JP2007038661A - Aldehyde collector and manufacturing method of woody panel using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein an aldehyde collector is reacted with a formaldehyde type adhesive up to hot press molding when aldehyde collector is preliminarily added to the adhesive or a woody material in a case that the aldehyde collector is used in order to remove formaldehyde when a woody panel is manufactured using the woody material and the adhesive and the curing of the aldehyde collector due to hot pressing becomes insufficient to cause the lowering of the strength of the woody panel. <P>SOLUTION: The aldehyde collector contains an aldehyde collecting composite. This aldehyde collecting composite is composed of a powder or granule of at least one kind of an aldehyde collecting compound or a lump comprising a powder or granule of a plurality of aldehyde collecting compounds and an outer coating material for coating at least a part of the outer surface of the powder, granule or lump of the aldehyde collecting compound. The outer coating material comprises an aldehyde collecting agent having no reactivity with respect to aldehydes and the aldehyde collecting compound being a polymeric compound or wax with a melting point of 40-140°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aldehyde collector for collecting and removing aldehydes such as formaldehyde, and more specifically, an aldehyde used for producing a wood board by bonding a wood material using a formaldehyde adhesive. It relates to a kind collecting agent. Moreover, it is related with the manufacturing method of the wooden board using this.

  In the production of wood boards such as particle board, plywood and wood fiber board, a formaldehyde adhesive (phenol resin, urea resin, melamine resin) or the like may be used as an adhesive. In this case, the formaldehyde released from the formaldehyde-based adhesive is released into the atmosphere from the wooden board, which has a problem of harming the environment and health.

Conventionally, as a means for solving this problem, urea, sulfite, and hydrazides are applied to the surface of a wood material as a so-called formaldehyde collector that reacts with formaldehyde and collects it (Patent Document 1). , See Patent Document 2). In this case, the formaldehyde scavenger is usually diluted with water and applied by spray coating, roll coating or the like. The wooden boards are stacked, stored and shipped after applying the formaldehyde scavenger.
Japanese Patent Laid-Open No. 11-240002 JP 2002-331504 A

By the way, the wooden board is usually shipped after thinly polishing the surface in order to improve the surface aesthetics and to obtain the required dimensions after applying the aldehyde scavenger, In particular, when the polishing thickness is large, the amount of aldehydes collecting agent present on the surface of the wooden board is also reduced, and as a result, the above-described means has a problem that the ability to collect formaldehyde is reduced or eliminated. As means for solving this problem, a method has been proposed in which sodium sulfite or urea is added as a formaldehyde-collecting component to a wood material to reduce the formaldehyde emission (Patent Document 3).
Japanese Patent Laid-Open No. 10-11010

  However, since the aldehyde collection component contained in the aldehyde collection agent reacts with and absorbs formaldehyde, the aldehyde collection is performed before hot pressing, that is, in the state where the adhesive is uncured and is present in the wood material. When the collector is added, it reacts with formaldehyde in the adhesive, which inhibits the curing by hot pressure and lowers the strength of the wood board. Another problem is that many of the compounds for collecting aldehydes disappear before hot-press molding, and the ability to collect formaldehyde from the wooden board after hot-press molding is reduced.

  Therefore, in the present invention, when a wood board is manufactured by bonding a wood material with a formaldehyde-based adhesive, the adhesive does not react with the adhesive component while suppressing release of aldehydes and until hot pressing. It is an object of the present invention to provide an aldehyde scavenger that can suppress the performance degradation of the wood, and to provide a method for producing a wood board using these to suppress the release of aldehydes and the strength reduction.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, collected aldehydes having a powder or granular compound for collecting aldehyde as one or a plurality of lumps and the outer surface of which is coated with an outer covering. Aldehydes-collecting agent containing a composite for the main component, but the jacket is a polymer compound or wax having a melting point of 40 to 140 ° C., and for collecting aldehydes and aldehydes By not having reactivity with the compound, sufficient aldehyde collection ability can be exhibited for the first time in the hot pressing process, that is, it does not hinder the ability of the adhesive until hot pressing. It discovered that it could be set as an aldehydes collection agent, and came to this invention.

  The present inventors have also found that paraffin wax, microcrystalline wax, hydrogenated oil and polyethylene wax having a melting point of 50 to 120 ° C. are particularly suitable compounds.

  The aldehyde-collecting agent of the present invention covers the outside of the compound for collecting aldehydes with an outer covering, so that it can be added to a wood material before hot pressing together with a formaldehyde-based adhesive, It is unlikely that the active adhesive component disappears upon reaction. On the other hand, at the time of hot-pressure molding, the outer shell is melted and liquefied to release the aldehyde-collecting compound, so that the emission of formaldehyde from the wooden board after hot-pressure molding can be effectively suppressed.

  In addition, since the outer covering has little reaction with the adhesive before curing, it is possible to produce a wood board that has little inhibition of curing and hardly loses strength even after hot pressing. Therefore, when manufacturing wooden boards such as particleboard, MDF, and plywood using formaldehyde adhesives, the aldehyde collector according to the present invention is added to and dispersed in wooden materials or adhesives. The wood board obtained by the above method has a low formaldehyde emission amount regardless of the presence or absence of surface polishing, and has a low strength reduction.

(Aldehyde collector)
The aldehyde collector according to the present invention is used to remove aldehydes generated from an adhesive when a wooden board is produced by adhering a wooden material using a formaldehyde-based adhesive. It is added and dispersed in the agent. The aldehyde collection agent of the present invention is not composed of a powdery or granular aldehyde collection compound itself, but is composed of a compound for collecting aldehydes consisting of the aldehyde collection compound itself and an outer cover. It is what has been. However, as will be described later, it is not necessary to be constituted only by the aldehydes-collecting composite.

(Cover)
The outer covering used in the present invention is a polymer compound or wax having a melting point of 40 to 140 ° C., and has no reactivity with aldehydes and the aldehyde-collecting compound. Any compound having such properties can be used. As long as it has such properties, it may be composed of one kind of compound or a plurality of compounds.

  Specifically, examples of the polymer compound include polyethylene glycol. On the other hand, as waxes, natural wax such as carnauba wax, candelilla wax, montan wax, ceresin, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, α-olefin wax, Fischer-Tropsch wax, synthetic fatty acid Synthetic waxes typified by esters can be mentioned. Examples thereof also include oxidized waxes obtained by oxidizing these natural waxes and synthetic waxes, hydrogenated hardened fats and oils (for example, beef tallow hardened oil and castor wax), and modified wax derivatives. Furthermore, waxes made of olefin and maleic anhydride, waxes made of olefin and acrylic acid, waxes made of vinyl acetate or waxes such as higher alcohols, fatty acid amides and polyethers can also be used.

  Among these, a compound having a melting point of 40 ° C. to 140 ° C. is preferable, and paraffin wax, microcrystalline wax, oil-hardened oil, and polyethylene wax having a melting point of 50 ° C. to 120 ° C. are more preferable. If the melting point is lower than 40 ° C, there is a risk that the mechanism that melts without applying heat and melts and dissipates at the time of hot pressing may not be achieved in summer. This is because, similarly, a mechanism for melting and diffusing is hardly achieved. Furthermore, when paraffin wax and microcrystalline wax, oil and fat hardened oil, polyethylene wax having a melting point of 50 ° C. to 120 ° C. are melted at the time of hot press molding, it is easy to release the included aldehyde-collecting compound, This is because the melted wax also acts as a water-repellent compound and can prevent water absorption of the wood board.

(Compound for collecting aldehydes)
The compound for collecting aldehydes may be any compound that is in the form of powder or particles at room temperature and has a known ability to collect aldehydes that react with aldehydes. Examples of preferred compounds include sulfites, bisulfites, ureas, hydrazides and the like.

  Examples of sulfites include metal salts such as sodium sulfite, potassium, calcium, and magnesium, amine salts such as monoethanolamine, ammonium salts, and double salts thereof. From the viewpoint of low cost, sodium sulfite, potassium sulfite, ammonium sulfite and calcium sulfite are preferable.

  Bisulfites include bisulfite, pyrosulfite and dithionite. Examples of the salt include metal salts such as sodium, potassium and magnesium, amine salts such as monoethanolamine, ammonium salts and the like. Of these, sodium salts and potassium salts are preferred.

  Examples of ureas include urea and compounds having a urea bond, such as methylurea, ethylurea, dimethylurea, diethylurea, guanylurea, acetylurea, thiourea, and cyclic ureas such as ethyleneurea and allantoin. Examples include condensates and acyclic urea condensates such as urea dimers such as biuret. In the present invention, one or two or more of these ureas can be used in combination. Among these, preferable examples include urea, ethylene urea, and thiourea, and urea is preferable from the viewpoint of price.

  Examples of the hydrazides include a monohydrazide compound having one hydrazide group in the molecule, a dihydrazide compound having two hydrazide groups in the molecule, and a polyhydrazide compound having three or more hydrazide groups in the molecule. it can. Specific examples of the monohydrazide compound include alkyl hydrazide compounds such as lauric acid hydrazide, salicylic acid hydrazide, form hydrazide, acetohydrazide, propionic acid hydrazide, and naphthoic acid hydrazide. Specific examples of dihydrazide compounds include carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide dihydrazide dihydrazide, maleic acid dihydrazide dihydrazide dihydrazide And dibasic acid dihydrazides such as malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, and dimer acid dihydrazide. Specific examples of the polyhydrazide compound include polyacrylic acid hydrazide. Among these, dibasic acid dihydrazide compounds are preferable, carbodihydrazide, adipic acid dihydrazide, and dodecanedioic acid dihydrazide are more preferable, and adipic acid dihydrazide is more preferable from the viewpoint of price and availability. In the present invention, one or more of these hydrazides can be used in combination.

  Among such compounds for collecting aldehydes, those which are solid at room temperature but have a property of generating sulfurous acid gas upon heating are preferable. If it is a compound having such properties, sulfur dioxide gas having an ability to collect aldehydes is generated in the hot-pressure molding process, and the aldehydes are removed by reacting in a gaseous state with aldehydes such as formaldehyde. This is because a higher aldehyde collection ability can be exhibited than when a compound having another aldehyde collection ability that removes aldehydes by a solid-gas reaction is used.

It is presumed that the compound that generates sulfur dioxide gas from the heating collects aldehydes by following the following chemical reaction. The case where formaldehyde is used as the aldehyde and sodium hydrogen sulfite is used as the aldehyde collecting compound will be described as an example.
2NaHSO ₃ → (Heating) → Na ₂ SO ₃ + H ₂ O + SO ₂ ↑
HCHO + SO ₂ + H ₂ O → HOCH ₂ SO ₃ H—generates unstable acid HOCH ₂ SO ₃ H + Na ₂ SO ₃ → HOCH ₂ SO ₃ Na + NaHSO ₃

  Examples of the compound for collecting aldehydes having the above properties include bisulfites such as sodium hydrogen sulfite. Among the bisulfites, bisulfite and pyrosulfite. Dithionite and the like are preferable. Examples of the types of the salts include metal salts such as sodium, potassium and magnesium, amine salts such as monoethanolamine, ammonium salts and the like. Moreover, even if it is sulfites, salts, such as magnesium sulfite, zinc sulfite, and aluminum sulfite, are solid at normal temperature, and have the property to generate sulfite gas by heating.

(Compound for collecting aldehydes)
A compound in which at least a part of the outer surface of the powdery or granular aldehyde-collecting compound is coated with the jacket is the aldehyde-collecting composite according to the present invention. In the aldehyde collection compound, it is preferable that each powder or each particle of the aldehyde collection compound is individually included, but in a state where a collection of a plurality of powders or particles is made into one lump, The outer side may be coated.

  Further, it is most preferable that the outer covering completely covers the outer surface of the compound powder for collecting aldehydes, particles or a lump, and the compound for collecting aldehydes completely covers the outer covering. The effect of the present invention can be obtained even if at least part of the coating is covered. This is because it is sufficient to have a function of reducing the contact portion with the adhesive in an uncured state before hot pressing. Therefore, it may be a composite for collecting aldehydes in which a part of the compound for collecting aldehydes appears on the outside.

  The compound for collecting aldehydes and the outer covering contained in the aldehyde collecting agent as a composite for collecting aldehydes is 20/80 to 95/5 in weight ratio when averaged over the whole aldehyde collecting agent. It is preferably contained in a ratio, and more preferably in a ratio of 40/60 to 90/10. When the number of aldehydes-collecting compounds is less than 20, the aldehydes-collecting ability is lowered, and the number of particles of only the envelope that does not include the aldehydes-collecting compounds also increases. On the other hand, when the amount exceeds 95, the amount of particles containing only the aldehyde-collecting compound is excessively increased, which is substantially the same as the case of mixing. However, in the individual aldehydes collection composite, there may be one exceeding the above ratio range.

  The aldehyde-collecting compound and the outer covering used in the aldehyde-collecting compound can be selected from one of the above-mentioned compounds, but a plurality of types can be selected for each aldehyde. It can also be set as the composite for collection.

  The average particle diameter of the composite for collecting aldehydes is preferably 2 mm or less, and more preferably 1 mm or less. This is because when the average particle size is large, it becomes difficult to uniformly disperse in the wood material, and it tends to remain as white spots on the surface of the wood board.

(Other additives)
In the aldehyde collection agent of the present invention, in addition to the aldehyde collection compound, as necessary, in addition to antioxidants, preservatives, colorants, rust inhibitors, necessary in the manufacturing process. Additives such as powder fluidity improvers such as chemicals such as carbonates, silicates, and aluminosilicates may also be included. In particular, in the case of having a compound such as bisulfite that collects aldehydes with sulfurous acid gas in the hot pressing process, a base such as ammonia is used in the hot pressing process to remove unreacted sulfurous acid gas. It is preferable to contain a compound such as urea that generates a reactive gas.
Furthermore, in the aldehydes collecting agent of the present invention, an ionic polymer such as polyacrylic acid, polymethacrylic acid, acrylic acid-maleic acid copolymer is used in order to improve the coverage of the compound for collecting aldehydes. Compounds and their metal salts, fatty acids such as oleic acid, stearic acid, lauric acid, and salts thereof are interposed between the jacket used in the present invention and the compound for collecting aldehydes to obtain aldehydes. It can also be set as the composite for collection. These inclusions are particularly effective when the affinity between the aldehyde-collecting compound and the envelope is poor and coating is difficult.

(Production method of aldehyde collector)
The aldehyde collection agent in the present invention can be produced by coating the aldehyde collection compound with the jacket. For the manufacturing method, known coating techniques can be used. For example, as a chemical manufacturing method, in addition to an interfacial polymerization method in which a polymer is polymerized at the interface between a compound for collecting aldehydes and a dispersion medium, an in-situ polymerization method, curing in liquid Examples thereof include a coating method.

  Also, as a physicochemical method, heating and dispersing in a poor solvent that does not dissolve both the compound for collecting aldehydes and the envelope, and melting the envelope to include the compound for collecting aldehydes In addition to the cooling method, a method of separating layers from an aqueous solution, a method of separating layers from an organic solvent, a submerged drying method, and the like can be given.

  Examples of the mechanical method include a spray-drying method in which a compound for collecting aldehydes is dispersed in a solvent containing an outer covering and spray-dried to coat, an air suspension coating method, a dry mixing method, and the like. It is done.

In the case of producing an aldehyde-collecting agent as described above, a solvent, a method, or the like that is appropriately used may be selected according to the properties of the aldehyde-collecting compound and the outer covering. Among these coating techniques, as a simple and inexpensive method for mass production, a compound for collecting aldehydes is dispersed in a melted outer jacket, cooled and solidified, and then pulverized and for collecting aldehydes. A method of dripping or spraying the outer shell in a molten state into the compound to coat the compound for collecting aldehydes and solidifying in a particulate form is preferable.
In this case, in consideration of production efficiency, it is preferable to melt, drop, or spray the outer covering at a temperature 1 to 20 ° C., preferably 5 to 10 ° C. higher than the melting point of the outer covering. Thereafter, the aldehyde scavenger of the present invention can be produced by cooling to a temperature 10 ° C. or more, preferably 20 ° C. or more lower than the melting point of the outer covering.

(Wood board manufacturing method)
In order to manufacture a wooden board using formaldehyde adhesive, generally, after adding formaldehyde adhesive to the wood material (adhesive addition process), the process of bonding the wood material by heating while applying pressure (heat) (Press molding process) When producing a wood board using the aldehydes collecting agent of the present invention, the aldehyde collecting agent produced by the above method is used in the formaldehyde adhesive prior to the adhesive adding step. It can also be used by adding to the side of the wood material to be bonded before, after or simultaneously with the addition of the adhesive.

  For example, when producing a particle board (hereinafter abbreviated as PB), a relatively finely pulverized wood material is used for the front and back layers, and a relatively coarsely pulverized wood material is used for the core layer. use. After the formaldehyde adhesive is spray-added into the wood material for the front and back layers, the aldehyde scavenger of the present invention is added and dispersed. For the core layer, an adhesive and an aldehyde collector are similarly added. The aldehyde collector that is added to the front and back layers and the aldehyde collector that is added to the core layer may be the same or different, but the aldehyde collector used for the front and back layers is the surface of the wooden board. What does not impair the aesthetics is desirable. On the other hand, it is desirable that the aldehyde collector used for the core layer has a high ability to collect aldehydes. The order of addition of the aldehyde collecting agent is not particularly limited, either directly added to the adhesive, or before, after or simultaneously with the addition of the adhesive. It is desirable in the process to add an agent.

Then, it laminates | stacks on a surface layer-core layer-back layer, and heats it. In general, hot-press molding is performed while applying pressure. The wood material is bonded by hot pressure to form a wood board. The temperature and time of the hot pressing process are appropriately determined depending on the quality and productivity of the wood board to be produced, but when using the aldehydes collecting agent of the present invention, the hot pressing temperature is 100 to 300 ° C. Preferably, 140-250 degreeC is more preferable. The hot pressing time is preferably 60 seconds or longer, more preferably 90 seconds or longer. If the temperature is low and the time is short, the temperature inside the wooden board is difficult to rise, the outer covering containing the compound for collecting aldehydes is insufficiently melted, and the ability to collect aldehydes is lowered. In addition, when the compound for collecting aldehydes has a property of generating sulfurous acid gas by heating, the amount of sulfurous acid gas generated is small and the ability to collect aldehydes is reduced. On the other hand, if the temperature is too high, the quality of the wood board will be burnt, and the quality will deteriorate.
In the case of the aldehyde collector of the present invention, the aldehyde collector does not come into contact with the adhesive or very little until the wood board is heated in this hot press molding process. It does not hinder the performance of the adhesive in the pressure molding process. In addition, also when manufacturing a wood fiber board (MDF), the said aldehydes collection agent can be added similarly and a wood board can be manufactured.

  The addition amount of the aldehyde collector in the wood material in the production of the wood board is 0.1 to 20.0% by weight, preferably 0.5 to 10% by weight, more preferably 1.0 to 7.0% by weight. It is. If the amount added is less than 0.1% by weight, the desired collection ability cannot be obtained. This is to lead to an increase in cost.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only the following Examples. In each example, unless otherwise specified, parts and% are based on mass.

(Example 1)
(Manufacture of aldehydes collector)
15 parts of sodium sulfite, 15 parts of paraffin wax (melting point: 75 ° C.) and 100 parts of toluene were weighed into a Kolben and heated to 120 ° C. in a nitrogen atmosphere to melt the paraffin. After melting, the mixture was gradually cooled to room temperature while stirring at 300 rpm, 30 parts of ethyl acetate was added and further stirred to disperse the product. After the product was filtered with suction, the solvent remaining in the product was washed by replacement 4-5 times with methanol. The filtered product was taken out, washed with stirring in ion-exchanged water, and then filtered again three times. Finally, the water was replaced with methanol, and the composite for collecting aldehydes obtained as a filtered product was taken out at room temperature. To obtain 21.5 parts of an aldehyde scavenger.

  FIG. 1 shows an enlarged photograph of the aldehyde collecting compound constituting the aldehyde collecting agent prepared as described above, and FIG. 2 shows an enlarged photograph of the sodium sulfite particles used as the aldehyde collecting compound. In FIGS. 1 and 2, a scale is shown in the photograph in order to show the size of the particles. 1 and 2, it can be seen that crystalline sodium sulfite is coated with paraffin wax and the crystal surface does not appear outside.

(Production of wood board)
Wood raw materials such as wood chips are pulverized with a flaker, and sieved with a sieve having an opening size of 1.7 mm. did. The sieved woody material was dried in a hot air dryer at 90 ° C. to make the water content 3% or less. Next, urea resin (non-volatile content 65%, urea: formaldehyde = 1: 1.2 mol) was used as an adhesive, and 55% wax emulsion, ammonium chloride and water as curing agents, 20 parts, 1 part, 0 parts, respectively. .5 parts and 2 parts were mixed (hereinafter referred to as "mixture A").

25 parts of the mixture A was spray-coated on 100 parts of the wood material for the front and back layers, and mixed uniformly. Thereafter, the aldehyde-collecting agent prepared by the above method was added and mixed at the ratio shown in Table 1 to obtain a front and back layer material. Similarly, 15 parts of the mixture A and 100 parts of the wood material for the core layer were added with the aldehyde scavenger prepared by the above method to obtain a core layer material. Next, 250 parts of the back layer material, 650 parts of the core layer material, and 250 parts of the surface layer material are sequentially spread on a 30 cm square formwork, sandwiched between 200 ° C. hot plates and hot-pressed at a pressure of 40 kgf / cm ² for 90 seconds. A wood board having a thickness of 15.2 mm and a density of 0.77 g / cm ² was obtained. In addition, the particle diameter of the aldehydes collection agent used above was adjusted by sieving with a sieve having an opening size of 2 mm.

(Evaluation)
Formaldehyde emission amount, water absorption thickness expansion rate and bending strength test, peel strength test are in accordance with the test method for formaldehyde emission amount of particle board (JIS A 5908: 2003) and building boards (JIS A 1460: 2001). Measured. As for the appearance of the wood board, the surface of the wood board obtained after hot pressing was visually observed, and the quality was determined from the size and number of vitiligo. These evaluation results are shown in Table 1. In the table, the symbols in the appearance column have the following meanings.

Appearance: ◎ Good (no vitiligo) ○ Slightly fine vitiligo △ A lot of fine vitiligo
× There are large vitiligo ×× There are many large vitiligo

(Comparative Example 1)
A wood board was produced in the same manner as in Example 1 except that the aldehydes collector was not used. The obtained evaluation results are shown in Table 1.

(Comparative Example 2)
A wood board was prepared in the same manner as in Example 1 except that uncoated sodium sulfite was used as the aldehydes collector. The obtained evaluation results are shown in Table 1.

(Example 2)
(Manufacture of aldehydes collector)
After adding 50 parts of paraffin wax (melting point 75 ° C.) as a jacket to a stainless steel container and heating and melting it, 50 parts of sodium sulfite was added as a compound for collecting aldehydes while stirring. The mixture was gradually cooled while being stirred and dispersed. When stirring became difficult, stirring was stopped, and the mixture was quenched with ice water and solidified to obtain a lump of paraffin wax covering sodium sulfite. This was first ground to a size of 0.5 to 2 cm and then ground with an Ultra Centrifugal Mill (manufactured by Mitamura Riken Kogyo). Thereafter, the pulverized product was sieved with a sieve having an opening size of 2 mm to adjust the particle size to obtain an aldehyde-collecting composite, thereby obtaining an aldehyde-collecting agent. The enlarged photograph of the obtained aldehydes collection composite is shown in FIG. FIG. 3 also shows a scale in the photograph.

(Creation of wood board)
The wood board was produced by the method described in Example 1. The obtained evaluation results are shown in Table 2.

(Example 3 to Example 9, Comparative Example 3)
In the same manner as in Example 2, the outer covering was changed to produce an aldehyde-collecting agent. The wood board was produced by the same method as in Example 1. The obtained evaluation results are shown in Table 2 (Examples 3 and 4), Table 3 (Examples 5 to 7) and Table 4 (Examples 8 and 9 and Comparative Example 3).

(Example 10 to Example 13)
In the same manner as in Example 2, paraffin wax (melting point: 66 ° C.) was used as an envelope, and sodium sulfite was used as a compound for collecting aldehydes. The wood board was produced by the same method as in Example 1. The obtained evaluation results are shown in Table 5 (Examples 10 to 12) and Table 6 (Example 13).

(Example 14 to Example 17)
(Manufacture of aldehyde collectors)
As a compound for collecting aldehydes, 80 parts of sodium sulfite was placed in a household mixer and stirred. A hole with a diameter of about 2 mm is made in the upper part of the container, and 20 parts of the outer covering are melted and gradually dropped. In addition, since the shaft part of the stirring blade has heat, it was gradually dropped while cooling at any time to prepare an aldehyde-collecting agent. The particle size of the aldehydes collector was adjusted by sieving with a sieve having an opening size of 1 mm (Example 14), 2 mm (Example 15), 3 mm (Example 16) and 2 mm (Example 17). By using an aldehydes collection composite, an aldehydes collection agent was obtained. FIG. 4 shows an enlarged photograph of the aldehyde collection composite (Example 15) sieved with 2 mm of the obtained aldehyde collection composite. FIG. 4 also shows the scale in the photograph.

(Production of wood board)
The wood board was produced by the method described in Example 1. Table 7 shows the obtained evaluation results.

(Example 18 to Example 23)
(Manufacture of aldehyde collectors)
In the same manner as in Example 17, the aldehyde-collecting compound was changed to prepare an aldehyde-collecting agent. The particle size of the aldehydes collector was adjusted by sieving with a sieve having an opening size of 2 mm.

(Production of wood board)
The wood board was produced by the method described in Example 1. The obtained evaluation results are shown in Table 8 (Examples 18 to 20) to Table 9 (Examples 21 to 23).

  From the above examples, it can be seen that when the present invention is carried out using bisulfites, particularly as aldehydes-collecting compounds, the amount of formaldehyde emitted is low and the strength is reduced.

  The aldehyde collector of the present invention has industrial utility as an additive added to a wood material or an adhesive when the wood material is bonded with a formaldehyde-based adhesive. The wood board manufacturing method of the present invention has industrial applicability as a manufacturing method of particle board, plywood and wood fiber board with less formaldehyde emission and no strength reduction.

2 is an optically magnified photograph of a composite for collecting aldehydes used in the present invention produced by the method described in Example 1. FIG. It is an optical expansion photograph of the sodium sulfite particle | grains used as a compound for aldehydes collection. 2 is an optically enlarged photograph of a composite for collecting aldehydes used in the present invention produced by the method described in Example 2. FIG. It is an optical expansion photograph of the compound for collection of aldehydes used for the present invention produced by the method of Example 15.

Claims (11)

Aldehydes trapping agent used by adding and dispersing in wood materials or adhesives,
The aldehyde collection agent contains a compound for collecting aldehydes,
The composite for collecting aldehydes is:
At least a part of the outer surface of at least one kind of aldehyde-collecting compound powder or granule or a plurality of aldehyde-collecting compound powder or granule and the aldehyde-collecting compound powder, granule or mass Consisting of a jacket to cover,
The outer covering contains an aldehyde compound and a polymer compound or wax having no reactivity with the aldehyde-collecting compound and having a melting point of 40 to 140 ° C. Collection agent.   2. The outer covering includes one or more compounds selected from the group consisting of paraffin wax, microcrystalline wax, oil and fat hardened oil, and polyethylene wax having a melting point of 50 to 120 ° C. Aldehyde collectors   The abundance ratio of the compound for collecting aldehydes and the outer covering in the aldehyde-collecting agent is 20/80 to 95/5 in weight ratio, described in any one of claims 1 to 3. Aldehydes scavenger.   4. The aldehyde collecting agent according to any one of claims 1 to 3, wherein an average particle diameter of the composite for collecting aldehydes is 2 mm or less.   The said aldehyde collection compound contains 1 type, or 2 or more types of the compound which consists of a bisulfite, sulfite, urea, and the group of hydrazides, The claim in any one of Claims 1-4 characterized by the above-mentioned. Aldehyde collectors described in 1.   5. The compound according to claim 1, wherein the compound for collecting aldehydes is one or more compounds of the group of sodium hydrogen sulfite, potassium hydrogen sulfite, sodium pyrosulfite, or potassium pyrosulfite. An aldehyde-based scavenger described in that section. Melting a jacket having a property of being a polymer compound or wax having a melting point of 40 to 140 ° C. and not having reactivity with an aldehyde and a compound for collecting aldehyde; and in the melted jacket A step of dispersing and charging a powdered or granular compound for collecting aldehydes, a step of cooling and solidifying the outer cover in which the compound for collecting aldehydes is dispersed, and the solidified outer cover Collecting aldehydes in which at least a part of the outer surface of a lump composed of powder or particles of the aldehyde-collecting compound or a plurality of powders or particles of the aldehyde-collecting compound is coated with the outer covering And a step of obtaining a composite for use. A step of melting an outer covering which is a polymer compound or wax having a melting point of 40 to 140 ° C. and has no reactivity with an aldehyde and an aldehyde trapping compound; and powdered or granular aldehydes A step of dripping or spraying the envelope in the molten state into the collection compound; cooling and solidifying the envelope; and collecting powder or particles of the aldehyde collection compound or a plurality of aldehydes And at least a part of the outer surface of a lump made of powder or granules of the compound for use, and the step of obtaining a composite for collecting aldehydes coated with the outer covering. A step of containing the aldehydes collecting agent according to any one of claims 1 to 6 in a formaldehyde-based adhesive, and a formaldehyde-based adhesive containing a compound for collecting aldehydes obtained in the step described above on a wooden board A method for producing a wood board comprising at least a step of adding to the wood material, and a step of heat-pressing the wood material to which the adhesive obtained in the step is added to obtain a wood board by bonding the wood material. A step of adding a formaldehyde-based adhesive to the wood material, a step of dispersing and containing the aldehyde-based scavenger described in any one of claims 1 to 6 in the wood material, and the two steps ( However, the order of steps does not matter) A method for producing a wood board comprising at least a step of obtaining a wood board by adhering the wood material by heat-pressing the wood material to which the obtained adhesive is added. A wooden board obtained by hot pressing the wooden material after adding the aldehyde-collecting agent according to any one of claims 1 to 6 to the wooden material.