JP2006089676A - Adhesive for woody material, woody board, and method for producing the woody board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive for a woody material, capable of improving productivity of the woody board, to provide the woody board given by using the adhesive for the woody material, and to provide a method for producing the woody board. <P>SOLUTION: This adhesive for the woody material contains a water-soluble thermosetting resin and a surfactant, wherein the thermosetting resin preferably comprises a melamine resin or a urea melamine resin and the surfactant preferably comprises a nonionic surfactant or an anionic surfactant. The woody board is obtained by using the adhesive for the woody material. The method for producing the woody board comprises using the adhesive for the woody material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wood material adhesive capable of improving the productivity of a wood board, a wood board using the wood material adhesive, and a wood board manufacturing method.

  Examples of the wood material conventionally used in the construction field and the like include plywood and wood board. The plywood is obtained by, for example, a method in which an adhesive is applied to a single plate, a predetermined number of sheets are stacked, sandwiched between molding plates and temporarily bonded by cold pressure, and then the adhesive is cured by hot pressure. The wood board can be obtained by, for example, a method of spraying an adhesive with a wood chip, molding it into a mat shape, sandwiching the wood board, and then curing the adhesive by hot pressure. Examples of the wood material adhesive used in the production of these wood materials include a mixture of a water-soluble thermosetting resin such as a resol type phenol resin and a curing accelerator, a viscosity adjusting agent, a filler, etc., if necessary. Can be used (see, for example, Patent Document 1).

However, the adhesive for wood material disclosed in Patent Document 1 does not have sufficient curability of the adhesive, and the adhesive for wood material from the surface of the veneer or the wood chip before the adhesive is cured during hot pressing. Ooze out, and the oozed adhesive for wood material adheres the plywood surface or wood board surface to the molded board after hot pressing. In order to peel the plywood or wood board from the molded board, it is necessary to slowly release the pressure after hot pressing so that the single boards or wood chips are not peeled off, which is a factor of lowering productivity. In particular, wood materials adhesives that use resins obtained by reducing the reaction ratio of formaldehydes to urea, melamine, and phenols, which correspond to health problems represented by sick house syndrome, and wood materials to which formaldehyde absorbents are added. The material adhesive has sufficient practical strength as a wood board, but is inferior in adhesive strength and curability to the previous adhesive. Therefore, when using an adhesive corresponding to a health problem, it is necessary to further slowly release the pressure after hot pressing, which causes a further decrease in productivity.

JP 2001-131521 A

  An object of the present invention is to provide a wood material adhesive having good productivity, a wood board using the wood material adhesive, and a method for producing the wood board.

  As a result of intensive studies to solve the above problems, the present inventors have found that when a wood material is produced using an adhesive containing a surfactant, the surfactant bleeds to the surface of the adhesive layer, and this bleed surface activity The agent acts as a mold release agent between the wood material and the molded board, and it is not necessary to slowly release the pressure to separate the wood material from the molded board, resulting in good productivity and sufficient adhesive strength As a result, the present invention has been completed.

  That is, the present invention provides an adhesive for a wood material, which contains an aqueous solution of a water-soluble thermosetting resin and a surfactant.

  The present invention also provides a wood board, which is obtained using the wood material adhesive.

  Furthermore, this invention provides the manufacturing method of the wooden board characterized by using the said adhesive agent for wooden materials.

  By using the wood material adhesive disclosed in the present invention, it is not necessary to slowly release the pressure for separating the wood material and the molded plate, which greatly contributes to improving the productivity of the wood material. Further, the adhesive for a wood material according to the present invention improves the peelability between the wood material and the molded plate, and therefore requires less force to separate. Therefore, although the strength of wooden boards and plywood has reached a practical level, the reaction between formaldehydes and urea, melamine, and phenols, which are difficult to use because they require a large force when pulled away from the molded board during production Wood boards and plywood can be used even with wood material adhesives that address health problems such as wood material adhesives using resins obtained by reducing the ratio and wood material adhesives with formaldehyde absorbent added. It can be manufactured efficiently.

  Examples of the aqueous solution of the water-soluble thermosetting resin used in the present invention include an aqueous solution of a resol type phenol resin, an aqueous solution of a melamine resin, an aqueous solution of a urea melamine resin, an aqueous solution of a urea resin, and the like. Examples of the aqueous solutions of these resins include aqueous solutions of resins obtained by reacting one or more compounds selected from the group consisting of phenol, melamine, and urea with formaldehyde.

  Examples of the aqueous solution of the resol type phenol resin include an aqueous solution of a resin obtained by reacting phenols with formaldehyde in the presence of an alkali catalyst. Examples of the aqueous solution of the melamine resin include an aqueous solution of a resin obtained by reacting melamine and formaldehyde in the presence of an alkali catalyst and further reacting in the presence of an acid catalyst as necessary. Examples of the aqueous solution of urea melamine resin include an aqueous solution of a resin obtained by reacting urea, melamine, and formaldehyde in the presence of an alkali catalyst, and further reacting in the presence of an acid catalyst as necessary. Examples of the urea resin aqueous solution include an aqueous resin solution obtained by reacting urea and formaldehyde in the presence of an alkali catalyst and further reacting in the presence of an acid catalyst as necessary. The aqueous solution of these resins is preferably an aqueous solution of a resin having a nonvolatile content of 40 to 80% by weight.

  Examples of the phenols used in the production of the aqueous solution of the resole-type phenol resin include phenol, cresol, bisphenols, resorcinol, and the like.

  Examples of the formaldehydes include an aqueous formaldehyde solution, paraformaldehyde, and glyoxal.

  Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, ammonia, hexamethylenetetramine and the like. Examples of the acid catalyst include formic acid, acetic acid, and oxalic acid.

  When preparing the aqueous solution of the resol type phenol resin, the reaction ratio [(F) / (P)] of phenols (P) and formaldehyde (F) is small in the amount of formaldehyde released from the obtained plywood, From the viewpoint of improving the production environment and the environment when using the plywood, the molar ratio is preferably 1.0 to 3.5, and particularly preferably 1.5 to 2.5.

  When adjusting the aqueous solution of the melamine resin, the reaction ratio [(F) / (M)] of melamine (M) and formaldehyde (F) is low in the amount of formaldehyde released from the resulting plywood. The molar ratio is preferably 0.5 to 2.5 from the viewpoint that the environment during use is good.

  When adjusting the aqueous solution of urea melamine resin, the reaction ratio “(F) / [(M) + (U)]” of melamine (M), urea (U) and formaldehyde (F) is obtained from the obtained plywood. From the point that the amount of formaldehyde released is small and the production environment and the environment when using plywood are good, the molar ratio is preferably 0.5 to 2.5.

  When adjusting the urea resin aqueous solution, the reaction ratio [(F) / (U)] of urea (U) and formaldehyde (F) is low in the amount of formaldehyde released from the resulting plywood. The molar ratio is preferably 0.5 to 2.5 from the viewpoint that the environment during use is good.

  As the aqueous solution of the water-soluble thermoplastic resin, an aqueous solution of a melamine resin or an aqueous solution of a urea melamine resin can be more preferably used. Moreover, the aqueous solution of a water-soluble thermoplastic resin may be used independently and may use 2 or more types together.

  Examples of the surfactant used in the present invention include an anionic surfactant, a cationic surfactant, and a nonionic surfactant. Examples of the anionic surfactant include fatty acid salts; sulfate esters such as polyoxyethylene alkyl sulfates and polyoxyethylene alkyl allyl sulfates; phosphorus such as alkyl phosphates and polyoxyethylene alkyl ether phosphates. Acid ester salts; alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, sulfonic acid ester salts such as naphthalene sulfonic acid formalin condensate, and the like. In addition, special polycarboxylic acid type polymer surfactants, fluorine surfactants and the like can also be mentioned as anionic surfactants.

  Examples of the cationic surfactant include aliphatic amine salts, quaternary ammonium salts, alkylpyridinium salts, and the like.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, alkylsulfinyl alcohols, fatty acid monoglycerides and the like. Is mentioned.

  The surfactant used in the present invention is preferably a nonionic surfactant and / or an anionic surfactant. Among nonionic surfactants, polyoxyethylene alkyl ethers are preferable. Of the anionic surfactants, sulfate ester salts or phosphate ester salts are preferred.

  The surfactant used in the present invention can be used, for example, in a liquid form or a powder form. However, it is preferable to use a liquid form in order to uniformly dissolve and disperse the adhesive in the wood material. In this case, as the solution for dissolving the surfactant, an organic solvent or water can be used, but water is preferable in consideration of the risk of fire and the health hazard of the volatile organic solvent. The amount of the active ingredient of the surfactant in the liquid is not particularly limited, but may be appropriately diluted in consideration of workability, and the amount of the active ingredient is preferably 1 to 40% by weight.

  The amount of the surfactant used is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the solid content of the synthetic resin because the release effect is effectively expressed and the deterioration of the adhesive performance is small. 0.02-1 weight part is more preferable with respect to 100 weight part of solid content. Moreover, surfactant may be used independently and may use 2 or more types together.

  The adhesive for woody material of the present invention can be produced, for example, by mixing an aqueous solution of the water-soluble thermoplastic resin and the surfactant. At this time, a curing accelerator, a filler, a viscosity modifier, a formamide scavenger and the like can be added as necessary.

  As the curing agent, for example, as a curing accelerator that can be used when using an aqueous solution of the resol type phenol resin as an aqueous solution of a water-soluble thermoplastic resin, for example, sodium carbonate, sodium bicarbonate and the like can be mentioned, Examples of the curing accelerator that can be used when using the aqueous solution of the melamine resin, the aqueous solution of the urea resin, and the aqueous solution of the urea melamine resin as the aqueous solution of the resin include, for example, ammonium chloride, ammonium sulfate, oxalic acid, citric acid, hydrochloric acid, sulfuric acid Etc. The amount of the curing agent used when the aqueous solution of the melamine resin, the aqueous solution of the urea resin, or the aqueous solution of the urea melamine resin is used as the aqueous solution of the water-soluble thermoplastic resin is 0. 5 to 5 parts by weight is preferred.

  Examples of the filler that can be used when using the aqueous solution of the resol type phenol resin as the aqueous solution of the water-soluble thermoplastic resin include wheat flour and calcium carbonate. Examples of the filler that can be used when the melamine resin, urea resin, or urea melamine resin is used as the aqueous solution of the water-soluble thermoplastic resin include wheat flour, rice flour, walnut flour, and wood flour. The amount of the filler used when using the aqueous solution of the melamine resin, the aqueous solution of the urea resin, and the aqueous solution of the urea melamine resin as the aqueous solution of the water-soluble thermoplastic resin is 5 to 50 parts by weight with respect to 100 parts by weight of the resin solid content. Is preferred.

  Examples of the viscosity modifier include water.

  Examples of the formamide absorbent include polyamide compounds, urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, and amidine compounds.

  The wood board of the present invention is obtained using the wood material adhesive of the present invention. Specifically, for example, the wood material adhesive of the present invention is applied to a wood substrate such as a chip, wafer, or fiber by spraying, or the wood material adhesive of the present invention is added to a wood substrate. , Mixed, and then molded into a mat shape, then hot-press molded at 130 to 230 ° C., and then decompressed for production. Here, the wood board referred to in the present invention means a wood board such as a particle board, an OSB (Oriented Strand Board) or an MDF (Medium Density Fiber Board) composed of the wood base material.

  Hereinafter, the present invention will be described with reference to examples and comparative examples. In the examples, parts and% are based on weight unless otherwise specified.

Production Example 1 (Preparation of aqueous solution of urea melamine resin)
Stirring was started by putting 1000 grams of 40% aqueous formaldehyde solution into a flask equipped with a reflux apparatus. After adjusting the pH to 8 with a 50% aqueous sodium hydroxide solution, 400 grams of urea was added and the temperature was raised to 85 ° C. The pH was adjusted to 5 with 20% formic acid and the temperature was raised to 90 ° C. After reacting at 90 ° C. for 3 hours, the pH was adjusted to 7 with a 50% aqueous sodium hydroxide solution. Thereafter, 29 grams of melamine was added and reacted for 10 minutes, and 455 grams of urea was further added to lower the temperature to 60 ° C. After reacting at 60 ° C. for 30 minutes, 238 grams of water was removed by distillation under reduced pressure, and further cooled to room temperature to prepare an aqueous solution of urea melamine resin.

Example 1
Nonionic surfactant Neugen NL-30 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 100%] as a mold release agent in 100 parts of an aqueous solution of urea melamine resin obtained in Production Example 1 as a curing agent 2 parts of ammonium chloride and 8 parts of paraffin wax emulsion [Diaproof WY-4, solid content 45%, Dainippon Color Co., Ltd.] as a water repellent were mixed to obtain an adhesive for woody material of the present invention. The wood material adhesive is 12% in solid content ratio and 8% in the core layer chip (water content 3%) with respect to the surface layer chip (water content 4%) processed from the South Sea wood for particle board. Were added and mixed. Half of the adhesive-mixed surface chip was sprayed on a molded plate with a 30 cm square wooden frame, then the adhesive-mixed core chip was sprayed, and finally the remaining adhesive-mixed surface chip was sprayed. . In this case, the ratio of chip usage before mixing the adhesive (chip ratio) was 45% for the surface layer and 55% for the core layer. Here, a stainless plate (SUS304) whose surface was polished with # 800 was used as the molding plate. A 15 mm spacer was sandwiched between the molded plates, and a particle board was molded by hot pressing with a hot platen at 160 ° C. and 3.0 MPa for 380 seconds. After decompression, the adhesion of the particle board to the molded plate was visually observed and evaluated. The evaluation criteria are shown below.
○: Although there is some adhesion, the particle board can be easily peeled off from the molded plate, and the particle board surface after peeling off from the molded plate is also clean.
X: The amount of adhesion is large, and it is difficult to peel off the particle board from the molded plate. Roughness can be confirmed on the surface of the particle board after peeling off from the molded plate.

  Evaluation of strength performance and formaldehyde emission of the obtained particle board was performed. The strength performance evaluation of the particle board was performed according to Japanese Industrial Standard A-5908 “Particle Board”. Evaluation of formaldehyde emission amount is in accordance with Japanese Industrial Standard A-1460 “Testing method of formaldehyde emission amount of building boards-desiccator method”. After 1 day of molding, it is used as a test piece for formaldehyde measurement. Formaldehyde emission was measured after curing for 7 days at room temperature. The obtained results are shown in Table 1.

Example 2
The same method as in Example 1 except that 0.2 parts of anionic surfactant Emar 2F-30 [manufactured by Kao Corporation; active ingredient 30%] was used instead of 0.05 parts of Neugen NL-30. The particle board was molded and evaluated. The obtained results are shown in Table 1.

Comparative Example 1
A particle board was molded and evaluated in the same manner as in Example 1 except that 0.05 part of Neugen NL-30 was not used. The obtained results are shown in Table 1.

Claims (7)

An adhesive for woody material, comprising an aqueous solution of a water-soluble thermosetting resin and a surfactant. The adhesive for woody materials according to claim 1, wherein the aqueous solution of the water-soluble thermosetting resin is an aqueous solution of a melamine resin or an aqueous solution of a urea melamine resin. The adhesive for woody materials according to claim 2, wherein the surfactant is a nonionic surfactant and / or an anionic surfactant. 4. The adhesive for woody material according to claim 3, wherein the nonionic surfactant is a polyoxyethylene alkyl ether and the anionic surfactant is a sulfate ester salt or a phosphate ester salt. The adhesive for woody materials according to any one of claims 1 to 4, wherein the amount of the surfactant used is 0.01 to 5 parts with respect to 100 parts by weight of the solid content of the synthetic resin. A wood board obtained by using the adhesive for wood material according to any one of claims 1 to 5. A method for producing a wood board, wherein the wood material adhesive according to any one of claims 1 to 5 is used.