JP2884228B2 - Aldehyde emission control method for wood-based materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood-based material which suppresses emission of aldehydes such as formaldehyde from wood-based materials such as plywood manufactured using an adhesive containing aldehydes. The present invention relates to a method for suppressing aldehyde emission.

[0002]

2. Description of the Related Art As is well known, in the fields of building materials and furniture, wood-based materials such as plywood and particleboard are often used because of their low cost. These wood-based materials are manufactured using an adhesive for laminating a plurality of veneers or hot-pressing wood fragments, and the adhesive includes, for example, a urea resin-based material. An adhesive or the like is used.

[0003] Since the urea resin-based adhesive uses formaldehyde as a raw material, the product adhesive contains unreacted formaldehyde which is easily volatilized. Therefore, it is known that formaldehyde is emitted from wood-based materials manufactured using this urea resin-based adhesive over a long period of time. In addition, even when a wood-based material is manufactured using other adhesives such as a phenolic resin-based, melamine resin-based, resorcinol resin-based, and butyral resin-based adhesive, aldehydes such as formaldehyde are used as raw materials. It is known that, as described above, aldehydes which are easily volatilized contained in the adhesive are diffused from the wood-based material.

[0004] Conventionally, as a generally used harmful substance adsorbing material, for example, activated carbon and zeolite are known.

[0005]

However, aldehydes such as formaldehyde are harmful to the human body. Therefore, wood-based materials manufactured using adhesives containing these aldehydes, even if they are equivalent to the highest rank of JAS (Japanese Agricultural Standards), are used as materials for buildings and furniture. There is a problem that aldehydes are emitted into a building or a room for a long period of time, and the living environment is continuously polluted.

[0006] For this reason, the number of people who complain of abnormalities in the body due to the aldehydes is increasing. As a means for dealing with this, effective means other than frequent ventilation in a building or a room are used. It has not been proposed yet.

Further, in the above-mentioned activated carbon, zeolite and the like, since harmful substances are adsorbed by physical action, adsorbed substances are easily released by stimulation such as application of heat, and therefore, the reliability of the adsorbent material is lacking. There is.

The present invention has been made in view of the above circumstances and problems, and can suppress the emission of aldehydes to improve the cleanliness and comfort of a living environment.
It is an object of the present invention to provide a method for suppressing the emission of aldehydes from wood-based materials with high reliability.

[0009]

Means for achieving the above object are as follows. First, the surface of a wood-based material manufactured using an adhesive containing aldehydes is melted.
Chitosan which is liquid and has a deacetylation degree of 30% or more
The amino group content is based on the aldehyde group content of the aldehydes.
After spraying or spraying to make it 2 to 20 times
This chitosan is dried by drying
It is to adhere or carry the material so as to cover the surface of the material . Second , using an adhesive containing aldehydes
On the surface of the wood-based material manufactured by
0 μm or less in powder form having a deacetylation degree of 30% or more
Chitosan is converted to an aldehyde having an amino group content of
Rub it in 2 to 20 times the amount of aldehyde group
Or adhered or carried by spraying
It is to be.

[0010]

Embodiments of the present invention will be described below. The method for suppressing the emission of aldehydes from a wood-based material according to the embodiment includes a method of removing a solution in the form of a solution on the surface of a wood-based material manufactured using an adhesive containing aldehydes.
Chitosan with an acetylation degree of 30% or more has an amino group content of
2 to 20 with respect to the aldehyde group content of the aldehydes
Dry after applying or spraying to double
By doing so, this chitosan can
Attached or carried to cover , or itself
Is in the form of a powder having a particle size of 200 μm or less,
Rub or spray to the above ratio
And is caused to adhere or be carried .

Examples of the adhesive containing aldehydes include adhesives containing aldehydes such as urea resin-based, phenolic resin-based, melamine resin-based, resorcinol resin-based, and butyral resin-based adhesives. Further, as a wood-based material manufactured using this adhesive, for example, for bonding of a plurality of veneers, such as plywood or particle board, or for hot-pressing wood fragments, etc. One using such an adhesive is exemplified.

The chitosan has a degree of deacetylation.
30% or more can be used, and when processing in powder form
In this case, a particle having a particle size of 200 μm or less can be used .

[0013] In order to adhere or carry the chitosan having a degree of deacetylation of 30% or more on the surface of the wood-based material ,
When the chitosan is in the form of a solution dissolved in a suitable solvent,
Viscosity due to dissolution of chitosan, a molecular compound
Apply or spray this solution with film forming properties
This chitosan is dried by drying after drying.
What is necessary is just to adhere | attach so that the surface of a wooden material may be covered. Ma
In addition, when the chitosan is in the form of powder,
Rubbing or spraying into the micropores on the surface of the
do it.

[0014] The amount of adhering or carrying the chitosan to the surface of the wood-based material, an amino group of the chitosan, 2 to 20 times the aldehyde group amount of aldehydes contained in the adhesive and if so that <br/> rather good, the processing cost if treated with the amount is not high
There are advantages.

[0015] According to the method for suppressing aldehydes emission from wood-based materials constituted as described above, the aldehyde groups of the aldehydes to be emitted from the adhesive are replaced with the chitosa.
Because it is attracted by the fact that reacts with amino groups of the emissions,
The emission of aldehydes from the wood-based material can be suppressed.

Further, aldehyde groups to form Schiff bases linked to amino groups chemically, does not easily decomposed if not acidic conditions, after the chitosan is adsorbed aldehydes may facilitate this aldehydes Will not be released. Therefore, there is an advantage that the reliability is high, unlike the conventional method in which adsorption and desorption of activated carbon, zeolite and the like are repeated.

Here, when the chitosan is in the form of a solution,
Is attached or carried to cover the surface of the wooden material.
And if it is in powder form, a table of wood-based materials
This chitosa only attaches to the micropores on the surface.
Are trying to radiate from the surface of wood-based materials.
Reacts only with wood and aldehydes contained in wood-based materials.
Does not react with hides. Therefore, chitosan is more than necessary
Reacts with other aldehydes and reduces the adhesive strength of the adhesive
There is an advantage that there is no. Also, chitosan in solution
When using a solution of chitosan, which is a polymer compound,
Since the liquid is viscous and has film-forming properties, this chitosan
It is coated over the entire surface of the wood-based material. for that reason,
Aldehydes to be released can be adsorbed more efficiently
The advantage is that On the other hand, the chitosan itself has a particle size of 2
If 00μm or less in powder form, the table of woody material
It is possible to easily attach or supported by operating the rub or sprayed on the surface, by Ino easily filled in the micropores of the surface of the wood-based materials, that can be increased and the deposition amount
There are advantages.

In addition, the degree of deacetylation is 30% or more.
Since chitosan is derived from a natural product produced by deacetylation of chitin obtained from crustaceans, insects, microorganisms, etc., this chitosan is coated so as to cover its surface or
There is an advantage that the safety of the wood-based material adhered or carried on the surface by rubbing or the like is high.

[0019]

EXAMPLES Hereinafter, the method for suppressing the emission of aldehydes from the woody material of the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A plywood for furniture having a thickness of 3 mm was prepared by laminating a wood material and a lauan material one by one with a urea resin adhesive, and cut into a size of 5 cm in width and 15 cm in length. And A large number of these test pieces were prepared. Cellulose powder (Avicel, for chromatography, average particle size 11 μm) and chitosan powder (Kyoyo Chemical Co., Ltd., SK400) were used as formaldehyde adsorbents for every ten test pieces. Diameter 3μ
m, deacetylation degree 80%), chitosan powder (SK400, manufactured by Koyo Chemical Co., Ltd.)
m, deacetylation degree 80%), chitosan powder (manufactured by Koyo Chemical Co., Ltd., SK400F, average particle size 10)
(0 μm or more, degree of deacetylation: 80%). In addition, SK laser 7000S manufactured by Seishin Enterprise was used for particle size measurement.

Next, ten test pieces each rubbed with the above-mentioned formaldehyde adsorbent were put in a desiccator together with a crystal dish containing 300 ml of distilled water, and allowed to stand in a thermostat at a temperature of 30 ° C. for 24 hours. For comparison, an untreated test piece 1 not treated with the formaldehyde adsorbent was used.
The same operation was performed for 0 sheets.

After 24 hours, distilled water in the crystallizing dish was taken out, and the concentration of formaldehyde absorbed in the distilled water was measured by the acetylacetone method. This measuring method is based on J
According to AS (Japanese Agricultural Standards, formaldehyde emission test), only the temperature condition was changed to 30 ° C. The results of the measurement are shown in the following Table 1 and FIG.

[0023]

[Table 1]

[0024] As is clear from Table 1 and Figure 1, cellulose
Treatment reduces the amount of formaldehyde emission
In contrast to chitosan, the emission was greatly suppressed.

Example 2 After a plywood for furniture was prepared in the same manner as in Example 1, the amount of formaldehyde contained in the plywood for furniture was measured first.

That is, the furniture plywood was crushed, and 10 g of the plywood was immersed in 200 ml of distilled water and left at room temperature for 30 minutes. Next, the filtrate from which the wood was removed by suction filtration was made up to 500 ml in a volumetric flask, and formaldehyde was quantified by the acetylacetone method.
Was obtained. That is, this furniture plywood contains 2 mg formaldehyde per 10 g. Therefore, the test piece 10 made in the same manner as in Example 1 from the plywood for furniture
Per sheet (about 113 g), formaldehyde
2.6 mg (about 0.8 mM).

Next, a large number of these test pieces were prepared in the same manner as in Example 1, and 10 test pieces were used as a formaldehyde adsorbent as an aqueous solution of chitosan acetate (available from Koyo Chemical Co., SK
10 was dissolved in a 4% acetic acid aqueous solution at a concentration of 10%, and the degree of deacetylation was 80%. Separately, for every 10 test pieces,
Chitosan powder (manufactured by Koyo Chemical Co., Ltd., SK400 pulverized to an average particle size of 3 μm, deacetylation degree 80%), chitosan powder (manufactured by Koyo Chemical Co., DAC100 pulverized to an average particle size of 3 μm, deacetylation degree) (100%). Next, the same operation as in Example 1 was performed to measure the formaldehyde concentration.
The results of the measurement are shown in Table 2 below.

[0028]

[Table 2]

Here, the amount of amino groups of the formaldehyde adsorbent is determined, for example, by the chitosan powder (DAC10
0, average particle size of 3 μm), the degree of deacetylation is 1
Since 10% of the test pieces have a glucosamine residue of about 4 mM at 00%, it is about 5 times the aldehyde group amount (about 0.8 mM) of formaldehyde obtained by the above measurement.

As is apparent from Table 2 , chitosan acetate
It was found that the treatment with the aqueous solution or the chitosan powder significantly suppressed the emission of formaldehyde.

[0031]

As described above, according to the first and second aspects of the present invention, a degree of deacetylation of 30% is applied to the surface of a wood-based material produced using an adhesive containing aldehydes.
Since depositing or carrying or chitosan, since the aldehyde group of aldehyde to be dissipated from the adhesive is sucked <br/> wear by that react with amino groups of the chitosan, woody materials Aldehydes can be suppressed from being released from the air.

Further, since the aldehyde group is chemically bonded to the amino group to form a Schiff base and is not easily decomposed, the chitosan is not easily released after the aldehyde is adsorbed, and the chitosan is not easily released. There is an advantage that the property is high.

Here, when the chitosan is in a solution state
Is attached or carried to cover the surface of the wooden material.
And if it is in powder form, a table of wood-based materials
This chitosa only attaches to the micropores on the surface.
Are trying to radiate from the surface of wood-based materials.
Reacts only with wood and aldehydes contained in wood-based materials.
Does not react with hides. Therefore, chitosan is more than necessary
Reacts with other aldehydes and reduces the adhesive strength of the adhesive
There is an advantage that there is no. Also, chitosan in solution
When using a solution of chitosan, which is a polymer compound,
Since the liquid is viscous and has film-forming properties, this chitosan
It is coated over the entire surface of the wood-based material. for that reason,
Aldehydes to be released can be adsorbed more efficiently
The advantage is that On the other hand, the chitosan itself has a particle size of 2
If 00μm or less in powder form, the table of woody material
It is possible to easily attach or supported by operating the rub or sprayed on the surface, that since easily filled in the micropores of the surface of the wood-based materials, can be increased and the deposition amount
There are advantages.

In addition, the degree of deacetylation is 30% or more.
Chitosan is a kiti obtained from crustaceans, insects, microorganisms, etc.
Derived from natural products produced by deacetylation of
So that this chitosan may be covered over its surface or
Wood-based materials adhered or carried on the surface by rubbing or the like have the advantage of high safety. In addition,
The amino group content of chitosan is the aldehyde of the aldehydes
Since it is processed to be 2 to 20 times the base amount,
There is an advantage that the processing cost does not increase.

[Brief description of the drawings]

FIG. 1 is a bar graph showing formaldehyde emission (%) by each treatment of Example 1.

Continuation of the front page (56) References JP-A-57-98304 (JP, A) JP-A-62-183305 (JP, A) JP-A-5-245807 (JP, A) JP-A-62-186939 (JP, A) JP-A-3-293033 (JP, A) JP-A-7-227808 (JP, A) JP-A-7-148711 (JP, A) JP-B-7-110484 (JP, B2) (58) Surveyed field (Int.Cl. ⁶ , DB name) B27K 3/34-3/52 B21J 20/24

Claims (2)

(57) [Claims] 1. A deacetizing solution, which is in the form of a solution, is applied to the surface of a wood-based material produced using an adhesive containing aldehydes.
Chitosan having a degree of chilling of 30% or more has the amino group content described above.
2 to 20 times the amount of aldehyde groups in aldehydes
Dry after applying or spraying
Covers the surface of the wood-based material with this chitosan
A method for suppressing the emission of aldehydes from wood-based materials, characterized in that the aldehydes are attached or supported as described above. 2. The surface of a wood-based material produced using an adhesive containing aldehydes has a particle size of 20 per se.
0 μm or less in powder form having a deacetylation degree of 30% or more
Chitosan is converted to an aldehyde having an amino group content of
Rub it in 2 to 20 times the amount of aldehyde group
Alternatively, a method for suppressing emission of aldehydes from a woody material, wherein the method is applied or carried by spraying .