JP2674757B2 - Ethylene-vinyl alcohol copolymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial applications   The present invention is based on the heating time and discharge in the Koka flow tester.
Ethylene with unique flow properties in terms of velocity
-Vinyl alcohol-based copolymer (hereinafter referred to as EVOH) composition
About things. B. Conventional technology   EVOH has gas barrier properties and high transparency, and is oil resistant and protective.
It is a useful polymer material with excellent fragrance, and can be used as a film or film.
It is widely used for containers and containers.   EVOH is usually a caustic mixture of ethylene-vinyl acetate polymer.
It can be obtained by adding potassium to perform saponification.
When melt molding the compound as it is, it is easy to thermally decompose,
The melt viscosity is significantly reduced and it is colored violently before use.
I can't use it. Many conventional measures have been taken to improve this.
Have been For example, wash EVOH thoroughly with water,
By adding or immersing in an acid solution,
What is improved to some extent is that it is disclosed in Japanese Patent Publication No. 46376/1974.
JP-A-48-25048, JP-A-51-88544, JP-A-51-88545
And Japanese Examined Patent Publication No. 55-19242. Again
Addition of metal salts is considered to have a remarkable thermal stabilizing effect.
It is also possible to improve the melt moldability by adding, for example, JP-A-52-95.
4, JP-A-52-955, JP-A-56-41204, etc.
Have been.   These methods mainly reduce the change in viscosity with time during melting.
Intended to melt, and certainly melt for a short time
In molding, it is possible to obtain a molded product with a good appearance.
You. However, continuous melt molding for a long time, for example 24 hours or more
Doing so causes gel-like or streaky spots on the molded product.
And the appearance becomes poor, and finally a molded product that can withstand use is obtained.
Can not be. C. Problems to be solved by the invention   The present invention provides a gel-like material for a molded product even if it is melt-molded for a long time.
Alternatively, an EVOH composition without streaky unevenness is obtained.
Things. D. Means for solving problems   EVOH, sodium, potassium acetate to the metal salt
Converted 0.001 to 0.05% by weight, pKa (acidity index at 25 ℃)
Acidic substances with a boiling point under atmospheric pressure of 180 ° C or higher under 3.5 and above 0.002〜
0.2 wt%, acid with a pKa of 3.5 or more and a boiling point of 120 ° C or less under normal pressure
0.01 to 0.2% by weight and general formula MxAly (OH)
_{2x + 3y-2Z}(A) z ・ aH_aO (M is Mg, Ca, or Zn, A is CO_Three
Or HPO_Four, x, y, z, a are positive numbers)
A composition containing 0.01 to 5% by weight of the ito compound,
The melting point of the ethylene-vinyl alcohol copolymer {DS
Main heat absorption pi due to C (scanning speed 10 ° C / min)
Temperature of 10 to 80 ° C higher than at least one point
The heating time and discharge speed of the high flow tester
In relation to, the composition is exhaled for at least 15 minutes.
The speed does not increase substantially and the time is less than 2 minutes after 15 minutes.
The discharge speed at the desired heating time is the same as the discharge speed after 15 minutes.
It is in the range of 1/10 to 50 times, and within 10 hours after 2 hours
Discharge rate at any heating time of at least once after 15 minutes
The flow characteristics that are within the range of 2 to 50 times the discharge speed of
Shown is an EVOH composition. E. More Detailed Description of the Invention   In order to obtain a molded product having an extremely good appearance in the present invention
Suitable EVOH is saponified ethylene-vinyl acetate copolymer
As a product or third adult, 10 units for an adult vinyl acetate.
After copolymerizing less than 1% olefinic unsaturated monomer,
Ethylene-vinyl acetate copolymer copolymer obtained by saponification
And an ethylene content of 20 to 60 mol%, preferably 20
~ 55 mol% and saponification of the vinyl acetate component of the copolymer
Those with a degree of 95% or more are suitable. Ethylene content 20
If it is less than mol%, the molded article will have properties such as water resistance and hot water resistance.
Not only the performance decreases, but EVOH itself tends to gel
The increase in the number of fish eyes and the occurrence of streaks become noticeable.
The effects of the present invention are less likely to be exhibited. Also contains ethylene
Amount exceeds 60 mol% or saponification degree is less than 95%
The gas barrier property is reduced, and the original EVOH characteristics are retained.
No longer.   EVOH is usually an alcohol of ethylene-vinyl acetate copolymer.
Solution in caustic or alkali metal alcohol
Of sodium acetate, which is a by-product of saponification after saponification.
It is obtained by washing and removing the solder and the like with water.
However, if melt molding is performed as it is, thermal decomposition is severe and the melt viscosity is high.
It will not be able to be used because it will be severely colored and will be severely colored
No. Then add acid or soak in acid solution or
Operations such as adding a combination of some metal salts and acid
It is not possible to improve the moldability by such a method.
Generally known. In particular, JP-B-55-19242 and JP-A-51
-91988, JP 52-954, JP 52-955, JP
As disclosed in Japanese Patent Publication No. 56-41204,
For the treatment of adding an acid or a combination of certain metal salts and acids
Of the melt viscosity during melt molding
It is traditionally said that a small amount has good moldability.
Was. Certainly this is true of short-time melt molding.
It is a fruit, and a molded product with good appearance and less coloring is obtained.
You. However, continuous melt molding for a long time, for example 24 hours or more
As a result, the operating time becomes longer and
Causes gel-like or streaky unevenness, and EVOH
Coextrusion or Co-injection Multilayer Lamination of Polyamide and Hydrophobic Thermoplastic Resin
Body, especially ethylenically unsaturated carboxylic acid
A thermoplastic resin modified with acid anhydride is used as an interlayer adhesive layer.
Gels in coextruded or co-injected multilayer laminates
An interface instability phenomenon occurs during co-extrusion or co-injection as it occurs.
However, a wavy appearance defect appears on the whole. A fierce place
In this case, the unevenness on the entire surface becomes severe, and the bite of the stratum is eating.
It will be perforated, perforated, and torn. Appearance is low
Even if it is in a state, there is a fine pattern that becomes a satin finish on the entire surface,
There may be a pattern. Co-extrusion with poor appearance
If the product or co-injection product is post-processed, the appearance defect will be further aided.
It is lengthened to form a net-like pattern on the entire surface. Coextrusion or co
Such wavy surface roughness on ejection, satin finish is multi-layered
It is related to the stability of the flow. If the flow is unstable,
If the surface is rough, wavy surface roughness, and to a lesser extent, satin,
It appears as a streak.   However, as described above, the present inventors
EVOH prepared to exhibit a special viscosity change "and appropriate
Unexpectedly continuous melting for a long time when melt-molded at various temperatures
In melt molding, the appearance of molded products, especially multilayer laminates, is poor.
We have found the fact that this can be prevented significantly.   That is, the present invention is a formula for increasing the viscosity change of EVOH over time.
Measured by a flow tester, the melting point of the EVOH is 10 to
Heating time and discharge at at least one point of 80 ℃ higher temperature
In terms of speed, the discharge speed must be actual for at least 15 minutes.
Arbitrary heating that does not increase qualitatively and within 2 hours after 15 minutes
The discharge speed in time is 1/10 to 50 times the discharge speed after 15 minutes
And any heating within 2 hours and within 10 hours
The discharge speed in time is at least once the discharge speed after 15 minutes.
Dissolve EVOH that exhibits flow characteristics such as in the range of 2 to 50 times
It is to be subjected to melt molding. In addition, here
What is the discharge speed of the star? Nozzle 1mmφ × 10mm^LUsing
10 kg / cm^TwoThe value when the load is applied.   The discharge speed within 10 hours after 2 hours is within this time.
2 to 50 times the discharge speed after 15 minutes at least once
Yes, but within this time, as shown in Figure 1,
Those that rise are preferred. Also, the discharge speed decreases up to 15 minutes
You can do it, but the lower the rate of decrease
Well, for example, the discharge speed after 15 minutes is the same as the discharge speed at 0 minutes.
It is 1/5 or more and 1 or less, preferably 3/5 or more and 1 or less.   Using EVOH with such specific flow properties,
By melt-forming, especially with hydrophobic thermoplastic resin and
For the ethylene-based unsaturated carboxylic acid or the carboxylic anhydride
Co-extrusion or co-injection melt molding of modified thermoplastic resin by
As a result, the gel-like material does not cause interface defects such as lines and satin.
Moldings and multi-layer laminates with good appearance without stability phenomenon
Is obtained.   The EVOH composition of the present invention can be prepared, for example, by the following method.
Can be obtained.   That is, a kind of sodium and potassium acetate to EVOH
Or two kinds, and pKa (acidity index at 25 ℃) 3.5 or more at normal pressure
One or two or more acidic substances having a lower boiling point of 120 ° C or less,
And pKa3.5 or higher and acidic substance with a boiling point of 180 ° C or higher under normal pressure.
One or more, and general formula MxAly (OH)
_{2x + 3y-2Z}(A) z ・ aH_aO (M is Mg, Ca, or Zn, A is CO_Three
Or HPO_Four, x, y, z, a are positive numbers)
Obtained by containing one or more ito compounds
Can be   Here, an acidic substance with a pKa of 3.5 or more and a boiling point of 120 ° C or less under normal pressure
Examples of the quality include acetoacetic acid, formic acid, acetic acid and the like.
An acidic substance with a pKa of 3.5 or more and a boiling point of 180 ° C or more under normal pressure
As, succinic acid, adipic acid, benzoic acid, caprin
Acids, citric acid, organic acids such as lauric acid, boric acid, phosphoric acid
Inorganic acids such as potassium dihydrogen and sodium dihydrogen phosphate
Substances, aspartic acid, aminobenzoic acid, glutamic acid
Amino acids such as, but not necessarily these
It is not limited to. Of these, acidic with a boiling point of 250 ° C or higher
The substance is preferred. The hydrotalcite compound is as follows
The following is exemplified. Mg₆Al_Two(OH)₁₆CO_Three・ 4H_TwoO Mg₈Al_Two(OH)₂₀CO_Three・ 5H_TwoO Mg_FiveAl_Two(OH)₁₄CO_Three・ 4H_TwoO Mg_TenAl_Two(OH)_{twenty two}(CO_Three)₂・ 4H_TwoO Mg₆Al_Two(OH)₁₆HPO_Four・ 4H_TwoO Ca₆Al_Two(OH)₁₆CO_Three・ 4H_TwoO   As a method of adding these substances to EVOH,
The substances may be added directly to the EVOH and mixed, or
Immerse EVOH in an aqueous solution prepared by dissolving these substances in water.
You may take the operation of pickling.   Each substance in EVOH after adding these substances to EVOH
Quality content of sodium and potassium acetate
Is 0.001 to 0.05% by weight in terms of the metal, pKa
0.01 to 0.2 weight of acidic substance with a boiling point of 120 ° C or less under atmospheric pressure at 3.5 or more
%, Acidity with pKa of 3.5 or more and boiling point of 180 ° C or more under normal pressure
0.002 to 0.2% by weight of substance, preferably 0.005 to 0.1
% By weight, 0.01 to 5 for hydrotalcite compounds
%, Preferably 0.05 to 1% by weight.   The content of each substance in EVOH was measured by the following method.
You. (1) Sodium and potassium acetate   Put 100 parts of EVOH in a magnetic crucible and incinerate in an electric furnace
You. Next, dissolve the ash in 200 parts of N / 100 nitric acid aqueous solution,
The metal of the metal salt is quantified by absorption spectroscopy. (2) Acids with a pKa of 3.5 or more and a boiling point of 120 ° C or less under normal pressure
Sexual substance   The solute in EVOH is extracted with a solvent, and the acidic substance in the extract is extracted.
The quality is quantified by the neutralization titration method. Next, typical acidic substances
The quantitative method of is described below. Formic acid   Put 100 parts of EVOH and 250 parts of water in a closed container and stir at 95 ℃,
Heat for 3 hours to extract formic acid in EVOH. Then,
Use the potassium nganate solution as a titration solution to
Formic acid is quantified by a redox titration method. Acetic acid (HOAc)   Extract acetic acid in EVOH with water in the same way as for formic acid.
You. Then use an aqueous solution of sodium hydroxide as a titration solution.
First, the acetic acid in the extract is quantified by the neutralization titration method. (3) Acidic with pKa of 3.5 or higher and boiling point of 180 ° C or higher under normal pressure
material   The solute in EVOH is extracted with a solvent, and the acidic substance in the extract is extracted.
The quality is quantified by the neutralization titration method. Next, typical acidic substances
The quantitative method of is described below. Succinic acid   Extract succinic acid in EVOH with water as with formic acid
I do. Then add resorcinol and concentrated sulfuric acid to the extract.
Then, heat to 126-130 ° C, cool and quantify by colorimetric method. Adipic acid   Extract adipic acid in EVOH with water in the same way as formic acid.
Put out. Next, the extract was dried to dryness and the precipitated adipine
Dissolve the acid in water and use sodium hydroxide solution as a titration solution.
Used to quantify adipic acid in aqueous solution by neutralization titration method
I do. benzoic acid   Quantify as for adipic acid. Capric acid   Put 100 parts EVOH and 250 parts ethanol into a closed container and stir.
Heat at 80 ℃ for 5 hours to extract capric acid in EVOH
You. Then use an aqueous solution of sodium hydroxide as a titration solution.
And determine the capric acid in the extract by the neutralization titration method.
You. Lauric acid   Quantify at the same time as capric acid. citric acid   Extract citric acid in EVOH with water as with formic acid
I do. Then add acetic anhydride to the extract and heat,
Lysine is added and heated, and after cooling, quantification is performed by a colorimetric method. Boric acid   Similar to the metal analysis method described above, i.e.
Boron is quantified by absorption spectroscopy. Sodium dihydrogen phosphate   100 parts EVOH and 250 parts acetic acid aqueous solution of 1 g / concentration are sealed.
In a vessel, heat with stirring at 95 ° C for 3 hours to remove phosphoric acid in EVOH.
Extract sodium hydrogen. Then, the phosphoric acid in the extract
Ions are quantified by ion chromatography. Potassium dihydrogen phosphate   Quantify as for sodium dihydrogen phosphate. amino acid   Extraction of amino acids in EVOH with water in the same way as formic acid
I do. Then, the amino acids in the extract were analyzed by known amino acids.
Method. For example, in the case of aspartic acid, dimethy
Fumaric acid is generated by the sulfuric acid treatment, and fumaric acid is
-Quantify by larographie.   EVOH thus obtained at a temperature above the melting point,
For example, EVOH and hydrophobic thermoplastic resin are ethylenically unsaturated
Modified plasticity with carboxylic acids or their anhydrides
Co-extrusion or co-injection melt molding through resin, but EVOH
Melt viscosity changes with temperature and is included in EVOH
The effect of the above substances on the melt viscosity of EVOH depends on the temperature.
And the change in melt viscosity over time depends on the temperature.
Changes over time, so the special melt viscosity described above
The appropriate melt-forming temperature range to obtain dynamic changes
is required.   The EVOH used in the present invention is a normal EVOH, for example,
EVOH having a different ethylene content from EVOH used in the present invention,
In addition, other thermoplastics, plasticizers, and other additives
Are mixed appropriately within a range that does not impair the object of the present invention.
Then, it is free to be subjected to melt molding.   The EVOH hydrophobic thermoplastic is then melt coextruded or coextruded.
Hydrophobic thermoplastics for the production of injection-molded multilayer laminates.
The resin will be described.   First of all, as the hydrophobic thermoplastic resin, polypropylene,
Polyethylene, ethylene-propylene copolymer, ethylene
-Vinyl acetate copolymer, polyethylene terephthalate, etc.
Thermoplastic polyester, 6-nylon, 6,6-nylon
Polyamide resin, polystyrene, polyvinyl chloride, polyethylene, etc.
Polycarbonate and the like are preferred. Of these, especially preferred
The most important are polypropylene, polyethylene, and ethylene
Ropylene copolymer, thermoplastic polyester, polystyrene
It is.   Coextrusion or co-injection of EVOH and hydrophobic thermoplastic resin layer
When doing so, interlayer adhesive may be used.
As an inter-layer adhesive for bonding, ethylenically unsaturated carboxylic acid or
Or a thermoplastic resin modified with the carginic anhydride is preferred.
New The modified thermoplastic resin has an EVOH layer and a hydrophobic thermoplastic resin.
Olefin-based polymerization in consideration of the adhesiveness with the plastic resin layer
Convert ethylenically unsaturated carboxylic acid or its anhydride into the body
Logically (eg by addition reaction, graft reaction)
Modified olefin containing a carboxyl group obtained by
Polymers are preferred. Where olefin polymers
Is polyethylene (low pressure, medium pressure, high pressure), linear low density polyethylene
Polio such as polyethylene, polypropylene and polybutene
Refin, olefin and comonomer that can be copolymerized with it
(Vinyl ester, unsaturated carboxylic acid ester, etc.)
Copolymerization of ethylene-vinyl acetate copolymer, ethylene
Mean len-acrylic acid ethyl ester copolymer etc.
You. Of these, ethylene-vinyl acetate copolymer (vinyl acetate
Content of 5-55% by weight), ethylene-ethyl acrylate
Ruester copolymer (contains ethyl acrylate
Amounts of 8-35% by weight) are preferred.   With ethylenically unsaturated carboxylic acid or its anhydride,
Ethylenically unsaturated monocarboxylic acid, its ester, ethi
Lenic unsaturated dicarboxylic acid, its mono or diester
And its anhydrides, of which ethylenically unsaturated
Anhydrides of dicarboxylic acids are preferred. Specifically, Murray
Acid, fumaric acid, itaconic acid, maleic anhydride, anhydrous
Taconic acid, maleic acid monomethyl ester, maleic acid
Monoethyl ester, maleic acid diethyl ester, fluorine
Examples include maleic acid monomethyl ester.
Maleic acid is preferred.   Ethylenically unsaturated carboxylic acid or its anhydride
Addition amount or graft amount (modification degree) to the fin polymer
Is 0.01 to 15% by weight based on the olefin polymer, preferably
Is 0.02 to 10% by weight. Ethylenically unsaturated carboxylic acid
Or addition reaction of the anhydride to the olefin polymer,
The graft reaction may be carried out, for example, with a solvent (xylene, etc.), a catalyst
In the presence of (peroxide, etc.) by radical polymerization method etc.
can get. The carboxyl group thus obtained is contained.
Of Modified Polyolefin Polymer Having ASTM-D-1238-
MI measured by 65T at 190 ℃ is 0.2-30g / 10min.
Is 0.5-10g / 10 minutes. These adhesive resins alone
It may be used, or two or more kinds may be mixed and used.
it can.   Next, the method of coextrusion of EVOH and hydrophobic thermoplastic resin is
Multi-manifold merging method T-die method, feed block
Both the merge method T-die method and inflation method
Good.   The coextruded product thus obtained is further processed.
Various molded products (films, sheets,
Can be obtained). For example (1) Uniaxially molded multi-layered products (sheets, films, etc.)
Or multi-layer co-stretching by biaxial stretching and heat treatment
Sheet or film, (2) Rolling multi-layer molded products (sheets, films, etc.)
Multi-layer rolled sheet or film by (3) Vacuum the multi-layer molded product (sheet or film)
Thermoforming such as molding, pressure forming, vacuum pressure forming, etc.
Multi-layer tray, cup-shaped container, (4) Stretching from multi-layer molded products (pipes, etc.)
Obtaining bottles, cup-shaped containers, etc. by low-molding etc.
Can be. There is no particular limitation on such a secondary processing method,
Other known secondary processing methods (such as blow molding) are also adopted
it can.   The layer structure of the coextrusion laminate of the present invention is ethylene-based.
Modified thermoplasticity with unsaturated carboxylic acids or their anhydrides
If the resin is Ad and the hydrophobic thermoplastic resin is P, P ', then EVO
H / Ad / P, P / Ad / EVOH / Ad / P, P / P ′ / Ad / EVOH / Ad / P, P / Ad / E
VOH / Ad / P ′ / P, etc. are listed, and each layer is a single layer.
It may be a multi-layer or a multi-layer. Ma
EVOH, Ad blended with hydrophobic resin in the hydrophobic resin layer P '
Layers may also be used.   The coextruded laminate thus obtained has an excellent appearance.
And the gas barrier property is excellent,
Materials for vessels, such as deep-drawing containers, cup-shaped containers, bottles
It is preferably used as a material such as.   Various known co-injection methods can be used as the co-injection method.
You.   Also, as in the method known in JP-A-61-152412, three shots are taken.
Use the ejection cylinder once for a single preform mold
Resin P, / Ad, EVOH melted by the mold clamping operation are consecutive in this order
In addition, the multi-layer preform is molded by the method of injecting sequentially.
can do. The layer structure in this case is, for example, P / Ad / EVO
For example, H / Ad / P. Alternatively, it is disclosed in JP-A-60-34819.
Injection molding or injection using a co-injection nozzle
Multilayer preforms or hollow containers are molded by blow molding
You can also.   Even in these co-injection moldings, the same as in the case of co-extrusion
In addition, using conventional EVOH causes gel formation during long-term operation.
In both cases, the EVOH layer is an interlayer adhesive layer, especially ethylenic unsaturated
Carboxylic acid or carboxylic anhydride or carvone
Adhesive resin layer composed of thermoplastic resin modified with acid anhydride
Where the interfaces of the
Interfacial instability phenomenon occurs inside the preform mold)
Stains, wavy appearance defects, biting between layers, pearskin, streaks, etc.
You can't get something that has commercial value
Nonetheless, the present invention shows a special viscosity change over time.
Adjust EVOH and provide it for melt molding at an appropriate temperature
And the fact that the deterioration of the appearance can be prevented remarkably was found. this
The reason is considered to be the same as in the case of coextrusion.   Hereinafter, the present invention will be further described with reference to examples. In the example
Parts, or% are parts by weight unless otherwise specified,
Alternatively, it is shown in% by weight. F. Example Example 1   Ethylene-vinyl acetate copolymer with an ethylene content of 38 mol%
A melt consisting of 45 parts of coalescence, 50 parts of methanol and 1 part of caustic soda
Liquid at 110 ℃, 3.5kg / cm^TwoInject methanol vapor under G
For 40 minutes, the acetic acid formed during the reaction
Distilling out some of the methanol and removing it to the outside of the system.
Was. The resulting saponification reaction liquid (saponification degree of the copolymer 99.3
10% methanol from a die with a hole of 2 mm
%, Discharge into a water-methanol mixture at a temperature of 5 ° C
Solidified into lands and cut with a cutter to form pellets
I got 10 parts of ion-exchanged water for 1 part of this pellet
After washing three times with 100 parts ion-exchanged water with acetic acid 0.08
%, Benzoic acid 0.01%, sodium acetate 0.025%
It was immersed in an aqueous solution for 3 hours, drained and dried. Pellet after drying
Hydrotalcite compound Mg₆Al_Two(OH)₁₆CO_Three·Four
H_TwoDry blend O powder to pellets 0.2%
Was. Moisture contained in this pellet is 0.1%, acetic acid is 0.04
%, Benzoic acid 0.016%, sodium 0.012%
Was. In addition, the melt index of this pellet (190 ℃,
Under a load of 2160 g), the melting point was 2.5 g / 10 minutes and the melting point was 176 ° C.
Koka type flow tester (Shimadzu 301 type, nozzle 1mmφ × 10mm
^L, Load 10 kg, all the following examples have the same conditions)
The relationship between the heating time at 220 ° C and the discharge rate of this pellet was
As a result of measuring the engagement, a schematic diagram is as shown in FIG.
The discharge speed at each point in FIG. 1 is shown in Table 1.  This pellet was extruded at 220 ° C to form a film with a thickness of 20μ.
Rum was obtained (extruder: 20 mmφ, L / D = 25, die: T die, width 20)
0 mm). I ran for 150 hours continuously, during which the film
There is no generation of streaks, and gel-like particles (
A tsu refers to a small lumpy defect such as a fish.
You. ) Is 0.1 to 0.3 pcs / m^TwoAnd there is a tendency to increase over time.
It wasn't.   Furthermore, EVOH is used as an intermediate layer by using this pellet.
And maleic anhydride-modified polyethylene (maleic anhydride
Acid content 0.5wt%, vinyl acetate content 20wt%, MI 1.8g / 10
Minute) as the adhesive layer and low density polyethylene as the inner and outer layers.
The layer film was coextruded. The film composition is low density poly
Ethylene / Adhesive resin / EVOH / Adhesive resin / Low density polyethylene
Chiren {40μ / 5μ / 20μ / 5μ / 40μ (total thickness 110μ)}
Then, a film was formed under the following molding conditions.   Extruder is 60φ for EVOH, 40φ for adhesive resin, low density
For 65 degree polyethylene, use a size of 65φ
The flow method is based on the feed block method (width 600 mm). Ta
A temperature 220 ℃, chill roll 50 ℃, take-up speed 10m / min, EVOH
The resin temperature was 220 ° C. Run for 150 hours continuously
However, during that time, no streaks were generated on the film, and the EVOH layer
The number of gel-like particles that can be seen with the naked eye is 0.1 to 0.3 pieces / m^TwoOver time
However, there was no tendency to increase. The appearance of the seat is good
It was good and no wavy pattern was generated. Comparative Example 1   EVOH with ethylene content of 38 mol% and saponification degree of 99.3%
The same treatment as in Example 1 was carried out to obtain a pellet-shaped product. This Pele
10 parts of ion-exchanged water with 0.05% acetic acid concentration against 1 part of
After washing 3 times, add 0.02 adipic acid to 20 parts of deionized water.
%, Calcium acetate 0.01% each in an aqueous solution for 3 hours
After immersion, it was drained and dried. The water content in the pellets after drying is
0.1%, acetic acid 0.005%, adipic acid 0.03%, calcium
Was 0.005%.   Discharge with time using a Koka type flow tester at 200 ℃
The results of measuring the speed are shown in Table 2, and the discharge speed changes with time.
It gradually decreased to. The schematic diagram is shown in FIG.   Next, using this EVOH pellet, EVOH was used as the intermediate layer.
Polyethylene adhesive layer modified with maleic anhydride, low density poly
Use a multi-layer film with ethylene as the inner and outer layers for the die temperature and
Co-extrusion with the same equipment and conditions as in Example 1 at a resin temperature of 220 ° C.
Issued. As a result, after 20 hours, gel-like particles were generated in the EVOH layer.
Suddenly increased (Table 3), and the operation was stopped in 48 hours. EV
The wavy appearance defect in the OH layer is from the start to the end of operation.
Had occurred. Comparative Example 2   In the same manner as in Example 1, ethylene-vinyl acetate copolymer
After saponification, coagulation, cutting, washing with water, to 1 part of pellet
3 in an aqueous solution containing 0.15% acetic acid in 100 parts of deionized water
It was immersed for a time, drained and dried. Included in pellets after drying
Water content is 0.11%, acetic acid is 0.09%, calcium is 0.0005%,
Magnesium content was 0.0001% or less. Koka type floate
The discharge rate was measured with a star at 220 ° C over time.
As shown in Table 4, the discharge rate decreases with time.
I got it.   Using the same apparatus and the same film structure as in the first embodiment,
B Co-extrusion film formation at temperature and resin temperature of 220 ° C
Table 5 shows the typical situation of occurrence of spots, and the operation is stopped in 20 hours.
Stopped.  In addition, a wavy appearance defect in the EVOH layer was observed immediately after the start of operation.
, And continued until it stopped. Example 2   Ethylene content 29 mol%, Propylene content 1 mol%
Example of ethylene-propylene-vinyl acetate copolymer
Saponify, solidify, and cut in the same procedure as 1 to obtain pellets
Was. For 1 part of this pellet, 2 parts with 15 parts of ion-exchanged water
After washing twice, add acetic acid 0.03% and
Water solution containing 0.015% dipic acid and 0.015% potassium acetate
It was immersed in the liquid for 3 hours, drained, and dried. After drying on a pellet
Mg_FiveAl_Two(OH)₁₄CO_Three・ 4H_TwoO 0.3% was dry blended.
This pellet has a saponification degree of 99.4% and a melt index of 1.
2g / 10 minutes, melting point 177 ℃, water content in pellets is 0.09
%, Acetic acid 0.02%, adipic acid 0.03%, potassium 0.
It was 01%. At 230 ° C using a Koka flow tester
As a result of measuring the relationship between the heating time and the discharge speed,
The discharge speed at each point in FIG. 1 is as shown in Table 6.
I got it.   This EVOH pellet and low density polyethylene (ASTM-D1
Melt index (MI) by 238 = 1.2 g / 10 minutes, below
LDPE), and maleic anhydride as an adhesive resin.
Polyethylene (MI 1.8g / 10min (maleic anhydride modified
0.5wt%, vinyl acetate content 20wt%)}
The film is formed by inflation, and a film with a thickness of 110μ is formed.
I made it. The conditions were as follows. 1 film structure Outer layer LDPE (20μ) / Adhesive resin (10μ) / EVOH (20μ)
/ Adhesive resin (10μ) / Interlayer LDPE (50μ) (total 110
μ) 2 use device (1) LDPE 65φ extruder L / D = 22 (2) Stackable resin 40φ 〃 〃 ＝ 22 (3) EVOH 60φ 〃 〃 ＝ 22 (4) Die (3 types, 5 layers annular die) 75φ 3 molding conditions (1) 65φ extruder temperature 230 ℃ (2) 40φ 〃 220〃 (3) 60φ 〃 230〃 (4) Resin temperature 230〃   I ran for 120 hours continuously, but in the meantime
No streaky objects or wavy patterns, and few spots
The film surface was clean. Table 7 shows the occurrence of spots over time.
It is as follows. Examples 3-9   In Example 1, only treatment conditions with acid, metal salt, etc.
The EVOH pellets having the analytical values shown in Table 10, column A were obtained.
Each of them exhibited the viscosity change with time shown in Table 10, column B.
These pellets were prepared by using the same coextrusion feed block as in Example 1.
Table 10 column C shows the results of film formation using a confluent 5-layer film forming apparatus.
Shown in The appearance is good with no streaks or wavy patterns.
I got it. Control Example 3   As in Example 2, ethylene-propylene-vinyl acetate
After saponifying, coagulating, cutting, and washing with water, the copolymer
Adipic acid 0.02% in 150 parts ion-exchanged water per 1 part
It was dipped in an aqueous solution containing the solution for 3 hours, drained, and dried. After drying
Water content in pellets is 0.09%, adipic acid is 0.03%
%, Calcium 0.0007%, magnesium 0.0001% or less
I got down below. Elapsed at 230 ° C using a high-performance flow tester
Table 8 shows the results of the discharge speed measurement.
Was decreasing with time.   Same apparatus, same film structure and same forming strip as in the second embodiment
Made by co-extrusion inflation (resin temperature 230 ℃)
As a result of passing through the membrane, the number of spots generated over time increases with time
(Table 9).Control Examples 4-7   In Example 1, only treatment conditions with acid, metal salt, etc.
Change to obtain EVOH pellets with the analytical values shown in Table 11, Column A.
Was. These are the viscosity changes over time shown in Table 11 column B, respectively.
Was. These pellets were used in the same apparatus, under the same conditions and under the same conditions as in Example 1.
The results of film formation with the film configuration are shown in Table 11 column C. Example 10   The EVOH pellet obtained in Example 1 was used as an intermediate layer, an inner layer, and an outer layer.
With polyethylene terephthalate (PET), adhesive resin
And maleic anhydride modified ethylene-vinyl acetate copolymer
Multilayer sheet using the same apparatus as in Example 1 using the body
Was coextruded. The conditions were as follows. 1 sheet structure Outer layer PET / Adhesive resin / EVOH / Adhesive resin / PET inner layer = 40μ / 12μ / 80μ / 12μ / 40μ (total 184μ) 2 resin EVOH: obtained in Example 1 PET: 50% by weight phenol and 50% by weight tetrachloroethane
Intrinsic viscosity [η] dissolved in a mixed solvent of
Is 0.72 dl / g polyethylene terephthalate resin Adhesive resin: Maleic anhydride modified, ethylene-vinyl acetate
Copolymer (Acid vinyl content 24 mol%, maleic anhydride modified
1.8 wt%) 3 devices used (1) PET 65φ extruder L / D = 22 (2) Adhesive resin 40φ extruder L / D = 22 (3) EVOH 60φ extruder L / D = 28 (4) Die: 3 types 5 layers feed block type Width 600 mm 4 molding conditions (1) 65φ extruder Temperature 280 ℃ (2) 40φ extruder 220 ℃ (3) 60φ extruder 225 ℃ (4) Resin temperature 250 ℃   The product was operated for 120 hours continuously, during which streaks were generated.
There is no raw material, and gel-like material in the EVOH layer (visible to the naked eye).
0.3 to 0.6 pieces / m^TwoHowever, there is no tendency of increase over time.
The appearance was also good. Example 11   Ethylene-vinyl acetate copolymer with an ethylene content of 32 mol%
The coalescence is saponified, coagulated, cut and pelletized in the same manner as in Example 1.
The product was obtained in the form of a powder (melting point 181 ° C.). To this part 1 of the pellet
Then, after washing twice with 10 parts of ion-exchanged water, 100 parts of
Acetic acid 0.06%, benzoic acid 0.02%, potassium acetate in on-exchange water
After soaking in an aqueous solution containing 0.012% each for 4 hours
Dried. Mg on the pellet after drying₆Al_Two(OH)₁₆HPO_Four・ 4H_TwoO
Was 0.2% dry blended. This pellet has a saponification degree of 9
9.5%, melt index 1.3g / 10min, included in pellet
The water content is 0.15%, acetic acid is 0.03%, benzoic acid is 0.03%,
It was 0.01% potassium.   Using a Koka type flow tester at 250 ° C for heating time and discharge
As a result of measuring the relationship of the exit speed
Yes, the discharge speed corresponding to each point in FIG. 1 is as shown in Table 12.
I got it.   Polyethylene terephthalate resin (intrinsic viscosity [η] =
0.85dl / g, melting point 265 ℃) and EVOH resin obtained above
And vinyl acetate content 24% maleic anhydride as adhesive resin
1.1 wt% maleic anhydride modified ethylene-vinyl acetate
Nyl copolymer resin was fed to three separate extruders and extruded.
The temperature is 250 ℃ for EVOH resin and polyethylene terephthalate
Talate resin (PET) is 278 ℃, adhesive resin is 250 ℃
The resin temperature in the die is 280 ° C PET, EVOH resin
Grease and adhesive resin are allowed to join the multi-layer tubular die at 250 ° C.
Outer layer PET / Adhesive resin / EVOH / Adhesive resin / Inner layer PET = 1.0mm
/0.1mm/0.3mm/0.1mm/2.0mm pipe outer diameter 25.0mm 3 types
A five-layer pipe (thickness: 3.5 mm) was extruded.   After running for 120 hours continuously, streaks and spots are generated.
It was possible to obtain a multilayer pipe having a good appearance.   Cut the obtained multi-layer pipe to a length of 13.0 cm and seal one end.
Then, mold the neck that can be attached to the cap on the other end
Formed. Heat this multi-layer preform to 105 ° C
Then, in the mold, it is biaxially stretched by stretching the stretch rod and blowing air.
It was stretch blown and molded into a multilayer bottle having a capacity of 1. Get
The multi-layered bottle has excellent carbon dioxide barrier properties,
It was suitable as a carbonated beverage container. Control Example 8   Ethylene-vinyl acetate copolymer with an ethylene content of 32 mol%
The coalescence is saponified, coagulated, cut and pelletized in the same manner as in Example 1.
A gourd was obtained. 10 parts of ion for 1 part of this pellet
After washing twice with exchanged water, add acetic acid to 100 parts of ion-exchanged water.
Immerse in an aqueous solution containing 0.03% for 4 hours, remove the liquid, and dry.
Was. After drying, the pellets have a saponification degree of 99.5% and a melt index.
The water content in the pellet is 0.15%,
Acetic acid was 0.01%.   Using a Koka type flow tester at 250 ° C for heating time and discharge
Table 13 shows the results of measuring the relationship between the output speeds.   Polyethylene terephthalate resin (intrinsic viscosity [η] =
0.85dl / g, melting point 265 ℃) and above EVOH resin, and adhesion
Vinyl acetate content 24%, maleic anhydride content
1.1 wt% maleic anhydride modified ethylene-vinyl acetate
The copolymer resin was treated under the same conditions using the same equipment as in Example 11.
Outer layer PET / adhesive resin / EVOH / adhesive resin / inner layer PET =
Pipe outer diameter of 25 mm consisting of 1.0 mm / 0.1 mm / 0.3 mm / 0.1 mm / 2.0 mm
A three-layer, five-layer pipe (total layer thickness: 3.5 mm) was extruded. Start operation
3 hours after the beginning, streaks start to form, and with time
The situation was severe and the operation was stopped after 6 hours. Got
Make a multi-layer preform from a pipe and blow mold it 1
The bottle that has a good appearance due to the streak
I couldn't get it. Example 12   Ethylene-vinyl acetate copolymer with an ethylene content of 32 mol%
The coalescence was carried out in the same manner as in Example 1 by using the following dried petretette (melt
181 ° C.) was obtained. Saponification degree 99.4% Melt index 4.8g / 10 minutes Acetic acid content 0.02% Benzoic acid 〃 0.02% Sodium〃 0.006% Mg₆Al_Two(OH)₁₆CO_Three・ 4H_TwoO 0.15%   Heating time and discharge at 260 ° C using a Koka flow tester.
The result of measuring the relationship of the exit speed is as shown in the schematic diagram 1
The discharge speeds corresponding to each point in Fig. 1 are shown in Table 14.
Was.   Intrinsic viscosity [η] = 0.73dl / g, PET with a melting point of 258 ° C
EVOH and maleic anhydride modified as adhesive resin (Ad)
Ethylene-vinyl acetate resin (melt index 4.0g / 1
0 minutes, vinyl acetate content 24wt%, maleic anhydride modification degree
1.1 wt%) with three injection cylinders and a single
PET / Ad / E using co-injection equipment with ref-form die
VOH / Ad / PET ＝ 1.0mm / 0.1mm / 0.3mm / 0.1mm / 2.0mm
3 types 5 layers preform (outer diameter 25mm length)
130mm) was made by co-injection molding.   After operating continuously for 120 hours, it may generate streaks, lumps, etc.
A preform with good appearance was obtained with no raw material.   This preform is heated to 105 ° C and stretched in a mold.
By biaxial stretching blow by stretching and blowing air.
A quantity 1 outer layer bottle was molded. The resulting multi-layer bottle
Has excellent carbon dioxide gas barrier property and oxygen barrier property.
It was suitable as various beverage containers. Control Example 9   EVOH as shown below was obtained.   Ethylene content 32 mol%      Saponification degree 99.3% Melt index 4.8g / 10 minutes     Acetic acid content 0.01%   Heating time and discharge at 260 ° C using a Koka flow tester.
Table 15 shows the results of measuring the relationship between the output speeds.   Same as Example 12 except that the above resin was used as EVOH.
Multi-layer preform was co-injection molded with the equipment and conditions,
There are more streaky objects than 4 hours after molding and this is biaxially stretched.
Because of the low-strength molded bottle of volume 1
Only the one with a bad appearance was obtained. Control Example 10   In Example 1, the pellet was added to deionized water with acetic acid,
3 hours in an aqueous solution containing benzoic acid and sodium acetate
Instead of soaking, pellets in ion-exchanged water for 3 hours
The pellets were dipped and the pellets were obtained in the same manner as in Example 1.   The pellets were treated at 220 ° C. in the same manner as in Example 1.
The relationship between the heating time and the discharge rate was measured. The results are shown in Table 16.
Show.  Also, using the pellets under the same conditions as in Example 1.
Co-extrusion and continuous operation were performed to obtain a multilayer film. Profit
Table 17 shows the occurrence of gel-like particles in the obtained film.
Table 17 shows the gel-like particles of the multilayer film obtained in Example 1.
The occurrence status of is also shown. Control Example 11   Described in Example 1 of JP-A-61-95053
EVOH was obtained in a similar manner. Acetic acid in the EVOH obtained
Sodium content is 0.036% by weight, acetic acid content is 0.123
%, Sodium hydrogen succinate content is 0.048% by weight
Was. This EVOH was heated at 210 ° C in the same manner as in Example 1.
The relationship between the heating time and the discharge rate was measured. The results are shown in Table 18.
Show.   In addition, using this EVOH under the same conditions as in Example 1,
Extrusion and continuous operation were carried out to obtain a multilayer film. Get
Table 19 shows the occurrence of gel-like spots on the film. G. Effects of the Invention   According to the EVOH composition of the present invention, a composition having an extremely good appearance is obtained.
It is possible to obtain a shaped article, especially a multi-layer laminate, and
During the subsequent melt molding, the appearance deteriorates over time.
, Always obtaining a molded product with a good appearance, especially a multilayer laminate.
Can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the results of measuring the relationship between the heating time and the discharge speed using a Koka type flow tester. The position of each point in the figure is: A point: 15 minutes later C point: 2 hours later B point: 1.5 hours later (point at which the discharge speed is the lowest between A and C) D point: 5 hours later

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Yukio Oizumi               1621 Sazu, Kurashiki City, Okayama Prefecture               Inside the rale                    Examiner Hideji Sasaki                (56) References JP-A-61-95053 (JP, A)                 JP-A-62-15246 (JP, A)                 JP-A-60-199040 (JP, A)

Claims (1)

(57) [Claims] Ethylene content of 20 to 60 mol%, saponification degree of vinyl acetate component 95% or more of ethylene-vinyl alcohol copolymer, sodium acetate, 0.001 to 0.05% by weight of potassium acetate converted to the metal, pKa (Acidity index at 25 ° C) 0.002 to 0.2% by weight of acidic substance having a boiling point of 180 ° C or higher at atmospheric pressure at 3.5 or higher, 0.01 to 0.2% by weight of acidic substance having a boiling point of 120 ° C or lower at atmospheric pressure at pKa3.5 or higher, and General formula MxAly (OH)
_{2x + 3y-2Z} (A) z ・ aH _a O (M is Mg, Ca, or Zn, A is CO ₃
Or a composition containing 0.01 to 5% by weight of a hydrotalcite compound represented by HPO ₄ , x, y, z, and a) and having a melting point of the ethylene-vinyl alcohol-based copolymer.
In the relationship between the heating time and the discharge rate in the high flow tester at at least one point of 10 to 80 ° C. higher, the composition showed that the discharge rate did not substantially increase until at least 15 minutes, and The discharge speed at any heating time within 2 hours after 1 minute is in the range of 1/10 to 50 times the discharge speed after 15 minutes, and at any heating time within 10 hours after 2 hours. Discharge speed of 2 after at least 15 minutes once 2
An ethylene-vinyl alcohol-based copolymer composition having a flow characteristic within a range of up to 50 times. 2. Ethylene-vinyl alcohol copolymer composition,
2. The ethylene-vinyl alcohol copolymer composition according to claim 1, wherein the flow rate after 15 minutes has a flow characteristic of 1/5 to 1 of the discharge rate at 0 minutes. 3. Ethylene-vinyl alcohol copolymer composition,
The ethylene-vinyl alcohol-based copolymer composition according to claim 1, which exhibits flow characteristics in which the discharge rate within 2 hours and within 10 hours increases with the passage of time within this time.