JPH0598084A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition excellent in impermeability to gas, free from internal delamination, having good environmental stress cracking resistance, and in addition excellent in adhesiveness to polyolefin resin. CONSTITUTION:A resin composition which consists of 5-80wt.% polyolefin resin (A), 10-90wt.% ethylene/vinyl alcohol copolymer resin (B) having an ethylene content of 35-65mol%, and 10-90wt.% polyolefin resin (C) modified with an unsaturated carboxylic acid or its derivative, wherein the melt flow rate (MFR) (determined at 190 deg.C under a load of 2160g) of component A is 1-30g/10min, that of component B is 1-100g/10min, and that of component C is 0.5-30g/10min.

Description

Detailed Description of the Invention

[0001]

The present invention has excellent gas permeation resistance,
The present invention relates to a resin composition having good resistance to environmental stress cracking and excellent adhesiveness to a polyolefin resin.

[0002]

2. Description of the Related Art Polyolefin resins are inexpensive, have excellent mechanical properties, are easy to process, and have good properties such as water vapor permeation resistance and safety and hygiene. It is widely used as a packaging material for toiletries, adhesives, toothpastes, chemicals, etc.

However, since oxygen gas, carbon dioxide gas, and nitrogen gas have high gas permeability, those that affect the quality of the contents due to the invasion of these gases cannot be used or they are extremely short-term. The reality was that it could only be used for a while.

In order to improve the gas permeability of the polyolefin resin, for example, it has been proposed to blend the polyolefin resin with an ethylene-vinyl alcohol copolymer resin having gas permeation resistance (JP-A-49-3898).
4). However, in this method, in order to improve the adhesiveness between the blend and the polyolefin resin, the blending weight ratio of the polyolefin resin must be 50% by weight or more of the total weight, and at this time, the adhesiveness with the polyolefin resin is strong. However, since the compatibility between the polyolefin resin and the ethylene-vinyl alcohol copolymer resin is poor in the blend layer, abnormal flow occurs at the time of molding, resulting in poor appearance. Further, in JP-A-53-39380, polyolefin resin 1
25 to 60 parts by weight of an ethylene-vinyl alcohol copolymer resin having a melt index three times higher than that of a polyolefin resin in 00 parts by weight, and an ethylene content of 70 to
It is proposed to use 5 to 40 parts by weight of the above ethylene-vinyl alcohol copolymer resin having 98% by mol and a saponification degree of 20%. However, this also causes abnormal flow during molding and cannot be put to practical use.

[0005]

The present invention was devised in order to eliminate the above-mentioned drawbacks of the prior art, and improves intralayer peeling which is considered to be caused by poor compatibility, An object of the present invention is to provide a resin composition which has a large in-layer peeling resistance, an excellent gas permeation resistance, a good fluidity and a beautiful appearance.

[0006]

[Means for Solving the Problems] The above objects are as follows: polyolefin resin (A) 5 to 80% by weight, ethylene-vinyl alcohol copolymer resin (B) (hereinafter referred to as EVOH) 1
Polyolefin resin (C) 10-9 modified by 0-90% by weight and unsaturated carboxylic acid or its derivative
0% by weight and (A) melt flow rate (MFR) (JIS K6760, temperature 190
C., value measured under a load of 2160 g) 1 to 30 g / 10
Min, (B) MFR 1-100 g / 10 min and (C)
This is achieved by providing a resin composition having a MFR of 0.5 to 30 g / 10 minutes.

In the present invention, the polyolefin resin (A) means high-density, medium-density or low-density polyethylene, ethylene, vinyl acetate, acrylate ester, or α such as butene, hexene, 4-methyl-1-pentene. An ethylene polymer obtained by copolymerizing olefins,
Ionomer resin, polypropylene homopolymer, polypropylene graft polymerized with ethylene, or propylene with ethylene, butene, hexene, and 4-methyl-1.
-Propylene-based copolymer obtained by copolymerizing α-olefins such as pentene, modified polypropylene blended with rubber-based polymer, poly-1-butene, poly-4-methyl-1-
Penten and the like, of which polyethylene resin is particularly important. The MFR of the polyolefin resin is 1 to 30 g / 10 minutes, preferably 3 to 10 g / 10 minutes.

In the present invention, EVOH (B) is obtained by saponifying an ethylene-vinyl ester copolymer, and vinyl acetate is a typical vinyl ester. However, other fatty acid vinyl esters (vinyl propiolate, vinyl pivalate, etc.) can also be used.

It is important that the ethylene content of EVOH is 35 to 65 mol%, optimally 40 to 60 mol%. The saponification degree of the vinyl ester component is 96%.
Above all, particularly 99% or more of EVOH is suitable as an application target of the present invention because an excellent molded product can be obtained by using it in combination with a polyolefin resin.

The MFR of EVOH (B) is 1 to 100.
g / 10 minutes, preferably 3 g / 10 minutes or more,
Also, preferably 70 g / 10 minutes or less, further 30 g / 1
It is 0 minutes or less.

The EVOH (B) referred to in the present invention may be modified with a copolymerization monomer in the range of 5 mol% or less. Examples of the modifying monomer include propylene, 1-butene, 1-hexene and 4-methyl. -1-Pentene, acrylic acid ester, methacrylic acid ester, maleic acid, fumaric acid, itaconic acid, higher fatty acid vinyl ester, alkyl vinyl ether, N- (2-dimethylaminoethyl) methacrylamide or its quaternary compound, N- Vinylimidazole, or its quaternary compound, N-vinylpyrrolidone, N, N-butoxymethylacrylamide,
Examples thereof include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane and the like.

In the present invention, the polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof means unsaturated such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid and citraconic acid. Carboxylic acid, its ester or its anhydride; methyl acrylate, methyl methacrylate, ethyl acrylate,
At least one selected from the group consisting of propyl acrylate, butyl acrylate, butyl methacrylate, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, sodium acrylate, unsaturated carboxylic acid derivatives such as sodium methacrylate. Polyolefin resin modified by the unsaturated carboxylic acid or its derivative or its blend.
Here, as the polyolefin resin, polyethylene, polypropylene, ethylene-vinyl acetate or ethylene-
Acrylic acid ester copolymers and the like are preferred.

The blending ratio of each component of the resin composition of the present invention is 5 to 80% by weight of the polyolefin resin (A), preferably 10 to 80% by weight, more preferably 10 to 70% by weight.
And 10 to 90% by weight of EVOH (B), preferably 1
0 to 70% by weight, more preferably 10 to 60% by weight, and 10 to 90% by weight, preferably 10 to 80% by weight of a polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof. More preferably, it is 10 to 60% by weight.

Further, the MFR of the resin composition of the present invention is smaller than the value of the logarithmic average MFR obtained by the blending ratio of the resins (A), (B) and (C), so that the environmental stress crack resistance is more excellent. Will be things.

As described above, the resin composition of the present invention is
Since it is composed of a specific compounding ratio of (A), (B) and (C) and a specific MFR, not only gas permeation resistance is excellent, but also physical characteristics such as environmental stress crack resistance are excellent. ..

The blending method for obtaining the composition of the present invention is not particularly limited, a method of dry blending the three, a method of dry blending a pulverized product of each resin, or a pellet after blending the above composition There is a method to make it.

As a blending means of each component for obtaining the composition of the present invention, a ribbon blender, a high speed mixer,
A kneader, a mixing roll, an extruder, an intensive mixer, etc. are illustrated.

In the present invention, by using the modified polyolefin resin (C), the polyolefin resin (A)
And the mechanism for significantly improving the compatibility of the melt-molded EVOH (B) with each other and preventing the intra-layer peeling are not clear, but the rheological effect in the melt system of the polyolefin resin, EVOH and modified polyolefin resin, It is presumed that the recurrent effect effectively acts in a state where the dispersion action and the like are complicatedly combined.

Further, the resin composition of the present invention may be blended with other conventional additives such as polyolefin. Examples of such additives include antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, and other polymer compounds, which are used in the invention. It can be blended within a range in which the action and effect are not impaired. Specific examples of the additives include the following. Antioxidant: 2,5-di-t-butylhydroquinone,
2,6-di-t-butyl-p-cresol, 4,4'-
Thiobis- (6-t-butylphenol), 2,2'-
Methylene-bis- (4-methyl-6-t-butylphenol), octadecyl-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate,
4,4'-thiobis- (6-t-butylphenol),
Basic magnesium, aluminum, hydroxy,
Carbonate hydrates (hydrotalcite compounds), etc. UV absorber: ethylene-2-cyano-3,3'-diphenyl acrylate, 2- (2'-hydroxy-5'-
Methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl)
5-chlorobenzotriazole, 2-hydroxy-4-
Methoxybenzophenone, 2,2'-dihydroxy-4
-Methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and the like. Plasticizer: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate ester, etc. Antistatic agent: pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyophine, polyethylene oxide, carbowax, etc. Lubricants: ethylene bis stearamide, butyl stearate, etc. Coloring agent: carbon black, phthalocyanine, quinacridone, indoline, azo pigment, titanium oxide, red iron oxide, etc. Filler: glass fiber, asbestos, mica, ballastonite, calcium silicate, aluminum silicate,
Calcium carbonate, etc. Also, many other polymer compounds can be blended to the extent that the effects of the present invention are not impaired.

The resin composition of the present invention is formed into a film using a well-known melt extrusion molding machine, compression molding machine, transfer molding machine, injection molding, blow molding machine, thermoforming machine, rotational molding machine, dip molding machine, or the like. The effect can be obtained by molding into any molded product such as a sheet, a tube, a bottle, and a cup.

The resin composition of the present invention may have an arbitrary layer structure of two or more layers when it is used as a single layer of a multi-layer body in addition to being used as a single layer. As a suitable example, when the resin composition of the present invention is represented by P, the polyolefin resin is represented by A, EVOH is represented by B, and the adhesive is represented by AD, the following layer constitution is obtained. Here, it is preferable to use the modified polyolefin resin (C) used in the present invention as the adhesive AD.

2 layers A / P 3 layers A / P / B, P / B / P, P / AD / B 4 layers P / B / AD / A, A / P / AD / B 5 layers P / AD / B / AD / P, A / P / B / AD /
A, A / P / B / P / A 6 layers A / P / AD / B / AD / A 7 layers A / P / AD / B / AD / P / A

In such a multi-layer structure, the resin composition of the present invention may be replaced with scraps of the multi-layer structure. It is also possible to mix and use scraps of other polyolefin moldings.

As the multilayer molding method, a co-extrusion molding method, a co-injection molding method, a co-extrusion blow molding method or the like is used. Alternatively, a multi-layer molding method such as extrusion coating or dry lamination may be adopted. Hereinafter, description will be made with reference to examples. The parts mean parts by weight.

[0025]

【Example】

Examples 1 to 3 Polyolefin resin (A) (MFR 5.0 g / 10 minutes,
JISK6760, high density polyethylene), EXOH resin (B) (ethylene content 44 mol%, saponification degree 99.
9%, MFR 5.5 g / 10 min), maleic anhydride modified polyethylene resin (C) (MFR 1.2 g / 10 min, J
ISK6760), and after dry blending with the blending ratio shown in Table 1, pellets (P) of the resin composition were formed by an extruder having a full flight type screw having a diameter of 40 mm, L / D = 24 and a compression ratio of 3.8. Obtained.

This pellet (P) has a diameter of 20 mm and L /
A film having a thickness of 500 μ was obtained by using an extruder having a screw of D = 20 and a flat die having a width of 300 mm. Oxygen gas permeation rate (Modern) of the obtained film
Control OX-TRAN 10-50A type,
Measurement conditions 20 ° C * 65% RH), tensile rupture strength / elongation (JISK6760), constant strain environmental stress crack test (J
ISK6760 reagent 10% solution) was measured, and the results are shown in Table 1. Next, the inner and outer layers are made of low density polyethylene resin (M
FR2.1 g / 10 minutes, JISK6760), and a 2 type / 3 type coextruded film in which the intermediate layer is the resin composition (P) was produced. The inner and outer low density polyethylene layers are 45m in diameter
m, L / D = 22 screw extruder, intermediate layer resin composition (P) has a diameter of 35 mm, L / D = 23 screw extruder having a width of 550 mm and using a 2 type 3 type die. Coextrusion was performed to obtain a coextruded film having a resin composition (P) thickness of 100 μ and inner and outer layers of 100 μ each and a total thickness of 300 μ. The adhesive force (180 degree peeling, pulling speed 50 mm / min) between the outer layer and the intermediate layer of the obtained co-extruded film was measured. The results are shown in Table 1.

Comparative Example 1 High density polyethylene (MFR 5g / 10 minutes, JISK6
760) was obtained by the method of Examples 1 to 3 to obtain a film having a thickness of 500 μ. Oxygen gas permeation amount, tensile rupture strength / elongation, constant strain environmental stress crack test were measured, and the results are shown in Table 1.
In addition, the adhesive strength is low density polyethylene resin (MFR
JISK 6760, 2.1 g / 10 min), middle layer is high density polyethylene resin (MFR 5.0 g / 10 min, J
ISK6760) was used to prepare a coextrusion film in the same manner as in Examples 1 to 3, and the adhesive force between the outer layer and the intermediate layer was measured. The results are shown in Table 1.

Comparative Example 2 An EVOH resin (A) having an ethylene content of 44 mol%, a saponification degree of 99.9% and an MFR of 5.5 g / 10 min) was used to obtain a film having a thickness of 500 μ. Table 1 shows the oxygen gas permeation amount, tensile breaking strength / elongation, and constant strain environmental stress cracking resistance of the obtained film. Next, a coextruded film was obtained under the same conditions as in Examples 1 to 3 except that EVOH resin (A) was used instead of the resin composition (P) of the intermediate layer in Examples 1 to 3. The adhesive strength between the outer layer and the intermediate layer of the obtained coextruded film is shown in Table 1.

[0029]

INDUSTRIAL APPLICABILITY The resin composition of the present invention is a composition having excellent gas permeation resistance and no intra-layer peeling property, good environmental stress crack resistance, and excellent adhesiveness in the polyolefin resin. There is.

[Table 1]

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[Procedure amendment]

[Submission date] November 4, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

Examples Examples 1 to 3 Polyolefin resin (A) (MFR 5.0 g / 10 minutes,
JISK6760, high density polyethylene), EVOH resin (B) (ethylene content 44 mol%, degree of saponification 99.
9%, MFR 5.5 g / 10 min), maleic anhydride modified polyethylene resin (C) (MFR 1.2 g / 10 min, J
ISK6760), and after dry blending with the blending ratio shown in Table 1, pellets (P) of the resin composition were formed by an extruder having a full flight type screw having a diameter of 40 mm, L / D = 24 and a compression ratio of 3.8. Obtained.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Comparative Example 2 An EVOH resin (A) having an ethylene content of 44 mol%, a saponification degree of 99.9% and an MFR of 5.5 g / 10 min) was used to obtain a film having a thickness of 500 μ. Table 1 shows the oxygen gas permeation amount, tensile breaking strength / elongation, and constant strain environmental stress cracking resistance of the obtained film. Next, a coextruded film was obtained under the same conditions as in Examples 1 to 3 except that EVOH resin (A) was used instead of the resin composition (P) of the intermediate layer in Examples 1 to 3. Table 1 shows the adhesive force between the outer layer and the intermediate layer of the obtained coextruded film.

[Table 1]

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Claims (2)

[Claims] 1. (A) 5 to 80% by weight of a polyolefin resin, (B) 10 to 90% by weight of an ethylene-vinyl alcohol copolymer resin having an ethylene content of 35 to 65 mol%, and (C) an unsaturated carboxylic acid. Or 10 to 90% by weight of a polyolefin resin modified with a derivative thereof, and a melt flow rate (MFR) of (A)
(Value measured at a temperature of 190 ° C. and a load of 2160 g) 1
A resin composition having an MFR of 30 g / 10 minutes, an MFR of 1 to 100 g / 10 minutes and a MFR of (C) of 0.5 to 30 g / 10 minutes. 2. The MFR of the resin composition is the resin (A),
The resin composition according to claim 1, which is smaller than a logarithmic average MFR value obtained by a blending ratio of (B) and (C).