Wood repairing agent and preparation method thereof

Abstract

The invention provides a wood repairing agent and a preparation method thereof. The wood repairing agent comprises the following raw materials: polyvinyl alcohol, konjac glucomannan, a vinyl ester monomer, a carboxyl-containing ethylenically unsaturated monomer, an acrylamide derivative, a dihydrazide compound, wood fiber powder, an inorganic filler, tragacanth gum powder, tackifying resin, an auxiliary agent and water. According to the wood repairing agent, modified polyvinyl alcohol and konjac glucomannan are adopted as mixed protection glue, multiple modified vinyl ester polymer is adopted as main emulsion, and wood fiber powder, inorganic filler, tackifying resin and the like are added; the wood repairing agent has the advantages of favorable water resistance, favorable wood adhesive force, favorable shrinkage cracking resistance and excellent processing and polishing properties.

Description

Technical Field

[0001] This invention relates to the field of wood processing technology, specifically to a wood repair agent and its preparation method. Background Technology

[0002] In the process of wood processing and solid wood furniture manufacturing, defects such as wood damage, cracking, wormholes, and dead knots are frequently encountered. These defects affect the aesthetics, practicality, and workability of the wood. Especially with the increasing scarcity of wood resources, the repair process for defective wood is becoming increasingly crucial in the application of precious woods. Efficient and high-quality repairs can not only improve wood utilization but also reduce production costs. The core of repair effectiveness and efficiency lies in the wood repair materials. Although there are many types of wood repair agents on the market, they have obvious shortcomings: In terms of repair quality, they have poor adhesion, poor compatibility and wettability with the wood matrix, and are prone to falling off or lifting at the edges; they have weak shrinkage and crack resistance, and are prone to internal stress during curing, or cracking and interface separation due to mismatch between temperature and humidity changes and wood expansion and contraction; they have poor water resistance, and are prone to swelling and softening in humid environments, with damage aggravated after wet and dry cycles; their processing and sanding performance is also not ideal, with hardness not matching the wood, too soft a material sticking to sandpaper, and too hard a material abrading the surrounding wood, making it difficult to obtain a smooth surface to achieve "seamless repair".

[0003] For example, patent CN103862539A discloses a wood repair agent, which is composed of 40-50% by weight of floor primer, 30-40% by weight of ethyl cyanoacrylate, 1-2% by weight of fumed silica, 1-2% by weight of acrylic / styrene copolymer emulsion, 1-3% by weight of benzotriazole, 3-5% by weight of soft resin, and 0.5-2% by weight of carbonate. The floor is coated with a primer using a sanding process, wherein the primer includes synthetic resin and 15-20% by weight of talc. The repair agent uses "floor primer debris" as a filler skeleton; it is itself waste material after bonding with wood, and its surface is coated with synthetic resin, resulting in low activity and poor crack resistance.

[0004] Therefore, there is an urgent need in this field for a wood repair agent that, in addition to adhesion, water resistance, and processing and sanding performance, also possesses excellent shrinkage resistance, crack resistance, and high repair quality, in order to meet actual production needs. Summary of the Invention

[0005] To address the problems existing in the prior art, a wood repair agent and its preparation method are provided. The wood repair agent uses modified polyvinyl alcohol and konjac glucomannan as a mixed protective adhesive, multiple modified ethylene ester polymer as the main emulsion, and adds wood fiber powder, inorganic fillers, tackifying resins, etc., so that the wood repair agent has good water resistance, good wood adhesion, resistance to shrinkage and cracking, and excellent processing and sanding performance.

[0006] In one aspect, a wood repair agent is provided, comprising the following raw materials: polyvinyl alcohol, konjac glucomannan, ethylene ester monomer, carboxyl-containing olefinic unsaturated monomer, acrylamide derivative, diacylhydrazine compound, wood fiber powder, inorganic filler, tragacanth gum powder, tackifying resin, additives, and water.

[0007] In some embodiments, the wood repair agent, by weight, comprises the following raw materials: 20-40 parts polyvinyl alcohol, 10-20 parts konjac glucomannan, 400-500 parts ethylene ester monomer, 10-20 parts carboxyl-containing olefinic unsaturated monomer, 2-5 parts acrylamide derivative, 1-2 parts dihydrazide compound, 150-300 parts wood fiber powder, 80-180 parts inorganic filler, 10-15 parts tragacanth gum powder, 45-60 parts tackifying resin, 2.5-10 parts additives, and 400-510 parts water.

[0008] In some embodiments, the wood repair agent, by weight, comprises 20, 25, 30, 35, or 40 parts of polyvinyl alcohol. In some embodiments, the wood repair agent, by weight, comprises 10, 12, 14, 16, 18, or 20 parts of konjac glucomannan. In some embodiments, the wood repair agent, by weight, comprises 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, or 500 parts of ethylene ester monomer. In some embodiments, the wood repair agent, by weight, comprises 10, 12, 14, 16, 18, or 20 parts of carboxyl-containing olefinic unsaturated monomer. In some embodiments, the wood repair agent, by weight, comprises 2, 2.5, 3, 3.5, 4, or 5 parts of acrylamide derivative. In some embodiments, the wood repair agent comprises, by weight, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2 parts of the raw material dihydrazide compound.

[0009] In some embodiments, the wood repair agent, by weight, comprises 150 parts, 200 parts, 250 parts, or 300 parts of raw material wood fiber powder. In some embodiments, the wood repair agent, by weight, comprises 80 parts, 100 parts, 140 parts, 160 parts, or 180 parts of raw material inorganic filler. In some embodiments, the wood repair agent, by weight, comprises 10 parts, 12 parts, or 15 parts of raw material tragacanth gum powder. In some embodiments, the wood repair agent, by weight, comprises 45 parts, 50 parts, 55 parts, or 60 parts of raw material tackifying resin. In some embodiments, the wood repair agent, by weight, comprises 2.5 parts, 5 parts, 7.5 parts, or 10 parts of raw material additives. In some embodiments, the wood repair agent, by weight, comprises 400 parts, 410 parts, 420 parts, 430 parts, 440 parts, 450 parts, 460 parts, 470 parts, 480 parts, 490 parts, 500 parts, or 510 parts of raw water.

[0010] In some embodiments, the polyvinyl alcohol is a modified polyvinyl alcohol. Preferably, the modified polyvinyl alcohol is selected from at least one of Kuraray KL-318, Kuraray KM-618, and Kuraray R-1130.

[0011] In some embodiments, the content of the konjac glucomannan (KGM) is ≥95% (w / w)%.

[0012] This invention uses polyvinyl alcohol and konjac glucomannan as a mixed protective colloid. Due to its large molecular weight and abundance of hydrophilic groups such as hydroxyl and carbonyl groups, konjac glucomannan aggregates with water molecules through hydrogen bonds and dipole interactions to form supramolecular structures, thus exhibiting excellent thickening properties. It also provides excellent emulsification in emulsion polymerization. Combined with polyvinyl alcohol, this protective colloid facilitates polymerization and improves the adhesion and consistency of the emulsion. Furthermore, as a natural high-molecular-weight polysaccharide, konjac glucomannan also possesses excellent emulsion water-holding capacity, allowing for slow evaporation of water during the subsequent wood repair and curing process, reducing the likelihood of surface cracking.

[0013] In some embodiments, the ethylene ester monomer includes vinyl acetate and / or ethylene tert-carbonate.

[0014] In some embodiments, the ethylene ester monomer includes vinyl acetate and ethylene tert-carbonate; preferably, the mass ratio of vinyl acetate to ethylene tert-carbonate is (45~75):(25~55); more preferably, the mass ratio is 45:55, 55:45, 65:35 or 75:25; this mass ratio is mainly to control the glass transition temperature Tg of the polymer obtained by the ethylene ester monomer at -5~15°C.

[0015] Since ethylene tert-carbonate is a branched unsaturated higher fatty acid ester, copolymerizing ethylene tert-carbonate with vinyl acetate transfers its strong hydrophobic properties to the copolymer chain, overcoming the problem of insufficient water resistance in vinyl acetate polymers. The polymerization reactivity ratio of ethylene tert-carbonate is similar to that of vinyl acetate, and their copolymerization is beneficial to the polymerization reaction. The polymer molecular structure is also quite regular and stable, not easily activated and broken by ultraviolet light, giving it good weather resistance, alkali resistance, and adhesion to fillers and pigments.

[0016] In some embodiments, the carboxyl-containing olefinic unsaturated monomer is selected from at least one of acrylic acid or methacrylic acid.

[0017] In this invention, olefinic unsaturated monomers containing carboxyl groups are used as modifying monomers. The introduced carboxyl groups provide active sites for subsequent reactions. They can form strong hydrogen bonds or coordination bonds with polar groups (such as hydroxyl groups and metal oxides) on the wood surface, thereby enhancing the adhesion of the wood repair agent.

[0018] In some embodiments, the acrylamide derivative is selected from at least one of diacetone methacrylamide or diacetone acrylate. Preferably, the acrylamide derivative is diacetone methacrylamide.

[0019] In some embodiments, the diacylhydrazine compound is selected from at least one of autodiacid diacylhydrazine, sebacylhydrazine, or diacylhydrazine carbonate. Preferably, the diacylhydrazine compound is adipic acid diacylhydrazine.

[0020] In this invention, during the polymerization reaction of ethylene ester monomers, acrylamide derivatives and diacylhydrazine compounds are added as modifying monomers. Ketone carbonyl groups are introduced into the polymer through copolymerization. During the curing process of the repair agent, after water evaporates, the hydrazine groups and ketone carbonyl groups in the diacylhydrazine compound come into contact and undergo a room temperature self-crosslinking reaction, which further improves the water resistance and weather resistance of the wood repair agent and also improves the bonding force between materials.

[0021] In some embodiments, the wood fiber powder has a fiber length of 10-2000 μm and a fiber density of 0.8-1.3 g / cm³. 3 Preferably, the wood fiber powder is selected from at least one of coniferous wood fiber powder, broadleaf wood fiber powder, and non-wood plant fiber powder.

[0022] In this invention, wood fiber powder is used as a filler in the repair agent. Due to the capillary effect of the wood fiber structure, internal moisture can be rapidly transported to the surface and interface of the repair agent, resulting in a uniform distribution of moisture within the repair agent system. This significantly reduces skinning, extends the processing time, and significantly improves bonding strength and surface strength. Simultaneously, the structure of the wood fiber also reduces the tension of the repair agent during the drying process, thus significantly reducing cracking.

[0023] In some embodiments, the inorganic filler is selected from at least one of bentonite, light calcium carbonate powder, or attapulgite.

[0024] In this invention, inorganic fillers are mixed with wood fiber powder to make a repair agent with a density between 0.386-1.18 g / cm3 and a hardness of 450-2600 bf. Its texture is similar to that of wood, so it is easy to sand and process after wood repair and does not easily damage tools.

[0025] In some embodiments, the tackifying resin is selected from at least one of rosin resin, 138 modified rosin resin, or 2402 phenolic resin.

[0026] In this invention, the tackifying resin in the wood repair agent can improve the initial tack and adhesion to wood of the system. By interacting with polymer chain segments, the tackifying resin reduces the movement resistance of the polymer chain and promotes the diffusion and entanglement of molecular chains at the interface, thereby enhancing the initial tack and holding power of the material. The phenolic hydroxyl, hydroxymethyl, carboxyl, ester, and ether groups contained in the tackifying resin form a hydrogen bond network structure with the polymer emulsion, resin, and wood fiber powder, which can greatly reduce resin precipitation and plasticizer migration, thereby enhancing the stability of the repair agent.

[0027] In this invention, tragacanth gum in the wood repair agent functions as a thickener, emulsifier, and stabilizer. Tragacanth gum is a bifunctional emulsifier, increasing the viscosity of the aqueous phase while reducing the interfacial tension between the oil and aqueous phases; therefore, the addition of tragacanth gum makes the wood repair agent emulsion system more stable.

[0028] In some embodiments, the adjuvant includes an initiator. Preferably, the initiator is ammonium persulfate or potassium persulfate. In some embodiments, the initiator is 2.5 to 4 parts by weight; preferably 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 parts.

[0029] In some embodiments, the adjuvant further includes at least one of a buffer, an antifoaming agent, and a bactericide. In some embodiments, the antifoaming agent is Solvay Rhodoline mineral oil defoamer DF691; the bactericide is Dow's KATHON® LX150 antifungal bactericide; and the buffer is sodium bicarbonate.

[0030] Secondly, a method for preparing a wood repair agent is provided, comprising the following steps: 1) Add tragacanth gum powder to water, mix well and let stand until the gum is fully hydrated to obtain gum solution, set aside for use; add tackifying resin to solvent, stir to dissolve, and prepare tackifying resin solution, set aside for use; 2) Add polyvinyl alcohol and konjac glucomannan to water, mix well, heat to the reaction temperature 1, and add initiator and ethylene ester monomer dropwise to carry out polymerization reaction to obtain seed emulsion; 3) After adding an initiator to the seed emulsion obtained in step 2), add ethylene ester monomer, carboxyl-containing olefinic unsaturated monomer, acrylamide derivative, and dihydrazide compound. The polymerization reaction is carried out at reaction temperature 2 until the addition is complete. Then, add an initiator. After the initiator is added, the temperature is raised to reaction temperature 3 and the polymerization reaction is carried out at reaction temperature 3 to obtain a semi-finished wood repair agent emulsion. 4) After the semi-finished emulsion obtained in step 3) is cooled to below 50°C, the resin liquid obtained in step 1), wood fiber powder, inorganic filler, and tackifying resin solution obtained in step 1) are stirred and added, and mixed evenly to obtain the wood repair agent.

[0031] In some embodiments, in step 1), the solvent is an organic solvent, such as ethanol, isopropanol, toluene, etc., which can effectively dissolve the tackifying resin. This invention does not impose any special limitations.

[0032] In some embodiments, in step 1), a plasticizer is also added to the solvent. The plasticizer may be a terephthalate (e.g., di(2-ethylhexyl) terephthalate), an aliphatic diester (e.g., di(2-ethylhexyl) adipate, di(2-ethylhexyl) azelaate, di(2-ethylhexyl) diacid, etc.), as long as it can play a plasticizing role. The present invention does not impose any special limitations.

[0033] In some embodiments, in step 2), heating to reaction temperature 1 means heating to 85-95°C, holding at that temperature for 50-70 minutes, and then cooling to 90-80°C; in step 3), reaction temperature 2 is 80±2°C, and reaction temperature 3 is 85-95°C.

[0034] In some embodiments, in step 2), the ethylene ester monomer is added for 30-45 minutes; in step 3), the ethylene ester monomer, the carboxyl-containing olefinic unsaturated monomer, the acrylamide derivative, and the dihydrazide compound are added for 4-5 hours.

[0035] In some embodiments, in step 4), after the semi-finished emulsion obtained in step 3) is cooled to below 50°C, at least one of a buffer, defoamer, and bactericide is added.

[0036] Compared with the prior art, one of the above technical solutions has the following advantages or beneficial effects: The wood repair agent of the present invention uses polyvinyl alcohol and konjac glucomannan as a mixed protective adhesive. During the curing process of the wood repair agent, the moisture evaporates slowly, which does not easily cause surface cracking.

[0037] The wood repair agent of the present invention uses a multi-modified vinyl ester polymer as the main emulsion, which significantly improves its water resistance.

[0038] The wood repair agent of the present invention is modified with carboxyl-containing olefinic unsaturated monomers, acrylamide derivatives, and dihydrazide compounds to modify the ethylene ester polymer, so that the repair agent undergoes a room temperature self-crosslinking reaction during the curing process, which further improves the water resistance, weather resistance and bonding strength between materials.

[0039] The wood repair agent of the present invention has good crack resistance due to the addition of wood fiber powder; the texture of the wood repair agent after curing is similar to that of wood, which makes it easy to sand and process and does not easily damage processing tools.

[0040] The wood repair agent of the present invention contains yarrow gum, which makes the repair agent emulsion system stable and easy to store; in addition to increasing the adhesion between the repair agent and the wood, the addition of tackifying resin also improves the stability of the repair agent.

[0041] Terminology Explanation Certain embodiments of the invention will now be described in detail, examples of which are illustrated by the accompanying structural and chemical formulas. The invention is intended to cover all alternatives, modifications, and equivalents, all of which are included within the scope of the invention as defined in the claims. Those skilled in the art will recognize that many similar or equivalent methods and materials can be used to practice the invention. The invention is by no means limited to the methods and materials described herein. In the event that one or more of the incorporated documents, patents, and similar materials differ from or contradict this application (including, but not limited to, defined terminology, application of terminology, described techniques, etc.), this application shall prevail.

[0042] It should be further appreciated that certain features of the invention, for clarity, have been described in multiple independent embodiments, but may also be provided in combination in a single embodiment. Conversely, various features of the invention, for brevity, have been described in a single embodiment, but may also be provided individually or in any suitable sub-combination.

[0043] Unless otherwise stated, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. All patents and publications related to this invention are incorporated herein by reference in their entirety.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] In the following content, all numbers disclosed herein, whether or not they use words such as "approximately" or "about," are approximate values. The value of each number may vary by 1%, 2%, 5%, 7%, 8%, 10%, 15%, or 20%. Whenever a number with a value of N is disclosed, any numbers with values ​​of N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15%, or N+ / -20% will be explicitly disclosed, where "+ / -" indicates addition or subtraction. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0047] All reagents used in this invention can be purchased commercially or prepared by the methods described in this invention.

[0048] Example 1 A wood repair agent, by weight, comprises the following raw materials: 30 parts of modified polyvinyl alcohol KL-318, 12 parts of konjac glucomannan, 330 parts of vinyl acetate, 120 parts of tert-butyl carbonate, 13.5 parts of acrylic acid, 3 parts of diacetone acrylate, 1.6 parts of adipic acid dihydrazide, 2.8 parts of ammonium persulfate, 200 parts of coniferous wood fiber powder, 130 parts of bentonite, 10 parts of tragacanth gum powder, 50 parts of rosin resin, 2 parts of DF-691 defoamer, 1.8 parts of sodium bicarbonate, 3 parts of KATHON® LX150 mildew inhibitor and bactericide, and 485 parts of water.

[0049] The preparation method of the wood repair agent includes the following steps: 1) Add 10 parts of tragacanth gum powder to 40 parts of water, stir at room temperature to disperse evenly, and let stand for 10-20 hours to fully hydrate with glue to obtain a gum solution for later use; add 50 parts of rosin resin to 100 parts of toluene, stir and disperse until completely dissolved to obtain a tackifying resin solution for later use; mix vinyl acetate and vinyl tert-carbonate monomers evenly to obtain a mixed monomer for later use; prepare ammonium persulfate into a 5% aqueous solution for later use.

[0050] 2) Add defoamer to 445 parts of water, add modified polyvinyl alcohol KL-318 and konjac glucomannan under dispersion and stirring conditions, stir and disperse for 10 minutes, raise the temperature to 90℃, keep the temperature for 60 minutes, then lower the temperature to 85℃, add 1 / 3 of the ammonium persulfate solution prepared in step 1), and slowly add 1 / 6 of the mixed monomers prepared in step 1), and finish the addition in 30 minutes to obtain the seed emulsion.

[0051] 3) Maintain the temperature at 80±2℃. Continue adding half of the ammonium persulfate solution prepared in step 1) to the seed emulsion, then slowly add the remaining mixed monomers over 4-5 hours. After the monomers are added, add the remaining ammonium persulfate solution prepared in step 1), completing the addition in 15 minutes. Raise the temperature to 90℃ and maintain it for 60 minutes to obtain the semi-finished wood repair agent emulsion.

[0052] 4) After the semi-finished emulsion obtained in step 3) has cooled to below 50°C, stir and add the resin solution obtained in step 1) and disperse for 15 minutes. Then add coniferous wood fiber powder, bentonite, sodium bicarbonate and antifungal agent KATHON® LX150, and stir and disperse for 30 minutes. Finally, slowly add the tackifying resin solution obtained in step 1) and stir until uniform.

[0053] 5) Inspect the appearance, viscosity, and solid content of the adhesive. If the inspection is qualified, it can be filtered and packaged.

[0054] Example 2 A wood repair agent, by weight, comprises the following raw materials: 25 parts modified polyvinyl alcohol KL-618, 18 parts konjac glucomannan, 320 parts vinyl acetate, 150 parts tert-butyl carbonate, 13.8 parts methacrylic acid, 3.2 parts diacetone acrylate, 1.6 parts adipic acid dihydrazide, 2.8 parts potassium persulfate, 165 parts coniferous wood fiber powder, 165 parts bentonite, 10.4 parts tragacanth gum powder, 48 parts rosin resin, 2 parts DF-691 defoamer, 1.8 parts sodium bicarbonate, 3 parts KATHON® LX150 mildew inhibitor and bactericide, and 478.6 parts water.

[0055] The preparation method of the wood repair agent includes the following steps: 1) Add 10.4 parts of tragacanth gum powder to 41.6 parts of water, stir at room temperature until fully dispersed, then let stand for 10-20 hours before using glue to fully hydrate and prepare a resin solution for later use; add 48 parts of rosin resin to 72 parts of toluene, stir and disperse until completely dissolved to prepare a tackifying resin solution for later use; mix vinyl acetate and vinyl tert-carbonate monomers evenly to prepare a mixed monomer for later use; prepare a 5% (w / w) aqueous solution of potassium persulfate for later use.

[0056] 2) Add 2 parts of defoamer to 437 parts of water, and add modified polyvinyl alcohol KL-318 and konjac glucomannan under dispersion and stirring conditions. After stirring and dispersing for 10 minutes, heat to 90℃ and keep warm for 60 minutes. Then cool down to 85℃, add 1 / 3 of the potassium persulfate solution prepared in step 1), and slowly add 1 / 6 of the mixed monomers prepared in step 1). The addition is completed in 30 minutes to obtain the seed emulsion.

[0057] 3) Maintain the temperature at 80±2℃. Continue to add 1 / 2 of the potassium persulfate solution prepared in step 1) to the seed emulsion, then slowly add the remaining mixed monomers over 4-5 hours. After the monomers are added, add the remaining potassium sulfate solution prepared in step 1), completing the addition in 15 minutes. Raise the temperature to 90℃ and maintain the temperature for 60 minutes to obtain the semi-finished wood repair agent emulsion.

[0058] 4) After the semi-finished emulsion obtained in step 3) has cooled to below 50°C, stir and add the resin solution obtained in step 1) and disperse for 15 minutes. Then add coniferous wood fiber powder, bentonite, sodium bicarbonate and antifungal agent KATHON® LX150, and stir and disperse for 30 minutes. Finally, slowly add the tackifying resin solution obtained in step 1) and stir until uniform.

[0059] 5) Inspect the appearance, viscosity, and solid content of the adhesive. If the inspection is qualified, it can be filtered and packaged.

[0060] Example 3 A wood repair agent, by weight, comprises the following raw materials: 15 parts modified polyvinyl alcohol KL-318, 15 parts modified polyvinyl alcohol KL-618, 15 parts konjac glucomannan, 300 parts vinyl acetate, 110 parts tert-butyl carbonate, 12.3 parts acrylic acid, 3 parts diacetone acrylate, 1.2 parts adipic acid dihydrazide, 2.7 parts ammonium persulfate, 260 parts hardwood fiber powder, 100 parts bentonite, 10 parts tragacanth gum powder, 48 parts rosin resin, 2 parts DF-691 defoamer, 1.8 parts sodium bicarbonate, 3 parts KATHON® LX150 antifungal and bactericidal agent, and 502 parts water.

[0061] The preparation method of the wood repair agent includes the following steps: 1) Add 10 parts of tragacanth gum powder to 40 parts of water, stir at room temperature until fully dispersed, then let stand for 10-20 hours to fully hydrate with glue, and prepare a gum solution for later use; add 48 parts of rosin resin to 72 parts of toluene, stir and disperse until completely dissolved, and prepare a tackifying resin solution for later use; mix vinyl acetate and vinyl tert-carbonate monomers evenly to prepare a mixed monomer for later use; prepare a 5% (w / w) aqueous solution of ammonium persulfate for later use.

[0062] 2) Add defoamer to 462 parts of water, and add modified polyvinyl alcohol KL-318, modified polyvinyl alcohol KL-618 and konjac glucomannan under dispersion and stirring conditions. After stirring and dispersing for 10 minutes, heat to 90℃ and keep warm for 60 minutes. Then cool down to 85℃ and add 1 / 3 of the ammonium persulfate solution prepared in step 1). Slowly add 1 / 6 of the mixed monomers prepared in step 1) and finish adding in 30 minutes to obtain the seed emulsion.

[0063] 3) Maintain the temperature at 80±2℃. Continue adding half of the ammonium persulfate solution obtained in step 1) to the seed emulsion, and then slowly add the remaining mixed monomers over 4-5 hours. After the monomers are added, add the remaining ammonium persulfate solution over 15 minutes. Raise the temperature to 90℃ and keep it at that temperature for 60 minutes to obtain the semi-finished wood repair agent emulsion.

[0064] 4) After the semi-finished emulsion obtained in step 3) has cooled to below 50°C, stir and add the resin solution obtained in step 1) and disperse for 15 minutes. Then add wood fiber powder, bentonite, sodium bicarbonate and antifungal agent KATHON® LX150, and stir and disperse for 30 minutes. Finally, slowly add the tackifying resin solution obtained in step 1) and stir until uniform.

[0065] 5) Inspect the appearance, viscosity, and solid content of the adhesive. If the inspection is qualified, it can be filtered and packaged.

[0066] Example 4 A wood repair agent, by weight, comprises the following raw materials: 30 parts modified polyvinyl alcohol R-1130, 12 parts konjac glucomannan, 320 parts vinyl acetate, 160 parts tert-butyl carbonate, 14.5 parts acrylic acid, 3.6 parts diacetone acrylate, 1.3 parts adipic acid dihydrazide, 2.9 parts ammonium persulfate, 210 parts hardwood fiber powder, 120 parts bentonite, 12 parts tragacanth gum powder, 60 parts 2402 phenolic resin, 2 parts DF-691 defoamer, 1.8 parts sodium bicarbonate, 3 parts KATHON® LX150 antifungal and bactericidal agent, and 449 parts water.

[0067] The preparation method of the wood repair agent includes the following steps: 1) Add 12 parts of tragacanth gum powder to 48 parts of water, stir at room temperature until fully dispersed, then let stand for 10-20 hours before using glue to fully hydrate and prepare a resin solution for later use; add 60 parts of 2402 phenolic resin to 90 parts of toluene, stir and disperse until completely dissolved to prepare a tackifying resin solution for later use; mix vinyl acetate and ethylene tert-carbonate monomers evenly to prepare a mixed monomer for later use; prepare a 5% (w / w) aqueous solution of ammonium persulfate for later use.

[0068] 2) Add defoamer to 401 parts of water, and add modified polyvinyl alcohol R-1130 and konjac glucomannan under dispersion and stirring conditions. After stirring and dispersing for 10 minutes, heat to 90℃ and keep warm for 60 minutes. Then cool down to 85℃ and add 1 / 3 of the ammonium persulfate solution prepared in step 1). Slowly add 1 / 6 of the mixed monomers prepared in step 1) and finish adding in 30 minutes to obtain the seed emulsion.

[0069] 3) Maintain the temperature at 80±2℃. Continue adding half of the ammonium persulfate solution obtained in step 1) to the seed emulsion, and then slowly add the remaining mixed monomers over 4-5 hours. After the monomers are added, add the remaining ammonium persulfate solution over 15 minutes. Raise the temperature to 90℃ and keep it at that temperature for 60 minutes to obtain the semi-finished wood repair agent emulsion.

[0070] 4) After the semi-finished emulsion obtained in step 3) has cooled to below 50°C, stir and add the resin solution obtained in step 1) and disperse for 15 minutes. Then add the hardwood fiber powder, bentonite, sodium bicarbonate and antifungal agent KATHON® LX150, and stir and disperse for 30 minutes. Finally, slowly add the tackifying resin solution obtained in step 1) and stir until homogeneous.

[0071] 5) Inspect the appearance, viscosity, and solid content of the adhesive. If the inspection is qualified, it can be filtered and packaged.

[0072] Comparative Example 1 The components and preparation method of the wood repair agent are basically the same as those in Example 1; the difference from Example 1 is that the wood repair agent does not contain ethylene tert-carbonate, and the amount of vinyl acetate is 450 parts; the mixed monomer in step 1) of the preparation method is a single monomer of vinyl acetate.

[0073] Comparative Example 2 The composition and preparation method of the wood repair agent are basically the same as those in Example 1; the difference from Example 1 is that no wood fiber powder is added to the wood repair agent.

[0074] Comparative Example 3 The components and preparation method of the wood repair agent are basically the same as those in Example 1; the difference from Example 1 is that the wood repair agent does not contain modified polyvinyl alcohol KL-318 and konjac glucomannan.

[0075] Comparative Example 4 The composition and preparation method of the wood repair agent are basically the same as those in Example 1; the difference from Example 1 is that the wood repair agent does not contain carboxyl-containing olefinic unsaturated monomers, acrylamide derivatives, or dihydrazide compounds.

[0076] Performance testing: Adhesion test: The test was conducted according to the standard GB / T 33333-2016 Test method for tensile shear strength of wood adhesives.

[0077] Cracking and shrinkage tests: Prepare a pine board / panel to encompass a hole ranging from 1 / 4 inch to 3 / 4 inch in diameter. Fill the hole with wood repair compound. Allow the wood repair compound to dry for approximately 2 days (48 hours) and observe the surface for any shrinkage or cracking.

[0078] Water resistance: in accordance with standard HG / T3828-2006 standard for water-based wood coatings for indoor use.

[0079] The performance tests of the products prepared according to the above embodiments are shown in Table 2 below:

[0080] The performance test data from Comparative Examples 1-4 and Examples 1-4 of this application show that the repair agent of the present invention has good adhesion and strong bonding force (high dry shear strength) to wood, and can be used to break down materials in wood-to-wood bonding tests. Konjac glucomannan has a large molecular weight, good thickening and emulsion water-holding properties, and can maintain slow evaporation of water during curing, without causing surface cracking. The invention uses wood fiber powder as the main filler. Due to the coarse particle size and low bulk density of the wood fiber powder, the capillary action of the fiber structure can quickly transfer internal moisture to the surface and interface of the slurry, resulting in uniform moisture distribution within the slurry system, extending the open time, and reducing tension during drying, thus playing a significant anti-cracking role.

[0081] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. A wood repair agent, characterized by, The raw materials include polyvinyl alcohol, konjac glucomannan, vinyl ester monomer, carboxyl-containing ethylenically unsaturated monomer, acrylamide derivative, dihydrazide compound, wood fiber powder, inorganic filler, tragacanth powder, tackifying resin, auxiliary agent, and water.

2. The wood repair compound according to claim 1, characterized in that The raw materials include, by weight fraction, 20-40 parts of polyvinyl alcohol, 10-20 parts of konjac glucomannan, 400-500 parts of vinyl ester monomer, 10-20 parts of carboxyl-containing ethylenically unsaturated monomer, 2-5 parts of acrylamide derivative, 1-2 parts of dihydrazide compound, 150-300 parts of wood fiber powder, 80-180 parts of inorganic filler, 10-15 parts of tragacanth powder, 45-60 parts of tackifying resin, 2.5-10 parts of auxiliary agent, and 400-510 parts of water.

3. The wood repair compound according to claim 1 or 2, characterized in that The vinyl ester monomer includes vinyl acetate or / and tertiary carbonic acid vinyl ester; The carboxyl-containing ethylenically unsaturated monomer is selected from at least one of acrylic acid or methacrylic acid; The acrylamide derivative is selected from at least one of bisacetyl methacrylamide or bisacetyl acrylamide; The dihydrazide compound is selected from at least one of adipic acid dihydrazide, sebacic acid dihydrazide, or carbonic acid dihydrazide; The polyvinyl alcohol is modified polyvinyl alcohol; The wood fiber powder has a fiber length of 10-2000 um and a fiber density of 0.8-1.3 g / cm 3 ; The inorganic filler is selected from at least one of bentonite, light calcium carbonate powder, or attapulgite; The tackifying resin is selected from at least one of rosin resin, 138 modified rosin resin, or 2402 phenolic resin; The auxiliary agent includes initiator.

4. The wood repair compound of claim 3, wherein The vinyl ester monomer includes vinyl acetate and tertiary carbonic acid vinyl ester; the mass ratio of the mixed monomers of vinyl acetate and tertiary carbonic acid vinyl ester is (45-75):(25-55).

5. The wood repair compound of claim 3, wherein The modified polyvinyl alcohol is selected from at least one of Kuraray KL-318, Kuraray KM-618, or Kuraray R-1130; the wood fiber powder is selected from at least one of coniferous wood fiber powder, broad-leaved wood fiber powder, and non-wood plant fiber powder.

6. The wood repair compound of claim 3, wherein The auxiliary agent further includes at least one of buffering agent, defoaming agent, and bactericide.

7. A method of preparing the wood repair agent according to any one of claims 1 to 7, characterized in that, The method includes the following steps: 1) adding tragacanth powder into water, mixing, and standing until the glue is fully hydrated to obtain a tragacanth solution; adding tackifying resin into solvent, stirring and dissolving to obtain a tackifying resin solution; 2) adding polyvinyl alcohol and konjac glucomannan into water, mixing, and heating to reaction temperature 1; sequentially adding initiator, vinyl ester monomer, and performing polymerization to obtain a seed emulsion; 3) adding initiator into the seed emulsion obtained in step 2), then adding vinyl ester monomer, carboxyl-containing ethylenically unsaturated monomer, acrylamide derivative, and dihydrazide compound, and performing polymerization at reaction temperature 2 until the addition is completed; then adding initiator, heating to reaction temperature 3, and performing polymerization at reaction temperature 3 to obtain a wood repair agent semi-finished product emulsion; 4) after the semi-finished product emulsion obtained in step 3) is cooled to below 50℃, adding the tragacanth solution obtained in step 1), wood fiber powder, inorganic filler, and the tackifying resin solution obtained in step 1), and mixing uniformly to obtain a wood repair agent.

8. The preparation method according to claim 7, characterized in that, In step 4), after the semi-finished emulsion prepared in step 3) is cooled to below 50℃, at least one of a buffering agent, a defoaming agent and a bactericide is added.

9. The preparation method according to claim 7 or 8, characterized in that, In step 2), the heating to reaction temperature 1 is heating to 85-95℃, holding for 50-70 minutes, and then cooling to 90-80℃; in step 3), the reaction temperature 2 is 80±2℃, and the reaction temperature 3 is 85-95℃.

10. The method of claim 7 or 8, wherein the step of applying the coating is performed by a method selected from the group consisting of: spray coating, dip coating, spin coating, and combinations thereof. In step 2), the dropping time of the ethylene ester monomer is 30-45 minutes; in step 3), the dropping time of the ethylene ester monomer, the carboxyl-containing ethylenically unsaturated monomer, the acrylamide derivative and the dihydrazide compound is 4-5 hours.

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