JP3430551B2 - Olefin resin molded product with gas barrier properties - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin resin molded article having excellent gas barrier properties, which is used for protecting foods, electronic parts and the like.

[0002]

2. Description of the Related Art It has been proposed to wrap foods, electronic parts, etc. in a film or a container to prevent the permeation of oxygen to prevent the contents from being oxidized and to maintain the quality for a long time.
For example, in Japanese Patent Publication No. 53-12953, the thickness is 5
-300 μm polyethylene terephthalate, cellophane, nylon, polypropylene, polyethylene or other flexible plastic film on at least one side,
Thickness of silicon oxide having a composition represented by the general formula: Si _x O _y (x = 1 or 2, y = 0, 1, 2, or 3) 100 to 3000
A transparent flexible plastic film having a high degree of air permeability and moisture resistance provided with an angstrom transparent thin film layer is disclosed.

Further, Japanese Patent Laid-Open No. 63-237940 discloses a metal oxide of one kind of metal selected from the group consisting of In, Sn, Zn, Zr and Ti on at least one surface of the flexible plastic film. Is disclosed by sputtering, and a transparent heat-sealable resin film is coated on the transparent gas barrier film.

When the film material is a resin having a polar group such as polyethylene terephthalate, nylon or cellophane, the film and the inorganic oxide film have sufficient adhesion and a good gas barrier property. However, even if a vapor-deposited thin film made of the above inorganic oxide is formed on the surface of a polyolefin molded product having no polar groups such as polypropylene and polyethylene, the adhesion between the polyolefin molded product and the thin film is weak. When laminating a heat-sealable resin having a melting point lower than that of the polyolefin constituting the molded article in order to impart heat-sealing property to the vapor-deposited product, or by using this laminated product, it can be used for bag making or lid sealing. When performing the next processing, using these bags, filling the contents in the container, further when external sterilization and heat are applied to the molded product during retort sterilization, the inorganic oxide thin film peels from the polyolefin molded product, There is a problem that the gas barrier property is lowered and it cannot be put to practical use.

[0005]

DISCLOSURE OF THE INVENTION The present invention has a gas barrier property even when an olefin resin molded article having an inorganic oxide thin film deposited thereon is not peeled off during secondary processing or during use. It is an object of the present invention to provide a resin molded product that does not deteriorate.

[0006]

The present invention is a modified polypropylene graft-modified with an α, β-ethylenically unsaturated carboxylic acid, wherein the structural unit based on the α, β-ethylenically unsaturated carboxylic acid in the modified polypropylene. The concentration is 0.01
Provided is an olefin-based resin molded product having a gas barrier property, which is formed by depositing an inorganic oxide thin film on the surface of a modified polypropylene molded product of 10% by weight.

[0007]

In the present invention, as the modified polyolefin of the substrate, the modified polypropylene having a specific amount of carboxyl group (-COOH) is used, so that the adhesion to the inorganic oxide vapor deposition film becomes strong.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Modified Polyolefin In the present invention, the modified polyolefin of the substrate is obtained by graft-polymerizing α, β-ethylenically unsaturated carboxylic acid (including its anhydride) on polypropylene.
As the method of graft polymerization, polypropylene,
A method of melt-kneading an α, β-ethylenically unsaturated carboxylic acid and a catalyst in an extruder (Japanese Examined Patent Publication No. 43-27421, Japanese Examined Patent Publication No. 59-15127) or grafting on polypropylene dissolved in a suitable solvent. A method for adding α, β-ethylenically unsaturated carboxylic acid and a catalyst for heating and stirring (Japanese Patent Publication No. 44-15422 and Japanese Patent Publication No. 52-305).
46) etc.

As the polypropylene to be modified, in addition to a propylene homopolymer, a copolymer of propylene and ethylene or other α-olefin, for example, an ethylene-propylene copolymer, propylene-butene-1, propylene-ethylene- Also included are crystalline polymers of α-olefins such as butene-1 copolymer. You may blend and use these polymers and copolymers. Further, the modified polyolefin may be diluted with an unmodified polyolefin before use. MFR of modified polypropylene or modified polypropylene diluted with unmodified polyolefin (JIS
K-7210) has only to be a molded product, and is usually 0.1 to 100 g / 10 minutes, preferably 0.5 to 20 g.
/ 10 minutes.

Further, if the concentration of the constituent unit based on α, β-ethylenically unsaturated carboxylic acid in the molded product is less than the above range, the binding force with the inorganic oxide thin film is insufficient, and if it is more than the above range. However, there is no improvement in the binding force, and since a decomposition reaction occurs during the grafting reaction, there arises a problem that the low molecular weight component increases and the binding force decreases.

On the other hand, examples of the α, β-ethylenically unsaturated carboxylic acid to be grafted on polypropylene include acrylic acid, maleic acid, fumaric acid, itaconic acid, hymic acid and their anhydrides. Among them, acrylic acid is preferable. , Maleic anhydride, especially maleic anhydride is preferred.

Molded Article The molded article is formed into a film, sheet, container, box or the like by extrusion molding, injection molding, vacuum molding, blow molding or the like. or,
Modified polyolefin and polyethylene, polypropylene,
It may have a laminate structure with a thermoplastic resin such as an ethylene / vinyl acetate copolymer, polyamide, polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide, polyphenylene ether, or polycarbonate. The film or sheet is preferably stretched.

The thickness of the film is 5 to 200 μm,
200 to 1,500 μm for sheets, 300 to 2,500 μm for small containers, box-shaped housings, etc., 1 to 10 m for tank containers and 20 liter chemical containers.
m is common. If necessary, the molded product may be subjected to corona discharge treatment, ozone treatment, glow discharge treatment, plasma treatment, or oxidation treatment with a chemical agent on the surface of the modified polyolefin. However, in general, a thin film of an inorganic oxide is often vapor-deposited together with these oxidation treatments, and thus it is not necessary to perform the oxidation treatment during or after the molding.

Vapor Deposition of Inorganic Oxide As a thin film of inorganic oxide, SiO _x , SnO _x , Zn
O _x, usually 200 to 4,000 Å, such as IrO _x, it is preferably utilized as a 300 to 3,000 angstroms. The thickness of this deposited film is
It is restricted by vapor deposition rate, gas barrier property, film winding property, and the like. As the vapor deposition method, a method of depositing an inorganic oxide on a molded article under vacuum (1 × 10 ⁻³ to 1 × 10 ⁶ torr) in a high frequency induction heating type vapor deposition machine (Japanese Patent Publication No. 53-12).
963); a gas flow containing an organosilicon compound, oxygen, and an inert gas which has been evacuated and evacuated in advance in a vapor deposition machine is used to generate plasma by magnetron glow discharge to deposit SiO _x on a molded article in the vapor deposition machine. Method (JP-A-64-87772, USP 4,557,94)
No. 6, USP 4,599,678) and the like. Again 1
Industrial materials published in November 990, Volume 38, No. 14, pp. 104 to 105, are classified as ion plating method, high frequency plasma CVD method, electron beam (EB) vapor deposition method, and sputtering method, and the principle thereof. Has been introduced.

[0015]

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not particularly limited thereby.

Production Example of Modified Polypropylene Example 1 Polypropylene (MFR 2 g / 10 min, density 0.9
(05 g / cm ³ ) powder (100 parts by weight), benzoyl peroxide (0.8 parts by weight) and maleic anhydride (1.2 parts by weight) were added, and the mixture was mixed with a Henschel mixer. The mixture was extruded into a shape, cooled with water, and then cut to obtain pellets. The modified polypropylene pellets were dissolved in boiling xylene, reprecipitated with a large amount of acetone, and the concentration of the structural unit based on maleic anhydride in the modified polypropylene was measured by infrared absorption spectroscopy. Graft copolymerization was carried out in an amount of 0.7% by weight.

Example 2 Ethylene-propylene copolymer (ethylene content 5%, M
FR 1 g / 10 min, density 0.89 g / cm ³ ) 100 parts by weight of powder to which 0.8 parts by weight of benzoyl peroxide and 1.2 parts by weight of maleic anhydride were added, and modified copolyester as in Example 1 A coalesce was manufactured. The concentration of the maleic anhydride component in the modified copolymer was measured and found to be 0.9% by weight.

Production Example of Modified Polyethylene Example 3 Linear low-density polyethylene (MFR 2 g / 10 min, density 0.920 g / cm ³ , ethylene content 91.0% by weight, hexene content 9.0% by weight) 100 2,5-dimel-2,5-di (t-butylperoxy) in parts by weight
Hexane (0.04 parts by weight) and maleic anhydride (2 parts by weight) were added, mixed with a Henschel mixer, extruded into a strand at 180 ° C. from a die with an extruder, cooled with water, and cut to obtain pellets. The modified polypropylene pellets were dissolved in boiling xylene, reprecipitated with a large amount of acetone, and the concentration of the constituent unit based on maleic anhydride in the modified polyethylene was measured by infrared absorption spectroscopy. Graft copolymerization was performed in an amount of 0.9% by weight.

Example 1 The modified polypropylene obtained in Example 1 was melted in an extruder to obtain T-
A sheet having a thickness of 1 mm was obtained by extruding a sheet at 238 ° C. from a die and cooling with a metal roll. This sheet 12
Heat to 0 ° C, and use the difference in peripheral speed of the rolls to move vertically 5
It was stretched twice. Then, lead it into the tenter oven, 15
After reheating to 7 ° C., it was stretched 10 times in the transverse direction using a tenter, annealed at 163 ° C., and corona discharge treated to obtain a biaxially stretched film having a thickness of 20 μm.

This biaxially stretched film subjected to corona discharge treatment was placed in a plasma deposition apparatus, and the inside of the apparatus was set at 1 × 10 ^-6.
After reducing the pressure under a reduced pressure of torr, a mixed gas of 3 parts by volume of hexamethyldisiloxane, 3 parts by volume of oxygen, 20 parts by volume of helium, and 13 parts by volume of argon was introduced, and glow discharge was performed from the unbalanced magnetron to generate plasma. A thin film of SiO ₂ was deposited in the form of a biaxially stretched film. The glow discharge conditions during vapor deposition were such that the obtained SiO ₂ vapor-deposited biaxially stretched film had an oxygen permeability of 5.0 cc / m ² · atm · day.
(JIS 1707-35).

Example 2 5 parts by weight of the modified polypropylene obtained in Example 1 was added to unmodified polypropylene (MFR 0.8 g / 10 min, density 0.95).
0 g / cm ³ ) diluted with 95 parts by weight (concentration of maleic acid constituent in the diluted product: 0.035% by weight) is used instead of the modified polypropylene in the same manner as in Example 1 for biaxial deposition of SiO _2. A stretched polypropylene film was produced.

Example 3 The modified copolymer obtained in Example 2 and the unmodified polypropylene used in Example 2 were melted by different extruders and fed to one die, which was layered in the die. Then, a sheet having a thickness of the modified copolymer layer of 0.1 mm, an unmodified polypropylene layer of 0.9 mm, and a total thickness of 1 mm was extruded to form a sheet and stretched in the same manner as in Example 1. A 20 μm film was prepared, the modified copolymer side was subjected to corona discharge treatment, and then a SiO ₂ vapor-deposited biaxially stretched film was produced in the same manner as in Example 1.

Comparative Example 1 A SiO ₂ vapor-deposited biaxially oriented polypropylene film was prepared in the same manner as in Example 1 except that unmodified polypropylene (MFR 0.8 g / 10 min, density 0.905 g / cm ³ ) was used instead of the modified polypropylene. Was manufactured.

Comparative Example 2 1 part by weight of the modified polypropylene obtained in Example 1 was added to unmodified polypropylene (MFR 0.8 g / 10 min, density 0.90).
5 g / cm ³ ) 99 parts by weight (maleic acid constituent unit concentration 0.007% by weight) diluted with SiO 2 in the same manner as in Example 1 except that the modified polypropylene was used.
_Two vapor-deposited biaxially oriented polypropylene films were produced.

Comparative Example 3 The modified polyethylene obtained in Example 3 was melted by an extruder and extruded into a cylindrical shape at 160 ° C. from an inflation die, and air was blown into the bubble to expand it to a blow ratio of 2 and then the corona. Electric discharge treatment was performed to obtain a modified polyethylene film having a thickness of 40 μm. Using this film, a SiO ₂ vapor-deposited polyethylene film was produced in the same manner as in Example 1.

Comparative Example 4 Unmodified linear low density polyethylene (MFR 2 g / 10
Min, except for using a density 0.920 g / cm ³⁾ in place of the modified polyethylene is in the same manner as in Comparative Example 3 SiO ₂
A vapor-deposited polyethylene film was produced. The oxygen permeability of all stretched films was 5.0 cc / m ² · atm ·
The glow discharge conditions were changed so as to obtain the day.

Evaluation (1) Change with respect to external stress The SiO ₂ vapor-deposited films obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were used in a gel votester manufactured by Rikiki Co., Ltd.
After rolling the film into a tube shape, both ends of the tube were fixed to a gripping device of a tester, and a twist of ± 90 ° was repeated 10 times, and then the oxygen transmission rate was measured. The measured values are shown in Table 1. (2) the SiO ₂ deposition surface of the SiO ₂ deposited film obtained by the change Examples 1-3, and Comparative Examples 1 to 4 for the secondary processing, using a laminator apparatus,
Melt index 5g / 10min, density 0.922g /
cm ³ of low density polyethylene was extruded from a T-die at 320 ° C. into a film having a thickness of 20 μm and laminated. The oxygen transmission rate of this laminate is shown in Table 1.

[0028]

[Table 1] Unit: cc / m ² · atm · day

[0029]

EFFECT OF THE INVENTION The olefin resin molded article on which the inorganic oxide of the present invention is vapor deposited is a resin molded article whose gas barrier property does not deteriorate even when heat or force is applied during secondary processing or during use. Therefore, it is also useful as a retort pouch packaging material and an IC packaging material.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Mizuno 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Yuka Co., Ltd. inside the Yokkaichi Research Institute (56) Reference JP-A-58-110242 (JP, A) JP-A 3-244535 (JP, A) JP 5-131590 (JP, A) JP 6-190961 (JP, A) JP 5-287103 (JP, A) JP 6-298263 (JP, A) JP 55-155035 (JP, A) JP 60-137940 (JP, A) JP 5-51420 (JP, A) JP 4-7139 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) C08J ⁷ /04-7/06 C08L 23/00-23/36

Claims (5)

(57) [Claims] 1. A modified polypropylene graft-modified with an α, β-ethylenically unsaturated carboxylic acid, wherein the concentration of the constituent unit based on the α, β-ethylenically unsaturated carboxylic acid in the modified polypropylene is 0.01 to. An olefin resin molded product having a gas barrier property, which is formed by depositing an inorganic oxide thin film on the surface of a modified polypropylene molded product of 10% by weight. 2. The olefin resin molded article having gas barrier properties according to claim 1, wherein the α, β-ethylenically unsaturated carboxylic acid is maleic anhydride. 3. The inorganic oxide thin film has a thickness of 200 to 4,0.
The olefin-based resin molded article having a gas barrier property according to claim 1 or 2, which is 00 angstrom. 4. The olefin resin composition having a gas barrier property according to claim 1, wherein the inorganic oxide thin film is made of SiOx. 5. The gas barrier property according to claim 1, wherein the molded product is a stretched sheet or film made of modified polypropylene, and an inorganic oxide thin film is formed on the surface of the sheet or the film. The given olefin resin molded product.