JPS6032605A - Manufacture of woody molded item - Google Patents

Abstract

PURPOSE:To obtain the titled molded item whose surfaces are tough and hard, and that is dense and excellent in heat resistance, wear proofness, dimensional stability, etc., by mixing a woody material such as wood flour or the like with a special compound containing acid anhydride groups, and molding the mixture under heat and pressure. CONSTITUTION:Trimellitic acid ester anhydride of formula I (wherein R1 represents a glycol residue) or pyromellitic acid ester anhydride (A) having more than one acid anhydride group of formula II [wherein R2 represents a (poly)alkylene glycol residue, or a polyhydric alcohol residue having 3 or 4 OH groups, and (n) is 1-3] is added to a woody material (B) comprising wood flour, wood chips or wood fibre, and they are intimately stirred. Then the mixture is molded under heat and pressure to obtain the intended item. It is preferable to mix the constituents (A) and (B) at or over the softening or melting point of the constituent (A). EFFECT:According to the composition of the mixture, the obtained item has a glossy plastic appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses wood materials such as wood chips, wood fibers, or wood flour as raw materials, and has a surface that is tough, hard, and dense, and also has heat resistance, abrasion resistance, and size. This article relates to a method for manufacturing wood-based molded products with excellent stability.

Fossil resources such as oil and coal are currently used in large quantities as industrial raw materials, but their reserves are limited and there are concerns about their future prospects. On the other hand, wood is a renewable resource and has been used in various fields. However, no progress has been made in the effective use of small-diameter trees, thinned wood, and unused wood, and even more effective methods are being developed for small pieces of wood, such as wood powder, which are produced as by-products as industrial waste that uses wood. The current situation is what is desired. One of the conventional methods of using these materials is to mix small pieces of wood, especially wood flour, into plastics such as thermoplastic resins and thermosetting resins and use them as fillers and extenders. well known.

However, in such applications, the wood flour is physically mixed with these resins and is merely incorporated therein in a dispersed state. As the amount of wood flour added to the resin increases, the number of hydroxyl groups in the wood that have the ability to adsorb water increases, and the resulting plastic molded product tends to have poor dimensional stability due to water absorption and moisture absorption. Can be seen.

Therefore, there is a limit to the amount of wood flour that can be mixed into plastics as a filler or extender.

In addition, wood is a compound with low thermoplasticity, and it does not melt when heated like thermoplastic plastics do, so plastic molded products obtained by mixing wood flour with resin retain the shape of the wood flour. This appears in the appearance, with a decrease in surface smoothness and gloss. Furthermore, a decrease in mechanical strength and hardness of the plastic molded product is observed.

On the other hand, while chemical treatment of cellulose has been carried out for quite some time, the practical application of chemical treatment of wood can be said to be underdeveloped. The most likely cause of this problem is that the chemical reactivity of wood is extremely low. Wood is compositionally and structurally very different from cellulose. That is, wood is mainly composed of highly crystalline cellulose with a degree of crystallinity of about 60 to 70q6, lignin, an ultra-large polymer having a three-dimensional network structure, and hemicellulose, an amorphous substance. Therefore, it was thought that the chemical reactions that occur in cellulose are extremely difficult to react with in wood.

In view of the above-mentioned situation, the present inventors added a compound having an acid anhydride group to a wood material and heated and pressurized it, and the hydroxyl group in the wood undergoes an esterification reaction with the acid anhydride group in the compound, resulting in an addition bond. Focusing on its ability to produce synthetic wood products, we conducted extensive research into its uses, and found that trimellitic acid ester anhydride, represented by the general formula ■ (where R1 represents a glycol residue) (L, & represents an alkylene glycol residue, a polyalkylene glycol residue, or a polyhydric alcohol residue having 3 to 4 hydroxyl groups in the molecule. n represents an integer of 1 to 3.) Pyromellitic acid acid ester anhydride having at least two anhydride groups in the molecule represented by is added to a wood material selected from wood chips, wood fibers, or wood flour, and after thoroughly mixing these, the Mixing 6- Hot-pressing the product, or placing the mixture on a substrate and hot-pressing the mixture, or alternatively, forming the trimellitic acid ester anhydride shown in the above general formula I or the above general formula I The pyromellitic acid acid ester anhydride shown in Figure 1 is added to a wood material selected from wood chips, wood fibers, or wood flour.At this time, bisepoxide is added and, after thorough mixing, the mixture is heated. The inventors have discovered that a wood-based molded product with excellent properties, the main component of which is wood, can be obtained by pressure molding or by placing the mixture on a base material and hot-pressing it, leading to the present invention. It was.

That is, the present invention relates to trimellitic acid ester anhydride shown in the above general formula I or pyromellitic acid acid ester anhydride shown in the above general formula (2) (hereinafter referred to as trimellitic acid ester anhydride and pyromellitic acid acid ester anhydride). (collectively referred to as ester anhydride) are added to the wood material, and after thoroughly mixing these, the mixture is hot-press molded, or the mixture is placed on a base material and hot-press molded. By this,
The hydroxyl group in the wood material is bonded to the anhydride group in the ester anhydride through a ring-opening esterification reaction, and the ester anhydride has at least two anhydride groups in its molecule, so the wood material The present invention provides a method for producing wood-based molded products characterized by cross-linking via ester anhydrides.

In addition, when the above mixture of ester anhydride and wood material is placed on a wood base material and hot-press molded, the hydroxyl groups in the wood on the surface layer of the wood base material are combined with the anhydride groups of the ester anhydride and the ring-opened ester. Because the ester anhydride has at least two acid anhydride groups in its molecule, it is possible for the wood base material to be cross-linked with the wood material through the ester anhydride. It provides a manufacturing method for characteristic wood-based molded products.

Furthermore, the ester anhydride is added to the wood material, and at this time, the bis-epoxide is added and the mixture is thoroughly mixed, and then the mixture is hot-pressed or the mixture is placed on a substrate. By hot-pressing, the hydroxyl group in the wood material undergoes a ring-opening esterification reaction with the anhydride group in the ester anhydride to form a carboxyl group, or the pyromellitic acid ester anhydride. It is an addition bond formed by an esterification reaction between the carboxyl group present in the molecule of the bis-epoxide and the epoxy group in the bis-epoxide, and since the bis-epoxide has two epoxy groups in the molecule. Another object of the present invention is to provide a method for producing a wood-based molded article, characterized in that the ester anhydride added to the wood material is further crosslinked with bisepoxide.

Although the wood-based molded product obtained by the manufacturing method of the present invention is mainly composed of wood, it has a tough, hard, and dense surface, and has good heat resistance, abrasion resistance, and size. It has excellent stability etc. Furthermore, depending on the composition of the mixture, the wood-based molded product of the present invention surprisingly has a plasticized wood, has a dense surface, and has a shiny, plastic-like appearance.

The types of wood materials used in the present invention include wood chips, wood fibers, finely divided wood powder, etc., and there are no particular restrictions on the raw wood or tree species, such as red pine, cedar, cypress, birch, radiata pine, etc. , Lauan, etc. are used. In view of the chemicals used, these wood materials are preferably dried to a moisture content of 5 or less.

The trimellitic acid ester anhydride used in the present invention is an adduct shown in the general formula (2) obtained from trimellitic acid anhydride and glycol. Methods for synthesizing trimellitic acid ester anhydride include a direct production method from trimellitic acid anhydride and glycol, and an indirect method using an aliphatic monocarboxylic acid ester of trimellitic acid anhydride and glycol. There are no particular restrictions on the manufacturing method. In addition, there are no particular restrictions on the glycols, but they are industrially easily and inexpensively available such as ethylene glycol, propylene gelol, 1.3-jropanediol, 1.4-butanediol, and 1.5- Bentanediol, polyethylene glycol, polypropylene glycol and the like are preferred. Furthermore, the pyromellitic acid acid ester anhydride used in the present invention is obtained from pyromellitic anhydride, a 10-alkylene glycol, a polyalkylene glycol, and a polyhydric alcohol having 3 to 4 hydroxyl groups in the molecule. This is an adduct shown in the above general formula (2). The general method for synthesizing pyromellitic acid acid ester anhydride is to directly produce it from pyromellitic anhydride, glycol, and polyhydric alcohol, but the production method is not particularly limited in the present invention. The alkylene glycol or polyalkylene glycol mentioned here includes ethylene glycol, fluoropylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, and the like. Polyhydric alcohols having 3 to 4 hydroxyl groups in the molecule include glycerin, trioxyisobutane,
Examples include erythritol and pentaerythritol.

Trimellitic acid ester anhydride or pyromellitic acid acid ester anhydride has at least two acid anhydride groups in the molecule, and addition bonds occur between these and hydroxyl groups in wood materials through esterification, resulting in woody It is suitable as a crosslinking agent for products. The amount of trimellitic acid anhydride or pyromellitic acid ester anhydride used in the wood material is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of the wood material.

The bis-epoxides used in the present invention include diglycidyl ether of bisphenol A, ethylene glycol diglycidyl ether, and chryse epoxide. It is preferable to add the compound in an amount equal to or less than the equivalent amount of carboxyl group in the ring-opened ester compound.

The base materials used in the present invention include wood base materials,
Examples include plant fiber base materials other than wood base materials, inorganic base materials such as gypsum, cement, and asbestos, synthetic resin base materials, and metal base materials. The shape of the base material is mainly plate-like, but is not particularly limited. Among these, wood base materials,
For example, veneer, plywood, particle board, fiberboard, etc. are suitable. Further, it is also possible to use wood-based plate-like base materials that are in the process of being manufactured, such as fiber mats obtained by forming wood fibers spray-coated with an adhesive.

Next, the manufacturing method of the present invention will be explained step by step. First, it is preferable to dry the wood material using a vacuum dryer, a hot air dryer, etc. so that the moisture content of the wood is 5% or less. If a large amount of water remains in the wood, this water will react with the acid anhydride groups and produce polyhydric carboxylic acids as by-products, which is undesirable.

Addition of the ester anhydride to the wood material is carried out by directly incorporating the ester anhydride into the wood material. However, since ester anhydrides are generally solid at room temperature, when mixed with wood, it is preferable to mix at a temperature higher than the softening point or melting point of the ester anhydride. In some cases, the varnish 13-thyl anhydride may be dissolved in a solvent that has no reactivity to the ester anhydride, such as acetone, dioxane, tetrachloroethane, dimethylformamide, etc., and then added to the wood material. . However, in this case, it is necessary to sufficiently remove the solvent in the mixture after mixing and before hot-pressing.

Further, in some cases, it is preferable to add bisepoxide to the above mixture. Diglycidyl ether of bisphenol A is particularly preferred. There is no particular restriction on the order in which the ester anhydride and diepoxide are added to the wood material. Furthermore, it is preferable to add carbonates, oxides, and hydroxides of alkali metals or alkaline earth metals, such as calcium carbonate, calcium hydroxide, magnesium carbonate, and magnesium hydroxide, to the mixture. In this case, the above-mentioned carboxyl By forming a base metal salt, a wood-based molded product with high heat resistance can be obtained. Further, depending on the case, phenylglycide, cidyl ether, styrene oxide, epichlorohydrin, etc. may be added as a plasticizer.

Although the curing reaction in the hot press molding of the present invention proceeds satisfactorily without a catalyst, in order to further reduce the curing reaction, catalysts 14 conventionally used in acid anhydride curing, such as metal salts of carboxylic acids, tertiary amines, etc. may be added. In order to further improve the mechanical strength of the resulting wood-based molded product, glass fibers are added, and in order to impart flame retardancy, logen-containing compounds such as tetrabromobisphenol A, tetrachlorobisphenol A, and hexachlorobenzene are added. Furthermore, dyes, pigments, etc. may be added at the same time as coloring agents.

The mixture prepared as described above is further uniformly mixed using a mixer such as a blender, kneader, mixing roll, etc. Regarding the mixing conditions, as mentioned above, since ester anhydrides are generally solid at room temperature, it is preferable to mix them with the wood material at a temperature equal to or higher than the softening point or melting point of the ester anhydride. After mixing, the mixture is evenly distributed into a predetermined mold with or without pre-drying. Next, insert this mold between the hot plates of the press machine,
Heat and pressure are applied for a predetermined period of time. In addition, the above mixture is placed on a base material, a mirror plate or an embossed plate with an uneven pattern is placed on top of it, and the mixture is inserted between the hot plates of a press machine and heated and pressed for a predetermined period of time. , the wood-based molded article of the present invention is obtained. In this case, if the wood-based molded product is to have a smooth finish, the amount of spraying of the mixture placed on the base soil should be 0.3 to 2 to 1.5 Kr/m2.
is sufficient, and 1.5Kr is sufficient when engraving an uneven pattern.
It is preferable to spray a mixture of z42 or higher. As the heating temperature of the mixture heated and pressurized by the press increases, the above-mentioned reaction progresses.

In the wood-based molded article obtained by the production method of the present invention, the hydroxyl groups in the wood material are bonded to the acid anhydride groups in the ester anhydride through a ring-opening esterification reaction. Furthermore, since ester anhydride has at least two acid anhydride groups in its molecule, it exhibits excellent effects as a crosslinking agent for wood materials. In this way, the wood materials are chemically integrated with very strong bonding forces, so the wood molded products obtained by the manufacturing method of the present invention have a tough and hard surface, and have good heat resistance, abrasion resistance, and dimensions. It has excellent stability.

In addition, when the mixture is placed on a wood base material and hot-press molded, the hydroxyl groups in the wood on the surface layer of the wood base material undergo a ring-opening esterification reaction with the acid anhydride groups in the ester anhydride. Because they are bonded together, there is no need to apply an adhesive to the surface of the wood base material in the production of wood molded products.

In addition, when bis-epoxide is added to the mixture and hot-press molding is performed, the hydroxyl group in the wood material undergoes a ring-opening esterification reaction with the anhydride group in the ester anhydride, and the carboxyl group is formed at the same time. , or by an esterification reaction between the carboxyl group present in the molecule of pyromellitic acid acid ester anhydride and the epoxy group in bisepoxide, and bisepoxide further has two epoxy groups in the molecule. The ester anhydride added to the wood can be further crosslinked by bisepoxide. Therefore, the obtained wood-based molded product has a tough and hard surface.

In addition, depending on the composition of the mixture, the wood-based molded product obtained by the manufacturing method of the present invention may surprisingly have a plasticized appearance with a shiny surface and a plastic-like appearance. It exhibits the following. This material can be used as a decorative material.

In addition, the wood-based molded product obtained by the manufacturing method of the present invention can use a large amount of wood as a raw material, so it is inexpensive, lightweight, and has excellent workability.

Therefore, the wood-based molded product obtained by the production method of the present invention is suitable as an industrial component material in many fields, and is also suitable as a building material such as flooring material and wall material, and a decorative material for furniture.

Next, the present invention will be explained in more detail with reference to examples. The dried wood flour, dried chips, and dried wood fibers used in these are wooden materials that have been dried to a moisture content of 5% or less. say. It goes without saying that the present invention is not limited to the examples.

Example 1 Trimellitic acid ester anhydride with the following structural formula synthesized from trimellitic anhydride (2 mol) and ethylene glycol (1 mol) (manufactured by Shin Nippon Chemical [Recaresin TMEG]
J) 609 was added to 140 t of dry red pine wood flour that had passed through a 24-mesh sieve and mixed uniformly with a mixing roll at a roll temperature of 80 to 100°C. Thereafter, the mixture was passed through a pulverizer to form uniformly fine grains. after that,
The mixture was dried in a hot air dryer at 80° C. for about 1 hour, and then uniformly formed into a predetermined mold. Next, this mold was inserted between hot plates of a press machine and hot-press molding was performed.

The hot press molding conditions are: temperature 150'C1 pressure 5KJ/
cm" for 10 minutes, then further heated to 170'C.
Heat and pressure were applied for 60 minutes under the conditions of 1 pressure of 100 Kf/cm''. Note that deaeration was performed at the initial stage of hot pressure.

After hot-press molding, the wood-based molded product obtained was a brown plate with a thickness of 6.4 m, and had a tough and hard surface and a smooth, glossy plastic-like appearance.

Example 2 Akamatsu was passed through a 24-mesh sieve using trimellitic acid ester anhydride (New Japan Chemical Co., Ltd.'s "Recaresin TMEGJ") 49F and diglycidyl ether of bisphenol A (Mitsui Petrochemical Epoxy Co., Ltd. rEPOMIKR139J) 21 shown in Example 1. The mixture was added to dry wood powder 1301 and mixed uniformly with a mixing roll at a roll temperature of 80 to 100°C.Then, the mixture was crushed into a pulverizer to obtain uniformly fine particles.Then, the mixture was dried with hot air at 80°C. After drying in a container for about 1 hour, it was evenly formed into a predetermined mold.

Next, molding was carried out under exactly the same hot-press molding conditions as in Example 1. The obtained wood molded product was a blackish brown plate with a thickness of 6.4 wn, had a tough and hard surface, and had a smooth, glossy, plastic-like appearance.

Example 3 Trimellitic acid ester anhydride (manufactured by Shin Nippon Chemical Co., Ltd. [Rika Resin TMEGJ) 55y and calcium carbonate 15f shown in Example 1 were added to 130 dried chips of red lauan wood used as a raw material for particle board. , and mixed uniformly in a Ni-Goo with an internal temperature of 90-110°C. After that, the mixture was dried in a hot air dryer at 80°C for about 1 hour, and then
It was evenly formed into a predetermined mold. Next, molding was carried out under exactly the same hot-press molding conditions as in Example 1. The obtained wood-based molded product was a brown plate with a thickness of 6.7 cm.
The surface was tough, hard, and had a smooth appearance.

Example 4 The mixture shown in Example 1, which had been dried in a hot air dryer at 80°C for about 1 hour, was spread on the surface of lauan plywood with a thickness of 5.5 mm at a rate of 1.4 K'j'/m2. Formed evenly. Next, a mirror plate was applied to this surface, and it was inserted between the hot plates of a press to perform hot-press forming. The hot press molding conditions were as follows: When inserting, heat and press at a temperature of 150° and a pressure of 5 g/cm2 for 10 minutes, then further heat and press at a temperature of 170°C and a pressure of 80 Kfz &
Heat and pressure were applied for 50 minutes according to the conditions of 2. Note that deaeration was performed at the initial stage of hot pressure. After hot-press molding, the obtained wood-based molded product had a tough, hard, and dense surface, and had a shiny, plastic-like appearance.

Example 5 After drying the mixture in the hot air dryer at 80°C for about 1 hour as shown in Example 2, the mixture was applied to the surface of lauan plywood with a thickness of 5.5 trrm at an amount of 1.4 K? /m2 was uniformly formed. Next, a mirror plate was placed on this surface and inserted between the hot plates of a press to perform hot-press molding. The hot press molding conditions were exactly the same as in Example 4. The obtained wood-based molded product had a tough, hard and dense surface, and had a shiny plastic-like appearance.

Example 6 In a four-piece parallel flask equipped with a stirrer, condenser, thermometer, and liquid separation tube, pyromellitic anhydride 218f (1 mol), N,N-dimethylbenzylamine 22 as a catalyst, and a solvent as a solvent. Methyl ethyl ketone 2
00f and 10CH' (0.5 mol) of polyethylene glycol (molecular weight 200) was added at 90°C with stirring.
It dripped over time. After the dropwise addition was completed, stirring was continued at the same temperature for 3 hours to complete the reaction. After the reaction was completed, the temperature was reduced to 80°C under reduced pressure.
Removal of the catalyst and solvent at <RTIgt;C</RTI> afforded the product 22- as a light brown glassy solid. The acid value of this product in a non-aqueous solvent is 364 (theoretical value 353), and the acid value in a water-containing solvent is 517 (theoretical value 529), and the content of anhydride acid groups is 87%. It was found that the main component of the substance was a compound having the following structural formula.

Next, the pyromellitic acid ester anhydride 702 obtained as described above was added to 130 tons of dry wood fibers of radiata pine that had passed through a 13-mesh sieve, and mixed uniformly with a mixing roll at a roll temperature of 125 to 135°C. did. Thereafter, the mixture was milled to obtain uniformly fine particles. After that, the mixture was dried in a hot air dryer at 80℃ for about 1 hour.
After drying for a period of time, it was evenly formed into a predetermined mold.

Next, this mold was inserted between hot plates of a press machine and hot-press molding was performed. The hot-press molding conditions were as follows: At the time of insertion, the molding was heated and pressed for 10 minutes at a temperature of 170°C and a pressure of 5 KtA-, and then heated and pressed for 40 minutes at the same temperature and a pressure of 100 KW/cm. Qi is in the early stages of thermopressure.

After hot-press molding, the obtained wood-based molded product was a black plate-like product with a thickness of about 6.5 mm, had a tough and hard surface, and had a smooth, glossy, plastic-like appearance.

Example 7 Pyromellitic acid acid ester anhydride 492 prepared in Example 6 and diglycidyl ether of bisphenol A (rEPOMIKR139J manufactured by Mikata Petrochemical Epoxy ■)
21f was added to 130f of dried red lauan wood flour that had passed through a 24-mesh sieve, and mixed uniformly with a mixing roll at a roll temperature of 125 to 135°C. Then mix the mixture into 8
After drying in a hot air dryer at 0° C. for about 1 hour, it was evenly formed into a predetermined mold. Next, molding was carried out under exactly the same hot-press molding conditions as in Example 6. The obtained wood-based molded product was a blackish-brown plate with a thickness of 6.4 mm, had a tough and hard surface, and had a smooth, glossy, plastic-like appearance.

Example 8 The mixture obtained in Example 6 after being dried in a hot air dryer at 80° C. for about 1 hour was spread evenly on the surface of 12 medium-density fiberboards at a rate of 2.8 KV/m2. Formed to. Next, an embossed plate having a concavo-convex pattern was placed on the surface of the plate, and the plate was inserted between the hot plates of a press to perform hot-press molding. The hot press molding conditions were a temperature of 170°C during insertion;
After heating and pressurizing for 10 minutes at a pressure of 5 KflAm2, the pressure was further increased to 60 Kt/cm20 at the same temperature.
The mixture was heated and pressurized for a minute. Note that degassing takes place in the early stages of heat pressure. After hot-press molding, the obtained wood-based molded product had a tough, hard and dense surface, and had a three-dimensional effect and excellent cosmetic properties.

Example 9 A solvent-based polyurethane adhesive was applied to the surface of an asbestos cement board with a thickness of 6.0 mm at a coating amount of 25 r/m2, and then the solvent was evaporated using a hot air dryer. Next, on the surface of the asbestos cement board coated with the adhesive in this way, the mixture obtained in Example 7 and dried in a hot air dryer at 80°C for about 1 hour was sprayed in an amount of 1.2 Kf. /m2 was evenly formed. Next, a mirror-finished 25-plate was applied from the surface thereof, and was inserted between the hot plates of a press to perform hot-press molding. The hot press molding conditions were exactly the same as in Example 8. The obtained wood-based molded product had a tough, hard and dense surface, and had excellent cosmetic properties.

Patent applicant: Okura Industries Co., Ltd. 26-

Claims (2)

[Claims] (1) Trimethic acid ester anhydride represented by the general formula (wherein R1 represents a glycol residue), or (wherein R1 is an alkylene glycol residue, a polyalkylene glycol residue, or 3 to 4 Represents a polyhydric alcohol residue having hydroxyl groups. Represents an integer from nFii to 3.)
Pyromellitic acid acid ester anhydride having at least two anhydride groups in the molecule represented by is added to a wood material selected from wood chips, wood fibers, or wood flour, and after thoroughly mixing these, the 1. A method for producing a wood-based molded article, which comprises hot-pressing a mixture, or placing the mixture on a base material and hot-pressing the mixture. (2) Trimellitic acid ester anhydride represented by the general formula (where %R1 represents a glycol residue) or represents a polyhydric alcohol residue having 3 to 4 hydroxyl groups, n represents an integer of 1 to 3) and bis-pyromellitic acid acid ester anhydride having at least 2 anhydride groups in the molecule. Epoxide is added to a wood material selected from wood chips, wood fibers, or wood flour, and after thoroughly mixing these, the mixture is molded under hot pressure, or the mixture is placed on a base material and heated. A method for manufacturing wood-based molded products characterized by pressure molding.