JP4021182B2 - Wood material surface repair agent - Google Patents

Description

【００５８】
表１から、実施例１〜６の各補修剤によれば、２５℃における固化速度（樹脂層全体が固化するまでの時間）がいずれも６５秒以内と速い上、軟化点１４５℃のテルペンフェノール樹脂を添加した実施例５では４３秒、軟化点１２５℃のロジンエステル樹脂を添加した実施例６では４４秒と、前記テルペンフェノール樹脂またはロジンエステル樹脂を添加しない場合よりもさらに速いことが明らかである。また、実施例１〜６の各補修剤は、木質材料表面の補修剤に求められる諸性能にも優れていることが明らかである。
【００５９】
前記各実施例に対し、比較例１の２液硬化型ウレタン系樹脂からなる補修剤は樹脂のロスが大であり、比較例２の１液硬化型ウレタン系樹脂からなる補修剤は樹脂のロスは比較的少ないものの、２５℃における固化速度が３００秒以上であって樹脂層全体が固化するまでに実施例１〜６の各補修剤よりもはるかに長い時間を要することが明らかである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a repair agent that fills recesses such as cracks, grooves, wormholes, and knots on the surface of woody materials such as wood, plywood, laminated wood, and veneer laminate (LVL) to close the recesses. .
[0002]
[Prior art]
The surface of the woody material such as wood, plywood, laminated wood, or single board laminated material (LVL) generally has recesses such as cracks, grooves, worm-eaten holes, node holes, etc. The product value of is reduced. Therefore, conventionally, a repairing agent containing latex, urethane resin, epoxy resin or the like is known in order to fill the recess and close the recess.
[0003]
Since the conventional repair agent is made of a two-component curable resin, the main agent and the curing agent must be mixed at the time of use, and there is a problem that handling is complicated. Further, since the two-component curable resin cures immediately when the main agent and the curing agent are mixed, for example, when the two-component curable resin is filled in the recess from a nozzle or the like, the resin cured in the nozzle is There is also a problem that the loss of the resin must be discarded and the loss of the resin becomes large.
[0004]
If a one-component curable urethane resin or the like is used instead of the two-component curable resin, it is easy to handle because the labor of mixing can be saved. The one-component curable resin is compared with the two-component curable resin. Since the time required for curing is long, resin loss can be reduced.
[0005]
However, since the one-component curable resin takes a long time to cure as described above, when the resin layer becomes thick, even if the surface portion of the resin layer is cured, the inside is not cured, There is a disadvantage that it takes a long time for the entire resin layer to cure.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a repairing agent for the surface of a wood material that can solve such inconvenience, can be easily handled, and can solidify the entire resin layer in a short time.
[0007]
[Means for Solving the Problems]
  In order to achieve such an object, the repair material on the surface of the wood material of the present invention contains an active hydrogen group having a plurality of active hydrogen groups in the molecule in the repair agent that fills the recess on the surface of the wood material and closes the recess. Urethane obtained by blending and reacting a compound and a polyisocyanate compound having a plurality of isocyanate groups in the molecule in an amount such that the isocyanate group / active hydrogen group equivalent ratio is greater than 1 (NCO / OH> 1) Includes reactive hot melt resin made of prepolymerThe active hydrogen group-containing compound is a crystalline polyester polyol having a melting point of 50 ° C. or higher obtained by reacting 1,6-hexanediol with dicarboxylic acids, and the urethane prepolymer is the urethane prepolymer. Obtained by reacting the crystalline polyester polyol in the range of 50 to 93% by weight with respect to the total amount of the polymer and the polyisocyanate compound in the range of 7 to 20% by weight with respect to the total amount of the urethane prepolymer. It is a resin.
[0008]
The repair material on the surface of the woody material of the present invention is based on the reactive hot melt resin, so it only needs to be melted by heating at the time of use, and it is not necessary to mix the main agent and the curing agent. Can be easily.
[0009]
Here, when an active hydrogen group-containing compound having a plurality of active hydrogen groups in the molecule is reacted with a polyisocyanate compound having a plurality of isocyanate groups in the molecule, the active hydrogen groups and the isocyanate groups are generated. A urethane resin having a urethane bond is obtained. However, the reactive hot melt resin is obtained by blending the active hydrogen group-containing compound and the polyisocyanate compound in an amount such that the isocyanate group / active hydrogen group equivalent ratio is greater than 1 (NCO / OH> 1). Therefore, it is a urethane prepolymer having an isocyanate group at the terminal.
[0010]
The reactive hot melt resin is solidified by cooling. At this time, the isocyanate group in the urethane prepolymer reacts with moisture in the air to form a polyurethane resin, thereby forming a three-dimensional crosslinked structure. Heat resistance can be imparted to the obtained resin.
[0011]
  Further, in the repair agent for the surface of the woody material of the present invention, the active hydrogen group-containing compound contains 1,6-hexanediol, dicarboxylic acids, and the like in order to shorten the time until the urethane prepolymer is solidified by cooling. A crystalline polyester polyol having a melting point of 50 ° C. or higher obtained by reactingTheWhen the melting point of the crystalline polyester polyol is less than 50 ° C., it takes a relatively long time for the urethane prepolymer to solidify by cooling, and the time required for repairing the surface of the wood material becomes long.
[0012]
  At this time, the urethane prepolymer is in the range of 50 to 93% by weight of the crystalline polyester polyol with respect to the total amount of the urethane prepolymer and 7 to 20% by weight with respect to the total amount of the urethane prepolymer. A resin obtained by reacting with the polyisocyanate compound.The
[0013]
When the crystalline polyester polyol exceeds 93% by weight with respect to the total amount and the polyisocyanate compound is less than 7% by weight with respect to the total amount, the number of isocyanate groups in the urethane prepolymer becomes too small, resulting in a three-dimensional crosslinked structure. Decreases and heat resistance decreases. In addition, when the crystalline polyester polyol is less than 50% by weight with respect to the total amount and the polyisocyanate compound exceeds 20% by weight with respect to the total amount, the time until the urethane prepolymer is solidified is increased, and foaming is performed. Will increase.
[0014]
In addition, since the urethane prepolymer has a relatively low softening point, the repairing agent on the surface of the woody material of the present invention may take a long time to solidify by cooling depending on the composition. Therefore, in order to reduce the time for solidification of the woody material surface of the present invention by cooling, it is preferable that the reactive hot melt resin further includes a resin having a higher softening point than the reactive hot melt resin. .
[0015]
As the resin having a higher softening point than the reactive hot melt resin, a rosin ester resin or a terpene phenol resin having a softening point in the range of 90 to 150 ° C. is used because of its excellent compatibility with the reactive hot melt resin. It is preferable to use it. If the softening point is less than 90 ° C., the effect of shortening the time for solidification of the reactive hot melt resin cannot be obtained, and if it exceeds 150 ° C., the compatibility with the reactive hot melt resin is reduced, or the repair agent This increases the viscosity of the wood material and reduces the filling performance of the wood material into the recesses.
[0016]
The reactive hot melt resin may include the rosin ester resin or terpene phenol resin in a range of 5 to 50% by weight with respect to the total amount of the reactive hot melt resin. If the content of the rosin ester resin or terpene phenol resin is less than 5% by weight based on the total amount of the resin, the effect of shortening the time for solidification of the reactive hot melt resin cannot be obtained. Adhesiveness of the agent to the wood material is lowered, or the viscosity of the repair agent is increased to reduce the filling performance of the wood material into the recesses.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in more detail.
[0018]
The repair material on the surface of the wood material according to the present embodiment fills the recesses such as cracks, grooves, wormholes, node holes, etc. on the surface of the wood material such as wood, plywood, laminated wood, and single plate laminate (LVL). It is used for plugging in and contains a reactive hot melt resin made of a urethane prepolymer as a main ingredient.
[0019]
The reactive hot melt resin is solidified by cooling after heating and melting, but in order to shorten the time until solidification, a rosin ester resin or a terpene phenol resin having a softening point in the range of 90 to 150 ° C. You may contain in the range of 5 to 50 weight% with respect to the whole quantity of this reactive hot-melt resin.
[0020]
Further, as the repair material on the surface of the woody material of the present embodiment, the reactive hot melt resin may be used alone, and ethylene-vinyl acetate is used as long as it does not affect the solidification characteristics of the reactive hot melt resin. You may mix and use at least 1 sort (s) of hot-melt resin selected from the group which consists of a copolymer-type resin, polyolefin-type resin, polyamide-type resin, and polyester-type resin.
[0021]
Moreover, the repair material on the surface of the woody material of the present embodiment contains the reactive hot melt resin as a main agent, and various additives known per se may be appropriately added thereto.
[0022]
The urethane prepolymer used as the reactive hot melt resin is composed of an active hydrogen group-containing compound having a plurality of active hydrogen groups in the molecule and a polyisocyanate compound having a plurality of isocyanate groups in the molecule. It can be obtained by blending and reacting in an amount such that the group equivalent ratio is greater than 1 (NCO / OH> 1).
[0023]
As the active hydrogen group-containing compound, a monomer having a hydroxyl group or an amine group, a prepolymer, or the like can be used. Examples thereof include polyols such as polyester polyol, polyether polyol, polycarbonate polyol, and acrylic polyol; Polyamines such as polyamines; low molecular weight alcohols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, and cyclohexanedimethanol; diamines such as propylene diamine and hexamethylene diamine; monoalcohols, monoamines, and low molecular weight aminos Alcohol, castor oil, sugar, water, etc. can be mentioned. Each of the above compounds may be used alone or in combination of two or more.
[0024]
The low molecular weight alcohols and diamines also act as carbon chain extenders for the purpose of adjusting the molecular weight, introducing hydroxyl groups, etc. to the urethane prepolymer, and the monoalcohols and monoamines are compounds containing the active hydrogen groups. And act as a reaction terminator between the polyisocyanate compound and the polyisocyanate compound. The low molecular weight amino alcohol acts as the carbon chain extender and the reaction terminator.
[0025]
Examples of the polyester polyol include polyester diols having hydroxyl groups at both ends obtained by dehydration condensation reaction of low molecular weight glycols and dicarboxylic acids, polycaprolactone diols obtained by ring-opening polymerization of ε-caprolactone, and the like. Examples of the low molecular weight glycols include ethylene glycol, diethylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, neopentyl glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1 , 5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propane Diol, 2-n-butyl-2-ethyl-1,3-propanediol, bisphenol A ethylene Kisaido adducts, can be mentioned propylene oxide adduct of bisphenol A. Examples of the dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, oxalic acid, naphthylene dicarboxylic acid, acid esters thereof, acid anhydrides, and the like. be able to. The low molecular weight glycols and dicarboxylic acid may be used alone or in combination of two or more.
[0026]
As the polyether polyol, polyether obtained by ring-opening polymerization using low molecular weight polyols or water as an initiator, using oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide alone or in admixture of two or more. Polyol: Polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran can be exemplified. Examples of the low molecular weight polyols used as an initiator for the ring-opening polymerization reaction of the oxirane compound include ethylene glycol, propylene glycol, trimethylolpropane, and glycerin.
[0027]
Examples of the polycarbonate polyol include those obtained by a dephenol reaction between low molecular weight glycols used for the synthesis of the polyester polyol and diphenyl carbonate.
[0028]
Next, as the polyisocyanate compound, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate (IPDI), phenylene diisocyanate, cyclohexyl diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated trimethylxylylene diisocyanate. 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexane-1,6-diisocyanate, 2,2,4-trimethylhexane-1,6 -MDI isomers such as diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, and polynuclear mixtures of MDI Polymethylene polyphenyl isocyanate (polymeric MDI), 4,4-dibenzyl diisocyanate, 1,5-naphthalene diisocyanate, paraphenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, tetramethylxylylene diene Examples include isocyanate, 4,4-diphenyl ether diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and the like. Further, as the polyisocyanate compound, a dimer, trimer or burette derived from the polyisocyanate monomer such as triphenylmethane-4,4 ′, 4 ″ -triisocyanate; from the polyisocyanate monomer and carbon dioxide gas The resulting polyisocyanate having a 2,4,6-oxadiline trione ring; an adduct of a low molecular weight polyol such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, cyclohexane dimethanol, and polyisocyanate; Modified compounds of isocyanate compounds with carbodiimide; compounds having an NCO terminal such as adducts of polyester polyols, polyether polyols, and polyisocyanates can also be used.As the polyisocyanate compound, each of the above compounds may be used alone, or two or more kinds thereof may be mixed and used.
[0029]
In the present embodiment, as the active hydrogen group-containing compound, obtained by reacting 1,6-hexanediol and adipic acid, polyhexane adipate diol obtained by reacting 1,6-hexanediol and sebacic acid. Polyurethane sebactate diol, crystalline polyester polyol such as polyhexane dodecanedioate diol obtained by reacting 1,6-hexanediol and dodecanedioic acid is used to cool the urethane prepolymer. It is preferable in that the solidification time can be shortened. The crystalline polyester polyol preferably has a melting point of 50 ° C. or higher in order to shorten the time for solidification by the cooling.
[0030]
Moreover, in this embodiment, it is preferable from the viewpoint of safety to use an MDI isomer such as 4,4-diphenylmethane diisocyanate (MDI) or 2,4-diphenylmethane diisocyanate as the polyisocyanate compound.
[0031]
In this embodiment, the crystalline polyester polyol in the range of 50 to 93% by weight with respect to the total amount of the urethane prepolymer, and the polyisocyanate compound in the range of 7 to 20% by weight with respect to the total amount of the urethane prepolymer. Is added, the isocyanate group / active hydrogen group equivalent ratio can be greater than 1 (NCO / OH> 1), and the urethane prepolymer is obtained by reacting the crystalline polyester polyol with the polyisocyanate compound. be able to. Since the reactive hot melt resin of the present embodiment is composed of the urethane prepolymer, the isocyanate group in the urethane prepolymer reacts with moisture in the air to form a three-dimensional crosslinked structure. Can be given heat resistance.
[0032]
As said additive added to the repair material of the woody material surface of this embodiment, while improving the adhesiveness of resin, the tackifier for reducing a melt viscosity, and improving the heat resistance and blocking resistance of resin In addition to wax, etc., facial dye, filler, thixotropic agent, thixotropic agent, antioxidant, ultraviolet absorber, stabilizer, adhesion promoter, surfactant, remaining in the urethane prepolymer Examples thereof include a catalyst for promoting the reaction between an isocyanate group and moisture in the air.
[0033]
Examples of the filler include clay, calcined clay, talc, silica, alumina, calcium carbonate, magnesium oxide, calcium silicate, calcium aluminate, sodium aluminate, magnesium silicate, calcium hydroxide, barium sulfate, and carbon black. And inorganic fillers such as silica sand, mica, silica balloon, glass balloon, and zeolite; organic fillers such as vinyl chloride powder, rubber powder, and organic balloon.
[0034]
As the thixotropic agent, inorganic thixotropic agent such as fatty acid amide wax, ultrafine silica, asbestos powder, rock wool powder, sepiolite; organic bentonite, modified polyester polyol type organic thixotropic agent; surface treatment with amide type wax, etc. Calcium carbonate, mica powder, short fiber polyethylene and the like subjected to.
[0035]
Examples of the adhesiveness-imparting agent include various titanate coupling agents, reaction products of coupling agents and isocyanate compounds, reaction products of two or more types of coupling agents, each alone or You may mix and use 2 or more types. As the reaction product of the two or more types of coupling agents, for example, reaction products of various aminosilanes and epoxysilanes, condensation reaction products of alkoxy groups of two or more molecules of coupling agents, and the like can be used.
[0036]
Examples of the catalyst include organic metal catalysts such as dibutyltin dilaurate, tin octenoate, lead octenoate and lead naphthenate; N-triethylamine, N-methylmorpholine bis (2-dimethylaminoethyl) ether, N, N, N ', N ″, N ″, N ″ -pentamethyldiethylenetriamine, N, N, N′-trimethylaminoethyl-ethanolamine, bis (2-dimethylaminoethyl) ether, N-methyl-N′-dimethyl Examples thereof include tertiary amines such as aminoethylpiperazine and imidazole compounds in which the secondary amine functional group of the imidazole ring is substituted with a cyanoethyl group. The catalysts may be used alone or in combination of two or more.
[0037]
In addition, when the additive is added to the repair material on the surface of the wood material of this embodiment, care must be taken not to affect the composition of the urethane prepolymer by subjecting the additive to a dehydration treatment in advance. There is.
[0038]
The repair material on the surface of the wood material according to the present embodiment can be filled in the recesses on the surface of the wood material by being melted by heating and solidified by cooling after the filling.
[0039]
Next, examples and comparative examples of the present invention are shown.
[0040]
[Example 1]
In this example, first, a crystalline polyester polyol having a molecular weight of 3500, a melting point of 55 ° C., and a hydroxyl value of 30.5 comprising a reaction product of 1,6-hexanediol and adipic acid (manufactured by Huls, trade name: DYNACOLL 7360). To 44 parts by weight, 44 parts by weight of an amorphous polyester polyol (trade name: DYNACOLL7210, manufactured by Huls Co., Ltd.) having a molecular weight of 3500 and a hydroxyl value of 30.5 comprising a reaction product of side chain glycol and adipic acid was added. After heating for 1 hour at a temperature of 100 ° C. under a pressure of 0.7 kPa or less, followed by heat vacuum dehydration treatment, 11.9 parts by weight of 4,4′-diphenylmethane diisocyanate was further added, and the temperature was 85 ° C. under a nitrogen stream. The reaction was carried out for 3 hours to obtain a urethane prepolymer having an NCO content of 2.0%.
[0041]
Next, the reactive hot-melt resin consisting only of the urethane prepolymer obtained in this example is used alone as a repair agent for the surface of the wood material, and the repair agent is heated and melted to form a liquid, and then the surface of the redwood material A recess having a diameter of 20 mm and a depth of 10 mm was formed and tested for performance.
[0042]
The test of the performance is to determine the surface smoothness of the repair agent filled in the recesses, the presence or absence of the occurrence of blindness, the presence or absence of occurrence of cracks, the presence or absence of occurrence of foaming, and the solidification rate at 25 ° C. ( Time until the whole resin layer solidifies), resin hardness by durometer hardness after solidification, adhesive strength, and durability in a high temperature and high humidity environment after 2 days of filling were measured.
[0043]
The adhesive strength was measured according to JIS K 6849 by adhering 15 cm-thick plywood using the repair agent and performing a tensile test to measure the tensile adhesive strength and the breaking rate. The durability under the high-temperature and high-humidity environment was determined by visually observing the peeling condition by a boiling peeling test (use environment 1) of the JAS structure laminated material.
[0044]
In the performance test, the repair material on the surface of the wood material desirably has a smooth surface of the repair agent filled in the recesses, and is free from fading, cracks, and foaming. The solidification rate at 25 ° C. is 70 Desirably within seconds. Further, the resin hardness due to the durometer hardness after solidification is desirably in the range of 30 to 65 equivalent to that of the wood material, and it is desirable that there is little peeling as durability in a high temperature and high humidity environment. The results are shown in Table 1.
[0045]
[Example 2]
In this example, first, a crystalline polyester polyol having a molecular weight of 2000, a melting point of 50 ° C. and a hydroxyl value of 56 consisting of a reaction product of 1,6-hexanediol and adipic acid (trade name: Adecan New, manufactured by Asahi Denka Kogyo Co., Ltd.) Ace Y6-22) After adding 8.4 parts by weight of the same non-crystalline polyester polyol as used in Example 1 to 75.6 parts by weight, heat vacuum dehydration treatment was performed in exactly the same manner as in Example 1. Further, 16.0 parts by weight of 4,4′-diphenylmethane diisocyanate was added and reacted in the same manner as in Example 1 to obtain a urethane prepolymer having an NCO content of 2.0%.
[0046]
Next, the performance of the repairing agent was tested in exactly the same manner as in Example 1 except that the reactive hot melt resin consisting only of the urethane prepolymer obtained in this example was used alone as a repairing agent for the surface of the wood material. did. The results are shown in Table 1.
[0047]
[Example 3]
In this example, 8.8 parts by weight of the same non-crystalline polyester polyol used in Example 1 was added to 79.3 parts by weight of the same crystalline polyester polyol used in Example 1, After heat vacuum dehydration treatment exactly as in Example 1, 11.9 parts by weight of 4,4′-diphenylmethane diisocyanate was further added and reacted in exactly the same manner as in Example 1 to give an NCO content of 2.0%. The urethane prepolymer was obtained.
[0048]
Next, the performance of the repairing agent was tested in exactly the same manner as in Example 1 except that the reactive hot melt resin consisting only of the urethane prepolymer obtained in this example was used alone as a repairing agent for the surface of the wood material. did. The results are shown in Table 1.
[0049]
[Example 4]
In this example, first, a crystalline polyester polyol having a molecular weight of 3500 comprising a reaction product of 1,6-hexanediol and adipic acid, a melting point of 61 ° C., and a hydroxyl value of 32.1 (manufactured by Asahi Denka Kogyo Co., Ltd., trade name: Adeka New Ace NS-3465) 8.8 parts by weight of the same non-crystalline polyester polyol used in Example 1 was added to 79.0 parts by weight, and the heat vacuum dehydration treatment was performed in exactly the same manner as in Example 1. After that, 12.2 parts by weight of 4,4′-diphenylmethane diisocyanate was further added and reacted in the same manner as in Example 1 to obtain a urethane prepolymer having an NCO content of 2.0%.
[0050]
Next, the performance of the repairing agent was tested in exactly the same manner as in Example 1 except that the reactive hot melt resin consisting only of the urethane prepolymer obtained in this example was used alone as a repairing agent for the surface of the wood material. did. The results are shown in Table 1.
[0051]
[Example 5]
In this example, 71.0 parts by weight of the same crystalline polyester polyol as used in Example 4, 7.9 parts by weight of the same non-crystalline polyester polyol as used in Example 1, and a softening point After adding 8.8 parts by weight of a terpene phenol resin (trade name: YS Polystar T145, manufactured by Yasuhara Chemical Co., Ltd.) at 145 ° C. and subjecting to heat vacuum dehydration treatment exactly as in Example 1, 4,4′-diphenylmethane was further added. 12.4 parts by weight of diisocyanate was added and reacted in the same manner as in Example 1 to obtain a urethane prepolymer having an NCO content of 2.0%.
[0052]
Next, the performance of the repairing agent was tested in exactly the same manner as in Example 1 except that the reactive hot melt resin consisting only of the urethane prepolymer obtained in this example was used alone as a repairing agent for the surface of the wood material. did. The results are shown in Table 1.
[0053]
[Example 6]
In this example, 71.3 parts by weight of the same crystalline polyester polyol used in Example 4, 7.9 parts by weight of the same non-crystalline polyester polyol used in Example 1, and a softening point After adding 10.0 parts by weight of a rosin ester resin (trade name: Neotol 125K, manufactured by Harima Chemicals Co., Ltd.) at 125 ° C. and subjecting to heat vacuum dehydration in exactly the same manner as in Example 1, 4,4′-diphenylmethane was further added. 10.7 parts by weight of diisocyanate was added and reacted in the same manner as in Example 1 to obtain a urethane prepolymer having an NCO content of 2.0%.
[0054]
Next, the performance of the repairing agent was tested in exactly the same manner as in Example 1 except that the reactive hot melt resin consisting only of the urethane prepolymer obtained in this example was used alone as a repairing agent for the surface of the wood material. did. The results are shown in Table 1.
[0055]
[Comparative Example 1]
In this comparative example, performance was tested in exactly the same manner as in Example 1 except that a two-component curable urethane resin (manufactured by Willamette Burley, trade name: XU-100) was used as a repair agent. The results are shown in Table 1.
[0056]
[Comparative Example 2]
In this comparative example, the performance was tested in exactly the same manner as in Example 1, except that a one-component curable urethane resin (trade name: Selecty UR-70, manufactured by Oshika Corporation) was used as a repair agent. The one-component curable urethane resin is liquid at normal temperature. The results are shown in Table 1.
[0057]
[Table 1]

[0058]
From Table 1, according to the repair agents of Examples 1 to 6, the solidification rate at 25 ° C. (time until the entire resin layer solidifies) is as fast as 65 seconds or less, and the terpene phenol having a softening point of 145 ° C. It is clear that in Example 5 where the resin was added, 43 seconds and in Example 6 where the rosin ester resin having a softening point of 125 ° C. was added, 44 seconds, which was even faster than when the terpene phenol resin or rosin ester resin was not added. is there. Moreover, it is clear that each repair agent of Examples 1-6 is excellent also in the various performance calculated | required by the repair agent of the wooden material surface.
[0059]
For each of the above examples, the repair agent made of the two-component curable urethane resin of Comparative Example 1 has a large resin loss, and the repair agent made of the one-component curable urethane resin of Comparative Example 2 has a resin loss. Although it is relatively small, it is apparent that the solidification rate at 25 ° C. is 300 seconds or more, and it takes much longer time than the repair agents of Examples 1 to 6 until the entire resin layer is solidified.

Claims (2)

In a repair agent that fills a concave portion on the surface of a wood material and closes the concave portion, an active hydrogen group-containing compound having a plurality of active hydrogen groups in the molecule and a polyisocyanate compound having a plurality of isocyanate groups in the molecule group / active hydrogen group equivalent ratio is blended in an amount of large (NCO / OH> 1) than 1, seen containing a reactive hot melt resin comprising a urethane prepolymer obtained by reacting,
The active hydrogen group-containing compound is a crystalline polyester polyol having a melting point of 50 ° C. or higher obtained by reacting 1,6-hexanediol with dicarboxylic acids.
The urethane prepolymer comprises the crystalline polyester polyol in a range of 50 to 93% by weight with respect to the total amount of the urethane prepolymer, and the polyisocyanate in a range of 7 to 20% by weight with respect to the total amount of the urethane prepolymer. A repair material for the surface of a wood material, which is a resin obtained by reacting a compound. The reactive hot melt resin further includes a rosin ester resin or a terpene phenol resin having a softening point in the range of 90 to 150 ° C. in a range of 5 to 50% by weight with respect to the total amount of the reactive hot melt resin. the healing agent according to claim 1 Symbol placing wood material surface characterized.