JP2604572B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a composition in which the compatibility between a polyamide resin and a saponified ethylene-vinyl acetate copolymer is remarkably improved.

[0002]

2. Description of the Related Art A blend composition of a saponified ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVOH) and a polyamide resin has characteristic physical properties. In particular, at the time of multilayer coextrusion molding of various thermoplastic resins and EVOH, instead of the thermoplastic resin layer or the EVOH layer,
The interlayer adhesion can be improved by using the blend composition or by providing a layer of the blend composition between the thermoplastic resin and the EVOH layer.
Further, a molded product such as a film, a sheet or a bottle obtained by subjecting the blend composition alone to melt extrusion molding and further stretching and / or heat-treating as necessary has excellent gas barrier properties and mechanical properties. As described above, the characteristics of the blend composition of a polyamide resin and EVOH have been conventionally known, but this composition cannot be said to have good compatibility.
It is known that when a film, sheet, bottle, or the like is formed by extrusion, non-uniform phase-separated foreign matter is likely to be generated. In particular, the long-term operation increases the foreign matter and significantly impairs the appearance. Thus, polyamide resin and EVO
Despite the excellent characteristics of the H blend composition, extruding cannot be practically performed at all, or it can be operated only for a short time if possible.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate such poor compatibility, and an object of the present invention is to obtain a molded article having a beautiful appearance.

[0004]

The object of the present invention is to provide (A) a polyamide resin, (B) 20 to 50 mol% of ethylene units,
A saponified ethylene-vinyl acetate copolymer having a degree of saponification of vinyl acetate units of 96% or more, and (C) a fatty acid salt of at least one metal selected from Groups I, II and III of the Periodic Table, and The mixing ratio of the resin (A) and the resin (B) is 1:99 to 40:60 (weight ratio),
The above component (C) is added to the sum of the weights of the above resins (A) and (B) by 1
This is achieved by providing a resin composition containing 0.00001 to 10 parts with respect to 00 parts. When molded using this composition, the compatibility between the polyamide resin and EVOH is remarkably improved, the appearance is beautiful, and a co-extruded product having high interlayer adhesion, or excellent in gas barrier properties and mechanical properties. A molded article is obtained.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, polyamide resins such as polycapramide (nylon-6) and poly-ω
-Aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylaurinlactam (nylon-12), polyethylenediamine adipamide (nylon-2, 6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sebacamide (nylon-6,10), polyhexamethylene dodecamide (Nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,6), polydecamethylene sebacamide (nylon-10,8), Alternatively, caprolactam / laurin lactam copolymer, caprolactam / hexamethylene diammonium adipate Preparative copolymer, laurolactam /
Hexamethylene diammonium adipate copolymer, hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer, ethylene diammonium adipate / hexamethylene diammonium adipate copolymer, caprolactam / hexamethylene diammonium adipate / hexamethylene di Ammonium sebacate copolymer, and the like. Among them, a caprolactam / hexamethylenediammonium adipate copolymer (nylon-6 / 66) is particularly excellent in physical properties of a blend with EVOH, and is particularly important in practical use.

[0006] The saponified ethylene-vinyl acetate copolymer (EVOH) (B) referred to in the present invention may be any one obtained by hydrolyzing a vinyl acetate unit in a copolymer of ethylene and vinyl acetate. Those having poor compatibility with the polyamide resin have relatively few ethylene units and high saponification degree (hydrolysis degree) of vinyl acetate units. In particular, the content of ethylene units is 20 to 50.
When the saponification degree of vinyl acetate unit is 96% or more, especially 99% or more, the gas barrier property against gas such as oxygen is the highest level among thermoplastic resins, and is used in combination with polyolefin. This is particularly important as an object to which the present invention is applied, because excellent containers can be obtained.

Further, as the fatty acid salt (C) of at least one metal selected from Group I, Group II and Group III of the periodic table constituting the composition of the present invention, many compounds can be mentioned. It has been found that fatty acid salts of metals belonging to Group II of the periodic table, such as magnesium, calcium and zinc, tend to work particularly effectively. Fatty acids constituting metal (Group I, Group II or Group III) salts of fatty acids include lower fatty acids such as acetic acid, propionic acid, butyric acid, caproic acid, and caprylic acid; and higher fatty acids such as lauric acid, stearic acid, and myristic acid. Is mentioned. Among them, metal salts of higher fatty acids having 8 to 22 carbon atoms, especially calcium salts,
Magnesium salts and zinc salts are particularly suitable for the purpose of the present invention. These components (C) are used alone or in combination of two or more.

The composition ratio of the polyamide resin (A) and EVOH (B) constituting the composition of the present invention is 1:99 to 4 as a weight ratio of the polyamide resin (A): EVOH (B).
The ratio is preferably 0:60, and more preferably 5:95 to 30:70. 1% by weight of polyamide resin (A)
In the following, the effect of improving the mechanical properties of the EVOH resin, for example, the effect of imparting flexibility cannot be obtained, and the polyamide resin (A)
If the content is 40% by weight or more, the gas barrier property is significantly reduced.

Further, a fatty acid salt (C) for improving the compatibility
Depending on the type of the components (A), (B) and (C), the effect of improving the compatibility can be obtained and the physical properties of the composition such as mechanical properties, transparency and gas barrier properties are not impaired. It is adjusted in the range, but in many cases, the amount is the sum of the weight of the polyamide resin (A) and the EVOH (B) (A + B) 10.
0.00001 to 10 parts, particularly 0.0
It is used in the range of 001 to 1 part. If it exceeds 10 parts, physical properties other than compatibility are likely to be impaired, which is not preferable in many cases.

When the component (C) is previously blended with the polyamide resin and / or EVOH, the use effect tends to be high. As an example of blending in EVOH, the component (C) is added in an amount of 0.002 to 100 parts of EVOH.
0.5 parts by weight. This formulation 0.
The effect of improving the compatibility in melt molding of a composition containing 5 parts and 99.5 parts of a polyamide resin is remarkable. In this case, the amount of the component (C) is 0.00001 to 0.0025 per 100 parts by weight of the total weight of the polyamide resin and the EVOH.
Department. When the amount of the component (C) is less than 0.00001 parts, the effect is generally small. Thus, (C)
When the components are blended with EVOH, the effect can be said to be large even if the added amount is apparently small.

The blending method for obtaining the composition of the present invention is not particularly limited, and a method of dry-blending the three components,
Alternatively, the component (C) is a polyamide resin or EVOH
Of the above (A), (B) and (C) depending on the purpose. Arbitrarily selected. In general, in addition to the above-described method of blending with EVOH, a particularly remarkable effect of improving the compatibility can be obtained by combining a method of dry blending or a method of blending in advance with a polyamide resin. .

In the present invention, the mechanism by which the fatty acid salt (C) of a metal belonging to Group I, II or III of the Periodic Table significantly improves the compatibility of the polyamide resin and EVOH in melt molding is sufficiently clear. However, it is presumed that the component (C) is effectively acting in a state where the rheological effect and the chemical action of impurities in the molten system of the polyamide resin and EVOH are combined in a complicated manner.

The resin composition of the present invention may contain other conventional additives in the thermoplastic resin. Examples of such additives include antioxidants, ultraviolet absorbers,
Plasticizers, antistatic agents, lubricants, coloring agents, fillers, and other high molecular compounds can be used, and these can be blended as long as the effects of the present invention are not impaired. Specific examples of the additives include the following.

Antioxidants: 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) and the like. UV absorber: ethyl-2-cyano-
3,3-diphenyl acrylate, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole,
-(2'hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotrial, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2- Hydroxy-4-octoxybenzophenone and the like. Plasticizer: dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate ester and the like. Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbowax and the like. Lubricants: ethylene bis stearamide, butyl stearate and the like. Coloring agents: carbo black, phthalocyanine, quinacridone, indoline, azo pigments, titanium oxide, red iron oxide and the like. Filler: glass fiber, asbestos, mica, ballastonite, calcium silicate, aluminum silicate, calcium carbonate, etc.

Examples of the means for compounding the components for obtaining the composition of the present invention include a ribbon blender, a high-speed mixer, a co-kneader, a mixing roll, an extruder, and an intensive mixer.

The resin composition of the present invention can be prepared by a known melt extrusion molding machine, compression molding machine, transfer molding machine, injection molding machine,
Using a blow molding machine, a thermoforming machine, a rotary molding machine, a dip molding machine, or the like, it can be molded into an arbitrary molded product such as a film, a sheet, a tube, and a bottle. The extrusion temperature during molding is appropriately selected depending on the type and molecular weight of the resin, the compounding ratio of the composition, the properties of the extruder, and the like, but in most cases is in the range of 170 to 350 ° C.

As described above, when the resin composition of the present invention is used as one layer of a multilayer material, it exhibits a unique feature in terms of adhesiveness. Is E, the adhesive resin layer is D, and the layer of the composition of the present invention is F. E / F / E, F / E / F, F / F
/ F (F in the intermediate layer has a high EVOH content), F / D /
E, F / D / E / D / F, P / E / P / F, P / F / D
When a layer structure such as / E / D / F / P and P / F / D / E / D / P is adopted, a beautiful molded product having high interlayer adhesion and excellent compatibility can be obtained. In such a multilayer molding, the blend composition of the present invention can be replaced with scrap of a multilayer molding.

As a multilayer molding method, generally, a number of extruders corresponding to the type of the resin layer are used, and a flow of the resin melted in the extruder is simultaneously extruded in a superposed layer state. It is performed by so-called coextrusion molding. As another method, a multilayer molding method such as extrusion coating and dry lamination may be employed.
Further, by performing stretching such as uniaxial stretching, biaxial stretching or blow stretching of a single molded article of the composition of the present invention or a multilayer molded article containing the composition of the present invention, mechanical properties, gas barrier properties, etc. In addition, it is possible to obtain a molded product having more characteristic physical properties. Thus, the molded product obtained from the composition of the present invention not only has a uniform and beautiful appearance of the blend composition, but also has excellent excellent properties such as strength properties and gas barrier properties due to good and uniform compatibility. And its industrial significance is great. Hereinafter, the present invention will be described more specifically with reference to examples. Parts mean parts by weight.

[0019]

【Example】

Example 1 6/66 copolymer polyamide (66 component 15%, melting point 19)
8 ° C.) 10 parts, EVOH [ethylene unit content 33 mol%, saponification degree 99.9%, melt index (190
90 ° C., 2160 g) 1.5 g / 10 min], and 90 parts of magnesium stearate and 0.03 part of magnesium stearate, and then has a full flight screw having a diameter of 40 mm, L / D = 24, and a compression ratio of 3.8. The film was charged into an extruder, and a film was formed using a flat die having a width of 550 mm.
The film forming temperature is 190 ° to 240 ° C. for the extruder and 225 for the die.
° C, a film having a thickness of 100 µ was wound up by a take-up machine, and a continuous operation was performed for 6 hours. The obtained film showed uniform and good compatibility, and a little phase-separated foreign matter having poor compatibility was observed. A 90-mm square test piece of the obtained film was heated at 85 ° C. for 1 minute using a biaxial stretching test apparatus (manufactured by Toyo Seiki Seisaku-sho, Ltd.), and then tripled both vertically and horizontally at a stretching speed of 5 m / min. Stretched. The stretching was carried out uniformly, and this stretched film was fixed to a wooden frame and heat-treated at 110 ° C. in a hot air drier, whereby a good film having excellent strength and gas barrier properties was obtained.

Comparative Example 1 A film of a mixture of polyamide and EVOH was formed in the same manner as in Example 1 except that magnesium stearate was not mixed. Around 30 minutes after the start of the operation, a large number of non-uniform phase-separated foreign substances not observed in Example 1 were observed, and the number increased over time, and the appearance of the obtained film was extremely poor.

Example 2 The 6/66 copolymer polyamide (PA) shown in Example 1,
After EVOH and various components (C) were dry-blended at the ratios shown in Table 1, extrusion film formation was carried out in the same manner as in Example 1. The evaluation of the film surface state of the obtained film is shown in Table 1.

[0022]

[Table 1]

Note 1) The state of the film surface was evaluated according to the following criteria. Shu: Shows uniform and good compatibility and shows no phase-separated foreign matter. Excellent: Shows uniform and good compatibility, but a small amount of small phase-separated foreign matter is observed in long-time molding. Good: The compatibility is good, but some phase-separated foreign matters are slightly observed. Acceptable: The effect of improving compatibility was observed, but the content of phase-separated foreign matters was slightly observed.

[0024]

According to the present invention, the compatibility between the polyamide resin and EVOH is remarkably improved, and the obtained molded product has a beautiful appearance and excellent gas barrier properties.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication (C08L 29/04 77:00)

Claims (1)

(57) [Claims] 1. A (A) polyamide resin, (B) a saponification degree of 20 to 50 mol% of ethylene units and a vinyl acetate unit of 96.
% Or more of a saponified ethylene-vinyl acetate copolymer and (C) a fatty acid salt of at least one metal selected from Groups I, II and III of the Periodic Table, and the above resin (A) and the above resin The compounding ratio with (B) is 1: 99-4.
0:60 (weight ratio), and the above component (C) was added in an amount of 0.00000 with respect to 100 parts of the sum of the weights of the resins (A) and (B).
A resin composition containing 1 to 10 parts.