JPH0482704A - Production of modified wood - Google Patents

Abstract

PURPOSE:To cause a wood to be dimensionally stable throughout, have excellent flame retardancy, be insusceptible to deterioration in strength and retain a wood feeling on the surface thereof, by impregnating a raw material wood with a specified compound and a polymerization initiator, and causing formation and fixation of an insoluble hardened resin in the texture of the wood at a temperature in a specified range. CONSTITUTION:One compound selected from an acrylamide, a guanidine and urea, one compound selected from the group consisting of phosphoric acid, phosphorus compounds, boric acid, borates and halides, and a polymerization initiator are infiltrat ed into a raw material wood in the state of being dissolved in water. The wood thus impregnated is then heated by one of the following three methods (1) to (3), whereby an insoluble hardened resin is formed and fixed in the texture of the wood. (1) Once heating in a comparatively low temperature range of 60-90 deg.C, and then heating in a high temperature range of 100-150 deg.C. (2) Heating only in the comparatively low temperature range of about 60-90 deg.C. (3) Heating only in the high temperature range of about 100-150 deg.C. The polymerization initiator may be, for example, a radical polymer ization initiator such as hydrogen peroxide, potassium persulfate and ammonium persulfate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing modified wood used for housing equipment, building materials, etc.

[Conventional technology]

Conventionally, methods for imparting dimensional stability to wood include, for example, the following methods (1) to (2).

■ After impregnating the wood with acetic anhydride and a catalyst such as potassium acetate, by heating it at 100 to 130°C,
A method of replacing the hydroxyl groups of wood cellulose with acetyl groups (acetylation). According to this method, the hydrophilic hydroxyl groups of wood cellulose are replaced with hydrophobic acetyl groups, so
As a result of the reduced hygroscopic (water) property of the wood, dimensional changes in the wood are reduced.

(2) A method in which resin is produced in wood by impregnating it with styrene, methyl methacrylate, etc., and then heating or irradiating it with electron beams (WPC manufacturing method). According to this method, in addition to improving dimensional stability, hardness and wear resistance are also improved.

■ A method of imparting high dimensional stability by impregnating wood with a resin having an isocyanate group or an epoxy group and reacting the resin with the wood [Problem to be solved by the invention] However, methods of The methods are as follows (7)
-ke) had the following problems.

(G) In the method (2) above, it is difficult to completely acetylate the cellulose inside the wood, so it is not possible to stabilize the dimensions of the inside of the wood. In addition, a sufficient acetylation rate is not obtained and unreacted acetic acid remains in the wood, resulting in an acetic acid odor and the acetic acid destroying the wood structure and reducing the strength of the wood.

(a) In the method (2) above, since the monomer impregnated into the wood is hydrophobic, the same monomer is not impregnated into the cell walls of the wood. Therefore, in order to impart high dimensional stability, it is necessary to impregnate the wood with as much as 50 to 100% by weight of the amount of wood M before impregnation. the result,
The wood texture of the wood surface disappears.

(1) In method (2) above, there is a possibility that the resin that is impregnated into the wood and reacted with the wood components will harden, and if the resin hardens, the degree of curing shrinkage will be large and the wood structure will be destroyed. As a result, the wood swells more than untreated wood, reducing dimensional stability and reducing the strength of the wood.

Further, in the methods (1) to (4) above, there was a problem in that although dimensional stability could be imparted to wood, flame retardancy could not be imparted at the same time.

In view of these circumstances, this invention achieves dimensional stability even inside the wood, has little residual unreacted chemicals, has a small degree of strength deterioration, does not lose its surface wood texture, and is flame retardant. An object of the present invention is to provide a method that can efficiently obtain modified wood having the following properties.

[Means to solve the problem]

In order to solve the above problems, the method for producing modified wood according to the present invention comprises: acrylamides, at least one of guanidines and urea; and phosphoric acid, phosphorus compounds, boric acid, borates, and halogen compounds. After impregnating raw material wood with at least one selected from the group consisting of a polymerization initiator and a polymerization initiator dissolved in water,
1 selected from the following (al, (b) and fc)
By performing the seeding method, an insoluble cured resin is generated and fixed within the wood structure.

(a) Once heated within a relatively low temperature range of about 160 to 90°C, it is heated within a high temperature range of about 100 to 150'C.

(b Heating only within a relatively low temperature range of about 160 to 90°C.

(Heat only within a high temperature range of about 1100 to 150°C.

The raw material wood to be modified in the present invention is not particularly limited, and includes, for example, raw wood logs, sawn timber products, sliced veneers, rotary veneers, plywood, and the like. There are no limitations on the tree species, etc.

The acrylamide used in this invention is not particularly limited, but includes, for example, acrylamide, methylol acrylamide, dimethylol acrylamide, methacrylamide, methylol methacrylamide, dimethylol methacrylamide, and the like. These are 1
Seeds alone or a mixture of multiple types can be used.

Since these acrylamides have hydrophilic groups such as amide groups and methylol groups, they are soluble in water, and by impregnating them in a dissolved state in water, it is possible to impregnate the inside of wood cell walls. Acrylamides also have vinyl groups and can be easily polymerized by heating, etc., so acrylamides are polymerized by impregnating them into wood and then heating the wood to cause a polymerization reaction.
By forming acrylamide+1tll in wood, high dimensional stability can be imparted to the inside of the wood. However, when the acrylamide resin is polymerized by low-temperature heating, it may be water-soluble, so there is a risk that it will seep out of the wood due to water or moisture, reducing the dimensional stability of the wood. be. Therefore, as will be explained in detail later, the acrylamide resin is heated at a relatively low temperature and/or high temperature to crosslink (cure) the acrylamide resin, thereby ensuring that it becomes insoluble in water. The crosslinking reaction of acrylamide resin occurs between and within the molecules of the resin via functional groups such as vinyl groups and amide groups in the resin.

In particular, when the acrylamide resin has a methylol group, the methylol groups within and between molecules of the resin are also crosslinked by condensation, resulting in an insoluble cured resin with a higher degree of crosslinking. If the acrylamide resin produced within the wood becomes insoluble in water, there is no risk that the resin will seep out of the wood due to water or moisture, and it will be fixed within the wood, resulting in modified wood with high dimensional stability. It also improves the water and moisture resistance of the same wood. In addition, as will be explained in detail later, the acrylamide resin undergoes a condensation reaction (crosslinking reaction) with hydrophilic hydroxyl groups in cellulose, which is a wood component, by heating at high temperatures.
It is possible to make the hydroxyl group hydrophobic by doing so. If the hydroxyl group becomes hydrophobic, the water absorption and moisture absorption of the wood will decrease, further improving the dimensional stability of the wood. However, in order to impart flame retardancy to wood, acrylamide alone is insufficient. Therefore, in this invention, in addition to acrylamides, it is necessary to impregnate the wood with an effective flame retardant agent dissolved in water. As the flame retardant agent, at least one of guanidines and urea, and at least one selected from the group consisting of phosphoric acid, phosphorus compounds, boric acid, borates, and halogen compounds are used.

Examples of guanidines include, but are not limited to, guanidine, melamine, methylolmelamine, guanomelamine, dicyandiamide, guanylurea (dicyancyamidine), and the like. These are only one type,
Alternatively, a mixture of multiple types can be used. Also, these are
If necessary, it can also be used in combination with urea. Alternatively, urea may be used instead of these guanidines. Since these guanidines and urea are water-soluble like the acrylamides, they can be impregnated into the cell walls of wood in a state in which they are dissolved in water. After impregnation, it is easily copolymerized and cured with the acrylamide by heating and becomes insoluble in water, so that an insoluble cured resin having dimensional stabilization and flame retardant effects is generated and fixed in the wood.

In addition, phosphoric acid, phosphorus compounds, boric acid, borates, halogen compounds, etc. contain elements that have a flame retardant effect such as P, B, C1, B (hereinafter these are referred to as "flame retardant elements"). By impregnating the raw material wood with at least one of these substances, the flame retardance of the wood is further improved.

These flame retardant element-containing substances are water-soluble, and by impregnating them in a dissolved state in water, they can be easily impregnated into the cell walls of wood. After impregnation, when the acryl amylose, guanidine and/or urea are polymerized and crosslinked by heating, etc., they react with the flame retardant element-containing substance, resulting in an insoluble hardened product. Since the flame retardant element-containing substance is incorporated into the resin and fixed in the wood together with the insoluble cured resin, there is no risk that the flame retardant element-containing substance will be leached out of the wood. If the chemical element containing substance is an acid,
It also has the effect of acting as an acid catalyst for the polymerization/crosslinking reaction of the acrylamides and guanidines and/or urea.

However, if the flame retardant element-containing substance is an acid, it is possible that the same number will destroy the wood structure and reduce the strength of the wood. Since it is fixed and does not come loose after that, deterioration in the strength of the wood is suppressed.

Examples of phosphoric acid include, but are not limited to, orthophosphoric acid and the like. Examples of the phosphorus compound include, but are not limited to, ammonium hydrogen phosphate, sodium hydrogen phosphate, and the like. Examples of boric acid include, but are not limited to, orthoboric acid and the like. Examples of the borate include, but are not limited to, sodium borate and the like.

Examples of the halogen compound include, but are not limited to, halogenated acids such as hydrochloric acid and hydrochloric acid.In the present invention, the acrylamide, guanidine, and/or urea are efficiently polymerized and cured within the wood. In order to achieve this, it is necessary to impregnate raw material wood with a polymerization initiator dissolved in water.

The polymerization initiator is not particularly limited as long as it is water-soluble, and examples thereof include radical polymerization initiators such as hydrogen peroxide, potassium persulfate, and ammonium persulfate. These radical polymerization initiators can also be used as a redox catalyst initiator in combination with a reducing agent. These polymerization initiators may be used alone or in combination.

Moreover, when the flame retardant element-containing substance is a neutral salt, an acid catalyst may also be impregnated into the wood, if necessary. For example, when the acrylamide has a methylol group such as methylolacrylamide, it is impregnated for the purpose of promoting the condensation of the methylol group as described above. Such acid catalysts are not particularly limited as long as they are water-soluble; for example,
Preferred are materials that are approximately neutral at room temperature but become acidic by dissociating the acid when heated, such as ammonium chloride. When used, the acid catalyst may be used alone or in combination.

Acrylamides, guanidines and/or urea, a flame retardant element-containing substance, and a polymerization initiator (hereinafter collectively referred to as "impregnated components") are dissolved in water (hereinafter referred to as "impregnated components"). There are no particular limitations on the method of impregnating the raw material wood with the treatment liquid (referred to as "treatment liquid"), but for example,
Examples include a reduced pressure impregnation method, a pressurized impregnation method, a normal pressure immersion method, and a coating method. Before impregnating with the impregnating treatment liquid, it is recommended that the roughening material wood be subjected to a water saturation treatment. This is because the impregnating components contained in the impregnating solution are quickly impregnated (diffused) into the wood using the water in the wood as a medium, so the impregnation time can be shortened. The method of water saturation treatment is not particularly limited, but may be carried out by submerged wood storage, steaming, reduced pressure impregnation, pressurized impregnation, or the like. Note that when impregnating with the impregnating treatment liquid under reduced pressure, it is not necessarily necessary to perform this water saturation treatment.

In addition, in order to improve processing efficiency, impregnation treatment with impregnating components is usually carried out by including all the necessary impregnation components in one impregnation treatment solution and impregnating the wood with the same impregnation treatment solution. However, it is not limited to this. For example, each impregnating component may be separately impregnated with a plurality of types of impregnating treatment liquids. That is, the impregnation timing of each impregnating component is not limited at all as long as it is before the heat treatment described below.

The method for preparing the impregnation treatment solution is not particularly limited, but
For example, when impregnating all the components that need to be impregnated in one impregnating solution, guanidines and/or urea are added to a 10 to 50% aqueous solution of acrylamide at a concentration of 10 to 30% by weight relative to the aqueous solution. % by weight, and further add appropriate amounts of flame retardant element-containing material and polymerization initiator and mix.

As described above, the following fa), fb) and fc
) by performing one method selected from
Generates and fixes an insoluble hardened resin within the wood structure.

fa) Once heated within a relatively low temperature range of about 60 to 90°C, then heated within a high temperature range of about 100 to 150°C.

(b) Heating only within a relatively low temperature range of about 60-90°C.

(c) Heating only within a high temperature range of about 100-150°C.

The heating method is not particularly limited, but includes, for example, a method of drying the impregnated wood with hot air, a method of heating with high frequency waves or an electron beam, and the like.

Polymerization and curing (crosslinking) of acrylamides, guanidines, and/or urea can be proceeded by heating at a relatively low temperature of about 60 to 90°C. It is particularly preferable to heat at a temperature of about 60 to 70°C.

This is because polymerization and curing at such temperatures will further reduce the degree of curing shrinkage of the resin and increase the bulking effect, thereby further improving the dimensional stability of the wood.

Furthermore, in order to further improve the dimensional stability of wood, as described above, it is effective to cause the hydrophilic hydroxyl groups of wood cellulose to undergo a crosslinking reaction with acrylamides to make the hydroxyl groups hydrophobic. The hydrophobization reaction of the hydroxyl group is performed at 10
By heating at a high temperature of about 0 to 150℃,
It can be carried out efficiently. Of course, by heating at such a temperature, polymerization and curing of the acrylamide, guanidine, and/or urea also proceeds.

Since the hydrophobization reaction is a condensation reaction, if a large amount of water is present in the wood, the reaction rate tends to be slow due to chemical equilibrium. Therefore, in order to allow the hydrophobization reaction to proceed as efficiently as possible, it is desirable to remove as much moisture from the wood as possible in advance. In order to carry out such a process, although not particularly limited, the wood after impregnation treatment is first treated with a 60%
After heating at a relatively low temperature of ~90°C to advance the polymerization/curing reaction of acrylamides, guanidines and/or urea, and lowering the moisture content of the wood, heating at a relatively low temperature of around 100~150°C It is desirable to heat the wood at a temperature to promote cross-linking reactions between the resin and the wood cellulose. In this way,
By sequentially heating within two temperature ranges (performing method (a) above), the bulking effect and the hydrophobizing effect of the hydroxyl groups of wood cellulose as described above can be obtained.
It becomes possible to obtain higher dimensional stability.

Note that the heat treatment of the wood after the impregnation treatment may be performed by sequentially heating within two temperature ranges as in the method (al) above, or in one heat treatment as in the methods (b) and (c) above. Heating may be performed only within one temperature range.The heating time within each temperature range is not particularly limited.

In the above manner, insoluble hardened resin is generated within the wood.
After fixing, the surface of the wood is washed with water, if necessary, and dried to obtain the desired modified wood.

[For production]

After impregnating raw wood with a component that produces an insoluble cured resin that has a dimensional stabilizing effect and a flame retardant effect dissolved in water, the aqueous solution is caused to react within the wood. Since the resin has good permeability to the wood, the component is impregnated into the wood tissue and then changes into the insoluble cured resin. As a result, the interior of the wood is highly dimensionally stabilized and flame retardant. Since the components react at a high reaction rate, the amount of unreacted drug remaining is reduced. Since the above-mentioned components have a small degree of curing shrinkage, the degree of destruction of the wood structure is reduced, so that deterioration in the strength of the wood is suppressed. As mentioned above, the above ingredients are efficiently impregnated into the inside of the wood, so the amount of impregnation required for dimensional stabilization is small.Furthermore, after impregnation, the ingredients become insoluble in water and are fixed inside the wood, leaving them on the wood surface. Since there is no risk of it seeping out, the wood texture of the wood surface is maintained.

〔Example〕

Hereinafter, specific examples of the present invention will be described in detail together with comparative examples, but the present invention is not limited to the following examples.

Example 1 - Water: methylol acrylamide (hereinafter referred to as rMAM)
(abbreviated as J): methylolmelamine (hereinafter referred to as rMM)
0.5% by weight of potassium persulfate based on MAM was added as a radical polymerization initiator to an aqueous solution prepared by mixing diphosphoric acid at a ratio of 3:1:1:1 (weight ratio). Mixed. This aqueous solution was applied to 5 pieces of agathis veneer with a width and length of 220fi and a thickness of 3.
After impregnation (0 mHg), it was impregnated for -8 minutes by the normal pressure immersion method.

Thereafter, the veneer was heated at 70° C. for 6 hours and then at 150° C. for 2 hours to obtain a modified wood veneer in which an insoluble cured resin was generated and fixed inside.

The impregnation rate expressed by the following formula +11 was investigated for the obtained modified wood veneer, and the results are shown in Table 1. The dimensional stability was evaluated by the anti-hygroscopic ability expressed by the following formula (2) and the anti-water absorption ability expressed by the following formula (3), and the results are shown in Table 1.

) I (In formula (2), S represents the hygroscopic swelling rate of untreated wood,
S! represents the hygroscopic swelling rate of treated wood. ) Next, a set of five modified wood veneers was laminated and bonded to form a plywood, and its flame retardance was examined. The flame retardancy is JIS A for the plywood.
A surface heating test based on 1321 was conducted, and the evaluation was rated O if the flame retardant grade 3 was passed, and the evaluation was rated × if it failed. The results are shown in Table 1.

In addition, a test piece of the end surface of agathis wood with a width and length of 40 fl and a thickness of 5 mm was subjected to the same treatment as the veneer described above to obtain a test piece of the end surface of the modified wood. , the dimensional stability of the modified wood was determined (in formula (3), T1 represents the water absorption swelling ratio of untreated wood, and Tt represents the water absorption swelling ratio of treated wood). Example 2 - Water: MAM: MM diphosphoric acid = 3:1:1:1
0.5% by weight of potassium persulfate based on MAM was added as a radical polymerization initiator to the aqueous solution prepared by mixing at a ratio of (weight ratio). This aqueous solution was impregnated under reduced pressure (50 wml (g)) on 5 Agatis veneers each having a width and length of 220 fl and a thickness of 3 W. After that, the solution was impregnated for -8 minutes using the normal pressure immersion method. 2.Plate at 70℃
By heating for 4 hours, a modified wood veneer in which an insoluble cured resin was generated and fixed was obtained.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was examined in the same manner as in Example 1. The results are shown in Table 1.

In addition, a test piece of the end surface of agathis wood having a width and length of 40 mm and a thickness of 5 mm was treated in the same manner as the veneer described above to obtain a test piece of the modified wood end surface. Thereafter, the dimensional stability of the modified wood was examined in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 - 0.5% by weight of MAM as a radical polymerization initiator was added to an aqueous solution prepared by mixing water:MAM:MM diphosphoric acid at a ratio of 3:1:1:I (weight ratio). of potassium persulfate was added and mixed. This aqueous solution was impregnated under reduced pressure (50 mHg) on five Agatis veneers with a width and length of 220 m and a thickness of 3 m, and then impregnated under pressure of 10 kg/- for 1 hour. -8 by pressure immersion method
Impregnated for a while.

Thereafter, the veneer was heated at 70° C. for 24 hours to obtain a modified wood veneer in which an insoluble cured resin was generated and fixed.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was examined in the same manner as in Example 1. The results are shown in Table 1.

In addition, a test piece of the end surface of agathis wood with a width and length of 40 millimeters and a thickness of 5B was treated in the same manner as the veneer described above to obtain a test piece of the modified wood end surface. The dimensional stability of the modified wood was examined in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 Water: MAM: MM dilinic acid-5:1:1:1
0.5% by weight of potassium persulfate based on MAM was added as a radical polymerization initiator to the aqueous solution prepared by mixing at a ratio of (weight ratio). This aqueous solution was impregnated under reduced pressure (50 mHg) on five agathis veneers with a width and length of 220 mm and a thickness of 3 WM.Then, the veneers were impregnated for one day using the normal pressure immersion method. By heating at 70°C for 6 hours and then at 150°C for 2 hours,
A modified wood veneer in which insoluble cured resin was generated and fixed was obtained.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was examined in the same manner as in Example 1. The results are shown in Table 1.

In addition, a test piece of the end surface of agathis wood having a width and length of 40 mm and a thickness of 5 mm was treated in the same manner as the veneer described above to obtain a test piece of the modified wood end surface. Thereafter, the dimensional stability of the modified wood was examined in the same manner as in Example 1, and the results are shown in Table 1.

Example 5 - 0.5% by weight of MAM as a radical polymerization initiator was added to an aqueous solution prepared by mixing water:MAM:MM diphosphoric acid at a ratio of 5:2:1:1 (weight ratio). of potassium persulfate was added and mixed. This aqueous solution was impregnated with reduced pressure (50+nHg) on five Agatis veneers with a width and length of 220W and a thickness of 3fi, and then soaked for one day using the normal pressure immersion method. By heating at 70° C. for 6 hours and then at 150° C. for 2 hours, a modified wood veneer in which an insoluble cured resin was generated and fixed was obtained.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was reduced in the same manner as in Example 1, and the results are shown in Table 1. .

In addition, after applying the same treatment as the above veneer to a test piece of the end surface of agathis wood having a width and length of 40 m and a thickness of 5 m to obtain a test piece of the end surface of modified wood, The dimensional stability of the modified wood was examined in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 - MA was added as a radical polymerization initiator to an aqueous solution prepared by mixing water:MAM at a ratio of 3:1 (weight ratio).
Potassium persulfate (0.5% by weight based on MAM) and ammonium chloride (3% by weight based on MAM) as an acid catalyst were added and mixed. The width and length of this aqueous solution are 2
At 20fi, reduce pressure (
After impregnating 50 ml (g), it was impregnated for one day by the normal pressure immersion method.

Thereafter, the veneer was heated at 70° C. for 6 hours and then at 150° C. for 2 hours to obtain a modified wood veneer in which an insoluble cured resin was generated and fixed inside.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in the example work, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and this plywood was tested for flame retardancy in the same manner as in Example 1, and the results are shown in Table 1. .

In addition, after applying the same treatment as the above veneer to a test piece of the end surface of agathis wood having a width and length of 40 m and a thickness of 5 m to obtain a test piece of the end surface of modified wood, The dimensional stability of the modified wood was examined in the same manner as in Example 1, and the results are shown in Table 1.

- Comparative Example 2 - To an aqueous solution prepared by mixing water: MM diphosphoric acid in a ratio of 3:1:1 (weight ratio), 0.5% by weight of potassium persulfate based on MM was added as a radical polymerization initiator. was added and mixed. This aqueous solution has a width and length of 220 mm.
1, apply vacuum (50W) to 5 Agatis veneers with a thickness of 3 fl.
mHg) and then impregnated for -8 hours by normal pressure immersion method.

Thereafter, the veneer was heated at 70° C. for 6 hours and then at 150° C. for 2 hours to obtain a modified wood veneer in which an insoluble cured resin was generated and fixed inside.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was examined in the same manner as in Example 1. The results are shown in Table 1.

In addition, a test piece of the end surface of Agatis wood with a width and length of 40 mm and a thickness of 5 fi was subjected to the same treatment as the veneer described above to obtain a test piece of the modified wood end surface. The dimensional stability of the modified wood was examined in the same manner as in Example 1,
The results are shown in Table 1.

Comparative Example 3 - MAM was added as a radical polymerization initiator to an aqueous solution prepared by mixing water:MAM at a ratio of 3:1 (weight ratio).
Potassium persulfate (0.5% by weight based on MAM) and ammonium chloride (3% by weight based on MAM) as an acid catalyst were added and mixed. The width and length of this aqueous solution are 2
201, reduce pressure (50
mHg) and then impregnated for -8 hours by normal pressure immersion method.

Thereafter, the veneer was heated at 70° C. for 24 hours to obtain a modified wood veneer in which an insoluble cured resin was generated and fixed.

The impregnation rate of the obtained modified wood veneer was examined in the same manner as in Example 1, and the results are shown in Table 1.

Next, a set of five modified wood veneers was laminated and bonded to produce plywood, and the flame retardance of this plywood was examined in the same manner as in Example 1. The results are shown in Table 1.

In addition, a butt side test piece of agathis wood with a width and length of 40 m and a thickness of 5 NM was treated in the same manner as the veneer described above to obtain a butt side test piece of modified wood. The dimensional stability of the modified wood was examined in the same manner as in Example 1,
The results are shown in Table 1.

Table 1 As shown in Table 1, the modified wood obtained in Examples 1 to 5 has both dimensional stability and flame retardancy compared to the modified wood obtained in Comparative Examples 1 to 3. It can be seen that both are excellent.

〔Effect of the invention〕

According to the method for producing modified wood according to the present invention, the inside of the wood is highly dimensionally stabilized, has excellent flame retardancy, has little residual odor from unreacted chemicals, has a small degree of deterioration in strength, and has Modified wood without loss of texture can be efficiently obtained.

In addition, since the active ingredients generated inside the modified wood are insoluble in water, there is no risk of them seeping out onto the wood surface due to water or moisture, so the modified wood has good water resistance and moisture resistance. Are better.

Agent: Patent Attorney Takehiko Matsumoto Procedural Amendment (view), Case Indication and Review No. 2-200737 No. 2, Title of Invention: Process for Manufacturing Modified Wood 3, ?!Relationship with the Correcting Person Case Patent Applicant Residence Address: 1048 Oaza Kadoma, Kadoma City, Osaka Name (583) Matsushita Electric Works Co., Ltd. 4 Agent address: 1-2 Hannan-cho, Abeno-ku, Osaka City, Osaka Prefecture 545
5-6 Phone number (06) 622-8218 5. Name (7346) Patent attorney Takehiko Matsumoto, number of terms to be included in the amendment
5-No one 6,? ! Positive subject specification 7, contents of amendment ■ Page 3 of the specification, lines 9 to 12, it says “(H) Unreacted acetic acid that could not be obtained by the method of ■” rC7)
In the method (2) above, the by-product is acetic acid.''

■ On page 4, lines 4 to 5 of the Meiji M, the phrase ``if the reacted resin cures, its curing shrinkage'' is corrected to read ``the curing shrinkage of the reacted resin itself.''

■ On page 4, lines 12-13 of the specification, the statement ``This invention has little residual odor of chemicals even inside the wood'' has been changed to ``This invention has highly dimensional stability and has little odor.'' correct.

■ Lines 5 to 4 from the bottom of page 6 of the specification states, "By forming an acrylamide resin, high dimensional stability is achieved even inside the wood.""Sex," he corrected.

■ On page 7, lines 6 to 11 of the specification, it is stated that "[The crosslinking reaction is caused by crosslinking in the same resin, resulting in a higher degree of crosslinking"]. In particular, when the acrylamide resin has methylol groups, the degree of crosslinking is higher because the crosslinking reaction also occurs when the methylol groups undergo a condensation reaction.

■ Lines 5 to 3 from the bottom of page 17 of the specification states, ``As a result, the inside of the wood is highly graded...with little residual odor of chemicals.''
The wood becomes highly dimensionally stable and flame retardant. The above components transform into a resin with a high reaction rate and low odor, so
"Modified wood has less odor," he corrected.

■ On page 31, lines 6 to 8 of the specification, the phrase "modified wood according to this invention...has little residual odor of chemicals" has been replaced with "according to the manufacturing method of modified wood according to this invention, highly dimensional It is stabilized, has excellent flame retardant properties, and has little odor.''

Claims (1)

[Claims] 1. Acrylamides, at least one of guanidines and urea, phosphoric acid, phosphorus compounds, boric acid,
After impregnating raw material wood with at least one selected from the group consisting of borates and halogen compounds and a polymerization initiator in a state dissolved in water, the following (a) is applied to the raw material wood. , (b) and (c) to produce and fix an insoluble cured resin within the wood structure. (a) Once heated within a relatively low temperature range of about 60 to 90°C, then heated within a high temperature range of about 100 to 150°C. (b) Heating only within a relatively low temperature range of about 60-90°C. (c) Heating only within a high temperature range of about 100-150°C.