JP3409092B2 - Thermosetting chemically modified wood material composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically modified wood material composition having excellent thermoformability and excellent heat moldability.

[0002]

2. Description of the Related Art Wood materials represented by wood are organic natural resources that are most abundant in nature and have excellent mechanical properties and processability. Used in large quantities. However, although small-diameter trees, thinned wood, sawdust, sawdust, etc. discharged from wood factories are used in the production of particle boards and wood fiber boards, most of them have been discarded by methods such as incineration. It was

As a method of effectively utilizing these wood materials,
Attempt to use wood as a solution in a chemical and use it as an adhesive or foam, study how to effectively use the components in wood, or chemically modify wood to impart thermoplasticity to it. Utilization as various molding materials is being actively studied.

As a method of chemically modifying the wood material to impart thermoplasticity, a method of allylating or benzylating the wood material by reacting allyl halide, benzyl chloride or the like,
A method of reacting higher fatty acid or its anhydride to acylate wood, a method of reacting an epoxy compound to etherify wood, or an oligoester of wood using a monoepoxy compound and a polybasic acid anhydride Various methods such as a method for converting into a chemical have been proposed, and it has been reported that the chemically modified wood material obtained by these methods can be easily molded by a thermocompression molding method or the like. However, simply molding a chemically modified wood material with thermoplasticity is mechanical,
It is not practically satisfactory in terms of physical properties and the like.

In order to solve these problems, by using a chemical substance having a polymerizable double bond in the molecule in the above method, it is possible to introduce a polymerizable double bond into the wood material, so that it is possible to carry out thermocompression molding. It is known that polymerization of double bonds and plasticization of chemically modified wood material occur at the same time to obtain a molded article having excellent mechanical and physical properties. However, in this case, it is necessary to mix a peroxide generating a radical such as dicumyl peroxide, and moreover, because of the inhibitory effect on the polymerization of the phenol derivative due to lignin in the wood, peroxide is usually used. However, there is a problem that it is difficult to cure when the compounding amount is used.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and has a high wood content without the use of peroxides and is excellent in heat moldability and thermosetting property. An object is to provide a chemically modified wood material composition.

[0007]

According to the present invention, in a composition comprising a chemically modified wood material and a curing agent, the wood material-derived tetrahydrofuran having the maximum absorption in the ultraviolet region of 220 nm to 300 nm is used. (THF)
A thermosetting chemically modified wood material composition is provided, which contains a soluble component, wherein the curing agent generates formalin by heating, and the chemically modified wood material, There is provided the thermosetting chemically modified wood material composition, characterized in that an exploded wood material is used, and the chemically modified wood material has an inorganic acid having a pKa of 3 or less or a pKa of 1 or less. In the presence of the organic acid, the thermosetting chemically modified wood material composition, characterized in that the wood material is a monoepoxy compound or a monoepoxy compound and a polybasic acid anhydride are reacted, Further, the curing agent is provided with the thermosetting chemically modified wood material composition, wherein the composition is hexamine or paraformaldehyde, and further, to the thermosetting chemically modified wood material,
Further, there is provided a thermosetting chemically modified wood material composition, which comprises a compound which is phenol, melamine, urea or a derivative thereof and which can undergo an addition condensation reaction with the curing agent.

[0008] That is, the inventors of the present invention
A composition comprising a chemically modified wood material containing a THF-soluble component derived from wood material having a maximum absorption in 20 nm to 300 nm and a curing agent that generates formalin by heating does not use a peroxide or the like during heat molding. It was found that the compound can be easily heat-cured and has excellent heat moldability, and has completed the present invention.

The present invention will be described in detail below. The wood material referred to in the present invention includes wood powder, wood fiber, wood chips, and
Not only wood particles such as sander powder discharged during the manufacturing process of particleboard, fiberboard and the like, but also lignocellulosic materials such as plant fibers such as straw, rice straw, chaff, bagasse and the like are included. Such a wood material can be used as it is as a raw material for the chemically modified wood material, but 220 nm to 3 in the ultraviolet region of the chemically modified wood material is used.
The larger the amount of the wood-soluble THF-soluble component having the maximum absorption at 00 nm, the better the heat moldability and thermosetting property. Therefore, in order to increase the content of the soluble component, pretreatment such as blasting treatment is performed. It is particularly preferable to use after applying. By this blasting treatment, lignin in the wood material is decomposed and the THF-soluble component increases.

The method for producing the chemically modified wood material includes, for example, esterification treatment with acetic anhydride or trifluoroacetic anhydride and lauric acid, oligoesterification treatment with polybasic acid anhydride and monoepoxy compound, cyanoethyl with acrylonitrile. Known methods such as chemical treatment and etherification treatment with a monoepoxy compound can be applied without particular limitation. As a method for increasing the THF soluble component derived from wood, there are methods such as increasing the reaction temperature, lengthening the reaction time, and increasing the amount of chemical substances added to the wood, but the pKa is 3 The following inorganic acids, or pK
When a wood material is chemically modified in the presence of an organic acid having a of 1 or less, decomposition of lignin in the wood material is likely to occur, and thus the THF-soluble component derived from the wood material of the chemically modified wood material obtained tends to increase. Therefore, it is preferable. Particularly, a chemically modified wood material obtained by reacting a monoepoxy compound or a monoepoxy compound with a polybasic acid anhydride in the presence of the above-mentioned acidic substance is preferable because it has excellent heat fluidity and heat moldability.

Here, as the monoepoxy compound used for the chemical modification treatment, allyl glycidyl ether, butyl glycidyl ether, etc., and as the polybasic acid anhydride,
Examples thereof include succinic anhydride, maleic anhydride, and Pk.
Phosphoric acid or the like can be used as the inorganic acid having a3 or less, and trichloroacetic acid or the like can be used as the organic acid having PKa1 or less.

The THF-soluble component derived from wood having a maximum absorption in the UV region of 220 nm to 300 nm in the obtained chemically modified wood is mostly lignin which has a three-dimensional structure in the wood and is decomposed. It is considered to be a low molecular weight phenol derivative, which is usually soluble in organic solvents,
Although it has thermal fluidity, it is evaluated as the amount of the THF-soluble component in the present invention for the reason of measuring the ultraviolet absorption spectrum. Therefore, as the amount of the THF-soluble component increases, the heat fluidity and thermosetting property of the chemically modified wood material improve. The content of the THF soluble component derived from the wood material is contained in 1 g of the chemically modified wood material by immersing the chemically modified wood material in THF and measuring the resulting THF solution with an ultraviolet absorption spectrum measuring device. It can be evaluated by converting the soluble component into an optical density of a solution obtained by dissolving 1000 ml of THF. The optical density log ₁₀ I
₀ / I is the Lambert-Be expressed by the following formula (Equation 1).
It is obtained from er's law. In the present invention, a chemically modified wood material containing a THF-soluble component derived from wood material having a maximum absorption in the ultraviolet region of 220 nm to 300 nm is
It refers to a chemically modified wood material having an optical density of 1.0 or more at a wavelength exhibiting maximum absorption.

[0013]

## EQU1 ## log ₁₀ I ₀ / I = εcl ε: Absorption coefficient of sample c: Concentration of sample l: Cell thickness (cm)

The percentage of wood material in the chemically modified wood material varies depending on the reagent and method used for the chemical modification treatment, but it is preferably in the range of approximately 30 to 85% by weight, particularly 30.
It is preferably in the range of ˜70% by weight. Wood material ratio is 8
If it exceeds 5% by weight, the heat flowability of the chemically modified wood material is poor (the melt index (M
Measurement of I) is impossible. ) It is not preferable because heat molding becomes difficult. Further, when the woody material ratio is less than 30% by weight, the heat fluidity is excellent, but the woody material ratio is too low to achieve the object of the present invention and is economically unfavorable.

The other component in the thermosetting chemically modified wood material composition of the present invention, which is a curing agent for generating formalin upon heating, is conventionally known as a curing agent for phenol resin, melamine resin, urea resin and the like. Known hexamine, trioxane, paraformaldehyde and the like are mentioned, and hexamine and paraformaldehyde are particularly preferable because they are easy to handle and have good curing performance. The blending amount of these is 3 with respect to 100 parts by weight of the above chemically modified wood material.
-40 parts by weight is preferred. If the blending amount is less than this, the thermosetting property of the obtained composition is poor, and conversely if the blending amount is large, the thermosetting property is excellent, but a large amount of unreacted curing agent remains in the cured product, which is not preferable.

Further, the thermosetting chemically modified wood material composition of the present invention may be further subjected to addition condensation reaction with phenol, melamine, urea or a derivative thereof (for example, resorcinol), with the curing agent. A compound can be added to improve the thermosetting property. The addition amount of these is 3 to 10 relative to 100 parts by weight of the chemically modified wood material.
0 parts by weight is preferable, and if it is less than this range, the effect of addition cannot be expected so much, and conversely if it is more than that, the rate of wood material in the composition becomes low, and the object of the present invention is not achieved.

In addition, internal release agents such as zinc stearate and various thermosetting resins, and fibers such as glass fibers, acrylic fibers, aramid fibers and carbon fibers, flame retardants, colorants and the like, if necessary. Can be added.

Such a chemically modified wood material composition is hardened by heating, because the THF soluble component derived from wood material (maximum absorption in the UV region of 220 nm to 300 nm in the chemically modified wood material (large It is assumed that the portion is a phenol derivative.) And reacts with these curing agents to crosslink.

The thermosetting chemically modified wood material composition of the present invention is the above-mentioned chemically modified wood material and a curing agent, or further phenol, melamine, urea or a derivative thereof, which can undergo an addition condensation reaction with the curing agent. It can be prepared by uniformly kneading the compound using a kneader such as a blender, a kneader, a mixing roll and a Banbury mixer. The obtained thermosetting chemically modified wood material composition of the present invention has good heat fluidity and thermosetting property, and therefore, as well as general press molding, extrusion molding, ordinary molding by injection molding, etc. It can be molded under the processing conditions for molding a curable resin, and is suitable as an industrial part material, building material, etc. in many fields.

[0020]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, wood powder (trade name: LIG
NOCEL S150TR; Rettenmari
er &Soehne; fiber length: 30-60
μ) and exploded wood powder (lauan wood was steamed in saturated steam of 30 kg / cm ² for 2 minutes and then rapidly depressurized).

The evaluation was performed by the following method. <Optical Density> The optical density indicates the amount of the THF-soluble component derived from the wood material in the chemically modified wood material. The measurement was performed by immersing 1 g of the chemically modified wood material in 5 ml of THF, diluting the obtained THF solution 1000 times, measuring with an ultraviolet absorption spectrum measuring device, and then calculating based on the above formula (Equation 1). . <THF-soluble part> Represents the proportion of the THF-soluble component in the chemically modified wood material. The wood material component became soluble in THF by chemical modification, and side reaction products not bound to the wood material component. Contains things. <Heat Formability> The heat formability of the chemically modified wood material was evaluated by MI, which represents thermal fluidity. MI is JIS K7210
The sample was measured at 150 ° C. or 190 ° C. under a sample load of 10 kg, and was expressed as a value flowing out in 10 minutes. <Shore hardness> Thermosetting chemically modified wood material composition
The thermosetting property was evaluated by measuring the Shore hardness of the molded product obtained by thermocompression molding at 50 ° C. for 30 minutes. <Bending Strength> The molded product obtained by heat-curing at 130 ° C. for 30 minutes is taken out from the mold, and is further cured at 150 ° C. for 24 hours. The bending strength of the molded product is determined according to ASTM K790-81.
Was measured according to.

Production Example 1 Wood flour 1000 g, pre-reacted allyl glycidyl ether (538 g) and 85% phosphoric acid aqueous solution (138 g)
A chemically modified wood material A was obtained by charging the mixture with and into a 5 l reaction vessel and reacting at 150 ° C. for 3 hours with stirring. Table 1 shows the content of the THF-soluble portion, the measurement result of the ultraviolet absorption spectrum, and MI of this chemically modified wood material A. FIG. 1 shows U of the THF-soluble component in the chemically modified wood material A.
The V spectrum is shown.

Production Example 2 18.8 g of wood flour, pre-reacted allyl glycidyl ether (13.07 g) and 85% phosphoric acid aqueous solution (3.4
5 g) of the mixture was charged into a 500 ml reaction vessel,
After reacting at 0 ° C for 2 hours with stirring, succinic anhydride (5.73
g) was added and reacted at 150 ° C. for 5 hours to obtain a chemically modified wood material B. The content of the THF soluble portion of this chemically modified wood material B, the measurement result of the ultraviolet absorption spectrum, and M
I is shown in Table 1. Figure 1 shows TH in chemically modified wood material B.
The UV spectrum of F soluble component is shown.

Production Example 3 A mixture of 1000 g of wood flour, pre-reacted allyl glycidyl ether (428 g) and 85% phosphoric acid aqueous solution (92 g) was placed in a 5 liter reaction vessel and reacted under stirring at 150 ° C. for 3 hours. By doing so, a chemically modified wood material C was obtained.
Table 1 shows the content of the THF-soluble part, the measurement result of the ultraviolet absorption spectrum, and MI of this chemically modified wood material C.

Production Example 4 18.8 g of wood flour, pre-reacted butyl glycidyl ether (12.53 g) and 85% phosphoric acid aqueous solution (3.2
5 g) of the mixture was charged into a 500 ml reaction vessel,
A chemically modified wood material D was obtained by reacting at 0 ° C. for 7 hours with stirring. Table 1 shows the content of the THF-soluble part, the measurement result of the ultraviolet absorption spectrum, and MI of this chemically modified wood material D.
It was shown to.

[0026]

[Table 1]   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━                                   Chemical study Decorative wood materials                                A B C D   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━   Wood material ratio (% by weight) 60 46 66 55   Wavelength showing maximum absorption (nm) 240 240 240 240   Optical density 3.7 3.3 2.9 2.8   Content of THF-soluble part (wt%) 53 83 49 57   MI (10kg, 10 minutes) 72a 170a 0.56a 2000b   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ a) Measured at 150 ° C b) Measured at 190 ° C

Production Example 5 20 g of exploded wood powder, 40 g of acetic anhydride, and 5 g of potassium acetate were placed in a 500 ml separable flask and charged to 150
After stirring at ℃ for 3 hours, by-product acetic acid was removed under reduced pressure to obtain a chemically modified wood material E. The chemically modified wood material E had a wood material ratio of 55% by weight, an optical density of the THF-soluble portion was 2.1, and a content of the THF-soluble portion was 49% by weight.

Production Example 6 20 g of exploded wood powder was immersed in 30 ml of a 4% sodium hydroxide aqueous solution dissolved in a saturated sodium thiocyanate aqueous solution for 30 minutes, 30 g of acrylonitrile was added, and the mixture was mixed at 40 ° C. for 3 days.
Reacted for hours. The product was neutralized with an aqueous acetic acid solution and then filtered to obtain cyanoethylated wood flour. This is 2.
It was immersed in 50 ml of 1 mmol / l chlorine water overnight for chlorine treatment, filtered and dried to obtain a chemically modified wood material F having a wood material ratio of 50% by weight. This chemically modified wood material F
The THF-soluble part had an optical density of 1.3, and the THF-soluble part content was 13% by weight.

Production Example 7 15.92 g of maleic anhydride was added to 40 g of dried exploded wood powder.
Was added and reacted at 120 ° C. for 2 hours, then 24.08 g of allyl glycidyl ether was added and further reacted for 5 hours to obtain a chemically modified wood material G. The woody material ratio of this chemically modified woody material G was 50% by weight, the optical density of the THF-soluble part was 2.9, and the content of the THF-soluble part was 36% by weight.

Production Example 8 In a 500 ml separable flask were placed 18.8 g of wood flour and 13.07 g of allyl glycidyl ether at 150 ° C.
After the reaction for 2 hours at 5.70 g, succinic anhydride (5.73 g) was added, and the reaction was continued for 5 hours to obtain a chemically modified wood material H.
This chemically modified wood material H has a wood material ratio of 50% by weight, THF
The optical density of the soluble portion is 0.29, and the content of the THF soluble portion is 3
It was 4% by weight. It is considered that the reason why the chemically modified wood material H has a low optical density is that the by-product obtained by reacting allyl glycidyl ether not bound to wood material and succinic anhydride occupies most of the THF-soluble portion. FIG. 1 shows a UV spectrum of a THF-soluble component in the chemically modified wood material H.

Production Example 9 20 g of wood flour, 40 g of acetic anhydride, and 5 g of potassium acetate
In a 500 ml separable flask at 150 ° C
After the reaction was carried out for 3 hours, the by-product acetic acid was removed under reduced pressure to obtain a chemically modified wood material I. This chemically modified wood material I
The woody material ratio was 55% by weight, the optical density of the THF-soluble portion was 0.36, and the content of the THF-soluble portion was 25% by weight.

[0032]

[Table 2] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Chemical science Decorative wood Wood material E F G H * ━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Wood material ratio (% by weight) 55 50 50 50 Wavelength at which maximum absorption (nm) 240 240 239 239 Optical density 2.1 1.3 2.9 0.29 Content of THF soluble part (wt%) 49 13 36 34 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ (* Chemical modification The wood material H has an ultraviolet range of 220 nm to 3
It does not substantially contain a wood-derived THF-soluble component having a maximum absorption at 00 nm. )

Examples 1 to 3 A thermosetting chemically modified wood material composition was prepared by mixing a predetermined amount of a curing agent (hexamine, paraformaldehyde) into the chemically modified wood material A using a test roll. This composition was placed in a mold and hot pressed at 150 ° C. for 30 minutes to obtain a molded product. This molded product was hard when it was hot pressed. Table 3 shows the Shore hardness and the bending strength.

Comparative Example 1 The chemically modified wood material A was put into a mold as it was, and the mixture was heated at 150 ° C. for 3 hours.
A molded product was obtained by hot pressing for 0 minutes, but it was soft and not practical because no curing agent was used. Table 3 shows the Shore hardness and the bending strength.

Comparative Example 2 100 parts by weight of chemically modified wood material A was mixed with 3 parts by weight of dicumyl peroxide using a test roll. This composition was placed in a mold and hot pressed at 150 ° C. for 30 minutes to obtain a molded product. Hardening proceeded in spite of the introduction of the polymerizable double bond in the chemically modified wood material. I didn't. Table 3 shows the Shore hardness and the bending strength.

[0036]

[Table 3] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Chemically modified wood material A (weight part) 100 100 100 100 100 Hexamine (parts by weight) 10 20 Paraformal aldehyde (parts by weight) 5 DCPO a) (parts by weight) 3 Percentage of wood material (% by weight) 55 50 58 58 60 59 Shore hardness D30 D30 D25 A10 A10 Bending strength (kg / cm) ² ) 89 95 114-b) -b) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ a) DCPO: The dicumyl peroxide b) molded product was so soft that it could not be taken out of the mold.

Examples 4 to 7 Chemically modified wood materials A, B and C were mixed with urea or melamine in addition to a predetermined amount of a curing agent using a test roll to prepare a thermosetting chemically modified wood material composition. did. This composition was placed in a mold and hot pressed at 150 ° C. for 30 minutes to obtain a molded product. This molded product was hard when it was hot pressed. The Shore hardness is shown in Table 4.

Comparative Example 3 Hexamine (10 parts by weight) was mixed with 100 parts by weight of the chemically modified wood material H using a test roll. This composition was placed in a mold and hot-pressed at 150 ° C. for 30 minutes, but 220 to 300 n in the ultraviolet region in the chemically modified wood material used.
Since the soluble component derived from the wood material having the maximum absorption in m was extremely small, as shown in Table 4, it was not cured and was soft.

[0039]

[Table 4] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━                           Example 4 Example 5 Example 6 Example 7 Comparative Example 3 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Chemically modified wood material A (weight part) 100 100 Chemically modified wood material B (weight part) 100 Chemically modified wood material C (weight part) 100 Chemically modified wood material H (weight part) 100 Hexamine (parts by weight) 20 20 10 10 10 Urea (parts by weight) 10 Melamine (parts by weight) 10 Wood material ratio (% by weight) 47 47 42 60 45 Shore hardness D20 D45 A60 D40 uncured ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Examples 8 to 11 Thermosetting chemically modified wood material compositions were prepared by mixing 10 parts by weight of hexamine, which is a curing agent, into the chemically modified wood materials D to G using a test roll. This composition was placed in a mold and hot pressed at 150 ° C. for 30 minutes to obtain a molded product. This molded product was hard when it was hot pressed. The Shore hardness is shown in Table 5.

[0041]

[Table 5]     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━                                 Example 8 Example 9 Example 10 Example 11     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━       Chemically modified wood material D (weight part) 100       Chemically modified wood material E (weight part) 100       Chemically modified wood material F (part by weight) 100       Chemically modified wood material G (weight part) 100       Hexamine (parts by weight) 10 10 10 10       Wood material ratio (% by weight) 50 50 45 46       Shore hardness D15 D45 A80 D40     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0042]

EFFECTS OF THE INVENTION The thermosetting chemically modified wood material composition of the present invention has a high wood material content and is excellent in heat moldability and thermosetting property.
It can be molded by extrusion molding, injection molding or the like under the processing conditions for molding a usual thermosetting resin, and is suitable as an industrial part material, a building material and the like in many fields.

[Brief description of drawings]

FIG. 1 is an ultraviolet absorption spectrum of a THF solution of a chemically modified wood material.

[Explanation of symbols]

a) THF solution of chemically modified wood material A b) THF solution of chemically modified wood material B c) THF solution of chemically modified wood material H

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Matsuda ▲ Hide ▼ 1515 Nakatsu-cho, Marugame-shi, Kagawa Okura Industry Co., Ltd. (56) Reference JP-A-60-83806 (JP, A) JP-A-4 -156302 (JP, A) JP-A-5-185405 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B27K 5/00

Claims (5)

(57) [Claims] 1. A composition comprising a chemically modified wood material and a curing agent, wherein the chemically modified wood material is 220 nm in the ultraviolet region.
A thermosetting chemically modified wood material composition containing a tetrahydrofuran-soluble component derived from wood material having a maximum absorption at ˜300 nm, wherein the curing agent generates formalin by heating. 2. The thermosetting chemically modified wood material composition according to claim 1, wherein the chemically modified wood material is an exploded wood material. 3. The chemically modified wood material reacts the wood material with a monoepoxy compound or a monoepoxy compound and a polybasic acid anhydride in the presence of an inorganic acid having a pKa of 3 or less or an organic acid having a pKa of 1 or less. The thermosetting chemically modified wood material composition according to claim 1, which is a cured product. 4. The thermosetting chemically modified wood material composition according to claim 1, wherein the curing agent is hexamine or paraformaldehyde. 5. The thermosetting chemically modified wood material according to any one of claims 1 to 4, further comprising a compound which is phenol, melamine, urea or a derivative thereof and which can undergo an addition condensation reaction with the curing agent. A thermosetting chemically modified wood material composition characterized by: