JPH06306198A - Olefin resin molding having gas-barrier properties - Google Patents

Abstract

PURPOSE:To obtain the molding being improved in adhesion to the constituent thin film and gas-barrier properties by forming a thin film of an inorganic oxide on the surface of a molding of a specified modified polyolefin. CONSTITUTION:A modified polyolefin of an MFR (JIS K 7210) of 0.01-100g/10min, obtained by grafting 0.01-10wt.% alpha,beta-ethylenically unsaturated carboxylic acid onto a polyolefin, is molded to obtain a molding of a thickness of 200mum-10mm. A thin film of an inorganic oxide of a thickness of 200-4000Angstrom is vapor-deposited on the surface of this molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product for packaging which is used for protecting foods, electronic parts and the like and has an excellent gas barrier property.

[0002]

2. Description of the Related Art Foods, electronic industrial parts, etc. are used as films and containers.
The contents of the
It has been proposed to prevent deterioration and maintain quality for a long time.
For example, in Japanese Patent Publication No. 53-12953, the thickness is 5
~ 300μm polyethylene terephthalate, cellophane
Frame, nylon, polypropylene, polyethylene, etc.
On at least one side of a kisible plastic film,
General formula Si_xO _y(X = 1 or 2, y = 0, 1, 2 or
Or 3) the thickness of the silicon oxide having a composition of 100 to 3000
High degree of air resistance with a transparent thin film layer of Angstrom
And a transparent flexible plastic film with moisture resistance
Rum 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 a container, further when external sterilization or heat is 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 polyolefin obtained by modifying an polyolefin by grafting an α, β-ethylenically unsaturated carboxylic acid, wherein the concentration of the constituent unit based on the unsaturated carboxylic acid in the modified polyolefin is 0.
Provided is an olefin-based resin molded product having a gas barrier property, in which an inorganic oxide thin film is formed on the surface of a modified polyolefin molded product in an amount of 01 to 10% by weight.

[0007]

In the present invention, since the modified polyolefin of the substrate has a carboxyl group (-COOH), the adhesiveness with the inorganic oxide vapor deposition film becomes strong.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Modified polyolefin films, modified polyolefins molded into containers,
It is obtained by graft-polymerizing α, β-ethylenically unsaturated carboxylic acid (including its anhydride) on polyolefin. As a method of graft polymerization, a method of melt-kneading a polyolefin, α, β-ethylenically unsaturated carboxylic acid, and a catalyst in an extruder (Japanese Patent Publication No. 43-274).
No. 21, JP-B-59-15127), or a method in which an unsaturated carboxylic acid for grafting and a catalyst are added to a polyolefin dissolved in a suitable solvent and the mixture is heated and stirred (JP-B-44-15422, JP-B-44152). 52-30546) and the like.

Examples of the polyolefin to be modified include homopolymers of α-olefins having 2 to 8 carbon atoms such as ethylene, propylene, butene-1, and pentene-1, as well as copolymers of ethylene with other α-olefins. Α-of polymers such as ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer and propylene-butene-1, propylene-ethylene-butene-1 copolymer Also included are crystalline polymers of olefins. You may blend and use these polymers and copolymers.

As the unsaturated carboxylic acid to be grafted, acrylic acid, maleic acid, fumaric acid, itaconic acid,
Hymic acids or their anhydrides may be mentioned. Of these, acrylic acid or maleic anhydride is preferable. The modified polyolefin may be diluted with an unmodified polyolefin before use. When 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 even if it exceeds the above range, the binding force is improved. In addition, since the decomposition reaction occurs in the polypropylene type during the grafting reaction and the crosslinking reaction occurs in equilibrium in the polyethylene type during the grafting reaction, the low molecular weight component in the polypropylene type increases and the binding force decreases, and the gel type in the polyethylene type decreases. There are problems such that many stretched films cannot be produced.

MFR of modified polyolefin or modified polyolefin diluted with unmodified polyolefin
(JIS K-7210) is sufficient as long as a molded product can be obtained, and is preferably 0.1 to 100 g / 10 minutes, more preferably 0.5 to 20 g / 10 minutes.

Molded Article A molded article is formed into a film, sheet, container, box or the like by extrusion molding, injection molding, vacuum molding, hollow 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. Further, the film or sheet may be 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.

[0014]Inorganic oxide deposition As a thin film of inorganic oxide, SiO_x, SnO_x, Zn
O_x, IrO_x200-4,000 ang straws
Preferably 300-3,000 Angstroms
Things are used. Evaporated film thickness 200-4,000
Ngstrom has transparency, deposition rate, gas barrier
However, it is restricted by the film properties, film winding properties, and the like. Evaporation method
Then, the molded product is vacuumed in the high frequency induction heating type vapor deposition machine.
Bottom (1 x 10 ^-3~ 1 x 10⁶Steam the inorganic oxide with
How to wear (Japanese Patent Publication No. 53-12963); Exhaust in advance
Then, the organic silicon compound volatilized in the vacuumed evaporator.
Magnetron for gas flow containing gas, oxygen and inert gas
Plasma is generated by low discharge to generate SiO_xThe steam
A method of vapor depositing a molded article in a machine (Japanese Patent Laid-Open No. 64-877).
72, USP 4,557,946, USP 4,59
9, 678) and the like. Also published in November 1990
Industrial Materials, Vol. 38, No. 14, pp. 104-105
With ion plating method, high frequency plasma CVD
Method, electron beam (EB) vapor deposition method, sputtering method
The principle is 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.

[0016] Production 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 then the concentration of the constituent 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, 0.8 parts by weight of benzoyl peroxide and 1.2 parts by weight of maleic anhydride were added, and the modified copolymer was added in the same manner 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.

[0018] Production of modified polyethylene Example 3 linear low-density polyethylene (MFR 2 g / 10 min, density 0.920 g / cm ^3, ethylene content is 91.0 wt%, hexene containing 9.0 wt%) 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 and reprecipitated with a large amount of acetone, and then the concentration of the structural 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 ) SiO ₂ vapor-deposited biaxial in the same manner as in Example 1 except that the diluted polypropylene (concentration of maleic acid in the diluted product: 0.35 wt%) diluted with 95 parts by weight is used instead of the modified polypropylene. 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 Unmodified polypropylene (MFR 0.8 g / 10 min, dense polypropylene)
Degree 0.905g / cm³) For modified polypropylene
SiO 2 is used in the same manner as in Example 1 except that it is used instead. ₂Vapor deposition
An axially oriented polypropylene film was produced.

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 diluted (constituent unit concentration of maleic acid 0.07% by weight) was used instead of the modified polypropylene, and SiO ₂ was used in the same manner as in Example 1.
A vapor-deposited biaxially oriented polypropylene film was produced.

Example 4 The modified polyethylene obtained in Example 3 was melted by an extruder and extruded into a cylindrical shape from an inflation die at 160 ° C., air was blown into the bubbles to expand them to a blow ratio of 2, and then the corona was used. 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 3 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, the same procedure as in Example 4 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 4 and Comparative Examples 1 to 3 were used in a gel votester manufactured by each instrumental analyzer,
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) secondary processing varies Examples 1-2 against, and the SiO ₂ deposition surface of the SiO ₂ deposited film obtained in Comparative Examples 1-2, 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]

[0029]

EFFECTS OF THE INVENTION A molded article of a crystalline olefin copolymer having a carboxyl group, on which the inorganic oxide of the present invention is vapor deposited, is
It is a resin molded product whose gas barrier properties do not deteriorate even when heat or force is applied during secondary processing or 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 Petrochemical Co., Ltd. Yokkaichi Research Institute

Claims (1)

[Claims] 1. A modified polyolefin obtained by graft-modifying a polyolefin α, β-ethylenically unsaturated carboxylic acid, wherein the concentration of the constituent unit based on the unsaturated carboxylic acid in the modified polyolefin is 0.01 to 10% by weight. An olefin resin molded product having a gas barrier property, in which an inorganic oxide thin film is formed on the surface of the modified polyolefin molded product.