JPH0413128A - Chromic film - Google Patents

Abstract

PURPOSE:To enhance photochromogenizing velocity at the time of being wet and to prevent clouding of a thermochromic material part at the time of low temperature by forming a photochromic layer and a thermochromic layer on one side of a support film. CONSTITUTION:A clouding preventing layer 5 is formed on the side of the support film 2 reverse to the photochromic layer 3 and the thermochromic layer 4 formed on the same side. The layer 3 is formed by mixing silver halide and copper halide or silver or copper metal, dissolving the mixture, and cooling it, and vapor depositing the obtained eutectic mixture. The layer 4 is formed by mixing a binder with a compound to be allowed by temperature change to develop color and to be restored to an initial state temperature change, such as fluorene and phenylmethane type reversible thermochromic compounds, and coating with the mixture or spraying it, and the layer 5 is formed by cross- linking a hydrophilic monomer with a polymer, thus permitting the photochromogenizing velocity at the time of being wet to be enhanced and the thermochromic layer to be prevented from clouding at the time of low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chromic film having photochromic properties, thermochromic properties, and antifogging properties.

[Prior Art] Films that have both photochromic properties and anti-fog properties can be used on car windows, building windows, and eyes! It is already known as a film that can be used by adhering it to lenses for camera use, etc. In order to impart photochromic properties, it is possible to mix an inorganic photochromic substance containing silver chloride into the thermoplastic resin, provide an intermediate layer of photochromic glass powder and laminate it, or add an organic photochromic substance such as spiropyran. A synthetic resin with dispersed particles was used.

On the other hand, thermochromic products that use thermochromic substances clearly change color due to temperature changes and have a narrow range of discoloration temperatures. It is used in fields such as indicating the appropriate storage temperature for chilled or cold sausage products and checking the state of storage.

However, there is no known antifogging film that has both photochromic and thermochromic properties.

[Problems to be Solved by the Invention] Conventional films using photochromic substances have a slow light coloring rate when wet, and thermochromic substances using thermochromic substances have the problem of becoming cloudy in low temperature ranges.

[Means for solving the problem] As a result of intensive research, we have developed a film that has a fast photocoloring rate even when wet and does not cloud the non-thermal material area even at low temperatures.
Photochromic and thermochromic properties that are durable and have anti-fog properties even in humid and low-temperature environments by forming an anti-fog layer on the opposite side of the support film from the chromic layer on which the photochromic layer and thermochromic layer are formed. The inventors discovered that it is possible to obtain a film with a high viscosity, and came up with the present invention.

The photochromic layer formed on the support can be formed by mixing a silver halide such as silver chloride, silver bromide, silver iodide, a copper halide, or a single substance of silver or copper and cooling the mixture. SIR, spiropyran-based compounds, fulchito-based compounds, fulgide-based compounds, dihydropyrene-based compounds, indigo-based compounds, bipyridine-based compounds, aziridine, polycyclic aromatic compounds, which are formed by vapor-depositing the fused mixture onto a film using a vacuum evaporation method; It is formed by a thin film of a mixture of azobenzene, salicylidene aniline compounds, xanthine compounds, oxazine compounds, and diarylethene compounds with a binder.

As a binder, halogenated vinyl monomers such as vinyl chloride and vinylidene chloride, styrene and its derivatives, etc.
1 vinyl ester monomer such as vinyl acetate Allyl alcohol and allyl esters, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid or fumaric acid, ester derivatives of the above unsaturated carboxylic acids , concave nitrile derivatives or acid amide derivatives Acid amide derivatives of the above unsaturated carboxylic acids (&
N-methylol derivative or N-alkylmethylol ether derivative glycidyl acrylate, glycidyl methacrylate allyl glycidyl ether, vinyl isocyanate, allyl isocyanate, 2-hydroxyethyl acrylate or methacrylate, 2-
Hydroxypropyl acrylate or methacrylate, ethylene glycol mono-acrylate or methacrylate, ethylene glycol di-acrylate or methacrylate, maleic anhydride, itaconic anhydride, methyl vinyl ketone, methyl cellulose, butadiene, ethylene, propylene, dimethylaminoethyl ester Homopolymers of monomers such as methacrylate, vinylpyridine, vinylpyrrolidone, t-butylaminoethyl methacrylate, monoallyl ether of polyhydric alcohol, or any copolymers thereof, polyvinyl alcohol, polyvinyl butyral, polyvinyl Formal, phenolic resin, polyester resin, polyamide resin, epoxy resin, aminoplast resin, polyurethane resin, natural or synthetic rubber derivatives, nitrified cotton, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, etc. cellulose derivatives. Others may be selected from natural or processed resins.

The thin film can be formed by applying a mixture of a photochromic substance and a binder by brushing, spatula coating, spray coating, dipping coating, flow coating, gravure reverse method, triple reverse method, gravure direct method, etc. roll coating method,
Coating is done using conventional methods such as reverse roll coating, kiss coating, plate coating, smooth coating, barcode coating, air knife coating, and spinner coating.

In addition, thermochromic materials include irreversible types (dye-based, inorganic-based, metal complex salt-based) that cannot be returned to their original state if they change color due to temperature changes, and thermochromic materials that change color due to temperature changes. Reversible types (dye type, cholesteric liquid crystal type) that can return the chromink substance to its original state by subsequent temperature changes, and those that lose crystal water due to thermal decomposition due to heating, but can take in crystal water after cooling. Semi-reversible type that recovers to its original state (
Examples of reversible types include fluorane, phenylmethane compounds, indolylphthalide, spiropyran, leucouramines, and acyl or arylauramines.

The thermochromic material IS is formed on a support by coating or spraying the mixture with a binder made of various synthetic resins, etc., in the same manner as the method for forming the photochromic material thin film described above.

If the support covering these chromic layers has sufficient mechanical strength to support the chromic layer,
Any material can be used depending on the use of the chromic material. Examples include polyesters such as polyester terephthalate, polyolefins such as polyethylene and polypropylene, polyamides such as nylon, and films of synthetic resins such as polycarbonate, polyacrylate, polystyrene, and polyvinyl chloride.
Also, depending on the purpose of use, you can choose from thin films, sheets and boards.

On the other hand, an antifogging layer made of an antifogging thin film is formed on the side of the support opposite to the side on which the thin film of goji mink substance is formed.

The antifogging layer can be formed by crosslinking a polymer with a hydrophilic hexamer, and the crosslinking is performed using radicals generated by irradiation with an electron beam or the like.

The method for forming the antifogging layer will be explained below.

In addition to using hydrophilic monomers alone for crosslinking,
(b) Using a hydrophilic monomer and a surfactant in combination, (b)
A combination of a hydrophilic monomer and a cross-linking seven-mer, (c) a combination of one hydrophilic monomer, one cross-linking seven-mer, and one surfactant, (
d) Hydrophilic crosslinking monomer (e) Hydrophilic crosslinking monomer and surfactant used in combination, (f) Hydrophilic monomer and hydrophilic crosslinking monomer used in combination, (g) Hydrophilic monomer, hydrophilic Any combination, such as the combined use of a crosslinkable monomer or a surfactant, may be used.

As the polymer, both non-functional polymers and functional polymers can be used.

As the non-functional polymer, polyacrylic acid alkyl ester, polymethacrylic acid alkyl ester, polyurethane, polyester, polyacrylonitrile 1, polyvinylpyrrolidone, etc. can be used.

Furthermore, a hydrophilic group may be introduced in advance into the non-functional polymer in order to improve compatibility with the hydrophilic monomer to be crosslinked. This is a copolymer with a hydrophilic monomer (hydrophilic monomer) having a hydrophilic group, which will be described later. The ratio of the hydrophilic hexamer to the non-functional polymer is 50 mol % or less, and if it exceeds this, the water resistance of the resulting membrane decreases.

Furthermore, derivatives of polyvinyl alcohol such as partially saponified polyvinyl alcohol, polyvinyl butyral, and polyvinyl alcohol, and cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and hydroxypropyl cellulose can also be used. can.

On the other hand, a functional polymer is a polymer having a functional group that causes a crosslinking reaction when exposed to ionizing radiation. Examples of the functional group include an acryloyl group, a methacryloyl group, an allyl group, and an epoxy group.
A ratio of 1 functional group per 0oO is desirable, and when the ratio is less than 1 per molecule jlloo00, there is almost no crosslinking effect due to the functional group, and when it exceeds 1 per 300 molecular weight, the crosslinking density becomes too high. Examples of functional polymers include urethane acrylate, polyester acrylate, epoxy acrylate, etc., and copolymers of acrylic acid alkyl ester and 2-hydroxyethyl acrylate with acrylic chloride or 2-hydroxyethyl acrylate and diisocyanate in the hydroxyl groups. A copolymerization method in which acryloyl is introduced by adding alkyl esters in a one-to-one ratio.A copolymerization method in which glycidyl methacrylate is added to the carboxyl group of a copolymer of acrylic acid alkyl ester and acrylic acid.Acrylic acid is added to the remaining hydroxyl groups of polyvinyl butyral. A 1:1 adduct of chloride or 2-hydroxyethyl acrylate and diisocyanate can be used.

The above-mentioned polymer may be in the form of an oligomer, but from the viewpoint of film-forming properties, it is preferable that the molecular weight is 1,000 to 300,000 on average based on It weight.

Hydrophilic 7-termers are 7-termers containing hydrophilic groups such as hydroxyl group, carboxyl group and its metal salt, amide group, imide group, sulfonic acid group, ammonium base, phosphoric acid group, etc., such as 2-hydrocoxyethyl acrylate, methacrylic acid- 2-HFD xyethyl, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylic acid, methacrylic acid, metal acrylate, metal methacrylate, acrylamide, methacrylamide, dimethylaminopropylacrylamide, dimethylamino Propylmethacrylamide, N-acryloylmorpholine, N-methylolacrylamide, N-methylolmethacrylamide, t-butylmethacrylamide,
N-methoxymethylacrylamide, [-ethoxymethylacrylamide, N-n-butoxyacrylamide, N-N-dimethylacrylamide, N-N-dimethylamidepropylacrylamide, N-N-dimethylaminopropylmethacrylamide, polyethylene glycol monomethacrylate, Examples include glycerol, monomethacrylate 2-acrylamido-2-methylpropanesulfonic acid, methacrylamidepropyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and mono(2-methacryloyloxyethyl) acid phosphate.

Crosslinking polymers are monomers that have two or more groups that easily become radicals when irradiated with electron beams, such as acrylic coils, methacryloyl groups, allyl groups, and epoxy groups, and both the backbone polymer and the hydrophilic monomer are crosslinked. To improve the crosslinking density of the entire membrane, increase membrane strength, and prevent unreacted hydrophilic monomers from remaining.

Such crosslinking monomers include ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, 1,6-hexanethiol dimethacrylate,
Glycidyl methacrylate, 2,2-bis(4-(acryloxyjethoxy)phenyl)propane, 2,2
-bis(4-(methacryloxyjethoxy)phenyl)
Bifunctional monomers such as propane, 2.2-bis(4-(acryloxypolyethoxy)phenyl)propane, 2.2-bis(4-(methacryloxypolyethoxy)phenyl)propane, trimethylolpropane trimethacrylate, etc. Examples include trifunctional monomers and other polyfunctional monomers such as tetramethylolmethanetetraacrylate and dipentaerythritol hexaacrylate.

Hydrophilic crosslinking monomers include hydroxyl groups, carboxyl groups and their metal salts, amide groups, imide groups, sulfonic acid groups and their metal salts, ammonium bases, hydrophilic groups such as phosphoric acid groups, and acryloyl groups, methacryloyl groups, allyl groups, epoxy groups, etc. A monomer that has two or more crosslinkable functional groups that easily become radicals when irradiated with radiation.

Examples of such hydrophilic crosslinking monomers include glycerol di(meth)acrylate, polyethylene glycol diglycidyl ether (meth)acrylate, polypropylene glycol diglycidyl ether di(meth)acrylate, and neopentyl glycol diglycidyl. Acrylic acid and diol diglycidyl ethers such as ether di(meth)acrylate, glycerin diglycidyl ether di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, and trimethylolpropane triglycidyl ether di(meth)acrylate. 1゛2 adduct of Pentaerythritol-derived E such as pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc. Methylenebis(meth)acrylamide, acrylamide/glyoxal adduct, acrylamide/methylolethylene urea condensate, 1. 3. 5-
1 acryloyl hexahydro S-triazine, N,
N-diallylacrylamide, acrylamide
Methylolmelamine condensate, acrylamide/methyloltriazone condensate, acrylamide/methylolhydantoin condensate, acrylamide/methylolurea, N
.

Examples include acrylamide derivatives such as N-diallylacrylamide.

The antifogging layer of the present invention can also contain a surfactant. The surfactant has the effect of imparting antifogging properties by gradually leaching out from the hydrophilic film to the surface. Any anionic, nonionic, or cationic surfactant can be used as long as it has good compatibility with the composition consisting of the above components constituting the antifogging layer.

Examples of anionic surfactants include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkyl sulfosuccinate ester salts, alkyl phosphate ester salts, naphthalene sulfonic acid-formalin condensates, and polyoxyethylene. There are alkyl sulfate ester salts, etc. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene alkyl amine. , glycerin fatty acid ester, oxyethylene-oxypropylene block polymer, etc., and cationic surfactants include alkylamines, quaternary ammonium salts, etc.

When forming the antifogging layer of the present invention, 5 to 200 parts by weight of the hydrophilic hexamer is added per 100 parts by weight of the polymer. 5
If it is less than 2 parts by weight, sufficient hydrophilicity will not be imparted;
If the value exceeds 00, the water resistance of the film decreases. The preferred content of hydrophilic monomer is 20 to 150 parts by weight.

The amount of crosslinking monomer is 1 to 300 per 100 parts by weight of polymer.
Parts by weight. If it is less than 1 part by weight, the crosslinking of the unreacted hydrophilic monomer will be insufficient, and if it exceeds 300 parts by weight, the crosslinking density of the entire product will be too high. In particular, when the polymer has no functional group, the content of the crosslinking monomer is preferably 5 to 300 parts by weight, more preferably 5 to 200 parts by weight.

In addition, when the polymer has a functional group, the content of the crosslinking compound is preferably 1 to 200 parts, and 5 to 200 parts.
More preferably, the amount is 100 ffi parts.

The hydrophilic crosslinking monomer is used in an amount of 1 to 200 parts by weight per 10 parts of the polymer. If the amount of the polymer is less than 100 parts by weight, sufficient hydrophilicity and crosslinking properties will not be imparted,
On the other hand, if it exceeds 2001 [(extension part), the water resistance of the membrane decreases and the degree of crosslinking becomes too high.The content of the hydrophilic crosslinking monomer is preferably 1 to 100 parts.

When a surfactant is added, the amount is 100 parts by weight or less per part of polymer 10011. If it exceeds 100 parts by weight, leaching of the surfactant becomes too large, so the preferred content is 1 to 50 parts by weight.

When forming an antifogging layer, a solvent may be appropriately contained in a composition made of an appropriate combination of the above components. The solvent simply improves the fluidity of the composition. It is preferable for forming the antifogging layer of the present invention because it not only acts as a layer but also causes the hydrophilic monomer to float on the surface of the coating film. Solvents that can be used include alcohols such as methanol, ethanol, isopropanol, methyl cellosolve, and ethyl cellosolve, ethers such as tetrahydrofuran, ketones such as methyl ethyl ketone, acetone, and methyl isobutyl ketone, ethyl acetate, and butyl acetate. etc., aromatic hydrocarbons such as toluene, xylene, etc., or mixed solvents thereof.

The amount of solvent added varies depending on the film formation method, but when forming a coating film by coating, the solid content in the composition is 5 to 50%.
%, preferably 5 to 30% by weight.

-For boat fishing, the amount of solvent added is 60% per 100 parts by weight of polymer.
00 parts by weight or less.

An antifogging coating film can be formed by the following method using a composition of the above components.

First, a composition adjusted to an appropriate viscosity is applied onto the surface of a support film by a roll coating method such as a gravure reverse method, a three-pole reverse method, a gravure direct-reverse method, or a four-pole reverse method. The coating film of the composition formed on the support film is dried while being heated with a dryer or the like in order to evaporate the solvent. If the heating temperature is too high, the 7mers will also evaporate, so the maximum temperature should be around 140°C.

The antifogging coating film formed as described above tends to consist of a monomer-rich phase in which the monomer is lifted to the surface and a polymer-rich layer.

By exhibiting such orientation, a relatively large number of hydrophilic groups are present on the surface, and an antifogging coating film supported by a polymer skeleton portion with high water resistance and high mechanical strength can be obtained.

Next, this antifogging coating film is irradiated with an electron beam. As the irradiation method, any method such as an electron curtain method or a beam scanning method can be used. Irradiation with electron beams makes the polymer crosslinkable with or without functional groups, and the polymers crosslink to the polymer by graft or block polymerization. The energy of the irradiated electron beam is about 150 to 200 KeV, but the irradiation amount varies depending on the composition of the composition, the desired crosslinking density, etc.

The more functional groups there are in the polymer and the more crosslinkable monomers there are, the fewer irradiation lids are needed, and in order to increase the crosslinking density, it is necessary to increase the amount of irradiation.

In particular, if the amount of hot water containing the surfactant is too high, the leaching of the surfactant will be insufficient and the antifogging effect will be reduced, so it is important to control the amount of irradiation.

For these reasons, the irradiation dose is generally 0. 5 to 2
If it is less than 0.5 Mrad, unreacted monomer may remain, and if it exceeds 20 Mrad, the crosslinking density will become too high.

The antifogging layer formed as described above has a unique structure in which the polymer skeleton is crosslinked with hydrophilic monomers, hydrophilic crosslinking monomers, etc., and the hydrophilic groups are concentrated on the surface of one layer. What it does is it has good anti-fog properties and mechanical strength.

Note that it is preferable to form the antifogging layer before forming the layer of thermochromic material or photochromic material from the viewpoint of preventing adverse effects on the chromic material by electron beams.

The chromic film of the present invention utilizes a thermochromic material that exhibits a discoloration range near the temperature at which food is stored frozen, and when used as a packaging material for frozen foods, it can indicate the preservation state or freshness of frozen foods. becomes possible.

[Effects] A photochromic layer and a thermochromic layer are formed on one side of the support film, and an anti-fog layer is formed on the other side, so even in a humid environment, the photochromic layer and thermochromic layer can be coated within 1 minute. It is possible to perform various functions.

[Example code] The present invention will be further explained below with reference to the drawings.

FIG. 1 shows the chromic mink film of the present invention. The chromic film 1 has a photochromic layer 3 and a thermochromic layer 4 laminated on one side of a support film 2.
An anti-fog layer 5 is provided on the opposite side to the surface on which these chromic layers are laminated.

It is optional whether the photochromic layer or the thermochromic layer should be on the support film side.

When the obtained Cucomic film is used for transportation and display purposes, it is preferable to place the thermochromic layer on the support film side.

A polyester film (manufactured by Toshi ■) was used as an example support film.
Lumirror T-60 (thickness: 38 μm) was used, and one side of it was coated with the composition (100 parts by weight of acrylic polymer, 100 parts by weight of 2-hydroxyethyl methacrylate, 10 parts by weight of diethylene glycol dimethacrylate) 1 f Emulgen 106 (manufactured by Kao Corporation). 5 weight 侃 methyl 7 rusolve 5
00 heavy background part) was applied using a roll coater and dried with a dryer to form an 8 μm thick anti-fog layer.9 Then, it was cured by irradiating 5 Mrad of 175 KeV electron beam using an electron curtain type EB device (manufactured by ESI). I let it happen.

Polyvinyl butyral 3 on the back side of the polyester film
A photochromic resin consisting of 0 parts by weight of ethanol, 40 parts by weight of toluene, and 3 parts by weight of spiropyran was barcoded and dried and solidified at 100° C. for 5 minutes to form a photochromic layer.

On the photochromic layer, 10 g of cholesteric l (K crystal dissolved in chloroform) having thermochromic properties was added.
, 15 ml of 8% gelatin aqueous solution. Gum arabic 8%
Emulsify 15ml of aqueous solution at 40℃, add acetic acid and adjust the pH.
After adjusting to 4, add 100 ml of distilled water and 1 ml of 30% formalin.
A liquid crystal ink in which liquid crystal microcapsules obtained by cooling to 5°C were dispersed in a binder of polyvinyl alcohol, an aqueous alkyd resin, and acrylamide was applied.

When the obtained film was used as part of a food packaging film, the storage temperature was clearly indicated even when wet. Furthermore, the photochromic layer exhibited clear decolorization and color development even when wet.

[Effects of the Invention] The chromic film obtained in the present invention exhibits clear photocoloring, temperature coloring, and decolorization when wet, has fast photocoloring and decolorization speeds, and has good antifogging properties.

It can be adhered to car window glass, building window glass, etc. as coating decorative materials that require temperature indication, optical-related products, etc., and its effects are tremendous.

In addition, when a film with a photochromic material layer that absorbs ultraviolet rays and a temperature-indicating material layer that changes color near the storage temperature of the frozen food is used for packaging frozen foods, it is possible to determine the contents from the outside. However, since the photochromic layer absorbs ultraviolet rays, it is possible to prevent food from deteriorating due to ultraviolet rays, and it is also possible to check the storage state of frozen foods using thermostats.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of the chromic film of the present invention. Chromic film...1 Support film...2 Photochromic layer---3 Thermochromic layer...4 Anti-fog layer...5 Patent applicant Dainippon Printing Agent Co., Ltd.

Claims (2)

[Claims] (1) A chromic film characterized by having a photochromic layer and a thermochromic layer on one side of the support film and an antifogging layer on the other side. (2) The chromic film according to claim 1, wherein the antifogging layer is a polymer crosslinked with a hydrophilic monomer using an electron beam.