JP3709937B2 - Multilayer film for sublimation type thermal transfer material - Google Patents

Description

【表２】

【００８６】
【発明の効果】
熱可塑性樹脂Ａと無機粒子とを主成分とするフィルムＡを、熱可塑性樹脂Ｂを主成分とするフィルムＢの少なくとも片面に積層し、前記フィルムＡの厚さが０．００５〜５μｍ、該フィルムＡ中に含有される前記粒子の体積平均径が積層厚さの０．１〜３倍、該粒子のフィルムＡ中の含有量が０．１〜５０重量％である二軸配向熱可塑性樹脂フィルムであって、該積層フィルムの少なくとも片面にアクリル樹脂とポリエステル樹脂を主たる構成成分とする層（Ｃ層）が積層されてなる積層フィルムであって、易接着性、印刷特性に優れ、昇華型感熱転写材に好ましく用いられる。[0001]
[Industrial application fields]
The present inventionAs a sublimation thermal transfer materialThe present invention relates to a suitable laminated film.
[0002]
[Prior art]
Polyesters, particularly polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate or poly-1,4-cyclohexanedimethylene terephthalate and polyesters based on these as thermoplastic resins have excellent physical and chemical properties. It is widely used as a fiber, film or sheet, and further as a molded product thereof.
[0003]
In particular, polyester film has excellent properties such as heat resistance, chemical resistance, and mechanical properties. Therefore, general industrial materials such as magnetic recording materials, electrical insulating materials, photosensitive materials, heat sensitive materials, drafting materials, and photographic materials. It is used as a base film for many applications such as packaging materials.
[0004]
In these applications, the polyester film is not used alone, but various coatings on the film surface, such as magnetic paint, UV ink, chemical mat paint, diazo photosensitive paint, sublimation ink, gelatin composition, heat seal application A composition or the like is applied or printed. In particular, a film used for a thermal transfer material, particularly a sublimation type thermal transfer material, requires the following functions on each film surface. On the side where the sublimation ink layer is provided, easy adhesion between the sublimation ink and the substrate film is required. On the opposite side of the stick prevention layer, the friction with the thermal head during transfer is reduced, and the thermal conductivity is improved, that is, the contact area with the thermal head is increased by reducing coarse protrusions. There is also a strong demand for improvement.
[0005]
In general, biaxially oriented polyester films have poor adhesion due to the highly crystallized surface, and various coatings such as magnetic paint, UV ink, chemical mat paint, diazo photosensitive paint, sublimation ink, Even if a gelatin composition, a heat seal imparting composition or the like is applied or printed, it does not adhere at all. For this reason, when applying or printing, physical treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment in various gas atmospheres on the film surface in order to improve the adhesion to the coating. Attempts have been made to perform chemical treatment with alkali, trichloroacetic acid, amine, phenols, etc., or a treatment method using these in combination, but none of them has sufficient adhesion. In addition, easy adhesion by the primer treatment of the film surface is widely performed due to advantages such as processing process, work safety and maintaining high quality of film processed products, and at the same time primer processing ( A method of applying a water-based paint such as a polyester resin, an acrylic resin, or a urethane resin and then stretching to form a coating film layer is considered promising in terms of process simplification and manufacturing cost, and is being actively implemented.
[0006]
In addition, when used as a thermal transfer material, a fluorine-based or silicone-based easy-slip layer is provided to reduce friction with the thermal head during transfer. The amount of heat applied to is increasing. For this reason, it is necessary to increase the thickness of the stick prevention layer in order to prevent the stick phenomenon in which the thermal head and the base film are fused, but this is counterproductive because it leads to insufficient heat during printing. For this reason, methods of increasing the protrusions of the base film or giving coarse protrusions have been taken in order to provide easy slipping with a conventional thickness.
[0007]
[Problems to be solved by the invention]
However, the above-described conventional technology has the following problems.
[0008]
For example, in order to give easy adhesion with a coating, a polyester resin laminated or applied to a polyester film has very good adhesion to a base film, but on the other hand has good adhesion to the coating. There is a tendency to be inferior. In particular, when sublimation-type ink is used as the coating, the easy-adhesion layer is easily dyed by the dye in the binder, so that the original color density and transferability are insufficient when transferred to the image receiving paper. And so on. In addition, a laminate or application of an acrylic resin on a polyester film has the disadvantage that the adhesion to the base film is inferior, although the problems caused by the adhesion with the polyester resin coating described above are cleared. is there.
[0009]
On the other hand, in order to prevent sticking, a method of increasing the protrusion of the base film or giving a rough protrusion is used, but this method causes a reduction in the contact area with the thermal head, and the amount of heat during printing It leads to shortage and deteriorates printing characteristics. For these reasons, there is a demand for a substrate film having uniform protrusions without coarse protrusions and having excellent printing characteristics.
[0010]
  The present invention eliminates these drawbacks, and is a biaxially oriented thermoplastic resin film having a laminated structure of a thermoplastic resin A and a thermoplastic resin B, the thermoplastic resin A having a specific size.inorganicBy adopting a biaxially oriented thermoplastic resin film that improves the film surface characteristics on the thermoplastic resin A side by concentrating and containing the particles, the film surface is efficiently, densely and highly Uniform protrusions can be formed, and by making uniform protrusions without coarse protrusions, not only the slipperiness of the base film is good, but also in thermal transfer material applications, the thermal conductivity during transfer is improved. By increasing it, the printing characteristics are improved. Furthermore, another object of the present invention is to provide a laminated film suitable for a sublimation type heat-sensitive transfer material having excellent adhesion to a coating by providing a layer (C layer) mainly composed of an acrylic resin and a polyester resin.
[0011]
  The present invention relates to a thermoplastic resin A andinorganicA film A mainly composed of particles is laminated on at least one surface of a film B mainly composed of a thermoplastic resin B, and the A of the film is contained in the film A having a thickness of 0.005 to 5 μm. Of the particlesVolume averageThe diameter is 0.1 to the thickness of the film A3A biaxially oriented thermoplastic resin laminated film in which the content of the particles in the film A is 0.05 to 50% by weight, the main constituent components being an acrylic resin and a polyester resin on at least one side of the laminated film; A layered film for a sublimation type thermal transfer material formed with a layer (C layer) to be formed is used as the main point.
[0012]
The thermoplastic resin A in the present invention is not particularly limited to polyesters, polyolefins, polyamides, polyphenylene sulfides, etc., but particularly polyesters, among them ethylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, ethylene-α, β- When at least one component selected from bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate or the like is used as a main component, high density and uniform protrusions are formed on the film surface. Is preferable because it becomes even better. Further, when the thermoplastic resin constituting the present invention is crystalline, the thermoplastic resin A is extremely desirable because it easily forms a target protrusion on the layer surface. The crystallinity here means that it is not so-called amorphous. Quantitatively, the cold crystallization temperature Tcc in the crystallization parameter is detected and the crystallization parameter ΔTcg is 150 ° C. or less. is there. Furthermore, when the heat of fusion (melting enthalpy change) measured by a differential scanning calorimeter exhibits a crystallinity of 7.5 cal / g or more, it is extremely desirable because the surface projection forming ability of the thermoplastic resin A layer is excellent. Further, in the case of a polyester having ethylene terephthalate as a main constituent component, the surface protrusion formation characteristics of the thermoplastic resin A layer are further improved, which is particularly preferable. In addition, within the range which does not inhibit this invention, 2 or more types of thermoplastic resins may be mixed, a copolymer polymer may be used, antioxidant, a heat stabilizer, a lubricant, and an ultraviolet absorber. The organic additive such as may be added to such an extent that it is usually added.
[0013]
  In the thermoplastic resin A of the present inventioninorganicThe shape of the particles is not particularly limited, but the particle size ratio in the film (inorganicThe major axis / minor axis of the particles is 1.0 to 1.3inorganicParticles, especially sphericalinorganicIn the case of particles, film surface protrusions having a uniform height are easily formed, which is desirable.
[0014]
  Further, in the thermoplastic resin A of the present inventioninorganicThe particles are particularly desirable when the single particle index in the film is 0.7 or more, preferably 0.9 or more, because it is easy to form protrusions of uniform height at high density.
[0015]
  In the thermoplastic resin A of the present inventioninorganicThe type of particles is not particularly limited, but alumina silicate, silica in which primary particles are aggregated, and internally precipitated particles are not preferable in order to satisfy the above preferable particle characteristics. preferableinorganicAs a particle, a substantially spherical silica particle due to colloidal silicaChildEtc.TheIn the case of spherical silica derived from colloidal silica, substantially spherical silica produced by an alkoxide method and having a low sodium content is desirable. However, otherinorganicParticles such as calcium carbonate, titanium dioxide, alumina, etc.Volume averageIt can be fully used by appropriate control of the diameter.
[0016]
The thickness of the film layer mainly composed of the thermoplastic resin A of the present invention is required to be 0.005 to 5 μm, preferably 0.01 to 1 μm, more preferably 0.03 to 0.5 μm. If the film thickness is smaller than the above range, durability as a laminated film layer cannot be ensured.inorganicDue to the relationship with the particles, it becomes difficult to form surface protrusions of appropriate height with high density.
[0017]
  Contained in the thermoplastic resin A filminorganicThe size of the particles is determined in the laminated film containing the particles.Volume averageThe diameter is in the range of 0.1 to 10 times, preferably 0.5 to 5 times, more preferably 1.1 to 3 times the thickness of the laminated film.Volume averageWhen the diameter / film thickness ratio is smaller than the above range, the variation of the film surface protrusion formed becomes large, the slipperiness decreases, and the handling property of the film decreases. On the contrary, even if it is large, it is not preferable because the projection height becomes nonuniform and the particle concentration ratio on the film surface described later tends to be reduced, resulting in poor printing characteristics.
[0018]
  Further, in the thermoplastic resin AinorganicIn a film of particlesVolume averageWhen the diameter (diameter) is in the range of 0.005 to 3 μm, and preferably in the range of 0.02 to 0.45 μm, the printing characteristics are further improved, which is desirable.
[0019]
  And like thisinorganicThe particles are contained in a film of the thermoplastic resin A in an amount of 0.05 to 50% by weight, preferably 0.075 to 10% by weight, more preferably 0.1 to 5% by weight. If it is smaller than this, the film surface protrusion formation density will be too low, and sufficient slipperiness will not be obtained.inorganicSince the ratio of particles becomes too high and the laminated film layer itself becomes too brittle, it is not preferable.
[0020]
  Further, the average height of the surface protrusions of the laminated film layer of the thermoplastic resin A formed by the particles is preferablyinorganicParticulateVolume average1 / 3.5 or more of the diameter. Surface protrusions with such an average height are contained in the laminated film thickness from the aforementioned range.inorganicParticulateVolume averageIt is obtained by appropriately selecting and setting the diameter.
[0021]
  That is, in the laminated film layer of the thermoplastic resin A in the present invention, the vicinity of the film thickness or larger than that.Volume averageDiameterinorganicContains particles. In other words, the ultrathin laminated film has a thickness near or larger than the film thickness.Volume averageSmall diameterinorganicContains particles. Therefore, with respect to the entire biaxially oriented thermoplastic resin film, the thickness direction is substantially concentrated only on the laminated film layer.inorganicParticles can be distributed. As a result, the density of particles that can be placed in the laminated film can be easily increased, and the density of protrusions on the film surface formed by the particles can be easily increased. Also,inorganicBy including the particles in the laminated film, the position of the particles is regulated in the thickness direction with respect to the entire biaxially oriented thermoplastic resin film.Volume averageSince the diameter has the relationship as described above, the height of the surface protrusion formed by the particles is extremely uniform. By forming the surface protrusions with a high density and a uniform height, the printing characteristics are greatly enhanced by the smoothness as well as the slipperiness.
[0022]
The thermoplastic resin A andinorganicA film mainly composed of particlesheatIt is laminated on a film mainly composed of the plastic resin B.
[0023]
The thermoplastic resin B is the same as the thermoplastic resin A described above, and the thermoplastic resin B and the thermoplastic resin A may be the same type or different. The film layer of the thermoplastic resin A is laminated on one side or both sides of the film layer made of the thermoplastic resin B. That is, this is a case where the laminated structure is A / B, A / B / A (here, the types of the thermoplastic resins of A and B may be the same or different).
[0024]
As the thermoplastic resin B, a crystalline polymer is desirable, and in particular, when the crystallization parameter ΔTcg is in the range of 20 to 100 ° C., for example, the durability of the entire base film as a heat-sensitive transfer material becomes even better. So desirable. Specific examples include polyester, polyamide, polyphenylene sulfide, and polyolefin. Polyester is particularly desirable because the durability of the entire film is further improved. The polyester is at least one structural unit selected from ethylene terephthalate, ethylene-2,6-naphthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate, and the like. The main component is preferably used as a film for a thermal transfer material. However, other components may be copolymerized within a range that does not inhibit the present invention and within a range that does not impair desirable crystallinity, and preferably within 5 mol%.
[0025]
Further, the thermoplastic resin B of the present invention may be blended with other kinds of polymers within the range not impairing the object of the present invention, and may be an antioxidant, a heat stabilizer, a lubricant, an ultraviolet absorber, etc. It may be added to such an extent that organic additives are usually added.
[0026]
The film containing the thermoplastic resin B as a main component is not particularly required to contain particles, but particles having an average particle diameter of 0.007 to 2 μm, particularly 0.02 to 0.45 μm are preferably 0.001 to 0.001. The content of 0.2% by weight, particularly 0.005 to 0.15% by weight, and further 0.005 to 0.12% by weight is preferable from the viewpoint of, for example, improving the film winding shape. It is desirable to use particles that are desirably used for the thermoplastic resin A as the kind of particles to be contained. The types and sizes of the particles contained in the thermoplastic resins A and B may be the same or different.
[0027]
  As aboveinorganicThe thermoplastic resin A containing particles and the thermoplastic resin B are laminated by coextrusion and formed into a sheet, and then biaxially stretched to obtain a biaxially oriented thermoplastic resin film. Lamination by coextrusion in the present invention isinorganicIt means that the thermoplastic resin A containing particles and the thermoplastic resin B are extruded by different extruders and are laminated before discharging the laminated sheet from the die. This lamination may be performed in a die (for example, a manifold) for molding and discharging into a sheet shape. However, since the laminated film layer is extremely thin as described above, it is carried out in a polymer tube before being introduced into the die. It is preferable. In particular, it is particularly preferable that the laminated portion in the polymer tube is formed in a rectangular shape because it can be uniformly laminated in the width direction. The molten polymer laminated in the polymer tube rectangular laminated portion is widened to a predetermined width in the sheet width direction by a manifold in the die, discharged into a sheet form from the die, and then stretched biaxially. Therefore, even if the laminated film after biaxial orientation is extremely thin,inorganicSince the particle-containing thermoplastic polymer is laminated with a considerable thickness, it can be laminated easily and accurately.
[0028]
  Moreover, in the biaxially oriented thermoplastic resin film comprising the thermoplastic resin A and the thermoplastic resin B,inorganicOf the surface layer on the side of the laminated film containing particlesinorganicThe particle concentration ratio by particles is preferably 0.1 or less. This surface layer particle concentration ratio forms film surface protrusions as shown in the measurement method described later.inorganicIt shows how the particles are covered with a thin film of thermoplastic resin A on the film surface,inorganicThe higher the degree to which the particles are substantially directly exposed to the film surface, the higher the surface particle concentration ratio, and the higher the degree to which surface protrusions are formed but covered with the thin film of the thermoplastic resin A, the higher the surface particle concentration ratio is. Low. Protrusions are formedinorganicBy covering the particles with a thin film of thermoplastic resin A,inorganicEven when the particles are densely distributed in the ultra-thin laminated film layer, the particles are firmly held by the laminated film layer and by extension, the base film layer of the thermoplastic resin B. Therefore, by making the surface layer particle concentration ratio below the above value,inorganicThe falling off of the particles is prevented, and the durability of the film surface is maintained high. Such a surface particle concentration ratio can be achieved by performing lamination by coextrusion.
[0029]
And the layer (C layer) which has an acrylic resin and a polyester resin as the main component is laminated | stacked on the film of the laminated structure of the film layer of the thermoplastic resin A and the film layer of the thermoplastic resin B as mentioned above, and this book The laminated film of the invention is completed.
[0030]
The layered structure may be any conceivable layered structure. However, when a coating is provided on the laminated film, it is desirable to provide a coating on at least the easy-adhesive layer (C layer), particularly as a thermal transfer material. In some cases, it is desirable that the stick prevention layer is directly provided on the A layer, and the sublimation ink layer is provided on the opposite surface (at least the C layer is provided).
[0031]
Lamination of the C layer is possible in each step in the biaxially oriented thermoplastic resin film production process, but since the C layer is an ultrathin layer, it is molded and fixed as the C layer or the entire film after the C layer is laminated. It is preferable that a roll or the like does not come into contact with the surface of the C layer. Therefore, for example, the C layer is preferably laminated before or after the width direction stretching in the sequential biaxial stretching in which the longitudinal direction stretching and then the width direction stretching are performed, or before the stretching in the simultaneous biaxial stretching. Laminating is industrially preferable, so-called in-line coating, in which coating is performed in a continuous film production process, but may be performed in a separate process dedicated for offline use.
[0032]
By laminating the layer mainly composed of the acrylic resin and polyester resin of the present invention as the C layer, it has excellent easy adhesion and excellent printing characteristics due to a synergistic effect with the biaxially oriented thermoplastic resin film. It is.
[0033]
The acrylic resin which is a constituent component of the easy-adhesion layer of the present invention is a conventionally known one and is not particularly limited. A well-known thing can be used as a monomer component which comprises an acrylic resin. For example, alkyl acrylate, alkyl methacrylate (the alkyl group is methyl group, ethyl 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.), hydroxy group-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide Amide group-containing monomers such as N-methoxymethylmethacrylamide and N-phenylacrylamide, amino group-containing monomers such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate, epoxy groups such as glycidyl acrylate and glycidyl methacrylate Monomers, carboxyl groups such as acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt, etc.) or monomers containing such salts are included, and these may be used in combination of one or more. Polymerized. Furthermore, these can be used in combination with other types of monomers.
[0034]
Examples of other types of monomers include sulfonic acid groups such as 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.) Monomers containing salts, monomers containing crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salts, sodium salts, potassium salts, ammonium salts, etc.) or salts thereof, 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.
[0035]
In addition, as the acrylic resin of the present invention, a modified polyester copolymer such as a block copolymer modified with acrylic, urethane, epoxy, or the like, a graft copolymer, or the like can also be used.
[0036]
The molecular weight of the acrylic resin of the present invention is preferably 100,000 or more, more preferably 300,000 or more from the viewpoint of adhesion.
[0037]
In the present invention, when an easy-adhesion layer is provided by a method of applying to the polyester film before the completion of the crystal orientation, and stretching and heat treatment to complete the crystal orientation (in-line coating), heat treatment at a high temperature is possible. In particular, it is particularly preferable because a uniform and thin easily adhesive layer can be obtained. In the case of laminating the easy-adhesion layer by the above method, it is preferable that the acrylic resin can be dissolved or emulsified and suspended in water from the viewpoint of environmental pollution and explosion resistance, and such acrylic resin has a hydrophilic group. Prepared by known methods such as copolymerization with monomers (acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof), emulsion polymerization using reactive emulsifiers and surfactants, suspension polymerization, soap-free polymerization be able to.
[0038]
The polyester resin which is a constituent component of the easy-adhesion layer of the present invention is a conventionally known one and is not particularly limited. The dicarboxylic acid component of the polyester resin includes terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2- Bisphenoxyethane-p, p′-dicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, and the like, and ester-forming derivatives thereof are mentioned.
[0039]
Examples of the glycol component of the polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol, trimethylolpropane, and the like.
[0040]
In order to make the polyester resin water-soluble, it is preferable to copolymerize a compound containing a carboxylate group or a compound containing a sulfonate group.
[0041]
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-2,3,4,5-tetracarboxylic acid, ethylenetetracarboxylic acid or the like, or alkali metal salts, alkaline earth metal salts, ammonium salts thereof. However, the present invention is not limited to this.
[0042]
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- Examples thereof include 1,4-bis (hydroxyethoxy) benzene and alkali metal salts, alkaline earth metal salts and ammonium salts thereof, but are not limited thereto.
[0043]
In addition, as the polyester resin, a modified polyester copolymer such as a block copolymer modified with acrylic, urethane, epoxy, or the like, a graft copolymer, or the like can also be used.
[0044]
The polyester resin of the present invention can be produced by a conventionally known production technique. For example, a polyester resin composed of terephthalic acid, isophthalic acid, trimellitic acid as a dicarboxylic acid component, and ethylene glycol and neopentyl glycol as a glycol component will be described. First esterification reaction of terephthalic acid, isophthalic acid, trimellitic acid and ethylene glycol or neopentyl glycol, and a second polycondensation reaction of the reaction product of the first stage. Depending on the stage, the production method can be mentioned.
[0045]
At this time, conventionally known alkali metals, alkaline earth metals, manganese, cobalt, zinc, antimony, germanium, titanium compounds, and the like are used as reaction catalysts.
[0046]
Further, the intrinsic viscosity of the polyester resin of the present invention is not particularly limited, but it is preferably 0.3 dl / g or more, preferably 0.35 dl / g or more, and more preferably 0.4 dl / g or more in terms of adhesiveness.
[0047]
The acrylic resin and the polyester resin may be mixed at an arbitrary ratio. However, in order to achieve the effects of the present invention more remarkably, the acrylic resin and the polyester resin may be mixed at the following ratio (the solid content weight ratio). It is desirable that the acrylic resin / polyester resin is 90/10 to 2/98, preferably 80/20 to 5/95, and more preferably 60/40 to 10/90.
[0048]
In the present invention, an easy-adhesion layer comprising acrylic resin and polyester resin as main constituent components is provided. However, addition of a melamine-based cross-linking agent is preferable because adhesion is further improved.
[0049]
The melamine-based crosslinking agent is a conventionally known one and is not particularly limited. For example, the melamine-based crosslinking agent has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group as a functional group in one molecule. Examples include basic methylated melamine resins, methylol-based melamine resins, methylol-based methylated melamine resins, and completely alkyl-type methylated melamine resins. Among them, hexamethylolated melamine resin is most preferable. Furthermore, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid in order to accelerate the thermal curing of the melamine crosslinking agent.
[0050]
The addition amount of the melamine-based crosslinking agent is 1 to 50 parts by weight, preferably 2 to 40 parts by weight, more preferably 5 to 20 parts by weight with respect to 100 parts by weight of the acrylic resin and the polyester resin. It is desirable.
[0051]
The easy-adhesion layer of the present invention is obtained by applying a coating composition mainly composed of the two structural components of the acrylic resin and the polyester resin, followed by drying and curing. It means 50% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.
[0052]
In the easy-adhesive layer, known additives within a range not inhibiting the effects of the present invention, such as antioxidants, heat stabilizers, weathering stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic Alternatively, inorganic fine particles, fillers, antistatic agents, nucleating agents, methylolated or alkylolized urea-based, epoxy-based, blocked isocyanate compounds, oxazoline compounds, and various other crosslinking agents may be blended.
[0053]
Although the thickness of a coating film is not specifically limited, Usually, 0.03-5 micrometers, Preferably it is 0.05-2 micrometers, More preferably, the range of 0.07 micrometer-0.5 micrometer is preferable. In particular, if it is too thin, it may cause poor adhesion.
[0054]
As a method for coating on the base film, known coating methods such as reverse coating, gravure coating, rod coating, and die coating can be used.
[0055]
Next, the present inventionFor sublimation type thermal transfer materialA method for producing the film will be described.
[0056]
  First, the thermoplastic resin AinorganicAs a method of incorporating particles, any of after polymerization, during polymerization, and before polymerization may be used, but a method of kneading into a polymer using a vent type twin screw extruder provides a film having a surface form within the scope of the present invention. It is effective for. Also,inorganicAs a method for adjusting the content of particles, a high concentration master is prepared by the above method, and this is applied during film formation.inorganicDilute with a thermoplastic resin substantially free of particlesinorganicThe method of adjusting the content of the particles is effective for obtaining a film having a surface form within the range of the present invention. Furthermore thisinorganicThe method of adjusting the melt viscosity, copolymerization component, etc. of the high-density master polymer to keep the crystallization parameter ΔTcg in the range of 30 to 80 ° C. is less likely to be stretched and the film having the surface form within the range of the present invention is obtained. It is effective.
[0057]
  Thus,inorganicAfter fully drying the pellet A containing particles, the pellet A is supplied to a known melt extruder, extruded from a slit-shaped die into a sheet, and cooled and solidified on a casting roll to produce an unstretched film. That is, these thermoplastic resins are laminated by using 2 or 3 extruders, 2 or 3 layer confluence block or die. When using the merge block method, the laminated portion is rectangular as described above, and the difference in viscosity (absolute value) between the two thermoplastic resins should be in the range of 0 to 2000 poise, preferably 0 to 1000 poise. It is effective for industrially producing a film having a surface form within the scope of the present invention stably and without unevenness in the width direction.
[0058]
  Next, this multilayer unstretched film is biaxially stretched to be biaxially oriented. The biaxial stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching method, but in the case of the sequential biaxial stretching method in which the film is stretched in the order of the longitudinal direction and the width direction, the film of the surface form within the scope of the present invention is stabilized. Thus, it is effective for industrial production without unevenness in the width direction. In the case of sequential biaxial stretching, stretching in the longitudinal direction is divided into 3 stages, particularly 4 stages or more, and is performed in the range of 40 to 150 ° C. and 3 to 6 times at a stretching speed of 1000 to 5000% / min. The method is effective to obtain a film having a surface morphology within the scope of the present invention. The stretching temperature and speed in the width direction are preferably in the range of 80 to 170 ° C. and 1000 to 20000% / min. The stretching ratio is preferably 3 to 10 times. Moreover, it can also extend | stretch in at least one direction of a longitudinal direction and the width direction as needed. Also if necessaryinorganicIt is also possible to use a method in which a very thin layer containing particles is provided and then the stretching is 9 times or more as the area stretching ratio (longitudinal direction magnification × width direction magnification). Next, this stretched film is heat-treated. The heat treatment conditions in this case are 140 to 280 ° C., preferably in the range of 160 to 260 ° C., and 0.5 to 60 seconds in any state of relaxation, fine stretching, and constant length in the width direction. However, it is desirable to use microwave heating in combination with the heat treatment because a film having the surface morphology of the present invention is easily obtained.
[0059]
The lamination time of the C layer in the present invention is most preferably a method in which it is applied during the film production process and stretched together with the substrate. For example, the melt-extruded film before crystal orientation is stretched about 2.5 to 5 times in the longitudinal direction, the surface to be continuously applied is subjected to corona discharge treatment, and the coating liquid is applied to the treated surface. The applied film is dried while passing through a zone heated stepwise, and stretched about 2.5 to 5 times in the width direction. Further, it is obtained by a method of continuously guiding to a heating zone of 150 to 250 ° C. to complete crystal orientation. In this heat treatment step, 3-12% relaxation heat treatment may be performed in the width direction or the longitudinal direction as necessary. The coating liquid used in this case is preferably an aqueous system from the viewpoint of environmental pollution and explosion resistance.
[0060]
The laminated film thus obtained isSublimation-type thermal transfer material by providing sublimation-type ink through an easy-adhesive layer and a stick prevention layer on the other sideIs preferably used.
[0061]
In particular, the film surface can be formed efficiently, with high density and uniform height projections, and by making the projections uniform with no coarse projections, not only the slipperiness of the base film is good, In thermal transfer material applications, printing characteristics are improved by increasing thermal conductivity during transfer. Further, by providing a layer mainly composed of an acrylic resin and a polyester resin, the adhesiveness to the sublimation ink is excellent, and it is particularly suitably used as a sublimation type thermal transfer material.
[0062]
[Measurement method and evaluation method of characteristic values]
The characteristic measuring method and the effect evaluating method in the present invention are as follows.
[0063]
(1)inorganicParticulateVolume averageDiameter, number of particles
  Remove the polymer from the film by plasma low-temperature ashing,inorganicExpose particles. The processing conditions are that the polymer is ashed.inorganicSelect the conditions under which the particles are not damaged as much as possible. ThatinorganicObserve the particles with a scanning electron microscope (SEM),inorganicThe particle image is processed with an image analyzer. The magnification of SEM is approximately 2000 to 10000 times, and the field of view is selected appropriately from approximately 10 to 50 μm per side in one measurement. By changing the observation location, the number of particles is 5000 or more, and the volume average diameter d is obtained from the particle size and its volume fraction by the following formula.
d = Σdi · Nvi where di is the particle size and Nvi is its volume fraction.
[0064]
  The number of particles isVolume averageFor those satisfying the diameter relationship, it is obtained from the volume fraction, and mm²Convert per hit.
[0067]
(2)inorganicParticle content
The thermoplastic resin dissolvesinorganicSelect a solvent that will not dissolve the particles,inorganicCentrifuge the particles from the thermoplastic resin,inorganicWith the ratio (wt%) to the total weight of the particlesinorganicThe particle content. In some cases, a combination of infrared spectroscopy is also useful.
[0068]
(3) Glass transition point Tg, cold crystallization temperature Tcc, crystallization parameter ΔTcg, and melting point
It was measured using DSC (Differential Scanning Calorimeter) type II manufactured by Perkin Elma. The DSC measurement conditions are as follows. That is, 10 mg of a sample is set in a DSC apparatus, melted at a temperature of 300 ° C. for 5 minutes, and then rapidly cooled in liquid nitrogen. The rapidly cooled sample is heated at 10 ° C./min, and the glass transition point Tg is detected. The temperature was further increased, and the crystallization exothermic peak temperature from the glassy state was taken as the cold crystallization temperature Tcc. The temperature was further raised and the melting peak temperature was taken as the melting point. The difference between Tcc and Tg (Tcc−Tg) is defined as the crystallization parameter ΔTcg.
[0069]
(4) Average height of surface protrusions
When scanning using a two-detector scanning electron microscope [ESM-3200, manufactured by Elionix Co., Ltd.] and a cross-section measuring apparatus [PMS-1, manufactured by Elionix Co., Ltd.] with the flat surface height of the film surface being zero. The height measurement values of the protrusions are sent to an image processing apparatus [IBAS2000, manufactured by Carl Zeiss], and a film surface protrusion image is reconstructed on the image processing apparatus. Next, a circle-equivalent diameter is obtained from the area of each protrusion obtained by binarizing the protrusion portion in this surface protrusion image, and this is used as the average diameter of the protrusion. Further, the highest value among the binarized individual protrusions is defined as the height of the protrusion, and this is obtained for each protrusion. This measurement was repeated 500 times at different locations, the number of protrusions was determined, and the average height of all the measured protrusions was taken as the average height. Moreover, the magnification of a scanning electron microscope selects the value between 1000 times and 8000 times. In some cases, the height information obtained using a high-precision optical interference type three-dimensional surface analyzer (TOPO-3D manufactured by WYKO, objective lens: 40 to 200 times, use of a high-resolution camera is effective) is described above. It may be read as the SEM value.
[0070]
(5) Surface particle concentration ratio
Using secondary ion mass spectrum (SIMS),inorganicThe analysis is performed in the thickness direction with the concentration ratio of the element having the highest concentration among the elements derived from the particles and the carbon element concentration ratio of the thermoplastic resin as the particle concentration. The ratio of the particle concentration A at the outermost layer particle concentration (point of depth 0) measured by SIMS and the highest concentration B obtained by continuing the analysis in the depth direction, A / B, was defined as the surface particle concentration ratio. Measuring equipment and conditions are as follows.
[0071]
measuring device
Secondary ion mass spectrometer (SIMS)
West Germany, A-DIDA3000 manufactured by ATOMICA
Measurement condition
Primary ion species: O₂ ⁺
Primary ion acceleration voltage: 12 kV
Primary ion current: 200 nA
Raster area: 400μm
Analysis area: 30% gate
Measuring vacuum: 6.0 × 10 9 Torr
E-GUN: 0.5kV-3.0A
(6) Single particle index
Photographic observation of the cross section of the film with a transmission electron microscope (TEM),inorganicDetect particles. If the observation magnification is about 100,000, one piece that cannot be further dividedinorganicParticles can be observed.inorganicThe total area occupied by the particles is A, of which 2 or moreinorganicWhen the area occupied by the aggregate in which the particles are aggregated is defined as B, (AB) / A is defined as a single particle. The TEM conditions are as follows: 1 field of view area: 2 μm²Measure 500 fields of view at different locations.
[0072]
・ Device: JEM-1200EX manufactured by JEOL
-Observation magnification: 100,000 times
・ Section thickness: about 1000 angstroms
(7) Particle size ratio
In the measurement of (1) above,inorganicIt is the ratio of the average value of the major axis / the average value of the minor axis of the particles. That is, it is obtained by the following formula.
[0073]
Major axis = ΣD1i / N
Minor axis = ΣD2i / N
D1i and D2i are individualinorganicThe major axis (maximum diameter), minor axis (shortest diameter), and N are the total number of particles.
[0074]
(8) Thickness of the thermoplastic resin A layer in the laminated film
Using a secondary ion mass spectrometer (SIMS), in the film having a depth of 3000 nm from the surface layerinorganicThe highest concentration of particlesinorganicAnalysis is performed in the thickness direction from the surface to a depth of 3000 nm with the concentration ratio of carbon element between the element caused by the particles and the carbon (M + / C +) of the polyester as the particle concentration. In the surface layer, the particle concentration is low due to the interface of the surface, and the particle concentration increases as the distance from the surface increases. In the case of the film of the present invention, the particle concentration once reached the maximum value starts to decrease again. Based on this concentration distribution curve, the depth at which the surface layer particle concentration is ½ of the maximum value (this depth is deeper than the depth at which the maximum value is reached) was determined, and this was taken as the laminated thickness. The conditions are the same as in (5).
[0076]
(9) Intrinsic viscosity of copolyester: [η]
It measured at 25 degreeC using the o-chlorophenol solvent.
[0077]
(10) Sublimation ink adhesion
The following sublimation type ink is applied using a bar coater so that the thickness after drying is about 5 μm. After application, it is dried at 120 ° C for 2 minutes, left for 24 hours at 25 ° C and 60% relative humidity, and then a scotch-mending tape (manufactured by Sumitomo 3M Co., Ltd.) is pasted on the sublimation ink layer and pressed firmly by hand. After that, it peels in the 180 ° C. direction. The following five-step evaluation was performed according to the state of the sublimation ink remaining on the base film side at this time. (◎) and (○) indicate good adhesion.
[0078]
A: 100% of the ink on the peeled surface remains
○: 〃 More than 80% remaining
△: も の 50% or more remaining
×: 〃 Less than 50% remaining
XX: Exfoliate completely without resistance
"Sublimation ink composition"
Disperse dye KST-B-136 (manufactured by Nippon Explosives) 4% by weight
・ Ethyl hydroxyethyl cellulose 6% by weight
・ Methyl ethyl ketone 45% by weight
・ Toluene 45% by weight
(11) Printing characteristics of thermal transfer material
In the above (10), the printing characteristics of the sublimation type thermal transfer material prepared by providing the stick prevention layer was visually checked using a sharp color video printer GZ-P11W (manufactured by Sharp Corporation). Evaluated by criteria.
[0079]
A: Very good printing state
○: Good printing characteristics
Δ: Somewhat bad
×: Remarkably bad
(12) Thickness of coating layer
Using a transmission electron microscope HU-12 manufactured by Hitachi, Ltd., an ultra-thin film section of the laminated film was observed to determine the thickness.
[0080]
【Example】
EXAMPLES Next, although this invention is demonstrated based on an Example, it is not necessarily limited to this.
[0081]
Example 110Comparative Examples 1-7
  Volume averageDifferent diameterRuAn ethylene glycol slurry containing spherical silica particles derived from colloidal silica was prepared, and the ethylene glycol slurry was heat treated at 190 ° C. for 1.5 hours, and then subjected to a transesterification reaction with dimethyl terephthalate, and then subjected to polycondensation. Pellets of polyethylene terephthalate (hereinafter abbreviated as PET) containing 0.01 to 55% by weight were prepared. A thermoplastic resin A was prepared using the pellets, and PET containing 0.3% by weight of spherical silica particles having a diameter of 0.03 μm was produced by a conventional method to obtain a thermoplastic resin B. Each of these polymers was dried under reduced pressure (3 Torr) at 180 ° C. for 3 hours. The thermoplastic resin A is supplied to the extruder 1 and melted at 285 ° C., and the thermoplastic resin B is supplied to the extruder 2 and melted at 280 ° C., and these polymers are merged in a merge block having a rectangular laminated portion. The films were laminated, wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to form an unstretched film having a three-layer structure having a thermoplastic resin A layer on two or both sides. At this time, the discharge amount of each extruder was adjusted to adjust the total thickness and the thickness of the thermoplastic resin A layer. This unstretched film was stretched 3.5 times in the longitudinal direction at a temperature of 90 ° C. This stretching was performed in four stages with a difference in peripheral speed between two sets of rolls. This uniaxially stretched film was coated in-line, and the coated uniaxially stretched film was stretched 4.0 times in the width direction at 100 ° C. at a stretching speed of 2000% / min using a stenter, and under a tension of 2 kg / m in the longitudinal direction. Heat treatment was carried out at 5 ° C. for 5 seconds to obtain a biaxially oriented laminated film having a total thickness of 7 μm and a thermoplastic resin A layer thickness of 0.05 to 6 μm. The parameters and laminated structure of these films are as shown in Tables 1 and 2.
[0082]
Although it will not specifically limit as C layer laminated | stacked on the laminated | multilayer film of this invention if an acrylic resin and a polyester resin are the main structural components, A water-based coating agent is preferable. The coating composition constituting the C layer is as shown in Tables 1 and 2. However, a water-based acrylic resin coating obtained by copolymerizing methyl methacrylate / ethyl acrylate / acrylic acid / N-methylolacrylamide at 72/25/2/1 (weight ratio) as an acrylic resin. An aqueous polyester resin coating material obtained by condensation polymerization of terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid / ethylene glycol / 1,4-butanediol at a ratio of 30/15/5/25/25 (weight ratio) as a polyester resin. Using.
[0083]
The results are shown in Tables 1 and 2.
[0084]
Example11
A laminated film of the present invention in which a C layer was laminated was obtained in the same manner as in Example 1 except that polyethylene-2,6-naphthalate was used instead of polyethylene terephthalate as the base film. The results are shown in Table 1.
[0085]
[Table 1]

[Table 2]

[0086]
【The invention's effect】
  With thermoplastic resin AinorganicThe film A mainly composed of particles is laminated on at least one surface of the film B mainly composed of the thermoplastic resin B, and the film A has a thickness of 0.005 to 5 μm and is contained in the film A. Of the particlesVolume averageThe diameter is 0.1 to the lamination thickness3A biaxially oriented thermoplastic resin film in which the content of the particles in the film A is 0.1 to 50% by weight, the main component being an acrylic resin and a polyester resin on at least one side of the laminated film It is a laminated film formed by laminating layers (C layer), excellent in easy adhesion and printing characteristics,Sublimation type thermal transfer materialIs preferably used.

Claims (2)

A film A mainly composed of a thermoplastic resin A and inorganic particles is laminated on at least one surface of a film B mainly composed of a thermoplastic resin B, and the film A has a thickness of 0.005 to 5 μm. Biaxially oriented thermoplasticity in which the volume average diameter of the particles contained in A is 0.1 to 3 times the thickness of the film A, and the content of the particles in the film A is 0.05 to 50% by weight. A laminated film for a sublimation type thermal transfer material, which is a resin laminated film, wherein a layer (C layer) mainly comprising an acrylic resin and a polyester resin is formed on at least one surface of the laminated film.   2. The laminated film for a sublimation type thermal transfer material according to claim 1, wherein the biaxially oriented thermoplastic resin laminated film comprises a polyethylene terephthalate film or a polyethylene-2,6-naphthalate film.