JP2002200710A - Gas barrier plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic material wherein minute defects such as pinholes, craze, cracks, free volume, void and air bubbles on the gas barrier surface layer (surface layer having a small gas permeability) formed by depositing, coating or co-extruding on the plastic surface can be repaired by a laser irradiation, and of which the gas barrier property is excellent. SOLUTION: A front surface layer is provided on the internal surface or the external surface or the internal and external surfaces of a plastic film or sheet. Then, the gas barrier property is increased by performing a laser irradiation on at least one surface of the front surface layer for this plastic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a plastic material having excellent gas barrier properties. More specifically, the present invention relates to a gas barrier plastic material obtained by irradiating a laser to at least one surface of a plastic inner surface or an outer surface or a surface layer provided on the inner and outer surfaces, and a packaging material capable of storing foods, pharmaceuticals, precision electronic components, and the like for a long time, It can be used for a transparent plastic plate or the like, which has a very low gas permeability such as water vapor and oxygen as a substitute for, and can be used for a liquid crystal display panel.

[Prior art]

Conventionally, gas barrier films, sheets, and gas barrier packages manufactured by coating or co-extrusion of vinylidene chloride (PVDC) are generally used. However, when waste incineration is performed, toxic gases such as dioxin are generated. Therefore, it is desired to develop films, sheets, and packaging bodies such as gas barrier containers, bottles, caps, closures, film packaging bags, paper packaging bags, paper cartons, and lid materials that do not use PVDC. ing.

[0003] Metal deposition, metal oxide deposition, hydrogenated carbon (diamond-like carbon, DL
C, also referred to as a-hC) evaporation, coating of inorganic inorganic compounds such as montmorillonite and vermiculite, coating of silicon oxide sol-gel, coating of water glass, evaporation of organic materials such as melamine and methylol melamine or Coating, PV
Coated plastics such as OH (polyvinyl alcohol) and EVOH (ethylene vinyl alcohol copolymer) have gas barrier properties, and are environmentally friendly materials that do not generate dioxin even after incineration. Has small defects such as pinholes (small holes), crazes (small cracks), cracks (cracks connected with crazes), free volume (space between polymers), cavities, bubbles, etc. When the liquid crystal display panel is used as a package, the quality of the packaged food or medicine deteriorates due to oxidative deterioration or aerobic bacteria multiply.

[Problems to be solved by the invention]

[0004] Micro defects such as pinholes, crazes, cracks, free volumes, cavities, bubbles, etc. of a gas barrier surface layer (a surface layer having low gas permeability) formed by vapor deposition, coating, and co-extrusion on a plastic surface according to a conventional technique. By repairing, a plastic material having even better gas barrier properties can be obtained.

[Means for Solving the Problems]

[0005] The present invention relates to a method of manufacturing a plastic, wherein at least one surface layer is provided on an inner surface or an outer surface or an inner or outer surface of a plastic.
The conventional problem was solved by irradiating a laser to repair small defects such as pinholes, crazes, cracks, free volumes, cavities, and bubbles in the surface layer and to improve gas barrier properties.

Small defects such as pinholes, crazes, cracks, free volumes, cavities, bubbles, etc. in a surface layer provided on a plastic surface by a method such as vapor deposition, coating, and coextrusion can be repaired by irradiating a laser. Was revealed. As a laser, a single wavelength laser such as an excimer laser shows an excellent effect,
Although pulse irradiation of an excimer laser having a wavelength of 248 nm and an energy of 5 mj / cm ² or more has been effective, the laser used in the present invention is not limited to this range.

When a surface layer provided on the surface of a plastic is irradiated with a laser, the temperature of the irradiated part rapidly rises. When a laser is applied to a small defect such as a pinhole, craze, crack, free volume, cavity, or bubble, the temperature of the small defect such as a pinhole, craze, crack, free volume, cavity, or bubble in the irradiated surface layer is irradiated. Rapidly rises, melting, reaction, and homogenization occur. When laser irradiation is interrupted, cooling and solidification occur instantaneously.

When the laser irradiation is interrupted, the surface layer is melted, reacted, and homogenized. When the laser irradiation is interrupted, the surface layer is instantaneously cooled and solidified as it is, and becomes a pinhole or craze through which water vapor or gas passes. The number of micro defects such as cracks, free volumes, cavities, bubbles, etc. is dramatically reduced, and the gas barrier property is improved.

[0009] The film and sheet having improved water vapor barrier property and gas barrier property obtained by irradiating a laser to a surface layer provided on the inner surface, outer surface, or inner and outer surfaces of the plastic film or sheet manufactured by the above method is a liquid crystal display. It can be used as a substitute for glass that prevents water vapor and gas permeation such as plates. Containers, bottles, cups, trays, caps, closures, bags, bags, pouches, containers with improved water vapor barrier properties and gas barrier properties by performing laser irradiation on the surface layer provided on the inner or outer or inner and outer surfaces of the carton, Bottles, cups,
Can manufacture trays, caps, closures, bags, bags, pouches, cartons. A film packaging bag or film manufactured by irradiating a laser to the surface layer provided on the inner surface or the outer surface or the inner or outer surface of the plastic film or sheet, and laminating one or more films and sheets having improved water vapor and gas barrier properties. When packaging foods, beverages, and pharmaceuticals in high barrier packaging such as lids, paper packaging bags, paper cartons, paper trays, paper cups, and lids, the packaged contents do not absorb moisture or oxidize for a long period of time. Since the growth of aerobic bacteria is prevented and carbon dioxide gas does not escape, high quality immediately after production can be maintained for a long time.

[0010]

EXAMPLE 1 Oxygen permeability 145cc ^/ m 2 · 24hrs
A commercially available water glass (aqueous solution containing silicon oxide as a main component) was coated to a dry thickness of 2 μm on the 12 μm-thick biaxially stretched PET film. The coating film is referred to as a xerogel, a large coating pinholes, oxygen transmission rate after coating was 65cc ^/ m 2 · 24hrs. The xerogel film containing silicon oxide as a main component formed on the PET film was subjected to pulse irradiation with an excimer laser having a wavelength of 248 nm. The oxygen permeability of the PET film after excimer laser pulse irradiation is 19 cc / m
Was reduced to ² · 24hrs.

[0011]

Example 2 Oxygen permeability 145cc ^/ m 2 · 24hrs
Using a 12 μm thick biaxially stretched PET film, a mixed gas of acetylene and argon was blown in a vacuum to irradiate a 2.54 GHz microwave to deposit a hydrogenated carbon film to a thickness of 1000 °. Oxygen permeability was reduced to 12cc ^/ m 2 · 24hrs. Oxygen permeability Doing pulse irradiation of an excimer laser with a wavelength of 248nm in the hydrogenated carbon film was decreased to ^6cc / m 2 · 24hrs.

[0012]

EXAMPLE 3 Oxygen permeability 10cc ^/ m 2 · 24hrs,
Using a 600 μm thick APET (amorphous PET) sheet, hexamethyldisiloxane (HM
DSO) and a gas mixture of helium and oxygen 1
Irradiation of high frequency of 3.5 MHz, silicon oxide (Si
O ₂ ) film was deposited to a thickness of 750 °. Oxygen permeability was reduced to 0.5cc ^/ m 2 · 24hrs. A obtained
Wavelength 2 is applied to the SiO ₂ deposition surface of the PET / SiO ₂ deposition sheet.
Oxygen permeability Doing pulse irradiation of an excimer laser of 48nm was reduced to 0.2cc ^/ m 2 · 24hrs.

[0013]

Example 4 Oxygen permeability 10cc ^/ m 2 · 24hrs,
Using an APET (amorphous PET) sheet having a thickness of 600 μm, a mixed gas obtained by heating and evaporating silicon oxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ) in vacuum was deposited to a thickness of 800 °. Oxygen permeability is 0.3cc /
It was reduced to m ² · 24hrs. APET / Si obtained
SiO ₂ / Al ₂ O _{3 of} O ₂ / Al ₂ O ₃ co-deposited sheet
Oxygen permeability Doing pulse irradiation of an excimer laser with a wavelength of 248nm to the deposition surface is 0.1cc ^/ m 2 · 24hrs
Has dropped.

[0014]

EXAMPLE 5 Oxygen permeability 145cc ^/ m 2 · 24hrs
PVOH on a 12μ thick biaxially stretched PET film
(Polyvinyl alcohol) and PAA (polyacrylic acid)
And PAA-Na (sodium polyacrylate) mixed aqueous solution was coated to a dry thickness of 2 μm. Oxygen transmission rate after coating was 10cc / m 2 ^· 24hrs, but the coating film was swollen in a poor coating very water-resistant water. PV formed on PET film
248nm wavelength on OH, PAA and PAA-Na mixed film
When excimer laser pulse irradiation is performed, the oxygen permeability is reduced to 1 cc / m ² · 24 hrs, and PVOH
A cross-linking reaction of PAA and PAA occurred, resulting in a film having improved water resistance and not swelling in water. The obtained PET film is printed in six colors, dry-laminated with a 20 μ thick CPP (cast polypropylene film) and a polyurethane adhesive, heat-sealed to produce a bag, filled with nitrogen gas, and hermetically sealed with potato chips. Packaging was performed, but the taste after 6 months at room temperature was good.

[0015]

EXAMPLE 6 Oxygen permeability 145cc ^/ m 2 · 24hrs
12μ thick biaxially stretched PET film with TMSO
Hydrochloric acid is added to (tetramethoxysilane) for hydrolysis, sol-gel coating of a mixed aqueous solution in which PVOH (polyvinyl alcohol) is blended is performed, and a 2 μm thick SiO ₂ blended PVO is dried on a PET film.
H coating was performed. Coated P
Oxygen permeability of the ET film ^4cc / m 2 · 24hrs
However, the coating film was poor in water resistance and 1
Oxygen permeability by absorbing moisture under 100% relative humidity was increased to ^65c / m 2 · 24hrs. Oxygen permeability Doing pulse irradiation of an excimer laser with a wavelength of 248nm in the coating film is caused to fall to ^2cc / m ² · 24hrs, the coating SiO ₂ and PVOH crosslinking reaction does not absorb moisture and improve and water resistance progresses Formed, 100
% Oxygen permeability under a relative humidity 4cc ^/ m 2 · 24
hrs.

[0016]

EXAMPLE 7 Oxygen permeability 145cc ^/ m 2 · 24hrs
Is coated with a commercially available mixed solution of water glass and PVOH on a biaxially stretched PET film having a thickness of 12 μm.
3μm dry glass blended PVO on film
H coating was performed. Although the oxygen permeability of the PET film was reduced to 16 cc / m ² · 24 hrs, the coating film was poor in water resistance, and absorbed water at 100% relative humidity to obtain an oxygen permeability of 72 c / m ² ·.
Rose to 24 hrs. Wavelength 248 for coating film
When excimer laser pulse irradiation is performed, the oxygen permeability is reduced to 6 cc / m ² · 24 hrs, a water glass and PVOH cross-linking reaction proceeds, a water resistance is improved, and a film that does not absorb moisture is formed. % oxygen permeability under a relative humidity was 12cc ^/ m 2 · 24hrs.

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Claims (9)

[Claims] 1. A plastic material having a surface layer provided on an inner surface, an outer surface, or an inner and outer surface of a plastic, and irradiating at least one surface of the surface layer with a laser to improve gas barrier properties. 2. The plastic of claim 1 is a film or sheet alone, and a package such as a plastic container, a bottle, a cup, a tray, and a cap. 3. A film packaging bag, a film lid material, a paper / plastic composite packaging bag, a paper / plastic composite paper carton, and a paper / plastic composite comprising the plastic film or sheet having improved gas barrier properties according to claim 1. Packaging such as trays, paper / plastic composite cups and lids. 4. The surface layer according to claim 1, wherein the surface layer is aluminum,
Single or mixed metal heating evaporation film of gold, copper, zinc, nickel, tin, indium, zirconium, titanium, etc. 5. A heat-deposited film of a single or mixed metal oxide such as silicon oxide, aluminum oxide, magnesium oxide, and zirconium oxide as the surface layer according to claim 1. 6. The surface layer according to claim 1, wherein the inorganic compound is a single or mixed inorganic compound such as an inorganic compound obtained by hydrolyzing an alkoxy metal compound, a particulate inorganic compound, a tabular inorganic compound, ceramic, glass, water glass and clay. Coating film. 7. The surface layer according to claim 1, wherein a single or mixture of a compound of an organic substance and a metal such as an alkoxy metal compound, an alkyl metal compound, a chelate compound or the like is converted into a plasma by electromagnetic waves or radiations such as ultraviolet rays, high frequency waves and microwaves. Single or mixed metal oxide deposited film. 8. The surface layer according to claim 1, wherein a hydrocarbon such as acetylene, ethylene, hexane, benzene, toluene, or cyclohexane or an organic compound such as triazine, melamine, or methylolmelamine is irradiated with ultraviolet light, high frequency,
Amorphous and crystalline carbon, hydrogenated carbon, or organic vapor-deposited films that have been deposited by being converted into plasma using electromagnetic waves or radiation such as microwaves. 8. The surface layer according to claim 1, which is a single or mixture of polymers such as PVOH (polyvinyl alcohol), EVOH (ethylene vinyl alcohol copolymer), and PAA (polyacrylic acid). 9. The surface layer according to claim 1, wherein the surface layer is PVOH or EVO.
A mixture of an inorganic compound obtained by hydrolyzing a polymer such as H or PAA and an alkoxy metal compound, a particulate inorganic compound, a tabular inorganic compound, or an inorganic compound such as ceramic, glass, water glass, or clay.