JP2009101691A - Method for manufacturing of water-soluble base film for transfer printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-soluble base film to be used for a transfer printing film that can transfer print in highly fine design. <P>SOLUTION: The method for manufacturing of the water-soluble base film for transfer printing referred in this invention is characterized by obtaining a film which employs polyvinyl alcohol resin as its principal component and contains a crosslinking agent heat-treated at a temperature of 100-160 degrees C, and, has, when measured by a differential scanning calorimetry (DSC), two endoergic peaks over 150 degrees C or more in the endoergic curve of the first Run when temperature is raised to -30 to 260 degrees C with the raising temperature speed of 10 degrees C/minute and, at the same time, is of its peak temperature gradient to be less than 32 degrees C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a water-soluble base film for transfer printing capable of smoothly giving a high-definition design to a transfer target having a three-dimensional surface such as a non-planar shape.

  Conventionally, as a method of printing a design on a three-dimensional structure, a multilayer film having a printing layer on one side of a water-soluble base film is applied to the printing layer by applying an activation liquid such as a solvent. There is known a method in which the printed layer is floated on the water surface in an activated state, floated on the surface of the water, and the design of the printed layer is transferred to the three-dimensional structure by pushing the transferred material from above.

  In this case, such a base film becomes a gel film layer when it floats on the water surface, and it is required to wrap around the transfer material without causing wrinkles or wrapping. Polyvinyl alcohol is used as a material for such a base film. A resin film is used, and a thin film for transfer printing using such a polyvinyl alcohol resin as a base film has been proposed.

  As a thin film for transfer printing, the present applicant also disclosed in Patent Document 1 an ultrahigh polymerization degree polyvinyl alcohol resin having an average polymerization degree of 3200 or more and an average saponification degree of 65 to 95 mol%, an average polymerization degree of less than 3200, and an average It consists of a composition in which a polyvinyl alcohol resin having a degree of conversion of 65 to 95 mol% is mixed at a weight ratio of 30:70 to 70:30, and proposes a film having a thickness of 35 μm or less. It consists of a composition in which 2 to 15 parts by weight of a natural gum-based viscous material such as mannan, xanthan gum, guar gum, etc. is mixed with 100 parts by weight of a polyvinyl alcohol-based resin, the thickness is 1 to 50 μm, and the swelling elongation rate on the water surface is A film of 1.35 times or less was proposed.

Furthermore, in Patent Document 3, a film is formed from a polyvinyl alcohol-based resin having an average degree of polymerization of 300 to 3000 and an average degree of saponification of 65 to 97 mol%, and 0.02 to 10% by weight of boric acid or We proposed a thin film for transfer printing containing the salt and having a thickness of 0.01 to 0.1 mm.
Japanese Patent Laid-Open No. 7-117327 Japanese Unexamined Patent Publication No. 7-117328 Japanese Patent Publication No.61-3277

  However, although the thin film disclosed in Patent Document 1 can be transferred at a high speed, it is easy to produce swelling spots because polyvinyl alcohol having a different degree of polymerization is blended. Accordingly, the design printed on the base film may be different from the design transferred and printed on the adherend, and the thin film disclosed in Patent Document 2 uses natural rubber. In particular, there is a problem that accuracy is partially lowered or reproducibility is low, and the thin film disclosed in Patent Document 3 is also on the base film with the recent high definition of design. The design printed on the substrate and the design transferred and printed on the adherend may be different images, and a water-soluble base film for printing capable of reliably transferring a high-definition design is desired.

  Therefore, as a result of intensive studies in view of the present situation, the present inventor conducted a heat treatment at a temperature of 100 to 160 ° C. by performing a heat treatment on a film containing a polyvinyl alcohol resin as a main component and further containing a crosslinking agent. Having two endothermic peaks at 150 ° C. or higher in the 1st Run endothermic curve measured with a scanning calorimeter (DSC) at a temperature rising rate of 10 ° C./min to −30 to 260 ° C. And the water-soluble base film for transfer printing whose peak temperature difference is less than 32 degreeC was obtained, and it discovered that the transfer of a high definition design was possible by using this film, and came to complete this invention.

  The high-definition design referred to in the present invention is a complex design using a plurality of colors (for example, a leopard pattern, a wood grain pattern, etc.), and the design before transfer is printed on the transferred material with high accuracy. The conventional base film can be transferred, but the image after transfer is more blurred than the original design, and is not clear.In the present invention, such a high-definition design is required. It became possible to transfer.

  Since the water-soluble base film for transfer printing obtained by the method of the present invention has a specific endothermic peak as measured by a differential scanning calorimeter (DSC), the film for transfer printing using such a film has high definition. Design transfer printing can be performed.

  The present invention is described in detail below.

The water-soluble base film for transfer printing obtained by the method of the present invention (hereinafter sometimes simply referred to as a base film) is mainly composed of a polyvinyl alcohol resin, and such a polyvinyl alcohol resin is particularly limited. However, it can be produced by a known method.
That is, it is obtained by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester compound.

  As such vinyl ester compounds, vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, vinyl stearate, etc. alone or Although used in combination, vinyl acetate is preferred for practical use.

  Further, in the present invention, other monomers can be copolymerized within a range not impairing the object of the present invention. Examples of such monomers include ethylene, propylene, isobutylene, α-octene, α -Olefins such as dodecene, α-octadecene, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid or salts thereof, mono- or dialkyl esters, acrylonitrile, methacrylonitrile, etc. Nitriles, amides such as acrylamide and methacrylamide, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid or salts thereof, alkyl vinyl ethers, N-acrylamidomethyltrimethylammonium chloride, allyltrimethyla Polyoxyalkylene (meth) allyl such as monium chloride, dimethyldiallylammonium chloride, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether Polyoxyalkylene (meth) such as ether, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, etc., polyoxyalkylene (meth) acrylate such as polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, etc. Acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene Vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, and the like polyoxypropylene vinyl amine may.

  In carrying out the polymerization (or copolymerization), there is no particular limitation and a known polymerization method is arbitrarily used. Usually, solution polymerization using an alcohol such as methanol, ethanol or isopropyl alcohol as a solvent is carried out. Of course, emulsion polymerization and suspension polymerization are also possible.

  The polymerization reaction is carried out using a known radical polymerization catalyst such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, and the reaction temperature is from 35 ° C. to the boiling point (more preferably from 50 to 80). C)).

  When the obtained vinyl ester polymer is saponified, the polymer is dissolved in alcohol and the reaction is carried out in the presence of an alkali catalyst. Examples of the alcohol include methanol, ethanol, butanol and the like. The concentration of the copolymer in the alcohol is selected from the range of 20 to 50% by weight.

  As the saponification catalyst, alkali catalysts such as alkali metal hydroxides and alcoholates such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate and potassium methylate can be used. What is necessary is just to make the usage-amount of this catalyst 1-100 millimol equivalent with respect to vinyl ester. In some cases, saponification with an acid catalyst is also possible.

Thus, a polyvinyl alcohol resin can be obtained. In the present invention, the polyvinyl alcohol resin has a 4% by weight aqueous solution viscosity of 2 to 60 mPa · s (20 ° C.) and a saponification degree of 65 to 97 mol%. Is preferably used.
That is, when the viscosity of the 4% by weight aqueous solution is less than 2 mPa · s (20 ° C.), the film strength when printing the design (pattern) on the base film may be insufficient, and printing spots may occur. If the temperature exceeds s (20 ° C), the adhesiveness between the transferred material and the transfer printing film (the base film on which the design is printed) may be reduced during transfer to the transferred material, and wrinkles or peeling may occur. It is not preferable. The more preferable range of the viscosity of the 4% by weight aqueous solution is 10 to 60 mPa · s (20 ° C.).

  On the other hand, when the degree of saponification is less than 65 mol% or exceeds 97 mol%, it may take a long time to dissolve the base film after transfer. A more preferable range of the saponification degree is 72 to 95 mol%.

  The base film obtained by the method of the present invention is mainly composed of the polyvinyl alcohol-based resin as described above, and further contains a cross-linking agent described later, and the resin is formed into a base film. However, in the present invention, the base film has two endothermic peaks at 150 ° C. or higher in an endothermic curve measured by a differential scanning calorimeter (DSC), and the peak temperature difference is within 32 ° C. It is necessary to satisfy this condition, and the object of the present invention can be achieved.

  In addition, the endothermic curve measured with a differential scanning calorimeter (DSC) here is a curve as shown in FIG. 1, specifically, up to −30 to 260 ° C. at a heating rate of 10 ° C./min. The endothermic curve of the first run when the temperature is raised can be measured using, for example, “DSC-7” manufactured by PerkinElmer, Inc. The measurement sample (film) at this time is diphosphorus pentoxide After drying for 4 days (at room temperature) in a desiccator containing, 7 ± 1 mg may be collected and measured.

  In order to obtain a base film satisfying such conditions, (1) a method of forming a film by blending a polyvinyl alcohol resin with a crosslinking agent, and then performing a specific heat treatment, (2) a degree of polymerization with the same degree of polymerization A method of blending different polyvinyl alcohol resins may be mentioned, but industrially, the method (1) is preferable, and this method will be described more specifically.

  The crosslinking agent to be blended with the polyvinyl alcohol resin is not particularly limited as long as it causes a crosslinking reaction with the polyvinyl alcohol resin, and examples thereof include boron compounds and inorganic salts. Acid, calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), aluminum borate / potassium borate, ammonium borate (ammonium metaborate, ammonium tetraborate, ammonium pentaborate, eight Ammonium borate), cadmium borate (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 (boric acid Copper, copper metaborate, copper tetraborate, etc.), sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.), boric acid Lead (lead metaborate, 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, five lithium borate) other such as borax, car Knight, In'yoaito, island stone, Suian stone, and the like borate minerals such Zaiberi stone.

Examples of inorganic salts include (NH ₄ ) ₂ SO ₄ , Na ₂ SO ₄ , K ₂ SO ₄ , ZuSO ₄ , CuSO ₄ , FeSO ₄ , MgSO ₄ , Al ₂ (SO ₄ ) ₃ , KAl (SO ₄ ). ₂ , NH ₄ NO ₃ , NaNO ₃ , KNO ₃ , Al (NO ₃ ) ₃ , NH ₄ Cl, NaCl, KCl, MgCl ₂ , CaCl ₂ , Na ₃ PO ₄ , K ₂ CrO ₄ , K ₃ C ₆ H ₅ O ₇ etc. are mentioned.

Among the above crosslinking agents, borax and K ₃ C ₆ H ₅ O ₇ (potassium citrate) are preferably used.

  The amount of the crosslinking agent blended in the polyvinyl alcohol resin is 0.1 to 10 parts by weight (more preferably 0.5 to 5 parts by weight, particularly 0.5 to 3 parts per 100 parts by weight of the polyvinyl alcohol resin. If the amount is less than 0.1 parts by weight, it is difficult to satisfy the above condition. Conversely, if the amount exceeds 10 parts by weight, the above condition can be satisfied. The adhesion between the adherend and the base film on which the design is printed at the time of transfer to the adherend is liable to cause wrinkles and peeling, which is not preferable.

  Next, a polyvinyl alcohol resin blended with a cross-linking agent is formed into a base film, and the film formation is not particularly limited. Polyvinyl alcohol film to be a base film by a method of casting on a smooth metal surface such as an endless belt, a method of adding water or a plasticizer described later to the resin as appropriate, and melt-molding by means such as an extrusion method, etc. Can be obtained.

Further, at the time of production, a plasticizer (glycerin, diglycerin, triethylene glycol, polyethylene glycol, polypropylene glycol, etc.), a surfactant (polyoxyethylene nonylphenyl ether, Polyoxyethylene octyl nonyl ether, polyoxyethylene dodecylfinil ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan mono Oleate, polyoxyalkylene alkyl ether phosphate monoethanolamine salt, polyoxyethylene lauryl amino ether, polyoxyethylene Stearylamino ether), antioxidants (phenolic, amine-based, etc.), stabilizers (phosphate esters, etc.), colorants, fragrances, extenders, anti-packaging agents, rust inhibitors, UV absorbers, inorganic powders , Surfactants, and other water-soluble polymers (sodium acrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethylcellulose, starch, etc.) may be added.
Furthermore, you may mix and use 2 or more types of polyvinyl alcohol-type resin as needed.

  The film thickness of the polyvinyl alcohol film is not particularly limited, but is preferably 10 to 50 μm (more preferably 15 to 50 μm, particularly 15 to 45 μm). If the film thickness is less than 10 μm, the base film has a design. There is a risk that printing spots may occur due to insufficient film strength when printing, and conversely, if it exceeds 50 μm, the adhesion between the transferred material and the transfer printing film will be reduced during transfer to the transferred material. Peeling may occur, which is not preferable.

The obtained base film is finally subjected to a heat treatment to become a base film satisfying the conditions defined in the present invention.
In this heat treatment, heat treatment is performed at 100 to 160 ° C. (further, 105 to 140 ° C.). When the temperature is less than 100 ° C., it becomes difficult to satisfy the above conditions, and conversely, the temperature exceeds 160 ° C. Further, the crystallinity of the base film is excessively increased, and the water solubility after transfer is undesirably lowered.

  There is no restriction | limiting in particular as the method of this heat processing, For example, it is possible to heat-process by methods, such as a hot roll (a calender roll is included), a hot air, a far infrared ray, and dielectric heating.

The base film satisfying the conditions defined in the present invention thus obtained has a transfer design printed on its surface and is put to practical use as a transfer printing film.
Examples of such a design include an arbitrary pattern such as a wood grain pattern, a marble pattern, a geometric pattern, an elephant pattern, an abstract pattern, and a character. These designs are preferably formed by printing an ink obtained by adding a colorant such as a dye or a pigment to a water-insoluble resin binder. Examples of the water-insoluble resin include a mixture of nitrified cotton and alkyd resin.

Hereinafter, the present invention will be described in more detail with reference to examples.
Unless otherwise specified in the examples, “%” and “parts” are based on weight.

Example 1
Polyvinyl alcohol-based resin [4% aqueous solution viscosity 30 mPa · s, average saponification degree 88.0 mol%] An aqueous solution having a solid content of 20% consisting of 100 parts and 5 parts of potassium citrate is heated to a temperature of 95 by drum casting film forming method. A polyvinyl alcohol film was obtained under the condition of ° C., and the film was heat-treated at 125 ° C. for 10 minutes to obtain a base film having a thickness of 40 μm.
When the endothermic curve of this film was measured by the method in the text, the chart shown in FIG. 1 was obtained, and there were two endothermic peaks at 189 ° C. and 210 ° C., and the temperature difference was 21 ° C.

Next, using the gravure ink [pigment (quinacridone) / alkyd resin / toluene / ethyl acetate / isopropyl alcohol = 10/20/25/30/15 (weight ratio)] on the obtained base film, gravure printing method [80 lines / inch, pitch: 317 μm, bank: 217 μm] was used to print a dot pattern to produce a transfer printing film.
Separately, a vinyl chloride plate (100 mm × 100 mm × 2 mm) is prepared as a transfer target, and a primer [toluene / ethyl acetate / isopropyl alcohol = 2/3/3 (weight ratio) is mixed on the transfer (printing) surface. A solution coated with [Solution] was prepared.

The transfer printing film (400 mm × 400 mm) is floated in a water bath containing 30 ° C. water, and after 60 seconds, the vinyl chloride plate is pressed to transfer the dot pattern to the surface of the vinyl chloride plate. The base film was removed by spraying water at 30 ° C. and dried at 40 ° C. for 20 minutes to obtain a vinyl chloride plate on which the dot pattern was transferred and printed.
When the dot pattern (the central part in the range of 10 mm × 10 mm) transferred to the obtained vinyl chloride plate was observed with an optical microscope, the average distance between the dots was 428 μm in the longitudinal direction of the base film and 454 μm in the width direction. The variation (standard deviation) was 5.0 in the longitudinal direction and 5.3 in the width direction.

Example 2
In Example 1, a base film was obtained in the same manner as in Example 1 except that 0.7 part of borax was used instead of potassium citrate and the heat treatment condition was changed to 130 ° C. for 3 minutes.
The obtained base film had two endothermic peaks at 183 ° C. and 210 ° C., and the temperature difference was 27 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 419 μm in the longitudinal direction of the base film and 463 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 4.9 in the direction and 5.4 in the width direction.

Example 3
In Example 2, a base film was obtained in the same manner except that the heat treatment conditions were changed to 140 ° C. for 1 minute, and evaluation was performed in the same manner.
The obtained base film had two endothermic peaks at 185 ° C. and 211 ° C., and the temperature difference was 26 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 423 μm in the longitudinal direction of the base film and 459 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 4.9 in the direction and 5.4 in the width direction.

Example 4
In Example 2, a base film was obtained in the same manner except that the heat treatment conditions were changed to 115 ° C. for 10 minutes, and evaluation was performed in the same manner.
The obtained base film had two endothermic peaks at 179 ° C. and 209 ° C., and the temperature difference was 30 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 433 μm in the longitudinal direction of the base film and 469 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 7.4 in the direction and 8.0 in the width direction.

Example 5
A base film was obtained in the same manner as in Example 1 except that the heat treatment was performed at 115 ° C. for 10 minutes, and evaluation was performed in the same manner.
The obtained base film had two endothermic peaks at 182 ° C. and 209 ° C., and the temperature difference was 27 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 432 μm in the longitudinal direction of the base film and 450 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 5.0 in the direction and 5.2 in the width direction.

Example 6
In Example 2, a base film was obtained in the same manner except that polyvinyl alcohol having a 4% aqueous solution viscosity of 15 mPa · s and an average saponification degree of 95 mol% was obtained as the polyvinyl alcohol-based resin. went.
The obtained base film had two endothermic peaks at 183 ° C. and 210 ° C., and the temperature difference was 27 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 414 μm in the longitudinal direction of the base film and 467 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 4.8 in the direction and 5.5 in the width direction.

Example 7
In Example 2, a base film was obtained in the same manner except that polyvinyl alcohol having a 4% aqueous solution viscosity of 35 mPa · s and an average saponification degree of 80 mol% was obtained as a polyvinyl alcohol-based resin. went.
The obtained base film had two endothermic peaks at 187 ° C. and 210 ° C., and the temperature difference was 23 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 421 μm in the longitudinal direction of the base film and 447 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 4.4 in the direction and 4.6 in the width direction.

Example 8
In Example 2, a base film was obtained in the same manner except that the amount of borax mixed was 1.2 parts, and evaluation was performed in the same manner.
The obtained base film had two endothermic peaks at 185 ° C. and 211 ° C., and the temperature difference was 26 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 420 μm in the longitudinal direction of the base film and 437 μm in the width direction, and the variation (standard deviation) was longitudinal. It was 4.6 in the direction and 4.8 in the width direction.

Comparative Example 1
In Example 1, a base film was obtained in the same manner except that no heat treatment was performed, and evaluation was performed in the same manner.
The obtained base film had two endothermic peaks at 172 ° C. and 209 ° C., and the temperature difference was 37 ° C.
When the transferred dot pattern was observed with an optical microscope in the same manner as in Example 1, the average distance between the dots was 469 μm in the longitudinal direction of the base film and 508 μm in the width direction, and the variation (standard deviation) was also in the longitudinal direction. 8.4 in the width direction and 9.1 in the width direction, which were larger than those in the above examples.

Endothermic curve measured with a differential scanning calorimeter (DSC) of the base film obtained by the method of the present invention.

Claims (4)

  A film comprising a polyvinyl alcohol-based resin as a main component and further containing a crosslinking agent is heat-treated at a temperature of 100 to 160 ° C., and measured by a differential scanning calorimeter (DSC). In the first run endothermic curve when the temperature is raised to -30 to 260 ° C, a film having two endothermic peaks at 150 ° C or more and a peak temperature difference of 32 ° C or less is obtained. A method for producing a water-soluble base film for transfer printing.   The water-soluble base for transfer printing according to claim 1, wherein the polyvinyl alcohol resin has an average saponification degree of 65 to 97 mol% and a 4 wt% aqueous solution viscosity (20 ° C) of 2 to 60 mPa · s. A method for producing a film.   The method for producing a water-soluble base film for transfer printing according to claim 1, wherein the crosslinking agent is either borax or potassium citrate.   The method for producing a water-soluble base film for transfer printing according to any one of claims 1 to 3, wherein the film has a thickness of 10 to 50 µm.

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