JPH10296918A - Decorative sheet and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To capture effectively formaldehyde brought about from plywood or the like by a method wherein a formaldehyde capturing layer containing a formaldehyde capturing material is formed on one surface of a paper base, and a decorative layer and a protective layer are formed sequentially on the other surface of the paper base. SOLUTION: A formaldehyde capturing layer is formed by coating or impregnating one surface of a paper base of wood free paper, thin leaf paper, Japan art paper or kraft paper with a coating solution prepared by adding a material having a function of capturing formaldehyde, an additive and others arbitrarily to a solvent type or emulsion type vehicle of nitrocellulose/alkyd, cellulose, vinyl chloride or the like and by kneading them. Moreover, a layer of decoration of a pattern such as an ink pattern layer or a metallic layer and a protective layer constituted of transparent resin are formed sequentially on the other surface of the paper base. According to this constitution, the formaldehyde brought about from plywood or the like can be captured effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative sheet used for interior decoration of buildings, surface decoration of fittings, furniture such as cupboards and chests, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, this type of decorative sheet generally uses a paper substrate as a substrate, and a printed sheet obtained by printing on the substrate is used as it is, and the decorative sheet is attached to the surface of an adherend. Has been used as However, many adherends to which a decorative sheet is attached are formed using a material that generates formaldehyde.
For example, a formaldehyde-generating substance such as a urea resin is used for an adhesive for forming a wood plywood, a particle board, a wood fiber board, or the like, a resin constituting the FRP, or a resin constituting the resin base itself. Therefore, if a printing sheet is directly stuck to such an adherend, formaldehyde is released into a room or the like, which impairs the indoor sanitary environment.

[0003]

Therefore, many proposals have been made as a method for preventing the release of formaldehyde from these adherends. For example, measures have been taken to use a formaldehyde-free resin such as a vinyl acetate resin, or to add a formaldehyde-trapping substance composed of an organic amino compound to a formaldehyde-generating resin such as a urea resin. However, since the resin containing no formaldehyde has a low adhesive strength, in the case of plywood, there is a problem that the interlayer adhesive strength becomes insufficient (particularly, the initial adhesive strength is weak). In such a case, there is a problem that physical properties such as strength are changed. In addition, when a formaldehyde scavenger is used by adding it to the adherend itself, the price increases and
There is also the problem that the physical properties of the finished product may change.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a decorative sheet having a harmful formaldehyde trapping function and a method for producing the same. As a substance having a formaldehyde trapping action, an organic amino compound is a typical one, and a decorative sheet having a formaldehyde trapping function is usually provided with a formaldehyde trapping layer containing an organic amino compound. The formaldehyde trapping layer is designed to trap formaldehyde released from an adherend or the like.

[0005] In addition, the decorative sheet has a wood grain pattern, a solid pattern,
A decorative layer such as an abstract pattern is usually provided, and a protective layer is further provided to protect the decorative layer and improve the friction and chemical properties of the decorative sheet surface, but the protective layer is suitable for processing, cost and performance. In view of the above, a two-component curable polyurethane resin in which a main agent having a polyol group is reacted with a curing agent having an isocyanate group has been widely used. In addition, a two-component curable polyurethane resin may be used for the decorative layer in order to improve the adhesiveness to the paper substrate.

However, a decorative sheet having a protective layer formed of the two-component curable polyurethane resin and a formaldehyde trapping layer formed of an organic amino compound is difficult to obtain at the time of production. The isocyanate, which is an agent, and the amine of an organic amino compound react to form a urethane monomolecule, thereby eliminating the function of trapping formaldehyde and preventing the two-component curable polyurethane resin, which is the protective layer, from being completely cured. A problem arises in that the friction and chemical properties of the surface do not reach the desired resistance.

Accordingly, the present invention has been made in view of the above-mentioned problems, and has as its object the following:
Provided is a decorative sheet having a formaldehyde trapping function, comprising a two-component curable polyurethane-based resin for at least one of a protective layer and a decorative layer, and using an organic amino compound for a formaldehyde trapping layer, and a method for producing the same. Is to do.

[0008]

According to a first aspect of the present invention, there is provided a decorative sheet according to the present invention, wherein a formaldehyde-trapping layer containing a formaldehyde-trapping substance is formed on one surface of a paper substrate. A decorative layer and a protective layer are sequentially formed on the other surface of the base.

According to a second aspect of the present invention, in the decorative sheet according to the first aspect, at least one of the decorative layer and the protective layer is made of a resin that is urethane-bonded by an isocyanate group. is there.

According to a third aspect of the present invention, at least one of the decorative layer and the protective layer is made of a resin that is urethane-bonded by an isocyanate group. Forming the protective layer on the entire layer surface, the decorative layer, after curing the protective layer,
A method for producing a decorative sheet, comprising forming a formaldehyde trapping layer on the other surface of the paper substrate. By producing in this manner, the amount of the isocyanate remaining as an unreacted substance in the decorative layer or the protective layer of the two-component curable polyurethane resin formed on one surface of the paper substrate can be minimized. As a result, the reaction with the amine of the formaldehyde trapping layer which permeates the paper substrate and is provided on the other surface can be minimized. Further, since the decorative sheet is usually in the form of a roll at the time of production, the protective layer provided on one side of the paper substrate comes into contact with the formaldehyde capturing layer provided on the other side. Also, the unreacted isocyanate in the protective layer is minimal,
The reaction of the formaldehyde trapping layer with the amine can be minimized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Paper substrates include high quality paper, thin paper, Japanese paper, kraft paper, titanium paper, linter paper, paperboard,
Gypsum board paper is used. These paper substrates may be either a single body or a laminate of two or more layers.

The decorative layer provided on the surface of the paper substrate includes formation of a decorative layer composed of a pattern of an ink picture layer and a metal layer, formation of an uneven pattern, and the like.

When a pattern is formed by the ink picture layer, a known printing method such as gravure printing, offset printing, letterpress printing, silk screen printing or the like can be used, but drawing may be used. The picture layer is nitrified cotton / alkyd, cellulose, vinyl chloride, vinyl chloride-vinyl acetate, acrylic, acrylic polyol,
An ink composed of an ester-based or urethane-based vehicle and a pigment or dye is formed in an arbitrary pattern. Examples of the pattern include a wood grain pattern, a stone grain, a cloth grain, a leather crest, characters, figures, and other wood grain patterns, an abstract pattern, and a solid surface.

The pattern formed by the metal layer is formed by vacuum-depositing a metal such as aluminum, chromium, gold, silver, or copper. The metal layer may be formed on the entire surface, or may be formed partially in a pattern such as a pattern.

As a method of forming the concavo-convex pattern, a concavo-convex pattern having a concavo-convex shape is formed on the substrate by hairline processing, sand plasting, embossing, or the like.

The embossing is performed by using a hot press type sheet-fed or rotary embossing machine, pressing an embossing plate on the surface of a heated and softened paper substrate, and shaping the unevenness on the surface of the embossing plate. This is a method of forming a pattern.
Examples of the concavo-convex pattern formed by the embossing include a pattern expressing a wood grain conduit groove, a wood grain, a stone surface unevenness, a surface texture of a cloth, a satin finish, a grain, a hairline, or a combination thereof. Also,
The concave portions of the concavo-convex pattern are filled with coloring ink by a known wiping method as necessary. As the coloring ink, those obtained by adding a pigment or a dye to a urethane resin, an acrylic resin, a polyester resin, or other common vehicles are selectively used, and a two-liquid curing type having good adhesion and solvent resistance is preferable. Wiping may be performed by any of conventionally used wiping methods such as a doctor blade method and a roll coating method. By these methods,
The coloring ink is applied to the entire surface of the uneven pattern, and then the ink on the convex portion is scraped off, and the coloring ink is left on the concave portion. Further, an easy-adhesion primer layer for improving the adhesive strength between the paper substrate and the decoration layer may be provided between the paper substrate and the decoration layer, if necessary.

Next, a protective layer made of a transparent resin is formed on the decorative layer, that is, on the outermost surface of the decorative sheet, for the purpose of protecting the decorative sheet from the effects of abrasion, water, chemicals and the like. ing. As a resin for forming the protective layer, a cellulose resin, an acrylic resin, a two-component curable polyurethane resin, a fluororesin, or the like is used. From the viewpoint of workability, cost, performance, etc., a two-component curable polyurethane resin is used. Usually used frequently. As a method of forming the protective layer, a coating liquid obtained by adding and kneading an additive or the like to the vehicle of the resin is coated by a known coating method such as gravure printing, roll coating, and knife coating. It can be formed, and the coating amount is 1 to 5 g / m2 when dry.
² is appropriate. In addition, coloring may be performed by adding a pigment, a dye, or the like, if necessary.

Next, the formaldehyde trapping layer is formed of a solvent type such as a nitrified cotton / alkyd type, a cellulose type, a vinyl chloride type, a vinyl chloride-vinyl acetate type, an acrylic type, an acrylic polyol type, an ester type, or an emulsion type vehicle. It can be formed by coating or impregnating a paper substrate with a coating liquid kneaded by arbitrarily adding a substance having a capturing effect and an additive. Representative substances having a formaldehyde scavenging action are organic amino compounds, for example, urea, ethylene urea, propylene urea, 5-hydroxypropylene urea, 5-methoxy propylene urea, 5-methyl propylene urea, parabanic acid (glyoxal monourea). Rain), 4,5-dimethoxyethylene urea, pyrrolidine, piperidine, morpholine, 2-hydrazobenzothiazole or derivatives thereof, amines such as dicyandiamide, amides, and imides. Further, ammonium hydroxide may be added as needed. Further, the formaldehyde-trapping substance may be supported on an inorganic powder such as silica, talc, clay, activated carbon, zeolite, and sepiolite.

However, when the decorative layer and the protective layer are formed on the paper substrate, when at least one of the decorative layer and the protective layer is formed of a resin that is urethane-bonded by an isocyanate group, the above-mentioned isocyanate group is used. Before the urethane-bonded resin is cured, that is,
When a formaldehyde trapping layer made of an organic amino compound is formed on a paper substrate during the course of curing, the isocyanate (unreacted isocyanate) before urethane bonding reacts with the amine of the organic amino compound to convert urethane monomolecules. It forms and reduces the function of capturing formaldehyde, and the polyurethane resin, which is the protective layer, is not completely cured, so that the frictional and chemical properties of the decorative sheet surface or the adhesive strength between the paper substrate and the decorative layer can reach the expected resistance. The result is not reached.

Further, even when a paper substrate on which a formaldehyde-trapping layer comprising an organic amino compound is formed in advance is used, at least one of the decorative layer and the protective layer is formed of a resin which is urethane-bonded to the paper substrate by an isocyanate group. In the formed decorative sheet, the same result as in the preceding paragraph is obtained.

Accordingly, the present invention relates to a resin having a formaldehyde trapping layer formed of an organic amino compound formed on a paper substrate and having at least one layer of a decorative layer or a protective layer bonded to the surface of the paper substrate by urethane bonding with an isocyanate group. In the case of manufacturing the formed decorative sheet, a decorative layer is provided on one surface of the paper substrate, the protective layer is formed on the entire surface of the decorative layer, and then provided on at least one of the decorative layer or the protective layer. By subjecting the resin to be urethane-bonded by an isocyanate group to a treatment such as thermal aging and curing, the unreacted isocyanate is almost completely eliminated, and then a formaldehyde capturing layer comprising an organic amino compound is formed on the other surface of the paper substrate. Forming has the function of trapping formaldehyde and completely cures polyurethane resin It is possible to obtain a decorative sheet having a strongly adherent decorative layers on friction and chemical resistance excellent protective layer or paper substrate surface.

[0022]

The present invention will be described in more detail with reference to the following examples. Example 1 A woodgrain pattern layer was formed on one surface of a thin paper having a basis weight of 30 g / m ² by gravure printing using a nitrocellulose ink, and a two-component curable polyurethane resin was applied over the entire surface of the woodgrain pattern pattern layer. A surface protective layer is formed by a gravure printing method using the liquid, and after being heat-dried at 40 ° C. for 48 hours,
A nitrocellulose-based coating liquid containing 10% of a clay supporting piperidine of a 6-membered saturated cyclic secondary amine as a formaldehyde-trapping substance was printed on the other surface of the tissue paper by a gravure printing method. A decorative sheet A formed with was prepared. Comparative Example 1 A woodgrain pattern layer was formed on one surface of a thin paper having a basis weight of 30 g / m ^{2 with} a nitrocellulose ink by a gravure printing method, and a two-component curable polyurethane resin was coated on the entire surface of the woodgrain pattern pattern layer. After forming a surface protective layer by a gravure printing method using a liquid, 10% of a clay carrying piperidine of a 6-membered saturated cyclic secondary amine which is a formaldehyde trapping substance is continuously formed on the other surface of the tissue paper. The added nitrocellulose-based coating liquid was printed by a gravure printing method to prepare a decorative sheet B on which a formaldehyde capturing layer was formed.

Comparative Example 2 A wood pattern pattern layer was formed on one surface of a thin paper having a basis weight of 30 g / m ² by gravure printing using a nitrocellulose-based ink, and a two-component curable polyurethane resin was applied to the entire surface of the wood pattern pattern layer. A decorative sheet C was prepared by forming a surface protective layer by a gravure printing method using the coating liquid of Example 1.

Formaldehyde trapping layers of the decorative sheets A, B, and C are formed on both sides of a 2.5 mm wood plywood in which the decorative sheets A, B, and C are laminated together with a lauan veneer with an urea resin adhesive. The decorative plate was prepared by bonding the thus-formed surface or the paper substrate surface to the wood plywood side using an ethylene-vinyl acetate adhesive.

The decorative boards using the decorative sheets A, B and C prepared in Example 1 and Comparative Examples 1 and 2 were subjected to a formaldehyde quantitative test specified in Japanese Agricultural Standards, and the results are shown in Table 1. It is shown together.

[0026]

[Table 1] As is clear from Table 1, the decorative board using the decorative sheet A having the formaldehyde capturing layer produced by the production method of the present invention was effective in capturing formaldehyde generated from wood plywood. The decorative board using the decorative sheet B having the formaldehyde capturing layer has the effect of capturing the formaldehyde generated from the wood plywood as compared with the decorative board using the decorative sheet C having no formaldehyde capturing layer. The result was inferior to the effect of sheet A. Therefore, the superiority of the decorative sheet A produced by the production method of the present invention was confirmed.

[0027]

As described above, the decorative sheet of the present invention can effectively capture formaldehyde generated from wood plywood and the like, and the decorative sheet of the present invention is manufactured by the manufacturing method of the present invention. Thereby, it has a performance of effectively capturing formaldehyde.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B32B 33/00 B32B 33/00

Claims (3)

[Claims] 1. A formaldehyde trapping layer containing a formaldehyde trapping substance is formed on one surface of a paper substrate,
A decorative sheet, wherein a decorative layer and a protective layer are sequentially formed on the other surface of the paper substrate. 2. The decorative sheet according to claim 1, wherein at least one of the decorative layer and the protective layer is made of a resin that is urethane-bonded by an isocyanate group. 3. At least one of the decorative layer and the protective layer is made of a resin that is urethane-bonded by an isocyanate group. The decorative layer is provided on one surface of a paper substrate, and the protective layer is formed on the entire surface of the decorative layer. And forming a formaldehyde trapping layer on the other surface of the paper substrate after curing the decorative layer and the protective layer.