JPH10180723A - Manufacture of lignocellulose molded plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adhesion to a heating board by forming the layer of an adhesive of aqueous emulsion containing an organic polyisocyanate compound, polyether, etc., the metal salt of saturated and/or unsaturated carboxylic acid of a specified number of carbon atoms on the outermost layer of a molded plate and polishing-removing the outermost layer after hot pressing. SOLUTION: A layer in which aqueous emulsion containing an organic polyisocyanate compound, polyether and/or polyester polyol, the metal salt of saturated and/or unsaturated carboxylic acid of the number of carbon atoms of 8-28 is used as an adhesive is formed only on the outermost layer of a lignocellulose molded plate, the outermost layer is polishing-removed after hot pressing. It is preferable that the number of functional groups of the polyether and/or the polyester polyol is 2-8, the content of the repeating unit -CH2 CH2 -O- of the polymers is 5-70wt.%, and 1-70 pts.wt. of the repeating unit to 100 pts.wt. of the isocyanate compound is contained in the emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hot-pressed board using lignocellulose as a main raw material. A molded article using lignocellulose as a main raw material is called a particle board when lignocellulose is wood chips, and in addition to a particle board, a wafer board using a large chip and an elongated chip (strand) are arranged in one direction. Oriented strand board (OS
B) In the case of wood fiber (fiber), it is produced as insulation board, medium specific gravity fiber board (MDF), and hard board, and is used for flooring, wall, door, sound insulation, heat insulation, tatami core, It is used as a furniture member and an automobile member.

[0002]

2. Description of the Related Art Conventionally, a fiberboard such as a particle board, a wafer board and a hard board, an MDF, and an insulation board, a rice hull board formed by molding rice hulls, a kollan board formed by molding kollan stalks, etc. As an adhesive or a binder for the production of a urea resin, a melamine resin, a urea melamine resin, a phenol melamine resin, a phenol resin or the like (hereinafter referred to as a formalin-based resin adhesive) which is thermosetting. Used. These resins are inexpensive, have excellent adhesive properties, and have characteristics of curing in a relatively short time. Formalin released from products after hot-press molding of these formalin-based resin adhesives is regarded as an environmental problem, and in actual use to reduce the amount of released formalin, the amount of free formalin in the adhesive is required. (For example, the molar ratio of formalin in the resin adhesive / the molar ratio of phenol, melamine, and urea is reduced), and a formalin catcher agent is used when the formalin-based resin adhesive is compounded. On the other hand, as an adhesive which is non-formalin-based and provides excellent board properties, use of an isocyanate-based adhesive for a board has been proposed (JP-A-57-131538, JP-A-57-1475).
No. 67, U.S. Pat. Nos. 3,557,263 and 3,636,199.
No., 3870665, 3919017, 39301
No. 10).

However, when an organic polyisocyanate-based compound (hereinafter, referred to as polyisocyanate) is used as an adhesive for lignocellulose-based materials and hot-pressed, adhesion to a hot platen due to its excellent adhesiveness. Occurs. Due to this adhesion, the molded product is damaged, the value as a product is significantly lost, and a great deal of labor is required to remove the attached material from the hot platen. In order to solve this problem, an additive to polyisocyanate has been studied in order to improve the releasability of the hot platen from metal. For example, alkyl phosphates or pyrophosphates of organic polyisocyanates (Japanese Patent Publication No. 03-018068), sulfonated compounds (Japanese Patent Publication No. 05-038309), waxes and liquid esters (Japanese Patent Publication No. 04-054390) , Aliphatic carboxylic acids (JP-A-58-36430), polysiloxane compounds (JP-A-61-86225), and fatty acid polymers (US Pat. Nos. 4,772,442 and 4,933,232).

Another method has been proposed in which a release agent is directly applied to a hot platen before hot pressing. For example,
Formation of release layer using metal soap (Japanese Patent Laid-Open No. 52-1548)
No. 75), a high-boiling polyol (German Patent No. 165317)
No. 8), use of a polysiloxane film having a functional group (British Patent No. 1359592), and coating with polytetrafluoroethylene (U.S. Pat. No. 4,347,791). However, in any of the above methods, the more the mold releasability is improved, the more the release agent, waxes, etc. are left on the board surface, so that the paint after forming the board has a large effect on the adhesion, and thus there is a problem. It is not one that can withstand the use at the manufacturing site, and at present, there is no technology that satisfies all of the process, economy, and physical properties.

[0005]

The problem to be solved by the present invention is that boards are manufactured so that they do not adhere to a hot plate even if an organic polyisocyanate-based adhesive is used. It is an object of the present invention to solve the problems of economy and physical properties and to manufacture a high-quality board with improved adhesiveness and paintability after board molding at a low cost.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found a method of manufacturing a hot-pressed board mainly made of lignocellulose using an isocyanate-based adhesive. An organic polymer which is a water emulsion composed of a polyisocyanate and a polyol, containing a metal salt of a saturated and / or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms as an internal release agent in an outermost layer that contacts a hot platen After forming a wood fiber layer coated with an isocyanate-based adhesive, hot-pressing is performed, and a hot-pressed board is manufactured by polishing and removing the outermost layer containing an internal release agent after the hot-pressing, The productivity is good because the pods formed in the hot pressing process do not adhere to the hot plate, and the water resistance derived from the organic polyisocyanate-based adhesive is improved. Since the outermost layer has been removed, including the type, adhesion of the Boards after board production, the manufacturing method of hot pressing boards having improved paintability found, and have completed the present invention.

That is, the present invention uses (1) a water emulsion containing an organic polyisocyanate compound (A) and a polyether and / or polyester polyol (B) as an adhesive for a lignocellulosic material. In the method for producing a lignocellulose molded plate, only the outermost layer of the lignocellulose molded plate has an organic polyisocyanate-based compound (A) and a polyether and / or polyester polyol (B), and has a saturated and / or
Alternatively, a layer using a water emulsion containing a metal salt of unsaturated aliphatic carboxylic acid (C) as an adhesive is formed, and after hot pressing, the outermost layer is polished and removed. Manufacturing method,

Preferably, (2) polyether and / or
Or the polyester polyol (B) has a functional group number of 2
8, wherein the repeating unit of —CH ₂ CH ₂ —O— in the structure is 5 to 70% based on the weight of the polyether and / or polyester polyol (B), and the organic polyisocyanate is contained in the aqueous emulsion. (1) the method for producing a lignocellulose molded plate according to (1), wherein the amount is 1 to 70 parts by weight with respect to 100 parts by weight of the nate-based compound (A);
(1) wherein the polyisocyanate (A) is polymethylene polyphenyl polyisocyanate.
The method for producing a lignocellulose molded plate of (4), wherein the polyether and / or polyester polyol (B) is
(1) The method for producing a lignocellulose molded plate according to the above (1), which is an amine polyol containing a nitrogen atom in a molecule; and (5) a saturated and / or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms. Metal salt of acid (C)
But octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachinic acid, lignoceric acid or behenic acid, and zinc, iron, aluminum, calcium, zirconium, magnesium, barium, (1) The method for producing a lignocellulose molded plate according to the above (1), which is at least one kind of nickel, copper, or cobalt.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The method for producing a lignocellulose molded plate (sometimes referred to as a board) according to the present invention comprises an organic polyisocyanate-based adhesive containing an organic polyisocyanate-based compound (A), a polyether and / or a polyester polyol (B). In a method for producing a lignocellulosic material using an agent, an adhesive containing a metal salt (C) of a saturated or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms is used as the organic polyisocyanate-based adhesive. This is a method for producing a lignocellulose molded plate characterized by the use of this adhesive and the treatment of hot-pressed boards. That is,
In the method of the present invention, the organic polyisocyanate-based compound (A), the polyether and / or
Or a lignocellulose layer coated with an adhesive composed of polyether polyol (B) and water as an inner layer,
A metal salt of a saturated and / or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms in the adhesive as the outermost layer (C)
To form a lignocellulose layer coated with an adhesive, followed by hot-pressing to remove the outermost layer by polishing and surface polishing to obtain a product lignocellulose molded plate.

Examples of lignocellulosic materials include strand chips, dust chips, and flake chips used for particle boards, fibers used for hard boards, MDF, and insulation boards, and agricultural products such as kollan stalks, pagasu, and rice husks. Can be These raw materials may be used alone or in combination of two or more.

The organic polyisocyanate compound (A) (hereinafter referred to as polyisocyanate (A)) may be any substance having an isocyanate group. Examples thereof include tolylene diisocyanate and 4,4. '-Diphenylmethane diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, polymethylene polyphenyl polyisocyanate (Polymeric M
DI) or a modified polyisocyanate obtained by modifying the above polyisocyanate compound with a compound having at least one active hydrogen. Among them, polymeric MDI is preferred from the viewpoint of economy.

The polyether and / or polyester polyol (B) (hereinafter referred to as polyol (B)) is a polyol having 2 to 8 functional groups and a hydroxyl value (OHv) of 24 to 800 mgKOH / g,
The repeating unit of ₂ CH ₂ —O— may be 5 to 70% with respect to the polyol (B). If it is less than 5%, the emulsifying performance is insufficient, so that it is not preferable.

As the polyether polyol, a low molecular weight compound having two or more active hydrogens as an initiator may be used in the absence of an alkylene oxide having an epoxy group in a molecule such as ethylene oxide, propylene oxide, butylene oxide or styrene oxide without a catalyst. Alternatively, it is produced by adding a catalyst using an alkali metal hydroxide, a tertiary amine or the like as a catalyst in a known manner for the production of a polyol. Initiators include glycerin, sucrose, pentaerythritol, sorbitol, trimethylolpropane, diglycerin, propylene glycol,
Alcohols such as dipropylene glycol, diethylene glycol, ethylene glycol, 1,4-butanediol, and 1,2-butanediol; phenols such as hydroquinone, bisphenol A and novolak; and ethanol such as monoethanolamine, diethanolamine and triethanolamine. Amines, ethylenediamine, diethylenetriamine, orthotolylenediamine, metatolylenediamine, 4,4′-diphenylmethanediamine,
Examples thereof include amines such as 2,4'-diphenylmethanediamine and polymethylpolyphenylpolyamine, and these may be used alone or as a mixture. Preferably, the initiator is an amine polyol containing a nitrogen atom in the molecule of the amines.

The polyester polyol is obtained by an addition reaction between a carboxylic anhydride and an alcohol, a polycondensation reaction between a polycarboxylic acid and an alcohol, and addition of an alkylene oxide to an acid. As carboxylic anhydrides, for example, maleic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, itaconic anhydride, phthalic anhydride, glutaric anhydride, glutaconic anhydride, diglycolic anhydride, citraconic anhydride , Diphenic anhydride, toluic anhydride and the like, and as the polycarboxylic acid, for example, maleic acid, terephthalic acid, dimethyl terephthalic acid, isophthalic acid, fumaric acid, oxalic acid,
Malonic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, citric acid, trimellitic acid and the like. Also, as alcohol,
The alcohols and phenols mentioned as the above-mentioned initiators, or alkylene oxide adducts of the above-mentioned initiators can be used.

The metal salt of a saturated and / or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms (C) (hereinafter referred to as a metal salt of a carboxylic acid (C)) is a monocarboxylic acid. , Di and tri can be used. For example, aliphatic carboxylic acids such as octylic acid, lauric acid, mystyric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachiic acid, lignoceric acid, and behenic acid are exemplified. Examples of the metal component include zinc, iron, aluminum, calcium, zirconium, magnesium, barium, nickel, copper, and cobalt. These are acid components,
At least one selected from the respective groups of metal components can be used in combination. That is, a metal salt of a carboxylic acid composed of an acid component selected from the group consisting of the above preferred carboxylic acids and a metal component selected from the group consisting of the above preferred metals can be used alone or as a mixture of two or more kinds.

According to the production method of the present invention, an adhesive which is a water emulsion containing the polyisocyanate (A), the polyol (B) and water, the polyisocyanate (A), the polyol (B) and the water And an adhesive which is a water emulsion containing a metal salt of a carboxylic acid (C). The metal salt of a carboxylic acid (C) may be added to an adhesive which is a water emulsion containing the polyisocyanate (A), the polyol (B) and water, or may be previously prepared, preferably as a water emulsion. May be added at any time when the lignocellulosic material and the adhesive are mixed. In these adhesives, the mixing ratio of the polyisocyanate (A) and the polyol (B) is (A) :( B) = 100:
It is in the range of 1 to 100: 70, preferably 100: 5.
~ 100: 50. That is, the polyol (B) is used in an amount of 1 to 70 parts by weight based on 100 parts by weight of the polyisocyanate (A). If the polyol (B) is less than 1 part by weight, a stable water emulsion will not be obtained,
On the other hand, if it exceeds 70 parts by weight, the physical properties of the board deteriorate. The method for preparing the water emulsion containing the polyisocyanate (A), the polyol (B) and water is not particularly limited, and various methods and methods may be used as long as the mixture is emulsified under shear stress. Applicable. For example, the polyisocyanate (A), the polyol (B), and water may be simultaneously mixed and emulsified by high-speed mixing of three types, or the polyisocyanate (A) may be displaced in a mixture of the polyol and water to reduce the stress. It may be added and emulsified while adding, or may be added to water and emulsified while adding shear stress after mixing the polyol (B) and the polyisocyanate (A). The mixing system may be a batch system or a continuous system, and a homogenizer, a static mixer or the like can be used.

A water emulsion containing the polyisocyanate (A) and the polyol (B), which are other adhesives, and further containing a metal salt of a carboxylic acid (C) is obtained by suspending or emulsifying these components in water. If so, there is no particular limitation. For example,
A solution obtained by adding a metal salt of a carboxylic acid (C) to a water emulsion containing the polyisocyanate (A), the polyol (B) and water obtained by the above method and suspending or emulsifying the emulsion;
Preparing a water emulsion of a metal salt of a carboxylic acid (C),
This is mixed with a polyisocyanate (A), a polyol (B) and water and stirred, or a polyisocyanate (A)
And a mixture of water and a polyol (B) with water, or separately added to a water emulsion of a metal salt of a carboxylic acid (C) and mixed and stirred.

For example, a method in which four kinds of polyisocyanate (A), polyol (B), metal salt of carboxylic acid (C) and water are simultaneously mixed and emulsified at the same time, emulsification is carried out. After the dispersion, the polyol (B) is added and dissolved, and the polyisocyanate is mixed at a high speed to emulsify the mixture. The polyol (B) is mixed with the metal salt (C) of carboxylic acid and water, and then the polyisocyanate (A) is mixed. And emulsification by adding polyol (B), polyisocyanate (A), and metal salt of carboxylic acid (C) into water while stirring at high speed, After dissolving the polyol (B) in water, emulsifying the polyisocyanate (A) while mixing the polyisocyanate (A) at a high speed, various methods such as emulsification by adding a metal salt of a carboxylic acid (C) can be applied. The amount of water used depends on the amount of water in the lignocellulosic material, but it is sufficient that the adhesive can be uniformly mixed with the lignocellulosic material. Therefore, 1 to 300% by weight of the amount of the adhesive is preferable.

The metal salt (C) of the carboxylic acid may be present in the composition in the form thereof. The metal salt (C) may be added in the form of a metal salt or may be added separately from the aliphatic carboxylic acid and the metal compound. May be used. Further, the metal salt (C) of the carboxylic acid may be used as a water emulsion using an emulsifier, if necessary. As the emulsifier in this case, those generally used may be used, and fatty acid soap, rosin acid soap,
Anionic surfactants such as alkyl sulfonates, alkyl benzene sulfonates, dialkyl aryl sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryl sulfonates, polyoxyethylene alkyl ethers, Examples of the surfactant include surfactants such as polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan fatty acid ester, and oxyethylene oxypropylene block copolymer, but the present invention is not limited to these surfactants. These surfactants may be used alone or in combination of two or more.

Further, a stabilizer may be used if necessary. The stabilizer in this case may be any as long as it can stabilize the metal salt of carboxylic acid (C) and an emulsion thereof, such as a natural polymer compound or a synthetic polymer compound which forms a protective colloid. Can be used, for example,
Gelatin, gum arabic, carboxymethyl cellulose, polyvinyl alcohol and the like can be used.

In the method of the present invention, each of the above adhesive components is used for producing a lignocellulose molded plate.
An aqueous emulsion containing a polyisocyanate (A) and a polyol (B) and an aqueous emulsion of a metal salt of a carboxylic acid (C) are separately mixed with a lignocellulosic material, and the mixture is stirred uniformly. It may be an aspect.

In the production of the lignocellulose molded plate of the present invention, the outermost layer in which the molded plate contacts the hot platen of the molding machine includes:
The above polyisocyanate-based adhesive containing the metal salt of carboxylic acid (C) is used, and the above-mentioned polyisocyanate that does not contain the metal salt of carboxylic acid (C) is formed in the inner layer where the molded plate does not contact the hot plate of the molding machine. A nat-based adhesive is used. In any of the layers, the ratio of the adhesive to the lignocellulose was such that the weight ratio of the active ingredient of the polyisocyanate (A) and the polyol (B) to the lignocellulose material in the adhesive was 2: 1.
00: 30: 100, preferably 3:10.
The range is 0 to 20: 100. If the amount of the active ingredient is less than 2 parts by weight with respect to 100 parts by weight of the lignocellulosic material, the effect as an adhesive cannot be obtained, and if the amount is 30 parts by weight, sufficient board properties can be obtained. Use of the agent is industrially useless. The method for mixing the lignocellulosic material and the water emulsion as the adhesive of the present invention is to spray the water emulsion on the lignocellulose material in a blender or to use a similar device to add water to the lignocellulose material. It is desirable to mix the emulsion uniformly. At this time, if necessary, it may be used by diluting with a solvent or water. In this case, it is economical to dilute with water,
It is preferable from the viewpoint of safety.

For forming, a lignocellulose layer containing an isocyanate-based adhesive having improved releasability containing a metal salt of carboxylic acid (C) may be formed as the outermost layer, and a metal salt of carboxylic acid may be formed as an inner layer. A lignocellulose layer containing an isocyanate-based adhesive containing no (C).
This layer may be a single layer or a multilayer. If necessary, pre-pressing may be performed after lamination, or a pre-pressed mat may be laminated before lamination. The formation of a lignocellulose layer containing an isocyanate-based adhesive with improved releasability as the outermost layer may be formed at the time of forming, for example, an isocyanate-based adhesive with improved releasability on the lower surface of a hot platen. After forming a lignocellulose layer using an agent, a lignocellulose layer using an isocyanate-based adhesive containing no metal salt of carboxylic acid (C) was placed on the top, and the releasability was further improved thereon. A lignocellulose layer using an isocyanate-based adhesive may be formed.

The ratio of the outermost layer (the lignocellulose layer coated with an adhesive having improved release properties) to the inner layer (the lignocellulose layer coated with an adhesive whose release properties are not improved) is as follows:
Since the outermost layer is polished and removed after hot pressing, the outermost layer is formed at a forming ratio (weight conversion) so that the outermost layer can be spread without gaps on the board surface or formed mat:
The inner layer is preferably in the range of 0.1: 100 to 30: 100. If the amount is less than this, lignocellulose coated with an adhesive whose releasability has not been improved appears on the surface of the mat during forming, and the releasability is undesirably reduced.

The mixture of the adhesive and the lignocellulosic material is subjected to hot-pressing after forming, and can be formed from a single layer to a plurality of layers at the time of forming. After the forming, pre-pressing may be performed before hot-pressing. The hot press may be a flat plate or a curved shape, since the heat only needs to be transmitted to the molding material, but a flat plate press is preferable in terms of continuous productivity and cost. Further, the press may be a continuous press or a multi-stage press. The board after the hot pressing may be finished by removing the layer containing the adhesive having improved the releasability of the outermost layer and polishing it to a desired thickness if necessary. Further, the removed lignocellulose layer can be used as a raw material lignocellulose material after being sufficiently loosened. Further, in the present invention, an antioxidant, an ultraviolet absorber, a plasticizer, a surfactant, a silane coupling agent, a poval, a metal catalyst, an internal mold release agent, an external mold release agent, and a synthetic agent as long as a desired effect is not impaired. A rubber latex and an acrylic emulsion may be used in combination.

[0026]

The present invention will be described in more detail with reference to the following examples. However, these examples do not limit the present invention in any way. Tables 1 and 2 show the evaluation results in Examples and Comparative Examples. In the examples, parts and ratios are by weight unless otherwise specified. The common manufacturing conditions of the boards in the performance comparison are described below. Raw material: dust chips or wood fiber (water content 7.
0%) Board composition: Single layer or three layers Board thickness (excluding polished part): 10 mm (1 when outer layer polishing)
2 mm) Matt water content: 16% Hot pressing temperature: 180 ° C Pressing pressure: 35 kg / cm ² Pressing time: 130 seconds Setting density: 700 kg / m ³

Evaluation Test 1. Flexural strength A specimen was cut from a molded sample to a width of 50 mm and a length of 275 mm (span of 225 mm) in accordance with the test piece of “Fibreboard JIS-A-5905”, and a flexural strength test was performed. The results were expressed as normal bending strength. 2. Flexural strength when wet (A test) The test piece was cut in the same manner as described above. Next, the test piece was immersed in warm water of 70 ± 3 ° C. for 2 hours, immersed in normal temperature water for 1 hour, and then subjected to a bending strength test in a wet state. The results were expressed as wet A flexural strength. 3. Core peel strength A test piece was cut from a molded sample to a width of 50 mm and a length of 50 mm in accordance with the item of the test piece of “Fibreboard JIS-A-5905”, and a peel test was performed. The results were expressed as core peel strength. 4. Releasability Test At the time of hot pressing, a steel-made coal board was used, and the state of attachment of the chip to the cold board after hot pressing was visually confirmed. Perform this operation up to 30
The number of repetitions until the adhesion was confirmed was recorded.

Example 1 First, with the composition shown in Table 1, ethylenediamine was used as an initiator,
Propylene oxide / ethylene oxide block copolymer PPG
(Ethylene oxide content: 40% based on the total amount of PPG; hydroxyl value: 452 mg KOH / g) 17.6 parts were dissolved in 94.2 parts of water, and further, polymeric MDI (manufactured by Mitsui Toatsu Chemicals, Inc .; trade name Cosmonate) M-200) 56.2
The mixture was added and emulsified while stirring at a high speed to obtain an adhesive composition for a core layer. In the same manner, after emulsifying the adhesive composition for the core layer, an aqueous emulsified solution of zinc stearate (solid content: 31%) as an internal release agent was reduced to 2% based on the solid content of the adhesive composition. And the mixture was stirred uniformly to obtain an adhesive composition for a surface layer. The obtained adhesive composition was excellent in emulsified state and viscosity both for the surface layer and the core layer. Immediately forming the core layer adhesive into 1054 parts of wood fiber which is a lignocellulosic material in the blender. Was spray-coated using a spray gun so as to be 8/6/8% of the above. In addition, the surface adhesive was immediately applied to the wood fiber 2 which is a lignocellulosic material in a blender.
Spraying was applied to 11 parts using a spray gun so that the solid content of the adhesive was 7% of the absolutely dry wood. Surface layer / core layer 1 / core layer 2 / core layer 1 / 30cm square on steel coal
Forming was performed uniformly so that the surface layer = 1 / 2.5 / 5 / 2.5 / 1, and a steel coiler was covered, and hot-pressed under the above conditions. After hot pressing, adhesion to the steel coal board was observed, but no adhesion was observed. The board surface after hot pressing was polished by 1 mm for each of the upper and lower sides to obtain a board. The obtained board was used for physical property comparison, and the above operation was repeated using the same coal board again. No adhesion to the steel coal board was observed even after repeating 50 times. When an aqueous emulsion paint having a thickness of 10 μm was applied to the obtained board, it could be applied uniformly and dried to obtain a good coating.

Example 2 The procedure was carried out except that the lignocellulosic material used was changed to dust chips, and an emulsion of zinc stearate was added so as to be 10% of the solid content of the adhesive composition. The same operation as in Example 1 was performed. Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed. The coating condition was also good.

Example 3 The same operation as in Example 1 was carried out except that the used zinc stearate was added in a powder form after emulsifying the polyisocyanate. Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed. The coating condition was also good.

Example 4 Example 1 was repeated except that the initiator of the polyol used was changed to triethanolamine (TEOA) (ethylene oxide content: 50%; hydroxyl value: 251 mg KOH / g), and the number of used parts was changed to 14.1 parts. The same operation was performed. Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed.
The coating condition was also good.

Example 5 The same operation as in Example 1 was carried out except that the initiator of the polyol used was changed to orthotoluenediamine (OTD) (ethylene oxide content: 55%; hydroxyl value: 248 mgKOH / g). Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed. The coating condition was also good.

Example 6 The same operation as in Example 1 was carried out except that the polyol used was a mixture of 7.0 parts of the polyol used in Example 1 and 3.5 parts of the polyol used in Example 5. . Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed. The coating condition was also good.

Example 7 The same operation as in Example 1 was carried out except that a polyester polyol synthesized by esterifying the polyol used from 17.4 parts of the polyol used in Example 1 and 2.5 parts of phthalic anhydride was used. went. Even after the operation was repeated 50 times, no adhesion to the steel coal board was observed. The coating condition was also good.

Comparative Examples 1 to 7 Boards were formed using wood fibers in the same manner as in Examples 1 to 7 except that the outermost layer was polished by 0.1 mm after hot-pressing the boards. No adhesion to the steel coal board was observed even after the operation was repeated 50 times. However, when the coating was performed in the same manner as in Example 1, the coating repelled the paint in the coating process and the drying process, resulting in a mottled painted surface. .

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

As is apparent from the above description, according to the method of the present invention, the adhesion to the hot plate, which is practically unavoidable in the board manufacturing process using the conventional isocyanate-based adhesive, is also eliminated. , Increased system productivity,
Further, the board obtained by molding has good paintability and good physical properties. Accordingly, the method of the present invention is suitable as an industrial method for producing a low-cost lignocellulose molded plate with excellent processability and good quality at a high productivity.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Taku Nago 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Mitsui Toatsu Chemicals Co., Ltd.

Claims (5)

[Claims] 1. Organic polyisocyanate compound (A)
A method for producing a lignocellulose molded plate using a water emulsion containing a polyether and / or a polyester polyol (B) as an adhesive for a lignocellulosic material, wherein only the outermost layer of the lignocellulose molded plate is an organic polyisocyanate System compound (A) and polyether and / or polyester polyol (B), having 8 carbon atoms
Forming a layer using a water emulsion containing a metal salt (C) of a saturated and / or unsaturated aliphatic carboxylic acid having a pH of from 28 to 28 as an adhesive, and polishing and removing the outermost layer after hot pressing. For producing a lignocellulose molded plate. 2. The polyether and / or polyester polyol (B) has 2 to 8 functional groups, and the repeating unit of —CH ₂ CH ₂ —O— in the structure is polyether and / or polyester polyol (B). ), And 1 to 100 parts by weight of the organic polyisocyanate compound (A) in the aqueous emulsion.
The method for producing a lignocellulose molded plate according to claim 1, wherein the amount is from 70 to 70 parts by weight. 3. Organic polyisocyanate compound (A)
Is a polymethylene polyphenyl polyisocyanate, The method for producing a lignocellulose molded plate according to claim 1, wherein 4. The process for producing a lignocellulose molded plate according to claim 1, wherein the polyether and / or polyester polyol (B) is an amine polyol containing a nitrogen atom in the molecule. 5. The metal salt (C) of a saturated and / or unsaturated aliphatic carboxylic acid having 8 to 28 carbon atoms is octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid. , Linolenic acid, arachinic acid, lignoceric acid or behenic acid, and zinc,
2. The material according to claim 1, wherein the material is at least one of iron, aluminum, calcium, zirconium, magnesium, barium, nickel, copper and cobalt.
The method for producing a lignocellulose molded plate according to the above.