JPH0623275B2 - Composition - Google Patents

Description

Detailed Description of the Invention A. TECHNICAL FIELD OF THE INVENTION The present invention relates to a composition in which the compatibility between polyolefin and a saponified ethylene-vinyl acetate copolymer is significantly improved.

B. Prior Art and Problems Thereof A blend composition of polyolefin and a saponified product of an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVOH) has characteristic physical properties. In particular, in the multilayer coextrusion molding of polyolefin and EVOH, a layer of the blend composition may be used instead of the polyolefin layer or the EVOH layer, or a layer of the blend composition may be provided between the polyolefin and the EVOH layer. Therefore, the interlayer adhesion can be improved. The characteristics of such a blend composition of polyolefin and EVOH have been known in the past, but this composition is generally poor in compatibility, and when a film, sheet, bottle or the like is formed by extrusion molding, non-uniform phase separation occurs. It is known that foreign matter is liable to be generated, and especially when the vehicle is operated for a long time, the foreign matter is increased and the appearance is significantly impaired. Thus, it was the actual situation that extrusion molding of a blended composition of polyolefin and EVOH could not be practically carried out at all, or could be operated only for a short time in many cases.

C. Structure, purpose and effect of the present invention The present inventors have investigated various methods for eliminating such poor compatibility and obtaining a molded article having a beautiful appearance, and as a result, the polyolefin (A) and EVOH (B) were cyclically added. Table I, II and
When an oxide and / or a fatty acid salt (C) of at least one metal selected from Group III is contained in an appropriate amount and molding is performed using this composition, polyolefin and EVOH are added.
The present invention has been completed by discovering that the compatibility with the above is remarkably improved, a molded product having a beautiful appearance and excellent physical properties can be obtained.

D. More Detailed Description of the Invention The polyolefin (A) referred to in the present invention is high density, medium density or low density polyethylene, vinyl acetate, acrylate ester, butene, hexene, 4-metel-
Polyethylene copolymerized with α-olefins such as 1-pentene, ionomer resin, polypropylene homopolymer, polypropylene grafted with ethylene, or ethylene, butene, hexene, 4-methyl-1-
Polypropylene copolymerized with α-olefins such as pentene, modified polypropylene blended with a rubber polymer, poly 1-butene, poly 4-methyl-1-pentene, or modified polyolefin obtained by reacting the above-mentioned polyolefin with maleic anhydride. Etc. are included. Of these, polypropylene resins are particularly poor in compatibility with EVOH, and are important in that the effects of the present invention are particularly remarkable.

Further, the saponified product of ethylene-vinyl acetate copolymer (EVOH) (B) referred to in the present invention includes any substance as long as it hydrolyzes vinyl acetate units in a copolymer of ethylene and vinyl acetate. However, those having poor compatibility with polyolefin have relatively few ethylene units and a high degree of saponification (hydrolysis) of vinyl acetate units. In particular, those having ethylene unit content of 20 to 50 mol% and saponification degree of vinyl acetate unit of 96 mol% or more, particularly 99 mol% or more, have the highest gas barrier property against gases such as oxygen among thermoplastic resins. Since it is at a standard level and excellent containers can be obtained by using it in combination with polyolefin,
It is particularly important as an application target of the present invention.

Further, as the oxide and / or fatty acid salt (C) of at least one metal selected from Group I, Group II and Group III of the Periodic Table, which constitutes the composition of the present invention, there are many compounds, In particular, oxides of calcium oxide, magnesium oxide, barium oxide, zinc oxide and the like, and metal (group I, group II or group III) salts of fatty acids are mentioned.
Among these compounds, magnesium, calcium,
It has been found that oxides and / or fatty acid salts of metals of Group II of the Periodic Table, such as zinc, act particularly effectively.
Examples of fatty acids of 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. To be Of these, 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 admixture of two or more, and not only improve the compatibility between EVOH and polyolefin, but also improve the hue of the resulting molded article.

The amounts of the components (A), (B) and (C) constituting the composition of the present invention are not particularly limited, and can be arbitrarily selected according to the purpose.
However, from a practical point of view, polyolefin (A) and EVO
As for the composition ratio of H (B), a composition having a large amount of one of the resins is particularly important in that characteristic physical properties such as mechanical properties and gas barrier properties are exhibited. As a composition containing a large amount of polyolefin, the weight ratio of polyolefin (A): EVOH (B) is 80:20 to 99.9: 0.1, and particularly 90:10 to 99.7:
In the case of a composition containing a large amount of EVOH, a weight ratio of polyolefin (A): EVOH (B) in the range of 5:95 to 30:70 is particularly preferable in terms of the effect of the present invention. It can be said to be important. In addition, the amount of the metal oxide and / or fatty acid salt (C) of Group I, II or III of the Periodic Table, which improves the compatibility, has the effect of improving the compatibility depending on the type of the (C) component. Although it is adjusted within a range that does not impair the physical properties of the composition, such as mechanical properties, transparency, and gas barrier properties, the amount is often polyolefin.
To the total weight of (A) and EVOH (B) (A + B) 100 parts
It is used in the range of 0.00001 to 10 parts, especially 0.0001 to 1 part. If it exceeds 10 parts, physical properties other than compatibility are impaired, and it is often undesirable. Further, when the component (C) is blended with EVOH, the use effect tends to be high. In this case, 100 parts of EVOH and 0.002 to 0.5 parts of the component (C) are blended. The effect of improving the compatibility in the melt molding of the composition containing 0.5 part of this compound and 99.5 parts of polyolefin is remarkable. In this case, the amount of the component (C) is 0.00001 to 0.0025 part with respect to 100 parts by weight of the total weight of polyolefin and EVOH. The amount of component (C) is 0.00001
If it is less than the part, the effect is generally small. Thus, when the component (C) is blended with EVOH, the amount added is apparently small, but the blending method for obtaining the composition of the present invention is not particularly limited, and a method of dry blending the three Alternatively, a method in which the component (C) is pre-blended with all or part of polyolefin or EVOH is arbitrarily selected according to the purpose. Generally, in addition to the method of blending with EVOH as described above, the effect of improving the compatibility can be remarkably remarkably obtained by combining the method of blending with dry blend or with polyolefin.

In the present invention, the mechanism by which the oxide and / or fatty acid salt (C) of a metal of Group I, II or III of the Periodic Table significantly improves the compatibility of the polyolefin and EVOH in melt molding is sufficiently clear. is not. Just EV
Addition of a titanium (Ti) compound, which is a catalyst residue contained in a polypropylene resin, which is particularly incompatible with OH, to EVOH promotes alteration of EVOH, and the compatibility improving compound shown in the present invention with the Ti compound is promoted. It has been found by the present inventors that addition to EVOH at the same time can prevent deterioration of EVOH. Thus, in the mixed system of polypropylene resin and EVOH, the Ti compound is
It can be presumed that the mechanism that the component (C) used in the present invention inhibits this action of the Ti compound by causing a significant incompatibility. However, similar incompatibility is also observed in a mixed system of polyolefin and EVOH containing no Ti compound, and the compound shown in the present invention has an effect of improving this compatibility. It is presumed to be a complex combination of rheological effects in the molten system of polyolefin and EVOH, chemical action of impurities, etc., rather than having generality.

Other conventional additives may be added to the polyolefins for the composition of the present invention. Examples of such additives include 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) etc.},
UV absorber {ethyl-2-cyano-3,3-diphenyl acrylate, 2- (2'-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxy-4-octoxybenzophenone, etc.}, plasticizer ( Dimethyl phthalate, diethyl phthalate, wax, liquid paraffin, phosphate ester, etc., antistatic agent (pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbon wax, etc.), lubricant (ethylene) Bis stearamide, butyl stearate, etc.), colorant (carbon black, phthalocyanine, quinacridone, indoline, azo pigment, titanium oxide, red iron oxide, etc.), filler (grass 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.

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

The resin composition of the present invention can be molded into an arbitrary molded article such as a film, a sheet, a tube or a bottle by using a well-known melt extruder. The extrusion temperature at the time of molding is appropriately selected depending on the properties of the extruder, the molecular weight of the resin, the blending ratio, etc., but in most cases it is in the range of 170 ° to 300 ° C. Further, as described above, the resin composition of the present invention exerts particularly remarkable characteristics when used as one layer of a multilayer material, and the polyolefin layer is P, the EVOH layer is E, and the adhesive resin layer is D. When 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 large content of EVOH), F / D / E, F / D / E
/ D / F, P / E / P / F, P / F / D / E / D / F /
When taking a layered structure such as P, P / F / D / E / D / P,
It is possible to obtain a beautiful molded product having a high interlayer adhesion and good compatibility. In such a multilayer molding material, the blend composition of the present invention may be substituted by a scrap of the multilayer molding material. As a multi-layer molding method, generally, the number of extruders corresponding to the type of resin layer is used, and the flow of molten resin in the extruder is co-extruded in a layered form, so-called co-extrusion molding. Manufactured by. As another method, a method of molding by extrusion coating can also be adopted. Thus, the molded product obtained from the composition of the present invention has not only a uniform blended composition layer and a beautiful appearance, but also good compatibility and uniform properties, and therefore is excellent in strength. It is obtained, and its industrial significance is great.

Hereinafter, the present invention will be described more specifically by way of examples. The parts mean parts by weight.

Examples 1 to 6 Polypropylene resin (PP) {melt flow index (ASTM-D1238, 230 ° C) 0.5 g / 10 minutes, containing Ti compound as catalyst residue} (A), EVOH {content of ethylene unit 33 Mol%, saponification degree 99.9 mol%, melt index (190 ° C., 2160 g) 1.5 g / 10 min} (B) and metal oxide or fatty acid salt (C) were dry blended in the proportions shown in Table 1, Charged into an extruder having a full flight type screw with a diameter of 40 mm, L / D = 24 and a compression ratio of 3.8, width 55
Film formation was performed using a 0 mm flat die. The film forming temperature was 190 ° C to 230 ° C for the extruder, 220 ° C for the die, and the thickness was 5
A 0 μ film was wound by a take-up machine and continuously operated for 6 hours. First evaluation of the film surface condition of the obtained film
It is also shown in the table.

Comparative Example 1 A polypropylene resin and E were prepared in the same manner as in Example 1 except that magnesium stearate was not mixed.
Film formation of a VOH mixture was performed. Around 30 minutes after the start of operation, a large number of non-uniform phase-separated foreign matters which were not found in Example 1 were observed, the number increased with the passage of time, and the appearance of the obtained film was extremely poor.

Example 7 Polypropylene resin (A) having a melt flow index of 0.5 g / 10 min, ethylene unit content of 32.5 mol%, saponification degree of 99.9 mol%, melt index of 1.4 g / 10 min EV
OH (B), calcium stearate (C) and modified polypropylene adhesive resin (ADMER manufactured by Mitsui Petrochemical
QF-500) (D) and titanium oxide (G) are A: B: C:
D: G = 97.4: 0.5: 0.1: 1: 1 blend product
Created (F). This blend (F) and the EVO described above
Charge H (B) and adhesive resin (D) into separate extruders and use F / D
/ B / D / F (thickness ratio 15: 1: 1: 1: 15) was co-extruded with 5 layers of 3 types to obtain a sheet. For extrusion molding, B and D are 50mm in diameter, L / D = 25 uniaxial screw extruder is used for the temperature of 180 ° ~ 215 ° C, F is 100mm in diameter and L / D = 22 screws are equipped. The same direction rotary mesh type twin-screw extruder is set to the temperature of 180-220 ℃, and the feed block type die (width 1000mm) is set to 225 ℃.
A sheet of 000μ was obtained. A good sheet was obtained even after continuous operation for 24 hours, and no phase-separated foreign matter with poor compatibility was observed.

Comparative Example 2 A sheet was obtained by carrying out coextrusion molding in the same manner as in Example 7 except that calcium stearate (C) was not used. Around 1 hour after the start of operation, a large number of non-uniform phase-separated foreign matters that were not seen in Example 7 were observed, the number increased with the passage of time, and the appearance of the obtained sheet was extremely poor.

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Claims (5)

[Claims] 1. (A) Polyolefin, (B) Saponified product of ethylene-vinyl acetate copolymer, and (C) Oxide of at least one metal selected from Group I, Group II and Group III of the periodic table, and / or A composition comprising a fatty acid salt and containing the component (C) in an amount of 0.00001 to 10 parts based on 100 parts by weight of the resins (A) and (B). 2. The composition according to claim 1, wherein the polyolefin (A) is a polypropylene resin. 3. Saponified ethylene-vinyl acetate copolymer (B)
The composition according to claim 1 or 2, wherein the content of ethylene units is 20 to 50 mol% and the degree of saponification of vinyl acetate units is 96% or more. 4. The fatty acid metal salt of component (C) has 8 to 22 carbon atoms.
The composition according to any one of claims 1 to 3, which is a higher fatty acid metal salt in the range. 5. The weight ratio of polyolefin (A): saponified ethylene-vinyl acetate copolymer (B) is 80:20 to 99.9: 0.1, and the weight ratio is 80:20 to 99.9: 0.1. The composition according to the section.