JP2000063528A - Pellet of saponified ethylene-vinyl acetate copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject pellet which is very little in fusion, breaking and crack and occurrence of fine powder even by temperature change in transportation, state in loading, vibration etc., by specifyin storage elastic modulus. SOLUTION: This pellet has 8×107 to 1×109 Pa, preferably 9×107 to 5×10 Pa storage elastic modulus (at 200 deg.C) and preferably has 0.1-1,000 ppm <=5C alcohol(e.g. methanol) content, 10-60 mol.% ethylene content and >=90% saponification degree and more preferably has 5-5,000 ppm acetic acid content, 10-5,000 ppm sodium acetate and 0.01-10 weight ratio of acetic acid to sodium acetate. The storage elastic modulus is a value measured when 10 Hz vibration is applied and can be measured by DMA (Dynamic Mechanical Analyzer), etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH).
More specifically, the present invention relates to an EVOH pellet having excellent fusion moldability, which is extremely free from fusion, cracking, chipping, and generation of fine powder during transportation.

[0002]

2. Description of the Related Art Generally, EVOH is excellent in transparency, gas barrier property, aroma retaining property, solvent resistance, oil resistance and the like, and taking advantage of such characteristics, food packaging materials, pharmaceutical packaging materials,
It is used after being molded into films and sheets of industrial chemical packaging materials, agricultural chemical packaging materials, and containers such as bottles.

[0003]

[Problems to be Solved by the Invention] However, EVO
When transporting H pellets, they are usually wrapped in kraft paper, etc., which is moisture-proofed with an aluminum inner bag, etc., but due to temperature changes during loading, loading conditions, vibrations, etc., the pellets may melt. There is a problem in that it may occur, or cracks, chips, and fine powder may occur, resulting in difficulty in stable melt molding.

[0004]

Therefore, the present inventors have
As a result of earnest research in view of the present situation, EVOH having a storage elastic modulus at 20 ° C. of 8 × 10 ⁷ to 1 × 10 ⁹ Pa.
Even if the pellets do not cause fusion due to temperature changes during loading of EVOH pellets, loading conditions, vibrations, etc., there is little cracking, chipping, or generation of fine powder, and excellent melt moldability. The present invention has been completed and the present invention has been completed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The EVOH pellets of the present invention have storage elasticity at 20 ° C.
Rate is 8 × 10⁷~ 1 x 10⁹(Further 9 × 10⁷ ~ 5 x 1
0⁸) Pa, the storage modulus is 8 × 10 ⁷Less than Pa
In this case, fusion between pellets is likely to occur during transportation.
1 x 10⁹If it exceeds Pa, the pellet will crack during transportation,
It is not suitable because chips and fine powder are likely to be generated.

The storage elastic modulus is a value measured when a vibration of 10 Hz is applied, and is a DMA (Dynamic Mec
In the present invention, EVOH pellets can be measured at 10 to 50 ° C.
While increasing the temperature at a rate of ° C / min, the storage elastic modulus was continuously measured by the DMA, and the measured value at 20 ° C was measured by EVOH.
The storage modulus of the pellet was used.

Further, the EVOH (pellets) has an ethylene content of 10 to 60 mol% (further 20 to 55 mol%), a saponification degree of 90 mol% or higher (further 95 mol% or higher), and a melt index ( 210 ℃, load 2160
g) is 0.5 to 100 g / 10 minutes (further 1 to 50 g /
10 minutes), and the ethylene content is 10
If it is less than mol%, the gas barrier property at high humidity is deteriorated, and 6
When it exceeds 0 mol% or when the degree of saponification is less than 90 mol%, gas barrier properties, oil resistance and chemical resistance are deteriorated, which is not preferable, and when the melt index is smaller than the range. In particular, when the inside of the extruder is in a high torque state at the time of molding, extrusion processing becomes difficult, and when it is larger than the range, on the contrary, since the torque is low, the extrusion processability becomes unstable, which is not preferable.

The EVOH used in the present invention contains a small amount of modifying components such as unsaturated carboxylic acid, its anhydride,
Any modified polymerization component such as salts, esters, α-olefins, vinyl ethers, vinylsilanes, nitriles and amides may be contained. Further, in the present invention,
EVO having ethylene content and degree of saponification in the above range
If H, it may be used alone or in combination of two or more different EVOH.

The EVOH of the present invention having the above physical properties
In obtaining the pellets, any method such as adjusting the volatile content of EVOH or post-treating the EVOH pellets with water or the like is adopted, but there is no particular limitation. The content of alcohol having 5 or less carbon atoms in EVOH is 0.1 to 100
The method of adjusting to 0 ppm (further 0.5 to 150 ppm) is one of the methods for adjusting the elastic modulus, and is highly practical in terms of the physical properties of the obtained film. The alcohol content is 0.1
If it is less than ppm, streaks and irregularities are generated on the surface of the formed film to lose smoothness, and if it exceeds 1000 ppm, foaming is likely to occur in the formed film, which is not preferable.

Examples of the alcohol having 5 or less carbon atoms include methanol, ethanol, propyl alcohol, butyl alcohol, etc., but methanol is industrially preferable.

Further, in the present invention, a method of controlling the content of acetic acid (a) is also preferable as a method of adjusting the elastic modulus, and the content is 5 to 5000 ppm, further 20 to 50 ppm.
0 ppm is preferred. Outside this range, the adverse effects on the physical properties such as fusion of pellets, cracking, chipping, and generation of fine powder become remarkable, and the extrusion stability during film formation (molding) becomes poor,
This is not preferable because the formed film has poor appearance characteristics. Further, in the present invention, when acetic acid (a) is present in EVOH, the content of sodium acetate (b) is controlled, that is, by setting the content to 10 to 5000 ppm, further 100 to 1000 ppm, It is possible to improve the extrusion stability during film formation (molding) and the appearance characteristics of the molded film. In particular, by setting the weight ratio (a / b) of acetic acid (a) and sodium acetate (b) to 0.01 to 10, and further to 0.1 to 5, coloring of the molded article and generation of gel in the molded article are caused. To be prevented.

As a method for adjusting the content of the alcohol, acetic acid (a), sodium acetate (b), etc., and the weight ratio of acetic acid (a) and sodium acetate (b), EVOH pellets (containing water / methanol) are used. Is washed with water, then immersed in an acetic acid aqueous solution, and then dried to adjust the content. EVOH pellets (containing water / methanol) are washed with water, then immersed in an acetic acid aqueous solution, and a sodium acetate aqueous solution is further added. (Spraying), then adjusting the content by drying, after washing the EVOH pellets (containing water / methanol) with water, adding (spraying) an aqueous acetic acid solution and an aqueous sodium acetate solution, and then drying. There is a method of adjusting the content, etc., but the method is preferable, and such a method will be described below.

EVOH pellets are usually obtained by copolymerizing ethylene and vinyl acetate in an alcohol solvent, saponifying with an alkali, etc., depositing strands in a methanol / water coagulation bath in strands, and then cutting. . The pellets usually contain 10 to 80% by weight of alcohol having 5 or less carbon atoms, 0.001 to 5% by weight of acetic acid, and 0.01 to 5% by weight of sodium acetate.

The EVOH pellets are then washed with water, which is carried out in a water bath at 10 to 60 ° C. By washing with water, the content of alcohol having 5 or less carbon atoms, acetic acid, and sodium acetate in EVOH is adjusted,
Further, oligomers and impurities are removed. Washing with EV
200 to 1000 parts by weight (preferably 300 to 600 parts by weight) of water per 100 parts by weight of OH pellets, 20
~ 50 ° C (25-35 ° C), 0.5-5 hours, 1-5
It is performed once (preferably once).

Then, the EVOH pellets are immersed in an aqueous acetic acid solution. As the dipping method, an acetic acid aqueous solution of 3% or less (preferably 0.3 to 1.5%) is used in an amount of 200 to 1000 parts by weight (preferably 300 to 600 parts by weight) with respect to 100 parts by weight of EVOH pellets. 20-50 ° C
(25 to 35 ° C.), water washing for 0.5 to 5 hours is performed 1 to 3 times (preferably 1 time). By the operations of washing with water and immersion in an acetic acid aqueous solution described above, usually 100 to 10,000 ppm of alcohol having 5 or less carbon atoms and 1
00-10,000 ppm, sodium acetate (b) 10
It is preferably adjusted to 0 to 10000 ppm.

Next, the EVOH pellets are brought into contact with a heating gas and dried. Air or an inert gas (nitrogen gas, helium gas, argon gas, etc.) is used as the heating gas used at this time, and the temperature of the heating gas is 40.
~ 150 ° C is preferred, more preferably 70-130 ° C, especially 1
It is 10-125 degreeC. If the temperature is lower than 40 ° C., the drying time becomes long, which is economically disadvantageous. On the contrary, if the temperature exceeds 150 ° C., gel and fish eyes are likely to occur frequently in the formed film, which is not preferable. The drying time is preferably 10 minutes to 96 hours, more preferably 1 to 48 hours, and especially 15 to 25 hours. Carbon number is 5 by the above drying
The following alcohols are 0.1 to 1000 ppm, acetic acid (a) is 5 to 5000 ppm, and sodium acetate (b) is 10 to 5000 ppm [(a) / (b) = 0.01 to 1].
0] is preferable.

Specific examples of the drying method include static drying, fluidized drying and a combination of these methods. For the static drying, a batch type aeration flow box dryer, a band dryer and a tunnel are used. Dryers and vertical dryers, for fluidized drying, cylindrical / groove type stirring dryers, cylindrical dryers (tower type, box type)
A rotary dryer, (semi-continuous two-stage, continuous horizontal multi-chamber, continuous perforated plate multi-stage) fluidized bed dryer, oscillating fluidized bed dryer, conical rotary dryer is used.

The EVOH pellets thus obtained have no fusion of the pellets during transportation, little cracking, chipping, and generation of fine powder, less torque fluctuation and change in discharge amount during melt molding, and more uniform thickness. Excellent melt moldability that it is possible to obtain a molded product such as a film or sheet having excellent properties, the pellets are pellets, films, sheets, containers,
It is often molded into fibers, rods, tubes, various molded products, and the like, and is often melt-molded again using crushed products (such as when reusing collected products) or pellets.

As a melt molding method, an extrusion molding method (T-
Die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and injection molding methods are mainly adopted.
The melt molding temperature is often selected from the range of 150 to 300 ° C. The EVOH pellets are also frequently used for laminates, and in particular, they are used as a laminate in which a thermoplastic resin layer is laminated on at least one surface of a layer made of EVOH.

In producing the laminate, EVO is used.
Another substrate is laminated on one side or both sides of the H layer. As a laminating method, for example, the EVOH film,
A method of melt-extruding a thermoplastic resin into a sheet, conversely, a method of melt-extruding the EVOH into a base material such as a thermoplastic resin,
Method of co-extruding VOH and other thermoplastic resin, and further, the EVOH film and sheet obtained in the present invention, the film of other base material, and the sheet are made of organic titanium compound, isocyanate compound, polyester compound, polyurethane Examples include a method of dry laminating using a known adhesive such as a compound.

In the case of coextrusion, the other resin is linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene. -Acrylic ester copolymer, polypropylene, propylene-α-olefin (having 4 to 20 carbon atoms)
Α-olefin) copolymer, polybutene, homopolymer or copolymer of olefin such as polypentene, or a polyolefin in a broad sense such as homo- or copolymer of these olefins graft-modified with unsaturated carboxylic acid or its ester Examples include resin, polyester, polyamide, copolyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, PET, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene and chlorinated polypropylene. EVOH can also be coextruded. Among the above, from the viewpoint of ease of coextrusion film formation and practicality of film physical properties (particularly strength), polypropylene, polyamide,
Polyethylene, ethylene-vinyl acetate copolymer, polystyrene and PET are preferably used.

Furthermore, a molded product such as a film or sheet is once obtained from the EVOH pellets obtained by the method of the present invention, and another substrate is extrusion coated on the molded product, or a film of another substrate,
When a sheet or the like is laminated using an adhesive, any substrate (paper, metal foil, uniaxially or biaxially stretched plastic film or sheet, woven cloth, non-woven cloth, metallic cotton, wood, etc. other than the above-mentioned thermoplastic resin is used. ) Can be used. The layer structure of the laminate is such that the EVOH layer is x (x ₁ , x ₂ , ...) And another substrate, for example, a thermoplastic resin layer is y (y ₁ , y ₂ , ...).
And if it is a film, sheet, or bottle, then x
Not only the two-layer structure of / y, but also y / x / y, x / y / x,
_{x 1 / x 2 / y,} x / y 1 / y 2, y 2 / y 1 / x / y 1 / y 2
Etc., any combination is possible, and in the filament form, x and y are bimetal type, core (x) -sheath (y) type, core (y) -sheath (x) type, eccentric core-sheath type, etc. Is possible.

The laminate is used in various shapes as it is, but it is also preferable to subject it to a stretching treatment in order to further improve the physical properties of the laminate.
It may be either uniaxially stretched or biaxially stretched, and it is better in terms of physical properties to stretch as high as possible, and a stretched film or stretched sheet that does not cause pinholes or cracks during stretching, stretching unevenness, delamination, etc. Is obtained.

As the stretching method, in addition to the roll stretching method, the tenter stretching method, the tubular stretching method, the stretching blow method, etc.,
Of the deep drawing and vacuum forming, those having a high draw ratio can be used. In the case of biaxial stretching, either simultaneous biaxial stretching method or sequential biaxial stretching method can be adopted. Stretching temperature is 80
To 170 ° C., preferably about 100 to 160 ° C.

After the stretching is completed in this way, heat setting is then carried out. The heat setting can be carried out by a known means, and the stretched film is heat-treated at 80 to 170 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds while keeping the stretched state. When used for heat shrink packaging of raw meat, processed meat, cheese, etc., the product film is not heat set after stretching, and the raw meat, processed meat, cheese, etc. are stored in the film, ~ 130 ° C, preferably 70-120
The film is heat-treated at 2 ° C. for about 2 to 300 seconds to heat-shrink and tightly pack the film.

The laminate thus obtained may have any shape, and examples thereof include films, sheets, tapes, bottles, pipes, filaments and modified cross-section extrudates. In addition, the obtained laminate may be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry laminating treatment,
Solution or melt coating treatment, bag making processing, deep drawing processing, box processing, tube processing, split processing and the like can be performed. The film, sheet or container obtained as described above is useful as various packaging materials for foods, pharmaceuticals, industrial chemicals, agricultural chemicals and the like.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, "parts" means "parts by weight", and "%" means "% by weight" unless otherwise specified.
Means Example 1 1,000 parts of a 40% methanol solution of an ethylene-vinyl acetate copolymer having an ethylene content of 40 mol% was placed in a pressure resistant reactor and heated to 110 ° C while stirring. Subsequently, 40 parts of a 6% methanol solution of sodium hydroxide and 2,500 parts of methanol are continuously charged, and methyl acetate produced as a by-product and excess methanol are distilled from the system.
The saponification reaction was carried out for 5 hours to obtain a saponified ethylene-vinyl acetate copolymer solution having a saponification degree of the vinyl acetate component of 99.0 mol%. Next, an aqueous solution of methanol with a water content of 30% 6
00 parts were azeotropically fed to the solution at 100-110 ° C,
At a pressure of 3 kg / cm ² G, the concentration of the resin component in the solution was 40
The methanol was distilled off until the amount reached 0.1% to obtain a transparent homogeneous methanol / water solution (the methanol in the solution was 40%).
A methanol solution of the saponified product was extruded from a nozzle into a water tank in a strand shape. After the solidification, the strand was cut with a cutter to produce white pellets (1) having a diameter of 4 mm and a length of 4 mm. The pellet (1) had a methanol content of 38%, an acetic acid (a) content of 3000 ppm, and a sodium acetate (b) content of 15000 ppm.

Next, 100 parts of the obtained pellet (1) was put into 400 parts of 30 ° C. warm water, stirred for about 60 minutes and washed with water, and then washed with water and immersed in 400 parts of a 1% aqueous acetic acid solution.
The methanol content of the pellet after immersion is 5000 pp
m, the acetic acid (a) content was 2500 ppm, and the sodium acetate (b) content was 500 ppm. Using a batch-type fluidized bed dryer, the nitrogen gas in the atmosphere of 120 ° C
After contacting for a period of time, EVOH pellets having a methanol content of 100 ppm, an acetic acid (a) content of 200 ppm, and a sodium acetate (b) content of 500 ppm [(a) / (b) = 5 (weight ratio)] were obtained. 2 of such EVOH pellets
The storage elastic modulus at 0 ° C. was 1 × 10 ⁸ Pa.

With respect to the EVOH pellets thus obtained, evaluation of the pellets and EVO using the pellets were carried out as follows.
The formability of the H film was evaluated. (A) Fusing of pellets 25 kg of the EVOH pellets described above are put in aluminum inner bag kraft paper (length 800 mm, width 500 mm, thickness 150 mm), 10 bags are piled up, left at 60 ° C. for 7 days, and then placed in the bottom stage. The EVOH pellets in the above bag were visually evaluated as follows. ○: No fusion was observed. Δ: 1 to 10 fusion bonds are observed. X: 11 or more fusion bonds are seen. (B) Cracking or chipping of pellets 25 kg of EVOH pellets was put in a blender, rotated at room temperature for 10 hours, taken out, and visually evaluated as follows. ○: No cracking of the pellet was observed. Δ: 1 to 10 cracks and chips are observed. X: 11 or more cracks and chips were observed. (C) Generation of fine powder The content obtained by rotating at room temperature for 10 hours by the above method was taken out, passed through a 100 μm sieve, and the weight of the fine powder passing through the sieve was measured, and evaluated as follows. ◯: 0 to less than 2 g △: less than 2 to 10 g ×: 10 g or more

On the other hand, the EVOH pellets thus obtained were fed to a single-screw extruder equipped with a T-die to prepare an EVOH having a thickness of 40 μm.
The film was continuously molded for 96 hours and evaluated as follows. The film forming conditions by the single screw extruder were as follows.

(D) Torque fluctuation Extruder motor load during continuous film formation (screw rotation speed 4
It was determined by the variation of the screw torque A (ampere) at 0 rpm and evaluated as follows. ○ ・ ・ ・ Variation of less than ± 5% △ ・ ・ ・ Variation of ± 5 to less than ± 10% × ・ ・ ・ Variation of ± 10% or more (e) Change in discharge rate With extruder (40 rpm) during continuous film formation The change in the discharge amount of was determined and evaluated as follows. ○ ・ ・ ・ Variation of less than ± 5% △ ・ ・ ・ Variation of ± 5 to less than ± 10% × ・ ・ ・ Variation of ± 10% or more

(F) Film thickness change The thickness of the film in the MD (longitudinal) direction is measured every hour,
The variation ratio was obtained and evaluated as follows. ○ ・ ・ ・ less than ± 5% △ ・ ・ ・ ± 5 to less than ± 10% × ・ ・ ・ ± 10% or more (g) Film appearance The number of fish eyes per 100 cm ² (10 cm × 10 cm) of the film was measured. Was evaluated as follows. ○ ・ ・ ・ 0-3 pieces △ ・ ・ ・ 4-20 pieces × ・ ・ ・ 21 pieces or more

Example 2 In the same manner as in Example 1, an EV having a saponification degree of 99.0 mol% was used.
OH was obtained. Next, 60% aqueous methanol solution with a water content of 30%
0 part was azeotropically fed to the solution, and the concentration of the resin component in the solution was 40% at 100 to 110 ° C. and a pressure of 3 kg / cm ² G.
Methanol is distilled off until it becomes clear methanol /
A homogeneous solution of water (40% methanol in the solution) was obtained. A methanol solution of the saponified product was extruded from a nozzle into a water tank in a strand shape. After the solidification, the strand was cut with a cutter to produce white pellets (1) having a diameter of 4 mm and a length of 4 mm. The pellet (1) had a methanol content of 38%, an acetic acid (a) content of 3000 ppm, and a sodium acetate (b) content of 15000 ppm.
Next, 100 parts of the obtained pellet (1) was poured into 400 parts of 30 ° C. warm water, and the mixture was stirred for about 60 minutes and washed with water.
After washing with water, it was immersed in 400 parts of a 0.3% acetic acid aqueous solution. The pellets after immersion had a methanol content of 5000 ppm, an acetic acid (a) content of 1000 ppm, and a sodium acetate (b) content of 500 ppm. Nitrogen gas was brought into contact with the batch type tower fluidized bed dryer in an atmosphere at 118 ° C. for 20 hours to give a methanol content of 120 ppm, an acetic acid (a) content of 300 ppm, and a sodium acetate (b) content of 500 ppm.
ppm [(a) / (b) = 0.6 (weight ratio)] EVO
H pellets were obtained. The storage elastic modulus of the EVOH pellets at 20 ° C. was 9 × 10 ⁷ Pa. Such E
The same evaluation was performed using VOH pellets.

Example 3 An experiment was conducted in the same manner as in Example 1 except that an ethylene-vinyl acetate copolymer having an ethylene content of 30 mol% was used to produce white pellets (1). The pellet (1) has a methanol content of 20% and an acetic acid (a) content of 3000 p.
pm, sodium acetate (b) content is 15000ppm
Met.

Then, 100 parts of the obtained pellet (1) was put into 700 parts of warm water at 30 ° C., and the mixture was stirred for about 60 minutes and washed with water. After washing with water, it was immersed in 400 parts of a 1% aqueous acetic acid solution. Methanol content of the pellet after immersion is 4000p
pm, the acetic acid (a) content was 2300 ppm, and the sodium acetate (b) content was 400 ppm. Using a batch-type fluidized bed dryer, nitrogen gas was stored in an atmosphere of 120 ° C for 20
After contacting for a period of time, EVOH pellets having a methanol content of 80 ppm, an acetic acid (a) content of 200 ppm, and a sodium acetate (b) content of 400 ppm [(a) / (b) = 5 (weight ratio)] were obtained. 2 of such EVOH pellets
The storage elastic modulus at 0 ° C. was 2 × 10 ⁸ Pa. The EVOH pellets were used for the same evaluation.

Comparative Example 1 In Example 1, 100 parts of EVOH pellets (1) was added to 100 parts of warm water at 30 ° C. and stirred for about 60 minutes to obtain washed pellets. After washing with water, it was immersed in 400 parts of a 1% aqueous acetic acid solution. Methanol content of pellets after immersion is 7,000
ppm, acetic acid (a) content was 2500 ppm, and sodium acetate (b) content was 700 ppm. Then, using a batch-type tower-type fluidized dryer, nitrogen gas was contacted in an atmosphere of 105 ° C. for 16 hours to give a methanol content of 2000 pp.
m, acetic acid (a) content 300 ppm, sodium acetate (b) content 700 ppm [(a) / (b) = 0.73
(Weight ratio)] EVOH pellets were produced. Such E
Storage modulus of VOH pellets at 20 ° C is 5 x 10
It was ⁷ Pa. The EVOH pellets were used for the same evaluation.

Comparative Example 2 In Example 1, 100 parts of EVOH pellets (1) were poured into 600 parts of warm water at 40 ° C. and stirred for about 60 minutes to obtain washed pellets, which were washed with water and immersed in 400 parts of a 2% acetic acid aqueous solution. did. Methanol content of pellets after immersion 4000
ppm, acetic acid content was 3000 ppm, and sodium acetate content was 20 ppm. Nitrogen gas was contacted for 36 hours in an atmosphere of 135 ° C. by a batch-type column-type fluidized dryer to obtain a methanol content of 0.01 ppm, an acetic acid (a) content of 10 ppm, and a sodium acetate (b) content of 20 ppm.
EVOH pellets of [(a) / (b) = 0.5 (weight ratio)] were produced. The storage elastic modulus at 20 ° C. of such EVOH pellets was 3 × 10 ⁹ Pa. Such EV
The same evaluation was performed using OH pellets. The evaluation results of Examples and Comparative Examples are shown in Tables 1 and 2.

[0038]

[Table 1]

[0039]

[Table 2] (d) (e) (f) ( g ) Torque fluctuation Discharge rate change Film thickness change Film appearance Example 1 ○ ○ ○ ○ 〃 2 ○ ○ ○ ○ 〃 3 ○ ○ ○ ○ Comparative example 1 × × × × 〃 2 × × × ○

[0040]

Since the EVOH pellets of the present invention have specific physical property values, the pellets may be fused even when the temperature of the pellets changes during transportation, loading conditions, vibrations, or the like. Molded products such as films and sheets that do not have cracks, chips, and fine powders, have excellent melt moldability, have little torque fluctuation and discharge amount change during melt molding, and have excellent thickness uniformity. It is very useful for applications such as foods, pharmaceuticals, agricultural chemicals, films for packaging industrial chemicals, sheets, tubes, bags and containers.

[Procedure amendment]

[Submission date] October 15, 1999 (1999.10.
15)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Then, 100 parts of the obtained pellets (1) were put into 400 parts of warm water at 30 ° C., stirred for about 60 minutes and washed with water, and then washed with water and immersed in 400 parts of 1% acetic acid aqueous solution.
The methanol content of the pellet after immersion is 5000 pp
m, the acetic acid (a) content was 2500 ppm, and the sodium acetate (b) content was 500 ppm. Using a batch-type fluidized bed dryer, the nitrogen gas in the atmosphere of 120 ° C
After contacting for a period of time, EVOH pellets having a methanol content of 100 ppm, an acetic acid (a) content of 200 ppm, and a sodium acetate (b) content of 500 ppm [(a) / (b) = 0.4 (weight ratio)] were obtained. . The storage elastic modulus at 20 ° C. of such EVOH pellets was 1 × 10 ⁸ Pa.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

Next, 100 parts of the obtained pellet (1) was put into 700 parts of hot water at 30 ° C., and the mixture was stirred for about 60 minutes and washed with water. After washing with water, it was immersed in 400 parts of a 1% aqueous acetic acid solution. Methanol content of the pellet after immersion is 4000p
pm, the acetic acid (a) content was 2300 ppm, and the sodium acetate (b) content was 400 ppm. Using a batch-type fluidized bed dryer, nitrogen gas was stored in an atmosphere of 120 ° C for 20
After contacting for a period of time, EVOH pellets having a methanol content of 80 ppm, an acetic acid (a) content of 200 ppm, and a sodium acetate (b) content of 400 ppm [(a) / (b) = 0.5 (weight ratio)] were obtained. . The storage elastic modulus at 20 ° C. of such EVOH pellets was 1 × 10 ⁸ Pa. The EVOH pellets were used for the same evaluation.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Comparative Example 1 In Example 1, 100 parts of EVOH pellets (1) were added to 100 parts of warm water at 30 ° C. and stirred for about 60 minutes to obtain washed pellets. After washing with water, it was immersed in 400 parts of a 1% aqueous acetic acid solution. Methanol content of pellets after immersion is 700
0 ppm, acetic acid (a) content was 2500 ppm, and sodium acetate (b) content was 700 ppm. Then, using a batch-type tower fluidized bed dryer, nitrogen gas was contacted for 16 hours in an atmosphere of 105 ° C. to obtain a methanol content of 2000.
ppm, acetic acid (a) content of 300 ppm, sodium acetate (b) content of 700 ppm [(a) / (b) = 0.
43 (weight ratio)] EVOH pellets were produced. The storage elastic modulus at 20 ° C. of such EVOH pellets is 5 ×
It was 10 ⁷ Pa. The EVOH pellets were used for the same evaluation.

Claims (5)

[Claims] 1. A storage elastic modulus at 20 ° C. of 8 × 10 ⁷
~ 1 × 10 ⁹ Pa, ethylene-vinyl acetate copolymer saponified pellets, characterized in. 2. An alcohol having a carbon number of 5 or less is 0.1-0.1%.
The ethylene-vinyl acetate copolymer saponified pellet according to claim 1, which contains 1000 ppm, has an ethylene content of 10 to 60 mol% and a saponification degree of 90 mol% or more. 3. The saponified pellet of ethylene-vinyl acetate copolymer according to claim 1, which contains 5-5000 ppm of acetic acid (a). 4. Sodium acetate (b) is added in an amount of 10 to 5,000.
The saponified pellet of ethylene-vinyl acetate copolymer according to any one of claims 1 to 3, wherein the pellet contains saponified ethylene-vinyl acetate copolymer. 5. The ethylene-vinyl acetate copolymer according to claim 4, wherein the weight ratio (a / b) of acetic acid (a) and sodium acetate (b) contained is 0.01 to 10. Saponified pellets.