JP2005001372A - Resin composition for timber impregnation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for timber impregnation improved in curability, at the same time capable of insuring a satisfactory durability as a resin impregnated timber, capable of forming a cured resin film few in appearance defect such as a scratch, warp, crack or the like at the outside surface and the inside of the timber. <P>SOLUTION: The resin composition for a timber impregnation comprises a resin composition containing a (meth)acrylate polymer component and a radically polymerizable monomer component wherein the (meth)acrylate polymer component indispensably contains a crosslinking (meth)acrylate polymer having at least one radically polymerizable double bond in the molecule. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin composition for impregnating wood for impregnating the wood and then curing and integrating with the wood, and a method for producing a resin-impregnated wood in which the wood and the cured resin are integrated using the composition About.

  In recent years, in the field of buildings such as houses and offices, the preference for natural regression in living spaces is becoming stronger, the natural texture of timber is favored, and there is a demand for wood-based materials in the field of building materials as well. It is growing.

  However, if wood is used as it is in such a wood-based building material, the wood is inferior in durability against heat, water (humidity), and mechanical shock, and therefore, after construction as a building material, the color changes, decays, and changes in dimensions over time. Warping, surface cracks, breakage, etc. may occur, and the quality as a building material may not be maintained. Therefore, chemically treated wood is being studied that maintains the natural texture and feel of use of wood and has improved durability against heat, water (humidity), and mechanical shock.

  Among chemically treated wood, resin-impregnated wood is obtained by impregnating wood with a liquid curable resin or a radically polymerizable monomer (hereinafter simply referred to as a monomer) and then curing it. Since the strength and durability can be enhanced by taking advantage of the characteristics of wood, it is widely used for interior building materials such as flooring and stairs.

  Generally, in a resin composition for impregnating wood, an unsaturated polyester resin containing styrene or the like, or a (meth) acrylic polymer such as poly (methyl methacrylate) is used as a radical polymerizable monomer component such as methyl methacrylate (MMA). A dissolved acrylic syrup (for example, Patent Document 1) or the like is used. However, since the unsaturated polyester resin has insufficient weather resistance, when the resin-impregnated wood using this resin is used in a place exposed to sunlight, there is a risk of discoloration with the passage of time. The acrylic syrup is relatively excellent in weather resistance, but contains a large amount of volatile MMA. Therefore, when the resin is cured, the MMA volatilizes from the surface of the wood, and a cured resin coating is applied to the surface of the wood. The film does not form well, and the wood that is the base material is exposed, resulting in poor appearance (fading), and because it contains a large amount of monomer, the volume shrinkage due to curing also increases. After being cured, there was a risk of warping, cracking, etc. of the wood.

Furthermore, when these resin compositions are impregnated into wood and cured, if there is a portion that is in direct contact with air on the wood surface, oxygen in the air inhibits the radical polymerization reaction, so that sufficient curing occurs. It did not proceed (low curability), and stickiness (tack) remained, resulting in poor handleability, and clogging sometimes occurred in the polishing process.
JP-A-4-144704

  Therefore, in the present invention, it is excellent in curability and can secure sufficient durability as a resin-impregnated wood, and a cured resin coating film with less appearance such as blurring, less warping of wood, cracking, etc. is formed on the surface and inside of the wood. An object of the present invention is to provide a resin composition for impregnating wood that can be used.

  The resin composition for impregnating wood of the present invention is a resin composition containing a (meth) acrylic polymer component and a radically polymerizable monomer component, and the (meth) acrylic polymer component contains at least in the molecule. The gist is that a crosslinkable (meth) acrylic polymer having one radical polymerizable double bond is essential.

  The present invention also includes a method for producing a resin-impregnated wood in which wood is impregnated with the above-mentioned resin composition for impregnating wood, and then the resin composition is cured.

  By the said structure, the resin composition for wood impregnation which can form the cured resin coating film which is excellent in sclerosis | hardenability and can ensure sufficient durability as resin-impregnated wood was able to be provided. Further, the resin-impregnated wood obtained was of a high quality with few appearance defects, warpage, cracks and the like. Therefore, the resin-impregnated wood of the present invention is excellent in heat resistance, can retain durability against the influence of heat, water, mechanical impact, etc. for a long period of time, and is suitable for building members such as flooring.

  As a result of intensive studies on a resin composition for impregnating wood to be cured by impregnating the wood (hereinafter sometimes simply referred to as a resin composition), the present inventors have determined that at least one radical polymerizable property in the molecule. The resin composition in which a (meth) acrylic polymer component including a crosslinkable (meth) acrylic polymer having a double bond is used in combination with a radical polymerizable monomer has excellent curability and has poor appearance and It has been found that a cured coating film having sufficient durability as a resin-impregnated wood can be formed without causing warping and cracking. The “impregnation into wood” of the resin composition for wood impregnation of the present invention means that the resin composition penetrates from the surface of the wood and fills all or part of the voids in the wood and on the surface. Point to. The “polymer” of the present invention includes not only a binary copolymer but also a ternary or higher multi-component copolymer.

  The (meth) acrylic polymer component (hereinafter referred to as A) in the wood-impregnated resin composition of the present invention has a crosslinkable (meth) acrylic heavy polymer having at least one radical polymerizable double bond in the molecule. The union (hereinafter referred to as A1) is essential. When this crosslinkable (meth) acrylic polymer (A1) is contained in the resin composition, it causes a polymerization reaction with the polymers (A1) and the radical polymerizable monomer component at the time of heat curing. A cured coating film having high hardness can be formed. Further, since the curability is enhanced, the air contact surface is sufficiently cured. Furthermore, when the resin composition contains a plasticizer (described later), compatibility with the plasticizer is improved, and white turbidity due to separation of the plasticizer is less likely to occur during curing.

  In order to synthesize the crosslinkable (meth) acrylic polymer (A1), first, a (meth) acrylic polymer (A2) that is not crosslinkable, that is, has no radically polymerizable double bond in the molecule is synthesized. This (meth) acrylic polymer (A2) is a polymer obtained by radical polymerization of a monomer component that essentially contains the monomer (a1) having a (meth) acryloyl group. Examples of the monomer (a1) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, propyl (meth) acrylate, Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) (Meth) acrylates such as acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and the like. Combined and can be used.

  In the polymerization of the (meth) acrylic polymer (A2), together with the monomer (a1), unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid, maleic acid, fumaric acid, itaconic acid, etc. Monomers having a carboxyl group such as monoesters of these unsaturated dicarboxylic acids and monoesters of these unsaturated dicarboxylic acids, or monomers having a glycidyl group such as glycidyl (meth) acrylate, allyl glycidyl ether (a3) Need to use. By using these monomers (a2) or (a3), a carboxyl group or a glycidyl group can be introduced into the side chain of the (meth) acrylic polymer (A2). Then, the monomer (a3) is reacted with the side chain carboxyl group, or the monomer (a2) is reacted with the side chain glycidyl group to form radically polymerizable double groups in the molecule. A (meth) acrylic polymer (A1) having a bond is obtained. When the monomer (a2) is used as the monomer component for the (meth) acrylic polymer (A2), the monomer component (a3) must not be included in the monomer component, and vice versa. It is the same. This is because gelation occurs during the polymerization.

  The monomer (a2) or (a3) is preferably 0.5 to 20% by mass in 100% by mass of the monomer component for the (meth) acrylic polymer (A2). When the amount is less than 0.5% by mass, the amount of double bonds in the crosslinkable (meth) acrylic polymer (A1) is reduced, so that when the resin composition is cured, tack remains and handling properties are reduced. May decrease. A more preferred lower limit is 0.8% by mass, and a still more preferred lower limit is 1.0% by mass. On the other hand, when the ratio exceeds 20% by mass, the durability of the resin-impregnated wood obtained from the resin composition may be reduced. A more preferable upper limit value is 15% by mass, and a further preferable upper limit value is 10% by mass.

  In the synthesis of the (meth) acrylic polymer (A2), radical polymerizable double bonds other than (meth) acryloyl groups such as styrene, α-methylstyrene, vinyltoluene, N-vinylpyrrolidone, α-olefin, etc. The monomer (a4) having the above may be used in combination so as not to impair the effects of the present invention.

  As a method for synthesizing the (meth) acrylic polymer component (A2), a general polymerization reaction may be used, and examples thereof include bulk polymerization (bulk polymerization), solution polymerization, suspension polymerization, and emulsion polymerization. What is necessary is just to set reaction conditions, such as reaction temperature and reaction time in the case of the said polymerization reaction, suitably. In addition, the polymerization reaction is preferably performed in a nitrogen atmosphere, and is preferably performed by adding a chain transfer agent in order to adjust the average molecular weight. Examples of the chain transfer agent include thiol compounds such as mercaptopropionic acid, dodecyl mercaptan, and thiophenol, α-styrene dimer, and carbon tetrachloride. The addition amount of the chain transfer agent may be appropriately set depending on the type of chain transfer agent and the type of monomer component, but is in the range of 0.01 to 15 parts by mass with respect to 100 parts by mass of the monomer component. The inside is preferable.

  In the polymerization reaction, it is preferable to use a radical polymerization initiator. Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide, lauryl peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, and azo compounds such as azobisisobutyronitrile. In addition, you may terminate reaction in the middle of superposition | polymerization, and may obtain the mixture of a (meth) acrylic polymer (A2) and an unreacted monomer.

  When the (meth) acrylic polymer (A2) is obtained by polymerization, as described above, the monomer (a3) is reacted with the carboxyl group of the (meth) acrylic polymer (A2) or (meth) acrylic. By making the said monomer (a2) react with the glycidyl group of a polymer (A2), the crosslinkable (meth) acrylic polymer (A1) which has a radically polymerizable double bond in a molecule | numerator is obtained. In the reaction, it is desirable to use a known esterification catalyst.

  The average molecular weight of the crosslinkable (meth) acrylic polymer (A1) is preferably in the range of 5,000 to 500,000 in terms of number average molecular weight (Mn). If the number average molecular weight is less than 5,000, the durability of the resin-impregnated wood may be lowered. The lower limit of the number average molecular weight (Mn) is more preferably 10,000. On the other hand, when the number average molecular weight exceeds 500,000, the viscosity of the resin composition increases, and the impregnation property to wood decreases. Therefore, the upper limit of the number average molecular weight (Mn) is more preferably 100,000, and even more preferably 50,000.

  Moreover, it is preferable that the molecular weight per polymerizable double bond of the crosslinkable (meth) acrylic polymer (A1) is in the range of 200 to 100,000. If the molecular weight per monomer double bond is less than 200, the durability of the resin-impregnated wood obtained from the resin composition may be insufficient. A more preferred lower limit is 500, and a more preferred lower limit is 1,000. On the other hand, if the molecular weight per double bond exceeds 100,000, tackiness may remain when the resin composition is cured, and handling properties may be deteriorated. A more preferable upper limit value is 80,000, and a further preferable upper limit value is 50,000. In order for the molecular weight per polymerizable double bond of the crosslinkable (meth) acrylic polymer (A1) to be included in the above range, the molecular weight of the (meth) acrylic polymer (A2) and the single amount What is necessary is just to prepare the usage-amount of body (a2) * (a3) suitably.

  The (meth) acrylic polymer component (A) in the resin composition of the present invention may be composed only of the above-described crosslinkable (meth) acrylic polymer (A1), or a crosslinkable (meth) acrylic polymer. It may be a mixture of the union (A1) and the non-crosslinkable (meth) acrylic polymer (A2). When mixed and used, the crosslinkable (meth) acrylic polymer (A1) is preferably 30% by mass or more in 100% by mass of the (meth) acrylic polymer component (A). This is because if the crosslinkable (meth) acrylic polymer (A1) is not large, the effect of improving the curability and the effect of increasing the durability are not sufficiently exhibited.

  The resin composition of the present invention comprises a radical polymerizable monomer component (hereinafter referred to as B) as an essential component together with the (meth) acrylic polymer component (A). This radical polymerizable monomer component (B) is one or two or more single monomers capable of causing a radical polymerization reaction with the crosslinkable (meth) acrylic polymer (A1) to form a crosslinked structure. Consists of the body. The radical polymerizable monomer component (B) includes, for example, the monomers (a1) to (a4) exemplified as monomers that can be used when the (meth) acrylic polymer (A2) is synthesized. included.

  The radical polymerizable monomer component (B) further includes ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (Meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,3-butylene glycol di (meth) Acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentylglyco Rudi (meth) acrylate, 2,2-bis [4-((meth) acryloxyethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloxy polyethoxy) phenyl] propane, glycerol di (meth) ) Acrylate, dimethylol-tricyclodecane di (meth) acrylate, alkylene oxide adduct di (meth) acrylate of bisphenol A, alkylene oxide adduct di (meth) acrylate of trimethylolpropane, pentaerythritol di (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tetramethylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, ditrimethylolpropane Tora (meth) polyfunctional radically polymerizable monomers such as acrylate (a5) may be included.

  Among these, from the viewpoint of durability of the resin-impregnated wood, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2-bis [4-((meth) acryloxy / polyethoxy) phenyl] propane, It is preferable to use an alkylene oxide adduct di (meth) acrylate of bisphenol A, an alkylene oxide adduct di (meth) acrylate of trimethylolpropane, or polytetramethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate More preferably, polypropylene glycol di (meth) acrylate is used.

  The radically polymerizable monomer component (B) of the present invention is prepared from 2-hydroxyethyl (meth) acrylate, hydroxypropyl (hydroxypropyl) in order to improve adhesion between wood and resin and durability of the resulting resin-impregnated wood. (Meth) acrylate, hydroxybutyl (meth) acrylate, methyl (α-hydroxymethyl) acrylate, ethyl (α-hydroxymethyl) acrylate, butyl (α-hydroxymethyl) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono ( It preferably contains a monomer (a6) having a hydroxyl group such as (meth) acrylate. The ratio of the monomer (a6) having a hydroxyl group is preferably in the range of 10 to 99% by mass when the radical polymerizable monomer component (B) is 100% by mass. If the proportion of the monomer having a hydroxyl group is less than 10% by mass, the impregnation rate to the wood may be reduced, and if it exceeds 99% by mass, the curability on the air contact surface may be reduced. A more preferable lower limit of the monomer (a6) having a hydroxyl group is 20% by mass, and a more preferable lower limit is 30% by mass. Moreover, a more preferable upper limit is 95 mass%, and a more preferable upper limit is 90 mass%.

  The resin composition of the present invention may contain a plasticizer (hereinafter referred to as C). This plasticizer (C) is a (meth) acrylic polymer component (A) or radical polymerizable monomer component (B) and a non-radically polymerizable organic compound that does not cause radical polymerization. Known compounds used as agents can be used. When this plasticizer (C) is added to the resin composition, even if the resin composition shrinks as it hardens, or the resin-impregnated wood absorbs or releases moisture and its volume or shape changes, the resulting cured coating can be obtained. Since the film can follow the change, the effect of preventing cracking and warping of the resin-impregnated wood is further increased.

  Specific examples of the plasticizer (C) of the present invention include phthalic acid alkyl ester, aromatic carboxylic acid ester, aliphatic dibasic acid ester, fatty acid ester derivative, phosphoric acid ester, reaction product of carboxylic acid and epoxy compound, saturation Ester compounds such as polyester, polycaprolactone and polyether ester; compounds having an ether bond such as poly (oxyalkylene) glycol, polyvinyl formal and xylene formaldehyde resin; polyamide; polyurethane; chlorinated paraffin, polystyrene, polyolefin, polyvinyl chloride, Examples thereof include polyvinyl compounds such as polyvinyl acetate and their copolymers, grafts, and cross-linked products, and one or more can be used.

  Among these, the above-described ester compounds, compounds having an ether bond, and chlorinated paraffin are preferable in terms of good compatibility in the resin composition for impregnation with wood. In addition, poly (oxyalkylene) glycol, polyether ester, and chlorinated paraffin are preferable from the viewpoint of excellent affinity and impregnation between wood and the resin composition. In addition, the plasticizer (C) in this invention differs from the above-mentioned (meth) acrylic polymer component (A).

The resin composition for wood impregnation of the present invention contains a (meth) acrylic polymer component (A) and a radical polymerizable monomer component (B) as essential components. In a preferred embodiment, the plasticizer (C) Containing. When the resin composition for wood impregnation does not contain a plasticizer (C), in a total amount of 100 parts by mass of the (meth) acrylic polymer component (A) and the radical polymerizable monomer component (B), It is preferable that a (meth) acrylic polymer component (A) is 5-70 mass parts. When (A) is less than 5 parts by mass, tackiness remains when the resin composition is cured, resulting in poor handling properties. A more preferred lower limit of (A) is 7 parts by mass, and a more preferred lower limit is 10 parts by mass. On the other hand, when (A) exceeds 70 mass parts, the viscosity of a resin composition will become high and the impregnation property to wood will fall. A more preferable upper limit value of (A) is 60 parts by mass, and a more preferable upper limit value is 50 parts by mass.

  When the resin composition contains a plasticizer (C), the mixing ratio of the (meth) acrylic polymer component (A) is 10 to 10 parts by mass in the total amount of the components (A), (B), and (C). The amount is preferably 60 parts by mass, and more preferably 20 to 40 parts by mass. When the amount of the component (A) is less than 10 parts by mass, the appearance of the resin-impregnated wood tends to be poor, and when it exceeds 60 parts by mass, the viscosity of the resin composition increases and the impregnation into the wood decreases.

  Moreover, as a mixture ratio of a radically polymerizable monomer component (B), it is preferable that it is 10-80 mass parts in 100 mass parts of total amounts of (A), (B), (C) component, 20 More preferably, it is -70 mass parts. When the amount of the component (B) is less than 10 parts by mass, the viscosity of the resin composition becomes high and the impregnation property to the wood decreases, and when it exceeds 80 parts by mass, the appearance of the resin-impregnated wood tends to be poor.

  The blending ratio of the plasticizer (C) is preferably 10 to 80 parts by mass and preferably 15 to 50 parts by mass with respect to 100 parts by mass of the total amount of the components (A), (B) and (C). Is more preferable. If the component (C) is less than 10 parts by mass, the resin-impregnated wood may be warped or cracked, but if it exceeds 80 parts by mass, the durability of the resin-impregnated wood is lowered, which is not preferable.

  The resin composition for impregnating wood of the present invention preferably contains a curing agent (radical polymerization initiator) in order to polymerize and harden the wood composition after impregnating the wood. Examples of the curing agent include methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxy 2-ethylhexanoate, benzoyl peroxide, t-butyl peroxyiso Butyrate, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, t-butylperoxylaurate, t-hexylper Examples thereof include peroxides such as oxybenzoate, t-butyl peroxyisopropyl carbonate, 1,1-dimethylpropyl peroxyisopropyl carbonate, and azo compounds such as azobisisobutyronitrile. These start a polymerization reaction by heating.

  Instead of the thermal polymerization initiator, a photopolymerization initiator may be used as a curing agent, and polymerization and curing may be performed using active energy rays. Examples of the photopolymerization initiator include benzoin such as benzoin, benzoin methyl ether, and benzoin ethyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4- (1- acetophenones such as t-butyldioxy-1-methylethyl) acetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2, Thioxanthones such as 4-diisopropylthioxanthone and 2-chlorothioxanthone; Ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; Benzophenone, 4- (1-t-butyldioxy-1 -Methylethyl) benzophenone, benzophenones such as 3,3 ', 4,4'-tetrakis (t-butyldioxycarbonyl) benzophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- Propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-hydroxy-2-methyl-1-phenyl-propan-1-one; acylphosphine oxides And xanthones.

  As the usage-amount of the said hardening | curing agent, the inside of the range of 0.1 mass part-10 mass parts is preferable with respect to 100 mass parts of resin compositions. If the usage-amount of a hardening | curing agent is less than 0.1 mass part, there exists a possibility that hardening may not fully advance. Moreover, when the usage-amount exceeds 10 mass parts, there exists a possibility that it may become a problem in the surface of the storage stability of a composition. The more preferable lower limit of the amount of the curing agent is 0.5 part by mass, further preferably 0.8 part by mass, and the more preferable upper limit is 8 parts by mass, and further preferably 5 parts by mass.

  In the resin composition for wood impregnation of the present invention, if necessary, the (meth) acrylic polymer component (A) and the radical polymerizable monomer component (B), and a plasticizer used as necessary ( In addition to C), other compounds and auxiliary agents may be included. Examples of other compounds and auxiliary agents include antioxidants, ultraviolet absorbers, ultraviolet stabilizers, antistatic agents, color pigments, dyes, elastomers, curing accelerators, curing retarders, and the like. The amount of the other compound or auxiliary agent may be in a range that does not impair the effects of the invention, and is preferably in the range of 0.01 to 50 parts by mass with respect to 100 parts by mass of the composition.

  The wood impregnating resin composition of the present invention preferably has a viscosity at 25 ° C. of 100 Pa · s or less. When it exceeds 100 Pa · s, the viscosity becomes high and the liquid feeding operation is difficult, which causes a problem in production. A more preferable upper limit of the viscosity is 50 Pa · s, and a more preferable upper limit is 10 Pa · s.

  Using the resin composition for impregnating wood of the present invention, a resin-impregnated wood can be obtained by, for example, impregnating the composition with moisture-adjusted wood and then curing it. The wood impregnated with the resin composition according to the present invention is not particularly limited. For example, the types include conifers such as cedar, pine, rice pine (Douglas fir), cocoon, rice cocoon, Taiwan cocoon, etc. Either can be used.

  Examples of the method for impregnating the composition with wood include a dipping method, a reduced pressure injection method, a pressure injection method, a reduced pressure / pressure injection method, a coating impregnation method (a stationary method, a pressure method), and the like. It can select suitably according to a shape and a use. The shape of the wood is not particularly limited. In the case of a thin plate useful for a flooring or the like, a thickness of 0.2 to 30 mm is preferable from the viewpoint of industrially manufacturing resin-impregnated wood.

  The amount of impregnation of the wood-impregnated resin composition of the present invention into the wood may be appropriately set according to the strength and durability required for the resin-impregnated wood. It is preferable to impregnate about 200 parts by mass. If the amount of the composition is less than 2 parts by mass, the strength and durability of the resin-impregnated wood may not be sufficient, and if it exceeds 200 parts by mass, discoloration may occur in the wood due to heat generation during curing. The more preferable lower limit of the impregnation amount of the composition is 5 parts by mass, further preferably 10 parts by mass, and the more preferable upper limit is 150 parts by mass, and more preferably 100 parts by mass.

  Examples of the curing method for curing the resin composition after impregnating the wood impregnated resin composition of the present invention with the wood include, for example, a heating / pressing press, a method using heating such as hot air and infrared rays, ultraviolet rays, electronic Examples include a method of irradiating active energy rays such as rays and radiation.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the scope of the present invention is not limited only to these Examples. Unless otherwise specified, “%” indicates “mass%” and “part” indicates “mass part”.

Synthesis example 1
In a reactor equipped with a thermometer, a cooling pipe, a gas introduction pipe, and a stirrer, 95 parts of methyl methacrylate, 5 parts of methacrylic acid as a monomer having a carboxyl group, and 4 parts of n-dodecyl mercaptan as a chain transfer agent After charging, the inside of the reactor was replaced with nitrogen gas. Next, the mixture was heated to 80 ° C. while stirring, and then 1 part of 2,2′-azobisisobutyronitrile was added as a polymerization initiator to conduct a polymerization reaction for 4 hours. A mixture of the (meth) acrylic polymer and the unreacted monomer was obtained.

  Next, 10 parts of glycidyl methacrylate as a monomer having a glycidyl group and 0.03 part of zinc octylate as an esterification catalyst are added to a mixture of the (meth) acrylic polymer having a carboxyl group and an unreacted monomer. Then, after adding 0.01 part of hydroquinone as a polymerization inhibitor, the temperature was raised to 100 ° C., and an esterification reaction was carried out in an air atmosphere for 5 hours. As a result, a crosslinkable (meth) acrylic polymer No. 1 having a radically polymerizable double bond in the molecule was obtained. A mixture of 1 and unreacted monomer was obtained. The unreacted monomer is used as it is as a radical polymerizable monomer component. The solid content concentration of this mixture was 52%, and the crosslinkable (meth) acrylic polymer No. The molecular weight per one polymerizable double bond was 700, and the number average molecular weight (Mn) was 17,000. The molecular weight was measured using gel permeation chromatography (GPC; manufactured by Tosoh Corporation).

Synthesis example 2
After charging 99 parts of methyl methacrylate and 1 part of methacrylic acid in the same reaction vessel as in Synthesis Example 1, polymerization is performed in the same manner as in Synthesis Example 1, and the (meth) acrylic polymer having a carboxyl group and an unreacted monomer A mixture with the body was obtained. Next, after adding 7 parts of glycidyl methacrylate, 0.03 part of zinc octylate and 0.01 part of hydroquinone to this mixture, an esterification reaction was performed in the same manner as in Synthesis Example 1 to produce a crosslinkable (meth) acrylic polymer. Combined No. A mixture of 2 and unreacted monomer was obtained. The solid content concentration of this mixture was 60%, and the crosslinkable (meth) acrylic polymer No. The molecular weight per polymerizable double bond of 2 was 4,900, and the number average molecular weight was 18,000.

Synthesis example 3
After charging 100 parts of methyl methacrylate and 3 parts of methacrylic acid in the same reaction vessel as in Synthesis Example 1, polymerization was conducted in the same manner as in Synthesis Example 1, and a non-crosslinkable (meth) acrylic polymer No. 1 having a carboxyl group was obtained. A mixture of 3 and unreacted monomer was obtained. The comparative mixture had a solid content of 60% and a non-crosslinkable (meth) acrylic polymer No. The number average molecular weight of 3 was 20,000.

Synthesis example 4
In a reaction vessel similar to Synthesis Example 1, 456 parts of a bisphenol A type epoxy compound (trade name “Epototo YD-901”, manufactured by Tohto Kasei Co., Ltd., average epoxy equivalent 456), 86 parts of methacrylic acid, triethylamine 2. 3 parts and 0.1 part of hydroquinone as a polymerization inhibitor were charged. Next, while air was blown into this mixture, the temperature was raised to 115 ° C. and reacted for 6 hours to obtain a comparative vinyl ester having an acid value of 7.0 mg KOH / g and a number average molecular weight of 990.

Synthesis example 5
In a reaction vessel similar to Synthesis Example 1, 98 parts of methyl methacrylate, 2 parts of methacrylic acid as a monomer containing a carboxyl group, 100 parts of toluene as a solvent, and 1 part of mercaptopropionic acid as a chain transfer agent, The inside of the reactor was replaced with nitrogen gas. Next, the temperature of the above mixture was increased to 80 ° C. while stirring, and then 0.4 part of 2,2′-azobisisobutyronitrile was added as a polymerization initiator to conduct a polymerization reaction for 2.5 hours. It was. Further, the temperature was raised to 90 ° C., 0.15 part of 2,2′-azobisisobutyronitrile was added and then heated for 3 hours, and 0.6 part of hydroquinone was added to add (meth) acryl having a carboxyl group. A polymer was obtained. Next, after adding 4 parts of glycidyl methacrylate and 0.4 part of tetraphenylphosphonium bromide to the (meth) acrylic polymer having a carboxyl group, the temperature is raised to 100 ° C. while blowing air, and 5.5 parts. Crosslinkable (meth) acrylic polymer No. 1 having a time reaction and having a polymerizable double bond in the molecule. A toluene solution of 5 was obtained. This polymer solution has a solid content concentration of 43%, a viscosity of 1750 mPa · s, an acid value of 3.0, and a (meth) acrylic polymer No. 5 had a molecular weight of 3,600 and a number average molecular weight of 25,000 per polymerizable double bond.

Experiment No. 1-11
As the resin composition for impregnating wood according to the present invention, the resin obtained in Synthesis Examples 1 to 4 and the radical polymerizable monomer component were mixed at the blending ratio shown in Table 1 to obtain a resin composition. In Table 1, the polymer mixture obtained in the synthesis example is divided into a polymer and an unreacted monomer. In addition, Experiment No. 8 is a crosslinkable (meth) acrylic polymer No. 8; 2 and 28 parts, non-crosslinkable (meth) acrylic copolymer No. 2 A mixture of 28 parts of 3 was used as a (meth) acrylic polymer. The solid content concentration of this (meth) acrylic polymer was 56%.

Next, 3 parts of “Perbutyl O” (trade name; peroxide-based polymerization initiator; manufactured by Nippon Oil & Fats Co., Ltd.) as a curing agent is blended with 100 parts of the above resin composition to obtain a curing agent-containing resin composition. I got a thing. Next, a 0.6 mm thick single veneer plate is placed in a vacuum container having a vacuum port connected to a vacuum pump and a resin composition injection port, and is removed under a reduced pressure of 20 × 10 ² Pa (15 torr) for 30 minutes. I worried. While maintaining this reduced pressure state, the curing agent-blended resin composition was injected to sufficiently impregnate the veneer single plate, and after returning to normal pressure, it was allowed to stand for 3 hours. Take out the veneer veneer impregnated with the resin composition, remove excess resin composition, and sandwich both sides of this veneer with a 25 μm thick polyethylene terephthalate (PET) film and press at 125 ° C. and 1 MPa. And cured for 10 minutes. The PET film was removed to obtain a resin-impregnated wood. The obtained resin-impregnated wood was evaluated by the following method, and the results are shown in Table 3.

Experiment No. 12-18
The crosslinkable (meth) acrylic polymer No. 1 obtained in Synthesis Example 5 was used so that the blending ratio shown in Table 2 was obtained. 5, a radical polymerizable monomer and a plasticizer were mixed, and toluene was deaerated at 70 to 90 ° C. and 1.33 × 10 ⁴ Pa (100 mmHg) for 2 hours to obtain a resin composition. Experiment No. Resin-impregnated wood was obtained in the same manner as in 1-11. The evaluation results are shown in Table 4.

Evaluation Method (1) Viscosity Using a B-type viscometer defined in JIS K7117-1, the viscosity of the resin composition at 25 ° C. was measured.

(2) Impregnation rate The following formula impregnation rate (%) = 100 × [(mass of resin-impregnated wood) − (mass of unimpregnated wood)] / (mass of unimpregnated wood)
Based on this, the impregnation rate of the composition was calculated.

(3-1) Surface state of resin-impregnated wood (presence of tack)
Due to the feeling of touching the surface of the resin-impregnated wood with your finger, the following criteria ○… No tack (stickiness),
X: Evaluated with tack.

(3-2) Surface condition of resin-impregnated wood (presence or absence of clogging in the polishing finish process)
The surface of the resin-impregnated wood is reciprocated 20 times with a hand sander (manufactured by Ryobi Corp .; sandpaper # 240), and whether the sandpaper is clogged is visually checked as follows. Clogging is observed. X: The clogging is remarkable and evaluated.

(4) Heat resistance test I
One side of the resin-impregnated wood is polished with sandpaper (# 240), the resin-impregnated wood is placed on a 15 mm-thick plywood previously coated with a urethane adhesive, and a PET film having a thickness of 25 μm is further placed thereon. Then, thermocompression bonding was performed at 125 ° C. and 1 MPa for 5 minutes. The obtained plywood adhesive resin-impregnated wood is placed in a thermostat at 80 ° C. ± 3 ° C., taken out every 24 hours, and the occurrence of cracks on the surface is visually checked as follows. The occurrence of cracks is observed x: Evaluation was made by observing the occurrence of large cracks.

(5) Surface hardness Using a pencil scratch hardness tester, when the surface of the resulting resin-impregnated wood was scratched 5 times with a pencil core subjected to a load of 1 kg, the surface was scratched twice. Among pencils that are less than 1, the hardness symbol of the hardest pencil was defined as the surface hardness.

(6-1) Surface condition of resin-impregnated wood (presence of faintness)
Visually observe the uniformity of the coating film on the surface of the resin-impregnated wood. The following standards ○: The resin coating film is uniformly formed on the wood. × ... The resin coating film is not uniformly formed on the wood. However, there was an exposed part and evaluated.

(6-2) Surface state of resin-impregnated wood (presence or absence of turbidity of cured product)
The following criteria are visually observed for the presence or absence of turbidity on the surface of the resin-impregnated wood: ○… A transparent resin coating is formed on the wood. Δ… A slightly cloudy resin coating is formed on the wood. × ... Evaluated by the cloudiness of the resin coating on the wood.

(7) Heat resistance test II
A resin composition was prepared at a blending ratio shown in Table 2, and “Perbutyl O” (trade name; peroxide polymerization initiator; manufactured by NOF Corporation) was used as a curing agent for 100 parts of the resin composition. Two parts were blended to obtain a curing agent-blended resin composition. Next, a 0.6 mm thick single veneer plate is placed in a vacuum container having a vacuum port connected to a vacuum pump and a resin composition injection port, and is removed under a reduced pressure of 20 × 10 ² Pa (15 torr) for 30 minutes. I worried. While maintaining this reduced pressure state, the curing agent-blended resin composition was injected to sufficiently impregnate the veneer single plate, and after returning to normal pressure, it was allowed to stand for 3 hours. After taking out the veneer veneer impregnated with the resin composition, and draining off the excess resin composition, the resin-impregnated wood is placed on a 15 mm-thick plywood previously coated with a urethane adhesive, Further, a PET film having a thickness of 25 μm was placed thereon, followed by thermocompression bonding at 125 ° C. and 1 MPa for 10 minutes to cure the resin.

  Experiment No. About 17 and 18, after heat-curing resin as follows, the heat test II was done. In the above resin composition containing a curing agent, “Darocur 1173” (“Darocur” is a registered trademark; 2-hydroxy-2-methyl-1-phenyl-propan-1-one; photopolymerization initiator; Used by Merck & Co., Ltd.), and the glazed veneer was impregnated with resin in the same manner as described above. Take out the veneer veneer impregnated with the resin composition, remove the excess resin composition, cover both sides with a PET film with a thickness of 25 μm, and 10 cm below the high-pressure ultraviolet lamp (80 W / cm) with an output of 2 kW. The side was passed through at a speed of 2 m / min to cure the resin. Thereafter, the resin-impregnated wood after photocuring after peeling the PET film was placed on a 15 mm-thick plywood previously coated with a urethane-based adhesive, and a PET film having a thickness of 25 μm was placed thereon again. And thermocompression bonded at 125 ° C. and 1 MPa for 5 minutes.

Each obtained plywood adhesive resin-impregnated wood is put in an incubator at 80 ° C. ± 3 ° C., taken out every 24 hours, and the state of occurrence of cracks on the surface is visually checked according to the following criteria. The occurrence of small cracks is observed. X: Evaluation was made by observing the occurrence of large cracks.

(8) Dimensional change rate A square of about 10 cm × about 10 cm was marked on the resin-impregnated wood with a magic, the four sides were measured accurately, and immersed in deionized water at 25 ° C. for 24 hours. Take out after immersion and put in an incubator at 80 ° C ± 3 ° C for 8 hours, and then measure the length of the four sides of the squares filled in, the following formula (dimensional change rate) (%) = (after water immersion and heating) Measured value) / (initial measured value) × 100
Based on the above, the dimensional change rate was calculated.

  As is clear from Table 3, the experiment No. which is an example of the present invention. The wood impregnating resin compositions 1 to 8 were able to ensure a sufficient impregnation rate, and no tack or clogging on the surface of the resin-impregnated wood was observed. The resin-impregnated wood impregnated and cured with the wood-impregnating resin composition has excellent heat resistance and high surface hardness, and therefore has excellent durability.

  On the other hand, Experiment No. For No. 9, since a non-crosslinkable (meth) acrylic polymer was used, tack remained (low surface curability), and clogging occurred slightly in the polishing step. In addition, Experiment No. In No. 10, since the (meth) acrylic polymer is not blended, all the characteristics are inferior. Experiment No. 11 is an example using a vinyl ester resin, but all the properties were inferior to those of the examples of the present invention.

  Further, as apparent from Table 4, Experiment No. which is an example of the present invention to which a plasticizer was added. The resin composition for wood impregnation of 12 to 18 was able to ensure a sufficient impregnation rate, and it was difficult for the resin impregnated wood to be faint and cloudy. It can be seen that the resin-impregnated wood impregnated and cured with this wood-impregnating resin composition is excellent in heat resistance and has a low dimensional change rate. In particular, when compared with Table 3, it was confirmed that the system to which the plasticizer was added had even better heat resistance.

Claims (5)

  A resin composition comprising a (meth) acrylic polymer component and a radically polymerizable monomer component, the (meth) acrylic polymer component having at least one radically polymerizable double bond in the molecule. A wood-impregnated resin composition characterized by containing a crosslinkable (meth) acrylic polymer.   The wood impregnation resin composition according to claim 1, further comprising a plasticizer.   The wood impregnation according to claim 2, wherein when the total amount of the (meth) acrylic polymer component, the radical polymerizable monomer component and the plasticizer is 100 parts by mass, the plasticizer is contained in an amount of 10 to 80 parts by mass. Resin composition.   The wood impregnating resin composition according to claim 1 or 2, wherein a part or all of the radical polymerizable monomer component is a hydroxyl group-containing radical polymerizable monomer. A method for producing resin-impregnated wood, comprising impregnating wood with the resin composition for impregnating wood according to claim 1 and then curing the resin composition.