JPH04164943A - Saponified ethylene-vinyl acetate copolymer composition having improved property and use thereof - Google Patents

Abstract

PURPOSE:To improve oxygen barrier properties, moldability, and flexibility by compounding a saponified ethylene-vinyl acetate copolymer, an ethylene copolymer, and a specific graft polymer. CONSTITUTION:100 pts.wt. polyolefin resin having a degree of polymn. of 350-45000 and a melt flow rate (230 deg.C, 2160g load) of 0. 1-5g/10min is allowed to undergo the graft reaction with 0.05-10 pts.wt. ethylenically unsatd. carboxylic acid (deriv.)(e.g. maleic acid) and then reacted with 0.01-1mol (per mol of carboxyl group) of a polyamide having a degree of polymn. of 80-1000 to give a graft polymer. Then, 50-99.5wt.% saponified ethylene-vinyl acetate copolymer having an ethylene content of 20-60mol%, a degree of saponification of 95mol% or higher, and a melt flow rate of 0.5-100g/10min, 0.4-50wt.% ethylene copolymer (e.g. an ethylene-vinyl acetate copolymer) having a density of 0.90-0.94g/cm<3> and a melt flow rate of 0.3-30g/10min, and 0.1-15wt.% the graft polymer are compounded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides ethylene-acetic acid which has excellent oxygen barrier properties and has significantly improved formability such as stretchability and film-forming properties, and physical properties such as flexibility. The present invention provides a saponified vinyl copolymer composition.

[Prior art] Saponified ethylene-vinyl acetate copolymer has oxygen barrier properties,
Due to its excellent properties such as mechanical strength, it is widely used in various applications such as films, containers, fibers, etc.

However, when the saponified copolymer is processed into a film or sheet, it causes variations in film thickness, reducing the commercial value, and the molded product lacks stretchability and flexibility, so deep drawing is required. The current situation is whether stretching unevenness occurs during processing that involves stretching, or whether pinholes or the like occur during use of the molded product, which limits its use as a packaging material.

As a countermeasure against this, for example, laminating a water-resistant resin such as polyolefin to a saponified ethylene-vinyl acetate copolymer film or sheet, or blending polyolefin with the saponified product to improve stretchability and flexibility. is being attempted.

[Problems to be Solved by the Invention] However, the former method requires a lamination operation, and the latter method does not necessarily have sufficient compatibility between the saponified ethylene-vinyl acetate copolymer and the polyolefin. Efforts have been made to eliminate this drawback by using various additives in combination, but this does not provide a fundamental solution, and while the saponified ethylene-vinyl acetate copolymer retains its original characteristics, However, it is still insufficient to improve film thickness accuracy, stretchability, and flexibility, and a solution is desired.

[Means for Solving the Problem] As a result of intensive research to solve the problem, the present inventors found that (A) saponified ethylene-vinyl acetate copolymer, 50
~99.5% by weight, (B) ethylene copolymer with a density of 0.90 to 0.949/cm3 is 0.4
~50% by weight, (C) a graft polymer obtained by grafting a polyolefin resin with an ethylenically unsaturated carboxylic acid or a derivative thereof, and further reacting with a polyamide;
The present invention was completed by discovering that a saponified ethylene-vinyl acetate copolymer composition containing 1 to 15% by weight of O can achieve the object.

Hereinafter, the present invention will be described in detail, focusing on the use of such a composition, especially a molded product.

The saponified ethylene-vinyl acetate copolymer (A) targeted by the present invention has an ethylene content of 20 to 60 mol%, preferably 25 to 55 mol%, and a degree of saponification of the vinyl acetate component of 95 mol% or more. .

If the ethylene content is less than 20 mol %, the oxygen barrier properties at high humidity will decrease, while if it is 60 mol % or more, physical properties such as oxygen barrier properties and printability will decrease. Furthermore, if the degree of saponification is less than 95 mol%, oxygen barrier properties and moisture resistance will decrease. Among such saponified materials, those having a melt fluorate (210° C., 21609, the same applies hereinafter) of about 0.5 to 1001 J/IO min are useful.

In addition, the saponified copolymer further contains a small amount of propylene, isobutyne, α-olefin such as α-octene, α-dodecene, α-octadecene, unsaturated carboxylic acid or a salt thereof,
Comonomers such as partial alkyl esters, complete alkyl esters, nitriles, amides, anhydrides, and unsaturated sulfonic acids or salts thereof may be contained as co-sealing components.

The ethylene copolymer (B) includes low-density polyethylene and linear low-density polyethylene, which are easily available commercially, as well as ethylene-vinyl acetate copolymers, ethylene-acrylic ester copolymers, and the like.

Both have a density of 0.9 (1-0.94fl/c
m"cJ IS K 6760). It is difficult to obtain the effects of the present invention with medium-density polyethylene or high-density polyethylene other than such polyethylene.

Among (B), melt fluorate (190℃, load 21
60g (the same applies hereafter) is often used for about 0.3 to 309/70 minutes.

In the present invention, blending of (C) is essential to ensure good compatibility between (A) and (B).

(C) is a craft polymer obtained by subjecting a polyolefin resin to a graft reaction with an ethylenically unsaturated carbonic acid or its derivative, and further reacting the carboxylic acid or its derivative with a polyamide.

The graft polymer is prepared by dissolving or suspending the polyolefin resin in a suitable solvent, or activating the polyolefin resin chain in the molten state with a peroxide or diazo initiator, and then adding an ethylenically unsaturated carboxylic acid to the polyolefin resin chain. Alternatively, it is produced by grafting a derivative thereof to obtain a polymer, and then mixing the polymer and polyamide in a molten state.

Brabenders, path blenders, single screw extruders, Wehner and Frypler types 2 are used for such reactions.
A screw extruder or the like is used.

The degree of polymerization of the polyolefin resin used is 350 to 45.
000. Preferably, a number of about 500 to 10,000 is selected. Melt fluorate (230'C1 load 216
Of, the same applies hereinafter) and LCIiO, 1 to 50f//about 10 minutes, which is practical.

The reaction ratio of polyolefin resin and ethylenically unsaturated carboxylic acid or its derivative is 10010.05 by weight
~I 00/I O1 preferably +0010.5~10
It is 0/3.

If it is less than 10010.5, the effect of improving compatibility is insufficient, and if it is more than l 00/I 0, the viscosity increases during molding and is impractical.

The degree of polymerization of the polyamide is practically 80 to 1000, preferably about 100 to 500, and the reaction ratio is preferably 0.01 to 1 mol, preferably 0.05 to 0.09 mol per carboxyl group.

Examples of the polyolefin resins mentioned above include linear low-density, low-density, and high-density polyethylenes, ionomers, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester copolymers, and the like. Especially linear low density polyethylene, low density polyethylene, ethylene-propylene copolymer, ethylene-
Vinyl acetate copolymers are of practical importance.

The ethylenically unsaturated carboxylic acids or derivatives thereof to be grafted onto the backbone polymer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, or their anhydrides and half esters. means.

Polyamides can also be produced by well-known methods such as polyaddition of lactams, polycondensation of aminocarboxylic acids, and polycondensation of diamines and dicarboxylic acids.

Specifically, the above-mentioned polyamide raw materials include lactams such as ε-caprolactam, enantholactam, capryllactam, lauryllactam, α-pyrrolidone, and α-piperidone, 6-aminocaproic acid, 7-aminohebutanoic acid, and 9-aminononane. acids, ω-amino acids such as 11-aminoundecanoic acid, adipic acid, glutaric acid, pimelic acid, superic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadionic acid, hexadecadionic acid, hexadecenedioic acid, eico Sandionic acid, eicosadienedionic acid, diglycolic acid, 2,2.4-trimethyladipic acid, xylylene dicarboxylic acid, 1.4-
Dibasic acids such as cyclohexane dicarboxylic acid, terephthalic acid, isophthalic acid, hexamethylene diamine, tetramethylene diamine, nonamethylene diamine, undecamethylene diamine, F decamethylene diamine, 2,2
Diamines such as ゜4 (or 2,4.4)-)limethylhexamethylene diamine, bis=(4,4゜-aminone chlorohexyl) methane, and metaquinolyl diamine can be mentioned. Furthermore, monoamines such as laurylamine and oleylamine may be used as appropriate for the purpose of controlling the molecular weight.

In the composition of the present invention, the blending ratio of (A), (B), and (C) is 50 to 99.5% by weight, preferably 60% by weight.
~95% by weight, (B) 0.4-50% by weight, preferably 4.5-35%, (C) 0.1-15% by weight, preferably 5-10% by weight. .

If (A) is 50% by weight or less or (B) is 50% by weight or more, oxygen barrier properties will be low, while if (A) is 99.5% by weight or more or (B) is 0.4% by weight or less, stretchability will decrease. , lacks flexibility, and tends to cause uneven film thickness. or,(
If C) is less than 0.1% by weight, the compatibility between (A) and (B) will be poor, making it difficult to obtain the effects of the present invention, and if it is more than 15% by weight, long-run stability will be poor, which is disadvantageous.

Thus, such compositions have a wide range of uses such as molded products, adhesives, coatings, etc., and the composition of the present invention is widely used in molded products, such as pellets, films, notebooks, containers, etc. by melt-kneading. It is molded into fibers, rods, tubes, and various molded products. These pulverized products (when reusing recovered materials, etc.) and pellets are often used for melt molding again.

As the melt molding method, extrusion molding (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and injection molding are mainly employed. The melt molding temperature is often selected from a range of 170 to 270°C. In addition to the above-mentioned injection molding methods, methods such as two-color molding and injection blow molding can be used to obtain molded products with good dimensional accuracy.

During such molding, it is of course possible to use two or more saponified ethylene-vinyl acetate copolymers having various ethylene contents and degrees of saponification. In addition, in melt molding, plasticizers (polyhydric alcohols, etc.), stabilizers, surfactants, crosslinking substances (epoxy compounds, polyvalent metal salts, inorganic or organic polybasic acids or their salts, etc.), fillers, Appropriate amounts of colorants, reinforcing fibers (glass fibers, carbon fibers, etc.), hydrotalcite, etc. can be blended. In addition, various other thermoplastic resins can be blended in appropriate amounts, and examples of such other thermoplastic resins include polyolefins other than (B), modified polyolefins obtained by graft-modifying these with unsaturated carbonic acids or derivatives thereof, and polyamides. , polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyurethane, polyacetal, polycarbonate, melt-moldable polyvinyl alcohol resin, and the like.

The composition of the present invention is often put to practical use in the form of a laminated structure having at least one layer of the composition, in addition to producing a molded product having only a single layer of the composition as described above.

In manufacturing the laminated structure of the present invention, other base materials are laminated on one or both sides of the layer of the composition of the present invention. Examples of the lamination method include melting a thermoplastic resin onto a film or sheet of the composition. A method of extrusion, a method of melt-extruding the composition of the present invention onto a base material such as a thermoplastic resin, a method of co-extruding the composition of the present invention with another thermoplastic resin, and a method of co-extruding the composition of the present invention onto a base material such as a thermoplastic resin. Examples include a method of laminating a film or sheet of another base material with a film or sheet of another base material using a known adhesive such as an organic titanium compound, an isocyanate compound, or a polyester compound.

In the case of coextrusion, partner resins include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-acrylic acid. Single or copolymers of olefins such as ester copolymers, polypropylene, propylene-α-olefins (α-olefins having 4 to 20 carbon atoms) copolymers, polybutene, polypentene, or single or copolymers of these olefins Broadly defined polyolefin resins such as those obtained by graft-modifying the polymer with unsaturated carboxylic acid or its ester, polyesters, polyamides, copolymerized polyamides,
Examples include polyvinyl chloride, polyvinylidene chloride, acrylic resin, styrene resin, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, and chlorinated polypropylene.

A saponified ethylene-vinyl acetate copolymer can also be coextruded.

Furthermore, when a molded product such as a film or sheet is obtained from the composition of the present invention and extrusion coated with another base material or laminated with a film or sheet of another base material using an adhesive, In addition to the above-mentioned thermoplastic resin, any base material (paper, metal foil, -axially or biaxially stretched plastic film or sheet, woven fabric, nonwoven fabric, metal wire, wood surface, etc.) can be used.

The layer structure of the laminated structure is such that the layer of the composition of the present invention is A (AI
+Ah, , ), and other base materials, for example, thermoplastic resin layers, are B (B+, By, , ), and if it is in the form of a film, sheet, or bottle, it will not only have a two-layer structure of A/H. , B/A/B%A/B/A, A+/At/B, A/B+
/Bt, B/A/B, By/B, /A/B, /B! Any combination is possible, such as A, B in filament form.
Any combination is possible, such as a bimetal type, a core (A)-sheath (B) type, a core (B)-sheath (A) type, or an eccentric core-sheath type.

In addition, in the case of coextrusion, blending A with B, B with A,
At least one of A and B may be blended with a resin that improves the adhesion between both layers.

The shape of the laminated structure may be arbitrary, and examples thereof include films, sheets, tapes, bottles, pipes, filaments, and irregular cross-section extrudates.

In addition, the obtained laminated structure may be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, tri-laminate treatment, solution or melt coating treatment, bag making treatment, search processing, box processing, tube processing, split processing, etc. as required. Is it possible to do this?

Further, the molded product or laminated structure of the present invention can be stretched as necessary to improve its physical properties.

In the present invention, a film serving as an original fabric is manufactured by melt-molding the composition. There is no particular limit to the thickness of the film.
It can be set to several μ to several 100 μ. Incidentally, the film referred to in the present invention means a film in a broad sense including forms such as sheets, tapes, tubes, and containers.

Since such a film has a uniform thickness, it has extremely high product value, and the stability of the film thickness is maintained even if the molding process is continued for a long period of time.

The film obtained as described above is subjected to humidity control treatment such as moisture absorption or drying, if necessary, and then subjected to stretching.

The stretching may be either -axial stretching or two-wheel stretching,
The effects of the present invention can be maximized by stretching at as high a magnification as possible. - In the case of axial stretching, it is preferred that the stretching be 1.5 times or more, particularly 2 times or more. In the case of biaxial stretching, the area magnification is preferably 15 times or more, particularly 2 times or more, and even 4 times or more.

The present invention is characterized in that high stretching of 5 times or more, especially 7 times or more is possible.

As the stretching method, in addition to a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blowing method, etc., methods with a high stretching ratio among deep drawing forming, vacuum forming, etc. can be adopted. In the case of two-wheel stretching, either a simultaneous biaxial stretching method or a sequential biaxial stretching method can be employed.

The stretching temperature is selected from a range of about 40 to 150°C.

After the stretching is thus completed, heat setting is then performed. Heat setting can be carried out by a well-known method, and the stretched film is kept under tension at 50 to 160°C, preferably 8°C.
Heat treatment is performed at 0 to 160°C for about 2 to 600 seconds.

In addition, the obtained stretched film may be subjected to cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making treatment, search processing, box processing, tube processing, split processing, etc., as necessary. I can do it.

Films, sheets, containers, etc. obtained from the composition of the present invention are useful as packaging materials for various foods, pharmaceuticals, industrial chemicals, agricultural chemicals, etc.

Effect 1 In the present invention, a specific (C) graft polymer is blended into a composition of (A) a saponified ethylene-vinyl acetate copolymer and (B) an ethylene copolymer having a specific density. The compatibility between (A) and (B) is significantly improved by
The molded product obtained from the composition has excellent oxygen barrier properties and (
The drawbacks of A) such as stretchability, film thickness unevenness, and flexibility are significantly improved.

[Example] Next, Examples will be given to further explain the composition of the present invention. Sample Preparation Examples 1 to 8, Control Examples 1 to 6 The composition pellets consisting of the combination of C) are mixed using a Hennel mixer, and the mixture is fed to an extruder equipped with a T-die and melt-kneaded.
A film with a thickness of 30 μm was produced by extrusion through a die. (
However, a 180μ film was used for the stretchability test) The extrusion molding conditions were as follows.

Extruder: 40a+m diameter extruder screw: tip dalmage type, L/D=28, C
R=3.0 Extrusion temperature=230°C Screw rotation speed: 40 rpm The results for the obtained film are shown in Table 1.

Examples 9-13 Outside! (1); Nylon 6 [MFR: 49/10 minutes, (230°C, 2160 g)] Intermediate layer (■); (A), (B), (C) composition adhesive layer (■) of the present application, anhydrous maleic Acid-modified ethylene-vinyl acetate copolymer CMFR; 2.5y/10min (190'C1216i
)) Inner layer (■), ethylene-vinyl acetate copolymer with vinyl acetate content 1O% CMFR: 2y/I 0 min (190'C1C1216
O] Using each of the above resins, the layer structure and film thickness (μ) are (1
)/(II)/(I[I)/(IV)=20/10
A 15/20 four-layer laminate structure was manufactured under the following conditions. (However, 80/40/20/80 was used for the stretching test) Molding conditions Extruder 40 nm diameter extruder (for inner layer) 40 mm diameter extruder (for middle layer) 3 om diameter extruder (for adhesive layer) 40 mm diameter extruder Machine (for outer layer) Both screws L/D=28 Compression ratio 3.2
Screw 1 rotation speed For inner layer 40 rpm For intermediate layer 2 Orpm For adhesive layer 2 Orpm For outer layer 4 Orpm T die with die 4 layer compiling adapter Die width 45
0mm Extrusion temperature inside/outside/adhesion extruder C, = 190°C Ct = 200°C c3 = 210°C
C,=220℃ Intermediate layer extruder Cr=180℃ Ct-200℃c3=220
℃ C, = 220℃ compinning adapter 210℃ T die 2
The 10°C results are shown in Table 2.

Examples 14 to 18 Inner layer (I), outer layer (■); Low density polyethylene (MF
R; 2.0Iil/10 minutes) Adhesive layer (II), (IV); Maleic anhydride linear low density polyethylene (MFR+ 29710 minutes) intermediate layer (m); (A), (B) of the present application, Composition (C) Using each of the above resins, the layer structure and film thickness (μ) are (r)/(I
f)/(I)/(1'V)/(V) -2015/10
A 15/20 5-layer laminate structure was manufactured under the following conditions.

(However, 80/20/40/20/80 was used for the stretchability test.) Extruder 40+am diameter extruder (for inner and outer layers) 40sm diameter extruder (for middle layer) 30im diameter extruder (for adhesive layer) Screw: Both L/D = 2.8 Compression ratio 3.2
Screw 1 rotation speed For inner layer, outer layer 65 rpm For intermediate layer 2 Orpm For adhesive layer 30 rpm T die with die 5 layer compinning adapter Die width 45
0mm Extrusion temperature inside/outside/adhesion extruder C, =] 90℃ Cz-20o℃C, = 21
0°C G, = 220°C Intermediate layer extruder C, = 180°C C2 = 200° CC5 = 22
0°CC, = 220°C Compining adapter 210°C T die
The 210°C results are shown in Table 3.

[Effects] The composition of the present invention comprising (A) a saponified ethylene-vinyl acetate copolymer, (B) an ethylene copolymer with a specific density, and (C) a specific graft copolymer has excellent oxygen barrier properties. sex,
Provides molded products with stretchability, film thickness accuracy, and flexibility.

Claims (1)

[Claims] 1. (A) saponified ethylene-vinyl acetate copolymer,
50 to 99.5% by weight, (B) 0.4 to 50% by weight of an ethylene copolymer with a density of 0.90 to 0.94 g/cm^3, (C) Ethylenically unsaturated carbon in the polyolefin resin A graft polymer obtained by grafting an acid or its derivative and further reacting a polyamide has a molecular weight of 0.1 to 15
A saponified ethylene-vinyl acetate copolymer composition with improved properties comprising a proportion of % by weight. 2. A molded article obtained by melt-molding the composition according to claim 1. 3. A laminated structure comprising at least one layer of the composition according to claim 1. 4. The molded product according to claim 2 or the laminate structure according to claim 3, wherein the molded product or the laminated structure is stretched in at least one axis.