JPS61171744A - Wood-based foamed material and production thereof - Google Patents

Abstract

PURPOSE:To produce a novel foam composed of solubilized wood raw material, by dissolving a chemically modified wood in a specific organic solvent, adding a crosslinking agent or a curing agent and optionally, a foaming agent to the solution, and foaming and curing the mixture. CONSTITUTION:The objective foam can be produced by (1) dissolving (A) 10-95(wt)%, preferably 50-90% chemically modified wood obtained by introduc ing substituent groups to a part of the hydroxyl groups of cellulose, hemicellulose or lignin in wood, e.g. methylated wood flour in (B) an organic solvent having polymerizable active group, preferably a polyhydric alcohol or phenol, in the presence of hydrochloric acid, etc., preferably at 80 deg.C, (2) if necessary, neutralizing the wood solution, (3) adding a crosslinking agent or a curing agent active to polymerize the active group of A and B, and if necessary, adding a foaming agent during or before the polymerization, and (4) foaming and curing the mixture under heating or at normal temperature.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a wood-based foam and a method for producing the same.

PRIOR ART Foamed materials (synthetic wood) made by mixing wood flour as a wood material with foamable resin have been well known, but in this case, the wood flour is simply used as a filler or aggregate. However, since the wood flour and the foam resin are not compatible with each other, the characteristics of the wood-based raw material are not effectively utilized. The main reason why such compatibilized wood-based foams have not been obtained so far is that wood containing various components is difficult to dissolve in various solvents.

By the way, as part of the utilization of wood-based raw materials including wood, wood that has been chemically modified by introducing at least one type of organic substituent into some of the hydroxyl groups (chemically modified wood) has been used in organic solvents. It has been proposed that the resulting wood solution be used as a raw material for various resins (see JP-A No. 57-2360). Also, Tokukai Showa No. 5
No. 9-174814 discloses a method for producing plasticized wood filaments from a wood solution. Like this,
Examples of turning wood into resin can be found here and there in the literature, but there are no known examples of turning wood into foam.

Purpose of the Invention In view of the above circumstances, the inventors of the present invention aimed to obtain a new foam in which wood-based raw materials are compatibilized, and as a result of various studies, the inventors of the present invention have developed an organic material that uses chemically modified wood. The present invention was completed based on the discovery that a wood foam having excellent properties can be obtained by preparing a wood solution by dissolving it in a solvent, foaming and curing this solution.

Components of the Invention Namely, the present invention is directed to a reaction obtained by dissolving chemically modified wood in an amount of 10 to 95% by weight, preferably 50 to 90% by weight, in an organic solvent having an active group capable of polymerization. A solvent and a crosslinking agent or curing agent that polymerizes the active groups in the chemically modified wood are added to the water solution, and the resin is made into a resin by heating or at room temperature. The object of the present invention is to provide a method for producing a foam by adding a foam, foaming, and simultaneously converting it into a resin.

The present invention also provides a novel wood-based foam obtained as described above.

The chemically modified wood according to the present invention is prepared by a well-known method using pulverized wood such as wood flour, wood fiber, wood chips, and veneer waste, and plant cellulose such as straw and rice husk as raw materials. be able to.

The reaction for chemically modifying a wood material by introducing a substituent into it is a reaction in which a substituent is introduced into at least a portion of each hydroxyl group of cellulose, hemicellulose, or lignin present in the wood material, such as This includes esterification or etherification reactions of hydroxyl groups.

Various acids such as acid halides, acid anhydrides, dibasic acid anhydrides, and fatty acids are used for esterification, and halogens such as methyl chloride, ethyl chloride, allyl chloride, benzyl chloride, and ethylene chlorohydrin are used for etherification. α-halogen acids such as sodium monochloroacetate and monochloroacetic acid; dialkyl sulfates such as dimethyl sulfate and diethyl sulfate;
Epoxy compounds such as ethylene oxide and propylene oxide; vinyl compounds activated with negative groups such as acrylonitrile; diazomethane: formaldehyde
Aldehydes such as q:□; organometallic compounds such as titanium alkylate, etc. are used. Further, these reactions may be carried out without a catalyst or under a catalyst, and in the former case, a catalyst such as sulfuric acid, pyridine perchlorate, or zinc chloride can be used, and in the latter case, an alkaline catalyst such as caustic soda can be used.

Suitable examples of organic groups to be introduced include fatty acid acyl groups such as acetyl, propionyl, butyryl, and valeroyl groups; dibasic acid monoester groups such as carboxypropenoyl; benzoyl and other aromatic acyl groups; methyl group, lower alkyl groups such as ethyl group; allyl group; carboxymethyl group: hydroxyalkyl group such as hydroxyethyl group, polyoxyalkylene glycol group such as polyoxymethylene group, polyoxyethylene glycol group; benzyl group; pentyl group, Examples include long-chain alkyl groups such as octyl groups; cyanoethyl groups; methylene ether groups; and analogous groups. Furthermore, it is also possible to introduce two or more of these organic groups, for example, an acetyl group and a butyryl group.

In addition to organic groups, inorganic groups, such as nitro groups, and organic groups containing atoms other than carbon, hydrogen, oxygen, and nitrogen, such as organometallic groups, may be introduced.

The number of substituents to be introduced is not necessarily limited to one type.

This chemical modification treatment of wood is usually carried out by treating fibrous or powdered wood with a corresponding compound in the presence of a solvent or a swelling agent at room temperature or under heated conditions.

The treated wood is thoroughly washed, for example, by putting it in water or methanol, collecting it, washing it with water or methanol, and then drying it if necessary. Alternatively, after washing with methanol, drain the liquid and add polyhydric alcohol, or after washing with methanol, wash with polyhydric alcohol, and mix again with the required amount of polyhydric alcohol to directly form a solution. .

According to the research of the present inventors, chemically modified wood obtained by such a reaction can be more or less treated with water, various aqueous solutions, organic solvents, or any of these, depending on the type and degree of substituent introduced. The solubility and affinity for mixed solvents have been improved.

Among the various methods listed above, the chemical modifications of wood suitable for use in solution include acetylation, monoesterification with maleic or phthalic acid, ethylation, methylation, carboxymethylation, hydroquinone. These include ethylation and allylation. In the case of etherification, the weight increase rate is also relatively low, with only one-third of the hydroxyl groups in the wood being etherified.

The type of chemically modified wood that can be used in the present invention is not particularly limited, but among the above, those with active groups such as carboxymethylation, hydroxyethylation, and carboxypropenoylation are preferable, and those with inert groups introduced are preferable. If so, use chemically modified wood rich in unreacted hydroxyl groups. Also,
The weight increase rate is preferably 50% or less. These chemically modified woods are then dissolved in various organic solvents.

The solvent must have an active group that can be polymerized, such as polyhydric alcohols, phenols,
Includes vinyl monomers, glycidyl compounds, etc. In order to form a solution at a high concentration, it is necessary to solvolyze the vinyl monomer and glycidyl compound.
halogen groups) are not preferred. Therefore, polyhydric alcohols and phenols are preferred in the method of the invention. Further, the dissolution may be a dope-like solution in which the wood is not partially dissolved.

The polyhydric alcohols used in the present invention include ethylene glycol, propylene glycol as dihydric alcohols,
trimethylene glycol, l,4-butanediol, 1
．． 5-bentanediol, 1,6-hexanediol,
l, 2-hexanediol, 2.4-hexanediol, 1.7-hebutanediol, 1.8-octanediol, 1.9-nonanediol, ■, 10-decanediol, pinacol, cyclopentane 1.2 -diol, cyclohexane-1,2-diol, cyclohexane 1,
4-diol, bisphenol A1 polio
These include t-xypropylene glycol, polyoxypropylene-polyoxyethylene glycol, and the like. Further, examples of the trihydric alcohol include glycerin. Alternatively, it may be a mixture of these polyhydric alcohols, a monohydric lower alcohol such as methanol, or a mixture of a polyhydric alcohol and a suitable solvent mainly having a low boiling point such as acetone. These low boiling point solvents can be removed after solution formation.

Further, the phenols used in the present invention include phenol, resorcinol, and cresol.

Acids that can be used as catalysts for solvolysis include hydrochloric acid,
Mention may be made of mineral acids such as sulfuric acid and trifluoroacetic acid, and Lewis acids such as aluminum chloride, zinc chloride, boron trifluoride and the like.

Dissolution with solvolysis is carried out at temperatures from room temperature to the boiling point of the solvent. Preferably about 60-100°C, especially 8
A temperature around 0°C is appropriate. Under these conditions, dissolution is achieved in 15 minutes to several hours. The wood concentration in the wood solution thus obtained ranges from a few % to 95% by weight, depending on the amount of chemically modified wood used. This solvolysis °
It is applicable to many types of chemically modified wood, such as methylated wood, ethylated wood, allylated wood, carboxymethylated wood, hydroxyethylated wood, acetylated wood, etc. For example, when dissolving these woods in polyhydric alcohol at around 80°C to achieve the above concentration range, 0.5
to 20% by weight (preferably 3 to 20%) of hydrochloric acid. In this case, the solvolysis is completed within minutes to hours and a complete solution is obtained.

As a dissolving device, a reactor is capable of sufficient stirring during dissolution and can also apply torque during the stirring.
For example, Nigu can be used to facilitate dissolution and ease the solvolysis dissolution conditions. Furthermore, it is also possible to add and coexist an organic solvent such as water or acetone from the beginning or during the dissolution process to achieve more uniform mixing and dissolution.

The quantitative relationship between chemically modified wood and solvents used in solvolysis is 100 parts of chemically modified wood IO per 100 parts of solvent.

When the obtained wood solution is an acidic solution, it is unstable as it is, and in some cases, lignin and the like may condense and precipitate. Therefore, depending on the case, the acid may be neutralized or the double salt may be precipitated and removed. As the neutralizing agent, inorganic bases such as sodium hydroxide and organic bases such as triethylamine can be used.

The wood solution thus obtained is foamed in the presence of a crosslinking agent or hardening agent and a foaming agent, if necessary.

Of course, the crosslinking agent or curing agent must be selected depending on the type of solution. For example, in a polyhydric alcohol solution, polyvalent isocyanate compounds, polyvalent glycidyl compounds, melamine derivatives, etc. can be used. In some cases, after the entire solution is converted into a polyglycidyl ether by reacting with epichlorohydrin, amines, polyvalent isocyanates, and acid anhydrides may be used as crosslinking agents. On the other hand, in the case of a phenol solution, formaldehyde may be added to form methylol. Further, in addition to the above-mentioned crosslinking agents or curing agents, a catalyst for promoting the reaction may be added as necessary. In particular, for polyglycyl compounds, amines,
Acid anhydrides and isocyanates are effective, and in the case of phenol solutions, acids or alkalis are effective.

Further, as blowing agents, there are those that are gasified by thermal decomposition such as ammonium carbonate, sodium bicarbonate, and azodicarbonamide, and low fluorocarbon solvents such as Freon. Note that there are also isocyanate-based materials that generate gaseous bodies in the presence of water.

Examples of polyvalent isocyanate compounds that can be used in the method of the present invention include tolylene diisocyanate, 4,4°-diphenylmethane diisocyanate and its polymer type (commonly known as polymeric MDI), trimethylene diisocyanate, tetramethane diisocyanate, and hexamethylene diisocyanate. J. Propylene glycol glycidyl ether, dibrobylene glycol glycidyl ether, other polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylpropane polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, dicarboxylic acid Examples include glycidyl ether, diglycidyldimethylhydantoin, glycidyltrimethylammonium chloride, furfuryl glycidyl ether, and bisphenol A diglycidyl ether.

Furthermore, examples of melamine derivatives include methylolated melamine, methylated melamine, and butylated melamine.

Foam curing can be carried out in the presence of a blowing agent under the same conditions as conventional urethane resins or epoxy resins, and the reaction conditions vary depending on the type of polyhydric alcohol, the substance to be reacted with it, etc. For example, when chemically modified wood such as methylated wood flour is dissolved in a polyhydric alcohol and then converted into a urethane resin, the solvolysis catalyst is neutralized, and then Shaolong water is added to form a polymeric isocyanate. When MDI is added, resinification with foaming occurs simply by heating or by self-heating at room temperature, even without adding a resinization catalyst, and the desired wood-based foamed resin can be obtained. . In addition, in this case, the presence of chemically modified wood not only serves as a substitute for polyol, but may also play an active role in contributing to improving the physical properties such as strength characteristics of the foam.
This was revealed by comparison with a control experiment lacking only chemically modified wood.

In order to further improve the performance of the resin foam obtained in this experiment, various additives can be added before resin formation.

For example, addition of low-molecular compounds or emulsifiers to improve solution properties such as viscosity and workability of polyhydric alcohol solutions for plasticized wood, addition of emulsifiers to improve the mixing state of the reagents used, and reactivity of isone anate compounds. addition of reaction blocking agents (such as solvents that do not dissolve in polyhydric alcohols) to improve It is possible to add a coloring agent for this purpose.

Effects According to the method of the present invention, due to the presence of the fibrous polymer, it is much easier to form a foamed resin than from a monomer or oligomer solution. In addition, the resulting foams are often superior in strength to comparable resin foams such as urethane resin foams and phenolic resin foams.

Furthermore, instead of using wood as a conventional filler or bulking material, we use compatibilized wood-based materials, which has a low specific gravity (
For example, in the example shown in the example, a foam with a specific gravity of 0.04 can be obtained.

Moreover, the presence of polymeric wood components in the walls of the foam provides high rigidity and toughness. With them, extremely useful foams are obtained which are highly thermally stable, dimensionally stable, vapor permeable and hygroscopic.

In addition, it has a wide range of applications, and can be adhesively foamed with wood or paper, and the products obtained in this way have high peel resistance.

In this manner, the present invention effectively utilizes wood-based raw materials to provide a foam with extremely excellent properties.

The present invention will be explained in more detail with reference to Examples below.

Example 1 (1) Preparation of methylated main flour 50 g of dried makamba wood flour (20-60 mesh) was weighed into a reaction flask of a simple reaction device with a capacity of 1 ml, and 500 J of toluene was added. Next, 40g of caustic soda
was added as a 40% aqueous solution, and 1
Stir at room temperature for a period of time to mercerize (alkali cellulose). Thereafter, 50 J of methyl iodide is added, the container is sealed, the temperature is raised to 80° C., and the reaction is carried out for 2 to 6 hours. When the stirring is stopped at the end of the reaction, the reaction system will separate into two layers, so remove the supernatant toluene by decanting, add a mixture of acetic acid and acetone/methanol (3:7 vol), stir, and neutralize and wash. After removing the supernatant, excess acetone was added in the same manner, washed twice with stirring, collected, air-dried, and further dried in a blower dryer at 60°C for 1 day. Then vacuum dry at 50°C to obtain a sample.

The resulting methylated wood flour has an orange-yellow color.
It is in the form of a powder whose appearance has not changed much.

The apparent weight increase rate is 8%.

(2) Solvolysis of methylated wood flour with hexamethylene glycolHexamethylene glycol (1,6-hexanediol, m, p, 42.8°C, b, p, 132.5°C) 5 g
is weighed into a 30 mfl round bottom flask, heated to 50°C to dissolve, and 5% (11% hydrochloric acid (35% pure hydrochloric acid aqueous solution)) is added to the diol.

After mixing thoroughly, 2.5 g of methylated wood flour obtained in (+) (6-hour methylated product) was added, and the mixture was left to stand at 80° C. for about 30 minutes, and then stirred in that state for 2.5 hours.

At the end of the process, the methylated powder is dissolved into a brown, viscous solution.

(3) Formation of foamed resin from solvolyzed methylated wood flour solution The hexamethylene glycol solution of methylated wood flour obtained as described above was immediately neutralized with a 40% aqueous solution of caustic soda, and the resulting solution was added to % polymeric MDI-toluene solution in the same volume ratio, mix well and heat to 100<0>C. Foaming begins after 2 to 3 minutes, and a foam is obtained in about 10 minutes. After defecation in a blow dryer at 100℃
After approximately 0 minutes, curing is almost complete and the specific gravity is approximately 0.04.
A pale yellow-brown foam is obtained. The strength is also satisfactory. When the above-mentioned foaming is carried out in a mold, a wood-based resin-converted foamed molding material is obtained. In this experiment, the water in the 35% hydrochloric acid aqueous solution added during sorbo rinsing and the water in the 40% caustic soda aqueous solution added during neutralization of the resulting solution functioned as blowing agents.

Example 2 (1) Preparation of methylated wood flour Methylated wood flour was prepared in the same manner as in Example 1 (1).

(2) Sorborins bisphenol A by bisphenol A of methylated wood flour [2,2-bis(4°-hydroxophenyl)propane; m, p, I 55 to I 5
6°C] 5g was weighed into a 30m round bottom flask,
Heated to 80°C and added 5% to bisphenol.
Add an aqueous solution of hydrochloric acid (35%) to dissolve. After mixing thoroughly, 5 g of methylated wood flour (2-hour methylated product) was added, and the mixture was left at 80°C for about 30 minutes, and then stirred in that state for 15 hours. At the end of the process, the methylated wood flour is dissolved into a dark brown viscous solution. When this solution is cooled to room temperature, it solidifies, so triethylamine is added in this dissolved state to neutralize it.

(3) Formation of foamed resin from solvolyzed methylated wood powder solution The above neutralized methylated wood-bisphenol A solution becomes solid when cooled to room temperature, so the volume ratio is 1
/2ffl of ethanol is added to obtain a solution that remains in a solution state even at room temperature. A 75% toluene solution containing 1 and 4 moles of 4,4-diphenylmethane diisocyanate (MDr) for the molar amount of bisphenol A added to this solution is added, mixed well, and heated to 80°C. When left standing in an oil bath at 80° C., foaming begins in about 2 minutes and stops in about 10 minutes to obtain a foam. When the above foaming is carried out in a mold, a wood-based resin foam molding material is obtained. In this case, the resulting foam has a high specific gravity of about 0.3 and is reddish brown in color.

Example 3 (1) Preparation of ethylated wood flour Dried Makamba wood flour (20-60 mesh) 50g216
o□. ,. Wa+5757. : Take 7 o's and add 500 J of toluene. Next, caustic soda 4
0g was added as a 40% aqueous solution, stirred at room temperature for 1 hour,
Perform mercerization. Then, 100 mfl of diethyl sulfate was added, the container was sealed, and the temperature was raised to 80°C for 3 to 6 hours.
Time reacts. After the reaction, the product was collected in a glass filter and mixed with acetic acid, acetone, methanol (3.7
Neutralize and wash with a vol) mixture, then thoroughly wash with an acetone/methanol mixture, drain, and air dry. then 6
A sample is obtained by blow drying at 0°C and further vacuum drying at 50°C. The obtained ethylated wood flour has a yellowish color,
It is in powder form with not much change in appearance.

(2) Sorbo rinse of ethylated wood flour with ethylene glycol ethylene glycol (1,2-ethanediol: m, p
, -115°C, b, p, 197°C) was weighed into a 30J round bottom flask, and 5%
(by weight) of an aqueous solution of hydrochloric acid (35%). After mixing well, add 5 g of ethylated wood flour (4-hour ethylated product), leave it at 80°C for about 30 minutes, and leave it in that state for 2 hours.
．． Stir for 5 hours. At the end of the process, the ethylated wood flour is dissolved into a brown viscous solution.

(3) Foaming resin from a solution of solbo-rinsed ethylated wood flour The ethylene glycol solution of ethyl wood flour obtained as described above was immediately neutralized with a 40% caustic soda aqueous solution, and the resulting solution was mixed with 75% polymeric MDI. - toluene solution,
Add in the same volume ratio, mix well, and heat to 120°C. 2
Foaming begins in about 7 minutes, turns into a resin, and stops foaming in about 7 minutes, yielding a foam. In this case, the resulting foam has a specific gravity of about 005 and a reddish brown color.

Example 4 (1) Preparation of ethylated main flour The ethylated main powder was prepared in the same manner as in Example 3 (1).

(2) Solvolysis of ethylated powder using a mixed solution of equal amounts of bisphenol A and butanediol Bisphenol A and butanediol (equal weights of each, total 5 g) were weighed into a 30J round bottom flask, heated to 80°C, and diol was added. Add an aqueous solution of 5% hydrochloric acid (35%) based on the amount to dissolve and mix well.

Then, add 25g of ethylated wood flour and heat at 80°C for about 30 minutes.
After standing for a minute, stir in that state for 1.5 hours. At the end of the process, the ethylated wood flour is dissolved into a brown viscous solution.

(3) Foamed resin of the solvolyzed ethylated wood flour solution The bisphenol A-butanol solution of the ethylated wood flour obtained as described above was neutralized with triethylamine, and the diol added to the resulting solution A 75% toluene solution containing 4.4'-diphenylmethane diisocyanate (MDI) in an amount 14 times the total number of moles of is added, mixed well, and heated to 100°C. When left standing at 100°C, foaming begins at about 1°C and stops at about 5°C, yielding a foam. In this case, the specific gravity of the resulting foam is
It is about 0.09 and has a brown color. It has relatively high strength.

Example 5 (1) Preparation of allylated wood flour Approximately 30 g of dried Macamba main flour (20-60 matsuyu) was placed in a ring, and 50 g of a previously prepared 40% caustic soda aqueous solution was added thereto. After stirring well, pressure was increased to squeeze out excess caustic soda aqueous solution. The weight of the alkali-treated water powder impregnated with the caustic soda aqueous solution was about 2 to 3 times that of the wood powder before treatment.

Next, the obtained alkali-treated main powder was transferred to a stainless steel pressure-resistant reaction tube, 09 mJl of allyl bromide I was added thereto, and the mixture was reacted at 80°C for 3 hours. After the reaction was completed, the reaction product was poured into an excess methanol/water (1:4) mixture and thoroughly washed several times with the same wave.

Finally, after collecting one sample with a glass filter (G-2), -
After drying with blow air, the sample was further vacuum-dried at 70'C day and night to obtain an allylized wood flour sample. The product had a yellow color and an apparent weight increase of 28%.

(2) Hexamethylene glycol in allylated wood flour
Weigh out 10 g of solvolysis hexamethylene glycol (I, 6-hexanediol) according to 1 into a 50 m4 round bottom flask,
Heat to 0°C to dissolve, then add 35% hydrochloric acid aqueous solution 1
．． Add 2m4 and mix well.

Thereafter, 7 g of allylated wood flour was added, and the mixture was allowed to stand at 100° C. for 30 minutes, and then stirred in that state for 1.5 hours. At the end of the process, the allylated wood flour is dissolved into a brown viscous solution.

(3) Formation of foamed resin from solvolyzed allylated wood flour The hexamethylene glycol solution of the allylated wood flour obtained as described above was neutralized with a 40% caustic soda aqueous solution, and the resulting solution was mixed with 75% polymeric MDI. Add the toluene solution in an equal volume ratio, mix well, place in an aluminum foil mold, place on a hot plate controlled at 130°C, and heat for 7 minutes. During that time, foaming begins and resin formation progresses. A foam molded product is obtained. This material is further placed in a blow dryer at 100° C. and heated for 15 minutes for post-curing.

The obtained foam exhibits a pale yellow color with a specific gravity of 0.04, and has sufficient strength for use as a heat insulating agent.

Example 6 (1) Preparation of allylated main flour Allylated wood flour was prepared in the same manner as in Example 5 (1).

However, the allylation time was set to 2 hours.

(2) 5g of sorbolin bisphenol A and 5m of ethanol using a mixture of bisphenol A and ethanol from allylated main powder! , , 30m
Weigh out 1 fl of a 35% aqueous hydrochloric acid solution into a round bottom flask.
．． Add 2mK (5% by weight of alcohol) and mix well. At that time, stir slightly in an 80°C oil bath,
Allow bisphenol A to completely dissolve. Next, 5 g of allylated main flour was added and left at 80°C for 20 minutes.
The mixture was stirred for a minute. At the end of the process, the allylated wood flour is dissolved into a reddish-brown viscous solution.

(3) Formation of solvolyzed allylated wood flour into a foamed resin The solution of the allylated wood flour obtained as described above,
Neutralize with triethylamine and make an equal volume of 75% of the solution.
After adding tolylene diisocyanate and stirring well, 1
Heat at 20°C. Resin formation accompanied by foaming begins in 1 to 2 minutes, and foaming ends after 7 minutes. Subsequently, post-curing was performed in a blow dryer at 60° C. to obtain an allylized wood powder resin foam.

This material has a specific gravity of about 0.2 and is a brown, strong foam.

Example 7 (1) Preparation of acetylated wood flour 2.8 J of acetic anhydride and 17.5 J of acetic acid were added to 10 g of dried wood flour (Macamba 20-60 mesh), and the mixture was left at room temperature overnight. Next, 59.4 J of acetic anhydride, 3 J of acetic acid
2.0+ni, 0.128ml perchloric acid. The acylating agent mixed with is cooled to around -10°C and added to the pretreated wood flour. The reaction is carried out in a 300 m, 9-meter round bottom separable flask. After injecting the mixed acid, the mixture is left at room temperature for 1 hour, and then the temperature of the constant temperature bath is started to reach a predetermined temperature of 30 to 45°C. Stir with a stirrer during the reaction. The reaction time was 6 hours in total. After the reaction is complete, wash thoroughly with water, filter with a G~2 glass filter, and dry with air at 60°C (-night).
The powder was dried under vacuum at 50° C. (day and night) to obtain an acetylated powder. The product had the same appearance as the starting wood flour, with an apparent weight increase of 25%.

(2) Sorbo rinse of acetylated wood flour with ethylene glycol Weigh out 10 g of ethylene glycol into a 30 mfl round bottom flask, warm it to 50°C, then add 1.23 J of 35% aqueous hydrochloric acid solution and mix well. do. Thereafter, 5 g of acetylated wood flour was added, and the mixture was allowed to stand at 100° C. for 30 minutes, and then stirred in that state for 1.5 hours. At the end of it,
Acetylated wood flour is dissolved into a bluish-black viscous solution.

(3) Making foamed resin from solvolyzed acetylated wood flour
i. Neutralize the acetylated wood flour solution obtained as above with triethylamine, then add an equal volume of 75% polymeric MDI toluene solution to the acetylated wood flour solution and mix well. and heat to 120°C. Foaming starts after 2 to 3 minutes, the resin is formed, and a foam is obtained in about 10 minutes. Approx. 2 in a blow dryer at 60℃
It is cured after 0 minutes to obtain a resinized foam. The product has a specific gravity of 0
．． It is a resin-like substance that exhibits a yellow color of about 0.09.

Example 8 (1) Bisphenol A in methylated wood flour obtained in Example 2
Caustic soda '4θ% instead of triethylamine in the solution
Add aqueous solution to make alkaline.

(2) Formation of foamed resin from solbo-rinsed methylated wood flour solution. Approximately 2/3 of the weight of epichlorohydrin is added to the methylated wood flour solution obtained as described above, and the mixture is heated to cause a reaction. After polyglycidylation, triethylenetetramine, which is about 1/3 by weight of the previously added epichlorohydrin, was added, and at the same time, 5% by weight of sodium bicarbonate was added to the solution, stirred, and heated to +10'C. Heat.

Resin formation accompanied by foaming begins in a few minutes, and a foam is obtained. Furthermore, it is cured in that state for 3 hours to obtain a resinized foam. The product has a specific gravity of about 0.2 and is a yellowish brown resin-like substance.

Example 9 (1) Triethylamine is added to the hexamethylene glycol solution of the methylated wood flour obtained in Example 1 to neutralize it.

(2) Formation of foamed resin from solbo-rinsed methylated wood flour solution To the methylated wood flour solution obtained as described above, add an equal amount by weight of diethylene glycol diglycidyl ether, and further add triethylamine to make the solution alkaline. Add 5% by weight of sodium carbonate to the mixture and heat to 150°C. Resin formation accompanied by foaming begins in a few minutes, and a foam is obtained. Further, it is cured in this state for 1 hour to obtain a resinized foam.

The product is a sponge-like flexible foamed resin body with a specific gravity of about 0.2 and a yellowish brown color.

Example lo (1) The ethylated wood flour obtained in Example 4 is used to perform phenolysis. Weigh out 10 g of phenol into a 30 ml round bottom flask, heat it to 60°C to melt it, and then
Add 1.23 m of 5% aqueous hydrochloric acid solution and mix. Then, add 5 g of ethylated wood flour and let it stand at 80°C for 30 minutes, then stir in that state for 30 minutes. At the end of the process, the ethylated wood flour is It dissolves into a brown viscous solution.

(2) Formation of foamed resin from solvolyzed ethylated wood flour The ethylated wood flour solution obtained as described above was made alkaline with a 40% caustic soda aqueous solution, and then formalin (
A 40% aqueous solution) was added in an equal volume to the ethylated wood flour solution and reacted at 100° C. for 60 minutes under stirring. At the end of the process, a brown viscous ethylated wood powder modified resol is obtained. Next, when 30% phenolsulfonic acid and 5% petroleum ether by weight were added and stirred, foaming started due to the vaporization of the ether due to self-heating due to condensation in a few minutes, and a resinized foam was formed in about 20 minutes. is obtained. 1 more
Post-cure for 2 hours at 20°C. The specific gravity of the product is 0.03
It is a resin-like substance that is light brown in color.

Claims (1)

[Scope of Claims] 1. A wood foam obtained by foaming and curing a solution in which chemically modified wood is dissolved in an organic solvent having an active group that can be polymerized. 2. It is characterized by dissolving the chemically modified wood in an organic solvent having an active group that can be polymerized, and then adding a crosslinking agent or a curing agent and, if necessary, a foaming agent to the solution and foaming and curing it. Method for manufacturing wood foam.