JP2987854B2 - Plastic laminate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plastic laminate having excellent thermal dimensional stability, low specific gravity, high surface hardness, excellent wear resistance, and high whiteness. For more details, touch panel,
For decoration and display on glass or metal plates, for display of electronic whiteboards and whiteboards, etc., paper substitutes: guides, labels, stickers, courier slips, video printer receiving papers, barcode printer receiving papers The present invention relates to a plastic laminate used for a map, a map, and the like.

[Prior Art] It is well known that a white polyester film is obtained by adding a large amount of titanium dioxide or calcium carbonate to polyester. It is also well known that a white polyester film is obtained by adding polypropylene to polyester.

[Problems to be Solved by the Invention] However, a film obtained by adding a large amount of an inorganic substance such as titanium dioxide or calcium carbonate to a polyester,
Although whiteness can be imparted, the specific gravity cannot be reduced, and the film itself becomes hard and rough, which may cause a problem depending on the use. In addition, when polypropylene is added, the hardness of the film itself is somewhat relaxed as compared with the case where an inorganic substance is added, but not only the thermal dimensional stability is poor, but also the softness and flexibility compared with paper etc. Not only inferior but also inferior in whiteness.

Furthermore, the surface hardness of the film surface is low and the abrasion resistance is insufficient, so that the surface is easily damaged by contact, friction, scratching, etc. with other hard objects, and the damage generated on the surface reduces its commercial value. It can be significantly reduced or become unusable in a short time.

An object of the present invention is to solve the above problems and to provide a plastic laminate having excellent thermal dimensional stability, high whiteness, low specific gravity, high surface hardness and excellent friction resistance.

[Means for Solving the Problems] The present invention provides a film support (I) and a surface hardening layer (I
In the plastic laminate obtained by laminating I), the film support (I) is a polyester film having a heat shrinkage of less than 2% at 150 ° C. and a specific gravity of 0.95 or less, and an incompatible polymer is contained in the polyester film. Are dispersed and mixed,
And the shape factor of the incompatible polymer in the film is 1 to
The present invention relates to a plastic laminate characterized by No. 4.

The specific gravity of the polyester film constituting the film support (I) in the present invention is 0.95 or less, preferably 0.90 or less, more preferably 0.80 or less. If it is larger than 0.95, the film does not have a soft feeling and flexibility. Flexibility is necessary for clear transfer of an image even when the pressure of the thermal recording head is reduced when used as an image receiving paper for a video printer, for example.

The thermal dimensional stability is also important because the film does not deform even in a process to which heat is applied such as thermal transfer, printing, and drying. In particular, the heat shrinkage at 150 ° C. is often important.

The polyester in the present invention is a polymer obtained by polycondensation from a diol and a dicarboxylic acid, and examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, and sebacic acid. And a diol is
These are represented by ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol and the like. Specifically, for example, polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-p-oxybenzoate, poly-1,
4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate and the like can be mentioned. In the case of the present invention, polyethylene terephthalate and polyethylene naphthalate are particularly preferred.

Of course, these polyesters may be homopolyesters or copolyesters, and examples of the copolymerization component include diol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol, adipic acid, sebacic acid, and phthalic acid. And dicarboxylic acid components such as isophthalic acid, 2,6-naphthalenedicarboxylic acid and 5-sodium sulfoisophthalic acid.

Further, various known additives such as an antioxidant and an antistatic agent may be added to the polyester. Polyethylene terephthalate is preferred as the polyester used in the present invention. The polyethylene terephthalate film is excellent in water resistance, durability, chemical resistance and the like.

Incompatible polymers include poly-3-methylbutene-1,
Poly-4-methylpentene-1, polyvinyl-t-butane, 1,4-trans-poly-2,3-dimethylbutadiene,
Polyvinylcyclohexane, polystyrene, polymethylstyrene, polydimethylstyrene, polyfluorostyrene, poly-2-methyl-4-fluorostyrene, polyvinyl-t-butyl ether, cellulose triacetate, cellulose tripropionate, polyvinyl fluoride, polychlorotrifluoro It is preferably a polymer having a melting point of 200 ° C. or higher selected from ethylene and the like. In the case of the present invention, poly-4-methylpentene-1, cellulose triacetate and modified products thereof are particularly preferred in terms of price, heat stability, dispersibility with polyester, and the like. Of course, the melting point of the incompatible polymer is 200 ° C. or more, preferably 210 ° C. or more, and more preferably 220 ° C. or more.If the melting point is less than 200 ° C., the dispersion shape of the incompatible polymer in the polyester film becomes spherical. Instead, it often takes a layered flat shape, and the melting point of the incompatible polymer is preferably 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 260 ° C. or lower. This is because the incompatible polymer does not dissolve unless the temperature is below the melt extrusion temperature of the polyester.

The addition amount of the incompatible polymer is preferably 3 to
The content is 30% by weight, more preferably 5 to 20% by weight. If the addition amount is less than 3% by weight, not only is it difficult to obtain a polyester film of the present invention having a specific gravity of 0.95 or less, but also it is difficult to obtain a white polyester film having a whiteness of 80% or more.
On the other hand, if the amount of the incompatible polymer exceeds 30% by weight, not only the mechanical properties of the polyester film of the present invention become poor, but also the thermal dimensional stability becomes poor, and
This has a drawback that the heat shrinkage of such as is as large as 5% or more.

Next, the low specific gravity agent is a compound having an effect of reducing specific gravity by adding to polyester, and the effect is recognized only for a specific compound.

For example, polyalkylene glycols such as polyethylene glycol, methoxypolyethylene glycol, polytetramethylene glycol, and polypropylene glycol, ethylene oxide / propylene oxide copolymers, and sodium dodecylbenzene sulfonate;
Representative examples thereof include sodium alkylsulfonate, glycerin monostearate, and tetrabutylphosphonium paraaminobenzenesulfonate. In the case of the film of the present invention, polyethylene glycol is particularly preferred. By adding the low specific gravity agent, the specific gravity of the polyester film can be reduced by 0.1 g / cc or more.
Furthermore, the addition of this low specific gravity agent improves the whiteness of the polyester film, not only smoothing the surface, but also improving the cleavage resistance, and also has the effect of greatly improving the stretchability of the polyester. is there. The amount of the low specific gravity agent in the present invention is preferably 0.1 to 5% by weight,
More preferably, it is 0.5 to 3% by weight. If the addition amount is less than 0.1% by weight, the specific gravity of the polyester film does not become low, the film does not become a soft film and the specific gravity of the polyester film is 0.95 or less, preferably 0.90 or less, more preferably 0.85 or less. . Conversely, the additive is 5
If the amount exceeds 10% by weight, not only the effect of lowering the specific gravity is not recognized, but also the whiteness of the film decreases, and the b value becomes a large positive value.

Next, it is necessary that the immiscible polymer has a nearly spherical shape in the polyester film, that is, the shape factor is in the range of 1 to 4. Even if an incompatible polymer is added to the polyester film, the film properties obtained by the shape of the incompatible polymer, especially the correlation between the specific gravity of the film and the cushion rate, thermal dimensional stability, surface roughness, whiteness, etc. A big difference arises. In other words, when the shape of the immiscible polymer is close to spherical, not only can the specific gravity be reduced compared to the case where the incompatible polymer is dispersed in layers,
A film having high whiteness and a high cushioning ratio and good thermal dimensional stability can be obtained. It is predicted that the dispersion in a shape close to a spherical shape strongly depends on the viscosity, compatibility parameter, melting point, type of low specific gravity agent, addition amount, etc. of the incompatible polymer added to the polyester. It is very difficult. The shape close to a spherical shape means that the major axis and the minor axis of the incompatible polymer dispersed in the film are different from each other.
To 4, preferably 1 to 2.

Of course, if the thermal dimensional stability of the obtained film is not low, it cannot be used for applications that require heat, such as image receiving paper for printers. That is, the heat shrinkage of both the longitudinal and width axes at 150 ° C. must be less than 2%, preferably less than 1%. For this purpose, the polyester film must be subjected to a heat treatment at 200 ° C. or higher, preferably 220 ° C. or higher, and may be subjected to a relaxation treatment.

The whiteness of the polyester film is preferably 80% or more, more preferably 90% or more. Further, the color tone b value obtained by the color difference meter is -3 or less, preferably -4 or less, and-.
It is good to be 20 or more. As the b value is smaller, the apparent whiteness of the film is improved, giving a high-quality image.

The color tone changes depending on the addition of the above-mentioned incompatible polymer or low specific gravity agent, but if necessary, a fluorescent whitening agent may be added. As optical brighteners, trade name "Ubitek" OB,
MD (Ciba-Geigy), "OB-1" (Eastman) and the like.

In the polyester film of the present invention, fine particles such as calcium carbonate, amorphous zeolite particles, anatase type titanium dioxide, calcium phosphate, silica, kaolin, talc and clay may be used in combination. The amount of these additives is preferably 0.005 to 25 parts by weight based on 100 parts by weight of the polyester composition. Further, in addition to such fine particles, fine particles precipitated by the reaction between the catalyst residue and the phosphorus compound in the polyester polycondensation reaction system can also be included. As the precipitated fine particles, for example, those composed of calcium, lithium and phosphorus compounds, or those composed of calcium, magnesium and phosphorus compounds, and the like, the content of these particles in the polyester is based on 100 parts by weight of the polyester. It is preferably 0.05 to 1.0 part by weight.

Next, a method for producing the film support (I) of the present invention will be described, but the present invention is not limited to such an example.

Mix 4-methylpentene-1 polymer as an incompatible polymer, polyethylene glycol as a low specific gravity agent, and polyethylene terephthalate, and mix them thoroughly.
It is fed to the extruder A which has been dried and heated to a temperature of 270-300 ° C. If necessary, polyethylene terephthalate containing an inorganic additive such as TiO ₂ , SiO ₂ , CaCO ₃ is supplied to the extruder B by a conventional method, and the extruder B is placed in the three-layer die of the T die.
It may be laminated to three layers of B / A / B so that the polymer of the layer comes to both surface layers.

The melted sheet is tightly cooled and solidified by electrostatic force on a drum cooled to a drum surface temperature of 10 to 60 ° C., and the unstretched film is guided to a group of rolls heated to 80 to 120 ° C.
The film is longitudinally stretched 2.0 to 5.0 times in the longitudinal direction, and cooled with a group of rolls at 20 to 30 ° C.

Subsequently, the longitudinally stretched film is guided to a tenter while gripping both ends of the film with clips, and is horizontally stretched in a direction perpendicular to the longitudinal direction in an atmosphere heated to 90 to 140 ° C.

The stretching ratio is 2 to 5 times each in the vertical and horizontal directions, and the area ratio (longitudinal stretching ratio × lateral stretching ratio) is preferably 6 to 20 times. If the area magnification is less than 6 times, the whiteness of the obtained film becomes poor, and if it exceeds 20 times, the film tends to be broken at the time of stretching and the film forming property tends to be poor.

In order to impart the planarity and dimensional stability of the biaxially stretched film in this manner, the film is heat-set at 150 to 230 ° C. in a tenter, uniformly cooled, cooled to room temperature, and wound up. Obtain body (I).

The polyester film used in the present invention may have a corona discharge treatment, a urethane resin, an epoxy resin, etc. on the polyester film surface in contact with the surface hardness layer (II) in order to more firmly bond the polyester film layer and the surface hardness layer (II). An anchoring treatment may be performed using a known anchoring agent such as a resin, an acrylic resin, or a polyester resin.

In particular, those obtained by undercoating the reaction product of a vinyl copolymer containing a hydroxyl group and a partial ester group of phosphoric acid with a polyisocyanate compound (described in JP-B-58-35145), or an acrylic compound containing a hydrophilic group-containing polyester resin Undercoating with a composition consisting of a copolymer grafted with a polymer and a cross-linking agent improves the adhesion between the surface hardness layer (II) and the polyester film layer, and has durability such as wet heat resistance and boiling water resistance. Preferred as a film having excellent properties.

Further, a print layer such as a design and a picture is provided between the polyester film layer and the surface hardness layer (II) and / or the outermost layer of the surface hardness layer (II) within a range not to impair the object of the present invention. May be.

Examples of the surface hardening layer (II) in the present invention include acrylic, urethane, melamine, organic silicate, silicone, and metal oxides. Particularly, in terms of hardness and durability, silicone-based and acrylic-based are preferable,
Further, from the viewpoint of curability, flexibility and productivity, an acrylic resin, particularly an active ray-curable acrylic resin, is preferred.

The actinic radiation-curable acrylic resin contains an acrylic oligomer and a reactive diluent as actinic radiation polymerization components, and may further contain, if necessary, a photoinitiator, a photosensitizer, and a modifier. Acrylic oligomers include those in which reactive acrylic groups are bonded to an acrylic resin skeleton, polyester acryl, urethane acryl, epoxy acryl, polyether acryl, etc., and rigid skeletons such as melamine and isocyanuric acid To which an acrylic group is bonded, but is not limited thereto. The reactive diluent is a solvent for the coating process as a medium for the coating agent, and itself has a group that reacts with a monofunctional or polyfunctional acrylic oligomer. It is what becomes. Further, particularly in the case of crosslinking by ultraviolet rays, since the light energy is small, a photopolymerization initiator and a sensitizer are required for conversion of light energy and promotion of initiation. Specific examples of these acrylic oligomers, reactive diluents, photopolymerization initiators, sensitizers, crosslinking devices, etc. are described in Shinzo Yamashita and Tosuke Kaneko, "Handbook of Crosslinking Agents", Taiseisha, 1981, p. 267. No. 275
Pages, pages 562 to 593, but are not limited thereto. Mitsubishi Rayon Co., Ltd.
Products such as Fujikura Kasei Co., Dainichi Seika Kogyo Co., Ltd., Dainippon Ink and Chemicals Co., Ltd., Toa Gosei Chemical Co., Ltd. and Tonichi Kasei Co., Ltd. can be used, but not limited thereto.

Among them, in particular, at least one kind of the monomer (A) having three or more (meth) acryloyloxy groups in one molecule and one to two ethylenically unsaturated double bonds in one molecule. Surface hardening layer (II) composed of an actinic ray-curable monomer mixture containing at least one monomer (B) as a main component
However, not only hardness and curability, but also excellent wear resistance and flexibility are preferable.

In the present invention, three or more (meth) acryloyloxy groups in one molecule (here, the (meth) acryloyloxy group is an abbreviation of an acryloyloxy group and a methacryloyloxy group). In the following description, the term “△△△ (meta) □□□” is abbreviation of “△△△ □□□” and “△△△ meta □□□”. As A), 3 per molecule
Examples of the polyhydric alcohol having at least three alcoholic hydroxyl groups include compounds in which three or more hydroxyl groups are esterified (meth) acrylic acids.

Specific examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Examples thereof include dipentaerythritol hexa (meth) acrylate and trimethylolpropane tri (meth) acrylate.

These monomers (A) may be used alone or in combination of two or more.

The proportion of these monomers (A) used is preferably 20 to 90% by weight, more preferably 30 to 80% by weight, based on the total amount of the polymerizable monomers.

When the amount of the monomer (A) is less than 20% by weight, a cured film having a sufficient abrasion resistance cannot be obtained.
If the amount is more than the weight percentage, the shrinkage due to polymerization is large, and the cured film is undesirably distorted or the flexibility of the film is reduced.

As the monomer (B) having one or two ethylenically unsaturated double bonds in one molecule in the present invention, any ordinary monomer having radical polymerization activity can be used.

Examples of the compound having two ethylenically unsaturated double bonds in the molecule include the following (meth) acrylates (a) to (f).

(A) (meth) of alkylene glycol having 2 to 12 carbon atoms
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 ( (B) (b) (meth) acrylate diesters of polyoxyalkylene glycol: diethylene glycol (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di ( (C) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, etc. (c) (meth) acrylic acid diesters of polyhydric alcohols: pentaery (D) Bisphenol A or (meth) acrylic acid diesters of ethylene oxide and propylene oxide adducts of bisphenol A hydride: 2,2-bis (4-acryloxyethoxyphenyl) propane, 2, (E) a terminal isocyanate group-containing compound obtained by previously reacting a diisocyanate compound and two or more alcoholic hydroxyl group-containing compounds with an alcoholic hydroxyl group-containing compound (e.g., 2'-bis (4-acryloxypropoxyphenyl) propane); Urethane (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting acrylate: (f) acrylic acid or methacrylic compound in the compound having two or more epoxy groups in the molecule Obtained by reacting acid Epoxy having two or more (meth) acryloyloxy groups in a child (meth) acrylates: and the like.

Compounds having one ethylenically unsaturated double bond in the molecule include 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 and the like can be mentioned.

These monomers (B) may be used alone or in combination of two or more.

The use ratio of these monomers (B) is preferably from 10 to 80% by weight, more preferably from 20 to 70% by weight, based on the total amount of the monomers.

If the amount of the monomer (B) is more than 80% by weight, it is difficult to obtain a crosslinked cured film having sufficient abrasion resistance, which is not preferable. If the amount is less than 10% by weight,
It is not preferable because the flexibility of the film is reduced and the adhesion to the substrate is reduced.

One method of curing the active ray-curable composition in the present invention is a method of irradiating ultraviolet rays. In this case, it is desirable to add a photopolymerization initiator to the composition. Specific examples of the photopolymerization initiator include 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-hydroxyisobutylphenone, α-hydroxyisobutylphenone 2,2-dimethoxy-2-phenylacetophenone,
Carbonyl compounds such as 1-hydroxycyclohexylphenyl ketone, sulfur compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone, benzoyl peroxide, di-t-butyl peroxide and the like And the like. These photopolymerization initiators may be used alone or in combination of two or more. The use amount of the photopolymerization initiator is suitably 0.01 to 10 parts by weight based on 100 parts by weight of the polymerizable 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 ray-curable composition used in the present invention has a known thermal polymerization such as hydroquinone, hydroquinone monomethyl ether, 2,5-t-butylhydroquinone, etc. in order to prevent thermal polymerization during production and dark reaction during storage. It is desirable to add an inhibitor. The amount added is based on the total weight of the polymerizable compound.
0.005 to 0.05% by weight is preferred.

The actinic radiation-curable composition used in the present invention may contain an organic solvent within a range not to impair the purpose of the present invention, for the purpose of improving workability during coating and controlling the coating film thickness. it can.

As the organic solvent, those having a boiling point of about 50 ° C. to 150 ° C. are easy to use from the viewpoint of workability during coating and dryness before and after curing. Specific examples include methanol, ethanol,
Examples thereof include alcohol solvents such as isopropyl alcohol, acetate solvents such as methyl acetate and ethyl 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 as a mixture of two or more.

Various additives can be added to the actinic radiation-curable composition used in the present invention, if necessary, as long as the object of the present invention is not impaired. For example, antioxidants, light stabilizers,
Examples include stabilizers such as ultraviolet absorbers, surfactants, leveling agents, and antistatic agents.

The actinic radiation-curable composition used in the present invention has a glossiness such as silicon oxide particles and organic fillers within a range that does not impair the object of the present invention, for the purpose of reducing the brightness and clarity of the reflected image of the external light source. Erasers can be included. The surface of the actinic radiation-curable layer may be provided with irregularities by a generally known method such as an embossing method or a sand matting method.

Actinic radiation means electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation.
Ultraviolet light is convenient and preferred. The electron beam method is advantageous in that the apparatus is expensive and needs to be operated under an inert gas, but it is not necessary to include a photopolymerization initiator or a photosensitizer in the coating layer.

The thickness of the surface hardened layer (II) is 0.5μm or more and 10μ
m or less is desirable. It is more preferably 1 μm or more and 5 μm or less. When the thickness of the surface hardness layer is less than 0.5 μm, the surface hardness is insufficient and the surface is easily damaged, and when the thickness exceeds 10 μm, the cured film is easily brittle. Cracks are likely to occur in the film.

In addition, a print layer such as a design and a picture may be provided as the outermost layer of the surface hardening layer (II) as long as the object of the present invention is not impaired.

[Production Method] The plastic laminate of the present invention is produced by applying and hardening a surface hardness layer (II) on a flexible film support (I).

As the means for applying the actinic ray-curable composition of the present invention, commonly used coating methods such as brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, and spin coating (spinner, wooler, etc.) are used. Is easily applicable. Each method has its own characteristics, and the coating method is appropriately selected depending on the required performance of the laminate or the intended use.

Examples of a method of curing the active ray-curable composition of the present invention include a method of irradiating an active energy ray such as an ultraviolet ray, an electron beam or a gamma ray. Practically, the method using ultraviolet irradiation is simple and preferable. Examples of the ultraviolet light source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, and a carbon arc lamp.

[Use] The plastic laminate of the present invention thus obtained is used in a wide range of applications because of its low density, rich whiteness, and excellent surface hardness and wear resistance.

For details, touch panels, decorations and displays pasted on glass and metal plates, display of electronic whiteboards and whiteboards, paper substitutes such as cards, labels, stickers, courier slips, video printer receiving paper, barcodes It can also be used for various kinds of surface protective materials such as printer receiving paper, maps, etc., for example, calculators and instrument covers. In addition, home appliances, office equipment, building materials,
It can also be used for vehicles, steel furniture and the like. In particular, since it has excellent design properties and sharpness, it can be used for exterior members such as home electric appliances.

[Measurement of Physical Properties and Method of Evaluating Effect] Methods of evaluating physical properties and effects of the present invention are as follows.

(1) Surface roughness According to JIS B0601-1976, cutoff 0.25mm, measurement length
The center line average roughness Ra and the maximum roughness Rt were determined at 4 mm (μ
m).

(2) Average sphere equivalent diameter of voids A cross-section taken in the longitudinal direction of the film or in the vertical direction in the film forming process of the film in the film forming process is photographed at a magnification of 1000 to 5000 times with a scanning electron microscope. At least 100 or more voids in the specified thickness range were subjected to an image analyzer to determine the distribution of the diameter of a circle corresponding to the void area. The average diameter of the circle in this distribution is defined as the average equivalent sphere diameter of the void.

(3) Specific gravity 25 using a carbon tetrachloride-n-heptane density gradient tube.
The value at ° C was used.

(4) Overlay the optical density OD film to a thickness around 150 μm,
It is measured with an optical densitometer (TR927 manufactured by Magbes). A plot of the thickness and the optical density was made, and the optical density corresponding to a thickness of 150 μm was defined as the optical density converted to a thickness of 150 μm.

(5) Whiteness Based on JIS-L-1015, UV-260 manufactured by Shimadzu Corporation
When the reflectance at a wavelength of 450 nm is defined as B (%) and the reflectance at a wavelength of 550 nm is defined as G (%) when the magnesium oxide white plate is taken as 100%, the whiteness (%) is calculated by the following equation. Was.

Whiteness (%) = 4B-3G (6) Whiteness The surface color of the film was measured using a color difference meter manufactured by Nippon Denshoku Industries Co., Ltd.
The measurement was carried out at 80 and judged by the obtained L value, a value and b value.

(7) Shape Factor In the same manner as when determining the average diameter of voids, the shape of the immiscible polymer in the cross section of the film is applied to an image analyzer and expressed as a ratio of 100 average major axis / minor axis.

(8) Abrasion resistance The surface of the polyester film layer or the surface hardness layer was rubbed with steel wool # 0000, and the degree of scratching was evaluated according to the following criteria.

 S3: Hardly scratched even with strong friction.

 S2: Slightly scratches if rubbed hard.

 S1: Scratch even with weak friction.

(9) Pencil hardness According to JIS K5400, pencils of various hardness are applied to the polyester film layer surface at an angle of 90 °, scratched under a load of 1 kg, and indicated by the pencil hardness when scratches occur. did.

(10) Adhesiveness A cross cut (100 squares of 1 mm ² ) is placed in the cured layer, and a cellophane adhesive tape (cellophane tape CT-24 manufactured by Nichiban Co., Ltd.) is stuck thereon, and the cellophane tape is hand-applied. The degree of peeling after peeling was observed and evaluated according to the following criteria.

 A3: Good (peeling area less than 5%).

 A2: Slightly inferior (peeling area 5% or more and less than 20%).

 A1: Poor (peeling area 20% or more).

(11) Humidity and heat resistance After performing a moist heat test at 60 ° C and 90% RH using a thermo-hygrostat (Davaispec Co., Ltd. Platinous Humider PH-1G), observe appearance changes such as cracks. And
Further, the cross cut test (10) was performed in the same manner.

(12) Boiling Water Resistance The laminate was immersed in boiling water for 1 hour, observed for abnormal appearance such as cracks, and then subjected to the same cross-cut test as (10).

(13) Glossiness Using a glossiness measurement device (Suga Test Instruments Co., Ltd. Digital Variable Glossmeter UGV-4D) in accordance with JIS Z-8741, incident angle 60
The surface glossiness of ゜ was measured.

[Examples] The present invention will be described based on examples. However, the present invention is not limited to the following examples. In the examples, parts and% mean parts by weight and% by weight, respectively.

Example 1 Polyethylene terephthalate (intrinsic viscosity [η] = 0 =
65) at 88% by weight, poly-4-methylpentene-1 (Mitsui Petrochemical Co., Ltd. TPX-D820) at 10% by weight and a molecular weight of 4000.
The raw material obtained by mixing 2% by weight of the polyethylene glycol was supplied to an extruder A, melted at 285 ° C. by a conventional method, and introduced into a central layer of a T-die three-layer composite die.

On the other hand, the polyethylene terephthalate 90% by weight,
A raw material to which 10% by weight of calcium carbonate (average particle size 0.8 μm) was added and 0.01% by weight of a fluorescent brightener “OB-1” was added was supplied to an extruder B, and melted at 285 ° C. by a conventional method. T die 3
The laminated sheet was laminated on both surface layers of the die, and the melt sheet was tightly cooled and solidified by an electrostatic charge method on a cooling drum maintained at a surface temperature of 25 ° C. Subsequently, using a group of rolls heated to 98 ° C. in the longitudinal direction of the cast sheet according to a conventional method.
It was stretched 5 times and cooled to 25 ° C. Furthermore, the stretched film is guided to a numeric keypad, and in the width direction in an atmosphere heated to 125 ° C.
The film was stretched 3.2 times and heat-set at 225 ° C. to obtain a film having a thickness of 100 μm. The thickness of the film is,
The central layer had a configuration of 90 μm.

The physical properties of the obtained film were as follows: specific gravity 0.77, whiteness 105
%, Color tone L value 93, a value -1.0, b value -4.3, optical density 1.
1.Thermal shrinkage is 0.7% in longitudinal direction, 0.2% in width direction, surface roughness R
a0.21 μm, Rt1.85, dispersion shape is spherical, shape factor is 1.0, thermal dimensional stability is excellent, and whiteness is high and low specific gravity polyester film.

Next, 70 parts by weight of dipentaerythritol hexaacrylate and N-vinylpyrrolidone 30
The composition obtained by stirring and mixing 4 parts by weight of 1 part by weight and 1 part by weight of 1-hydroxycyclohexylphenyl ketone (“IRUGACURE” 184 from Ciba Geigy) was uniformly applied using a bar coater so that the film thickness after curing was 3 μm. . This was cured at a speed of 3 m / min under a high-pressure mercury lamp (manufactured by Toshiba) having an intensity of 80 W / cm and set at a height of 12 cm from the coated surface to obtain a laminate.

The surface of this laminate is smooth, abrasion resistance is S3, pencil hardness is 3
H, the cellophane tape peeling test by cross cut was rank A3.

Example 2 A 100 μm film was obtained in exactly the same manner as in Example 1 except that the amount of the low specific gravity agent polyethylene glycol (PEG) used in Example 1 was changed to 0.8 part by weight.

The physical properties of the obtained film are specific gravity 0.82, heat shrinkage is 0.9% in longitudinal direction, 0.2% in width direction, color tone b value -4.1, shape factor
A film with a low specific gravity of 1.2 and excellent thermal dimensional stability.

The actinic ray-curable coating composition used in Example 1 was applied on this support film and cured in the same manner to obtain a laminate.

The surface of this laminate is smooth, abrasion resistance is S3, pencil hardness is 3
H, the cellophane tape peeling test by cross cut was rank A3.

Example 3 Polyethylene terephthalate (intrinsic viscosity [η] = 0.6
5) Raw material obtained by mixing 88% by weight of poly (4-methylpentene-1) (10% by weight of Mitsui Petrochemical Co., Ltd. TPX-D820) and 2% by weight of polyethylene glycol having a molecular weight of 4000 is supplied to the extruder A. And melted at 285 ° C according to a conventional method.
It was introduced into the central layer of the layer composite die.

On the other hand, the polyethylene terephthalate 90% by weight,
A raw material to which 10% by weight of calcium carbonate (average particle size 0.8 μm) was added and 0.01% by weight of a fluorescent brightener “OB-1” was added was supplied to an extruder B, and melted at 285 ° C. by a conventional method. T die 3
The laminated sheet was laminated on both surface layers of the die, and the melt sheet was tightly cooled and solidified by an electrostatic charge method on a cooling drum maintained at a surface temperature of 25 ° C. Subsequently, using a group of rolls heated to 98 ° C. in the longitudinal direction of the cast sheet according to a conventional method.
It was stretched 5 times and cooled to 25 ° C.

Next, "Pesresin" 604G (Takamatsu Oil & Fat Co., Ltd.) was obtained as a water-dispersible polyester copolymer grafted with acrylic.
Melamine-based cross-linking agent "Nikarac" MW-12LF (manufactured by Sanwa Chemical Co., Ltd.)
4 parts by weight based on 100 parts by weight of resin solids, and as a lubricant 0.5 parts by weight of silica gel "Cataloid" (manufactured by Kasei Kasei Kogyo Co., Ltd.) having an average particle diameter of 0.10 μm based on 100 parts by weight of resin solids A coating agent having a concentration of 3.0% by weight was applied to one surface of the uniaxially stretched film by a metalling bar method, and then the coated layer was dried at 100 ° C. in a horizontal direction at 3.5%.
The film was double-stretched and heat-treated at 220 ° C. for 5 seconds while relaxing 3% in the transverse direction to obtain a laminated polyester film having a thickness of 100 μm on which a modified layer of 0.1 μm was laminated.

60 parts of pentaerythritol triacrylate, 10 parts of 2,2'-bis (4-acryloxydiethoxyphenyl) propane, 10 parts of N-vinylpyrrolidone A composition obtained by stirring and mixing 30 parts, 1 part of 1-hydroxycyclohexyl phenyl ketone, 90 parts of toluene, 70 parts of butyl acetate, and 70 parts of isopropyl alcohol was cured using a bar coater to a thickness of 3 μm. Was applied uniformly. This was dried at 80 ° C. for 18 seconds, and cured at a speed of 5 m / min under a high-pressure mercury lamp having an intensity of 80 W / cm set at a height of 12 cm from the application surface under a N ₂ atmosphere to obtain a laminate. .

The surface of this laminate is smooth, abrasion resistance is S3, pencil hardness is 3
H, the cellophane tape peeling test by cross cut was rank A3, the moisture and heat resistance was rank A3, and the boiling water resistance was rank A3.

Example 4 70 parts by weight of dipentaerythritol hexaacrylate and 30 parts by weight of N-vinylpyrrolidone were coated on the undercoated surface using a support film undercoated with a hydrophilic group-containing polyester resin grafted with acryl in the same manner as in Example 3. Department,
5 parts by weight of 1-hydroxycyclohexyl phenyl ketone, silica powder (manufactured by Degussa Corporation, OK-412, average particle size 4)
μm) A composition obtained by stirring and mixing 3 parts by weight, 70 parts by weight of butanol, and 80 parts by weight of toluene was uniformly applied using a bar coater so that the film thickness after curing became 3 μm. After drying at 80 ° C. for 30 seconds, 80 was set at a height of 12 cm from the application surface.
The laminate was passed under a high-pressure mercury lamp having an intensity of W / cm at a speed of 3 m / min. The resulting laminate has abrasion resistance S
3. Pencil hardness 3H, cellophane tape peeling test rank A3 by cross-cut, moisture and heat resistance rank A3, boiling water resistance rank A3, surface glossiness 40.

Comparative Example 1 The abrasion resistance of only the support film obtained in Example 1 was
The entire surface is scratched by S1, and the surface hardness is low.

As described above, when the surface hardening layer is not provided, a plastic laminate excellent in wear resistance and surface hardness cannot be obtained.

[Effects of the present invention] The present invention provides a film support (I) having a heat shrinkage and a specific gravity within a specific range, and a shape of an incompatible polymer dispersed in polyester having a shape close to a sphere. The provision of the surface hardness layer (II) has the following effects.

1. Despite its specific gravity as low as 0.95 or less, it has excellent thermal dimensional stability and obtains a film with high whiteness.

2. High whiteness and low color tone b value can be obtained, giving a high quality image.

3. A laminate with high whiteness and excellent surface hardness and wear resistance can be obtained.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B32B 1/00-35/00 C08J 9/00

Claims (6)

(57) [Claims] A film support (1) and a surface hardening layer (I)
In the plastic laminate obtained by laminating I), the film support (I) is a polyester film having a heat shrinkage of less than 2% at 150 ° C. and a specific gravity of 0.95 or less, and an incompatible polymer is contained in the polyester film. Are dispersed and mixed,
And the shape factor of the incompatible polymer in the film is 1 to
4. A plastic laminate, characterized in that: 2. A monomer (A) wherein the surface hardening layer (II) has three or more (meth) acryloyloxy groups in one molecule.
And an at least one monomer (B) having one or two ethylenically unsaturated double bonds in one molecule. The plastic laminate according to claim (1). 3. The plastic laminate according to claim 1, wherein the color tone b value of the film support (I) determined by a color difference meter is -3 or less. 4. The film support (I) wherein the incompatible polymer is a methylbutene polymer, a methylpentene polymer,
The plastic laminate according to any one of claims 1 to 3, wherein the polymer is a polymer having a melting point of 200 ° C or higher selected from a styrene-based polymer, a fluorine-based polymer, cellulose acetate, and a cellulose propionate polymer. body. 5. The plastic laminate according to claim 1, wherein the film support (I) is obtained by adding a low specific gravity agent to polyester. 6. The method according to claim 1, wherein said low specific gravity agent in the film support (I) is polyalkylene glycol, ethylene oxide /
The plastic laminate according to claim 5, which is selected from a propylene oxide copolymer, an alkylbenzene sulfonate, an alkyl sulfonate, and a modified product thereof.