CN101746168B - Basal membrane for hydraulic transfer printing - Google Patents

Abstract

The present invention provides a base film for hydraulic transfer printing that not only has excellent transfer printing suitability, but also has excellent solubility or dispersibility of a polyvinyl alcohol-based film and can improve productivity. The present invention relates to a base film for hydraulic transfer printing, comprising a polyvinyl alcohol film, wherein the polyvinyl alcohol film contains a polyvinyl alcohol resin, and the polyvinyl alcohol resin contains A polyvinyl alcohol-based resin (A1) having a viscosity of 15 to 50 mPa·s in an aqueous solution by weight and a polyvinyl alcohol-based resin (A2) having a viscosity of 1 to 10 mPa·s in a 4% by weight aqueous solution at 20°C.

Description

Base film for hydraulic transfer printing

technical field

The present invention relates to a base film for hydraulic transfer printing which can be used floating on a liquid surface, especially a water surface, and can smoothly transfer a pattern printed on the surface of a film to an object to be transferred.

Background technique

Conventionally, as a method of printing a pattern on the surface of a three-dimensional molded product having a complicated surface shape, the following method is known: using a transfer film having a pattern-formed printing layer on the surface of a base film, and making the above-mentioned transfer film After the film floats on the liquid surface (water surface) with the printing layer on top, press the molded body (transferred object) for transferring the printing layer from above, and transfer the printing layer of the transfer film by hydraulic pressure to the surface of the molding. As the base film for hydraulic transfer printing, a polyvinyl alcohol-based film using a polyvinyl alcohol-based resin as a forming material is used. From the viewpoint of film strength, a film with a viscosity of 4% by weight aqueous solution at 20°C is usually used. 50mPa·s polyvinyl alcohol resin film.

In addition, in such a hydraulic transfer method, various base films have been studied according to the purpose thereof. For example, Patent Document 1 proposes a polyvinyl alcohol-based film composed of a polyvinyl alcohol-based resin having an average degree of polymerization of 300 to 3000 and an average degree of saponification of 50 to 97 mol%. Polyvinyl alcohol resins having different average degrees of saponification are blended. In addition, Patent Document 2 proposes an ultra-high degree of polymerization polyvinyl alcohol resin with an average degree of polymerization of 3200 or more and an average degree of saponification of 65 to 95 mol%, and a polyvinyl alcohol resin with an average degree of polymerization of less than 3200 and an average degree of saponification of 65 to 95 mol%. A polyvinyl alcohol film made by mixing vinyl alcohol resins. In addition, in Patent Document 3, it is also proposed to contain polyvinyl alcohol resin with an average degree of saponification of 70 to 98 mol%, carboxyl and/or sulfonic acid group-modified polyvinyl alcohol resin and boron compound with an average degree of saponification of 70 mol% or more. The formed polyvinyl alcohol film.

Patent Document 1: Japanese Patent Application Laid-Open No. 55-25330

Patent Document 2: Japanese Patent Application Laid-Open No. 7-117327

Patent Document 3: Japanese Patent Laid-Open No. 2003-11590

Contents of the invention

However, the hydraulic transfer method using the polyvinyl alcohol-based film disclosed in the above-mentioned patent document can obtain a good pattern, but the dissolution or dispersibility of the transferred polyvinyl alcohol-based film is not sufficient. If the dissolution or dispersibility of the transferred polyvinyl alcohol film is not sufficient, the polyvinyl alcohol film may remain on the surface of the pattern, and the protective layer applied to protect the surface after transfer may be partially peeled off. Better film dissolution or dispersibility is desired.

Furthermore, when the following transfer method is adopted, the transfer method is as follows: a hydrophobic transfer layer soluble in an organic solvent is formed on the surface of the base film, and then the base film is positioned below to float on the water surface, After coating the active agent on the layer to activate the above-mentioned transfer layer, the transfer object is pressed on the above-mentioned transfer layer, the transfer layer is transferred to the surface of the transfer object, and then the base film is removed. The transferred object printed with the above transfer layer is subjected to at least one of active energy ray irradiation and heating to cure the transfer layer, thereby fixing the pattern transferred to the transferred object. Since no moisture enters, the solubility of the base film is particularly problematic in terms of the swelling behavior of the transfer film, and a base film with better solubility or dispersibility is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a base film for hydraulic transfer printing that not only has excellent transfer printing suitability, but also has excellent solubility or dispersibility of polyvinyl alcohol-based films and can improve productivity.

In order to achieve the above object, the present inventors have repeatedly conducted in-depth research, focused on the resin composition of the base film, and conducted research centering on it. The polyvinyl alcohol-based resin, as a resin composition constituting the polyvinyl alcohol-based film, not only has excellent transfer printing characteristics, but also has excellent dissolution or dispersibility of the transferred polyvinyl alcohol-based film, and the present invention has been completed.

The gist of the present invention is as follows.

1. A base film for hydraulic transfer printing, containing polyvinyl alcohol film, characterized in that, said polyvinyl alcohol film contains polyvinyl alcohol resin, and said polyvinyl alcohol resin contains A polyvinyl alcohol-based resin (A1) having a viscosity of 15 to 50 mPa·s in a 4 wt % aqueous solution and a polyvinyl alcohol resin (A2) having a viscosity of 1 to 10 mPa·s in a 4 wt % aqueous solution at 20°C.

2. The base film for hydraulic transfer printing as described in (1), wherein the viscosity of the polyvinyl alcohol-based resin (A2) at 20° C. in a 4% by weight aqueous solution is higher than that of the polyvinyl alcohol-based resin (A1) at At 20°C, the viscosity of a 4% by weight aqueous solution is 5-50% lower.

3. The base film for hydraulic transfer printing as described in (1) or (2), wherein the compounding amount of the polyvinyl alcohol-based resin (A2) is: 10 to 50 parts by weight.

4. The base film for hydraulic transfer printing as described in any one of (1) to (3), wherein the polyvinyl alcohol resin (A1) has an average degree of saponification of 70 to 98 mol%, polyethylene The average degree of saponification of the alcohol resin (A2) is 70 to 98 mol%.

5. The base film for hydraulic transfer printing according to any one of (1) to (4), wherein the average degree of saponification of the polyvinyl alcohol resin (A1) and the polyvinyl alcohol resin (A2) The difference in the average degree of saponification is 3 mol% or less.

6. The base film for hydraulic transfer printing according to any one of (1) to (5), wherein the polyvinyl alcohol-based film has a thickness of 20 to 50 μm.

7. The base film for hydraulic transfer printing as described in any one of (1) to (6), used in the hydraulic transfer method, in the hydraulic transfer method, a soluble organic compound is formed on the surface of the base film. A hydrophobic transfer layer made of a solvent, and then the base film is placed below and floats on the water surface, an active agent is coated on the transfer layer to activate the transfer layer, and the transfer object is pressed on the transfer layer , transfer the transfer layer to the surface of the object to be transferred, and then remove the base film, and then, by performing at least one of active energy ray irradiation and heating on the object to be transferred on which the transfer layer is transferred, the transferred The printed layer is cured, thereby fixing the pattern transferred to the object to be transferred.

The base film for hydraulic transfer printing of the present invention not only has excellent transfer printing characteristics, but also has the effect of excellent dissolution or dispersibility of the polyvinyl alcohol film after transfer, and can be used in the process of using active energy ray irradiation and heating. At least one method of curing the transfer layer, thereby fixing the pattern transferred to the object to be transferred, exerts a remarkable excellent effect, and can be widely used in interior and exterior decorations of automobiles and exterior decorations of mobile phones , Various electrical products, building materials, household, daily necessities, etc. hydraulic transfer printing applications.

Detailed ways

Hereinafter, the present invention will be described in detail.

The base film for hydraulic transfer printing of the present invention (hereinafter, may be simply referred to simply as a base film) includes a polyvinyl alcohol-based film.

In the present invention, "comprising a polyvinyl alcohol film" also includes the case where other layers (film, coating film, etc.) basement membrane.

The polyvinyl alcohol film is formed into a film using a polyvinyl alcohol (hereinafter abbreviated as PVA) resin. In the present invention, as the PVA resin, a 4 wt. A PVA-based resin (A1) of ~50 mPa·s and a PVA-based resin (A2) having a viscosity of 1 to 10 mPa·s in a 4% by weight aqueous solution at 20°C.

Here, the so-called PVAs refer to PVA itself or products modified by various modifying materials such as PVA. the following.

Examples of the above-mentioned modifying materials include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; acrylic acid, methacrylic acid, crotonic acid, maleic acid, Unsaturated acids such as toric anhydride and itaconic acid or their salts or mono- or di-alkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; vinylsulfonic acid, Olefin sulfonic acids such as allyl sulfonic acid and methallyl sulfonic acid or their salts; alkyl vinyl ethers; polyoxyethylene(meth)allyl ether, polyoxypropylene(meth)allyl Polyoxyalkylene (meth)allyl ethers such as ethers; polyoxyalkylene (meth)acrylates such as polyoxyethylene (meth)acrylates and polyoxypropylene (meth)acrylates; polyoxyethylene (meth)acrylates ) acrylamide, polyoxypropylene (meth)acrylamide and other polyoxyalkylene (meth)acrylamide; polyoxyethylene [1-(meth)acrylamide-1,1-dimethylpropyl] ester, poly Oxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine, diacryl acetone amide, N-acrylamidomethyl trimethyl ammonium chloride, allyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride, dimethyl allyl vinyl ketone, N-vinyl pyrrolidone, Vinyl chloride, vinylidene chloride, etc. These other monomers may be used alone or in combination of two or more.

In addition, as the PVA resin, it is also preferable to use a PVA resin with a 1,2-diol bond on the side chain. The PVA resin with a 1,2-diol bond on the above-mentioned side chain can be obtained by, for example, the following method: (1) A method of saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, (2) A method of saponifying and decarboxylation a copolymer of vinyl acetate and ethylene carbonate, (3) A method of saponifying and ketalizing a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane, (4) making vinyl acetate and glycerol mono A method for the saponification of copolymers of allyl ether, etc.

The PVA-based resin (A1) used in the present invention needs to have a viscosity of 15 to 50 mPa·s, preferably 15 to 45 mPa·s, particularly preferably 16 to 40 mPa·s, in a 4% by weight aqueous solution at 20°C. If the viscosity of the 4% by weight aqueous solution of the PVA-based resin (A1) is too low, the strength of the film will be insufficient, which may cause cracks during use. If the viscosity is too high, the solubility will be insufficient.

In addition, the viscosity of the above-mentioned 4% by weight aqueous solution at 20°C was measured in accordance with JIS K 6726.

In addition, the average degree of saponification of the PVA-based resin (A1) is preferably in the range of 70 to 98 mol%, particularly preferably in the range of 75 to 95 mol%, and still more preferably in the range of 80 to 90 mol%. When the average saponification is too low or too high, the solubility tends to decrease.

In addition, the average degree of saponification of the above-mentioned PVA-based resin is measured in accordance with JIS K 6726.

The said PVA-type resin (A1) can be normally obtained by selecting suitably from a commercial item.

The PVA-based resin (A2) used in the present invention needs to have a viscosity of 1 to 10 mPa·s, preferably 2 to 9 mPa·s, particularly preferably 3 to 8 mPa·s, in a 4% by weight aqueous solution at 20°C. If the viscosity of the 4% by weight aqueous solution of the PVA-based resin (A2) is too low, it will be difficult to produce a stable resin, and if the viscosity is too high, the effect of improving solubility will be lost.

In addition, the average degree of saponification of the PVA-based resin (A2) is preferably in the range of 70 to 98 mol%, particularly preferably in the range of 75 to 95 mol%, and still more preferably in the range of 80 to 90 mol%. When the average saponification is too low or too high, there is a tendency for the film to generate internal turbidity and cause poor appearance.

The said PVA-type resin (A2) can normally select suitably from a commercial item, and can obtain it.

In the present invention, when comparing the viscosity of a 4% by weight aqueous solution of the PVA-based resin (A1) and the viscosity of a 4% by weight aqueous solution of the PVA-based resin (A2), the PVA-based resin (A2) is preferred in terms of solubility and film strength. The viscosity of the 4% by weight aqueous solution of the PVA resin (A1) is 5-50% smaller than the viscosity of the 4% by weight aqueous solution of the PVA resin (A1), particularly preferably 10-50% smaller, more preferably 15-47% smaller, and especially preferably 15-30% smaller . Compared with the viscosity of the 4% by weight aqueous solution of the PVA-based resin (A1), the viscosity of the 4% by weight aqueous solution of the PVA-based resin (A2) tends to be difficult to obtain when the viscosity of the 4% by weight aqueous solution of the PVA-based resin (A2) is too small. The improvement effect tends to be small.

In addition, when comparing the average degree of saponification of the PVA-based resin (A1) and the average degree of saponification of the PVA-based resin (A2), the difference is preferably 3 mol% or less, particularly preferably 2 mol% or less, from the viewpoint of a good film appearance. More preferably, it is 1.5 mol% or less, and it is especially preferable that there is almost no difference substantially. When the difference in the average saponification degree is too large, the internal turbidity tends to increase.

In addition, the content ratio of the PVA-based resin (A1) and the PVA-based resin (A2) is preferably 10 parts by weight of the PVA-based resin (A2) based on 100 parts by weight of the PVA-based resin (A1) from the viewpoint of film strength and solubility. ~50 parts by weight, particularly preferably 10~40 parts by weight, more preferably 15~35 parts by weight. When the content of the PVA-based resin (A2) is too small, the effect of improving solubility tends to disappear, and when too large, the film strength tends to be insufficient.

In addition, in the present invention, the above-mentioned PVA-based resin (A1) and PVA-based resin (A2) should be used in combination, but PVA-based resins other than PVA-based resin (A1) and PVA-based resin (A2) may be used in combination.

Thus, in the present invention, the PVA-based resin (A1) and the PVA-based resin (A2) should be used as the PVA-based resin to form a PVA-based film, and a plasticizer is usually blended when forming the film.

Examples of the plasticizer include glycerin such as glycerin, diglycerin, and triglycerin; alkylene glycols such as triethylene glycol, polyethylene glycol, polypropylene glycol, and dipropylene glycol; trimethylolpropane, etc. . These can be used alone or in combination of two or more.

The content of the plasticizer can be appropriately set according to the desired physical properties of the PVA-based film. For example, it is usually 5 parts by weight or less, preferably 0.05 to 4 parts by weight, based on 100 parts by weight of the total amount of the PVA-based resin. If the content of the above-mentioned plasticizer is too small, the plasticizing effect will be low, and there is a tendency to cause the resulting PVA-based film to break. If the content is too large, the dimensional stability when printing a pattern on the film surface will be poor, and it will be difficult to perform high-precision printing. Tendency for multicolor printing.

Moreover, in addition to the above-mentioned PVA-based resin and plasticizer, various additives can be compounded as needed.

For example, a surfactant may be blended in order to improve the peelability between metal surfaces such as drums and belts of a PVA-based film-forming apparatus and the produced film. Examples of the surfactant include polyoxyethylene nonylphenyl ether, polyoxyethylene octylnonyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkylallyl ether, polyoxyethylene Sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyalkylene Polyoxyethylene alkylamines such as base ether phosphate monoethanolamine salt, polyoxyethylene laurylamine, polyoxyethylene stearamide, etc. These surfactants may be used alone or in combination of two or more. Among them, polyoxyalkylene alkyl ether phosphate monoethanolamine salt, polyoxyethylene alkylamine, and polyoxyethylene sorbitan monolaurate are preferably used from the viewpoint of releasability.

The content of the surfactant is usually preferably 0.01 to 5 parts by weight, more preferably 0.03 to 4.5 parts by weight, based on 100 parts by weight of the total amount of the PVA-based resin and the plasticizer. If the content of the above-mentioned surfactant is too small, there is a tendency that the peelability of the metal surface of the drum, the transmission belt, etc. of the film forming device and the produced film will be reduced, making it difficult to manufacture. On the contrary, if the content is too large, there will be bleeding. The pattern printing layer tends to come off on the surface of the film.

In addition, a cross-linking agent may also be added to the PVA-based resin. As the cross-linking agent, as long as it is a substance that undergoes a cross-linking reaction with the PVA-based resin, for example: K ₃ C ₆ H ₅ O ₇ (citric acid tris Potassium), boric acid, calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), aluminum potassium borate, ammonium borate (ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc.), boric acid Cadmium (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate (potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate, etc.), silver borate (silver metaborate, silver tetraborate, etc.), Copper borate (copper borate, copper metaborate, copper tetraborate, etc.), sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.), lead borate (metaborate lead, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, barium metaborate, barium diborate, barium tetraborate, etc.), Bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.), manganese borate (manganese borate, manganese metaborate, manganese tetraborate, etc.), lithium borate ( Lithium metaborate, lithium tetraborate, lithium pentaborate, etc.), and boron compounds such as borate minerals such as borax, borax tetrahydrate, platenite, magnesite, suianite, boronite, etc. These crosslinking agents may be used alone or in combination of two or more. Among the above crosslinking agents, borax and boric acid are preferably used.

The amount of the crosslinking agent is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the total amount of the PVA-based resin.

In addition, antioxidants (phenols, amines, etc.), stabilizers (phosphates, etc.), colorants, fragrances, extenders, defoamers, antirust agent, ultraviolet absorber, inorganic powder, organic powder (starch, polymethylmethacrylate, etc.), and other water-soluble polymer compounds (sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, shell polysaccharide, chitin, methyl cellulose, hydroxyethyl cellulose, etc.), etc.

The PVA-based thin film constituting the base film of the present invention can be produced, for example, as follows. First, various raw materials such as the above-mentioned PVA-based resin, plasticizer, surfactant, and water are blended in predetermined blending amounts to prepare a film-forming material. Next, the film-forming material is cast from a T-die onto a film-forming belt or a film-forming drum, dried, and preferably further heat-treated to form a thin film. As temperature conditions of the said heat treatment, it is preferable to set it as 70-100 degreeC.

The above-mentioned heat treatment method is not particularly limited, and examples thereof include methods such as hot rolls (including calender rolls), hot air, far-infrared rays, and induction heating. In addition, the surface to be heat-treated is preferably the surface opposite to the surface in contact with the film forming belt or the film forming drum, but may be sandwiched therebetween. In addition, the water content of the heat-treated film is generally preferably about 4% by weight to about 8% by weight. In addition, the water content of the film after the heat treatment is usually preferably 3 to 7% by weight.

More specifically, it is preferable to pass the film through one or more heat treatment rolls with a surface temperature of 70 to 100° C. after peeling the film from the film forming belt or the first film forming drum among the film forming drums before winding it up. Here, the above-mentioned film forming belt refers to a device that has an endless belt running between a pair of rollers and dries the film forming material flowing out of the T-die while casting it on the endless belt. The above-mentioned endless belt is preferably made of, for example, stainless steel, and its outer peripheral surface is mirror-finished.

In addition, the above-mentioned first film-forming drum refers to a drum-type film-forming machine located on the most upstream side in a film-forming machine that casts the film-forming material flowing out of the T-die onto one or more rotating drum-type rolls and dries it. roll. In addition, after peeling off from the film forming belt or the first film forming drum until winding up, the following process is shown: the film forming material discharged from the T-die or the like is placed on the film forming belt or the first film forming drum It is dried to form a film, then peeled off from the film forming belt or the first film forming drum, preferably passes through a heat treatment machine, and is wound up with a coiler. The heat treatment by the above-mentioned heat treatment machine is preferably performed at 70 to 100°C, more preferably at 75 to 98°C. That is, if the above-mentioned heat treatment temperature is too low, the swelling factor of the obtained base film tends to be extremely high, and the pattern tends to elongate before transfer, resulting in reduced patternability. Conversely, if the heat treatment temperature is too high, the pattern tends to be damaged for molded articles requiring conformability. In addition, the time required for the above heat treatment depends on the surface temperature of the heat treatment roll, but is usually preferably 0.5 to 60 seconds, particularly preferably 0.5 to 30 seconds, and more preferably 0.5 to 15 seconds. If the time is too short, the heat treatment tends to be insufficient, and if the time is too long, the heat treatment tends to be excessive and the productivity tends to decrease. The above-mentioned heat treatment is usually performed with a separate heat treatment roll immediately after the drying roll treatment for drying the film.

Thereby, the PVA-type film which comprises the base film for hydraulic transfer printing of this invention can be obtained.

In addition, in the present invention, the water content of the PVA-based film is preferably 2 to 6% by weight, more preferably 3 to 5% by weight. If the water content is too small, the film tends to curl during transfer. If the water content is too high, although the curl becomes small, problems such as printing position shifts tend to occur in practical applications such as printing.

In addition, the water content of the PVA-based film can be measured using, for example, a Karl-Fisher moisture meter (manufactured by Kyoto Denshi Kogyo Co., Ltd., MKS-210).

As a method of adjusting the water content of the above-mentioned PVA-based film, for example, the methods shown below may be mentioned. That is, it is possible to set the water content of the PVA-based film within the above-mentioned range according to the method of adjusting the water content described below.

(1) Moisture content adjustment is performed by increasing or decreasing the temperature of a dryer when forming a film by drying a PVA-dissolved dope to humidify or dehumidify the PVA-based film. Since the temperature of the dope affects the drying efficiency, the temperature of the above-mentioned dope is adjusted within the range of 70°C to 98°C. In addition, from the viewpoint of moisture regulation, when drying, it is preferable to dry in at least two or more hot air dryers with a temperature gradient between 150°C and 50°C, more preferably between 145°C and 60°C, for 1 to 15 minutes, more preferably drying 1 to 12 minutes.

If the gradient range of the drying temperature is too large or the drying time is too long, the drying tends to be over-dried. Conversely, if the gradient range of the drying temperature is too small or the drying time is too short, the drying tends to be insufficient.

The above-mentioned temperature gradient is to change the drying temperature step by step between 150 and 50°C. Generally, the following method is effective: gradually increase the temperature from the beginning of drying, and temporarily reach the set value before reaching the predetermined moisture content. The highest drying temperature in the drying temperature range, and then gradually reduce the drying temperature, and finally reach the target moisture content. This is done to control crystallinity, exfoliation, productivity, etc., for example: The temperature gradient settings such as 90°C can be appropriately selected for implementation.

(2) Before the PVA-based film is wound up, the PVA-based film is humidified and dehumidified by passing through a humidity-conditioning tank to adjust the water content.

(3) Heat treatment is performed before winding up of the PVA-based film, thereby dehumidifying the PVA-based film and adjusting the water content.

In addition, the total light transmittance of the above-mentioned PVA-based film is usually 80% or more, preferably 85-99%, particularly preferably 85-95%. This is because, when the total light transmittance is too low, it tends to be difficult to match color at the time of printing.

In addition, the total light transmittance of the PVA-based film can be measured using, for example, a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., NDH 2000).

The retardation value of the PVA-based film is preferably 40 nm or less, more preferably 35 nm or less. The retardation value is represented by the product of the birefringence of the PVA-based film and the film thickness (birefringence x film thickness), and the birefringence is determined by the degree of molecular orientation of the film given in the film manufacturing process or the like. If the above-mentioned retardation value is too high, wrinkles tend to form on the surface of the base film, hindering the formation of the printed layer, or the base film stretches in an uneven state when floating on the water surface, deforming the printed pattern. Therefore, as a method of making the retardation value 40nm or less, for example, a PVA-based film is sufficiently dried on a drum or a belt, and adjusted by winding it up without applying tension in a subsequent process. method. In addition, the lower limit of the retardation value is usually 3 nm.

In addition, the elongation at break of the PVA-based film is preferably 150% or more, more preferably 180% or more, under 23° C., 50% RH humidity-conditioning conditions. This is because, when the elongation at break is too low, breakage occurs during printing or the followability during transfer tends to decrease. In addition, the upper limit of the elongation at break is usually 300%.

In addition, the elongation at break of the PVA-based film is measured in accordance with JIS K 7127 (1999).

The thickness of the PVA-based thin film formed as described above is preferably set in the range of 20 to 50 μm, more preferably 23 to 47 μm, particularly preferably 25 to 45 μm. If the film thickness is too thin, the printing film will swell quickly, which is not conducive to transfer. If the thickness is too thick, the film will remain on the transfer material, or the concentration of PVA resin in the water in the transfer liquid will increase rapidly. And the tendency to increase the drainage load.

The PVA-based film (film roll) obtained by film formation is preferably subjected to conventionally known moisture-proof packaging treatment so that the moisture content described above does not change, and stored in a suspended state in an environment of 10-25°C.

Next, a hydraulic transfer printing method using the base film of the present invention will be described.

As the hydraulic transfer method using the base film of the present invention, it can be applied to various conventional hydraulic transfer methods, for example: (1) the hydraulic transfer method of the continuous method, (2) the hydraulic transfer method of the intermittent method wait.

First, the hydraulic pressure transfer method of the above (1) continuous method will be described.

That is, a predetermined pattern is printed on the surface of the base film obtained as above. After that, an active agent is coated on the above-mentioned pattern printing surface. Next, limit the width direction of the above-mentioned base film relative to the flow direction, such as 1.3 times or less, so that the base film stretches after absorbing water without blurring the pattern, and the base film floats on the liquid surface with the pattern printing surface coated with the active agent as the top and move. The transfer target is pressed from above the moving base film, and the pattern printed on the base film surface is transferred to the surface of the transfer target and fixed, whereby hydraulic transfer printing is performed. Then, after fixing, the base film is removed, and the object to be transferred on which the pattern has been transferred is sufficiently dried to obtain the target product.

On the other hand, the hydraulic transfer printing method of the above-mentioned (2) batch method will be described.

That is, a predetermined pattern is printed on the surface of the base film obtained as above. After that, an active agent is coated on the above-mentioned pattern printing surface. Next, similar to the above-mentioned continuous method, the above-mentioned base film is set in vertical and horizontal directions such as 1.3 times or less vertical and horizontal restrictions, so that the base film is stretched after water absorption without blurring the pattern, and the pattern printing surface coated with the active agent is used as the upper side. The basement membrane floats on the liquid surface. Next, in a static state, the object to be transferred is pressed from above the above-mentioned base film, and the pattern printed on the surface of the base film is transferred to the object to be transferred and sufficiently fixed, thereby performing hydraulic transfer printing. After the fixation, the base film is removed, and the transferred object on which the pattern has been transferred is fully dried to obtain the target product.

The active agent coated on the above-mentioned pattern printing surface is not particularly limited, and a substance obtained by adding a resin to a solvent capable of reactivating the pattern printed on the base film surface can be used, and pigments, plasticizers, etc. can also be appropriately added. curing agent, etc. For example, what mixed a pigment, a plasticizer, butyl cellulose acetate, and butyl carbitol acetate with butyl methacrylate can be used. Moreover, the coating method using a gravure roll and a sprayer is mentioned as a coating method of the said active agent.

In addition, the above-mentioned process of coating the active agent on the pattern printing surface can be carried out before making the base film float on the liquid surface, and can also be carried out after making the base film float on the liquid surface. It is not particularly limited if it is performed before pressing the transfer material upward.

In addition, in addition to the hydraulic transfer method of the above-mentioned continuous method and batch method, the following hydraulic transfer method (3) can be mentioned.

That is, the following hydraulic transfer method can be mentioned: After printing a predetermined pattern in a dry state on the surface of the base film obtained above, coating an active energy ray-curable film containing a photopolymerizable monomer such as a solvent-free ultraviolet ray or an electron ray. The resin composition wets the pattern in the above-mentioned dry state. Then, the base film is floated on the water surface with the wet pattern printing surface above, and the object to be transferred is pressed from above the base film to transfer the pattern printed on the surface of the base film to the surface of the object to be transferred. Next, the pattern transferred on the transfer object is fixed by irradiating active energy rays such as ultraviolet rays or electron beams to the transfer object on which the pattern is transferred to cure the curable resin composition.

Moreover, as another hydraulic pressure transfer method, the hydraulic pressure transfer method (4) mentioned below is mentioned.

That is, the following hydraulic transfer method can be cited: preparing a hydrophobic transfer layer (pattern) soluble in an organic solvent on the surface of the base film obtained as above, and preferably further laminating a releasable pattern on the transfer layer. Transfer film obtained by peeling off the film. Next, after peeling off the peeling film, the base film is positioned below to float on the water surface, and an activator is applied to the transfer layer to activate the transfer layer. Next, the material to be transferred is pressed against the transfer layer, the transfer layer is transferred onto the surface of the material to be transferred, and the base film is then removed. Next, at least one of active energy ray irradiation and heating, such as ultraviolet rays or electron rays, is applied to the object to be transferred on which the transfer layer (pattern) is transferred, thereby curing the transfer layer (pattern) and transferring the transfer layer (pattern). The pattern imprinted on the object to be transferred is fixed.

Here, as the above-mentioned organic solvent, for example: toluene, xylene, carbitol, carbitol acetate, butyl carbitol acetate, butyl cellulose, cellulose acetate, butyl cellulose acetate esters, methyl isobutyl ketone, ethyl acetate, 3-methyl-3-methoxybutyl acetate, etc., and mixtures thereof.

Here, the transfer layer preferably has a curable resin layer, and more preferably includes a curable resin layer provided on the base film and a decorative layer having a printing ink film or a paint film provided on the curable resin layer.

In addition, the curable resin layer is preferably made of urethane (meth)acrylate having 3 or more (meth)acryloyl groups in one molecule, polyester (meth)acrylate having 3 or more (meth)acryloyl groups in one molecule. group) acrylate and an active energy ray-curable resin in epoxy (meth)acrylate having three or more (meth)acryloyl groups in one molecule.

When the base film for hydraulic transfer printing of the present invention is used in the hydraulic transfer printing method described above, especially in the hydraulic transfer printing method (4), it not only has a film strength that can withstand hydraulic transfer printing, but also has The hydrophobic curable resin layer can also exert the effect of being excellent in dissolution or dispersibility of the base film.

In addition, when irradiating the above-mentioned active energy rays, for example, in the case of ultraviolet rays, a conventionally known ultraviolet irradiation device equipped with a light source lamp such as a high-pressure mercury lamp or a metal halide lamp and an irradiator (light source) can be used.

In addition, in the case of curing by irradiating active energy rays, it is preferable to mix a photopolymerization initiator that absorbs light such as ultraviolet rays to initiate a polymerization reaction. For example, diethoxyacetophenone, Acetophenone compounds such as 1-hydroxycyclohexyl-phenyl ketone; Benzophenone compounds such as benzophenone and o-benzoylbenzoic acid methyl-4-phenylbenzophenone; Benzoin, benzoin Benzoin compounds such as isopropyl ether; acylphosphine oxide compounds; thioxanthone compounds; aminobenzophenone compounds; polyether maleimide carboxylate compounds, etc. These compounds can also be used in combination.

In the above-mentioned curable resin composition, in addition to the photopolymerization initiator, photopolymerizable monomers, sensitizers, fillers, inert organic polymers, leveling agents, thixotropy imparting agents, thermal Additives such as polymerization inhibitors.

In the present invention, the pattern printed on the surface of the base film can be transferred to the object to be transferred by the hydraulic transfer printing method through the above steps. In addition, the above-mentioned pattern printed on the surface of the base film is not particularly limited, and any pattern may be used as long as it is a printable pattern such as wood grain, various patterns, images, and the like.

The material of the object to be transferred in the hydraulic transfer printing method of the present invention is not particularly limited, and for example, an inorganic molded body such as a plastic molded body, a metal molded body, a wood molded body, and glass can be used. In addition, the shape is not particularly limited either, and may be flat or have various three-dimensional shapes.

Example

Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to the following Example in the range which does not deviate from the summary.

In addition, unless otherwise specified, "%" in an example means a weight basis.

[Example 1]

<Preparation of base film>

Make the viscosity (20 ℃) of 85 parts of 4 weight % aqueous solution be 18 mPa s, the average degree of saponification is the PVA (A1) of 88 mol %, the average viscosity (20 ℃) of 15 parts 4 weight % aqueous solutions is 5 mPa s, average PVA (A2) with a saponification degree of 88 mol%, 2 parts of glycerin, 6 parts of starch, and 1.2 parts of surfactant (polyoxyethylene sorbitan monolaurate) were dissolved in water to prepare 18% (solid content concentration) aqueous dispersion (concentrate). This dope is discharged from the T-die onto a rotating stainless steel endless belt whose surface temperature is adjusted to 80°C, cast at a speed of 10 m/min to form a film, and then heat-treated with a heat roller adjusted to 80°C , and a PVA film with a thickness of 30 μm was obtained, which was used as a base film for hydraulic transfer.

<Preparation of Curable Resin Composition>

60 parts (mass average molecular weight) of the average six-functional urethane acrylate (UA1) obtained by reacting 2 molar equivalents of pentaerythritol, 7 molar equivalents of hexamethylene diisocyanate and 6 molar equivalents of hydroxyethyl methacrylate at 60°C 890), 40 parts of acrylic resin "Paraloid A-11" (Tg100°C, mass average molecular weight 125,000) manufactured by Rohm and Haas, a mixed solvent of ethyl acetate and methyl ethyl ketone (mixing weight ratio 1/1), the preparation of solid component 42 % curable resin composition.

<Preparation of Decorative Film (I)>

A 50-μm-thick unstretched polypropylene film (hereinafter referred to as PP film) manufactured by Toyobo Co., Ltd. was used as a release film, and a 3-μm-thick polyurethane ink (trade name: ユニビア A) was printed on the film with a four-color gravure printing machine. The wood grain pattern of preparation decorative film (I).

<Preparation of film (II) for hydraulic transfer>

The above-mentioned curable resin composition was coated on the film-forming tape side of the above-mentioned base film with a lip coater so that the film thickness after drying was 20 μm, and then dried at 60° C. for 2 minutes to prepare a tape. There is the base film of curable resin composition layer, then the uniaxially stretched polypropylene film (hereinafter referred to as OPP film) that the curable resin composition layer of this film and Toyobo Co., Ltd. manufactures is laminated at 60 ℃, The laminated film was directly wound up to prepare a film (II) for hydraulic transfer.

<Preparation of film (III) for hydraulic transfer>

After peeling the OPP film from the hydraulic transfer film (II), the curable resin composition layer and the ink layer of the decorative film (I) are laminated at 60°C, and then directly wound and laminated again. Film, Preparation of Film for Hydraulic Transfer (III).

In addition, when the obtained film (III) for hydraulic pressure transfer was used, the PP film was peeled off, and at that time, the ink layer was transferred to the curable resin composition layer on the side of the PVA film without defects.

The obtained film for hydraulic transfer (III) was evaluated as follows.

<Evaluation method>

After the hydraulic transfer film (III) obtained above was cut into a size of 3 cm x 5 cm, the PP film was peeled off, and the PVA film side was fixed on a jig capable of fixing the film parallel to the water surface. Next, add water (1 liter) to a 1 liter beaker, keep the water temperature at 30°C while stirring with a stirrer, and immerse the sample in water so that the fixed height of the sample is at the 600cc mark position, using a 3cm stirring bar While continuing stirring at a speed of 400 rpm, the dissolution of the PVA film on the lower side was confirmed.

The confirmation method is: take out the sample from the water after the predetermined time has elapsed, touch the surface of the PVA film, check whether there is mucus, and evaluate according to the following criteria.

◯: Mucus disappeared in less than 5 minutes.

×: Mucus does not disappear even after 5 minutes.

[Examples 2-4, Comparative Examples 1-3]

Except having changed the composition of the PVA resin as shown in Table 1, it carried out similarly to Example 1, the PVA film of thickness 30 micrometers was obtained, and this was used as the base film for hydraulic transfer.

Table 1 shows the evaluation results of Examples and Comparative Examples.

Table 1

From the above results, it can be seen that for the example in which two predetermined PVAs were used in combination as the PVA-based resin, although one side was covered with a hydrophobic curable resin composition layer, the solubility or dispersibility was still excellent. In Comparative Example 1, which uses only one type of PVA used in the conventional base film with PVA having a small molecular weight, sufficient solubility or dispersibility cannot be obtained, and when two types of PVA are used together, if any of the viscosity ranges of the two types of PVA Outside the scope of the present invention, the solubility or dispersibility is poor. This is presumed to be because, by adding a small amount of PVA (A2) to PVA (A1), PVA (A1) becomes easily decomposed and dissolves or disperses easily, and when there is only existing PVA (A1), PVA swells and forms mucus, making it easier to dissolve or disperse. residual.

As mentioned above, although this invention was concretely demonstrated with reference to the specific embodiment, it is clear to those skilled in the art that various changes and modifications can be added without deviating from the mind and range of this invention.

This application is based on the Japanese patent application (Japanese Patent Application No. 2008-307748) of an application on December 2, 2008, and the content is taken in here as a reference.

Industrial Utilization Possibility

The base film for hydraulic transfer printing of the present invention can be widely used in hydraulic transfer printing of interior and exterior decorations of automobiles, exterior decoration of mobile phones, various electrical products, building materials, households, daily necessities, and the like.

Claims (7)

1. basal membrane for hydraulic transfer printing; Contain the polyvinyl alcohol film; It is characterized in that; Said polyvinyl alcohol film contains polyvinyl alcohol resin, said polyvinyl alcohol resin contain under 20 ℃, 4 weight % viscosity in aqueous solution be the polyvinyl alcohol resin A1 of 15～50mPas and under 20 ℃, 4 weight % viscosity in aqueous solution are the polyvinyl alcohol resin A2 of 1～10mPas.

2. basal membrane for hydraulic transfer printing as claimed in claim 1 is characterized in that, polyvinyl alcohol resin A2 under 20 ℃, 4 weight % viscosity in aqueous solution than polyvinyl alcohol resin A1 under 20 ℃, 4 weight % viscosity in aqueous solution are little by 5～50%.

3. basal membrane for hydraulic transfer printing as claimed in claim 1 is characterized in that, the use level of polyvinyl alcohol resin A2 is 10～50 weight portions with respect to the polyvinyl alcohol resin A1 of 100 weight portions.

4. basal membrane for hydraulic transfer printing as claimed in claim 1 is characterized in that, the average saponification degree of polyvinyl alcohol resin A1 is 70～98 moles of %, and the average saponification degree of polyvinyl alcohol resin A2 is 70～98 moles of %.

5. basal membrane for hydraulic transfer printing as claimed in claim 1 is characterized in that, the difference of the average saponification degree of polyvinyl alcohol resin A1 and the average saponification degree of polyvinyl alcohol resin A2 is 3 moles below the %.

6. basal membrane for hydraulic transfer printing as claimed in claim 1 is characterized in that, the thickness of polyvinyl alcohol film is 20～50 μ m.

7. like each described basal membrane for hydraulic transfer printing in the claim 1～6, be used for liquid pressure transfer method, in the said liquid pressure transfer method; Form in membrane surface and to dissolve in the hydrophobicity transfer printing layer of organic solvent, and then make basement membrane be positioned at the below and float on the surface, after the coating activating agent makes above-mentioned transfer printing layer activation on the above-mentioned transfer printing layer; To be transferred thing by being pressed on the above-mentioned transfer printing layer, and transfer printing layer will be transferred to be transferred the thing surface, remove basement membrane then; Then; The thing that is transferred through transfer printing there being above-mentioned transfer printing layer is implemented the active energy beam irradiation and is added pine at least a, and transfer printing layer is solidified, and fixes thereby will be transferred to the pattern that is transferred on the thing.