JPH09165483A - Resin composition - Google Patents

Abstract

(57) [Abstract] [Problem] Transparency and gas barrier property (oxygen permeation resistance,
To provide a resin composition having excellent carbon dioxide permeation resistance and the like). SOLUTION: The ethylene-vinyl alcohol copolymer (A) having an ethylene content of 20 to 60 mol% is added to a boron compound, a peroxide, a polyvalent acid, a polyvalent amide compound, a copper compound, an aluminum compound, HCT (Half Cryst) obtained by reacting at least one compound selected from titanium compounds, zinc compounds, tin compounds, vanadium compounds, and chromium compounds, and obtained by a differential scanning calorimeter
A resin composition having an alization time of 230 seconds or more.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) resin composition, and more specifically to transparency, gas barrier properties (oxygen permeation resistance, oxidation resistance). The present invention relates to an EVOH resin composition having excellent carbon permeability.

[0002]

2. Description of the Related Art Generally, EVOH is a resin which is excellent in transparency, gas barrier property, aroma retaining property, solvent resistance, oil resistance and the like when formed into a film, and it is utilized in various fields by utilizing this characteristic. ing. In particular, with respect to transparency, various studies have been conducted for the purpose of improving the transparency.
There are methods such as performing a rapid cooling operation in the H film formation process and using EVOH having a low saponification degree. On the other hand, E
For the purpose of improving the impact resistance of VOH, JP-A-57-
34148, JP-A-57-59940 and the like propose that EVOH contains an alcohol plasticizer and boric acid or borate.

[0003]

However, it is difficult to satisfy both transparency and gas barrier property, and EV
As described above, in order to increase the transparency of the OH film, it is necessary to perform the quenching operation in the film forming process, but the quenching operation lowers the crystallinity and accordingly the gas barrier property. . Further, when EVOH having a low degree of saponification is used, the gas barrier property will be deteriorated.

Further, in the technologies disclosed in JP-A-57-34148 and JP-A-57-59940, impact resistance is examined, but transparency and gas barrier property are not considered at all. As a result of a detailed study by the present inventors, it is difficult to obtain one having both excellent transparency and gas barrier property, and further improvement is desired with the recent advancement of technology. Under the circumstances, the present invention provides a resin composition that solves the above problems, that is, has excellent transparency and gas barrier properties, and further has not only general gas barrier properties against oxygen but also gas barrier properties against carbon dioxide. It is also an object of the present invention to provide an excellent resin composition.

[0005]

[Means for Solving the Problem] However, as a result of intensive studies to solve such a problem, the present inventors have found that EVOH (A) having an ethylene content of 20 to 60 mol% contains a boron compound and a peroxide compound. At least one compound selected from oxides, polyhydric acids, polyhydric amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, tin compounds, vanadium compounds, and chromium compounds is reacted, and HCT ( Half Crystalization Time) is 23
The present invention has been completed by finding that a resin composition of 0 seconds or more solves such a problem. However, HCT is 1 from the melting point of the ethylene-vinyl alcohol copolymer (A).
It is the time (seconds) to divide the peak area obtained by the differential scanning calorimeter into two equal parts at a low temperature of 2 ° C. In the measurement with the differential scanning calorimeter, the composition is first heated to 230 ° C at 10 ° C / min. And hold for 5 minutes, then EVOH
It is performed by cooling at a temperature of 80 ° C./min to a temperature 12 ° C. lower than the melting point of (A) and holding at that temperature.

More detailed description will be given with reference to FIG.
Is the isothermal crystallization curve (vertical axis; specific heat (J / g · ° C.), horizontal axis; time (seconds)) of a typical example of the resin composition of the present invention (not limited to this), and HCT Is a point at which the peak of the crystallization curve begins to fall, b is the end point of the peak, and S is the area surrounded by the straight line ab and the peak (curves a to b). It is the time c (seconds) that intersects the horizontal axis when the vertical axis is drawn so as to be divided in half.

In the present invention, the boron-based compound, the peroxide, the polyvalent acid, the polyvalent amine-based compound, the copper compound, the EVOH (A) solvent content of 0.1 to 70% by weight, Aluminum compound, titanium compound, zinc compound,
When at least one compound selected from tin compounds, vanadium compounds and chromium compounds is reacted, the effect of the present invention is remarkably exhibited. In addition, in the present invention, the resin composition may further have an EV having a melting point difference of 15 ° C. or less.
By blending OH (B), a resin composition having an excellent gas barrier property against oxygen and carbon dioxide can be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The EVOH (A) of the present invention has an ethylene content of 20.
-60 mol%, preferably 23-58 mol%, and more preferably 25-55 mol% are not particularly limited. If the ethylene content is less than 20 mol%, the melt moldability tends to be poor, and if it exceeds 60 mol%, the gas barrier property tends to deteriorate. The degree of saponification is not particularly limited, but 70 to 100 mol%, preferably 80 to 100 mol% is preferable. Also, melt index (210 ℃,
For load 2160g) 0.1-80g / 10 minutes,
It is preferably 1 to 70 g / 10 minutes.

The compounds reacted with EVOH (A) are boron compounds, peroxides, polyvalent acids, polyvalent amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, tin compounds, vanadium. Compounds, at least one compound selected from chromium compounds, examples of boron compounds include boric acid, borate, borax, and the like, and examples of peroxides include formic acid, peracetic acid, and perbenzoic acid. As the polyacid, malonic acid, succinic acid, maleic acid, fumaric acid, adipic acid, sebacic acid,
Phthalic acid, isophthalic acid, terephthalic acid, itaconic acid,
Trimellitic acid, pyromellitic acid and the like, and the polyvalent amine compounds include methylenediamine, ethylenediamine, trimethylenediamine, tetramethylenediamine,
Examples include pentamethylenediamine, hexamethylenediamine, phenylenediamine, benzine, diaminostilbene and tolidine. Further, as the copper compound, the aluminum compound, the titanium compound, the zinc compound, the tin compound, the vanadium compound, and the chromium compound, any compounds can be adopted, and specifically, copper sulfate, titanisulfite, α
-Titanic acid, ammonium vanadate and the like can be mentioned. Among the above, a boron compound, particularly boric acid, is preferably used.

In the present invention, EVOH (A) is used as described above.
Is reacted with at least one compound selected from boron compounds, peroxides, polyvalent acids, polyvalent amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, tin compounds, vanadium compounds and chromium compounds. However, the HCT is 230 seconds or more, preferably 235 to 900 seconds, more preferably 240 to 60.
It needs to be 0 seconds, and this is the most important feature of the present invention. If the HCT is less than 230 seconds, a film having sufficient gas barrier properties and transparency cannot be obtained, which is not preferable.

As a method for obtaining the resin composition having an HCT of 230 seconds or more in the present invention, a method of increasing the degree of polymerization of EVOH, a method of branching the main chain, a method of irradiating with radiation or an electron beam, etc. are also possible. However, the following method is particularly preferable.
That is, the solvent content of EVOH (A) is 0.1 to 70% by weight, preferably 0.3 to 65% by weight, more preferably 0.5 to 60% by weight, and the boron compound and the peroxide. Most preferably, at least one compound selected from the group consisting of polyvalent acids, polyvalent amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, tin compounds, vanadium compounds and chromium compounds is reacted.
If the solvent content is less than 0.1% by weight, the reaction will be insufficient and non-uniform, and the effects of the present invention will not be exerted remarkably. On the other hand, if it exceeds 70% by weight, it will take a long time to dry the resin. It will not be economical.

The method for controlling the solvent content of the EVOH (A) within the above range is not particularly limited, and, for example, the EVOH pellets may be dipped in a solvent such as water or alcohol and controlled by the immersion time. There are methods such as controlling by the drying process.

A boron compound is added to the EVOH (A).
Examples of the method of reacting at least one compound selected from peroxides, polyvalent acids, polyvalent amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, tin compounds, vanadium compounds, and chromium compounds include EVOH by dissolving the compound in a solvent such as water or alcohol
Mix with (A) or add EVOH (A) to the solution of the compound.
However, the method is not limited to this. For example, the method of immersing EVOH (A) and reacting the compound with EVOH (A) in an extruder can be used.

Boron compounds, peroxides, polyhydric acids, polyhydric amine compounds, copper compounds, aluminum compounds, titanium compounds, zinc compounds, which are reacted with EVOH (A),
EVOH is the amount of at least one compound selected from tin compounds, vanadium compounds, and chromium compounds.
1 to 10,000 ppm, preferably 5 to (A)
9000 ppm, more preferably 10-8000 ppm
It is. If the amount is less than 1 ppm, the transparency is not preferable, and if it exceeds 10,000 ppm, the melt viscosity of the resin becomes too high and the film-forming property is deteriorated, which is not preferable.

The resin composition (C) thus obtained is a composition from which a film or sheet having both excellent transparency and gas barrier properties can be obtained, and the resin composition (C) alone can be used in the present invention. Although the object is sufficiently satisfied, in the present invention, the resin composition (C) further comprises
EVOH (B) whose difference from the melting point of (A) is within 15 ° C
By blending, a resin composition having a more excellent gas barrier property can be obtained.

The EVOH (B) is not particularly limited as long as the difference in melting point from the EVOH (A) is within 15 ° C., but the ethylene content is 20 to 60 mol%, preferably 25 to 55 mol%. , The saponification degree is 70 to 100 mol%, preferably 80 to 100 mol%, and the melt index (2
10 ° C., load 2160 g) is 0.1 to 80 g / 10 minutes,
Preferably 0.5 to 70 g / 10 minutes is used.

The compounding ratio of the resin composition (C) and EVOH (B) is 1/99 to 75/25, preferably 5/95 to 6
It is 5/35, more preferably 10/90 to 50/50. When the blending ratio is less than 1/99, crystallization of EVOH (B) becomes dominant and the transparency is lowered, and when it exceeds 75/25, the barrier property is not improved and the effect of the present invention is not remarkably exhibited. .

The mixing method is not particularly limited, and EV
OH (B) and the resin composition (C) are dissolved in a water-alcohol solvent and mixed, EVOH (B) or the resin composition (C) is dissolved in a water-alcohol solvent and mixed with the other, Alternatively, a method of melt-mixing EVOH (B) and the resin composition (C) may be mentioned, and usually a method of melt-mixing is adopted. For example, a method in which EVOH (B) and the resin composition (C) are dry-blended and then melted and blended, a method in which the EVOH (B) and the resin composition (C) are blended in a molten state, or EVOH (B) or Examples include a method in which the resin composition (C) is melted and then the other is added in a dry state. Above all, EVOH
The method of dry-blending (B) and the resin composition (C) and then melting and blending is practical in view of the simplicity of the apparatus, the cost of the blended product, and the like.

Further, in the present invention, if necessary, a plasticizer,
It is also possible to use additives such as heat stabilizers, ultraviolet absorbers, antioxidants, colorants, antistatic agents, lubricants, fillers, fillers and other resins. In particular, hydrotalcite-based compounds, hindered phenol-based, hindered amine-based heat stabilizers, and metal salts of higher aliphatic carboxylic acids can also be added as gel generation inhibitors.

Thus, the resin composition of the present invention (the resin composition (C) or a blend of the resin composition (C) and EVOH (B)) is often used for molded articles, and pellets, films and sheets are prepared by melt-kneading. , Container, fiber, rod, tube,
It is molded into various molded products. In many cases, melt-molding is performed again using these crushed products (when reusing recovered products) or pellets.

As the melt molding method, an extrusion molding method such as a T-die extrusion method, an inflation extrusion method, a blow molding method, a melt spinning method, a profile extrusion method, or an injection molding method is mainly employed. Among them, the T-die extrusion method and the inflation extrusion method are preferably used for forming a film of the resin composition of the present invention.

In particular, in the present invention, when the film is formed by the T-die extrusion method, the cooling roll temperature of the extruder can be controlled between the glass transition temperature (Tg) and the melting point (Tm) of the resin composition. preferable. When the film is formed by the inflation extrusion method, the air-cooled inflation method can be used. That is, a water-cooled inflation method is usually used to increase transparency, but this reduces the gas barrier property, whereas the resin composition of the present invention uses an air-cooled inflation method that does not require a quenching operation. Even if used, a film having excellent transparency can be obtained without lowering the gas barrier property, which is preferable.

Thus, the film and the like obtained by the above method are excellent in both transparency and gas barrier property, and are very effective for applications such as food packaging materials. Especially, transparency and gas barrier property against carbon dioxide are also good. Therefore, photosynthesis of plants is promoted, and if this is taken into consideration, it is very useful as an agricultural film.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified. Example 1 Production of resin composition (C) Ethylene content 38 mol%, saponification degree 99.5 mol%,
Melt index (MI) 25g / 10 minutes (210
6 pellets of EVOH (A) at 6 ° C and a load of 2160 g)
With the solvent content kept at 40% by immersing in water at 0 ° C, it is put into a 1% aqueous solution of boric acid and kept at 80 ° C for 1 hour.
Stirred for 2 hours (150% boric acid against EVOH (A))
0 ppm included). Then, wash with pure water at 20 ° C.
It was dried at 0 ° C. for 8 hours to obtain the resin composition (C) of the present invention. The HCT of the resin composition (C) was 480 seconds. HCT was measured at a temperature 12 ° C. lower than the melting point of EVOH (A), that is, at 161 ° C. using a differential scanning calorimeter (DSC7 manufactured by Perkinermer).

The resin composition (C) was supplied to a single-screw extruder equipped with a T-die, and a film having a thickness of 30 μm was produced by the T-die extrusion method under the following film forming conditions.

The obtained film was evaluated for transparency and gas barrier property (oxygen permeability, carbon dioxide permeability) as follows. (Transparency) Murakami Color Research Laboratory RM
The haze value of the film was measured using -15A.

(Gas Barrier Property) Oxygen Permeability The oxygen permeability of the film can be measured by MODERN-CONTROL.
OX-TRAN10-50 manufactured by OL Co., Ltd., 20 ° C., 6
It was measured under the condition of 5% RH (cc · 20 μm / m ² ·
day · MPa). Carbon dioxide permeability 2 The carbon dioxide permeability of the film was measured using a Yanagimoto gas permeation measuring device (Yanamoto Manufacturing Co., Ltd .: GTR-30XN).
It was measured under conditions of 0 ° C. and 0% RH (cc · 20 μm /
m ² · day · MPa). The measurement conditions are as follows. Column: 60/80 mesh Activated carbon packed length 150 cm Column temperature: 80 ° C Inlet temperature: 150 ° C Carrier gas: Helium

Examples 2 to 6 and Comparative Examples 1 to 4 EVOH (A) shown in Table 1 and additives were used to obtain a resin composition (C) according to Example 1 (HCT is shown in Table 1). As shown). With respect to the resin composition (C), a film was produced according to Example 1, and each physical property was evaluated in the same manner as in Example 1. In addition, in Example 6 and Comparative Example 4, the film was formed by setting the cooling roll temperature at 20 ° C. and increasing the cooling rate.

Example 7 Using the resin composition (C) of Example 1, an inflation film was formed under the following film forming conditions. (Film forming conditions) Extruder 40 mm diameter extruder Screw length (L) / diameter (D) 28 die Center of die diameter 100 mm, die gap 1.5 mm Spiral die Fold width 350 mm Extrusion temperature Cylinder tip 220 ° C. Die 210 ° C. Resin 214 ° C. Screw rotation speed 40 rpm Discharge amount 15 kg / hr Airing air temperature 20 ° C. Film temperature 35 ° C. (immediately before passing through nip rolls) The obtained film was evaluated for transparency and gas barrier property (oxygen permeability, carbon dioxide permeability). Evaluation was performed in the same manner as in Example 1.

Example 8 Using the resin composition of Example 2, a film was prepared according to Example 7, and each physical property was evaluated in the same manner as in Example 1.

Example 9 Using the resin composition of Example 3, a film was prepared according to Example 7, and each physical property was evaluated in the same manner as in Example 1.

Comparative Example 5 Using the resin composition of Comparative Example 2, a film was prepared according to Example 7, and each physical property was evaluated in the same manner as in Example 1.

Comparative Example 6 Using the resin composition of Comparative Example 3, a film was produced according to Example 7, and each physical property was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results of Examples 1 to 9 and Comparative Examples 1 to 5.
Shown in

[0034]

[Table 1] Resin composition (C) EVOH (A) additive Content HCT Et Sv MI (ppm) (sec) Example 1 38 99.6 25 Boric acid 1500 480 〃 2 38 99.6 25 Boric acid 660 270 〃 3 38 99.6 25 Boric acid 100 250 〃 4 38 99.6 25 Copper sulphate 1400 470 〃 5 38 99.6 25 Copper sulphate 500 280 〃 6 38 99.6 25 Boric acid 1500 480 Comparative example 1 38 99.6 25 −−− − − 200 〃 2 38 99.6 25 Boric acid 20 210 〃 3 38 99.7 1 −−− −− 300 〃 4 38 99.6 25 −−−−− 200

Note) Et: ethylene content (mol%) Sv: degree of saponification (mol%) MI: melt index (g / 10 minutes) (210 ° C.,
Load 2160 g) The content of the additive was determined by the atomic absorption method.

[0036]

[Table 2] Transparency Oxygen permeability Carbon dioxide permeability (cm ³ · 20 μm / m ² · day · MPa) (cm ³ · 20 μm / m ² · day · MPa) Example 1 1.2 7.2 13 13 〃 2 1.3 7.1 13 〃 3 1.2 7.1 7.1 13 〃 4 1.3 7.2 7.2 12 〃 5 1.2 7.1 7.1 12 〃 6 1.1 9.0 9.0 15 〃 7 1.3 7 1 13 〃 8 1.5 7.2 12 〃 9 1.6 1.6 7.1 12 Comparative Example 1 3.2 7.0 15 〃 2 3.0 7.0 16 〃 3 2.8 7.0 14 〃 4 1.1 18 25 〃 5 3.1 7.1 7.1 14 〃 6 3.0 6.9 913

In Examples 7, 8 and 9, the resin compositions of Examples 1, 2 and 3 were used, and in Comparative Examples 5 and 6, the resin compositions of Comparative Examples 2 and 3 were used.

Example 10 Resin composition (C) of Example 1 and ethylene content 32 mol%, saponification degree 99.5 mol%, MI 3 g / 10 min (21
EVOH (B) (EVOH at 0 ° C, load 2160g)
(The difference in melting point from (A) is 10 ° C.), and the mixture is fed to a twin-screw extruder to prepare pellets.
A film was produced by a die extrusion method. Resin composition (C)
The blending ratio of EVOH (B) is 25/75. The obtained film was evaluated for transparency and gas barrier property in the same manner as in Example 1.

Examples 11 to 14 Using the resin composition (C) and EVOH (B) as shown in Table 3, a mixture was obtained according to Example 10. With respect to the mixture, a film was produced according to Example 10, and each physical property was evaluated in the same manner as in Example 1. The results of Examples 10 to 14 are shown in Table 4.

[0040]

[Table 3] Resin composition (C) EVOH (B) blending ratio Et Sv MI (C) / (B) Example 10 Resin composition of Example 1 32 99.6 3 25/75 〃 11 Resin composition of Example 2 32 99.6 3 50/50 〃 12 Resin composition of Example 3 32 99.6 3 10/90 〃 13 Resin composition of Example 4 32 99.6 3 25/75 〃 14 Resin composition of Example 5 32 99.6 3 50 / 50

[0041]

[Table 4] Transparency Oxygen permeability Carbon dioxide permeability (cm ³ · 20 μm / m ² · day · MPa) (cm ³ · 20 μm / m ² · day · MPa) Example 10 1.3 5.5 5.5 8 〃 11 1.4 6.1 8.1 〃 12 1.4 5.0 6.3 〃 13 1.3 5.4 7.0 7.0 〃 14 1.5 5.1 8.3

[0042]

The resin composition of the present invention is EVOH (A)
Boron compounds, peroxides, polyvalent acids, polyvalent amine compounds, copper compounds, aluminum compounds, titanium compounds,
Specific HCT obtained by reacting at least one compound selected from a zinc compound, a tin compound, a vanadium compound and a chromium compound, and measured by a differential scanning calorimeter
Is excellent in both transparency and gas barrier properties, and the melting point of EVOH is within 15 ° C.
By blending (B), the gas barrier property is particularly improved, and it is very useful for applications such as packaging materials and agricultural film applications. Further, the resin composition of the present invention does not need to be rapidly cooled at the time of film formation, and has excellent film formability.

[Brief description of the drawings]

FIG. 1 isotherm crystallization curve measured by a differential scanning calorimeter in the resin composition of the present invention.

[Explanation of symbols]

a: the start point of the peak of the isothermal crystallization curve b: the end point of the peak of the isothermal crystallization curve S: the area surrounded by the straight line ab and the peak (curves a to b) c: the area S is divided in half Point intersecting the horizontal axis when the vertical axis is drawn

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 18, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

More detailed description will be given with reference to FIG.
Is an isothermal crystallization curve (vertical axis; heat flow rate (mW) , horizontal axis; time (seconds)) of a typical example of the resin composition of the present invention (not limited to this), and HCT is Let a be the starting point of the peak of the crystallization curve, b be the end point of the peak, and let S be the area enclosed by the straight line ab and the peak (curves ab).
In this case, when the vertical axis is drawn so as to divide the area S in half, the time c (second) intersects with the horizontal axis.

[Procedure amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction contents]

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified. Example 1 Production of resin composition (C) Ethylene content 38 mol%, saponification degree 99.5 mol%,
Melt index (MI) 25g / 10 minutes (210
8 ° C EVOH (A) powder at 2160g)
With the solvent content kept at 40% by immersing in water at 0 ° C , it is put into a 1% aqueous solution of boric acid and kept at 80 ° C for 1 hour.
Stirred for 2 hours (150% boric acid against EVOH (A))
0 ppm included). Then, wash with pure water at 20 ° C.
It was dried at 0 ° C. for 8 hours to obtain the resin composition (C) of the present invention. The HCT of the resin composition (C) was 480 seconds. HCT was measured at a temperature 12 ° C. lower than the melting point of EVOH (A), that is, at 161 ° C. using a differential scanning calorimeter (DSC7 manufactured by Perkinermer).

[Procedure 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (3)

[Claims] 1. A boron-based compound, a peroxide, a polyvalent acid, a polyvalent amine-based compound, a copper compound, an aluminum compound in an ethylene-vinyl alcohol-based copolymer (A) having an ethylene content of 20 to 60 mol%. , A titanium compound, a zinc compound, a tin compound, a vanadium compound, a chromium compound, at least one compound selected from the reaction, and HCT (Half Crystalization Time) is 230 seconds or more, a resin composition characterized by . However, HCT is the time (seconds) that divides the peak area obtained by a differential scanning calorimeter into two equal parts at a temperature 12 ° C. lower than the melting point of the ethylene-vinyl alcohol copolymer (A). 2. A boron compound, a peroxide, a polyvalent acid, and a polyvalent amine compound in a state where the solvent content of the ethylene-vinyl alcohol copolymer (A) is 0.1 to 70% by weight. The resin composition according to claim 1, which is obtained by reacting at least one compound selected from a copper compound, an aluminum compound, a titanium compound, a zinc compound, a tin compound, a vanadium compound, and a chromium compound. 3. An ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20 to 60 mol% and having a difference in melting point (Tm) of not more than 15 ° C. is further blended. Item 1. The resin composition according to Item 1 or 2.