JP2001114966A - Resin composition and its production and use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which is excellent in barrier properties against various substances represented by an oxygen gas, water vapor, etc., especially barrier properties under a high humidity, and exhibits a stable performance. SOLUTION: This resin composition is prepared by compounding 100 pts.wt. saponified vinyl acetate polymer resin with 0.01-20 pts.wt. swellable fluoromica mineral.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saponified vinyl acetate polymer comprising a saponified vinyl acetate polymer (hereinafter sometimes abbreviated as PVOH) resin and a specific fluoromica-based mineral and having excellent barrier properties. The present invention relates to a resin composition, a production method and a use thereof.

[0002]

2. Description of the Related Art The functions required of packaging materials are diverse, but the barrier properties against various gases for protecting the contents (gas barrier properties) are important properties that affect the preservability of foods. Due to the diversification of packaging technology, regulation of additives, changes in taste, etc., gas barrier properties have become one of the more important properties. Oxygen, light, heat, moisture and the like can be cited as the alteration factors of foods, and oxygen is a main alteration factor of foods. In addition, barrier materials that have barrier functions not only for oxygen gas but also for various gases, organic solvent vapors, aromas, etc. are effective in preventing rust, odor and sublimation, and can be used in confectionery bags, skipjackets, retort pouches, carbon dioxide beverages It is used in many fields such as foods such as containers, cosmetics, agricultural chemicals, and medical treatment. However, generally, the gas barrier properties of the resin are low, and the performance as a barrier material used for the above purpose is not sufficient. On the other hand, for the purpose of improving the gas barrier properties of the resin, a technique of dispersing a filler, particularly a layered inorganic compound, in the resin is widely known,
For example, JP-A-64-43554 describes a method in which mica and talc are dispersed in a saponified ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVOH). However, the resin composition obtained by such a method has a drawback that the dispersibility of the inorganic layered compound in the resin is poor, and the transparency of the resin is significantly deteriorated. To overcome this drawback, various attempts have been made to use dispersion media, especially inorganic layered compounds which swell or cleave in water. Such an inorganic layered compound is typified by a layered silicate. When compounding this with a polyamide, the inorganic layered compound is dispersed in a monomer as shown in JP-A-62-74957. After the polymerization, or when compounding with EVOH, JP-A-5-39392, JP-A-5-86241,
As disclosed in JP-A-6-57066, a method is disclosed in which an inorganic layered compound is swelled and cleaved in an aqueous solvent (water-methanol solvent) and dispersed in EVOH. However, the method of polymerizing after dispersing the inorganic layered compound in the polyamide monomer is extremely excellent in that a good dispersion is obtained.On the other hand, the viscosity is significantly increased due to the dispersion of the inorganic layered compound. What can be produced is only those containing an extremely low concentration of an inorganic layered compound.Since the barrier properties of the main component polyamide itself are not so excellent, even if the inorganic layered compound is dispersed, for example, compared to EVOH alone However, there are problems such as poor barrier properties. In addition, EV was obtained in a state where the inorganic layered compound was swollen and cleaved in an aqueous solvent.
Regarding the method of dispersing in OH, there is a problem that it is very difficult to ensure sufficient dispersibility with conventionally used montmorillonite and the like, and it is difficult to exhibit stable performance. Further, apart from these, higher gas barrier materials are always desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and provides a resin composition exhibiting remarkably excellent barrier properties, particularly in a high-humidity environment, and having stable performance.
It is an object of the present invention to provide a method for easily producing the resin composition and a film using the resin composition.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve such problems, and as a result, surprisingly, the combination of a PVOH-based resin and a specific fluoromica-based mineral is extremely low. The present inventors have found that they show excellent performance and that the objects of the present invention can be more effectively achieved by using a specific production method.

That is, the first invention of the present invention is a PVO
It is a resin composition having 0.01 to 200 parts by weight of a swellable fluoromica-based mineral with respect to 100 parts by weight of an H-based resin.

According to a second aspect of the present invention, a solution of a PVOH-based resin and a dispersion of a swellable fluoromica compound are separately prepared in advance, and then mixed and dried to remove the solvent. This is a method for producing a resin composition.

Further, a third invention of the present invention is a film comprising the above resin composition, and a multilayer film having at least one layer comprising the above resin composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The swellable fluoromica-based mineral used in the present invention,
Typically, a material obtained by subjecting talc to a heat treatment of a mixture of sodium and / or lithium silicofluoride or fluoride may be used. As a specific method, there is, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2-149415. That is, this method uses talc as a starting material, and intercalates sodium ions and / or lithium ions into the starting material to obtain a swellable fluoromica-based mineral. In this method, talc is mixed with silicofluoride and / or fluoride, and is mixed in a magnetic crucible for about 700 to
By carrying out heat treatment at 1200 ° C. for a short time, a fluoromica-based mineral can be obtained. The swellable fluoromica-based mineral used in the present invention is particularly preferably produced by this method.

In order to obtain a swellable fluoromica-based mineral, it is necessary that the metal constituting the silicide or fluoride is sodium or lithium among alkali metals. These alkali metals may be used alone or in combination. Of the alkali metals, potassium is not preferable because swellable fluorine mica-based mica cannot be obtained, but is used in combination with sodium or lithium, and is used for the purpose of adjusting the swellability if the amount is limited. Is also possible. The amount of silicofluoride and / or fluoride mixed with talc is 10% of the whole mixture.
The range of from about 35% by weight to 35% by weight is preferable, and if it is out of this range, the production rate of the swellable fluoromica-based mineral decreases.

The swellable fluoromica-based mineral used in the present invention is typically represented by the following formula.

Α (MF) · β (aMgF ₂ · bMgO) · γSiO ₂

Here, M represents sodium or lithium, α, β, γ, a and b each represent a coefficient,
0.1 ≦ α ≦ 2, 2 ≦ β ≦ 3.5, 3 ≦ γ ≦ 4, 0 ≦ a
≦ 1, 0 ≦ b ≦ 1, a + b = 1.

The swelling property in the present invention means that the fluoromica-based mineral absorbs polar molecules such as carboxylic acids, alcohols, and water molecules between the layers, thereby increasing the interlayer distance or further swelling cleavage, and Fluorine mica-based mineral represented by the above formula means a property of forming fine particles, and exhibits such a swelling property.

The swellable fluoromica-based mineral is an average particle size measured before mixing with a PVOH-based resin or applying a treatment such as swelling (the maximum particle size at the center of the weight distribution as measured by the sedimentation method). Is less than or equal to 15 μm and measured by X-ray powder method to obtain C
The thickness of the layer in the axial direction is preferably 9 to 20 °, the one having an average particle size of 10 μm or less is particularly preferable, and the one having an average particle size of 3 μm or less is most preferable.

In the step of producing the swellable fluoromica-based mineral used in the present invention, a small amount of alumina (Al ₂ O ₃ ) may be added to adjust the swellability of the resulting swellable fluoromica-based mineral. is there.

The PVOH resin in the present invention is a polymer obtained by saponifying a polymer containing at least 40 mol% of a vinyl ester represented by a vinyl acetate monomer as a component of the main chain. In this case, a vinyl ester other than vinyl acetate, for example, a vinyl ester such as vinyl propionate or vinyl pivalate may be used instead of vinyl acetate.

Further, the degree of saponification of the PVOH-based resin in the present invention is determined by the molar ratio of the saponified ester group to the ester group existing before the saponification, since the obtained resin composition can exhibit a higher barrier property. In terms of ratio, it is preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, and most preferably 98% or more.

Examples of the comonomer component used in an amount of 60 mol% or less other than the vinyl ester include, for example, various compounds having a double bond in the molecule, such as ethylene, propylene, butylene, and unsaturated carboxylic acid. Among them, ethylene is particularly preferably used because it improves the moisture resistance and moldability of the obtained resin composition and gives a resin composition having excellent characteristics.

That is, a PVOH-based resin obtained by copolymerizing ethylene in the range of 2 to 60 mol% is particularly preferable since it exhibits stable barrier properties over a wide range of humidity and has good barrier properties.
A PVOH resin copolymerized in the range of 50 mol% is more preferable, and PVO copolymerized in the range of 4.5 to 15 mol% is preferred.
H-based resins are most preferred.

Further, in the present invention, other polymers such as polyamide, polyester, polyethylene, polypropylene, copolymer of ethylene and propylene, styrene, isoprene, P
MMA, polyethylene glycol, and the like can be used by being blended with the PVOH.

The degree of polymerization of the PVOH-based resin in the present invention is not particularly limited. However, when a stretching operation described below is applied, or when a high external force is applied to the resin composition layer, etc. From the viewpoint of mechanical properties, stretchability, and the like, the degree of polymerization after saponification is preferably in the range of 300 to 2400, more preferably in the range of 500 to 2000, and in the range of 700 to 1500. Most preferred.

Further, in the present invention, it is preferable to add a crosslinking agent to the PVOH-based resin, since good results such as improvement of water resistance and mechanical properties of the resin composition can be obtained. As such a crosslinking agent, any known one is preferably used. Examples of the crosslinking agent include boron compounds such as boric acid, zirconium salts, titanium compounds such as titanium tetralactate, compounds having a plurality of epoxy groups and / or isocyanate groups, and the like.
Such a cross-linking agent is impregnated with a vinyl acetate polymer-based resin before saponification, a saponification step, a solution preparation step, or a swellable synthetic mica or a dispersion thereof, a coating liquid, or a composition formed into a film. Can be added at any process step.

The amount of the swellable fluoromica mineral is PVO.
It is 0.01 to 200 parts by weight based on 100 parts by weight of the H-based resin. If the amount is less than 0.01 part by weight, the effect of improving the barrier property aimed at by the present invention is not sufficient, and if it exceeds 200 parts by weight, the decrease in toughness is large, the viscosity becomes large and the film formation becomes difficult, However, it is not preferable because adverse effects such as easy generation of ash appear.

Various methods can be used for producing the resin composition of the present invention. For example, after the polymerization of vinyl acetate polymer, swellable fluoromica-based minerals are added,
Saponification, concentration, a method of obtaining a composition by drying, or
The raw materials are fed to the extruder in a lump, and the
A method of dispersing swellable fluoromica in a VOH-based resin,
Further, there is a method in which a solvent, a PVOH-based resin, and swellable fluoromica are charged all at once and kneaded using a homogenizer or the like.

Of these, PVOH is used in advance.
Solvent-based resin in water ま た は or water and organic solvent (lower alcohol such as methyl alcohol, isopropyl alcohol)
A solution dissolved in a mixed solvent｝ and a swellable fluoromica dispersion liquid are independently prepared, then mixed and stirred, concentrated and dried by evaporation, etc. to obtain a composition depending on the PVOH resin composition. Any solvent can be selected, the dispersion of swellable fluoromica is performed reliably and completely, its performance can be maximized, the solution stability of a single solution is remarkably excellent, and it is easily mixed with each other Therefore, it has various advantages such as excellent preparation and storage of raw materials and excellent productivity when used as a coating material, and is a practically most preferable method for producing a composition.

The resin composition of the present invention can be used as a molded article having a barrier property by injection molding or the like, but is most preferably used as a film. In that case, it is of course possible to use it as a single-layer film, but it is possible to add functions such as heat welding, protect against mechanical action from the outside, laminate with other materials to improve handling, or improve design. Therefore, it is particularly preferable to provide a printing layer. As a method for forming such a film,
Any of the usual forming methods can be used. In this case, the optimal molding method is slightly different depending on the composition of the PVOH-based resin. The film can be formed into a single film or a multilayer film having at least one layer made of the composition of the present invention on another substrate by a method such as a dipping method, a calendar coating method, and a spray coating method.

Further, the monolayer or multilayer film of the present invention can also obtain a high degree of performance by adding a stretching operation. Such a stretching operation includes, for example, uniaxial stretching, sequential or simultaneous biaxial stretching, and the like. As for the stretching ratio in such a stretching operation, it is recommended that the area after stretching with respect to the area before stretching is 2 to 15, more preferably 7 to 11 times.

The thickness of the present resin composition layer in such a film is not particularly limited, but is preferably 0.1 to 100 μm, preferably 0.3 to 50 μm, and more preferably 0.5 to 30 μm in average thickness. Particularly preferred. 0.1μ
If it is less than m, the barrier properties may be insufficient even with the present resin composition, and if it exceeds 100 μm, the elastic modulus becomes too high, and the film becomes poor in handleability. The required thickness of other materials to be laminated on the film is to be determined according to the purpose, and is not particularly specified.

When the thus obtained resin composition of the present invention is used, a film having excellent barrier properties against various gases represented by oxygen gas, solvents, and the like can be obtained.
By using such a film, for example, when it is used as a packaging material for food, it prevents deterioration and significantly improves the expiration date, and when used as a container for medicines, etc., it prevents leakage of the contents and prevents deterioration due to oxygen and the like. When used as a protective gear material, it can prevent permeation and contact of harmful substances, and can improve safety and hygiene.

[0030]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In addition,% in the text indicates% by weight unless otherwise specified, and each property was measured by the following method. The resins and fillers used in the text were dried at 80 ° C. for 12 hours or more unless otherwise specified.

Oxygen permeability MODERN CONTROLS INC. The measurement was carried out according to a method described in JIS K7126 (isobaric method) under the conditions of 20 ° C., 85% RH and 20 ° C., 100% RH using an oxygen transmission amount measuring apparatus MOCONOX-TRAN 2/20. The oxygen permeability referred to in the present invention is defined as the oxygen permeability (ml / m ² · day · atm) measured at an arbitrary film thickness of a film composed of a single layer, and a film thickness of 2 μm.
value converted to the amount of oxygen permeation in m (ml · 2 μm / m ² ·
day.atm).

When measured on a film consisting of a single layer,
The moisture permeability (g / m 2) was measured under the conditions of 40 ° C. and 90% RH according to the description of JIS Z0208 and measured at an arbitrary film thickness.
² · day), a value (g · 30 μm / m ² · day) converted to a moisture permeability at a film thickness of 30 μm was calculated.

Internal Haze A part of the sample film was cut out, silicone oil was applied, and AST was used with HR-100 manufactured by Murakami Color Research Laboratory.
The haze value was measured according to MD1003-61.

Example 1 1) Preparation of Resin Solution A saponification degree of 99.9% A saponified ethylene-vinyl acetate copolymer having an ethylene content of 8% (Kuraray Co., Ltd., Kuraray Povar RS105C (TM)) was dissolved in warm water and 10% Was prepared. This is called resin solution A.

2) Preparation of Swellable Fluorine Mica Dispersion Swellable Fluorine Mica (Somasif M manufactured by Corp Chemical Co., Ltd.)
E-100 (TM)) was dispersed in water so as to have a concentration of 2%, and was subjected to an ultrasonic cleaner for 2 hours to prepare a dispersion. This is called filler liquid B.

3) Preparation of Coat Film A resin solution A and a filler dispersion B were mixed so that the ratio of fluoromica in the total solid content was 5% to prepare a coat solution. After forming a coat layer on the OPET film using a bar coater, the film was peeled off to obtain a film having a thickness of 20 μm. The moisture permeability, oxygen permeability and internal haze of this film were measured. Table 1 shows the results.

Further, the coated film obtained in 3) was
The film was uniaxially stretched in the machine direction at 10 ° C. to obtain a film stretched four times. The moisture permeability, oxygen permeability and internal haze of this film were also measured. Table 1 shows the results.

Further, the coated film obtained in 3) was
Heat treatment was performed at 80 ° C. for 3 minutes. For this, the moisture permeability and oxygen permeability were measured. Table 1 shows the results.

Example 2 A film was prepared in exactly the same manner as in Example 1 except that the mixture was such that the ratio of fluorine mica in the total solid content was 30%, and various properties similar to those of the example were measured. Table 1 shows the results.

Comparative Example 1 The same test as in Example 1 was conducted except that the resin solution A alone was used as the coating solution. Table 1 shows the results.

Comparative Example 2 Montmorillonite (Pure CWC cl manufactured by Nanocor) was used instead of swellable fluoromica as a filler.
ay (TM)), except that the same test as in Example 2 was performed. Table 1 shows the results.

Comparative Example 3 The same test as in Example 2 was carried out except that talc (LMR (TM) manufactured by Fuji Talc) was used instead of swellable fluoromica as a filler. Table 1 shows the results.

Example 3 Water / n-propanol mixed solvent (n-propanol 6
5%) and a saponified ethylene-vinyl acetate copolymer having an ethylene content of 32 mol% (EVAL EP-F10 manufactured by Kuraray Co., Ltd.)
1 (TM)) was dissolved to a concentration of 10%. This is called resin solution C.

Swellable fluorine mica (Corp Chemical Co., Ltd.)
Somasif ME-100 (TM)) was dispersed in water so as to have a concentration of 4%, and was subjected to an ultrasonic cleaner for 2 hours to prepare a dispersion. This is called filler liquid D.

Example 1 was the same as Example 1 except that a mixture of the resin liquid C and the filler liquid D was used so as to have a filler concentration of 5% based on the total solid content, and that the heat treatment temperature was 140 ° C. Exactly the same test was performed. Table 1 shows the results
Shown in

Example 4 The same test as in Example 3 was carried out except that the filler concentration relative to the total solid content was 20%. Table 1 shows the results.

Comparative Example 4 The same test as in Example 3 was conducted except that the resin solution C alone was used as the coating solution. Table 1 shows the results.

Example 5 Saponified vinyl acetate polymer (Kuraray Co., Ltd., Kuraray Poval 105MC (TM)) was dissolved in water to a concentration of 20%. This is called a resin liquid E.

The same test as in Example 1 was conducted except that a mixture of the resin liquid E and the filler liquid D was used so as to have a filler concentration of 2% based on the total solid content. Table 1 shows the results.

Example 6 The same test as in Example 5 was conducted except that the filler concentration relative to the total solid content was 60%. Table 1 shows the results.

Comparative Example 5 The same test as in Example 5 was conducted except that the resin solution E alone was used as the coating solution. Table 1 shows the results.

Example 7 Saponified ethylene-vinyl acetate copolymer resin having an ethylene content of 44 mol% (Eval EP-E105 manufactured by Kuraray Co., Ltd.)
After dry blending 10 parts by weight of swellable fluorine mica (Somasif ME-100 (TM) manufactured by Corp Chemical Co.) with 90 parts by weight, the mixture is kneaded and pelletized at 220 ° C. using a twin screw extruder to obtain a resin composition. Was. Further, using a single screw extruder, the extruder temperature was 220 ° C. and the roll temperature was 50 ° C.
And a film having a thickness of 15 μm was obtained. The same evaluation as in Example 3 was performed using this film. Table 1 shows the results.

Comparative Example 6 The same test as in Example 7 was carried out except that no swellable fluorine mica was added. Table 1 shows the results.

Example 8 Ethylene-vinyl acetate having a polymerization degree of 1200 and an ethylene content of 8 mol% was dissolved in methanol to a concentration of 30%, and swellable fluoromica (Somasif ME-100 manufactured by Corp Chemical Co., Ltd.) was dissolved therein. (TM)) was added to 10% of the total solid content. Further, 0.10 molar equivalent of sodium hydroxide was added as a methanol solution per vinyl acetate unit, and saponification was performed according to a conventional method to obtain a swellable fluorine-mica-containing ethylene-vinyl acetate polymer saponified gel. The saponification degree of the obtained saponified ethylene-vinyl acetate polymer is 99 mol% (JIS 672).
According to 6. )Met. After drying, the resin composition was dissolved in warm water to obtain a 10% aqueous solution. Except that this was used as a coating solution, the same test as in Example 1 was performed. Table 1 shows the results.

Comparative Example 7 The same test as in Example 8 was carried out except that no swellable fluorine mica was added. Table 1 shows the results.

Example 9 Swellable fluorinated mica (Somasif M manufactured by Corp Chemical Co., Ltd.)
E-100 (TM)) was dispersed in water to a concentration of 4%, and allowed to stand for 7 days. This is called filler liquid F.

The same test as in Example 2 was conducted except that a mixture of the resin liquid A and the filler liquid D was used so as to have a filler concentration of 30% with respect to the total solid content. Table 1 shows the results.

Example 10 Saponification degree 99.9% Saponified ethylene-vinyl acetate copolymer having an ethylene content of 8% (Kuraray Kuraray Povar RS105C (TM)) and swellable fluoromica (Somasif ME-100 manufactured by Corp Chemical Co., Ltd.) (TM)) was previously mixed so that the fluorine mica content was 20%, and then the mixture was dissolved in warm water and subjected to ultrasonication for 2 hours. A test was performed in the same manner as in Example 1 except that this was used as a coating solution. Table 1 shows the results.

Example 11 Dymonite manufactured by Topy Industries as swellable fluorine mica
The test was performed in exactly the same manner as in Example 2 except that DP-DM (TM) was used. Table 1 shows the results.

[0060]

[Table 1]

Example 12 The film prepared in Example 5 was treated with 180
After heat treatment at 4 ° C, the oxygen permeability after 4 times uniaxial stretching was adjusted to 65% humidity.
It was measured under the condition of RH. The oxygen permeability was 1.
The values were 0, 0.6, and 0.4 CC · 2 μm / m ² · day · atom.

COMPARATIVE EXAMPLE 8 The film prepared in Comparative Example 5 was treated with 180
After heat treatment at 4 ° C, the oxygen permeability after 4 times uniaxial stretching was adjusted to 65% humidity.
It was measured under the condition of RH. The oxygen permeability is 2.
The values were 0, 1.5, and 1.0 CC · 2 μm / m ² · day · atom.

Compare Examples 1 and 2 with Comparative Example 1, Examples 3 and 4 with Comparative Example 4, Examples 5 and 6 with Comparative Example 5, Example 7 with Comparative Example 6, and Example 8 with Comparative Example 7. For example, it can be seen that the present invention has a small oxygen permeability and a remarkably improved oxygen barrier property, and a small water vapor permeability and an improved water vapor barrier property. Furthermore, when Example 2 is compared with Comparative Examples 2 and 3, swellable fluoromica / PVOH
It can be seen that the above-described barrier properties are remarkably superior to the combination of the conventional resins with other conventionally known inorganic filler compounded products. Regarding transparency,
It can be seen that the films obtained in the examples of the present invention are not particularly inferior.

[0064]

According to the present invention, it is possible to obtain a resin composition which is excellent in barrier properties of various substances represented by oxygen gas, water vapor and the like, especially in a high humidity environment, and has stable performance. Further, by using the present resin composition for a part of a container or the like, it is possible to prevent deterioration of the contents and the like for a much longer time than conventional products.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4F071 AA28 AA29 AA78 AB26 AB30 AF08 AH04 BA03 BB02 BB08 BC01 4F100 AC05A AC05H AC05K AK69A AT00B BA01 BA02 BA10A BA10B GB15 JD02 YY00A 4J002 BE021 BE031 DJ0140 DJ076

Claims (6)

[Claims] 1. Saponified vinyl acetate polymer resin 100
Swellable fluoromica-based mineral 0.01 to 20 parts by weight
A resin composition having 0 parts by weight. 2. The resin composition according to claim 1, wherein the swellable fluoromica-based mineral is obtained by heating a mixture of talc and a silicide or fluoride of sodium and / or lithium. 3. The swellable fluoromica-based mineral is talc 90.
The resin composition according to claim 1, which is obtained by heating a mixture of about 65% by weight and 10 to 35% by weight of sodium and / or lithium silicofluoride or fluoride. 4. A solution of a saponified vinyl acetate polymer resin and a dispersion obtained by dispersing a swellable fluoromica compound,
The method for producing a resin composition according to claim 1, wherein the resin composition is dried. 5. A film comprising the resin composition according to claim 1. 6. A multilayer film having at least one layer comprising the resin composition according to claim 1.