JP2000301667A - Sheet for plywood and the like and packing and storing method for plywood using the sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a formaldehyde emission amount by impregnating a perme able sheet-shaped non-woven fabric with a mixed binder composed of a chemical adsorbent provided with the formaldehyde adsorption function and a chemical binder at the specified dry weight ratio and fixing a specified dry adhesion amount of the chemical adsorbent thereon. SOLUTION: A permeable sheet-shaped non-woven fabric is impregnated with a mixed binder composed of a chemical adsorbent provided with the formaldehyde adsorption function and a binder at the 1:0.2-1:0.5 dry weight ratio, and the chemical adsorbent of 5-30 g/cm2 dry adhesion amount is impregnated and fixed thereon. Namely the chemical adsorbent 2 of fine powdery shape is fixed on the surface of a breathable sheet-shaped non-woven fabric constituting fibers 1 by an emulsion type binder to form a sheet used for plywoods. As a base of the sheet, a pulp fiber mixed non-woven fabric formed of crimpy fibers and pulp fibers forming the binder mixed together is used. The binder is composed of a synthetic resin or a rubber. The chemical adsorbent is composed of an amine, a hydrazide, a urea or others.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improved wood such as plywood (plywood), flaked board (particle board), fiberboard (fiberboard), laminated wood (laminated wood) and flooring materials using these. (Hereinafter simply referred to as “plywood”) A sheet for plywood that reduces the amount of formaldehyde released from plywood by adsorbing free formaldehyde inherent in the plywood before putting it on the market, and packing and storage of plywood using the same It is about the method.

[0002]

2. Description of the Related Art Such plywood is used for various purposes such as interior and exterior materials of buildings, structural materials for furniture such as storage furniture and cabinets. However, most plywood adhesives are synthetic resin adhesives such as urea resin (urea resin), melamine resin, resorcinol resin, and phenol resin, and almost all of them are condensates with formaldehyde. Due to the release of formaldehyde in the plywood as it reacts and the thermal decomposition and hydrolysis of the synthetic resin adhesive, toxic and strongly irritating formaldehyde (HCHO) is released from the plywood and emitted for a long time. .

[0003] To prevent the emission of formaldehyde from plywood, synthetic resin adhesives have been improved. However, not only are there problems with adhesive strength and cost, but also the plywood is made of wood. Since formaldehyde is emitted, it has been difficult to reduce the amount of formaldehyde released from plywood in a short period of time.

[0004] For this reason, in the case of a newly-built building or a house using plywood, in combination with the recent high airtightness and high insulation structure of the living space, formaldehyde emitted from the plywood contaminates indoor air and adversely affects the human body. (Sick house syndrome) is a social problem. In particular, this problem is remarkable in plywood (including ordinary plywood and special plywood) in which the amount of the synthetic resin adhesive used is larger than other plywoods.

According to the JAS standard, this plywood is F1 plywood (0.5 mg / l or less), F2 plywood (5 m or less) based on the amount of formaldehyde released from the synthetic resin adhesive used.
g / l or less) and F3 plywood (10 mg / l or less), and guidelines for the standard of the place of use are determined according to this classification. However, even in the recent high airtight and high heat insulation structure, even if the F1 plywood with the lowest formaldehyde emission is used, it will not be ventilated for a long time, or under high temperature and high humidity conditions, it will be 1-2 years after construction. , The indoor formaldehyde concentration, the recently issued Ministry of Health guidelines 0.1mg / m
^It was difficult to make it less than ³ . The guideline value of the Ministry of Health and Welfare adopts the proposal of the guideline value of indoor concentration by the World Health Organization (WHO), and a formaldehyde concentration of 0.1 mg / m ³ is equivalent to about 0.08 ppm.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to reduce the amount of formaldehyde emission by pre-adsorbing formaldehyde contained in plywood before putting it on the market, and to expand the use area of plywood for indoor use. And to obtain plywood that can be used in closed spaces.

[0007]

The plywood sheet of the present invention comprises a sheet-shaped nonwoven fabric having air permeability and a dry weight ratio of a chemical adsorbent having a formaldehyde adsorption function and a binder of 1: 0.2 to 1.0. A mixed binder mixed at a ratio of 1: 0.5 is impregnated and fixed with a chemical adsorbent having a dry adhesion amount of 5 to 30 g / m ² .

According to this means, since the sheet is made of a non-woven fabric having air permeability, the mixed binder is uniformly impregnated in the thickness direction of the non-woven fabric sheet without unevenness, and a predetermined amount of the chemical adsorbent is fixed. Therefore, when sandwiched between at least each plate material of plywood, formaldehyde released from the synthetic resin adhesive in the plywood is adsorbed from both sides of the sheet.

In the present invention, the dry adhesion amount of the chemical adsorbent may be determined according to the amount of the synthetic resin adhesive used for the plywood (the amount of formaldehyde released from the plywood), and is 5 g / m ^2. a it can not be expected the adsorption effect is too as below, since the cost exceeds 30 g / m ² too much, as the scope, 5 to 30 g / m ^2, and more preferably is suitable 10 to 30 g / m ² .

When the mixing ratio between the chemical adsorbent and the binder is less than 0.2 in terms of dry weight ratio to the chemical adsorbent 1, it is difficult for the binder to fix the chemical adsorbent. When the plywood is packed, the chemical adsorbent tends to fall off. If it exceeds 0.5, the binder will cover the surface of the chemical adsorbent, and the adsorption performance of the chemical adsorbent will be reduced. As for 1: 0.2 ~
1: 0.5 is preferred, and more preferably 1: 0.2 to
1: 0.4.

The method for packing and storing plywood of the present invention may be performed by packing and storing the plywood sheet in a state where the plywood is laid in close contact with at least the upper and lower surfaces of the plywood. Then, a plurality of plywoods are packed and stored, or are packed and stored in a state where they are closely laid on the upper and lower surfaces or the entire circumference of the stacked plywood sandwiched between the respective plate materials. . Therefore, between the time the plywood is manufactured and the time it is put on the market and used, the formaldehyde emitted from the plywood is efficiently adsorbed by the sheet, and plywood with a small amount of formaldehyde emission can be easily obtained.

In another aspect of the present invention, there is provided a method for packing and storing plywood, wherein the plywood sheet is packed with at least a plurality of plywood sandwiched between respective plate materials with a binding band or the like. It is stored under the condition that formaldehyde in the adhesive of plywood is released. In this case, the packing state of the plywood is more preferably such that the entire periphery of the stacked plywood is covered with the sheet of the present invention. Therefore, formaldehyde contained in the plywood is positively released and released quickly, and the sheet immediately absorbs the released formaldehyde, so that plywood with a small amount of formaldehyde released can be obtained in a shorter time.

In the present invention, storage under the condition that formaldehyde in the adhesive is released means that the adhesive is stored in a constant temperature room with a constant temperature or a constant temperature / humidity room with a constant temperature and humidity. And humidity are determined according to the type of plywood and the type of adhesive used, for example,
In the case of plywood, a temperature of 35 to 40 ° C is appropriate,
An appropriate humidity is 50 to 80%.

[0014]

Embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the sheet S for plywood of the present invention has a fine powdered chemical adsorbent 2 coated with an emulsion type binder on the surface of constituent fibers 1 of a sheet-like nonwoven fabric having air permeability. It is fixed.

As a base material of the sheet S, a fiber length of 3 to
A 5 mm crimped fiber and a pulp fiber serving as a binder are mixed and formed into a paper by a wet method.
A pulp fiber mixed nonwoven fabric of 00 g / m ² was used.

In this case, the reason why fibers having a fiber length of 3 to 5 mm and having crimps are used is that a sheet-type nonwoven fabric which is air-permeable and easily impregnated with a chemical adsorbent and a binder can be obtained by a wet method. However, when using another method, the present invention is not limited to this. Further, instead of the pulp fiber serving as a binder, a composite type (sheath-core type, parallel type) heat-fused fiber having a fiber length substantially equal to the above fiber length may be used. In addition, a nonwoven fabric composed of other fibers in a dry system can also be used as long as the composition is air-permeable and easily impregnated with the chemical adsorbent mixed binder. Further, as a method of fixing the chemical adsorbent and the binder, the mixed binder is sprayed on the nonwoven fabric by a spray method and then dried, but instead of the spray method, immersion, coating or the like may be used.

The basis weight of the nonwoven fabric as the base material is generally 5
0 to 150 g / m ² is sufficient, and when more strength is required, 150 to 300 g / m ² is preferable, and 50 to 300 g depending on the strength required as a product.
/ M ² .

If the binder is an emulsion type, it may be a synthetic resin (for example, polyacrylate, acrylic / styrene copolymer, polyvinyl acetate, vinyl acetate / ethylene copolymer, vinyl acetate / acrylic). Copolymers, polyethylene, polyvinyl chloride, epoxy, etc.) but also rubber-based (eg, natural rubber, polybutadiene,
Butadiene, SBR latex, NBR latex, etc.)
However, an emulsion type in which polymer particles are dispersed in water is preferable because the nonwoven fabric can be easily impregnated.

The range of the mixing ratio of the chemical adsorbent and the binder of the mixed binder is as follows:
0.2 to 1: 0.5 is preferred, and more preferably 1:
Although it is in the range of 0.2 to 1: 0.4, when the amount of the binder is increased within the above range in order to increase the retention of the chemical adsorbent, the binder surface after drying becomes porous. Synthetic resin-based resins are preferred.

The dry adhesion amount of the chemical adsorbent is determined by JAS
Standard for F2 plywood, 1 for E1 particle board
Was prepared in 5 g / m ^2, depending on the amount of formaldehyde that is dissipated from the plywood such 5 to 30 g / m ^2, more preferably in the range may be determined in the range of 10 to 30 g / m ^2.

As the chemical adsorbent used in the present invention, known chemical adsorbents such as amine type, hydrazide type, urea type and the like, and those obtained by spreading various chemical substances on these to enhance the adsorption function may be used. it can. This type of material is commercially available and chemisorbs formaldehyde via amino groups.

As shown in FIG. 2, the packing / storage method of the present invention is as follows. A sheet S is sandwiched between a plurality of plywoods P and stacked, and the upper and lower surfaces of the stacked plywoods P are stacked. After covering with the sheet S, it was bound and packed by the binding band B. Then, although not shown in the drawing, it was stored for a predetermined period in a constant temperature room in which the temperature was adjusted within a certain range.

As another method, as shown in FIG. 3, sheets S are sandwiched between a plurality of plywoods P and stacked.
After the periphery of the stacked plywoods P was covered with the sheet S, the plywoods P were tied with the tying band B and packed. Then, although not shown in the figure, the container was housed in a cardboard box and stored in a constant temperature room in which the temperature was adjusted within a certain range for a predetermined period.

By the way, as a condition for releasing formaldehyde in the adhesive of the plywood, a constant temperature room is used, and for plywood, the temperature is set to about 35 to 40 ° C., and the temperature is set to about 2 to 6 days.
After seasoning for days, if it is lower than 35 ° C., the release rate of formaldehyde becomes slow, and if it exceeds 40 ° C., the plywood is deformed (warped).

In this case, the above conditions are not limited to a constant temperature room, but may be any room that can control the temperature or the temperature and humidity. Optimal conditions for releasing and releasing formaldehyde contained in the plywood in a short time without deformation of the plywood may be determined according to the type of the plywood and the type of the adhesive used.

[0027]

EXAMPLES Examples of the sheet for plywood of the present invention will be described below, but the present invention is not limited thereto.

Fiber length 3-5 mm, number of crimps 15-20
/25.4mm, 50% of 3 denier polyester fiber
Was mixed with 50% of pulp fiber to prepare a nonwoven fabric sheet having a thickness of 2.5 mm and a basis weight of 200 g / m ² by a wet method. Next, a formaldehyde adsorbent (trade name: Shuklens KD311) was added to the nonwoven fabric sheet by weight / solid ratio.
G, manufactured by Rasa Kogyo Co., Ltd.) and 100 parts of acrylic emulsion binder (trade name: Ultrasol N38K, manufactured by Ganz Chemical Co., Ltd.)
After spraying a mixed synthetic resin solution in which 30 parts and water are adjusted to a concentration of 20% by a spray method, a drying treatment is performed so that a dry adhesion amount is 18 g / m ² (formaldehyde chemical adsorbent amount is 13.8 g / m ² ). Thus, a desired sheet for plywood was produced.

Next, F1 plywood (width 20 cm × length 30 c)
(M × 1.2 cm thick), the plywood sheets of the above embodiment were sandwiched between the respective sheet materials, stacked and bound by a binding band, and a packaged product by a conventional method. And
It was stored in a constant temperature room (set temperature: 40 ° C.) for 72 hours. In addition,
The package according to the conventional method is one in which plywood is simply stacked and bound by a binding band.

After the above-mentioned storage period has elapsed, the intermediate products are taken out one by one from each packaged product, and a modified F1 plywood product (product of the present invention) using the plywood sheet of the embodiment and a conventional method are used. Each of the F1 plywood (referred to as a conventional product) is housed in a sealed container (Tedlar bag), 10 liters of fresh air is injected, and a formaldehyde concentration (ppm) in the container at each elapsed time is detected by a tube type gas measuring instrument ( (Made by Gastec)
As a result, the results shown in Table 1 were obtained.

[0031]

[Table 1]

From the results in Table 1, it can be seen that, according to the present invention, the formaldehyde present in the plywood is adsorbed and a modified plywood product in which the formaldehyde emission is reduced to about 1/12 compared to the conventional product is obtained. That was confirmed.

Next, 7 sheets of the modified F1 plywood (product of the present invention) obtained in the above example and 7 sheets of the F1 plywood (conventional product) obtained by the conventional method were respectively placed in a 1 m ³ closed space. Then, the formaldehyde concentration (ppm) in the closed space at each elapsed time was measured by a detector tube type gas meter (manufactured by Gastech Co., Ltd.), and the results in Table 2 were obtained.

[0034]

[Table 2]

As is clear from the results shown in Table 2, the product of the present invention has a formaldehyde emission of 1/15 as compared with the conventional product.
It was confirmed that a reduced plywood was obtained.

When the interior of a room having a size of 13 m ^{2 and a} space of 32.5 m ³ using the modified F1 plywood product of the present invention was shut down and the formaldehyde concentration in the room was measured 24 hours later, it was found to be 0.03 ppm. there were. The average temperature in the room was 25 ° C. and the average humidity was 60%. From this, according to the present invention, the indoor formaldehyde concentration was adjusted to 0.08 pp which is the guideline value of the Ministry of Health and Welfare.
m or less.

[0037]

According to the plywood sheet of the present invention,
It can be used as a packaging material for plywood and can adsorb unreacted formaldehyde and formaldehyde released from the synthetic resin adhesive in the plywood, so that plywood with reduced formaldehyde emission can be easily obtained. be able to.

Further, when the method for packing and storing plywood of the present invention is used, the formaldehyde emitted from the plywood is efficiently adsorbed by the sheet between the time the plywood is manufactured and the time it is put on the market and used. Plywood with reduced formaldehyde emission can be easily obtained in a short period of time, and the places where the plywood is used can be expanded.

Further, the sheet for plywood according to the present invention comprises:
By laying on the upper surface of plywood used as a building material before moving in, it can be used as a kind of curing sheet of plywood, and it is further cut into a suitable size, and a structure made of plywood (tableware) By laying inside of shelves, storage furniture, cabinets), formaldehyde emitted from plywood can be adsorbed, and the enclosed space can be improved to a clean air environment.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view showing a sheet for plywood of the present invention.

FIG. 2 is a perspective view showing an embodiment of the present invention.

FIG. 3 is a partially broken perspective view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Constituent fiber 2 ... Chemical adsorbent B ... Bundling band P ... Plywood S ... Plywood sheet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E037 AA20 BA09 BB11 BC10 CA05 4F100 AJ02 AK25 AK41 AP02B AP02C AS00A BA03 BA06 BA10B BA10C BA13 CA30A DG01 DG15A EJ82A GB08 GB90 JD02A JM01 YY00A

Claims (3)

[Claims] 1. A sheet-like nonwoven fabric having air permeability is impregnated with a mixed binder obtained by mixing a chemical adsorbent having a formaldehyde adsorption function and a binder at a dry weight ratio of 1: 0.2 to 1: 0.5. , Dry adhesion 5-30 g / m
^A sheet for plywood, wherein the chemical adsorbent of item ² is fixed. 2. A method for packing and storing plywood, wherein the plywood sheet according to claim 1 is sandwiched between at least each plate material to pack and store a plurality of plywood. 3. A sheet for plywood according to claim 1, which is sandwiched between at least each plate material to pack a plurality of plywood, and then under a condition in which formaldehyde in an adhesive of the plywood is released. A method for packing and storing plywood, characterized by storage.