JPS6231013B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyolefin composition that has excellent adhesion to saponified ethylene-vinyl acetate copolymers, nylon, polyvinyl alcohol, polyolefins, and the like. Conventionally, polyolefins such as polypropylene have good mechanical properties, transparency, moldability, and hygienic properties, so they have been used in a wide range of applications. Its use is restricted in the field of packaging materials. In order to compensate for these drawbacks of polypropylene, it is possible to laminate a film or sheet of polar resin such as saponified ethylene-vinyl acetate copolymer or nylon, which has good gas barrier properties and oil resistance, on a polypropylene film or sheet. As is known, since polypropylene is non-polar, it has low affinity with polar resins, and even if the two are melt-pressed together, adhesive strength that can withstand practical use cannot be obtained. Therefore, a well-known method is to graft an unsaturated carboxylic acid onto polypropylene in order to improve its affinity with polar substances. However, when the grafting reaction is carried out by solution polymerization, the cost is high, and in the case of thermally decomposed grafting of polypropylene, unreacted unsaturated carboxylic acid remains, resulting in the formation of bubbles in the resulting composite material. As a result of various studies on polypropylene that has adhesive properties that do not cause such defects, the present inventors have found that a polypropylene composition containing a specific amount of a copolymer of propylene and an unsaturated carboxylic acid anhydride is an ethylene-vinyl acetate copolymer. The present inventors have discovered that they have excellent adhesion to saponified materials, nylon, polyvinyl alcohol, polyolefins, etc., and have provided the present invention. The present invention is an alternating copolymer of α-olefin having 2 to 4 carbon atoms and an unsaturated carboxylic acid anhydride.
It is a polyolefin composition consisting of 10% by weight and 99.5 to 90% by weight of polyolefin. The copolymer used in the composition of the present invention is α-
An alternating copolymer containing alternating olefins and unsaturated carboxylic acid anhydrides is used. Such an alternating copolymer itself is known, for example, from "Experimental Methods of Polymer Synthesis", page 143 (published by Kagaku Dojin), but it is known that a composition of a specific proportion of an alternating copolymer and a polyolefin is - It was discovered for the first time by the present inventors that it has excellent adhesion to saponified vinyl acetate copolymers, polyvinyl alcohol, nylon, and even polyolefins. Such alternating copolymers contain from 2 carbon atoms to
The α-olefins of No. 4, i.e., ethylene, propylene, butylene, and the unsaturated carboxylic acid anhydride described below were mixed with dicumyl peroxide and dicumyl peroxide in the presence of a solvent.
It can be obtained by reaction using an organic peroxide such as benzoyl peroxide or azobisisobutyronitrile as a catalyst. The unsaturated carboxylic acid anhydride may be any compound that copolymerizes with the α-olefin in the presence of the catalyst. In general, it is a compound that has one polymerizable double bond and two carboxyl groups are dehydrated. It may also be a mixed carboxylic acid anhydride consisting of a monocarboxylic acid having a double bond and a monocarboxylic acid having no double bond. For example, cis-4-cyclohexene-1,2-dicarboxylic anhydride (commonly known as tetrahydrophthalic anhydride), endo-bicyclo[2.2.1]-5-heptene-2,3-dicarboxylic anhydride (commonly known as hymic anhydride), Endo-bicyclo [2.2.1]-1.2.3.4.7.7-hexachloro-2-
Heptene-5.6-dicarboxylic anhydride (commonly known as chlordic anhydride), maleic anhydride, itaconic anhydride, succinic anhydride, phthalic anhydride, pyromellitic anhydride, glutaric anhydride, thiodipropionic anhydride, acrylic acid - Examples include acetic anhydride. Among these, dicarboxylic acid anhydrides are preferred, and among these, maleic anhydride is most preferably used. Further, as the reaction solvent, a certain one is used in which the α-olefin and the unsaturated carboxylic acid anhydride are dissolved and the produced copolymer is insoluble, such as benzene, heptane, toluene, xylene, and the like. The reaction conditions vary somewhat depending on the type of organic peroxide catalyst, but generally the reaction temperature is 40 to 80°C, preferably 55 to 65°C, and the pressure is 2 to 20 Kg/cm ² , preferably 3 to 15 Kg/cm ² Under stirring, usually at 300 to 700 rpm, the copolymer is obtained in a yield of 50 to 80%. The alternating copolymer of α-olefin and unsaturated carboxylic acid anhydride obtained by the reaction is a powdered polymer, and the specific viscosity in dimethylformamide is generally about 0.2 at a concentration of 0.5 g/100 mol.
~0.6 range. The composition of the present invention contains 0.5 to 10% by weight of a copolymer consisting of α-olefin and unsaturated carboxylic acid anhydride.
and 99.5 to 90% by weight of polyolefin. As the polyolefin, polyolefins such as polyethylene, polypropylene, polybutene-1, etc. are used, and particularly preferably, a polymer made of the same α-olefin used in the copolymer is used. Polyolefins are not limited to homopolymers;
Used are ethylene-propylene copolymers copolymerized with other α-olefins, such as ethylene-propylene copolymers copolymerized with a small amount of ethylene, or polyolefin mixtures blended with other polyolefins. If the proportion of the copolymer in the polyolefin composition is less than 0.5% by weight, the adhesion to saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol or nylon will not be sufficient. And vice versa
If it exceeds 10% by weight, the adhesiveness with polyolefin will decrease and adhesive strength that can withstand practical use will not be obtained. In particular, when the proportion of the copolymer is in the range of 0.5 to 5% by weight, the adhesion to both saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, nylon and polyolefin is particularly excellent. Examples of the method for preparing the polyolefin composition of the present invention include mixing the copolymer and polyolefin pellets using a tumbler blender, Henschel mixer, etc., and then thoroughly kneading them using a Banbury mixer, extruder, etc. . The polyolefin composition of the present invention may contain a heat-resistant stabilizer, a weather-resistant stabilizer, a lubricant, an antistatic agent, a nucleating agent, a filler, a pigment, a flame retardant, an anti-blocking agent, etc. in the amounts commonly used. The polyolefin composition of the present invention has ethylene-
In order to exhibit good adhesion with saponified vinyl acetate copolymer, polyvinyl alcohol, nylon, polyolefin, etc., new multilayer laminates, such as saponified ethylene-vinyl acetate copolymer/polyolefin composition, polyvinyl alcohol/polyolefin, etc. Compositions, two-layer laminates such as nylon/polyolefin compositions, three-layer laminates such as saponified ethylene-vinyl acetate copolymer/polyolefin compositions/polyolefins, nylon/polyolefin compositions/polyolefins, and further three-layer laminates. A five-layer laminate, etc., in which another polymer layer is laminated to the product via a polyolefin composition, is provided. In the above multilayer laminate, it is preferable that the polyolefin used in the composition and the polyolefins in the other layers are of the same type. Examples include a saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, or a composition comprising a nylon/propylene-maleic anhydride copolymer and polypropylene/a three-layer laminate comprising polypropylene. The stretched film obtained from this three-layer laminate has excellent gas barrier properties, oil resistance, water impermeability, and high strength, so it is suitable as a food packaging material. In addition, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol or nylon/
A stretched film obtained from a five-layer laminate consisting of a composition consisting of a propylene-maleic anhydride copolymer and polypropylene/polypropylene/the aforementioned polypropylene composition/an ethylene-propylene random copolymer with an ethylene content of 0.3 to 3% by weight is It has excellent barrier properties, oil resistance, water impermeability, and heat sealability, making it suitable as a food packaging material. The saponified ethylene-vinyl acetate copolymer used in the present invention has an ethylene content of 20 to 60 mol%, preferably 25 to 50 mol%, and a saponification degree of 93% or more, preferably 96% or more. is used. Further, as the nylon, nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, etc. are used. In the present invention, lamination methods such as an in-die lamination method, an outside-die lamination method, and thermocompression bonding using a press are employed as a method for obtaining a multilayer laminate. In the multilayer laminate, each layer may be unstretched, uniaxially stretched, or biaxially stretched, or uniaxially or biaxially stretched after lamination. The present invention will be described below with reference to Examples, but the present invention is not limited thereto. In the Examples, adhesiveness was evaluated using peel strength. The saponified ethylene-vinyl acetate copolymer biaxially stretched film (30μ)/polyolefin composition sheet/polyolefin sheet were stacked in this order, and after press molding under a pressure of 70 kg/ ^cm2 for 3 minutes in a hydraulic press at 230°C, The two layers, the saponified ethylene-vinyl acetate copolymer and the polyolefin composition, which are in contact with the surface on which the adhesive peel strength is to be measured, are held in the chuck of an Autograph manufactured by Shimadzu Corporation, and the stress detected at a peeling speed of 20 mm/min is measured. was measured and defined as peel strength. Example 1 Benzene 1 was placed in an autoclave with an internal volume of 2, 467 g of maleic anhydride was dissolved therein, 250 ml of propylene monomer was injected, 1.26 g of azobisisobutyronitrile catalyst was added, and the mixture was stirred at a temperature of 60°C. Polymerization was carried out for 5 hours while stirring to obtain an alternating copolymer of propylene and maleic anhydride, which was washed with ether and then dried. The yield was 67%. The copolymer was a white powdery polymer with a specific viscosity of 0.45 in dimethylformamide at a concentration of 0.5 g/100 mol. The alternating copolymer obtained in this way was then mixed with isotactic polypropylene (MFI=10 g/10 min).
The mixture was kneaded in the proportions shown in Table 1 to obtain a polypropylene composition. When the peel strength of this composition was measured, the peel strength against a polypropylene sheet and a saponified ethylene-vinyl acetate copolymer was as shown in Table 1.

[Table] From the results in Table 1, it is clear that the composition of the present invention exhibits adhesive properties to both polypropylene and saponified ethylene-vinyl acetate copolymer. Example 2 A commercially available ethylene-maleic anhydride alternating copolymer (manufactured by Monsanto, USA, product number D4032) and polyethylene (Hizex 3000, manufactured by Mitsui Petrochemicals) were
Peel strength against saponified ethylene-vinyl acetate copolymer (same as in Example 1) and polyethylene (Hizex 3000 manufactured by Mitsui Petrochemicals) was measured in the same manner as in Example 1 using a composition with the blending ratio shown in the table. did. The results are also listed in Table 2.

【table】

[Table] Example 3 Put benzene 1 into an autoclave with an internal volume of 2, dissolve 480 g of maleic anhydride, then inject 200 ml of butene-1 monomer, and add 2 g of azobis, isobutyl nitrile (AIBN) catalyst.
Polymerization was carried out at a temperature of 60°C for 4 hours while stirring with a stirrer to obtain an alternating copolymer of butene-1 and maleic anhydride. The polymer was then washed with ether and dried to obtain 200 g of a white powdery polymer, which had a specific viscosity of 1.4 in dimethylformamide at a concentration of 0.5 g/100 mol. The alternating copolymer was kneaded with polybutene-1 ("WITRON 0100" manufactured by Adeka Argus Chemical Co., Ltd., MFI=0.4) at the blending ratio shown in Table 3 to obtain a composition. This composition was used in the same manner as in Example 1 to obtain saponified ethylene-vinyl acetate copolymer (same as in Example 1) and polybutene-1 (manufactured by Adeka Argus Chemical Co., Ltd.).
The peel strength against “WITRON 1210A” (MFI=2.0) was measured. The results are also listed in Table 3.

【table】

[Table] Example 4 Put 1 part of benzene into an autoclave with an internal volume of 2, dissolve 582 g of phthalic anhydride, then inject 250 ml of propylene monomer, add 2 g of azobisisobutyronitrile catalyst, and heat at 60°C. Polymerization was carried out for 5 hours while stirring to obtain an alternating copolymer of propylene and phthalic anhydride. When this product was washed with ether and dried, the yield was 40%.
The alternating copolymer is a white powdery polymer with a specific viscosity of 0.5 g/100 mol in dimethylformamide.
It was 0.45 under the concentration of The alternating copolymer thus obtained was made of isotactic polypropylene (MFI = 10 g/10 min) at 100%
When the peel strength of a polypropylene composition mixed at 10% by weight was measured, it was 1500g/10mm for both a polypropylene sheet and a saponified ethylene-vinyl acetate copolymer film.
It was more than the width. Application example 1 Isotactic polypropylene (MFI=
2.0g/10 minutes) was obtained using an extruder with a T-die set at 290°C to obtain a sheet with a thickness of 1.5mm, and then this sheet was longitudinally stretched using a roll-type stretching machine set at a roll surface temperature of 155°C. A uniaxially stretched sheet with a thickness of 0.3 mm was produced by stretching 5 times in the direction. This sheet is air temperature
The film was stretched 10 times in the axial direction using an oven-type stretching machine set at 155° C. to obtain a biaxially stretched polypropylene film with a thickness of 30 μm. Next, the polypropylene composition No. 8 of Example 1 and the saponified ethylene-vinyl acetate copolymer were each put into a coextrusion laminator set at 250°C, and the thickness of the polypropylene composition was placed on the biaxially stretched polypropylene film. Thickness of saponified ethylene-vinyl acetate copolymer: 10μ
Extrusion lamination was performed to obtain a three-layer laminate film of biaxially oriented polypropylene/polypropylene composition/saponified ethylene-vinyl acetate copolymer. The oxygen permeability of this laminated film is 8
At cc/ ^m2・24hr・atm, the haze was 2.8%. Application example 2 Biaxially oriented polypropylene used in application example 1/
Polypropylene composition/Ethylene in three-layer laminated film of saponified ethylene-vinyl acetate copolymer
No. 1 from Example 1 was added to the saponified vinyl acetate copolymer side.
Polypropylene composition of 8 15μ and MFI=8.0
g/10 minutes, 20μ of propylene-ethylene random copolymer with an ethylene content of 2.5% by weight was coextruded and laminated so that the polypropylene composition was on the side of the saponified ethylene-vinyl acetate copolymer to form a biaxially oriented polypropylene/polypropylene composition. A five-layer laminate film was obtained, which consisted of a product/saponified ethylene-vinyl acetate copolymer/polypropylene composition/propylene-ethylene random copolymer. This film had an oxygen permeability of 7 c.c./m ² 24 hr atm, a heat sealing temperature of 135° C., and a haze of 3.0%. Comparative Example In No. 8 of Example 1, a graft copolymer copolymerized with maleic anhydride at a proportion of 7% by weight was used instead of the alternating copolymer, and the proportion of maleic anhydride in the composition was A polyolefin composition was obtained in the same manner except that the composition was the same. Using the obtained polyolefin composition, the peel strength with polypropylene and the saponified ethylene-vinyl acetate copolymer were measured in the same manner as in Example 1, and the results were 1300 g/10 mm width and 450 g/10 mm width, respectively. It was hot.

Claims (1)

[Scope of Claims] 1. A polyolefin composition comprising 0.5 to 10% by weight of an alternating copolymer of an α-olefin having 2 to 4 carbon atoms and an unsaturated carboxylic acid anhydride and 99.5 to 90% by weight of a polyolefin. 2. The composition according to claim 1, wherein the α-olefin is propylene. 3. The composition according to claim 1, wherein the unsaturated carboxylic anhydride is maleic anhydride. 4. The composition according to claim 1, wherein the proportion of the alternating copolymer is 0.5 to 5% by weight. 5 α where polyolefin constitutes an alternating copolymer
- The composition according to claim 1, which is a polymer of α-olefin, which is the same as olefin. 6. The composition according to claim 1, wherein the polyolefin is polypropylene.