic acid as a saponification catalyst. .
In the case of heterogeneous saponification, acetone, hydrazine, long-chain alkylamines and the like may be added as necessary to prevent coloring.

  Thus, EVOH used for the purpose can be obtained and used as it is for the EVOH blend (composition). Usually, the EVOH obtained by the above saponification is formed into pellets and then used in the present invention. Often used as a blend.

  In forming such a pellet, a known method can be employed. For example, a strand or sheet obtained after extruding a mixed solution of EVOH water and alcohol into a coagulating liquid into a strand or a sheet is obtained. Can be cut into pellets. As the shape of the pellet-like EVOH, a cylindrical shape, a spherical shape or the like is preferable. In the case of a cylindrical shape, the diameter is preferably 1 to 10 mm and the length is preferably 1 to 10 mm. In the case of a spherical shape, the diameter is 1 to 10 mm. preferable.

  Such EVOH may contain an alkali metal, an alkaline earth metal, boric acid, phosphoric acid or the like for the purpose of imparting thermal stability and adhesiveness. In that case, those having a microporous internal structure in which pores having a diameter of about 0.1 to 10 μm are uniformly distributed are preferable in that such substances can be contained uniformly, and usually a solution of EVOH (water / alcohol). When extruding a mixed solvent or the like) into a coagulation bath, the concentration of EVOH solution (20 to 80% by weight), the extrusion temperature (45 to 70 ° C.), the type of solvent (water / alcohol mixing weight ratio = 80/20 to 5) / 95 etc.), the temperature of the coagulation bath (1 to 20 ° C.), the residence time (0.25 to 30 hours), the EVOH amount in the coagulation bath (0.02 to 2% by weight), etc. are arbitrarily adjusted. Thus, EVOH having the structure can be obtained. Furthermore, those having a water content of 20 to 80% by weight are preferable because they can uniformly and rapidly contain the above-mentioned compounds and the like. In addition, the adjustment of the content of the substance is not particularly limited, but in the contact treatment with the aqueous solution described above, the concentration of the aqueous solution of the substance, the contact treatment time, the contact treatment temperature, the stirring frame speed during the contact treatment and the treatment are performed. This is possible by controlling the water content of EVOH. Examples of the alkali metal and alkaline earth metal include sodium, potassium, calcium, magnesium, manganese, copper, cobalt, and zinc. Among them, sodium, potassium, calcium, magnesium, and zinc are preferable. Further, it can be contained as a metal salt of a fatty acid such as acetic acid or stearic acid, or an inorganic acid such as phosphoric acid. In addition, when phosphoric acid is contained, hydrogen phosphate and phosphoric acid can be used in addition to the alkali metal or alkaline earth metal phosphate metal salt.

The pellet-shaped EVOH thus obtained is usually dried after the above contact treatment.
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.

  EVOH is dried under the above conditions. The water content of EVOH after the drying treatment is 0.001 to 5% by weight (more preferably 0.01 to 2% by weight, particularly 0.1 to 1% by weight). Part), if the water content is less than 0.001% by weight, the long-run moldability tends to be reduced. Conversely, if the water content exceeds 5% by weight, foaming occurs during extrusion molding. There is fear and it is not preferable.

EVOH has an ethylene content (average value, the same applies hereinafter) of 10 to 70 mol% (more preferably 20 to 60 mol%, particularly 25 to 55 mol%), and an average saponification degree (hereinafter the same applies) of 85 mol. % Or more (further 90 mol% or more, particularly 95 mol% or more) is preferable. If the ethylene content is less than 10 mol%, heat sealability at low temperatures may not be exhibited sufficiently, Gas barrier property and melt moldability at the time of wetness are deteriorated. On the contrary, if it exceeds 70 mol%, sufficient gas barrier property cannot be obtained, and if the saponification degree is less than 85 mol%, gas barrier property, thermal stability, moisture resistance, etc. Is not preferable.
The ethylene content can be adjusted during the production of the ethylene-vinyl acetate copolymer, and the saponification degree can be adjusted during the saponification.

Further, the melt flow rate (MFR) of EVOH (210 ° C., load 2160 g) is not particularly limited, but is 0.1 to 100 g / 10 minutes (more preferably 0.5 to 50 g / 10 minutes, particularly 1 to 30 g / 10 min) is preferable, and when the melt flow rate is smaller than this 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. Is not preferable because the appearance and gas barrier properties at the time of heat-stretching molding may be deteriorated.
In adjusting the MFR, it is only necessary to adjust the degree of polymerization of EVOH, and it is also possible to adjust by adding a crosslinking agent or a plasticizer.

  In the present invention, other copolymerizable ethylenically unsaturated monomers may be copolymerized as long as the object of the present invention is not impaired.

The EVOH composition of the present invention contains two types of EVOH, and at least one of them may be the above-mentioned EVOH, and the other EVOH is an EVOH that deviates from the condition of the above formula (1), that is, a conventionally known EVOH composition. EVOH can be used. Of course, it is also possible to use two types of EVOH that satisfy the above formula (1).
When conventionally known EVOH is used, it is not particularly limited, but the ethylene content is 20 to 70 mol% (more preferably 23 to 58 mol%, particularly 25 to 55 mol%), and the saponification degree of the vinyl acetate component is 90. Those having a mol% or more (more preferably 95 mol% or more, particularly 99 mol% or more) are preferably used. If the ethylene content is less than 20 mol%, the melt moldability is lowered. Sufficient gas barrier properties cannot be obtained, and if the saponification degree of the vinyl acetate component is less than 90 mol%, the gas barrier properties, thermal stability, moisture resistance and the like are deteriorated.

  Further, the melt flow rate (MFR) (210 ° C., load 2160 g) of the EVOH is preferably 0.5 to 100 g / 10 minutes (further 1 to 50 g / 10 minutes, particularly 3 to 35 g / 10 minutes), When the melt flow rate is less than 0.5 g / 10 min, the inside of the extruder may be in a high torque state at the time of molding, making extrusion difficult. Conversely, when it exceeds 100 g / 10 min, The thickness accuracy of the sheet may decrease, which is not preferable.

  The EVOH is obtained by saponification of an ethylene-vinyl acetate copolymer, and the ethylene-vinyl acetate copolymer is produced by any known polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization and the like. The saponification of the ethylene-vinyl acetate copolymer can also be performed by a known method.

  In addition, an ethylenically unsaturated monomer that can be copolymerized within a range not inhibiting the effect of the present invention may be copolymerized, and as such a monomer, olefins such as propylene, 1-butene, and isobutene, Unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid or salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, carbon N-alkyl acrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salt, acrylamides such as acrylamidopropyldimethylamine or its acid salt or quaternary salt thereof, methacrylamide, carbon number 1-18 N-alkylmethacrylamide, N, N-dimethylmeta N, such as rylamide, 2-methacrylamide propanesulfonic acid or its salt, methacrylamide such as methacrylamide propyldimethylamine or its acid salt or quaternary salt, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, etc. -Vinyl cyanides such as vinylamides, acrylonitrile and methacrylonitrile, vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride , Vinyl halides such as vinyl bromide, vinyl silanes such as trimethoxyvinylsilane, allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3- Acrylamide-3-dimethylpropyl) - ammonium chloride, and the like acrylamido-2-methylpropanesulfonic acid. Further, it may be post-modified such as urethanization, acetalization, cyanoethylation and the like within the range not impairing the gist of the present invention. Further, EVOH containing silicon as described in JP-A-60-144304 can also be used.

  Such EVOH can also be formed into pellets by the same method as the above-mentioned EVOH, and may also contain alkali metal, alkaline earth metal, boric acid, phosphoric acid and the like.

  Thus, two types of EVOH are selected from the EVOH as described above to obtain the EVOH composition of the present invention. In such selection, EVOH having different saponification degrees, EVOH having different ethylene contents, and different MFRs are used. EVOH, EVOH having a different ethylene distribution, etc. are not particularly limited, but in order to obtain the effects of the present invention more remarkably, it is preferable to select at least two types of EVOH having different ethylene contents. The difference in content is preferably 4 mol% or more, more preferably 5 to 40 mol%, particularly 8 to 35 mol%, especially 10 to 30 mol%. There is a risk of lowering, which is not preferable.

  In addition, the blend ratio of the two types of EVOH is not particularly limited. However, when the ratio of either one is less than 10% by weight, the blending effect may not be sufficiently exerted, and the ratio is 10% by weight, and further 20% by weight. % Or more, and particularly preferably 30% by weight or more.

  In addition, there is no particular limitation on such blending, and after dry blending each pellet, a melt kneading method using a single or twin screw extruder or the like, either one of the above two types is supplied to the extruder A method of supplying another EVOH to the melted state (solid side feed method), supplying one of the two types to the extruder and supplying the other EVOH in a molten state to the melted portion The method (melt side feed method) etc. can be mentioned, The melt-kneading method by a twin-screw extruder is especially preferable.

  Further, in the present invention, a saturated aliphatic amide (for example, stearic acid amide), unsaturated fatty acid amide (for example, oleic acid amide), bis-fatty acid amide, and the like within a range not impairing the object of the present invention to the obtained EVOH composition (E.g., ethylene bis stearamide), fatty acid metal salts (e.g., calcium stearate, magnesium stearate, etc.), low molecular weight polyolefin (e.g., low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or low molecular weight polypropylene, etc.) , 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, Aluminum added with water-absorbing substances and electrolytes, aluminum Umum powder, potassium sulfite, photocatalytic titanium oxide, etc. 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 ( Example: a combination of polypropylene and cobalt), a blend of a carbon-carbon unsaturated bond-containing resin and a transition metal (eg, a combination of polybutadiene and cobalt), a photo-oxidative decay resin (eg, polyketone), an anthraquinone polymer (example) : Polyvinyl anthraquinone), etc., and further, photoinitiators (benzophenone, etc.), peroxide supplements (commercial antioxidants, etc.) and deodorants (activated carbon, etc.) added to these compounds), heat Stabilizers, light stabilizers, antioxidants, UV absorbers, colorants, antistatic agents, surfactants, antibacterial agents, antiblocking agents, slip agents, fillers (eg inorganic fillers), other resins (eg polyolefins) , Polyamide, etc.) may be blended.

  The EVOH composition of the present invention thus obtained can be applied to various molded products. Examples of such molded products include a single-layer film containing the EVOH composition of the present invention, and at least one surface of the single-layer film. It is also preferable to use as a laminate obtained by laminating a thermoplastic resin layer on the surface, and a laminate suitable for practical use with water resistance, mechanical properties, heat sealability and the like is obtained. To do.

  In producing the laminate, another substrate (thermoplastic resin or the like) is laminated on one or both sides of the layer containing the EVOH composition of the present invention. A method of melt extrusion laminating another substrate to a film, sheet or the like containing the EVOH composition, conversely, a method of melt extrusion laminating the EVOH composition of the present invention to another substrate, the EVOH composition of the present invention and other methods A method of co-extrusion with a base material, the EVOH composition (layer) of the present invention and another base material (layer) using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester-based compound, or a polyurethane compound. Examples include a method of dry lamination. The melt molding temperature at the time of melt extrusion is often selected from the range of 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 further reducing these Polyalcohols to be used, and EVOH other than (A) and (B) can be mentioned. From the viewpoint of practicality such as physical properties (particularly strength) of the laminate, polypropylene, ethylene-propylene (block or random) A copolymer, polyamide, polyethylene, ethylene-vinyl acetate copolymer, polystyrene, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) are preferably used.

  In addition, when a substrate such as a film or sheet containing the EVOH composition of the present invention is extrusion coated with another substrate, or a film or sheet of another substrate is laminated using an adhesive, such a substrate is used. In addition to the thermoplastic resin described above, any base material (paper, metal foil, uniaxially or biaxially stretched plastic film or sheet and its inorganic deposit, woven fabric, non-woven fabric, metallic cotton, wood, etc.) is also used. Is possible.

  The layer structure of the laminate is such that the layer containing the EVOH composition of the present invention is a (a1, a2,...), And another substrate, for example, a thermoplastic resin layer is b (b1, b2,...). When the a layer is the innermost layer, not only a two-layer structure of [inner side] a / b [outer side] (hereinafter the same), but also a / b / a, a1 / a2 / b, a / Any combination of b1 / b2, a1 / b1 / a2 / b2, a1 / b1 / b2 / a2 / b2 / b1, etc. is possible, and a regrind layer comprising at least a mixture of an EVOH composition and a thermoplastic resin Is R, a / R / b, a / R / a / b, a / b / R / a / R / b, a / b / a / R / a / b, a / b / R / It is also possible to use a / R / a / R / b or the like.

  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 laminate can be obtained, and varies depending on the type of resin b. Examples thereof include modified olefin polymers containing carboxyl groups obtained by chemically bonding such as 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-ethylene Le 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, polyisobutylene, rubber / elastomer components such as 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 laminate 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 5 to 500 μm (more preferably 10 to 200 μm), b The layer is selected from the range of about 10 to 5000 μm (more preferably 30 to 1000 μm), and the adhesive resin layer is about 5 to 400 μm (more preferably 10 to 150 μm).

  The laminate is used in various shapes as it is, but it is also preferable to perform a heat stretching treatment in order to further improve the physical properties of the laminate. Here, the heat-stretching treatment is a uniform film, sheet, or parison-like laminate that is heated uniformly in a cup, tray, tube, or film by chucking, plugging, vacuum, pneumatic, or blowing. This stretching may be either uniaxial stretching or biaxial stretching, and physical properties are better when stretching as high a magnification as possible, and pinholes, cracks, stretching during stretching A stretched molded article having excellent gas barrier properties and free from unevenness, uneven thickness, delamination and the like can be obtained.

  As the stretching method, a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, a vacuum / pressure 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 60 to 170 ° C, preferably about 80 to 160 ° C. It is also preferable to perform heat setting after the completion of stretching. 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.

  In addition, when used for heat shrink packaging applications such as raw meat, processed meat, cheese, etc., after heat stretching after stretching, it is a product film, and after storing the above raw meat, processed meat, cheese, etc. in the film, The film is heat-shrinked at 50 to 130 ° C., preferably 70 to 120 ° C. for about 2 to 300 seconds, and the film is heat-shrinked for close-packaging.

  The shape of the laminate thus obtained may be any shape, and examples thereof include a film, a sheet, a tape, and a modified cross-section extrudate. In addition, the obtained laminate can be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making processing, deep drawing processing, box processing, tube processing, split processing, etc. It can be carried out.

  Containers made of cups, trays, tubes, etc. obtained as described above and bags and lids made of stretched films are useful as various packaging materials such as foods, beverages, pharmaceuticals, cosmetics, industrial chemicals, detergents, agricultural chemicals, and fuels. .

Hereinafter, the present invention will be specifically described with reference to examples.
(Measurement of molecular weight distribution)
In measuring the weight average molecular weight of EVOH, EVOH was re-acetylated and measured according to the method described in Journal of Japan Adhesion Association, 13 , 186 (1977). Further, GPC of “Waters 2690” manufactured by Waters was used, tetrahydrofuran was used as a solvent, and polystyrene was used as a standard, and detection was performed with a differential refractometer.

(Measurement of average ethylene composition and average degree of saponification)
EVOH was dissolved in deuterated dimethyl sulfoxide, and then measured by proton-NMR (“DPX-400” manufactured by Bruker) at a temperature of 50 ° C.

(Measurement of ethylene composition distribution)
Evaporative light scattering detector (ELSD) (Polymer Laboratory's “PL-ELS1000”) is attached to high performance liquid chromatography (“LC1100 system” manufactured by HEWLETT PACKARD), and EVOH reacetylated product (ethylene-vinyl acetate copolymer) ) Was measured.
The flow rate of the mobile phase at this time was 0.5 mL / min, and the eluent was performed by a gradient system using two kinds of solvents A and B. Solvent A was a solvent in which the volume ratio of acetonitrile and water was 90:10, and solvent B was tetrahydrofuran. The solvent gradient was changed linearly so that the mixing ratio of the solvent A and the solvent B was changed with time, and the solvent A was 100% at the start of measurement and the solvent A became 40% 60 minutes after the start of the measurement. The sample solution was adjusted to a sample concentration of about 1 mg / mL using solvent A as a solvent. The injection volume was 100 microliters. One C18 column (“GL-Pack Nucleosil C18-100” manufactured by GL Sciences) was used as the column. The column temperature was set to 40 ° C. The evaporative light scattering detector (ELSD) was measured at a supply gas (nitrogen gas) of 1.2 L, a nebulizer temperature of 60 ° C., and an evaporator temperature of 90 ° C.

By this procedure, liquid chromatogram data can be obtained. However, since the detection intensity in ELSD is not proportional to the concentration, it is necessary to correct the sensitivity of the detector, and the sensitivity correction was performed in the following manner.
Using at least two types of EVOH re-acetylated products having different ethylene compositions of 5 mol%, each of the solutions having a concentration of 4 (equal concentration difference) within the range of 0.1 to 1.5 mg / mL was measured, and the chromatogram Then, the correction coefficient f was obtained using the intensity obtained by cutting the baseline from the chromatogram. The correction coefficient f is obtained by dividing the intensity at each point of the chromatogram obtained by cutting the baseline from the chromatogram by a constant a, and multiplying this by 1 / f to obtain the sum for each intensity. Further, the sum of squares of values obtained by subtracting the constant c from the concentration divided by the concentration was determined so as to minimize the sum of the values obtained for the respective concentrations of each sample, and used as a correction coefficient value.
It should be noted that the constants a and c may be set to arbitrary values at the beginning of the calculation, and determined when the sum obtained by the calculation is minimized, and c may be a positive integer.

Next, a calibration curve for converting the elution time into the copolymer composition is prepared. In preparing the calibration curve, 5 samples (average ethylene composition at this time) were prepared with the average ethylene composition known by NMR measurement. The difference between the elution time and the copolymer composition is a quadratic function for the chromatogram obtained by measuring and measuring the sensitivity of the obtained raw chromatogram. As a result, the elution time was converted into the copolymer composition from the coefficient of the quadratic function when the square of the difference between the sum of the product of the intensity fraction at each point and the copolymer composition and the copolymer composition obtained by NMR was minimized. .
According to the above procedure, a differential distribution curve was obtained, and an average ethylene composition (average value of ethylene content) of EVOH reacetylated product (ethylene-vinyl acetate copolymer) and a standard deviation representing a spread of the composition distribution were obtained. .

Example 1
A 10 L polymerization can with a cooling coil was charged with 5000 g of vinyl acetate, 425 g of methanol, 460 ppm of benzoyl peroxide, and 30 ppm of citric acid. The system was temporarily replaced with nitrogen gas, and then replaced with ethylene. The mixture was pressed into cm ² and stirred well, then heated to 61 ° C. and polymerized for 10 hours until the polymerization rate reached 83%. Thereafter, the polymerization reaction was stopped to obtain an ethylene-vinyl acetate copolymer, which was saponified and then dried to obtain EVOH (A).
The average ethylene composition of the obtained EVOH (A) was 30.8 mol%, and the degree of saponification was 99.7 mol%.
In addition, when the ECD and Mw of the EVOH (A) were measured by the above method, they were 3.7 and 75000, respectively.
14750 × 75000 ^−0.75 = 3.3 <3.7
Thus, the expression (1) was satisfied.

70 parts of EVOH (A) obtained above and 30 parts of EVOH (B) (“Soarnol H4815” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having an ethylene content of 48 mol% and a saponification degree of 99.7 mol% were melt-kneaded. Thus, an EVOH composition of the present invention was obtained.
In addition, when the ECD and Mw of the EVOH (B) were measured by the above method, they were 2.8 and 80000, respectively.
14750 × 80000 ^−0.75 = 3.1> 2.8
Thus, it deviated from the expression (1).
Using the obtained EVOH composition, the transparency, the impact resistance of the heat seal part, and the gas barrier property were evaluated in the following manner.

(transparency)
The EVOH composition obtained above was supplied to a single screw extruder (attached to a coat hanger die with a die width of 450 mm), and a single layer film (thickness 30 μm) was produced under the following conditions.
[Single-layer film formation conditions]
Screw inner diameter 40mm (L / D = 26)
Screw shape of supply part 6D, compression part 13D, weighing part 7D
Full flight type screw screen mesh 90/90 mesh
Screw rotation speed 40rpm
Extrusion temperature C1: 180 ° C
C2: 200 ° C
C3: 220 ° C
C4: 220 ° C
H: 220 ° C
D1: 220 ° C
D2: 220 ° C

The internal haze value of the monolayer film obtained above was measured using a haze meter (“NDH-2000” manufactured by Nippon Denshoku Co., Ltd.) and evaluated as follows.
○ ・ ・ ・ Haze value is less than 0.5 × ・ ・ ・ 〃 is 0.5 or more

(Impact resistance)
Using the EVOH composition obtained above, a multilayer film was produced in the following manner.
[Manufacture of multilayer films]
An EVOH composition, polypropylene [“EA9” manufactured by Nippon Polychem Co., Ltd.] and an adhesive resin [maleic anhydride-modified low density polyethylene, “Modic AP L502” manufactured by Mitsubishi Chemical Co., Ltd.] were used to provide a three-layer three-layer inflation die. A multilayer film having a layer structure (thickness 30/10/90 μm) of EVOH composition layer / adhesive resin layer / polypropylene layer was obtained by supplying to a multilayer extrusion apparatus.
Two samples of 10 cm × 10 cm were cut from the obtained multilayer film, sealed in three directions, then filled with 50 cc of water as the contents, and heat-sealed at 140 ° C. under the condition of 0.5 kg / cm ² for 3 seconds. Then, 20 test specimens were prepared, and the number of damaged heat seal portions when they were dropped onto concrete from a height of about 1 meter above the ground (at 20 ° C. atmosphere) was evaluated and evaluated as follows.
○ ・ ・ ・ No more than 3 breakage × ・ ・ ・ 4 or more 〃

(Gas barrier properties)
About the multilayer film obtained above, oxygen permeability was measured under the conditions of 20 ° C. and 60% RH using an oxygen permeability measuring device [“OXTRAN 2/20” manufactured by MOCON Corporation]. In addition, 100% concentration oxygen gas was used as the test gas.

Example 2
In Example 1, the polymerization was started at 450 g of methanol, the ethylene pressure at the start of polymerization was 55 kg / cm ² , the polymerization start temperature was 42.5 ° C., and the temperature was raised at a rate of 5 ° C./hr. The same procedure was followed except that the temperature was changed to 5 ° C. and the ethylene pressure at the end of polymerization was changed to 60 kg / cm ^2. An EVOH having an average ethylene composition of 42.0 mol% and a saponification degree of 99.6 mol% ( A) was obtained.
Further, when the ECD and Mw of the EVOH (A) were measured by the above method, they were 3.5 and 80100, respectively, and substituted into the equation (1).
14750 × 80100 ^-0.75 = 3.1 <3.5
Thus, the expression (1) was satisfied.
40 parts of EVOH (A) obtained above and 60 parts of EVOH (B) having an ethylene content of 32 mol% and a saponification degree of 99.5 mol% [“SOANOL DC3212” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] were melt-kneaded. Thus, an EVOH composition of the present invention was obtained and evaluated in the same manner as in Example 1.
In addition, when ECD and Mw of the EVOH (B) were measured by the above method, they were 2.4 and 88000, respectively.
14750 × 88000 ^−0.75 = 2.9> 2.4
Thus, it deviated from the expression (1).

Example 3
In Example 1, the same procedure was followed except that the amount of methanol charged was 25 g, the ethylene pressure was 38 kg / cm ² , and the polymerization temperature was 61 ° C. The average ethylene composition was 30.7 mol%, and the saponification degree was 99.7. Mol% EVOH (A) was obtained.
When the ECD and Mw of the EVOH (A) were measured by the above method, they were 2.0 and 140000, respectively.
14750 × 140000 ^-0.75 = 2.0 <2.2
Thus, the expression (1) was satisfied.
Separately, in accordance with Example 1, 1250 g of methanol was charged, the polymerization temperature was 60 ° C., and the ethylene pressure at the start of polymerization was 48.5 kg / cm ² , and the polymerization was started, and 1.5 kg / cm ² · hr The same procedure was performed except that the pressure was changed to 66.5 kg / cm ² while increasing the pressure at a rate of EVOH (B) having an average ethylene composition of 41.4 mol% and a saponification degree of 99.7 mol%. It was.
When the EVOH (B) ECD and Mw were measured by the above method, they were 3.5 and 64000, respectively.
14750 × 64000 ^-0.75 = 3.7 <4.5
Thus, the expression (1) was satisfied.
The EVOH composition of the present invention was obtained by melt-kneading 70 parts of EVOH (A) and 30 parts of EVOH (B) obtained above, and evaluated in the same manner as in Example 1.

Comparative Example 1
70 parts of EVOH (B) used in Example 1 and 30 parts of EVOH (B) used in Example 2 were melt-kneaded to obtain an EVOH composition, which was evaluated in the same manner as in Example 1.

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

[Table 1]
Transparency Impact resistance Gas barrier properties *
Example 1 ○ ○ 1.0
〃 2 ○ ○ 0.8
４ 4 ○ ○ 0.6
Comparative Example 1 × × 1.8
* Unit is cc / m ² . day. 20m thickness conversion value at atm

Since the EVOH composition of the present invention is a blend of two types of EVOH having a specific ethylene distribution, it has excellent impact resistance at the heat seal portion when it is molded into a film or the like and heat sealed, and is transparent. It has excellent gas barrier properties and can be molded into cups, trays, tubes and other containers, stretched film bags and lids, food, beverages, pharmaceuticals, cosmetics, industrial chemicals, detergents, agricultural chemicals, fuels, etc. It can be effectively used as various packaging materials.

Claims (4)

A saponified ethylene-vinyl acetate copolymer composition comprising two saponified ethylene-vinyl acetate copolymers and at least one of which satisfies the following formula (1):
14750 × Mw ^−0.75 ≦ ECD (1)
(Here, ECD is the standard deviation of ethylene composition distribution when re-acetylated ethylene-vinyl acetate copolymer saponified product is measured by liquid chromatography equipped with an evaporative light scattering detector, and Mw is tetrahydrofuran as a solvent. The weight average molecular weight of the reacetylated product of the saponified ethylene-vinyl acetate copolymer measured by GPC using polystyrene as a standard.)   The ethylene-vinyl acetate copolymer saponified composition according to claim 1, wherein the difference in ethylene content between the two saponified ethylene-vinyl acetate copolymers is 4 mol% or more.   A multilayer laminate comprising a layer containing the saponified ethylene-vinyl acetate copolymer composition according to claim 1 or 2 as an innermost layer. The multilayer laminate according to claim 3, wherein the multilayer laminate is a container.