JPH0715035B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is to provide a resin composition mainly composed of a saponified ethylene-vinyl acetate copolymer resin and having excellent impact resistance.

B. Prior art and its problems The saponified ethylene-vinyl acetate copolymer resin with an ethylene content of 20 to 55 mol% and a saponification degree of 90% or more is more oil resistant, rigid, harder and abrasion resistant than other resins. It is a thermoplastic resin having extremely good properties and is used as a molded product such as a film, a sheet or a bottle as a resin excellent in gas barrier property. However, this resin has poor impact resistance and is hard and brittle. Conventionally, a method of blending a rubber-like substance is known as a method for improving impact resistance of an ethylene-vinyl acetate copolymer saponified resin, and one of them is known as an ethylene-vinyl acetate copolymer resin or ethylene-acrylic acid. A method of blending an ester copolymer resin is well known, and a method of blending both the resin and an ethylenically unsaturated carboxylic acid or a resin obtained by grafting the carboxylic acid anhydride has also been tried. , This composition generally has poor homogeneity and moldability,
When a film, sheet or bottle is formed by extrusion molding, nonuniform phase-separated foreign matter is generated, or a resin, particularly an ethylene-vinyl acetate copolymer saponified resin, is liable to be insoluble and a gel-like substance is liable to be generated, especially for a long time. It is known that the operation increases the amount of foreign matter and impairs the appearance of the molded product. Thus, a blend composition of various rubber-like resins and an ethylene-vinyl acetate copolymer saponified resin, despite its excellent characteristics, cannot be extruded practically at all, or even if it is possible, it can be done in a very short time. The reality was that I could only drive.

C. Problems to be Solved by the Present Invention The present invention aims to eliminate such uniform mixing defects and moldability defects and to bring out the excellent characteristics of such a blend composition into practical use. Moreover, it is intended to obtain a molded article having excellent impact resistance.

D. Means for Solving the Problem In the present invention, (A) an ethylenically unsaturated carboxylic acid or said carboxylic anhydride is grafted onto a polyethylene polymer having a density of 0.91 to 0.86 g / cm ³ to obtain an ethylenically unsaturated 0.02 to 0.3 equivalent of a metal compound consisting of a hydroxide or carbonate of a metal of Group Ia of the periodic table with respect to the carboxylic acid or the carboxylic anhydride component, or the metal compound and the density of 0.91 ~ A mixture containing 0.86 g / cm ³ of a polyethylene-based polymer, and (B) an ethylene component content of 20 to 55
A resin composition having an impact resistance, which comprises a saponified ethylene-vinyl acetate copolymer resin having a mol% and a saponification degree of 90% or more.

E. Effect of the Invention When molded by using the resin composition of the present invention, a poor co-extrusion molding product having a uniform mixing defect and a poor moldability, a beautiful appearance, and a gas barrier property and impact resistance. A molded article having excellent properties is obtained.

F. More Detailed Description of the Present Invention The most important feature of the present invention is that a special modified copolymer resin obtained based on a polyethylene-based polymer having a density of 0.91 to 0.86 g / cm ³ is used as the component (A). is there. Density 0.91
Being large, exceeding g / cm ³ , the impact resistance, uniform mixing property and moldability which are the effects of the present invention are not sufficient, and the density is
If it is less than 0.86 g / cm ³ , the polyethylene polymer is not suitable because it cannot be passed through the manufacturing process and cannot be stably supplied industrially. To enjoy the effects of the present invention more preferably,
A polyethylene-based polymer having a density of 0.905 to 0.87 g / cm ³ is preferably used as a base. The reason is not always clear, but it is considered that the crystallinity of the resin may be involved, but the density is 0.92 g / cm ³ or more compared to the method of the present invention based on a polyethylene-based polymer. When the obtained metal-modified graft polyethylene-based polymer is used as the component (A), no remarkable improvement effect as in the present invention can be obtained, and sufficient explanation can be obtained only from the crystallinity. No, the reason is not clear. Such a remarkable effect is difficult to reach the present invention only by analogy with the prior art, and is truly surprising. The method for producing such a polyethylene-based polymer is not limited, but, for example, using a Ziegler type catalyst, a polymerization temperature of 10
There is a method of copolymerizing ethylene and α-olphine at -80 ° C. As the α-olefin, those having 3 to 8 carbon atoms are used, and for example, propylene, butene-1, hexene-
1,4-methylpentene-1, octene-1 and the like.
Further, as a third monomer, butadiene, 1,4-hexadiene, 1,5-hexadiene, vinyl norbornene,
It is also possible to copolymerize by adding various dienes such as ethylidene norbornene and dicyclopentadiene. As commercially available products, for example, Tuffmer A-4085 and Tuffmer A-409 marketed by Mitsui Petrochemical Co., Ltd.
0, Toughmer P-0180, and Toughmer P-0480 are flex resins DFDA-137NT marketed by Nippon Unicar Co., Ltd.
7, Flex Resin DFDA-1138NT, etc.

Examples of the ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride used in the graft polymerization include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic acid anhydride, itaconic acid and the like ethylenically unsaturated carboxylic acid or the carboxylic acid. Although there are anhydrides and the like, maleic anhydride is preferable among them. When maleic anhydride is used, it can be co-grafted simultaneously with a comonomer such as ethylene, styrene, vinyl acetate or vinyl ether. Graph and amount is 0.
001 to 6% by weight is sufficient, but 0.01 to 5% by weight is more preferable in terms of impact resistance, uniform mixing property and moldability.

The method of graft polymerization is not particularly limited, but an ethylene-acrylic acid ester copolymer with an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride, dibenzoyl peroxide, dibutyl peroxide, dicumyl peroxide, t- An organic peroxide such as butyl perbenzoate, t-butyl hydroperoxide, cumene hydroperoxide, etc. is allowed to coexist, and a heating reaction is carried out so that a chemical bond is generated between them. The reaction is, for example, benzene, toluene, xylene, chlorobenzene, t-butylebenzene,
100-240 ℃ in the presence or absence of solvent such as cumene
However, it is more preferable to carry out the treatment at 110 to 200 ° C. in the presence of a solvent such as toluene or xylene, since a uniform product can be obtained.

Examples of the metal compound consisting of a hydroxide or carbonate of a metal of Group Ia of the periodic table include sodium carbonate, lithium carbonate, sodium hydroxide, potassium hydroxide and the like. Among them, sodium carbonate, potassium hydroxide, water A metal compound of Ia of the periodic table such as sodium oxide is preferably used. In particular, metal hydroxides, especially sodium hydroxide, are particularly preferably used. The metal compound content is 0.
If the amount is less than 02 equivalents, an industrially useful molded article such as the present invention cannot be obtained, such as a wavy pattern or unevenness formed on the entire molded article. If it is compounded in excess of 0.3 equivalent, the resin composition will be colored or the fluidity will be poor, which is not preferable as a molding material.

Density of 0.91 to 0.86 g / cm ³ grafted with an ethylenically unsaturated carboxylic acid or said carboxylic anhydride in the present invention
A modified copolymer prepared by blending a polyethylene-based polymer with an ethylenically unsaturated carboxylic acid or a metal compound consisting of a metal hydroxide or carbonate of Group Ia of the periodic table with 0.02 to 0.3 equivalents relative to the carboxylic acid anhydride component. The polymer has such sufficient performance that it can be industrially used, but if necessary, the density
It can be used as a mixture with 0.91 to 0.86 g / cm ^{3 of} an ethylene polymer. In that case, the blending ratio of the graft polyethylene-based polymer and the polyethylene-based polymer depends on the characteristics of the graft polyethylene-based polymer and the polyethylene-based polymer, but it is 2:98 to 40:60 that the impact resistance is high. Good in terms of moldability and manufacturing cost.

The component (B) constituting the composition of the present invention is an ethylene-vinyl acetate copolymer saponified product having an ethylene component content of 20 to 55 mol% and a saponification degree of the vinyl acetate component of 90% or more. When the ethylene content is 20% or less, not only the moldability is deteriorated, but it is considered to be related to the increase in the rigidity of the saponified product of the ethylene-vinyl acetate copolymer, but the effect of the present invention is diminished. If the ethylene content exceeds 55 mol%, the rigidity is reduced but the gas barrier property, which is the most characteristic feature of the resin, is deteriorated and the resin becomes unsatisfactory. The ethylene-vinyl acetate copolymer saponified resin is 20 to 55 mol%
It may be a blend of two or more resins having an ethylene content in the above range and different ethylene content. The saponification degree of the vinyl acetate component of the resin is preferably 90% or more, and less than 90% is not preferable because the barrier property is lowered. Furthermore, the third component such as saponified ethylene-vinyl acetate copolymer treated with a boron compound such as boric acid or borax, a silicon-containing olefinically unsaturated monomer, α-olefin, N-vinylpyrrolidone is used as ethylene and vinyl acetate. The modified resin obtained by copolymerizing with and saponifying can also enjoy the effects of the present invention as long as it does not impair various physical properties such as melt moldability, gas barrier properties and impact resistance.

The composition of the present invention has a density (A) of 0.91 to 0.86 g / cm 3.
Grafting an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride onto the polyethylene polymer of ³ to obtain 0.02 to 0.3 equivalents of Group Ia of the periodic table with respect to the ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component. (B) an ethylene component content of 20% is obtained by blending a metal compound comprising a metal hydroxide or carbonate of the above metal compound, or a mixture of the metal compound and a polyethylene polymer having a density of 0.91 to 0.86 g / cm ^3. The blending ratio of each component of the ethylene-vinyl acetate copolymer saponified resin having a saponification degree of ˜55 mol% and a saponification degree of 90% or more can be arbitrarily selected according to the purpose. However, from a practical point of view, as the composition ratio of (A) and (B), the composition having a large amount of the resin (B) exhibits improved physical properties such as impact resistance and mechanical properties or gas barrier properties. It is particularly important in that it is done. A weight ratio of (A) :( B) of 1:99 to 50:50, especially 5:95 to 40:60, especially 10 to 30 is particularly important in terms of the effect of the present invention.

There is no particular limitation on the blending method for obtaining the composition of the present invention, a method of dry blending the two, or (A) component (B) ethylene component content of 20 to 55 mol%,
A method of preliminarily blending with a part of the saponified ethylene-vinyl acetate copolymer resin having a saponification degree of 90% or more is arbitrarily selected.

In the present invention, (A) a polyethylene polymer having a density of 0.91 to 0.86 g / cm ³ is grafted with an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride to obtain an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride component. For 0.02〜
0.3 equivalent of a metal compound consisting of a hydroxide or carbonate of a metal of Group Ia of the Periodic Table, or a polyethylene polymer having a density of 0.91 to 0.86 g / cm ³ was added to the metal compound. The mechanism by which the mixture (B) has an ethylene component content of 20 to 55 mol% and a saponification degree of 90% or more and saponified ethylene-vinyl acetate copolymer resin is significantly improved in impact resistance and moldability. However, (B) the ethylene component content is 20 to 55 mol%, the saponification resin of ethylene-vinyl acetate copolymer having a saponification degree of 90% or more, and the density constituting (A) is 0.91 to 0.86 g / cm ³ . A resin prepared by grafting an ethylenically unsaturated carboxylic acid or a carboxylic anhydride to a polyethylene polymer, or a mixture of a polyethylene polymer having a density of 0.91 to 0.86 g / cm ³ and a graft polyethylene polymer and an ethylenic graft Tiredness By mixing with 0.02 to 0.3 equivalents of a metal compound consisting of a metal hydroxide or carbonate with respect to the carboxylic acid or the carboxylic anhydride component, the rheological effect in the melting system, the chemical action of impurities, etc. are complicatedly combined. Together, it is presumed that the resulting morphological properties of the composition were in a favorable state for exerting impact resistance.

The composition of the present invention may contain other additives commonly used in thermoplastic resins. Examples of such additives include antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, wetting agents, and fillers, and they are blended within a range that does not impair the action and effect of the present invention. can do. The following are specific examples of the additive. Antioxidants: 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,
4'-thiobis- (6-t-butylphenol, 2,2'methyl-bis (4-methyl-6-t-butylphenol),
Tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, 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) -5-chlorobenzotriazole, 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 oleic acid, polyethylene oxide, carbowax, etc. Lubricant: ethylene bis stearamide,
Butyl stearate, etc. Coloring agents: carbon black, phthalocyanine, quinacridone, indoline, azo pigments, titanium oxide, red iron oxide, etc. Filler: glass fiber, asbestos, mica, ballastonite, etc.

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

The composition of the present invention is a film, sheet, etc., using a known melt extrusion molding machine, compression molding machine, transfer molding machine, injection molding machine, blow molding machine, thermoforming machine, rotational molding machine, dip molding machine, or the like. It can be molded into any molded product such as a tube, a tube and a bottle. The extrusion temperature at the time of molding is appropriately selected depending on the type of resin, the molecular weight, the compounding ratio of the composition, the properties of the extruder, and the like, but in most cases it is in the range of 170 ° C to 250 ° C. The composition of the present invention can also be used as one layer of a multi-layer structure, in which case the thermoplastic resin layer contains P, the ethylene component content is 20 to 55 mol%, and the saponification degree is 90% or more. When the combined saponified resin layer is E, the adhesive resin layer is D, and the layer of the composition of the present invention is M, P / D / M / D / P, M / E / M, M / D / E, M / D / E
/ D / M, P / D / E / D / M, P / E / P / M, P / M / D / E / D / M / P, P / M / D / E / D
A layer structure such as / P can be adopted. As a multi-layer molding method, generally, the number of extruders corresponding to the type of resin is used, and so-called co-extrusion molding is performed in which the flows of the molten resin in the extruder are simultaneously extruded in a layered state. To be done. As another method, a multi-layer molding method such as extrusion coating or dry lamination can be adopted. Further, a single molded product of the composition of the present invention or a multilayer molded product containing the composition of the present invention can be made more useful by undergoing processes such as uniaxial or biaxial stretching, deep drawing and blow molding. . The laminate obtained in the present invention can be further laminated with a synthetic resin film, metal, paper or the like. Thus, the molded product obtained from the composition of the present invention has many excellent properties such as strength physical properties and gas barrier properties because not only the blend composition is uniform and the appearance is beautiful, but also the compatibility is good and uniform. It has, and its industrial significance is truly great.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. The tests and evaluation methods in Examples and Comparative Examples are as follows.

Melt Index (MI) Using a melt indexer according to ASTM D-1238
The flow rate of the resin for 10 minutes when a load of 2160 g is applied is shown. The measurement temperature is 190 ° C.

Izod impact strength Shows notched impact strength according to ASTM D-256. The sample used was an absolutely dried sample, and the measurement was performed at 20 ° C.

G. Examples Examples 1 to 4 and Comparative Examples 1 to 5 Tuffmer A-4085 (density 0.88 g / cm ³ , MI (190 ° C, 2160
Polyethylene resin (g) was 3.6 g / 10 min, 215 parts by weight of Mitsui Petrochemical Co., Ltd.) and 1.8 parts by weight of maleic anhydride were dissolved in 648 parts by weight of purified toluene and kept at 180 ° C. 180 parts by weight of a purified toluene solution in which 25 parts by weight of maleic anhydride was dissolved was continuously added to this solution in 2.0 hours with stirring. At the same time, 100 parts by weight of a purified toluene solution in which 4.0 parts by weight of cumene hydroperoxide was dissolved was continuously added in 2 hours. After the addition was completed, the reaction was continued for 30 minutes. After cooling, the reaction solution was poured into a large amount of acetone to precipitate a polymer. The obtained polymer was purified by reprecipitation using purified toluene as a solvent and acetone as a non-solvent. This product contained 1.5% by weight of maleic anhydride component and had an MI of 2.0 g / 10 minutes.

20 parts of an aqueous solution containing a predetermined amount of sodium hydroxide (NaOH) was added uniformly to 100 parts by weight of the polymer thus obtained, and after partially drying, the volatiles were expelled under reduced pressure with a vented extruder. While melt-kneading into pellets,
A modified copolymer resin was obtained.

A predetermined amount of the adhesive resin composition obtained above was dry blended with the above-mentioned Toughmer A-4085, and then melt-kneaded into pellets with an extruder to obtain a blend composition (A).

On the other hand, by saponifying 99.6% of the vinyl acetate component of the ethylene-vinyl acetate copolymer with a vinyl acetate component content of 67 mol%, MI = 1.4 g / 10 min saponified product of the ethylene-vinyl acetate copolymer. Resin (B) was obtained.

Laboplast mill (manufactured by Toyo Seiki Co., Ltd.) was dry-blended by changing the mixing ratio of both components (A) and (B) obtained above.
Was kneaded for 20 minutes at 230 ° C. A molded product obtained by pressure molding this mixed composition in a standard mold at 220 ° C. (2.5
The Izod impact value of inch × 0.5 inch × 0.125 inch) was measured. The results are shown in Table 1.

In Examples 1 to 4 in which the amount of addition of NaOH was 0.1 equivalent, Comparative Examples 1 to 4 showed that non-colored compositions showing a high Izod impact value depending on the amount of the component (A) added were obtained.
It is easy to see in comparison with 2. In Comparative Examples 3 to 4 in which NaOH was not added, the composition was not only colored, but also had extremely poor fluidity, and was unsuitable as a molding material. When 1.0 equivalent of NaOH was added, as shown in Comparative Example 5, the modified copolymer itself was colored and the fluidity was extremely poor, and no further tests were conducted.

Comparative Example 6 Instead of Tuffmer A-4085, Mirason 12 (density 0.927 g / c
The Izod impact value was measured in the same manner as in Example 1 except that m ³ , MI = 3.0, manufactured by Mitsui Petrochemical Co., Ltd. was used. The Izod impact value is 1.9 kgcm / cm, which is extremely low.
It had no practical value.

Examples 5-6, Comparative Examples 7-11 Flex Resin DFDA-1138 in place of Toughmer A-4085.
NT (density 0.90g / cm ³ , MI (190 ℃, 2160g) 0.4g / 10min,
(Manufactured by Nippon Unicar Co., Ltd.) was used to obtain a polymer containing 1.4% by weight of a maleic anhydride component in the same manner as in Example 1 except that the amounts of maleic anhydride and cumene hydroperoxide used were changed. Furthermore, instead of NaOH, K ₂
A modified copolymer resin was obtained in the same manner as in Example 1 except that a predetermined amount of CO ₃ was used.

The modified copolymer resin obtained above and Toughmer P-0180 (density: 0.
88 g / cm ³ , M1.5, manufactured by Mitsui Petrochemical Co., Ltd.) and a predetermined amount were dry blended to obtain a component (A) resin.

On the other hand, by saponifying 99.5% of the vinyl acetate component of the ethylene-vinyl acetate copolymer having a vinyl acetate component content of 56 mol%, MI = 5.6 g / 10 min saponified product of the ethylene-vinyl acetate copolymer. Resin (B) was obtained.

Predetermined amounts of both components (A) and (B) obtained above were used to
The mixture was kneaded into pellets with an extruder equipped with a uniaxial screw with mmΦ and L / D = 25. Using this pellet, injection molding was performed at 220 ° C, and a sample for Izod impact test (2.
5 inch × 0.5 inch × 0.125 inch) was prepared and the impact strength was measured. The results are shown in Table 2.

Example 5 containing 0.05 and 0.1 equivalents of potassium carbonate
In Example 8, it is clear that excellent impact strength is obtained in the case of only the component (B) shown in Comparative Example 7 and in the example of using only Tuffmer as the component (A) shown in Comparative Example 8. is there. In Comparative Example 9 in which no potassium carbonate was used as the modified copolymer of the component (A) and Comparative Example 10 in which only 0.01 equivalent of potassium carbonate was used as the modified copolymer of the component (A), the composition was colored, and In Comparative Example 11 in which the moldability is poor, and 1.0 equivalent of potassium carbonate is added, the modified copolymer itself is colored, and the moldability is poor, and the present invention is to add potassium carbonate in a specific range. The effect of is obvious.

Claims (4)

[Claims] 1. An ethylene-based unsaturated carboxylic acid or a carboxylic acid anhydride is grafted onto a polyethylene polymer having a density (A) of 0.91 to 0.86 g / cm ³ to obtain an ethylenically unsaturated carboxylic acid or a carboxylic acid anhydride. 0.02 to 0 for product components.
A mixture containing 3 equivalents of a metal compound consisting of a hydroxide or carbonate of a metal of Group Ia of the periodic table, and (B) an ethylene component content of 20 to 55 mol% and a saponification degree (90
%) Saponified ethylene-vinyl acetate copolymer resin, and the weight ratio of (A) to (B) is 1:99 to 50:50.
Which is a resin composition having impact resistance. 2. The resin composition according to claim 1, wherein the ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride is maleic anhydride. 3. The resin composition according to claim 1 or 2, wherein the metal compound is sodium hydroxide. 4. A polyethylene-based polymer having a density of 0.91 to 0.86 g / cm ^{3 and} a polyethylene-based polymer obtained by grafting the polymer and an ethylenically unsaturated carboxylic acid or the carboxylic acid anhydride in a weight ratio of 98: 2. The resin composition according to any one of claims 1 to 3, which is blended so as to be 60:40.