JPH1143572A - Resin composition and its laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in long run property in melt molding and capable of forming a molded product excellent in appearance and interlaminar bonding property by including a saponification product of an ethylene-vinyl acetate copolymer and a specific boric acid salt. SOLUTION: This composition contains (A) a saponification product of an ethylene-vinyl acetate copolymer having 20-60 mol.% ethylene content and >=90 wt.% saponification degree and (B) at least one kind of compound selected from potassium borate, calcium borate and magnesium borate. The content of the component B is preferably 0.001-1 pt.wt. expressed in terms of boron, based on 100 pts.wt. component A. The composition preferably further contains (C) acetic acid in an amount of <=0.05 pt.wt. based on 100 pts.wt. component A. A laminate formed by using a molded product comprising this composition is excellent in interlaminar bonding property after secondary processing such as drawing or deep drawing and useful for packaging films, sheets, etc., for foods, medicines, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH).
The resin composition and the laminate using the same, more specifically, a resin composition having excellent long-run property during melt molding, having less fish eyes and stripes, having excellent appearance, and having excellent interlayer adhesion when formed into a laminate. TECHNICAL FIELD The present invention relates to a product and a laminate using the same.

[0002]

2. Description of the Related Art In general, EVOH is excellent in transparency, gas barrier property, fragrance retention, solvent resistance, oil resistance and the like. It is used after being formed into materials, films and sheets of packaging materials for agricultural chemicals, containers such as bottles, and the like. In such molding, usually, melt molding is performed, and by such molding, it is processed into a shape such as a film shape, a sheet shape, a bottle shape, a cup shape, a tube shape, a pipe shape, and is provided for practical use. (Moldability) is very important, and is generally co-extruded with a base material such as a polyolefin resin via an adhesive layer in order to impart mechanical strength, moisture resistance, heat sealability, and the like. It is a laminate, and the interlayer adhesion of the laminate is also important. That is, the appearance of the molded product (molded product without fish eyes or stripes),
It is necessary to sufficiently satisfy the long run property at the time of melt molding (a molded article free of fish eyes and streaks is obtained even during long time molding), interlayer adhesion, and the like. It has been proposed to incorporate a boron compound into EVOH in order to improve the interlayer adhesion (JP-A-59-192564).
The present applicant has also proposed a molding method of a composition in which boron or a salt thereof is blended with EVOH in order to improve the melt moldability (Japanese Patent Application Laid-Open No. 55-12108).

[0003]

However, the technique disclosed in Japanese Patent Application Laid-Open No. Sho 59-192564 and the method disclosed in Japanese Patent Application Laid-Open No.
In the technology disclosed in -12108, the appearance of the molded product and the long-run property during melt molding are not sufficiently considered, and a new improvement in interlayer adhesion is desired.

[0004]

Accordingly, the present inventor has conducted intensive studies in view of the present situation, and as a result, has found that ethylene-acetic acid having an ethylene content of 20 to 60 mol% and a saponification degree of 90 mol% or more. It has been found that a resin composition comprising a saponified vinyl copolymer (A) and at least one kind (B) selected from potassium borate, calcium borate, and magnesium borate solves this problem, and completed the present invention. I came to. Further, the content of (B) is (A) 1 in terms of boron.
When the amount is 0.001 to 1 part by weight with respect to 00 parts by weight, or when the acetic acid (C) is contained in an amount of 0.05 part by weight or less based on 100 parts by weight of (A), the effect of the present invention is not obtained. Can be obtained remarkably. In measuring the contents of (B) and (C), the contents can be measured by the following method. (B): The resin composition was alkali-melted, and the amount of boron was determined by IPC emission spectroscopy. (C): The resin composition was extracted with hot water, and the extract was neutralized and titrated with alkali to determine the amount of acetic acid. Quantitative

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The EVOH (A) of the present invention has an ethylene content of 2
Those having 0 to 60 mol% (more preferably 25 to 55 mol%) and a saponification degree of 90 mol% or more (furthermore, 95 mol% or more) are used. The gas barrier properties and melt-molding properties of the resin deteriorate, whereas if it exceeds 60 mol%, sufficient gas barrier properties cannot be obtained, and if the saponification degree is less than 90 mol%, the gas barrier properties, heat stability and moisture resistance And the like, and the object of the present invention cannot be achieved. EVOH (A) has a melt index (MI) (210 ° C., load 2160 g) of 0.5 to
The melt index is preferably 100 g / 10 min (more preferably 1 to 50 g / 10 min). If the melt index is smaller than the above range, the inside of the extruder will be in a high torque state at the time of molding and extrusion processing will be difficult. If it is larger than this range, the mechanical strength of the molded product is insufficient, which is not preferable.

The EVOH (A) is obtained by saponification of an ethylene-vinyl acetate copolymer, and the ethylene-vinyl acetate copolymer can be produced by any known polymerization method, for example, suspension polymerization, emulsion polymerization. , A solution polymerization or the like, and saponification of an ethylene-vinyl acetate copolymer can be carried out by a known method. If EVOH is used in a small amount, other comonomers such as α-olefin, unsaturated carboxylic acid compound, unsaturated sulfonic acid compound, (meth) acrylonitrile, (meth) acrylamide, vinyl ether, vinyl silane compound, vinyl chloride and styrene And may be "copolymerized". Also, "post-modified" such as urethanization, acetalization, and cyanoethylation may be used as long as the gist of the present invention is not impaired.

The component (B) used together with the EVOH (A) is at least one selected from potassium borate, calcium borate, and magnesium borate.
The species, more specifically as potassium borate, potassium metaborate, potassium tetraborate, potassium pentaborate,
Potassium hexaborate, potassium octaborate and the like, such as calcium borate, calcium metaborate, calcium tetraborate and the like, and as magnesium borate, magnesium orthoborate, magnesium diborate, Examples thereof include magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, and magnesium hexaborate, and the metaborate, tetraborate, and pentaborate of each metal are preferably used. In addition, (B)
Is preferably 0.001 to 1 part by weight, more preferably 0.1 part by weight, based on 100 parts by weight of boron (A).
001 to 0.5 parts by weight, particularly preferably 0.002 to
When the content of (B) is less than 0.001 part by weight in terms of boron at 0.1 part by weight, the effect of (B) content cannot be obtained, and when it exceeds 1 part by weight, gel or fisheye is not obtained. Frequent occurrence is not preferable.

The method of mixing (containing) (B) with (A) is not particularly limited, and is a method of directly blending (B) with (A) and dissolving (B) in a solvent such as water. After that, a method of mixing with (A), a method of immersing (A) in the solution of (B), and a method of melting (A) in an extruder
A method in which the solution of (B) is added to the water / alcohol solution of (A), followed by precipitation in a coagulation bath and drying of the (porous) precipitate. water/
A method in which the porous precipitate of the alcohol solution is impregnated with the solution of (B) and then dried, for example, is preferred in terms of dispersing (B) more uniformly and efficiently. The method described above for borate salts that are hardly soluble in water is preferably used.

In the present invention, it is preferable that acetic acid (C) is further contained in an amount of 0.05 part by weight or less based on 100 parts by weight of (A).
0.03 parts by weight, particularly preferably 0.0005 to 0.0
If the content of (C) exceeds 1 part by weight and the content of (C) exceeds 0.05 part by weight, the long-run property is undesirably reduced. (A)
The method for containing (C) is not particularly limited,
The same content method as in the above (B) can be adopted,
Further, it can be adjusted during the production of EVOH (A). For example, it is also possible to adjust excess acetic acid (C) used for neutralization of the alkali used in the saponification step by a drying treatment or the like. is there.

The thus obtained resin composition of the present invention may further contain, if necessary, a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, an antibacterial agent, a filler, and other resins. It is also possible to use additives. In particular, a hydrotalcite-based compound, a hindered phenol-based, a hindered amine-based heat stabilizer, and a metal salt of a higher aliphatic carboxylic acid can also be added as a gel generation inhibitor. Further, as the EVOH (A), two or more different EVOHs are used.
It is also possible to use a blend of EVOH whose ethylene content differs by 5 mol% or more and / or whose saponification degree differs by 1 mol% or more, thereby maintaining the gas barrier property. Furthermore, stretchability at the time of high stretch,
This is useful because secondary workability such as vacuum pressure forming and deep drawing is improved.

The resin composition of the present invention thus obtained is
It is often used for molded products, and pellets by melt molding etc.
It is formed into films, sheets, containers, fibers, rods, tubes, various molded products, and the like, and is often subjected to melt molding again using crushed products (such as when reused products) or pellets are used. As the melt molding method, extrusion molding methods (T-die extrusion, inflation extrusion, blow molding, melt spinning,
Injection molding is mainly employed. The melt molding temperature is often selected from the range of 150 to 250 ° C.

The resin composition obtained by the present invention can be used for a molded product as described above, and is particularly used as a laminate comprising a thermoplastic resin layer laminated on at least one surface of a layer made of the resin composition. It is preferably used, and a laminate suitable for practical use is obtained. Since the laminate uses the EVOH composition of the present invention, it has not only excellent gas barrier properties and transparency, but also excellent interlayer adhesion at the time of high stretching and at the time of secondary processing such as vacuum pressure forming or deep drawing. It shows an excellent effect.

In producing the laminate, another substrate is laminated on one or both sides of the layer of the EVOH composition obtained in the present invention. The lamination method is, for example, a film of the composition. A method of melt-extruding a thermoplastic resin into a sheet, a method of melt-extruding the composition on a substrate such as a thermoplastic resin, a method of co-extruding the resin composition with another thermoplastic resin, and A method of laminating a film or sheet of the EVOH composition obtained by the present invention with a film or sheet of another substrate using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, or a polyurethane compound. Is mentioned.

In the case of co-extrusion, the mating resin may be a linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene -Acrylate copolymer, polypropylene, propylene-α-olefin (having 4 to 20 carbon atoms)
Α-olefins) copolymers, polyolefins such as polybutenes and polypentenes, or polyolefins in a broad sense, such as homo- or copolymers of these olefins, or graft-modified homo- or copolymers of these olefins with unsaturated carboxylic acids or esters thereof Resin, polyester, polyamide, copolymerized polyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin,
Examples thereof include polyester elastomer, polyurethane elastomer, chlorinated polyethylene, and chlorinated polypropylene. Saponified ethylene-vinyl acetate copolymer can also be coextruded. Among these, polypropylene, polyamide, polyethylene, ethylene-vinyl acetate copolymer, polystyrene, and PET are preferably used from the viewpoint of ease of coextrusion film formation and practicality of film physical properties (particularly strength).

Further, a molded product such as a film or a sheet is once obtained from the resin composition obtained by the present invention, and another substrate is extrusion-coated thereon, or the film or sheet of another substrate is bonded to an adhesive. In the case of laminating using, any substrate (paper, metal foil, uniaxially or biaxially stretched plastic film or sheet, woven fabric, nonwoven fabric, metal flocculent, woody, etc.) other than the above-mentioned thermoplastic resin can be used. is there. The layer structure of the laminate is such that the layer of the resin composition obtained in the present invention is a (a ₁ , a ₂ ,...)
.), Another substrate, for example, a thermoplastic resin layer b (b ₁ ,
b ₂ ,...), in the case of a film, sheet, or bottle, not only a two-layer structure of a / b but also b / a /
b, a / b / a, a 1 / a 2 / b, a / b 1 / b 2, b 2 /
_{b 1 / a / b 1 /} b 2 , etc. are possible any combination,
In the filament form, a and b are bimetal type, core (a)-
Any combination such as a sheath (b) type, a core (b) -sheath (a) type, or an eccentric core-sheath type is possible.

In the case of co-extrusion, a may be blended with b and b may be blended with a, or at least one of a and b may be blended with a resin for improving the adhesion between the two layers. In the present invention, the laminate is used as it is in various shapes, but it is also preferable to perform a stretching treatment in order to further improve the physical properties of the laminate, breaking, pinholes, cracks,
Since it exhibits an effect of excellent stretchability and interlayer adhesion without delamination or the like, it is a very excellent laminate.

The stretching may be either uniaxial stretching or biaxial stretching, and it is preferable to perform stretching at the highest possible magnification in terms of physical properties. In the present invention, a stretched film or a stretched sheet free from pinholes, cracks, stretch unevenness, delamination and the like during stretching can be obtained.

The stretching method includes a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, and the like.
Of the deep drawing, vacuum forming and the like, those having a high stretching ratio can be employed. In the case of biaxial stretching, any of a simultaneous biaxial stretching method and a sequential biaxial stretching method can be adopted. Stretching temperature is 80
To 170 ° C, preferably about 100 to 160 ° C.

After completion of the stretching, heat setting is performed. The heat setting can be performed by a well-known means, and heat treatment is performed at 80 to 170 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds while keeping the stretched film in a tensioned state. The obtained stretched film should be subjected to cooling, rolling, printing, dry laminating, solution or melt coating, bag making, deep squeezing, box processing, tube processing, split processing, etc. as necessary. Can be.

The shape of the laminate thus obtained may be arbitrary, and examples thereof include a film, a sheet, a tape, a bottle, a pipe, a filament, and an extrudate having a modified cross section. Further, the obtained laminate is heat-treated, cooled, rolled, printed, dry-laminated,
Solution or melt coating processing, bag making processing, deep drawing processing, box processing, tube processing, split processing, and the like can be performed. The films, sheets, containers and the like obtained as described above are useful as various packaging materials for foods, pharmaceuticals, industrial chemicals, agricultural chemicals and the like.

[0021]

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 Ethylene content 35 mol%, saponification degree 99.5 mol%,
E of MI 20g / 10min (210 ° C, load 2160g)
The porous precipitate of the water / methanol solution after saponification of VOH (A) (containing 100 parts of water with respect to 100 parts of EVOH (A)) is washed with a 0.5% acetic acid aqueous solution, and further washed with water. Thereafter, it is poured into an aqueous solution containing 0.2% of potassium tetraborate (B) and 0.1% of acetic acid (C), stirred at 30 ° C. for 5 hours, and dried at 110 ° C. for 8 hours. And EVOH
An EVOH composition of the present invention containing 0.03 parts by weight and 0.009 parts by weight of boron (B1) and acetic acid (C) with respect to 100 parts by weight of (A) was obtained.

Next, the obtained EVOH composition was supplied to a single-screw extruder equipped with a T die, and a thickness of 12 mm was obtained under the following conditions.
A 0 μm EVOH film was molded, and the appearance and long run properties were evaluated in the following manner. (Film forming condition by single screw extruder) Screw inner diameter 40 mm L / D 28 Screw compression ratio 3.2 T die Coat hanger type Die width 450 mm Extrusion temperature C1: 180 ° C, H: 210 ° C C2: 200 ° C, D: 210 C3: 220C, C4: 220C

(Appearance) The film (1)
(0 cm × 10 cm), the appearance of streaks and fish eyes was visually observed and evaluated as follows. Streaks---No streaks were observed.----Streaks were slightly observed, but there was no problem in practical use.----Streaks occurred frequently and could not be used practically. Fisheye ◎---0 to 3 ○ −−− 4 to 10 △ −−− 11 to 50 × −−− 51 or more

(Long run property)
Performed for consecutive days, for the molded film at that time, streak, gel, visually observe the increase in fisheye,
The evaluation was as follows. ○ --- No increase was observed. △ --- A slight increase was observed. × --- A remarkable increase was observed. In addition, using the obtained EVOH composition, a feed block 5-layer T-die was used. Then, a film was formed so as to have a layer structure of polypropylene layer / adhesive resin layer / EVOH composition layer / adhesive resin layer / polypropylene layer to prepare a multilayer laminated film. In addition, the structure of the film is such that the polypropylene layers of both outer layers (the MI of polypropylene is 1.2 g / 10 min) are 100
μm, the adhesive resin layer (the adhesive resin is maleic anhydride-modified polypropylene, and its MI is 2.6 g / 10 min)
The thickness of the EVOH composition layer was 5 μm, and the thickness of the intermediate layer was 50 μm.
With respect to such a multilayer laminated film, stretch unevenness and interlayer adhesion were evaluated as follows.

(Stretching unevenness) The above multilayer structure was 8 cm ×
The sample was sampled at 8 cm, the sample was preheated at 150 ° C. for 1 minute, and successively biaxially stretched at a stretching speed of 100 mm / sec in the order of 3 times in the longitudinal direction and 3 times in the transverse direction (stretching ratio: 9 times). The evaluation was performed according to the following criteria based on the change in appearance of the obtained stretched film. ◎ −−− No streaks were observed at all. ○ −−− Although small streaks were slightly observed, there was no problem in practical use. △ −−− One or two large streaks were generated. Limited to use × −−− Three or more large streaks are generated and cannot be used in practice

(Interlayer Adhesion) The adhesion strength between the EVOH layer and the adhesive layer of the stretched film of the multilayer structure was measured by an autograph at 20 ° C. and a tensile speed of 300 mm / min by the T-peel method. It evaluated as follows. ○ −−− 1000 g / 15 mm or more △ −−− 300 to less than 1000 g / 15 mm × −−− Less than 300 g / 15 mm

Example 2 In Example 1, the porous precipitate after washing with a 0.5% acetic acid aqueous solution was dried at 110 ° C. for 8 hours, and 0.05 parts of magnesium metaborate was added to the porous precipitate in the same direction. An EVOH composition containing 0.01 part by weight and 0.005 part by weight of boron (B1) and acetic acid (C) per 100 parts by weight of EVOH (A) is melt-mixed with a twin screw extruder. Get,
Evaluation was performed similarly.

Example 3 The procedure of Example 2 was repeated except that 0.23 part of calcium metaborate and 0.015 part of acetic acid were added.
An EVOH composition containing 0.04 parts by weight and 0.008 parts by weight of boron (B1) and acetic acid (C) with respect to 100 parts by weight of VOH (A) was obtained and evaluated in the same manner.

Example 4 In Example 2, as EVOH (A), ethylene content was 30 mol%, saponification degree was 99.5 mol%, and MI was 20 g.
EVOH (A) for 10 minutes (210 ° C., load 2160 g)
1) and ethylene content of 42 mol%, saponification degree of 99.6 mol%, MI of 15 g / 10 min (210 ° C., load of 2160
g), except that a mixture of EVOH (A2) (mixing weight ratio of A1 / A2 is 70/30) was used.
An EVOH composition containing 0.02 parts by weight and 0.005 parts by weight of boron (B1) and acetic acid (C) with respect to 100 parts by weight of (A) was obtained and evaluated in the same manner.

Example 5 In Example 1, as EVOH (A), ethylene content was 30 mol%, saponification degree was 99.5 mol%, and MI was 20 g.
EVOH (A) for 10 minutes (210 ° C., load 2160 g)
1) and ethylene content 47 mol%, saponification degree 97 mol%, MI 35 g / 10 min (210 ° C., load 2160 g)
Of EVOH (A2) (A1 / A2 mixture weight ratio of 80
/ 20), except that EVOH (A) was used.
EV containing 0.03 parts by weight and 0.009 parts by weight of boron (B1) and acetic acid (C) with respect to 100 parts by weight
An OH composition was obtained and evaluated similarly.

Comparative Example 1 In Example 1, 0.2% potassium tetraborate (B)
In place of using 0.2% boric acid, and adding boron (B) to 100 parts by weight of EVOH (A).
1) and 0.03 parts by weight of acetic acid (C) and 0.003 part by weight, respectively.
An EVOH composition containing 9 parts by weight was obtained and similarly evaluated. Table 1 shows the evaluation results of the examples and comparative examples.

[0032]

[Table 1]Appearance Long run properties Uneven stretchability Interlayer adhesion  Example 1 ○ ◎ ○ ○ ○ 〃 2 ○ ◎ ○ ○ ○ 〃 3 ○ ◎ ○ ○ ○ 〃 4 ○ ◎ ○ ○ ○５ 5 ○ ◎ ○ ◎ ○ Comparative Example 1 ○ △ × × △

[0033]

The EVOH composition of the present invention contains at least one of potassium borate, calcium borate, and magnesium borate, so that it has excellent long-run properties at the time of melt molding, has less fish eyes, and has an appearance. It is possible to obtain a molded product having excellent properties, and further, as a laminate, having excellent interlayer adhesion of the laminate even after secondary processing such as stretching or deep drawing, and forming various laminates. Food and medicine,
It is very useful for applications such as films, sheets, tubes, bags, containers and the like for packaging of agricultural chemicals and industrial chemicals, and can be suitably used particularly for secondary processed products involving stretching.

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[Procedure amendment]

[Submission date] July 15, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

Example 4 In Example 2, as EVOH (A), ethylene content was 30 mol%, saponification degree was 99.5 mol%, and MI was 20 g.
EVOH (A) for 10 minutes (210 ° C., load 2160 g)
1) and ethylene content of 42 mol%, saponification degree of 99.6 mol%, MI of 15 g / 10 min (210 ° C., load of 2160
g), except that a mixture of EVOH (A2) (mixing weight ratio of A1 / A2 is 70/30) was used.
An EVOH composition containing 0.01 part by weight and 0.005 part by weight of boron (B1) and acetic acid (C) with respect to 100 parts by weight of (A) was obtained and similarly evaluated.

Claims (5)

[Claims] 1. A saponified ethylene-vinyl acetate copolymer (A) having an ethylene content of 20 to 60 mol% and a saponification degree of 90 mol% or more, and potassium borate, calcium borate, or magnesium borate. A resin composition comprising at least one type (B). 2. The content of (B) is (A) 1 in terms of boron.
The resin composition according to claim 1, wherein the amount is 0.001 to 1 part by weight based on 00 parts by weight. 3. The resin composition according to claim 1, further comprising 0.05 part by weight or less of acetic acid (C) based on 100 parts by weight of (A). 4. A laminate comprising a layer made of the resin composition according to claim 1 and a thermoplastic resin layer laminated on at least one surface of the layer. 5. The laminate according to claim 4, wherein the thermoplastic resin is a polyolefin resin.