JPH09226079A - Surface curable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the property of adhesion not only between a base material and a laminated film but also between the base material and a surface curable layer, and the durability by providing a laminate with the surface curable layer formed through a laminated film of a structure which is phase-separable in the thickness direction and also a mixed layer of each of layers formed in the separation interface. SOLUTION: In a laminate with a surface curable layer B formed through a laminated film a provided at least, on one of the faces of a polyester film, a phase-separable structure is provided in the thickness direction of the laminated film A, and a mixed layer of each of the layers is formed in a separation interface. The preferable structure of the polyester is composed of ethylene terephthalate as a main constituent from a viewpoint of quality and economy, and the preferable thickness is 1-300μm. In addition, the preferred resins used for the laminated film are an acrylic resin and a polyester resin with their respectively different solubility parameters. Further, a water resin coating liquid is applied to the laminated film, and is stretched and thermally treated to undergo a crystal orientation process. The best suited surface curable layer B is an active linear curable acrylic resin layer in terms of hardness, curing properties and flexibility.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a high surface hardness,
Regarding the polyester film laminate with excellent abrasion resistance,
Specifically, by providing a surface-cured layer on the base polyester film via a laminated film, the surface-cured layer has excellent durability,
The present invention relates to a surface-cured film that can be used for a touch panel, a display attached to glass or a metal plate, a label, a sticker, an OHP, a card, a courier slip, an image-receiving paper for a printer, and the like.

[0002]

2. Description of the Related Art Biaxially oriented polyester films are excellent in mechanical properties, dimensional stability, heat resistance, transparency, electrical insulation properties, and the like, so that they are used for magnetic recording materials, packaging materials, electrical insulation materials, various types of materials, etc. It is widely used as a base film for many applications such as photographic materials and graphic arts materials. However, since the surface hardness of polyester film is low and the abrasion resistance is insufficient, for example, the film surface is easily damaged by contact with other hard objects, friction, scratching, etc. May significantly reduce the product value or become unusable in a short period of time.

For this reason, a method is known in which a surface-hardened layer having excellent scratch resistance and abrasion resistance is provided on the base polyester film, but the surface of the polyester film is highly crystallographically oriented. It has a drawback that it has poor adhesion to the hardened layer and the surface hardened layer peels off, resulting in substantially poor durability. Therefore, it has been proposed in the past to provide the polyester film surface with easy adhesion by various methods.

For example, a surface activation method of corona discharge treatment in various gas atmospheres, plasma treatment, ultraviolet irradiation treatment, flame treatment, etc. on a polyester film surface, acid, alkali, trichloroacetic acid, amine, phenols, etc. A surface etching method using chemicals, or a method in which various resins such as polyester, acrylic, polyurethane, and acrylic graft polyester are provided as a primer layer on the film surface (JP-A-55-15825, JP-A-5-15825).
No. 8-78761, JP-A-60-248232, JP-A-1-171988, etc.) are already known. In particular, a method of providing easy adhesion by providing the primer layer by coating, that is, subjecting the polyester film before the crystal orientation is completed corona discharge treatment, if necessary, applying a coating liquid containing the resin component, A method of completing the crystal orientation by performing stretching and heat treatment after drying (in-line coating method) is used in the art.

For example, a method has been proposed in which a coating layer made of a urethane resin is provided on the surface of a polyester film, and a surface hardened layer is provided on the surface (Japanese Patent Laid-Open No. 62-263237).

[0006]

However, the above-mentioned prior art has the following problems.

When a water-soluble or water-dispersible acrylic resin is applied to a polyester film to impart adhesiveness, the adhesiveness with the surface-hardened layer is excellent, but the adhesion with the base polyester film is excellent. However, there is a drawback in that the durability becomes poor and the surface hardened layer is inferior in durability.

Further, when a water-soluble or water-dispersible polyester resin or a water-soluble or water-dispersible urethane resin is applied on a polyester film, the adhesiveness with the base polyester film is excellent, but the surface is hardened. There is a drawback that the adhesiveness with the layer cannot be obtained and the surface-hardened layer is inferior in durability.

The present invention eliminates these drawbacks, and not only the adhesiveness between the base polyester film and the laminated film,
It is intended to provide a surface-cured film which is excellent in adhesiveness with a surface-cured layer and has excellent durability.

[0010]

The present invention provides a laminate having a surface-hardened layer (B) provided via a laminate film (A) provided on at least one surface of a polyester film,
The surface-hardened film is characterized in that the laminated film (A) has a phase-separated structure in the thickness direction and a mixed phase of each phase is present at the phase-separated interface.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the polyester constituting the polyester film is a generic term for polymers having an ester bond as a main bonding chain of a main chain. Preferred polyesters include ethylene terephthalate and ethylene- 2,6-naphthalate, butylene terephthalate, ethylene-α, β-bis (2-chlorophenoxy)
Those having at least one component selected from ethane-4,4'-dicarboxylate and the like as a main component can be used. One of these components may be used alone or two or more of them may be used in combination. Among them, it is preferable to use a polyester containing ethylene terephthalate as a main component when comprehensively judging quality, economy and the like.
In addition, heat resistance and rigidity are required for applications in which heat acts on the base material such as recording image receiving sheets for electrophotography, thermal recording, various printing, etc., or applications in which resin shrinks during curing such as UV curable ink. Excellent polyethylene-2,6
-Naphthalate is more preferred.

Further, these polyesters further contain a part of other dicarboxylic acid components and diol components, preferably 2 parts.
About 0 mol% or less may be copolymerized.

Further, in this polyester, various additives such as antioxidants, heat resistance stabilizers, weather resistance stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, An antistatic agent, a nucleating agent, a cross-linking agent, etc. may be added to the extent that the characteristics are not deteriorated.

The intrinsic viscosity of the above-mentioned polyester (25 ° C.)
Measured in o-chlorophenol) of 0.4-1.2.
dl / g is preferred, more preferably 0.5-0.8d
Those in the range of 1 / g are suitable for carrying out the present invention.

The polyester film using the above polyester is preferably biaxially oriented when the laminated film is provided. Biaxially oriented polyester film generally means an unstretched polyester sheet or film in the lengthwise direction and the widthwise direction, respectively.
It is drawn to about 5 times, then heat-treated to complete the crystal orientation, and shows a biaxial orientation pattern in wide-angle X-ray diffraction. The biaxial stretching may be longitudinal or transverse sequential stretching or biaxial simultaneous stretching. Also, vertical,
After the transverse stretching, it may be re-stretched in either the longitudinal or transverse direction.

The thickness of the polyester film is not particularly limited and may be appropriately selected depending on the application, but is usually 0.5 to 5
The thickness is 00 μm, preferably 1 to 300 μm. Further, the obtained films can be laminated by various methods to form a thicker film. In addition, a white polyester film can be preferably used as a base material film for label applications, image receiving sheet applications, card applications such as prepaid cards and IC cards. The white polyester film is not particularly limited as long as it is a polyester film colored in white,
The whiteness is preferably 85 to 150%, more preferably 9
0 to 130%, and the optical density is preferably 0.5 to
5, and more preferably 1.2 to 3. For example,
Taking a magnetic recording card as an example, when a base film having a low degree of whiteness is used, the coloring of the magnetic recording layer and the like easily penetrates and the aesthetic appearance of the printed layer on the surface is easily impaired. The reason for this is that no sufficient light reflection is obtained, the whiteness is reduced when viewed with the naked eye, the opposite surface is affected, or a trouble may occur depending on the measuring method when reading the magnetic recording.

The method for obtaining such optical density and whiteness is not particularly limited, but usually, it can be obtained by adding a resin incompatible with inorganic particles or polyester. The amount to be added is not particularly limited, but in the case of inorganic particles, it is preferably 5 to 35% by weight, more preferably 8 to 2%.
5% by weight. On the other hand, when an incompatible resin is added, it is preferably 5 to 35% by volume, more preferably 8 to 2%.
5% by volume.

The inorganic particles are not particularly limited, but preferably have an average particle size of 0.1 to 4 μm, more preferably 0.3 to 4 μm.
Inorganic particles of 1.5 μm or the like can be used as a typical one. Specifically, barium sulfate, calcium carbonate, calcium sulfate, titanium oxide, silica, alumina, talc, clay, etc., or a mixture thereof can be used, and these inorganic particles include other inorganic compounds such as calcium phosphate, titanium oxide, mica. , Zirconia, tungsten oxide, lithium fluoride, calcium fluoride and the like. Further, among the above-mentioned inorganic particles, the Mohs hardness is preferably 5 or less, and more preferably 4 or less, the whiteness is further increased, which is desirable.

The resin which is incompatible with the above-mentioned polyester is not particularly limited, but in the case of mixing with polyethylene terephthalate or polyethylene-2,6-naphthalate, for example, acrylic resin, polyethylene, polypropylene, modified olefin resin, A polybutylene terephthalate resin, a phenoxy resin, a polyphenylene oxide, or the like can be used, and naturally, the inorganic particles described above may be used in combination. For example, in particular, a white polyester film having a specific gravity of 0.5 to 1.3, which has inorganic particles or a resin incompatible with polyester and is biaxially stretched and has a cavity inside, has good printability. preferable.

In the present invention, the laminated film provided on the polyester film surface must be firmly adhered to both the base polyester film and the surface-hardened layer. In general, when a resin having excellent adhesiveness to a surface-hardened layer is used as the laminated film, the laminated film is inferior in adhesiveness to a base film and also excellent in adhesiveness to a base film. When a resin is used, the laminated film tends to have poor adhesion to the surface-hardened layer. For example, when an acrylic resin is used alone as a laminated film, the acrylic resin layer has excellent adhesiveness with a surface-hardened layer, but has poor adhesiveness with a base film, and a polyester resin or urethane. When a resin or the like is used alone, the resin layer has excellent adhesiveness with the substrate film, but has poor adhesiveness with the surface-hardened layer.

In order to solve such conflicting phenomena,
The inventors of the present invention use two kinds of resins and control the drying conditions when a laminated film is formed so that the laminated film has a phase-separated structure in the thickness direction, and the phase-separated interface has each phase separated phase. It was found that there is a mixed phase of. By applying the laminated polyester film having such a phase-separated structure to the surface-cured film, not only the adhesiveness between the base polyester film and the laminated film, but also the adhesiveness with the surface-cured layer is excellent and durability is improved. An excellent surface-hardened film can be provided.

That is, in the surface-cured film of the present invention, two kinds of resins having different solubility parameters are used for the laminated film, and the drying conditions when the laminated film is formed are controlled so that the two kinds of resins are mixed with each other. The inventors have found that a so-called phase separation structure is adopted in which a resin having a small solubility parameter is formed on the gas phase side and a resin having a large solubility parameter is formed on the polyester film side by adopting a separation structure. Furthermore, it was found that a mixed phase of each phase is present at the interface between the surface layer and the intermediate layer of the laminated film, and in particular, when the mixed phase is present, the laminated film of the polyester film is a surface-cured layer. At the same time as being excellent in adhesiveness with the base film, the adhesiveness at the interface between both phases in the laminated film is also improved.

In the surface-cured film of the present invention, the resin used for forming the laminated film is not particularly limited as long as it is at least two kinds of resins having different solubility parameters. As the resin used, polyester resin, acrylic resin, urethane resin, polyolefin resin, polycarbonate resin, alkyd resin,
Epoxy resin, urea resin, phenol resin, vinyl chloride resin, vinyl acetate resin, fluororesin, silicone resin,
At least two kinds of resins selected from rubber-based resins, wax-based resins and the like.

Among them, acrylic resin and polyester resin, or acrylic resin and urethane resin are preferably used from the viewpoint of adhesiveness to both the polyester film and the surface-hardened layer. Particularly, in the present invention, acrylic resin and polyester resin are used. It is more preferable to use.

In the surface-cured film of the present invention, the acrylic resin used as a constituent component of the laminated film may be, for example, an alkyl acrylate or an alkyl methacrylate (as the alkyl group, a methyl group or an ethyl group) as a monomer component constituting the acrylic resin. Group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), 2 -Hydroxy group-containing monomers such as hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylacrylamide,
N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-
Amide group-containing monomers such as phenylacrylamide, N,
Amino group-containing monomers such as N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt). Etc.) and the like, or a monomer containing a carboxyl group or a salt thereof can be used.
Copolymerized with more than one species. Further, they can be used in combination with other types of monomers.

Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether, styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.).
Such as monomers containing sulfonic acid groups or salts thereof, such as crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) Monomers containing, maleic anhydride, monomers containing acid anhydrides such as itaconic anhydride, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane,
Alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride and the like can be used.

Further, as the acrylic resin which can be used in the present invention, a modified acrylic copolymer such as a block copolymer or a graft copolymer modified with polyester, urethane or epoxy can be used.

The glass transition point (Tg) of the acrylic resin used in the present invention is not particularly limited, but is preferably 0 to 90 ° C., more preferably 10 to 80.
° C. When an acrylic resin having a low Tg is used, the adhesiveness under high temperature and high humidity tends to be poor, and when it is too high, cracking may occur during stretching, which is not preferable. The molecular weight of the acrylic resin is preferably 100,000 or more,
More preferably, it is 300,000 or more in terms of adhesiveness.

Preferred acrylic resins used in the present invention include methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, glycidyl methacrylate, acrylic acid,
It is a copolymer or the like selected from acrylonitrile.

In the case of producing a laminated film in the surface-cured film of the present invention, it is possible to apply a water-based resin coating liquid to a polyester film before completion of crystal orientation, and stretch and heat-treat to complete crystal orientation. It is particularly preferable because it can be heat-treated at a high temperature and a more uniform thin film can be obtained. When the laminated film is formed by the above method, the acrylic resin is preferably an aqueous resin that can be dissolved, emulsified or suspended in water, from the viewpoint of environmental pollution and explosion proof. Such water-based acrylic resins are copolymerized with monomers having a hydrophilic group (acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof, etc.), emulsion polymerization using a reactive emulsifier and a surfactant, and suspended. It can be prepared by a method such as turbid polymerization or soap-free polymerization.

The polyester resin used as a constituent component of the laminated film in the surface-cured film of the present invention has an ester bond in its main chain or side chain, and is obtained by polycondensation of dicarboxylic acid and diol.

As the carboxylic acid component constituting the polyester resin, aromatic, aliphatic, or alicyclic dicarboxylic acids and polyvalent carboxylic acids having a valence of 3 or more can be used. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid,
1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxyethane-p, p'-dicarboxylic acid, phenylindanedicarboxylic acid and the like can be used. From the viewpoint of strength and heat resistance of the laminated film, these aromatic dicarboxylic acids are preferably 30 mol% or more of all dicarboxylic acid components,
It is more preferable to use 35 mol% or more, and most preferably 40 mol% or more. Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and 1,4-cyclohexane. Dicarboxylic acid, etc.
And their ester-forming derivatives can be used.

As the glycol component of the polyester resin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, 1,5-
Pentanediol, 1,6-hexanediol, 1,7
-Heptanediol, 1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol, 2,
4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3 -Methyl-1,5
-Pentanediol, 2,2,4-trimethyl-1,6
-Hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-
Cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2 -Norbornylidene)
Diphenol, 4,4′-dihydroxybiphenol,
o-, m-, and p-dihydroxybenzene, 4,
4'-isopropylidenephenol, 4,4'-isopropylidenebindiol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and the like can be used.

When the polyester resin is used as an aqueous resin coating solution, a compound containing a carboxylate group or a sulfone is used in order to improve the adhesiveness of the polyester resin or to facilitate the water solubility of the polyester resin. It is preferable to copolymerize a compound containing an acid base.
In particular, in applications where moisture-resistant adhesion is required, as the polyester resin constituting the laminated film, a compound containing a carboxylate group is used without copolymerizing a compound showing strong basicity represented by a sulfonate group. Copolymerization is desirable.

Examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1,
2,3,4-butanetetracarboxylic acid, 1,2,3,4
-Pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-
1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid,
1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ', 3,3'
-Diphenyltetracarboxylic acid, thiophene-2,3
It is possible to use 4,5-tetracarboxylic acid, ethylene tetracarboxylic acid, etc., or their alkali metal salts, alkaline earth metal salts, ammonium salts, but not limited to these.

Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4
-Sulfoisophthalic acid, 4-sulfonaphthalene-2,7
-Dicarboxylic acid, sulfo-p-xylylene glycol,
2-sulfo-1,4-bis (hydroxyethoxy) benzene and the like, or their alkali metal salts, alkaline earth metal salts, and ammonium salts can be used, but are not limited thereto.

Further, as the polyester resin which can be used in the present invention, a modified polyester copolymer such as a block copolymer or a graft copolymer modified with acryl, urethane, epoxy or the like can be used.

Preferred polyester resins include terephthalic acid, isophthalic acid, sebacic acid, trimellitic acid, pyromellitic acid, and 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene as acid components. -1,2-dicarboxylic acid, ethylene glycol as a glycol component, diethylene glycol, 1,4
-A copolymer selected from butanediol and neopentyl glycol.

In the surface-cured film of the present invention, the polyester resin used for the laminated film can be manufactured by the following manufacturing method. For example, a polyester resin composed of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as a dicarboxylic acid component and ethylene glycol and neopentyl glycol as a glycol component will be described. Terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene A first step in which a glycol or neopentyl glycol is directly esterified or a transesterification reaction between terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene glycol or neopentyl glycol is performed, and the reaction in this first step It can be produced by a method of producing by a second step in which the product is subjected to polycondensation reaction.

At this time, as the reaction catalyst, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc,
Antimony, germanium, titanium compounds and the like can be used.

As a method for obtaining a polyester resin having a large amount of carboxylic acid at the terminal and / or side chain,
JP-A-54-46294, JP-A-60-2090
73, JP-A-62-240318, JP-A-53-26828, JP-A-53-26829, JP-A-53-98336, and JP-A-56-11.
It can be produced by a resin obtained by copolymerizing a polyvalent carboxylic acid having a valence of 3 or more as described in JP 6718, JP 61-124684, JP 62-240318 and the like. It may be a method.

In the surface-cured film of the present invention, the intrinsic viscosity of the polyester resin used for the laminated film is not particularly limited, but it is preferably 0.3 dl / g or more, more preferably 0 in terms of adhesiveness. .35 dl /
g or more, and most preferably 0.4 dl / g or more. Glass transition point of water-based polyester resin (hereinafter
Tg) is preferably 0 to 90 ° C, more preferably 10 to 80 ° C. If the Tg is less than 0 ° C, the moisture-resistant adhesiveness will be poor, and if it exceeds 90 ° C, the resin film-forming property will be inferior, which is not preferable. Also,
The acid value of the water-based polyester resin is preferably 20 mgK
OH / g or more, more preferably 30 mgKOH / g or more is preferably used in terms of adhesiveness, particularly moisture-resistant adhesiveness.

By adding a melamine-based crosslinking agent to the above-mentioned acrylic resin or polyester resin, the laminated film according to the present invention has improved adhesiveness, particularly moisture-resistant adhesiveness. Of course, if the above-mentioned method of applying to the polyester film before crystal orientation is used, the effect becomes particularly remarkable.

In the present invention, the lamination ratio of the surface layer and the intermediate layer (surface layer / thickness ratio of the intermediate layer) is not particularly limited,
Usually, the ratio is preferably 2/98 to 95/5, more preferably 5/95 to 90/10, most preferably 10 /.
The range of 90 to 70/30 is excellent in terms of moisture-resistant adhesiveness.

By adding various crosslinking agents to the above-mentioned acrylic resin and polyester resin, the laminated film according to the present invention has improved adhesiveness, particularly moisture-resistant adhesiveness. Of course, if the above-mentioned method of applying to the polyester film before crystal orientation is used, the effect becomes particularly remarkable.

The cross-linking agent that can be used is not particularly limited, but may be a functional group present in the acrylic resin or polyester resin used in the present invention, such as a hydroxyl group, a carboxyl group, an amide group or a methylol group. As long as it can undergo a crosslinking reaction, typical examples are methylolated or alkylolated urea-based, melamine-based, acrylamide-based, polyamide-based resins, epoxy compounds, oxazoline-based, isocyanate compounds, aziridine compounds, various silane cups. Examples include ring agents and various titanate coupling agents. Among these, the addition of a melamine-based crosslinking agent and an oxazoline group-containing crosslinking agent is most preferable.

The melamine-based cross-linking agent is not particularly limited, but includes melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, and a compound partially or completely etherified by reacting a lower alcohol with methylolated melamine. , And mixtures thereof can be used. The melamine-based cross-linking agent may be either a monomer, a condensate composed of a dimer or higher polymer, or a mixture thereof. Examples of the lower alcohol used for etherification include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-
Butanol, isobutanol and the like can be used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and includes an imino group-type methylated melamine resin, a methylol group-type melamine resin, and a methylol group-type. Methylated melamine resins, fully alkylated methylated melamine resins, and the like. Among them, the methylolated melamine resin is the most preferable. Further, an acidic catalyst such as p-toluenesulfonic acid may be used in order to promote the thermal curing of the melamine-based crosslinking agent.

The oxazoline group-containing cross-linking agent is not particularly limited as long as it has an oxazoline group as a functional group, but from an oxazoline group-containing copolymer containing at least one kind of oxazoline group-containing monomer. The following can be used, and the adhesiveness can be improved.

Examples of the oxazoline group-containing cross-linking agent include JP-A-2-60941 and JP-A-2-9953.
7, JP-A-2-115238, JP-B-63
The copolymers or their derivatives described in JP-A-48884 can be used. Specifically, the following general formula

Embedded image (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. It is possible to use a copolymer obtained by copolymerizing the addition-polymerizable oxazoline represented by the formula (1) and at least one other monomer.

Examples of addition-polymerizable oxazolines include 2-vinyl-2-oxazoline and 2-vinyl-4-methyl-2.
-Oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-
Isopropenyl-4-methyl-2-oxazoline, 2-
Isopropenyl-5-ethyl-2-oxazoline and the like can be used, and one kind or a mixture of two or more kinds thereof can also be used. Among them, 2-isopropenyl-2-oxazoline is industrially easily available and suitable.

In the oxazoline group-containing cross-linking agent, the at least one other monomer used for the addition-polymerizable oxazoline is not particularly limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline. Methyl acid, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate,
Acrylic acid esters such as 2-ethylhexyl methacrylate, or methacrylic acid esters, unsaturated nitriles such as acrylonitrile and methacrylonitrile,
Unsaturated amides such as acrylamide, methacrylamide, N-methylolacrylamide and N-methylolmethacrylamide, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, olefins such as ethylene and propylene. , Vinyl chloride, vinylidene chloride, halogen-containing α-, β-unsaturated monomers such as vinyl fluoride, styrene, α-methylstyrene, and other α,
β-unsaturated aromatic monomers and the like can be used,
These can also use 1 type or a mixture of 2 or more types.

To obtain an oxazoline group-containing cross-linking agent using an addition-polymerizable oxazoline and at least one other monomer, polymerization may be carried out by an emulsion polymerization method, a solution polymerization method or the like.

In obtaining an oxazoline group-containing crosslinking agent using addition-polymerizable oxazoline and other monomers,
The amount of addition-polymerizable oxazoline used is 0.5
There is no particular limitation as long as it is in the range of ８０80% by weight or more. When the amount of the addition-polymerizable oxazoline used is less than 0.5% by weight, the crosslinking effect by the oxazoline group is small and the adhesiveness tends to be poor, and when it exceeds 80% by weight, the affinity with other resins to be used in combination and the crosslinking agent may increase. It tends to have poor polymerizability.

The amount of the melamine-based cross-linking agent added is not particularly limited, but in order to bring out the effect of the present invention more remarkably, based on 100 parts by weight of the solid content used as the coating liquid,
Preferably 0.5-40 parts by weight, more preferably 1-3
0 parts by weight, most preferably 2 to 20 parts by weight. When the amount of the melamine-based cross-linking agent added is small, the moisture-resistant adhesiveness tends to be poor, and when it is excessively added, on the contrary, the adhesiveness tends to be lowered. That is, when the acrylic resin and the polyester resin are mixed and used, preferably 0.5 to 40 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the total solid content of the acrylic resin and the polyester resin,
Most preferably, it is 2 to 20 parts by weight.

The addition amount of the oxazoline group-containing cross-linking agent is not particularly limited, but in order to bring out the effect of the present invention more remarkably, it is preferably 1 to 40 relative to 100 parts by weight of the solid content used as the coating liquid. Parts by weight, more preferably 3
-30 parts by weight, most preferably 5-20 parts by weight.
When the amount of the oxazoline group-containing crosslinking agent added is small, the moisture-resistant adhesiveness tends to be poor, and when it is excessively added, on the contrary, the adhesiveness tends to be lowered. That is, when the acrylic resin and the polyester resin are mixed and used, the total solid content of the acrylic resin and the polyester resin is 100 parts by weight.
It is preferably 1 to 40 parts by weight, more preferably 3 to 30 parts by weight, and most preferably 5 to 20 parts by weight.

By using the melamine-based crosslinking agent and the oxazoline group-containing crosslinking agent in combination, the adhesiveness can be improved.

In the surface-cured film of the present invention, it is preferable that the contact angle of the surface of the laminated film with water is 60 degrees or more and 90 degrees or less from the viewpoint of adhesion to the surface-cured layer, and more preferably 65 degrees. Not less than 85 degrees, most preferably 70 degrees
It is better to set the angle above 80 degrees.

Further, within a range that does not impair the effects of the present invention, other cross-linking agents such as methylolated or alkylolated urea type, acrylamide type, polyamide type resin, epoxy compound, isocyanate compound, aziridine compound, You may use together a silane coupling agent, a titanium coupling agent, etc.

The amount of the melamine-based cross-linking agent added is not particularly limited, but in order to bring out the effect of the present invention more remarkably, based on 100 parts by weight of the solid content used as the coating liquid,
Preferably 0.5-40 parts by weight, more preferably 1-3
0 parts by weight, most preferably 2 to 20 parts by weight. When the amount of the melamine-based cross-linking agent added is small, the moisture-resistant adhesiveness tends to be poor, and when it is excessively added, on the contrary, the adhesiveness tends to be lowered. That is, when the acrylic resin and the polyester resin are mixed and used, preferably 0.5 to 40 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the total solid content of the acrylic resin and the polyester resin,
Most preferably, it is 2 to 20 parts by weight.

Further, in the laminated film, other resins and modified products thereof, for example, polyester resins other than those according to the present invention, acrylic resins, etc., within the range where the effects of the present invention are not impaired.
A urethane resin, a polyolefin resin, a polycarbonate resin, an epoxy resin, a urea resin, a phenol resin, a vinyl chloride resin, a fluorine resin, a silicone resin, a rubber resin, or the like may be blended.

Further, in the laminated film, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, etc. are added within the range where the effect of the present invention is not impaired. Dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents and the like may be added.

In particular, in carrying out the present invention, it is more preferable that inorganic particles are added and blended in the coating liquid and biaxially stretched since the slipperiness is improved.

The inorganic particles to be added are typically:
Silica, colloidal silica, alumina, alumina sol,
Kaolin, talc, mica, calcium carbonate and the like can be used. The inorganic particles used have an average particle size of 0.0
It is preferably from 1 to 10 μm, more preferably from 0.05 to 5 μm, most preferably from 0.08 to 2 μm, and the compounding ratio to the solid content in the coating liquid is not particularly limited, but the weight ratio is 0. The amount is preferably 05 to 8 parts by weight, more preferably 0.1 to 3 parts by weight.

In carrying out the present invention, as a method of coating the water-based resin, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

The thickness of the laminated film is not particularly limited, but is usually preferably 0.01 to 5 μm, more preferably 0.0.
3-2 μm, most preferably 0.05 μm-0.5 μm
Range. If the thickness of the laminated film is too small, poor adhesion may occur.

In the present invention, the main constituent component of the easy-adhesion layer means that the component is 60% by weight or more in the easy-adhesion layer. However, in the present invention, it is desirable that the main constituent component is present in an amount of preferably 80% by weight or more, more preferably 90% by weight or more.

The laminated structure as described above can be realized by the following method, for example. That is, in the method for producing a polyester film, which comprises coating at least two kinds of water-based resin coating liquids having different solubility parameters such as acrylic resin and polyester resin, drying and then stretching at least uniaxially, Is obtained by drying the water-based resin under two or more different set drying conditions at the stage after coating and before stretching.

The laminated polyester film used for the surface-cured film of the present invention is not particularly limited as long as it can dry the aqueous resin coating liquid under the different set drying conditions of two or more steps described above. The following methods can be used. After drying the first step at a temperature lower than the glass transition point (Tg) of the base polyester resin, 2
It is possible to use a method in which the drying in the stage is performed at a temperature of Tg or higher, the temperature is brought to a temperature near Tg necessary for stretching (however, Tg or higher), and then stretching is performed. In particular, by setting the second-stage set drying temperature higher than the first-stage set drying temperature, the laminated structure of the present invention can be more remarkably exhibited. Further, the above-mentioned drying can be repeatedly used. Examples of the drying method used include a method using a radiation heater, a method of blowing heated hot air, and a combination of both.

At this time, it is preferable to increase the ambient temperature at 10 ° C./sec or more during the second stage drying temperature between the first stage and the second stage drying, and more preferable. Is 40 ° C / sec or more, most preferably 200 ° C
/ Sec or more.

In summary, in the present invention, the laminated film provided on the polyester film surface is made of two kinds of resins by using two kinds of resins having different solubility parameters and controlling the drying conditions when the laminated film is formed. It has been found that the resin of (1) has a phase separation structure, a resin having a small solubility parameter on the gas phase side and a resin having a large solubility parameter on the polyester film side, that is, a so-called phase separation structure. Further, they have found that a mixed phase of each phase exists at the interface between the surface layer and the intermediate layer of the laminated film.

In particular, when the above-mentioned mixed phase is present, the laminated film of the laminated polyester film has excellent adhesiveness with the coating material and at the same time excellent adhesiveness with the base film.
Further, the adhesiveness at the interface between both phases is improved.

In the present invention, before applying the coating liquid,
The surface of the base film is subjected to corona discharge treatment or the like, and the wetting tension of the surface is preferably 47 mN / m or more, more preferably 50 mN / m or more to improve the adhesion of the laminated film to the base film. Not only this, but also the above-mentioned phase separation can be made more remarkable.

In the surface-hardened film of the present invention, the surface-hardened layer (B) may be made of an acrylic type, urethane type, melamine type, organic silicate, silicone type, metal oxide or the like. In particular, in terms of hardness and durability, silicone type and acrylic type are preferable, and acrylic type is more preferable in view of curability, flexibility, and productivity, and actinic ray curing is most preferable. Acrylic type.

The actinic ray-curable acrylic system contains an acryl oligomer as an actinic ray polymerization component and a reactive diluent, and may further contain a photoinitiator, a photosensitizer, a modifier and the like.

As the acrylic oligomer, those having a reactive acrylic group bonded to an acrylic resin skeleton, polyester acryl, urethane acryl, epoxy acryl, polyether acryl and the like can be used, and melamine and isocyanuric acid can be used. Although a rigid skeleton such as an acrylic group may be used,
It is not limited to these.

The reactive diluent is a medium of the coating agent, that is, it has a group which itself functions as a solvent in the coating step and which itself reacts with a monofunctional or polyfunctional acrylic oligomer, The thing which becomes a copolymerization component of can be used.

In particular, in the case of crosslinking by ultraviolet rays, since the light energy is small, it is preferable to add a photopolymerization initiator and / or a sensitizer in order to promote conversion or initiation of light energy.

Specific examples of the above-mentioned acrylic oligomer, reactive diluent, photopolymerization initiator, sensitizer, crosslinking device, etc. are as follows:
Shinzo Yamashita, Tosuke Kaneko, "Handbook of Crosslinking Agents", published by Taiseisha in 1981, pages 267 to 275, 56.
Pages 2 to 593 can be referred to, but are not limited to these. In addition, as a commercially available multifunctional acrylic UV curable coating, Mitsubishi Rayon Co., Ltd.
Use products such as Fujikura Kasei Co., Ltd., Dainichi Seika Kogyo Co., Ltd., Dainippon Ink and Chemicals Co., Ltd., Toa Gosei Chemical Co., Ltd., Nitto Kasei Co., Ltd., Nippon Kayaku Co., Ltd. However, the present invention is not limited to these.

As the modifier for the surface hardened layer, a coating property improver, a defoaming agent,
Thickeners, antistatic agents, inorganic particles, organic particles, organic lubricants, organic polymers, dyes, pigments, stabilizers, etc. can be used to improve the properties of the surface hardened layer depending on the application. be able to.

In the present invention, when a surface-hardened layer is provided, an organic solvent is added within the range that does not impair the effects of the present invention for the purpose of improving workability during coating and controlling the coating film thickness. can do.

In the present invention, as the surface-hardened layer,
At least one kind of monomer having 3 or more (meth) acryloyloxy groups in one molecule and at least one kind of monomer having 1-2 ethylenically unsaturated double bonds in one molecule It is possible to use those composed of an actinic radiation-curable monomer composition mainly composed of an actinic radiation-curable monomer composition consisting of, in which case, hardness and curability are excellent, and further, abrasion resistance and flexibility. It is also preferable because it is excellent.

In the present invention, three or more (meth) acryloyloxy groups per molecule (however, in the present invention, the (meth) acryloyloxy groups are abbreviated as acryloyloxy groups and methacryloyloxy groups). A polyhydric alcohol having 3 or more alcoholic hydroxyl groups in one molecule is an esterified product of 3 or more (meth) acrylic acid. A compound can be used, for example, pentaerythritol tri (meth) acrylate,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) ) Acrylate and the like. These monomers can be used alone or in combination of two or more.

The proportion of the monomer having 3 or more (meth) acryloyloxy groups in one molecule is preferably 20 to 90% by weight, more preferably 30% by weight, based on the total amount of the polymerizable monomers. ~ 80% by weight, most preferably 30 ~
70% by weight.

The proportion of the monomers used is 20% by weight
When the amount is less than the above, the cured film is inferior in abrasion resistance, and when the amount exceeds 90% by weight, the shrinkage due to the polymerization is large, the cured film has a residual strain, or the flexibility of the cured film is small. It is not preferable because it decreases or curls greatly on the side of the cured film.

In the present invention, the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is not particularly limited as long as it is a usual radical polymerizable monomer. Can be used.

Examples of those having two ethylenically unsaturated double bonds in one molecule include (meth) acrylates of the following (a) to (f), and (a) alkylene glycol having 2 to 12 carbon atoms. (Meth) acrylic acid diesters:
Ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc., (B) Polyoxyalkylene glycol (meth) acrylate diesters: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and other (c) polyhydric alcohol (meth) acrylic acid diesters: pentaerythritol di (meth) acrylate ) Acrylate and the like, (meth) acrylic acid diesters of (d) ethylene oxide and propylene oxide adducts of hydrogenated bisphenol A or bisphenol A: 2,2′-bis (4-acryloxyethoxyphenyl) propane, 2,2 A terminal isocyanate group-containing compound obtained by previously reacting (e) a diisocyanate compound with two or more alcoholic hydroxyl group-containing compounds, such as'-bis (4-acryloxypropoxyphenyl) propane, further contains an alcoholic hydroxyl group-containing (meth ) Acrylic acid or a compound (f) having two or more epoxy groups in the molecule, such as urethane (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting acrylate Molecules obtained by reacting methacrylic acid Epoxy (meth) acrylates having two or more (meth) acryloyloxy groups therein can be preferably used in the present invention.

As those having one ethylenically unsaturated double bond in one molecule, methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n-, sec -, And t
-Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, polyethylene glycol Mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N-hydroxyethyl (meth)
Acrylamide, N-vinylpyrrolidone, N-vinyl-
3-Methylpyrrolidone, N-vinyl-5-methylpyrrolidone or the like can be used. These monomers are 1
You may use it in mixture of 2 or more types.

The proportion of the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is preferably 10 to 80% by weight, more preferably 20% by weight, based on the total amount of the monomers.
７０70% by weight.

80% by weight of the used monomer is used.
If it exceeds, it is difficult to obtain a cured coating having sufficient abrasion resistance, which is not preferable. Further, if the proportion used is less than 10% by weight, the flexibility of the cured coating is reduced and the adhesiveness with the laminated film provided on the base polyester film is reduced, which is not preferable.

As a method of curing the actinic ray-curable monomer composition used in the present invention, for example, a method of irradiating ultraviolet rays can be used. In this case, the actinic ray-curable monomer is used. It is preferable to add a photopolymerization initiator to the composition.

As the photopolymerization initiator, for example, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone,
4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Methylbenzoylformate, p-isopropyl-α-
Carbonyl compounds such as hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone, A sulfur compound such as 2-methylthioxanthone or a peroxide compound such as benzoyl peroxide or di-t-butyl peroxide can be used. These photopolymerization initiators may be used alone or in combination of two or more.

The amount of the photopolymerization initiator used is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the actinic ray curable monomer composition. When electron beam or gamma ray is used as the curing means, it is not always necessary to add a polymerization initiator.

The actinic radiation-curable monomer composition used in the present invention contains hydroquinone, hydroquinone monomethyl ether, and 2,5-t-, for the purpose of preventing thermal polymerization during production and dark reaction during storage. It is preferable to add a thermal polymerization inhibitor such as butyl hydroquinone. The addition amount, relative to the total weight of the actinic radiation curable monomer composition,
It is preferably 0.005 to 0.05% by weight.

The actinic radiation-curable monomer composition used contains various organic compounds within the range that does not impair the effects of the present invention for the purpose of improving workability during coating and controlling the coating film thickness. A solvent may be blended.

The organic solvent has a boiling point of 50 to 150 ° C.
Those are preferably used from the viewpoint of workability at the time of coating, drying properties before and after curing, for example, methanol, ethanol,
Examples include alcohol solvents such as isopropyl alcohol, acetic ester solvents such as methyl acetate, ethyl acetate and butyl acetate, ketone solvents such as acetone and methyl ethyl ketone, aromatic solvents such as toluene, and cyclic ether solvents such as dioxane. . These solvents may be used alone or in admixture of two or more.

The actinic radiation-curable monomer composition used may contain various additives such as antioxidants, light stabilizers, and ultraviolet absorbers within a range that does not impair the effects of the present invention. Agents, surfactants, leveling agents, antistatic agents and the like may be added.

Further, the actinic ray-curable monomer composition used is oxidizable within the range in which the effect of the present invention is not impaired for the purpose of reducing the brightness and clarity of the reflected image of the light source in the external environment. A matting agent such as silicon particles or an organic filler may be blended. Further, the surface of the surface-hardened layer may be provided with irregularities by, for example, an embossing method or a sand mat method.

As a method for applying the actinic ray-curable monomer composition, for example, brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, spin coating (spinner, whaler, etc.) and the like are used. You can Each of these methods has its characteristics, and the coating method can be appropriately selected and used depending on the required characteristics of the surface-cured film, the intended use, and the like.

In the practice of the present invention, active rays used include ultraviolet rays, electron rays, and radiations (α rays, β rays,
It is an electromagnetic wave that can polymerize acrylic vinyl groups such as gamma rays). Practically, ultraviolet rays are convenient and preferable,
As the ultraviolet ray source, for example, an ultraviolet fluorescent lamp, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a carbon arc lamp or the like can be used. The electron beam method is
The equipment is expensive and requires operation under an inert gas,
The surface-cured layer can be preferably used since it does not need to contain a photopolymerization initiator, a photosensitizer or the like.

The thickness of the surface-hardened layer is not particularly limited and may be appropriately selected depending on the intended use, but is usually preferably 0.5-.
It is 10 μm, more preferably 1 to 5 μm. If the thickness of the surface-hardened layer is less than 0.5 μm, the surface hardness is insufficient and scratches are likely to occur, and if it exceeds 10 μm, the hardened film tends to become brittle, and for example, when the surface-hardened film is bent. , The cured film is likely to be cracked.

Further, within the range where the effects of the present invention are not impaired, a printed layer of patterns, images, etc. may be provided on the surface of the surface hardened layer.

Next, the method for producing the surface-cured film of the present invention will be described by taking a polyethylene terephthalate (hereinafter abbreviated as "PET") film as an example of the substrate film, but the invention is not limited to this. Absent.

For example, the intrinsic viscosity is 0.5 to 0.8 dl / g
After vacuum-drying the PET pellets, the PET pellets are supplied to an extruder, melted at 260 to 300 ° C., extruded in a sheet form from a T-shaped die, and subjected to an electrostatic application casting method to obtain a surface temperature of 10
It is wound around a mirror-casting drum at -60 ° C and cooled and solidified to prepare an unstretched PET film. This unstretched film is stretched 2.5-5 times in the machine direction (the direction of film travel) between rolls heated to 70-100 ° C. At least one surface of this film is subjected to corona discharge treatment in air to have a wetting tension of 47 mN / m or more on the surface, and the coating liquid for forming the phase-separated structure of the present invention is applied to the treated surface. The coated film is held by a clip and guided to a drying zone, dried at a temperature of Tg or lower of the base polyester resin, then raised to Tg or higher, and dried again at a temperature near Tg, and continuously 70 to Stretching 2.5 to 5 times in the width direction in a heating zone of 150 ° C., then 160 to 2
Heat treatment is performed in a heating zone of 40 ° C. for 1 to 10 seconds to prepare a laminated PET film with crystal orientation completed. If necessary, a relaxation treatment of 3 to 12% may be performed during this heat treatment.

Biaxial stretching may be either longitudinal or transverse sequential stretching or simultaneous biaxial stretching, and after longitudinal or transverse stretching, it may be re-stretched in either longitudinal or transverse direction. Moreover, the thickness of the PET film is not particularly limited, but is 1 to 300.
μm is preferably used. The coating liquid used in this case is preferably an aqueous system from the viewpoint of environmental pollution and explosion proof.

The surface-cured film of the present invention has the above-mentioned laminated P
It can be obtained by further providing a surface-hardened layer on the laminated film of the ET film. That is, the surface hardened layer is
At least one monomer having 3 or more methacryloyloxy groups in one molecule and at least one monomer having 1-2 ethylenically unsaturated double bonds in one molecule
It can be obtained by applying a composition containing an actinic ray-curable monomer composition containing a seed as a main constituent on the laminated film, drying it if necessary, and then curing with actinic radiation.

In the above example, the base film on which the laminated film is provided also contains at least one selected from melamine-based cross-linking agents, oxazoline group-containing cross-linking agents, acrylic resins, polyester resins, and reaction products thereof. Can be made. In this case, the adhesiveness between the laminated film and the base film is improved, and the slipperiness of the laminated polyester film is improved. When a melamine-based cross-linking agent, an oxazoline group-containing cross-linking agent, an acrylic resin, a polyester resin, and a reaction product of these are contained, the addition amount is 5 ppm or more and less than 20% by weight, which indicates easy adhesion and easy adhesion. It is preferable in terms of lubricity. of course,
A melamine-based cross-linking agent, an oxazoline group-containing cross-linking agent, an acrylic resin, a polyester resin, and a reaction product thereof are coating compositions (including regenerated pellets of a laminated PET film according to the present invention) provided on a base film. Good.

The surface-cured film thus obtained has a high surface hardness, excellent abrasion resistance, and excellent durability of the surface-cured layer, and therefore can be used in a wide variety of applications. Specifically, for touch panels, displays attached to glass or metal plates, displays for electronic whiteboards and whiteboards, labels, stickers, OHP, cards, courier slips, image-receiving paper for printers, and various surface protective materials, For example, it can be used for a calculator or a cover of an instrument. Further, as the coated metal plate, it can be used for home electric appliances, office equipment, building materials, vehicles, steel furniture and the like.

[0108]

[Characteristic measuring method and effect evaluating method] The characteristic measuring method and effect evaluating method in the present invention are as follows. (1) Cross-sectional morphology of laminated film, phase-separated structure, and thickness of laminated film A cross-section of a laminated film is cut into ultrathin sections and stained by RuO ₄ staining, OsO ₄ staining, or double-staining of both, to obtain an ultrathin section method. , TEM (transmission electron microscope), and photographed. From the cross-sectional photograph, the phase separation state of the laminated film, the presence or absence thereof, the thickness of each phase, the thickness of the laminated film, etc. were confirmed and measured. In addition, the resin type was determined by the difference in dyeing density on the photograph. Further, a portion where both phases of the interface portion are intricate and cannot be determined as any of the phases is defined as the mixed phase.

The thickness of each phase was calculated from the thickness of the laminated film and the area ratio of the portion dyed with each resin.

Observation method-Device: Transmission electron microscope (H-7 manufactured by Hitachi, Ltd.)
100FA type) ・ Measurement conditions: Accelerating voltage 100 kV ・ Sample preparation: Frozen ultrathin section method

(2) Adhesiveness-1 100 crosscuts of 1 mm ² were put in the surface hardened layer,
Stick Nichiban cellophane tape on it,
After pressing it strongly with a finger, it was peeled off in the direction of 90 degrees, and evaluated according to the number of remaining four grades (◎: 100, ◯: 80 to 99,
Δ: 50 to 79, ×: 0 to 49). (◎), (○)
Has good adhesiveness and excellent durability.

(3) Adhesiveness-2 The surface-cured film was treated with 100 at 40 ° C. and 90% relative humidity.
After leaving it for a period of time, it was taken out, and after 5 minutes under normal conditions, the adhesiveness was evaluated by the same method as in the above (2).

(4) Pencil hardness In accordance with JIS-K5400, pencils of various hardnesses were applied to the surface-hardened layer at an angle of 90 degrees, scratched with a load of 1 kg, and the hardness of the pencil when scratched was displayed.

(5) Abrasion resistance The surface of the hardened layer was rubbed with steel wool # 0000,
The condition of scratches was evaluated according to the following criteria.

◯: Almost no scratch even if rubbed strongly Δ: Slightly scratched when rubbed considerably ×: Scratch even if weakly rubbed

[0116]

Next, the present invention will be described with reference to examples, but is not necessarily limited thereto.

Example 1 PET substantially free of particles (intrinsic viscosity 0.65 dl
/ G) After fully vacuum-drying the pellets, supply them to an extruder and melt them at 280 ° C, extrude them into a sheet from a T-shaped die, and use a static electricity casting method to make a mirror-casting drum with a surface temperature of 25 ° C. It was wrapped and cooled to solidify. This unstretched film was stretched 3.5 times in the longitudinal direction while passing through a group of heating rolls at 95 ° C. to obtain a uniaxially stretched film. One side of this film was subjected to corona discharge treatment in the air so that the wetting tension of the base film was 52 mN / m, and the treated surface was coated with an aqueous coating liquid. The coating thickness was set to 0.15 μm after completion of crystal orientation.

"Water-based coating liquid" A water-based coating liquid prepared by mixing acrylic resin / polyester resin / melamine-based crosslinking agent = 50/50/5 (weight ratio of solid content).

A water-based acrylic resin coating liquid obtained by copolymerizing methyl methacrylate / n-butyl acrylate / acrylic acid / acrylonitrile at a ratio of 40/55/2/3 (weight ratio) as an acrylic resin.

As a polyester resin, an aqueous polyester resin coating liquid comprising the following acid component and glycol component.

Acid component: terephthalic acid 30 mol%, isophthalic acid 15 mol%, 5-sodium sulfoisophthalic acid 5 mol% glycol component, ethylene glycol 30 mol%, 1,4-butanediol 20 mol%, melamine-based crosslinking agent As a methylol melamine coating liquid.

The coated uniaxially stretched film is held by a clip, guided to a preheating zone, and dried at an ambient temperature of 75 ° C.,
Once the temperature was raised to 125 ° C. and dried again at 95 ° C., it was continuously stretched 4.5 times in the width direction in a heating zone of 130 ° C., then heat-treated in a heating zone of 225 ° C. for 2 seconds to crystallize. A laminated PET film with completed orientation was prepared. At this time, the thickness of the base film was 188 μm.

On the laminated film of this film, a composition obtained by stirring and mixing 70 parts by weight of dipentaerythritol hexaacrylate, 30 parts by weight of N-vinylpyrrolidone and 4 parts by weight of 1-hydroxycyclohexyl phenyl ketone with a bar coater Was uniformly applied so that the coating thickness after curing would be 3 μm. After that, the light intensity is 20 mW / cm
Ultraviolet irradiation is performed for 50 seconds at ² and the total irradiation amount is 1000m
It was designated as J and cured to obtain a surface-cured film having a surface-cured layer on the laminated PET film via the laminated film. The results are shown in Table 1.

Example 2 A surface-cured film was obtained in the same manner as in Example 1 except that the thickness of the laminated film was 0.08 μm. The results are shown in Table 1.

Comparative Example 1 A surface-cured film was obtained in the same manner as in Example 1 except that the PET film not coated with the water-based coating liquid was prepared. The results are shown in Table 1.

Comparative Example 2 Surface hardening was carried out in the same manner as in Example 1 except that the aqueous PET coating composition of Example 1 was used as an acrylic resin / melamine type crosslinking agent = 100/5 (solid content weight ratio) to prepare a laminated PET film. I got a film. The results are shown in Table 1.

Comparative Example 3 Surface hardening was carried out in the same manner as in Example 1 except that the aqueous coating solution of Example 1 was used to prepare a laminated PET film using polyester resin / melamine type crosslinking agent = 100/5 (solid content weight ratio). I got a film. The results are shown in Table 1.

Example 3 Aqueous acrylic obtained by copolymerizing acrylic resin with methyl methacrylate / ethyl acrylate / acrylic acid / N-methylol acrylamide = 55/40/3/2 (weight ratio) with the aqueous coating liquid of Example 1. A surface-cured film was obtained in the same manner as in Example 1 except that the resin coating liquid was used. Table 1 shows the results
It was shown to.

Example 4 A surface-cured film was obtained in the same manner as in Example 1 except that the polyester resin was changed to the copolymerized polyester resin of the following components in the aqueous coating liquid of Example 1. The results are shown in Table 1.

Acid component: Terephthalic acid 23 mol% Isophthalic acid: 9 mol% Trimellitic acid: 15 mol% Sebacic acid: 3 mol% Glycol component: Ethylene glycol: 15 mol% Neopentyl glycol: 18 mol% 1,4-Butanediol: 17 mol% An ammonium salt type aqueous dispersion of a polyester resin comprising the above acid component and glycol component.

Examples 5 to 9 The mixing ratio (solid content weight ratio) of acrylic resin / polyester resin / melamine type crosslinking agent in the aqueous coating liquid of Example 4 is shown in Table 1.
A surface-cured film was obtained in the same manner as in Example 4 except that the changes were made as shown in the inside. The results are shown in Table 1.

Example 10 A surface-cured film was obtained in the same manner as in Example 1, except that the polyester resin was changed to the copolyester resin having the following components in the aqueous coating liquid of Example 1. The results are shown in Table 1.

Acid component 5 mole% terephthalic acid 35 mole% isophthalic acid 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid 5 mole% glycol component Ethylene glycol 20 mol% Diethylene glycol 20 mol% Neopentyl glycol 10 mol% An ammonium salt type aqueous dispersion of a polyester resin comprising the above acid component and glycol component.

Example 11 A surface-cured film was prepared in the same manner as in Example 4, except that the laminated PET film was prepared by using the aqueous coating liquid of Example 4 as acrylic resin / polyester resin = 50/50 (solid content weight ratio). Obtained. The results are shown in Table 1.

Example 12 In the aqueous coating liquid of Example 4, the following oxazoline group-containing crosslinking agent was used in place of the melamine type crosslinking agent, and acrylic resin / polyester resin / oxazoline group-containing crosslinking agent =
A surface-cured film was obtained in the same manner as in Example 4 except that the weight ratio was 60/40/10. Table 1 shows the results
It was shown to.

Oxazoline group-containing cross-linking agent Methyl methacrylate 60% by weight Butyl acrylate 20% by weight Styrene 5% by weight 2-Isopropenyl-2-oxazoline 15% by weight Water / propylene of the oxazoline group-containing resin composition copolymerized by the above composition Glycol monomethyl ether mixed solution

Example 13 In the aqueous coating liquid of Example 12, acrylic resin / polyester resin / oxazoline group-containing crosslinking agent = 60/40 /
A surface-cured film was obtained in the same manner as in Example 12 except that the weight ratio was 25 (solid content weight ratio). The results are shown in Table 1.

Example 14 In the aqueous coating liquid of Example 5, the oxazoline group-containing crosslinking agent used in Example 12 was further added, and acrylic resin / polyester resin / melamine type crosslinking agent / oxazoline group-containing crosslinking agent = 80 / A surface-cured film was obtained in the same manner as in Example 5 except that the weight ratio was 20/5/5 (solid content weight ratio). The results are shown in Table 1.

Example 15 A surface-cured film was obtained in the same manner as in Example 4, except that the substrate film was changed to polyethylene-2,6-naphthalate film. The results are shown in Table 2.

Example 16 In Example 4, instead of the PET pellets, PET in which titanium oxide was finely dispersed (containing 16% by weight) (intrinsic viscosity of 0.
A surface-cured film was obtained in the same manner as in Example 4 except that 62 dl / g) pellets were used. At this time, the laminated PE
The T film had an optical density of 1.5 and a whiteness of 85%. The results are shown in Table 2.

Example 17 Example 16 is repeated except that the polyester film is changed from the PET film to the PEN film in Example 16.
A surface-cured film was obtained in the same manner as in. The results are shown in Table 2.

Example 18 As a base film, except that the laminated PET film obtained in Example 4 was crushed and pelletized, and 30% by weight of polyethylene terephthalate was added and melt-extruded. A surface-cured film was obtained in the same manner. The same coating liquid as that used in Example 4 was used as the coating liquid. The results are shown in Table 2.

Example 19 On the laminated PET film of Example 4, 60 parts by weight of pentaerythritol triacrylate, 2,2'-bis (4
-Acryloxydiethoxyphenyl) propane 10 parts by weight, N-vinylpyrrolidone 30 parts by weight, 1-hydroxycyclohexylphenyl ketone 4 parts by weight, toluene 90
By weight, 70 parts by weight of butyl acetate and 70 parts by weight of isopropyl alcohol were stirred and mixed, and the composition obtained was uniformly applied using a bar coater so that the coating thickness after curing was 3 μm. A surface-cured film was obtained in the same manner as in Example 4 except that this was dried at 80 ° C. for 20 seconds and then irradiated with ultraviolet rays in a nitrogen atmosphere. The results are shown in Table 2.

Example 20 On the laminated PET film of Example 4, 70 parts by weight of dipentaerythritol hexaacrylate, 30 parts by weight of N-vinylpyrrolidone, 5 parts by weight of 1-hydroxycyclohexylphenylketone, silica powder (manufactured by Degussa) OK4
12, an average particle diameter of 4 μm) 3 parts by weight, butanol 70 parts by weight, and toluene 80 parts by weight were stirred and mixed to obtain a composition.
Using a bar coater, the coating was applied uniformly so that the coating thickness after curing was 3 μm. After drying this at 80 ° C. for 30 seconds, a surface-cured film was obtained in the same manner as in Example 4.
The results are shown in Table 2.

Comparative Example 4 Table 2 shows the results of the PET film of Example 4 in which neither the laminated film nor the surface-hardened layer was provided.

Comparative Example 5 The laminated PE obtained in Example 4 without the surface hardening layer.
The results of the T film are shown in Table 2.

[0147]

[Table 1]

[Table 2]

[0148]

EFFECTS OF THE INVENTION The surface-cured film of the present invention has a high surface hardness and excellent abrasion resistance because a surface-hardened layer is provided on a base polyester film via a specific laminated film, and at the same time, the surface-cured layer is excellent. It also has excellent durability. Therefore, it can be used in a wide range of applications such as a touch panel, a display attached to a glass or metal plate, a label, a sticker, an OHP, a card, a courier slip, and an image receiving paper for a printer.

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Claims (10)

[Claims] 1. A laminate in which a surface-hardened layer (B) is provided via a laminated film (A) provided on at least one surface of a polyester film, the laminated film (A) having a phase-separated structure in the thickness direction. A surface-hardened film having a mixed phase of each phase present at the phase separation interface. 2. The surface layer of the laminated film (A) is mainly composed of acrylic resin, and the intermediate layer between the surface layer of the laminated film and the polyester film is mainly composed of polyester resin. The surface-hardened film according to. 3. The surface-cured layer (B) comprises at least one monomer having 3 or more (meth) acryloyloxy groups in one molecule and 1 to 2 ethylenic monomers in one molecule. 3. An actinic radiation-cured product containing an actinic radiation-curable monomer composition composed of at least one monomer having a saturated double bond as a main constituent. Surface hardened film. 4. The laminated film (A) contains 0.5 to 40 parts by weight of a melamine-based cross-linking agent with respect to 100 parts by weight of a total of an acrylic resin and a polyester resin. The surface-cured film according to any one of 3 above. 5. The laminated film (A) contains 1 to 40 parts by weight of an oxazoline group-containing crosslinking agent with respect to 100 parts by weight of a total of acrylic resin and polyester resin. The surface-cured film according to any one of 1. 6. The surface hardening according to claim 1, wherein the polyester resin of the laminated film (A) is an aqueous polyester resin having a carboxylic acid and / or a salt thereof in a side chain. the film. 7. The surface-cured film according to claim 1, wherein the laminated film (A) has a contact angle with water of not less than 60 degrees and not more than 90 degrees. 8. The polyester film is a polyethylene terephthalate film or a polyethylene-2,6-naphthalate film.
The surface-cured film according to any one of 1. 9. When a laminated film (A) is provided, a coating agent for forming an easy-adhesion layer is applied to at least one side of a polyester film before completion of crystal orientation, followed by stretching in at least one direction and heat treatment to obtain crystal orientation. The surface-cured film according to any one of claims 1 to 8, which has been completed. 10. The polyester film is made of an acrylic resin, a polyester resin, a melamine-based cross-linking agent, or a composition containing at least one of reaction products thereof, according to any one of claims 1 to 9. The surface-hardened film according to.