JP2001323637A - Formaldehyde trapping plaster building material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plaster building material having one or two or all of excellent formaldehyde trapping property, moisture absorbing/releasing property, water repellency, and size stability while maintaining excellent performance, expediency, and excellent economical efficiency. SOLUTION: A formaldehyde trapping material is mixed in plaster serving as main material to form this plaster building material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum-based building material containing a formaldehyde-scavenging substance (herein, "formaldehyde-scavenging" means that formaldehyde is absorbed, adsorbed, reacted, converted, decomposed, altered, denatured, denatured, modified, etc.). , From formaldehyde to free form).
More specifically, the present invention relates to a gypsum-based building material such as a gypsum board or a gypsum plaster suitable for interior construction of walls and ceilings of houses having excellent formaldehyde trapping properties, moisture absorption / release properties, water repellency and dimensional stability.

[0002]

2. Description of the Related Art In the recent housing industry, while cost reduction is being promoted by rationalizing and improving efficiency of construction methods, building materials are being improved in performance and quality is being stabilized.
From the viewpoint of energy saving, designs and constructions for increasing the airtightness and the heat insulation of the indoor space are increasing in many cases. Along with this, indoor air pollution by VOCs (volatile organic compounds) generated from adhesives of building materials, furniture, and the like, especially formaldehyde, which is a representative substance thereof, has become a problem. In order to prevent indoor air pollution due to this formaldehyde, a method using an adhesive or the like that does not contain formaldehyde, a method of reducing the concentration of formaldehyde in a room by ventilation, and the like have been conventionally proposed.

[0003]

However, the above-described method has the following problems. That is,
The adhesives and the like which do not contain formaldehyde have inferior performance and are very expensive as compared with the adhesives and the like which contain formaldehyde, and thus cannot be said to be a preferable solution. Although the method using ventilation is simple, there is a problem that a large energy loss for cooling and heating is caused. Under such circumstances, there has been a keen need for the development of interior building materials that have excellent formaldehyde trapping performance and are easy to apply to construction and finishing.

[0004] In view of such circumstances, the present inventors have conducted intensive studies on formaldehyde trapping properties. As a result, the present inventors have found that a formaldehyde trapping substance is blended into a gypsum-based building material that is frequently used as an interior base material. By
The excellent formaldehyde trapping performance of this substance can be maintained even in gypsum-based building materials.If the substance is used in combination with an inorganic moisture-absorbing / desorbing substance, the performance of both substances is not offset, and the excellent formaldehyde trapping performance is obtained. It was found that formaldehyde was not released again upon reheating.

[0005] The present invention has been made based on these findings, and its object is to provide excellent performance and convenience,
To provide a gypsum-based building material having one or more performances among excellent formaldehyde scavenging properties, moisture absorption / desorption properties, water repellency and dimensional stability while maintaining excellent economy, and furthermore all the performances. is there.

[0006]

The above object is achieved by the present invention described below. That is, the present invention provides a gypsum-based building material, characterized in that a gypsum as a main material is mixed with a formaldehyde-trapping substance. In the present invention, the gypsum-based building material refers to a gypsum board, a fiber gypsum board, a gypsum plaster, a gypsum-based putty or a gypsum-based joint treatment material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments of the present invention. The present inventors have conducted intensive studies in order to solve the above-mentioned problems of the prior art,
(A) As described above, by mixing a formaldehyde-trapping substance into gypsum as a main material, it is possible to impart formaldehyde-trapping properties to a gypsum-based building material while maintaining the formaldehyde-trapping properties of the substance. ,
(B) In addition, by using the gypsum as a main material together with the formaldehyde-trapping substance and the inorganic moisture-absorbing / desorbing substance, excellent formaldehyde-trapping performance is obtained, and excellent moisture-absorbing and releasing property is obtained. Moreover, it is possible to prevent formaldehyde from being re-released at the time of reheating. (C) Further, by using a water repellency-imparting agent in combination, it is excellent in water repellency and dimensional stability, and the material is "rough" when absorbing water. Gypsum-based building materials in which various problems such as warpage and cracks caused by the above can be effectively prevented, and (d) even if blended as in (b) or (c) above, the performance of each component is The present invention has been found that it is possible to synergistically add the performance of each component to a gypsum-based building material without being offset or causing any adverse effect.

Next, each material used in the present invention will be described. First, gypsum used as a main material of the gypsum-based building material of the present invention is a natural gypsum, phosphate gypsum, a known β-type hemihydrate gypsum which has been calcined by using chemical gypsum represented by gypsum alone or in combination. , Α-type hemihydrate gypsum or a mixture thereof.

The formaldehyde-trapping substance to be added to the gypsum-based building material of the present invention will be described. Examples of the formaldehyde-capturing substance that can be used in the present invention include all known types, for example, oxides or hydroxides of alkaline earth metals such as magnesium, calcium, barium, and strontium, and water of polyvalent metals. Oxides, carbonates of alkali metals, acetates, known weak alkaline substances such as ammonium carbonate can be used.
Ammonium salts or derivatives thereof as described in JP-A-11-128329, specifically, ammonium amidosulfate and the like are desirable.

The amount of the formaldehyde scavenger is 0.01 to 3 parts by weight per 100 parts by weight of gypsum.
Preferably it is 0.1 to 1 part by weight. The formaldehyde-trapping substance can increase the formaldehyde-trapping performance as the amount thereof is increased, but is not preferable because the formaldehyde-trapping substance is very expensive and is inferior in economy. On the other hand, if the amount is less than 0.01 part by weight, the amount is too small, so that no apparent formaldehyde trapping performance is exhibited.

Further, the inorganic moisture-absorbing and desorbing substance to be added to the gypsum-based building material of the present invention will be described. The inorganic hygroscopic substance that can be used in the present invention is not particularly limited, and any substance that exhibits hygroscopicity depending on the surrounding humidity where the gypsum-based building material is placed can be used. For example, clay minerals such as zeolite group, diatomaceous earth (for example, diatom shale of Wakkanai layer), apatargite, and montmorillonite (acid clay) are generally known, and any of these can be used in the present invention. In particular, those obtained by calcining or acid-treating these are known to exhibit better moisture absorption / release performance than untreated products, and are particularly suitable. For example, activated clay obtained by treating acid clay with acid can be suitably used. Of course, one or more of the above-mentioned inorganic hygroscopic substances may be used in combination.

The amount of the inorganic hygroscopic substance to be incorporated is 3 to 30 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of gypsum.
To 20 parts by weight. These inorganic hygroscopic substances
The moisture absorption / desorption performance can be increased by increasing the blending amount, but on the other hand, blending beyond the above range is not preferred because the strength of the gypsum-based building material is reduced. On the other hand, if the compounding amount is less than 3 parts by weight, the gypsum-based building material will not exhibit a clear improvement in moisture absorption / desorption performance.

The water repellency imparting agent to be added to the gypsum building material of the present invention will be described. As the water repellency-imparting agent that can be used in the present invention, any known types can be used.However, the present inventors have studied in consideration of performance, price, curing time, and the like. It has been found that the following silicone water repellents and / or paraffin water repellants are suitable.

[0014] Preferable examples of the silicone-based water repellency-imparting agent include, for example, organosiloxanes described in Japanese Patent No. 2739872 and those described in Japanese Patent No. 2686792. An organopolysiloxane can be mentioned. Preferred examples of the paraffin-based water repellency-imparting agent include JP-B-7-6.
No. 1889, waxes having a melting point of 40 to 90 ° C. and olefin-maleic anhydride derivatives,
An emulsion obtained by adding polyvinyl alcohol to an emulsion emulsified in water under alkalinity can be exemplified.

The blending amount of the water repellency-imparting agent is not particularly limited, as long as the elongation of the material at the time of water absorption can be suppressed.
(Based on SA6901) as long as the total water absorption is 10% or less, and the elongation at the time of total water absorption for 2 hours can be suppressed to 0.1% or less. If it is a silicone-based water repellency imparting agent, plaster 100
0.05 to 1 part by weight, preferably 0.3 part by weight
To 0.7 parts by weight, and 0.5 to 5 parts by weight, preferably 2 to 4 parts by weight based on 100 parts by weight of gypsum in the case of a paraffin-based water repellent. When the amount of these water repellency-imparting agents is increased within the above range, the above-mentioned 2
The total water absorption for 2 hours and the elongation at 2 hours of total water absorption can be reduced, resulting in good water repellency and dimensional stability. Such a cost becomes expensive, resulting in poor economic efficiency. On the other hand, in any of the water repellency-imparting agents, if the amount is less than the above range, the amount is too small and desired water repellency and dimensional stability cannot be obtained.

In the gypsum-based building material of the present invention, as described above, a formaldehyde-trapping substance is blended into the main gypsum, or a formaldehyde-trapping substance and an inorganic moisture-absorbing / desorbing substance are used in combination. By blending the two components together with a water repellency-imparting agent, their respective performances are simultaneously effective in a gypsum-based building material without offsetting the performance of each or causing the harmful effects of blending each. Can be added synergistically in an appropriate state. As a result, it is possible to obtain a gypsum-based building material having both excellent moisture absorption / desorption properties, water repellency, and dimensional stability, as well as excellent formaldehyde scavenging properties, and all the properties.

The gypsum board, which is a typical example of the gypsum-based building material of the present invention, can be manufactured in a usual gypsum board production line. As other compounding materials, for example, pulp fiber and / or glass fiber It goes without saying that a known admixture, a known foaming agent, a setting regulator and the like can be used.
Similarly, gypsum plaster, gypsum-based putty or gypsum-based joint treatment material of the gypsum-based building material of the present invention can be similarly produced by a usual production apparatus, and other compounding materials include perlite and / or vermiculite. It is needless to say that known lightweight aggregates such as mica and fillers such as mica, known viscosity regulators and setting regulators can be used.

[0018]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The gypsum-based building material of the present invention is mainly composed of gypsum, and exhibits similar performance as a building material. Therefore, a gypsum board will be described here as an example. In carrying out the tests of Examples and Comparative Examples, ammonium amidosulfate was used as the formaldehyde-trapping substance. Specifically, it is "ammonium amidosulfate" (first-class reagent) manufactured by Kanto Chemical Co., Ltd. Activated clay was used as an inorganic moisture absorbing / releasing substance. Specifically, "Nikkalite G-36" (trade name) manufactured by Nippon Activated Shirato Co., Ltd. was used. Further, a silicone-based water repellent was used as the water repellent. Specifically, “K” manufactured by Shin-Etsu Chemical Co., Ltd.
F-99 "(trade name).

[Pretreatment of Gypsum Board Sample] From the obtained gypsum board sample, six test pieces each of 30 cm square were collected and dried at a constant temperature of 40 ° C. to obtain test pieces for measurement. Then, two sheets each were used for measuring the moisture absorption / release properties, for measuring the formaldehyde scavenging property, for measuring the total water absorption for 2 hours, and for measuring the elongation rate at the time of total water absorption for 2 hours.

[Measurement of Moisture Absorption and Desorption] The amount of moisture absorption and desorption was determined by first sealing all the surfaces except for the surface of the test piece with an aluminum tape so that moisture was absorbed and released only from the surface of the test piece. The test piece was allowed to stand in a thermo-hygrostat at room temperature 25 ° C. and 50% relative humidity for 24 hours, and then at room temperature 25 ° C. and relative humidity 90%.
The sample was allowed to stand in a thermo-hygrostat for 24 hours to measure the moisture absorption of each test piece. Next, the test piece was further allowed to stand in a thermo-hygrostat at room temperature 25 ° C. and relative humidity 50% for 24 hours to measure the amount of moisture release. Then, the average value of the measured values of the two obtained test pieces was used as the measurement result, and Table 1 was used.
3 to 3.

[Measurement of formaldehyde scavenging performance] Formaldehyde scavenging performance was measured by first sealing all the surfaces except for the surface of the test piece with aluminum tape so that moisture was absorbed and released only from the surface of the test piece. At room temperature 2
After standing for 24 hours in a thermo-hygrostat at 5 ° C. and 70% RH, 0.35 weight of formaldehyde was placed in a 5-liter closed container in a thermo-hygrostat at room temperature 25 ° C. and 70% RH. % Diluent and 2 ml of the test piece were placed side by side, and the air concentration of formaldehyde in the sealed container was measured with a GV-100S gas detector tube manufactured by Gastech Co., Ltd. at each elapsed time. (Air concentration after 3 hours) to compare formaldehyde scavenging properties. The average value of the measured values of the two obtained test pieces was defined as the measurement result (equilibrium air concentration), and is shown in Tables 1 to 3.

Further, the test piece capturing the above-mentioned formaldehyde is taken out, immediately put in a new 5 liter closed container in a thermo-hygrostat at room temperature 25 ° C. and relative humidity 70%, and left to stand. , The temperature in the thermo-hygrostat to 4
Raise the temperature to 0 ° C, measure the air concentration of formaldehyde in the sealed container at each elapsed time with a gas detector tube, and compare the re-release properties of formaldehyde based on the equilibrium air concentration (air concentration after 3 hours). did. Table 1 shows the average value of the measured values of the two obtained test pieces as the measurement result (re-emission air concentration).
3 to 3.

[Measurement of Total Water Absorption and Elongation] The total water absorption for 2 hours was measured by immersing a test piece in water at 20 ± 3 ° C. for 2 hours according to the method specified in JISA6901.
Also, at this time, the dial gauge was fixed by a piece support in the longitudinal direction and the width direction of the test piece, and the elongation ratio at the time of total water absorption for 2 hours was measured.

Examples 1 to 3 and Comparative Example 1 In a normal gypsum board production line, "ammonium amidosulfate" to be mixed with the gypsum core was changed in the range of 0.1 to 1 part by weight per 100 parts by weight of gypsum. Example 1
3 gypsum board was obtained. Further, a gypsum board in which “ammonium amidosulfate” was not blended was also manufactured under ordinary manufacturing conditions, and a gypsum board of Comparative Example 1 was obtained. Each of these gypsum boards was a gypsum board having a thickness of 12.5 mm and a specific gravity of 0.70. The above-mentioned pretreatment was performed on the above four types of gypsum boards, and the formaldehyde scavenging property was measured. Table 1 shows the results.

Examples 4 to 12 The amounts of "ammonium amidosulfate" to be blended into the gypsum core in the usual gypsum board production line using the blending materials shown in Table 2-1 were 0.1 parts per 100 parts by weight of gypsum. The amount of "Nikkalite G-36" was changed in the range of 5 to 20 parts by weight with respect to 100 parts by weight of gypsum. 4 to 12 of 9
Different types of gypsum board were obtained. Each of these gypsum boards was a gypsum board having a thickness of 12.5 mm and a specific gravity of 0.70. Each gypsum board was subjected to the same pretreatment as described above, and the formaldehyde trapping performance, the moisture absorption / desorption property, and the total water absorption were measured in accordance with the above measurement methods. The results are shown in Table 2-1.

Examples 13 to 39 In addition to the above combinations of Examples 4 to 12,
The amount of “KF-99” to be blended into the gypsum core
By changing the range of 0.3 to 0.7 parts by weight with respect to parts by weight, 27 types of gypsum boards of Examples 13 to 39 were obtained.
Each of these gypsum boards was a gypsum board having a thickness of 12.5 mm and a specific gravity of 0.70. Each gypsum board was similarly subjected to the same pretreatment as described above, and the formaldehyde trapping performance, the moisture absorption / release properties, and the total water absorption were measured in accordance with the above-described measurement methods. The results are shown in Tables 2-2 to 4-2.

Comparative Examples 1 to 7 In a normal gypsum board production line, gypsum 1
No Nicarite G-36, Ammonium Amidosulfate, and KF-99 were added, and Nikkalite G-36 was added in an amount of 5 to 2 parts by weight.
0 parts by weight, "KF-99" is 0.3 to 0.1%.
About 7 parts by weight, seven types of gypsum boards of Comparative Examples 1 to 7 having the composition shown in Table 3 were obtained. Each of these gypsum boards was a gypsum board having a thickness of 12.5 mm and a specific gravity of 0.70, similarly to the gypsum boards obtained in the examples. These gypsum boards were similarly subjected to the same pretreatment as described above, and the formaldehyde trapping performance, the moisture absorption / release properties, and the total water absorption were measured in accordance with the above-described measurement methods. Table 3 shows the results. In Table 3, Comparative Example 1 is for the same sample as that of Table 1.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

[0033]

[Table 6]

As shown in Table 1, by adding a formaldehyde-trapping substance to a gypsum board, Comparative Example 1 was used.
It is clear that the average air concentration of formaldehyde and the re-emission air concentration at reheating can be greatly reduced as compared to

Further, as is apparent from Table 2-1, Examples 4 to 12 in which both the inorganic moisture-absorbing and desorbing substance and the formaldehyde-trapping substance were combined, the inorganic moisture-absorbing and desorbing substance and the formaldehyde-trapping substance were mixed. Than in Comparative Examples 2 to 7 in which only one of the active substances was blended (Table 3), the equilibrium air concentration and the re-emission concentration of formaldehyde were significantly reduced while maintaining the same moisture absorption and desorption performance. It was confirmed that the formaldehyde trapping performance was particularly improved.

Further, in Examples 13 to 39 in which all of the inorganic moisture-absorbing and desorbing substance, the formaldehyde scavenging substance and the water repellency-imparting agent were blended, the results were higher than those in Examples 1 to 12.
It has been confirmed that the total water absorption can be significantly reduced and the elongation can be reduced while maintaining the moisture absorption / desorption performance and the formaldehyde trapping performance at the same level.

From the above, (1) By blending a formaldehyde-trapping substance with gypsum as a main material, it is possible to impart the excellent formaldehyde-trapping property of the substance to a gypsum-based building material; By blending both the system moisture-absorbing / desorbing substance and the formaldehyde-trapping substance into the main gypsum, excellent formaldehyde-trapping properties and hygroscopic properties can be effectively imparted to the gypsum-based building material. (3) By adding a water repellency-imparting agent to gypsum as a main material, it is clear that excellent formaldehyde trapping properties, moisture absorption / release properties, water repellency and dimensional stability can be effectively imparted to gypsum-based building materials. .

[0038]

As described above, according to the present invention,
A gypsum that combines all of the properties of excellent formaldehyde scavenging, moisture absorption / desorption, water repellency, and dimensional stability, while maintaining excellent performance, convenience, and economy Based building materials are obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C04B 22:14 C04B 22:14 Z 14:10 14:10 Z A 24:24 24:24 B 24:42 24:42 24:00) 24:00) (72) Inventor Takeshi Goto 2-1-1, Eboku, Adachi-ku, Tokyo Yoshino Gypsum Co., Ltd. F-term (Reference) 2E001 DB03 DH00 DH23 FA06 FA14 GA11 GA51 HA03 HA21 HA22 HA23 HB01 2E110 AA14 AA27 AA64 AB03 AB04 AB23 GA33W GB11W GB16W GB18W 4G012 MB04 PA06 PB26 PB41 PC01 PC11 PC13

Claims (8)

[Claims] 1. A gypsum-based building material characterized in that a gypsum as a main material is mixed with a formaldehyde-scavenging substance. 2. The gypsum-based building material according to claim 1, further comprising an inorganic hygroscopic substance. 3. A gypsum-based building material according to claim 1, further comprising a water repellency-imparting agent. 4. The gypsum building material according to claim 1, wherein the formaldehyde-trapping substance is an ammonium salt or a derivative thereof. 5. The gypsum-based building material according to claim 4, wherein the formaldehyde-trapping substance is ammonium amidosulfate. 6. The gypsum-based building material according to claim 2, wherein the inorganic hygroscopic substance is at least one selected from a clay mineral, a calcined product thereof, and an acid-treated product. 7. The gypsum-based building material according to claim 6, wherein the inorganic hygroscopic substance is activated clay. 8. The gypsum-based building material according to claim 3, wherein the water repellency imparting agent is a silicone water repellency imparting agent and / or a paraffin water repellency imparting agent.