JP4233693B2 - How to make decorative paper - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing decorative paper used for the production of interior building materials, furniture and the like.
[0002]
[Prior art]
Conventionally, surface decoration materials called PVC doubling and wiping coats have been widely used as decorative materials for house interior materials and furniture, but in recent years, without using PVC that may cause environmental pollution. What was made is now required.
[0003]
The decorative paper for the manufacture of surface cosmetics that does not use PVC is made of polyethylene film, polypropylene film, or other materials that are printed on chlorine-free plastic film, and original paper that is made of pulp-based special paper. Some have a coating for printing and surface protection.
[0004]
The latter is superior to the former in adhesion suitability, scratch resistance, light resistance, weather resistance, etc., but since the original fabric is less stretched, for example, in applications where the decorative material is subjected to bending processing such as V-cut processing. It is often easy to tear and difficult to use.
[0005]
[Problems to be solved by the invention]
Therefore, the present invention is used for manufacturing a decorative material that is subjected to bending processing such as V-cut processing, although it is a decorative paper made of paper and has a larger elongation and a higher breaking strength than this type of decorative paper. It is intended to provide a possible paper-based decorative paper and a method for producing the same.
[0006]
[Means for Solving the Problems]
The decorative paper manufacturing method of the present invention that has achieved the above object is to print on a base paper impregnated with a mixture of a thermoplastic resin and a thermosetting resin, and provide a coating for forming a transparent surface protective layer on the printed surface. When the decorative paper is produced by coating, the coating for forming the surface protective layer is first performed using a polyurethane-based water-based resin paint, and then using an oil-based polyurethane-based resin paint.
[0007]
In a preferred embodiment of the present invention, an aqueous thermoplastic resin dispersion selected from the group consisting of an acrylic resin emulsion, a synthetic rubber latex, a water-soluble acrylic resin solution, an aqueous polyurethane dispersion and the like, an aqueous epoxy resin, an aqueous dispersion isocyanate, and the like The impregnated paper formed by impregnating the base paper with a mixture of a thermosetting resin prepolymer selected from the group consisting of printing and coating for forming a surface protective layer is performed.
[0008]
In this case, the preferred combination ratio of the thermoplastic resin and the thermosetting resin is 50:50 to 95: 5.
[0009]
The coating of the water-based urethane resin paint is desirably performed by a gravure printing method using the paint whose viscosity is adjusted to 300 to 1000 cp.
[0010]
The present invention also provides a uniform distribution of the wear resistance improving material on the decorative paper by mixing the wear resistance improving material made of fine powdered aluminum oxide into the polyurethane-based water-based resin paint in the production method of the present invention. Provided is a method for producing a reinforced decorative paper.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
First, the resin-impregnated paper for producing decorative paper of the present invention will be described. As a base paper for the production of impregnated paper, paper having a basis weight of about 30 to 80 g / m ² which is made without using a sizing agent is used in principle. Among them, those having a density of 0.7 g / cm ³ or less, an air permeability (JIS P-8117) of 10 seconds / 100 cc or less, and a water absorption (JIS P-8141) of 50 mm / 10 minutes or more are used for inter-paper reinforcement. It is preferable because the impregnation property of the resin liquid is good.
[0012]
As the resin liquid impregnated into the base paper, a mixed resin liquid of a thermoplastic resin and a thermosetting resin is used for the reason described later.
[0013]
In that case, as the thermoplastic resin, acrylic ester homopolymer emulsion or vinyl acetate, copolymer emulsion with styrene, latex of synthetic rubber such as styrene butadiene copolymer, water-soluble acrylic resin solution, polyurethane aqueous A dispersion or the like is preferred. In addition to prepolymers such as melamine resins, urea resins, and phenol resins, water-borne epoxy resins, water-dispersible modified polyisocyanates, and the like can be used as thermosetting resins. Both thermoplastic resin and thermosetting resin may be used in combination of two or more components.
[0014]
The resin solution for impregnation is prepared by mixing the above thermoplastic resin and thermosetting resin so that the solids ratio is 50:50 to 95: 5. Desirable to do. The impregnation of the prepared resin liquid can be carried out by a conventional method, but so that the resin uniformly penetrates into the paper layer and about 30 to 40% by weight of the total weight of the impregnated paper becomes a resin solid. It is desirable to do.
[0015]
Thereafter, the impregnated paper is obtained by heating and drying by a conventional method. However, if shrinkage in the width direction is caused by performing the drying process while applying tension in the length direction of the base paper, the elongation in the width direction of the decorative paper is increased. The bending workability can be improved.
[0016]
Impregnated paper impregnated with a mixed resin solution of a thermoplastic resin and a thermosetting resin is excellent in flexibility and dimensional stability during printing, and particularly has good V-cut processability when finished on a decorative board. give.
[0017]
If necessary, this impregnated paper is coated with a coating for improving printability, smoothing, improving adhesion suitability, strengthening of the decorative layer, etc., in the same manner as the impregnated resin, prior to printing and surface coating described in detail below. You may give using resin.
[0018]
Printing on the impregnated paper can be performed with an arbitrary number of printings, for example, using nitrocellulose-based printing ink in exactly the same manner as in general decorative paper production.
[0019]
A coating for forming a transparent surface protective layer is overprinted at least twice on the printing surface of the impregnated paper after printing. The initial coating is performed using a polyurethane-based water-based resin paint capable of forming a transparent resin layer. As the polyurethane-based water-based resin paint, any commercially available product can be used. Preferred examples thereof include an aqueous dispersion of water-dispersible polyurethane (polyester-based, polyether-based, polycarbonate-based, etc.) or crosslinked to this. And the like, and those obtained by mixing a water-dispersible isocyanate with an aqueous dispersion of polyester polypol or acrylic polyol.
[0020]
The water-based urethane resin paint has a good leveling property, and since it uses water as a medium, it is difficult to cause a change in viscosity due to solvent evaporation. Therefore, if it is a normal oil-based resin paint, it is difficult to apply by a gravure printing method to 300 to 1000 cp. Even a high-viscosity product (and therefore a high solid matter concentration) can be uniformly applied using a gravure printing machine, and a thick coating can be formed by a single application.
[0021]
To this water-based resin paint, a wear resistance improving material for increasing the surface strength of the decorative paper, for example, fine powder aluminum oxide may be added. At this time, if a thermosetting synthetic resin powder having a particle diameter larger than that of the wear resistance improving material is added together, wear of the gravure plate due to the hard wear resistance improving material is suppressed. This is because when the coating liquid in the gravure cell is pushed out due to the scraping force by the gravure doctor and the printing pressure from the impression cylinder through the substrate, the hard wear resistance improving material particles are pressed against the bank of the gravure plate. This is because the large resin particles prevent this. The addition of a resin powder having a large particle diameter also has the advantage that fine irregularities derived from the resin particles are produced on the surface of the product, giving a favorable feel close to that of natural wood.
[0022]
Abrasion resistance improvers can work even if they are not included in the surface protective layer of water-based urethane resin paint, but as mentioned above, water-based urethane resin paint can be coated by gravure printing method even if it has high viscosity Therefore, if a wear resistance improving material is mixed in this coating material, a high viscosity coating liquid in which the high specific gravity wear resistance improving material hardly causes sedimentation separation can be prepared, which is advantageous in terms of workability. Further, the wear resistance improving material can be uniformly distributed on the decorative paper.
[0023]
In addition to the wear resistance improving material, an optional additive such as a UV absorber for imparting weather resistance can be added to the water-based resin coating material.
[0024]
The impregnated paper coated with the polyurethane-based water-based resin paint is sent to the next process in a flexible state without fear of becoming too hard with a low moisture content in the drying process because the solvent of the paint is water. Moreover, the elongation at break is large, which is advantageous for achieving the object of the present invention.
[0025]
The same effect can be expected even when water-based resin paints other than polyurethane are used. For example, when water-based polyacrylic resin paint is used, the coating film may swell with an organic solvent or whiten with water. It tends to be inferior in solvent resistance and water resistance.
[0026]
Following the formation of the coating film with the polyurethane-based aqueous resin coating, one or more coating films are formed with the oil-based resin coating in order to adjust the surface gloss and other properties and improve the physical properties. For example, two types of polyurethane paints with different glossiness for optical emboss expression called gloss mat are applied, but these are particularly different from those for forming a surface protective layer in conventional decorative paper production. However, it can be carried out arbitrarily according to the application as long as the object of the present invention is not hindered.
[0027]
The decorative paper obtained as described above can be used in the same manner as a general decorative paper for manufacturing a decorative board using an arbitrary base material.
[0028]
【Example】
Hereinafter, the present invention will be described with reference to examples and comparative examples. The abrasion resistance in each example is based on the JAS standard A test. In order to be able to be used for the manufacture of cosmetics that undergo bending such as V-cut processing, it does not break in the 180-degree bending test, and the elongation (elongation in the width direction according to JIS P-8113) is 8% or more. It is desirable to be.
[0029]
Example 1
The following (1) to (3) are mixed to prepare an impregnating resin solution having a resin solid content of 35% by weight.
(1) Polyacrylate copolymer emulsion 45 parts Particle size 0.1 mμ, TG-20 ° C
(2) Vinyl acetate / acrylic ester emulsion 45 parts Particle size 0.1mμ, TG18 ° C
(3) Polyethylene glycidyl ether (aqueous epoxy resin) 10 parts [0030]
A 45 g / m ² no-size base paper was impregnated with the above resin, and a squeeze roll was adjusted so that 35% of the total weight after drying was impregnated resin, to obtain an impregnated paper for printing. Next, this impregnated paper was subjected to solid printing with nitrocellulose-based ink, followed by pattern printing, and then a polyurethane-based aqueous resin coating (urethane resin colloidal dispersion; viscosity 550 cp) was applied 12 g / m ^{2 by} a gravure printing method did.
[0031]
Furthermore, a mat coat layer (4 g / m ² ) made of an oil-based polyurethane resin paint containing a matting agent, and a negative plate coat of a wood grain conduit made of a polyurethane resin paint having a gloss higher than that of the mat coat layer ( 3 g / m ² ) and a low-gloss polyurethane-based resin paint were printed on the wood grain conduit, followed by curing at 70 ° C. for 48 hours to produce a so-called gloss matte decorative paper.
[0032]
The finish of the resulting decorative paper was good, and no glossy or streaky irregularities were observed as gravure inks even though a high-viscosity aqueous resin paint was used. The results of the performance test were as follows.
[0033]
Abrasion resistance: The end point (until the disappearance of the pattern 1/2) was 100 times.
Weather resistance: The end point (until discoloration, whitening, etc.) was 1000 hours in the irradiation test with Wether-O-Meter.
Water resistance: No abnormality after 1 week of immersion in water at room temperature Solvent resistance: Passed JAS thinner test Flexibility: No cracking occurred in the 180-degree bending test.
Elongation: 10%
[0034]
Comparative Example 1
A decorative paper was produced in the same manner as in Example 1 except that the polyurethane water-based resin paint was not applied.
The results of performing a performance test on the resulting decorative paper were as follows.
[0035]
Abrasion resistance: The end point (until the disappearance of the pattern 1/2) was 40 times.
Weather resistance: In an irradiation test using Wether-O-Meter, the end point (until fading, whitening, etc.) was 500 hours.
Water resistance: No abnormality after 1 week of immersion in room temperature water Solvent resistance: Passed JAS thinner test Flexibility: Cracks occurred in a 180-degree bending test.
Elongation: 6%
[0036]
Comparative Example 2
A decorative paper was produced in the same manner as in Example 1 except that a commercially available impregnated paper in which the impregnating resin was only a thermoplastic resin was used.
The results of performing a performance test on the resulting decorative paper were as follows.
[0037]
Abrasion resistance: The end point (until the disappearance of the pattern 1/2) was 100 times.
Weather resistance: The end point (until discoloration, whitening, etc.) was 1000 hours in the irradiation test with Wether-O-Meter.
Water resistance: No abnormality after 1 week of immersion in room temperature water Solvent resistance: Passed JAS thinner test Flexibility: Cracks occurred in a 180-degree bending test.
Elongation: 7%
[0038]
Comparative Example 3
A decorative paper was produced in the same manner as in Example 1 except that an oil-based urethane resin paint (viscosity 550 cp) was applied instead of the polyurethane-based water-based resin paint, but the high-viscosity oil-based urethane resin paint was difficult to apply uniformly. In addition to causing unevenness of gloss, unevenness of stripes and the like, and foaming in the drying process, the product was judged to be defective in appearance inspection.
[0039]
When the above-mentioned oil-based urethane resin paint was used with a gravure ink having a viscosity of about 100 cp, slight gloss unevenness and stripe unevenness were observed. The results of the performance test were as follows, and were easily cracked and insufficient in elongation.
[0040]
Abrasion resistance: The end point (until the disappearance of the pattern 1/2) was 80 times.
Weather resistance: The end point (until discoloration, whitening, etc.) was 600 hours in the irradiation test with Wether-O-Meter.
Water resistance: No abnormality after 1 week of immersion in room temperature water Solvent resistance: Passed JAS thinner test Flexibility: Cracks occurred in a 180-degree bending test.
Elongation: 5%
[0041]
Comparative Example 4
A decorative paper was produced in the same manner as in Example 1 except that a styrene acrylic emulsion (viscosity 550 cp) was used instead of the urethane-based water-based resin paint. The performance of the decorative paper obtained was as follows, and the water resistance and solvent resistance were inferior.
[0042]
Abrasion resistance: The end point (until the disappearance of the pattern 1/2) was 100 times.
Weather resistance: The end point (until discoloration, whitening, etc.) was 1000 hours in the irradiation test with Wether-O-Meter.
Water resistance: 1 week immersion in room temperature water Whitening solvent resistance: JAS thinner test rejected Flexibility: 180 degree bending test showed no cracks.
Elongation: 10%
[0043]
Example 2
The following (1) to (3) are mixed to prepare an impregnating resin solution having a resin solid content of 35% by weight.
(1) Polyacrylate copolymer emulsion 45 parts Particle size 0.1 mμ, TG-20 ° C
(2) Vinyl acetate / acrylic ester emulsion 45 parts Particle size 0.1mμ, TG18 ° C
(3) Isocyanate (water dispersion type) 10 parts
A decorative paper was produced in the same manner as in Example 1 except that the impregnating resin solution was changed to the above. The quality of the decorative paper obtained was equivalent to that of Example 1.
[0045]
Example 3
The following (1) to (3) are mixed to prepare an impregnating resin solution having a resin solid content of 35% by weight.
(1) Styrene butadiene copolymer latex 90 parts Particle size 0.1 mμ, TG-20 ° C
(2) Isocyanate (water dispersion type) 10 parts
A decorative paper was produced in the same manner as in Example 1 except that the impregnating resin solution was changed to the above. The quality of the decorative paper obtained was equivalent to that of Example 1.
[0047]
Example 4
In addition to using a urethane resin colloidal dispersion with an epoxy crosslinking agent and adjusting the viscosity to 550 cp (urethane resin solid / epoxy crosslinking agent solid = 100/5) as a urethane water-based resin coating Made a decorative paper in the same manner as in Example 1. The quality of the decorative paper obtained was equivalent to that of Example 1.
[0048]
Example 5
Besides adding a melamine cross-linking agent to a urethane resin colloidal dispersion and adjusting the viscosity to 550 cp (urethane resin solid / melamine cross-linker solid = 100/5) as a urethane water-based resin coating Made a decorative paper in the same manner as in Example 1. The quality of the decorative paper obtained was equivalent to that of Example 1.
[0049]
Example 6
The same as in Example 1 except that a water-dispersed isocyanate was mixed with a colloidal dispersion of polyol and the viscosity was adjusted to 550 cp (polyol solid / isocyanate solid = 100/40) was used as the urethane-based aqueous resin coating. Thus, a decorative paper was produced. The quality of the decorative paper obtained was equivalent to that of Example 1.
[0050]
Example 7
After the 25% by weight fine powdered aluminum oxide (average particle size 9 μm) of the resin solid was mixed as a wear resistance improver in the same polyurethane-based water-based resin paint used in Example 1, well dispersed, The viscosity was adjusted to 550 cp using a diluent.
[0051]
A decorative paper was produced in the same manner as in Example 1 except that the polyurethane-based aqueous resin coating containing aluminum oxide was used instead of the polyurethane-based aqueous resin coating applied on the printed layer. Although the high specific gravity aluminum oxide easily settles in the paint, in this example dispersed in the high-viscosity polyurethane-based aqueous resin paint, the aluminum oxide did not settle and could be uniformly distributed on the decorative paper.
[0052]
The finish of the obtained decorative paper was good, and the end point in the abrasion resistance test was 150 times, and the abrasion resistance was remarkably improved as compared with that of Example 1. The other performance was equivalent to that of Example 1.
[0053]
Example 8
A decorative paper was produced in the same manner as in Example 7 except that a polyurethane-based water-based resin coating material in which 1% by weight of powdered polyurethane (average particle size 25 μm) of resin solids was mixed with finely powdered aluminum oxide was used.
[0054]
The finish of the resulting decorative paper was good, and the surface having fine irregularities due to the mixed powdery polyurethane had a touch close to that of natural wood. The result of the performance test was equivalent to that in Example 7.
[0055]
When a resin paint mixed with aluminum oxide is applied, wear of the gravure plate is accelerated, but in this case where powdered polyurethane having a particle size larger than that of aluminum oxide is mixed, this is the case of Example 2 in which only aluminum oxide is mixed. In comparison, the wear rate of the gravure plate was about ½.
[0056]
【The invention's effect】
The impregnated paper impregnated with the thermoplastic resin and the thermosetting resin is slightly contracted in the width direction in the process of being subjected to resin impregnation and drying while being pulled in the length direction. The impregnated thermoplastic resin enables the elongation due to the restoration of the shrinkage in the width direction. Moreover, the surface protective layer by the urethane type water-based resin coating applied on a printing layer also has a big elongation. Therefore, the decorative board manufactured using the decorative paper according to the manufacturing method of the present invention has a larger elongation and higher strength of the decorative paper layer than the decorative board manufactured using the conventional paper-based decorative paper. Therefore, it is excellent in bending workability and sufficiently withstands V-cut processing.
[0057]
Urethane-based water-based resin paints not only give decorative paper with a high degree of elongation, but also high-viscosity coatings with high solids concentration can be applied at high speed by gravure printing to form uniform and thick coatings with high efficiency. There are advantages that can be made. Also, even if aluminum oxide is added to improve wear resistance, sedimentation separation due to difference in specific gravity is unlikely to occur, so a large amount of aluminum oxide can be contained to form a coating film containing aluminum uniformly at a high rate. it can.
[0058]
Therefore, according to the present invention, it is possible to produce a paper-based decorative paper excellent in bending workability, surface characteristics, water resistance, solvent resistance, abrasion resistance, and the like with high productivity.

Claims (6)

For the surface protective layer formation, printing is performed on a base paper impregnated with a mixture of a thermoplastic resin and a thermosetting resin, and a coating for forming a transparent surface protective layer is applied to the printed surface to produce a decorative paper. A method for producing decorative paper, characterized in that the coating is performed first using a polyurethane-based water-based resin paint and then using an oil-based polyurethane-based resin paint. Acrylic resin emulsions, synthetic rubber latex, a water-soluble acrylic resin solution and a thermoplastic resin aqueous dispersion selected from the group consisting of an aqueous polyurethane dispersion, thermal selected from aqueous epoxy resin and the water-dispersible isocyanate or Ranaru group, The method for producing decorative paper according to claim 1, wherein a base paper reinforced by impregnating a mixture with a curable resin prepolymer is used.   The method for producing decorative paper according to claim 1 or 2, wherein a base paper impregnated with a thermoplastic resin and a thermosetting resin in a ratio of 50:50 to 95: 5 is used.   The method for producing a decorative paper according to any one of claims 1 to 3, wherein a polyurethane-based aqueous resin paint having a viscosity adjusted to 300 to 1000 cp is coated by a gravure printing method.   The method for producing decorative paper according to any one of claims 1 to 4, wherein an abrasion resistance improving material made of finely powdered aluminum oxide is mixed in the polyurethane-based aqueous resin paint.   6. The decorative paper according to claim 5, wherein a thermosetting resin powder having a particle diameter larger than that of the aluminum oxide is mixed together with a wear resistance improving material made of finely powdered aluminum oxide into the polyurethane-based water-based resin paint. Law.