JPH10337803A - Gypsum board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent bad health or discomfort feeling of a resident suffering from a gypsum board, by giving formaldehyde capturing and removing functions to the gypsum board to be used for an inner wall face or ceiling face of a building. SOLUTION: The gypsum board comprises a formaldehyde capturing layer 3 on a surface of a gypsum layer 2. The layer 3 has a resin layer obtained by coating or immersing a gypsum board base sheet 1 with formaldehyde scavenger or incorporating the scavenger in the sheet 1. Or, a decorative sheet 7 having a resin layer 5 containing formaldehyde scavenger may be pasted on a surface of a base material sheet 6. The resin layer containing the scavenger is preferably an aqueous resin layer containing hydrazine derivative.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum board for use as a wall material or a ceiling material of buildings such as houses and office buildings. For more information,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum board having a function of trapping and removing formaldehyde that is diffused by building materials such as wood materials and adhesives to prevent health damage and discomfort.

[0002]

2. Description of the Related Art In recent years, it has been used as an adhesive for wood materials such as plywood, laminated wood, MDF, and particle board, which are used as building materials for houses, office buildings, and the like, and for attaching wallpaper for decoration to walls and the like. Formaldehyde is released from the adhesive and contaminates the indoor air, depending on the constitution of the resident and the user, may cause health damage such as allergic symptoms, or may cause discomfort due to its unique odor. It has been pointed out that there are cases in which there are cases in which there is a problem.

[0003] As a countermeasure, various measures have been studied, such as changing the adhesive used for processing wood materials or attaching wallpaper or the like to an adhesive containing no formaldehyde, or adding a formaldehyde scavenger. . However, all of these measures have problems in terms of cost and physical properties, and have not been widely spread.

[0004] That is, a urea resin-based adhesive, which is a typical wood adhesive, contains a relatively large amount of formaldehyde, but is inexpensive as compared with other adhesives. At present, it is used much more than other adhesives (phenolic resin, aminoacetal resin, etc.) because of its superiority in terms of initial adhesiveness.

[0005] In addition, most of the adhesives used for affixing wallpaper and the like to wall surfaces and the like are starch glue which is most excellent in all aspects such as cost, workability and adhesiveness. It is necessary to add a preservative in order to prevent mold and the like, and most of them contain formaldehyde which is inexpensive, has excellent preservative effect, and does not affect workability and adhesiveness.

[0006] Adhesives used for any of the above purposes, while exhibiting the same price and performance as conventional adhesives but containing no formaldehyde, are still seen despite the efforts of many manufacturers and the like. At present, there is no prospect of realizing complete non-formation of houses, etc. at present.

Of course, if the material such as plywood containing a large amount of formaldehyde is replaced by a wood material that does not substantially contain formaldehyde, such as gypsum board, the inner walls and ceilings of the building are constructed, It would be possible to reduce the contamination of room air with formaldehyde without significantly increasing building costs.

However, since wood materials and gypsum boards are materials having different basic performances in terms of workability, strength, weight, etc., it is not possible to substitute all the internal constituent materials of a building. It is impossible, and in practice wood materials must be used together. In addition, it is necessary to decorate the inner wall surface, the ceiling surface and the like, but the problem of the adhesive used for attaching the decorative material such as the wallpaper cannot be solved by this method.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in a conventional building, and has been developed in consideration of a gypsum board for use as a wall material or a ceiling material of a building. The purpose of the present invention is to provide a function of trapping and removing formaldehyde emitted from building materials such as wood materials and adhesives, thereby reducing the concentration of formaldehyde in the room and contributing to prevention of health damage and discomfort.

[0010]

The gypsum board of the present invention comprises:
The present invention is characterized in that a formaldehyde trapping layer is provided on the surface of the gypsum layer.

[0011] In particular, the formaldehyde-trapping layer is a gypsum board base paper containing a formaldehyde-trapping agent.

[0012] In particular, the formaldehyde-trapping layer is a resin layer containing a formaldehyde-trapping agent provided on the surface of the gypsum board base paper.

[0013] Further, the present invention is characterized in that the formaldehyde-trapping layer is a decorative sheet containing a formaldehyde-trapping agent attached to the surface of a gypsum board base paper.

[0014] In particular, the decorative sheet containing the formaldehyde scavenger has a resin layer containing a formaldehyde scavenger on the surface of the base sheet.

[0015] In particular, the resin layer containing the formaldehyde scavenger is an aqueous resin layer containing a hydrazine derivative.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in FIG. 1 is an embodiment of the simplest construction of the gypsum board of the present invention, in which a gypsum layer 2 is used.
The gypsum board base papers 1 and 3 are provided on both the front and back surfaces of the gypsum board, and the gypsum board base paper 3 on the front side contains a formaldehyde scavenger. In addition, the gypsum board base paper 1 on the back side may or may not contain a formaldehyde scavenger.

The same material as the conventional gypsum board can be used as the material for the gypsum board base papers 1, 3 and the gypsum layer 2.
There is no particular limitation. That is, the gypsum board base papers 1 and 3
Generally, the grammage is 100 g / m ² or more, and usually, the grammage is 270 to 3
A paperboard of about 60 g / m ² , with the front side having strength, smoothness, and water resistance, while the back side is porous paper that is rich in water absorption so as to be in close contact with the cast gypsum layer. In addition, a certain degree of air permeability is required so that excess moisture is released when the gypsum layer is cured.

The material of the gypsum layer 2 is a gypsum slurry obtained by kneading gypsum powder with water together with a reinforcing agent such as pulp and various additives. After being molded to a predetermined thickness, it is hydrated, cured and dried.
The thickness of the gypsum board varies depending on the application, but generally has a thickness of 7 to 15 mm.

As the formaldehyde scavenger contained in the gypsum board base paper 3, any substance having a function of reacting physically or chemically with formaldehyde to change it into a harmless and odorless state can be used. In particular, dicyandiamide is used. It is preferable to use nitrogen-containing compounds such as amino compounds such as melamine, amides such as urea and barbituric acid, amino acids such as glutamate, glycine and alanine, and hydrazine derivatives such as carbohydrazide and adipic dihydrazide.

As a method of including a formaldehyde scavenger in the gypsum board base paper 3, for example,
A method of adding a formaldehyde scavenger to a pulp slurry during papermaking, a method of applying or impregnating a gypsum board base paper 3 with a solution containing a formaldehyde scavenger, a solution containing a formaldehyde scavenger after casting and hardening the gypsum slurry An arbitrary method such as a method of applying a liquid is applicable.

However, since the method of adding at the time of paper making is difficult to cope with a small lot, and the method of applying after molding and curing is inferior in production efficiency, a chemical containing a formaldehyde scavenger is applied to or impregnated on the paper-made gypsum board base paper 3. After that, it is most preferable to adopt a method of molding and curing the gypsum layer 2.

Further, as shown in FIG.
If necessary, a pattern layer 4 in which an arbitrary pattern such as a wood pattern, a stone pattern, an abstract pattern, or the like is formed by a printing method or the like may be provided as necessary. In addition, although not shown, an uneven pattern may be formed on the surface of the gypsum board base paper 3 by an embossing method or the like. In particular, when an uneven pattern synchronized with the pattern of the pattern layer 4 is formed, a design suitable for interior decoration is obtained. Excellent things can be made.

The above printing and embossing can be performed after the molding and curing of the gypsum layer 2, but the method of molding and curing the gypsum layer 2 using the gypsum board base paper 3 which has been preliminarily printed and embossed is more preferable. This is common because of its excellent production efficiency.
As a printing method, any conventionally known method such as a gravure printing method, an offset printing method, and a screen printing method can be applied.

The embossing method is generally a roll embossing method in which a base paper is pressed between a cylindrical male mold and a female mold.
According to a valet printing method in which a colorant is attached to a convex portion of an embossing roll to perform embossing, a method in which a pattern layer 4 made of a liquid-repellent ink is provided, and a resin layer 5 described later is coated, etc. It is possible to easily form an uneven pattern synchronized with the above.

In this way, if a design such as a picture or an emboss is applied to the surface of the gypsum board in advance, an interior decoration effect can be obtained only by applying the design as a wall surface or a ceiling surface, and the wallpaper and the like can be applied. In addition to omitting the process, it can also contribute to the prevention of indoor air contamination due to the adhesive used when attaching wallpaper or the like.

Further, in order to impart surface properties such as water resistance and abrasion resistance to the surface of the gypsum board, as shown in FIG.
The resin layer 5 can be provided on the surface of the gypsum board base paper 3. As the resin layer 5, a resin having excellent air permeability and moisture permeability, such as a urethane resin, an acrylic resin, an aminoalkyd resin, a nitrified cotton resin, etc., in order to release surplus moisture when the gypsum layer 2 is cured, is required. Is selected, and the coating amount is about 10
It is usually suppressed to g / m ² or less.

However, if the resin layer 5 is provided on the surface of the gypsum board base paper 3 as described above, the formaldehyde scavenger contained in the gypsum board base paper 3 cannot directly contact the indoor air. Significantly reduces the formaldehyde scavenging efficiency. Therefore, when the resin layer 5 is provided on the surface of the gypsum board base paper 3, it is preferable that the resin layer 5 contains a formaldehyde scavenger instead of the gypsum board base paper 3.

As described above, when the resin layer 5 containing the formaldehyde scavenger is provided on the surface, the indoor air is in direct contact with the resin layer 5 containing the formaldehyde scavenger. Formaldehyde contained can be efficiently captured and removed by the formaldehyde capturing agent contained in the resin layer 5.

The resin layer 5 may be provided, if necessary, with, for example, a coloring agent, a filler, an extender, a lubricant, a gloss adjusting agent, a lubricant, an antistatic agent, a stabilizer, a plasticizer, a surfactant, Desired physical properties can be imparted by appropriately adding an additive such as an adhesion aid.

As a method for forming the resin layer 5, a coating solution dissolved or dispersed in an appropriate solvent is applied, for example, by a gravure coating method, a die coating method, a lip coating method, or the like.
Coating by various coating methods such as knife coating method, air knife coating method, spray coating method, flow coating method, roll coating method, etc., and heat and pressure etc. with or without an adhesive formed into a film shape A conventionally known arbitrary method such as a method of sticking by a method, a method of extrusion-coating a resin melted by heating and the like can be appropriately applied.

The resin layer 5 can be a plurality of layers made of the same or different resins as required. At this time, not all the resin layers 5 need to contain a formaldehyde scavenger, and if at least one of them contains a formaldehyde scavenger, a formaldehyde scavenging function can be imparted.

However, if the resin layer 5 containing no other formaldehyde scavenger is provided on the surface of the resin layer 5 containing the formaldehyde scavenger, the resin layer 5 containing the formaldehyde scavenger of formaldehyde in the air may be used.
There is a risk that the arrival at the surface will be impeded and a sufficient formaldehyde trapping effect will not be achieved. Therefore, of the plurality of resin layers 5, the uppermost resin layer 5 contains a formaldehyde scavenger or the resin layer 5 provided on the formaldehyde scavenger-containing resin layer 5.
Is preferably a thin layer made of a material rich in formaldehyde permeability.

If necessary, a surface pattern layer made of a colored resin or a resin having a gloss different from that of the resin layer 5 may be provided on the surface of the resin layer 5. However, when the area ratio of the surface pattern layer is high and the film thickness is large, the arrival of formaldehyde in the air to the resin layer 5 is prevented, and as a result, the formaldehyde trapping ability may be reduced. Therefore, when a surface pattern layer is provided, it is preferable to use a pattern with many omissions or a thin layer that does not hinder the transmission of formaldehyde.

As described above, when a formaldehyde scavenger is contained in the resin layer 5, the surface properties such as abrasion resistance and water resistance are reduced, and the design of the underlying picture layer 4 is deteriorated. It is necessary to pay attention so that no
That is, examples of inexpensive and easy-to-handle substances having a formaldehyde trapping effect include amino compounds and amino acids, which are generally low molecular weight hydrophilic compounds.

Therefore, if a large amount is added to the resin in an attempt to improve the formaldehyde trapping ability, the mechanical strength and water resistance of the resin layer decrease, the coating suitability of the coating liquid and the drying property deteriorate, There is a case where problems such as whitening and deterioration of the design property occur due to poor compatibility with the above, and when these problems are avoided, the obtained formaldehyde trapping ability is naturally limited.

From this viewpoint, it is preferable that the formaldehyde scavenger contained in the resin layer 5 should be capable of binding to a resin molecule at its terminal group. One of the specific examples is a hydrazine derivative. The hydrazine derivative can react with a functional group such as a carboxyl group or a carbonyl group in the molecule of the resin and chemically bond with the functional group.
When a resin containing a functional group such as a carboxyl group or a carbonyl group in the molecule is used, the hydrazine derivative is chemically stabilized in the resin by the above-mentioned bond, and the surface strength and the water resistance are not reduced. Bleeding and whitening due to separation can also be suppressed.

As the hydrazine derivative, specifically,
For example, organic hydrazines such as isopropylhydrazine, butylhydrazine, benzylhydrazine, phenylhydrazine, hydrazobenzene, and the like, methylcarbazate, propionic hydrazide, carbohydrazide, adipic hydrazide, dodecandiohydrazide, thiocarbohydrazide, isophthalic dihydrazide And hydrazides such as 4,4'-oxybisbenzenesulfonyl hydrazide.

Particularly, as the hydrazine derivative,
For example, when using a compound containing a plurality of hydrazino groups, such as carbohydrazide or adipic dihydrazide,
This acts as a crosslinking agent between the molecular chains of the resin,
This is the most preferable since a resin layer 5 which is more excellent chemically can be obtained.

Even if the hydrazino group reacts with and binds to a functional group in the resin molecule, since the NH bond still remains in the molecule, the ability to capture formaldehyde is not lost. However, if the NH bond is reduced by such a reaction, the ability to capture formaldehyde is inevitably reduced, and it is undeniable that the molecular movement is hindered and the reaction activity is reduced, so that the unreacted hydrazino group is reduced as much as possible. It is preferable to make the hydrazine derivative excessively contained so as to remain in the resin.

As described above, the resin used for the resin layer 5 containing the hydrazine derivative is preferably a resin containing a functional group such as a carboxyl group or a carbonyl group.
Ketone or ester solvents having high solubility in such resins cannot be used because they themselves react with the hydrazine derivative. Therefore, it is preferable to use an aqueous resin as the resin, taking advantage of the fact that hydrazine derivatives are generally rich in water solubility.

Specifically, for example, acrylic resin, acrylic-vinyl acetate resin, acrylic-styrene resin,
An aqueous emulsion resin composed of a polyester-based resin, an alkyd-based resin, a urethane-based resin, a modified polyolefin resin, or the like can be suitably used.

As described above, when an aqueous resin is used as the resin constituting the resin layer 5, problems such as volatilization of the organic solvent during production and odor due to the residual solvent can be solved at the same time. Is excellent in air permeability and moisture permeability, so that excess moisture can be quickly discharged at the time of molding and curing of the gypsum layer, which is effective in preventing blister defects.

When a hydrazine derivative having a plurality of hydrazino groups is used also as a cross-linking agent, it is not necessary to use a harmful cross-linking agent such as isocyanate, which is conventionally used, which is easy to volatilize. There is also an advantage that a product having excellent physical properties can be obtained in a simple working environment.

By the way, as described above, the gypsum board base paper 3
Is generally quite thick paperboard, the process of directly printing or coating the pattern layer 4 or the resin layer 5 on it has some problems in terms of printing / coating suitability and workability, as well as gypsum slurry. Is performed in a continuous manner, it is also difficult to cope with multi-product small-lot production corresponding to various desired patterns.

Therefore, as shown in FIG. 4, it is an object of the present invention to provide a configuration in which a decorative sheet 7 containing a formaldehyde scavenger is adhered to the surface of a normal gypsum board not containing a formaldehyde scavenger. This is very suitable because not only the formaldehyde trapping function is sufficiently realized, but also the suitability for printing and coating and workability are improved, and it is easy to cope with high-mix low-volume production.

The decorative sheet 7 is, as is conventionally known,
The pattern layer 4 having a desired pattern is provided on a suitable base sheet 6 such as paper or a resin film, and the formaldehyde scavenger may be contained in the base sheet 6. However, in order to improve the durability by imparting surface properties such as abrasion resistance and water resistance, it is preferable to have a resin layer 5 on the surface.
It is preferable that the formaldehyde scavenger be contained in the resin layer 5 for the same reason as when the resin layer 5 is provided thereon.

The plaster board base paper 3 also described above
For the same reason as when the resin layer 5 is provided thereon, the resin layer 5 is preferably an aqueous resin layer having a hydrazine derivative, and among these, a compound containing a plurality of hydrazino groups may be used as the hydrazine derivative. Most preferred.

[0048]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to several specific examples and comparative examples of the present invention.

Example 1 A formaldehyde scavenger aqueous solution containing melamine as a main component was dried on a gypsum board base paper surface of a commercially available gypsum board having a thickness of 9 mm (trade name: Tiger board, manufactured by Yoshino Gypsum Co., Ltd.). Later application amount 6g / m
² was impregnated with a roll to prepare a gypsum board of the present invention.

The gypsum board is coated with a coating amount of 100 g / m ^2.
(Wet), a vinyl cloth as a decorative material was adhered via an adhesive containing formaldehyde (Aminol (trade name, manufactured by Yayoi Chemical Co., Ltd.)).
Using 10 pieces cut to the size of
After placing in a desiccator together with a crystal dish containing 00 ml and sealing, leaving it at 20 ° C. for 24 hours, formaldehyde in distilled water was quantified by the acetylacetone method, and the amount of formaldehyde emission was 0.5 mg / l.

<Comparative Example 1> In Example 1, the amount of formaldehyde emission was measured under the same conditions as in Example 1 except that the coating impregnation with the formaldehyde scavenger was omitted.
0.9 mg / l.

<Example 2> An acrylic aqueous ink was used on the surface of a gypsum board base paper having a basis weight of 300 g / m ^2.
An acrylic-based water-based topcoat agent with a 10% solids ratio of adipic acid dihydrazide as a formaldehyde scavenger is applied on top of a picture layer of an abstract pattern by color gravure printing to a coating amount of 10 g / m ² after drying. Then, a gypsum board base paper was prepared.

Using the above-mentioned decorative gypsum board base paper as a cover and the same untreated gypsum board base paper as a backing paper, a gypsum slurry was poured in between, and molded to a thickness of 9 mm, cured and dried to obtain the present invention. A gypsum board was made.

The same procedure as in Example 1 was performed by using five pieces of the gypsum board cut to 50 mm × 150 mm and five pieces of a commercially available medium-density fiberboard having a thickness of 3 mm cut to 50 mm × 150 mm. It was 1.2 mg / l when the formaldehyde emission amount was measured in the same manner.

<Comparative Example 2> In Example 2, a gypsum board was prepared under the same conditions as above except that adipic dihydrazide was not added to the aqueous acrylic topcoat agent, and the amount of formaldehyde emission was measured. 4.5
mg / l.

Example 3 An abstract pattern layer was provided on thin paper having a basis weight of 30 g / m ² by three-color gravure printing using an aqueous acrylic ink, and adipic dihydrazide was solidified thereon as a formaldehyde scavenger. Division ratio 10
% Of the acrylic aqueous topcoat agent was applied to a coating amount of 10 g / m ² after drying to prepare a decorative sheet containing a formaldehyde scavenger.

The thin paper of the above decorative sheet is applied to the surface of a gypsum board base paper on the surface of a commercially available gypsum board having a thickness of 9 mm (trade name: Tiger board manufactured by Yoshino Gypsum Co., Ltd.) via a vinyl acetate resin-based aqueous emulsion adhesive. The gypsum board of the present invention was prepared by sticking the surface to the gypsum board base paper surface.

The same procedure as in Example 1 was carried out by using five pieces of the gypsum board cut to 50 mm × 150 mm and five pieces of a commercially available medium-density fiberboard having a thickness of 3 mm cut to 50 mm × 150 mm. It was 1.3 mg / l when the formaldehyde emission amount was measured in the same manner.

<Comparative Example 3> In Example 2, a gypsum board was prepared under the same conditions as above except that adipic dihydrazide was not added to the aqueous acrylic topcoat agent, and the amount of formaldehyde emission was measured. 5.3
mg / l.

[0060]

The gypsum board of the present invention is provided with a formaldehyde trapping layer on the surface of the gypsum layer, so that it can be used as a wall material or a ceiling material in buildings such as houses and office buildings. Captures and removes formaldehyde emitted from wood materials and adhesives used as building materials to reduce formaldehyde concentration in indoor air, resulting in health hazards and discomfort to residents and users. Etc. can be prevented.

That is, when used as a base material for wall coverings such as vinyl cloth, paper wallpaper, textile wallpaper, etc., those containing formaldehyde may be used as such wall coverings, Even if an adhesive containing is used, the formaldehyde trapping layer of the gypsum board of the present invention traps and removes the above-mentioned formaldehyde, so that the indoor air can be prevented from being contaminated by formaldehyde.

Further, if the gypsum board of the present invention is used as a wall material or a ceiling material, even if wood materials, adhesives, and the like used in other parts diffuse formaldehyde into the indoor air, the gypsum board can be used as a gypsum board. Since the formaldehyde of the gypsum board of the invention captures and removes it, the concentration of formaldehyde in the indoor air can be reduced. In a room, the sum of the wall surface and the ceiling surface occupies more than half of the total contact area of the room air, so that the effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a gypsum board of the present invention.

FIG. 2 is a side sectional view showing an embodiment of the gypsum board of the present invention.

FIG. 3 is a side sectional view showing an embodiment of the gypsum board of the present invention.

FIG. 4 is a side sectional view showing an embodiment of the gypsum board of the present invention.

[Explanation of symbols]

 1 gypsum board base paper 2 gypsum layer 3 gypsum board base paper 4 pattern layer 5 resin layer 6 base material sheet 7 decorative sheet 8 adhesive layer

Claims (6)

[Claims] 1. A gypsum board comprising a formaldehyde trapping layer on the surface of a gypsum layer. 2. The gypsum board according to claim 1, wherein the formaldehyde scavenging layer is a gypsum board base paper containing a formaldehyde scavenger. 3. The gypsum board according to claim 1, wherein the formaldehyde-trapping layer is a resin layer containing a formaldehyde-trapping agent provided on the surface of the gypsum board base paper. 4. The gypsum board according to claim 1, wherein the formaldehyde-trapping layer is a decorative sheet containing a formaldehyde-trapping agent attached to a surface of a gypsum board base paper. 5. The gypsum board according to claim 4, wherein the decorative sheet containing the formaldehyde scavenger has a resin layer containing the formaldehyde scavenger on the surface of the base sheet. 6. The gypsum board according to claim 3, wherein the resin layer containing the formaldehyde scavenger is an aqueous resin layer containing a hydrazine derivative.