An adhesive, its preparation method and application

Abstract

The present invention discloses an adhesive, a preparation method thereof and an application thereof, belonging to the technical field of adhesives. The adhesive comprises a macromolecular initiator, one or more vinyl monomers and a solvent; the macromolecular initiator has a structural unit of at least one amide group and a carboxyl group and / or its ammonium salt, and an α-methylstyrene structural unit, and the adhesive is prepared by a free radical polymerization method. The present invention also provides an article of a component formed by using the adhesive. The polymer containing an α-methylstyrene unit and a structural unit of an amide group and a carboxyl group and / or its ammonium salt serves as an initiator, an emulsifier and a stabilizer in the emulsion polymerization process. Compared with the traditional emulsion polymerization, the composition of this polymerization system is simple, and the surface of the emulsion polymerization product is clean, without the residue of an emulsifier or a stabilizer, which can improve the performance of the product.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and particularly relates to an adhesive and its preparation method and application. Background Art

[0002] At present, adhesives and coatings mainly produced from formaldehyde are widely used in the production of products such as wood-based panels, paper, and fabrics. They are simple to prepare and low in price. However, various products produced from such adhesives or coatings will continuously release formaldehyde during use, seriously threatening the health of residents. Without using formaldehyde, monomers such as acrylate, styrene, and vinyl acetate can also be used to prepare adhesives and coatings by emulsion polymerization. However, components such as emulsifiers and stabilizers need to be added during the emulsion polymerization process, which will contaminate the surface of latex particles and affect the performance of related products. Although the current problem can be solved by using reactive emulsifiers, such as CN112063246B uses allyloxy nonylphenol polyoxyethylene ether sulfate, allyl ether sulfonate, etc. as reactive emulsifiers for emulsion polymerization, the price of such substances is relatively high.

[0003] α-Methylstyrene mainly comes from the by-products generated during the industrial production of acetone and phenol by cumene oxidation. Its price is relatively low. The polymer chain of α-methylstyrene homopolymer can break and generate free radicals above a certain temperature, and can be used as a macromolecular initiator for free radical polymerization. However, this homopolymer is not water-soluble and lacks emulsifying or stabilizing effects on monomers, making it difficult to be applied to aqueous polymerization systems (emulsion polymerization, suspension polymerization).

[0004] Therefore, if an α-methylstyrene copolymer with both emulsifying and initiating effects can be developed and used for polymerizing to prepare coatings and adhesives, it is of great significance to the coatings and adhesives industries. Summary of the Invention

[0005] The purpose of the present invention is to provide an adhesive and its preparation method and application. The adhesive has the advantages of being safe, environmentally friendly, low-cost, easy to apply, and excellent in performance.

[0006] Another purpose of the present invention is to provide a wood-based panel formed by wood veneer and the adhesive and a method for manufacturing the wood-based panel.

[0007] Another purpose of the present invention is to provide a method for manufacturing decorative paper using the adhesive and paper.

[0008] To achieve the above purposes, the present invention provides the following solutions:

[0009] An adhesive, the adhesive comprising a macromolecular initiator, one or more vinyl monomers, and a solvent;

[0010] The macromolecular initiator has a hydrophilic unit and an α-methylstyrene structural unit; the hydrophilic unit is a structural unit containing at least one amide group and a carboxyl group and / or its ammonium salt.

[0011] In the present invention, taking advantage of the characteristic that above a certain temperature, the polymer chain of the α-methylstyrene copolymer can undergo a chain-breaking reaction to generate free radicals, it is developed into a novel macromolecular initiator. The introduction of the α-methylstyrene unit can generate free radicals. The structural unit of the amide group and the carboxyl group and / or its ammonium salt in the present invention is a hydrophilic unit, and the α-methylstyrene structural unit is a hydrophobic unit. The combination of the two further endows the copolymer with amphiphilicity and can emulsify oil-soluble monomers. Finally, due to the charge effect of the carboxyl group and the amide group, such copolymers can be used as stabilizers in emulsion polymerization. Therefore, the polymer containing the α-methylstyrene unit and the structural unit of the amide group and the carboxyl group and / or its ammonium salt acts as an initiator, an emulsifier, and a stabilizer in the process of emulsion polymerization. Compared with traditional emulsion polymerization, the composition of this polymerization system is simple, and the surface of the emulsion polymerization product is clean without residual emulsifier or stabilizer, which can improve the performance of the product.

[0012] Further, in the binder, the macromolecular initiator is obtained by reacting copolymer A with ammonia, and copolymer A is a copolymer of α-methylstyrene and a monomer having a carbon-carbon unsaturated double bond and an acid anhydride group.

[0013] Further, in the binder, the monomer having a carbon-carbon unsaturated double bond and an acid anhydride group is selected from monoethylenically unsaturated dicarboxylic anhydrides having 4-8 carbon atoms, preferably maleic anhydride, itaconic anhydride, citraconic anhydride, methylene malonic anhydride, and mixtures thereof, and more preferably maleic anhydride.

[0014] Further, the polymerization of α-methylstyrene and maleic anhydride is carried out according to a molar ratio of 1:1.

[0015] Further, in the binder, the vinyl monomer is selected from at least one of the following monomers: monoethylenically unsaturated C3-C8 monocarboxylic acids, C1-C 10 alkyl esters of monoethylenically unsaturated C3-C8 monocarboxylic acids, amides of monoethylenically unsaturated C3-C8 monocarboxylic acids, vinyl alkyl ethers having C1-C8 alkyl groups, C1-C 20 vinyl esters of carboxylic acids, methoxypolyethylene glycol (meth)acrylate, (meth)acrylic acid glycidyl ester, ethylenically unsaturated monomers containing hydroxyl groups, styrene, styrene substituted with one or more substituents selected from alkyl groups, alkoxy groups, and halogens, vinylpyrrolidone, (meth)acrylonitrile, N-vinylformamide, or vinylsiloxane monomers.

[0016] Further, in the adhesive, the solvent is selected from one or more of water, alcohols, ketones, dioxane, tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide.

[0017] Further, in the adhesive, the dosage of the vinyl monomer is 10-120% of the mass of the solvent;

[0018] The dosage of the macromolecular initiator is 5-60% of the mass of the vinyl monomer, preferably 30-50%.

[0019] A method for preparing the adhesive includes the following steps:

[0020] a) Providing a reaction mixture, the reaction mixture containing a macromolecular initiator, one or more vinyl monomers, and a solvent;

[0021] b) Purging the reaction mixture with an inert gas to exclude oxygen, and then polymerizing the reaction mixture by free radical polymerization to obtain the adhesive.

[0022] Further, in the method for preparing the adhesive, the reaction temperature of the free radical polymerization is 70-100 °C, preferably 80-90 °C, and the reaction time is 0.5-8 hours, preferably 2-4 hours.

[0023] The adhesive is used in the preparation of wood-based panels, paper, cloth, or coatings.

[0024] Further, relative to the total mass of the wood-based panel, decorative paper, cloth, or coating, the dosage of the adhesive is 1-200% based on the solid content.

[0025] A wood-based panel is formed by lignocellulosic materials and the above adhesive.

[0026] A decorative paper is formed by paper and the above adhesive.

[0027] The present invention discloses the following technical effects:

[0028] (1) The adhesive of the present invention presents an emulsion state, has simple synthesis steps, and low production costs.

[0029] (2) The adhesive of the present invention can be used for both cold pressing and bonding of wood at room temperature and hot pressing and bonding of wood at high temperature, with wide applications.

[0030] (3) The copolymer developed in the present invention, which contains α-methylstyrene units, amide groups, carboxyl groups and / or carboxylate groups, serves as both an initiator and an emulsifier and stabilizer during the emulsion polymerization process. Compared with traditional emulsion polymerization, the composition of this system is simpler, and the problem of residual emulsifier or stabilizer on the surface of the emulsion polymerization product is avoided. Detailed Description of the Invention

[0031] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0032] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0034] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0035] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0036] The room temperature in the present invention refers to 25 ± 2°C.

[0037] Unless otherwise specified, the percentages in the examples are weight percentages, and the parts in the examples are parts by mass.

[0038] Sources of chemicals used: α-methylstyrene (purity 99+%, Alfa Aesar (Tianjin) Chemical Co., Ltd.); benzoyl peroxide (purity 97%, Alfa Aesar (Tianjin) Chemical Co., Ltd.); azobisisobutyronitrile (purity 98%, Shanghai Aladdin Biochemical Technology Co., Ltd.); ammonia water (concentration 20-25%, Beijing Innochem Science & Technology Co., Ltd.); ammonia gas (purity 99.999%, Beijing Haipu Gas Co., Ltd.); methyl methacrylate (purity 99%, Alfa Aesar (Tianjin) Chemical Co., Ltd.); vinyl acetate (purity 99%, Alfa Aesar (Tianjin) Chemical Co., Ltd.); other chemical reagents are all of analytical grade and purchased from Beijing Yili Fine Chemical Co., Ltd.).

[0039] Adhesive and its preparation method

[0040] One aspect of the present invention relates to an adhesive, which comprises a macroinitiator, one or more vinyl monomers and a solvent, and is prepared by radical polymerization.

[0041] The macroinitiator is a macroinitiator having a structural unit with at least one amide group and a carboxyl group and / or its ammonium salt, and an α-methylstyrene structural unit.

[0042] According to a preferred embodiment of the present invention, a part (e.g., 1-10% by weight) of the carboxyl groups of the macroinitiator may be in the form of its ammonium salt.

[0043] The molecular weight of the macroinitiator can be any molecular weight suitable for the radical polymerization of vinyl monomers. For example, the molecular weight of the macroinitiator can be not more than 2000, such as not more than 3000 or not more than 5000.

[0044] According to a preferred embodiment of the present invention, the molar content of the α-methylstyrene structural unit in the macroinitiator can be 30-70%, such as 40%, 50%, 60%, based on the total molar amount of the repeating units of the macroinitiator.

[0045] According to a preferred embodiment of the present invention, the macroinitiator is derived from a copolymer A comprising a monomer having a carbon-carbon unsaturated double bond and an acid anhydride group and α-methylstyrene, and the copolymer has at least one repeating unit with an acid anhydride group attached thereto. In a preferred embodiment, the macroinitiator is obtained from the reaction of the α-methylstyrene-acid anhydride copolymer with ammonia.

[0046] According to a preferred embodiment of the present invention, the anhydride groups on the α-methylstyrene-acid anhydride copolymer are introduced into the α-methylstyrene-acid anhydride copolymer by polymerization of at least one monomer having a carbon-carbon unsaturated double bond and an anhydride group. The monomer having a carbon-carbon unsaturated double bond and an anhydride group may be selected from monoethylenically unsaturated dicarboxylic anhydrides having 4 to 8 carbon atoms, preferably maleic anhydride, itaconic anhydride, citraconic anhydride, methylene malonic anhydride, and mixtures thereof, more preferably maleic anhydride.

[0047] The polymerization of the monomer having a carbon-carbon unsaturated double bond and an anhydride group with other monomers having a carbon-carbon unsaturated double bond for preparing the α-methylstyrene-acid anhydride copolymer can be carried out using an oil-soluble radical initiator. The oil-soluble radical initiator includes, for example, azo initiators or peroxide initiators. The azo initiators include: azobisisobutyronitrile (AIBN), azobisisoheptonitrile (ABVN), dimethyl azobisisobutyrate, etc.; the peroxide initiators include: benzoyl peroxide (BPO), diisopropylbenzene peroxide, bis(2,4-dichlorobenzoyl) peroxide, di-tert-butyl peroxide, lauroyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, and dicyclohexyl peroxydicarbonate, etc. The amount of the initiator is 0.05-10% by weight based on the weight of the monomers, preferably 1-6% by weight.

[0048] The polymerization reaction can be carried out in the presence of a solvent. The solvent may include one or more mixtures of carboxylic acid esters, ketones, and aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, cycloalkanes, etc.

[0049] Examples of aromatic hydrocarbons may include toluene, xylene, or ethylbenzene.

[0050] The carboxylic acid esters may include C1-C8 alkyl esters, phenyl esters or benzyl esters of C1-C6 carboxylic acids and C1-C8 alkyl esters of aromatic carboxylic acids having 6-10 carbon atoms. Specific examples may include ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, ethyl isobutyrate, ethyl isoamylate, isoamyl isoamylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, ethyl phenylacetate, propyl phenylacetate, butyl phenylacetate, isoamyl phenylacetate and other ester solvents.

[0051] The ketones may be selected from acetone, butanone, cyclohexanone, methyl isobutyl ketone, and methyl isopropyl ketone.

[0052] The alkanes may be selected from n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, and isooctane.

[0053] The polymerization reaction can be carried out in the presence of an inert gas such as nitrogen. The temperature of the polymerization reaction is generally 55 - 120 °C, preferably 60 - 100 °C; the time of the polymerization reaction is generally 1 - 12 hours, preferably 2 - 8 hours. After the polymerization reaction, the obtained α-methylstyrene - anhydride copolymer can be separated and dried.

[0054] In a preferred embodiment, the polymerization reaction is carried out by precipitation polymerization. The precipitation polymerization can be carried out by selecting a solvent that can dissolve the monomers but cannot dissolve the obtained α-methylstyrene - anhydride copolymer. By precipitation polymerization, the α-methylstyrene - anhydride copolymer in powder form can be directly obtained.

[0055] According to the present invention, the α-methylstyrene - anhydride copolymer can be reacted with ammonia to obtain a macroinitiator. The reaction generally includes reacting the α-methylstyrene - anhydride copolymer with ammonia under stirring at a temperature below 100 °C, preferably 15 - 70 °C, such as at room temperature. The reaction time is generally 1 - 16 hours, preferably 6 - 12 hours.

[0056] The conversion rate of the anhydride groups of the α-methylstyrene - anhydride copolymer generally exceeds 90%, preferably exceeds 95%, more preferably exceeds 98%, such as 100%.

[0057] In the reaction of the α-methylstyrene - anhydride copolymer with ammonia, the carboxyl group can also form an ammonium salt with ammonia.

[0058] The molecular weight of the α-methylstyrene - anhydride copolymer generally corresponds to that of the macroinitiator. As described above, the macroinitiator can have any molecular weight suitable for the radical polymerization of vinyl monomers. According to an embodiment of the present invention, for example, the molecular weight of the macroinitiator can be not more than 2000, such as not more than 3000 or not more than 5000.

[0059] When specifically applying the macroinitiator to polymerize vinyl monomers, the solid macroinitiator can be dissolved in a solvent, optionally mixed with at least one vinyl monomer to obtain a reaction mixture, the reaction mixture is purged with an inert gas to exclude oxygen, and then the reaction mixture is polymerized by radical polymerization to obtain an adhesive.

[0060] The vinyl monomer is selected from at least one of the following: monoethylenically unsaturated C3 - C8 monocarboxylic acids, C1 - C 10 alkyl esters of monoethylenically unsaturated C3 - C8 monocarboxylic acids, amides of monoethylenically unsaturated C3 - C8 monocarboxylic acids, vinyl alkyl ethers having C1 - C8 alkyl groups, C1 - C 20Vinyl esters of carboxylic acids, methoxypolyethylene glycol (meth)acrylates, glycidyl (meth)acrylates, ethylenically unsaturated monomers containing hydroxyl groups, styrene, styrenes substituted with one or more substituents selected from alkyl, alkoxy and halogen, vinylpyrrolidone, (meth)acrylonitrile, N-vinylformamide, vinylsiloxane monomers.

[0061] In the free radical polymerization of vinyl monomers, the solvent is selected from one or more of water, alcohols, ketones, dioxane, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide.

[0062] In the free radical polymerization, the amount of vinyl monomer used is 10-120% of the mass of the solvent.

[0063] In the free radical polymerization, the amount of the macroinitiator used is 5-60% of the mass of the vinyl monomer, preferably 30-50%.

[0064] In the free radical polymerization, the reaction system needs to be stirred, and the stirring speed is 100-400 rpm, preferably 200-300 rpm. Additionally, according to an embodiment of the present invention, the free radical polymerization can also be carried out without stirring.

[0065] In the free radical polymerization, the reaction temperature is 70-100 °C, preferably 80-90 °C.

[0066] In the free radical polymerization, the reaction time is 0.5-8 hours, preferably 2-4 hours.

[0067] In the adhesive of the present invention, in addition to the macroinitiator, if necessary, the adhesive of the present invention can also contain at least one additive. The additive can be one or more of the following: deoxidizer, emulsifier, dye, pigment, anti-migration aid, UV absorber, biocide, defoamer, colorant, antistatic agent and antioxidant.

[0068] In addition, in the present invention, the application of the adhesive in the preparation of artificial boards, decorative papers, fabrics or coatings is also provided.

[0069] There is no particular limitation on the amount of the adhesive used, and it can be appropriately adjusted according to the actual use. Relative to the total mass of the artificial board, decorative paper, fabric or coating, the amount of the adhesive used is 1-200% based on the solid content. In some preferred embodiments, relative to the total mass of the product (artificial board, decorative paper, fabric or coating), the amount of the adhesive used is preferably 1-50% by mass, more preferably 2-40% by mass, still more preferably 3-35% by mass, further preferably 5-30% by mass, and particularly preferably 7-25% by mass based on the solid content.

[0070] In some other preferred embodiments, the amount of the binder is preferably 20 to 140% by mass, more preferably 30 to 120% by mass, still more preferably 60 to 100% by mass, and particularly preferably 80 to 100% by mass relative to the total amount of the article.

[0071] In some preferred embodiments, the article of the present invention is a wood-based panel formed from lignocellulosic materials and the binder of the present invention. The wood-based panel of the present invention should be understood in a broad sense, that is, a panel formed from any lignocellulosic material and the binder composition of the present invention. The wood-based panel of the present invention is not limited to those formed solely from wood, and may also include panels formed from materials such as bamboo and straw as described below. The wood-based panel of the present invention can be various types of wood-based panels. In one embodiment, the wood-based panel includes, but is not limited to, particle board, plywood, fiber board, density board, straw board, and finger-jointed board.

[0072] The lignocellulosic material can be in the form of sawdust, chips, wood chips, strips, flakes, fibers, sheets, wood shavings, wood shavings, particles, and similar materials, as well as combinations of these materials such as a combination of strips and sawdust.

[0073] The lignocellulosic material can be processed by various conventional techniques. Large pieces of wood can be processed into wood chips in a log chipper. Large pieces of wood and scraps can also be cut into chips. Large pieces of wood can also be planed in a ring planer. Usually, the large pieces of wood are debarked before planing.

[0074] The wood-based panel of the present invention can generally be obtained by various methods known in the art. In some specific embodiments, the wood-based panel of the present invention can be prepared by the following method, which includes pressing a mixture of the lignocellulosic material and the binder composition of the present invention at a temperature of 105 to 300 °C and a pressure of 0.4 to 10 MPa, preferably pressing for 2 to 60 minutes, more preferably pressing for 3 to 30 minutes, such as 5 to 30 minutes. In some preferred embodiments, the pressing is carried out at a temperature of 120 to 220 °C and / or at a pressure of 1 to 6 MPa.

[0075] The mixture of the lignocellulosic material and the binder of the present invention for pressing can be prepared by mixing the lignocellulosic material with the binder of the present invention.

[0076] In addition, in some other preferred embodiments of the present invention, the binder of the present invention preferably fills the gaps between the lignocellulosic materials at room temperature conditions, that is, cold pressing bonding. The method includes pressing a mixture of the lignocellulosic material and the binder composition of the present invention at a temperature of 20 to 70 °C and a pressure of 0.4 to 10 MPa, preferably pressing for 60 to 600 minutes, more preferably pressing for 180 to 300 minutes, such as 200 to 300 minutes.

[0077] Finally, the present invention also relates to a method for preparing paper products, and the operation steps include paper impregnation, pre-curing, and hot pressing steps.

[0078] In the paper impregnation, the amount of the binder based on the solid content is 1-100% by weight, preferably 2-40% by weight, more preferably 3-35% by weight or 4-30% by weight, such as 5-25% by weight, 6-25% by weight, 7-25% by weight, 8-19% by weight, based on the total weight of the paper.

[0079] In the pre-curing, it is preferable to remove a part of the moisture in the paper and the binder. For example, the moisture content of the paper and the binder is reduced to less than 30% by weight, preferably less than 25% by weight, such as less than 22% by weight, or less than 18% by weight. The moisture content of the composite is generally higher than 5% by weight or higher than 8% by weight. The removal of the moisture can be carried out by heating. For example, the heating temperature can be 50-90 °C, preferably 60-80 °C.

[0080] In a preferred embodiment, the hot pressing process is carried out at a temperature of 120-220 °C and / or under a pressure of 1-6 MPa, preferably pressing for 2-60 minutes, more preferably pressing for 3-10 minutes, such as 5-10 minutes.

[0081] Example 1

[0082] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate, and 0.2 g of AIBN into a 250 mL round-bottom flask, fully dissolve, and then deoxygenate by passing nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction, separate the product, wash it with petroleum ether 3 times, and dry it in an oven at 50 °C to constant weight to obtain the α-methylstyrene / maleic anhydride copolymer;

[0083] (2) Take 20 g of the above α-methylstyrene / maleic anhydride copolymer, stir it at room temperature in an ammonia atmosphere for 16 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0084] (3) Add 50 g of deionized water, 8.59 g of butyl acrylate, 6.71 g of methyl methacrylate, and 6.12 g of the α-methylstyrene / maleamic acid copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 10 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 200 rpm at 90 °C for 4 hours to obtain an emulsion.

[0085] Example 2

[0086] (1) Add 17.7 g of α-methylstyrene, 14.7 g of itaconic anhydride, 162 g of toluene, and 0.3 g of ABVN to a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 50 °C and react for 12 hours. After the reaction is completed, separate the product, wash it three times with petroleum ether, and dry it in an oven at 50 °C to a constant weight to obtain the α-methylstyrene / itaconic anhydride copolymer;

[0087] (2) Take 20 g of the above α-methylstyrene / itaconic anhydride copolymer, 5 g of ammonia water, and 100 g of deionized water, stir at room temperature for 12 hours, then add 100 g of acetone to precipitate the product, filter, and dry to obtain the α-methylstyrene / itaconamic acid copolymer;

[0088] (3) Add 50 g of deionized water, 5 g of ethanol, 4.58 g of cyclohexyl acrylate, 10.73 g of methyl methacrylate, and 6.12 g of the α-methylstyrene / itaconamic acid copolymer to a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0089] Example 3

[0090] (1) Add 17.7 g of α-methylstyrene, 14.7 g of succinic anhydride, 60 g of cyclohexanone, 100 g of n-hexane, and 0.3 g of AIBN to a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it three times with petroleum ether, and dry it in an oven at 50 °C to a constant weight to obtain the α-methylstyrene / succinic anhydride copolymer;

[0091] (2) Take 20 g of the above α-methylstyrene / succinic anhydride copolymer and 8 g of ammonium carbonate, stir at 50 °C for 12 hours to obtain the α-methylstyrene / succinamic acid copolymer;

[0092] (3) Add 50 g of deionized water, 2 g of dioxane, 12.15 g of vinyl acetate, 3.16 g of methyl methacrylate, 4.22 g of styrene, and 6.12 g of the α-methylstyrene / succinamic acid copolymer to a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0093] Example 4

[0094] (1) Add 17.7 g of α-methylstyrene, 14.7 g of sebacic anhydride, 80 g of butanone, 60 g of cyclohexane, and 0.3 g of BPO into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it three times with petroleum ether, and dry it to a constant weight in an oven at 50 °C to obtain the α-methylstyrene / sebacic anhydride copolymer;

[0095] (2) Take 20 g of the above-mentioned α-methylstyrene / sebacic anhydride copolymer, 10 g of ammonium bicarbonate, and stir at 50 °C for 12 hours to obtain the α-methylstyrene / sebacamide acid copolymer;

[0096] (3) Add 50 g of deionized water, 7.12 g of butyl acrylate, 16.89 g of acrylamide, and 9.60 g of α-methylstyrene / sebacamide acid copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 4 hours to obtain an emulsion.

[0097] Example 5

[0098] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isoamyl acetate, and 0.3 g of AIBN into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it three times with petroleum ether, and dry it to a constant weight in an oven at 50 °C to obtain the α-methylstyrene / maleic anhydride copolymer;

[0099] (2) Take 20 g of the above-mentioned α-methylstyrene / maleic anhydride copolymer and stir it at room temperature in an ammonia atmosphere for 12 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0100] (3) Add 50 g of deionized water, 20 g of ethanol, 13.37 g of ethyl acrylate, 10.44 g of methyl methacrylate, and 9.52 g of α-methylstyrene / maleamic acid copolymer into a 250 mL three-necked flask to obtain a clear and transparent solution, and then react at 90 °C without stirring for 2 hours to obtain an emulsion.

[0101] Example 6

[0102] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate, and 0.3 g of BPO into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it 3 times with petroleum ether, and dry it in an oven at 50 °C to a constant weight to obtain the α-methylstyrene / maleic anhydride copolymer;

[0103] (2) Take 20 g of the above α-methylstyrene / maleic anhydride copolymer, stir it at room temperature in an ammonia atmosphere for 12 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0104] (3) Add 50 g of deionized water, 18.89 g of methyl acrylate, 2.92 g of acrylonitrile, and 9.52 g of α-methylstyrene / maleamic acid copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0105] Example 7

[0106] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate, and 0.3 g of AIBN into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it 3 times with petroleum ether, and dry it in an oven at 50 °C to a constant weight to obtain the α-methylstyrene / maleic anhydride copolymer;

[0107] (2) Take 20 g of the above α-methylstyrene / maleic anhydride copolymer, stir it at room temperature in an ammonia atmosphere for 12 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0108] (3) Add 50 g of deionized water, 10.68 g of butyl acrylate, 25.03 g of vinyl acetate, and 14.28 g of α-methylstyrene / maleamic acid copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 4 hours to obtain an emulsion.

[0109] Example 8

[0110] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate and 0.3 g of AIBN to a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it 3 times with petroleum ether, and dry it to a constant weight in an oven at 50 °C to obtain the α-methylstyrene / maleamic acid copolymer;

[0111] (2) Take 20 g of the above α-methylstyrene / maleic anhydride copolymer and stir it at room temperature in an ammonia atmosphere for 12 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0112] (3) Add 50 g of deionized water, 20.05 g of butyl acrylate, 15.66 g of 2-ethoxyethyl acrylate, and 14.28 g of α-methylstyrene / maleamic acid copolymer to a 250 mL three-necked flask. First, stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0113] Example 9

[0114] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate and 0.3 g of AIBN to a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction is completed, separate the product, wash it 3 times with petroleum ether, and dry it to a constant weight in an oven at 50 °C to obtain the α-methylstyrene / maleamic acid copolymer;

[0115] (2) Take 20 g of the above α-methylstyrene / maleic anhydride copolymer and stir it at room temperature in an ammonia atmosphere for 12 hours to obtain the α-methylstyrene / maleamic acid copolymer;

[0116] (3) Add 50 g of deionized water, 28.34 g of butyl acrylate, 7.38 g of isobornyl acrylate, and 14.28 g of α-methylstyrene / maleamic acid copolymer to a 250 mL three-necked flask. First, stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0117] Example 10

[0118] (1) Add 17.7 g of α-methylstyrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate and 0.3 g of AIBN into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction, separate the product, wash it three times with petroleum ether, and dry it in an oven at 50 °C to constant weight to obtain the α-methylstyrene / maleic anhydride copolymer;

[0119] (2) Take 20 g of the above-mentioned α-methylstyrene / maleic anhydride copolymer, 12 g of ammonia water, and 100 g of deionized water, stir at room temperature for 12 hours, then add 100 g of acetone to precipitate the product, filter, and dry to obtain the α-methylstyrene / maleamate copolymer;

[0120] (3) Add 50 g of deionized water, 28.34 g of vinyl acetate, 7.38 g of methylstyrene, and 14.28 g of α-methylstyrene / maleamate copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 300 rpm for 2 hours to obtain an emulsion.

[0121] The properties of the obtained emulsion are shown in Table 1.

[0122] Comparative Example 1

[0123] Same as Example 1, except that α-methylstyrene is replaced with styrene. The specific method is as follows:

[0124] (1) Add 15.9 g of styrene, 14.7 g of maleic anhydride, 162 g of isopentyl acetate and 0.2 g of AIBN into a 250 mL round-bottom flask, dissolve them thoroughly, and then purge with nitrogen for 30 minutes. Place the round-bottom flask in an oil bath at 70 °C and react for 12 hours. After the reaction, separate the product, wash it three times with petroleum ether, and dry it in an oven at 50 °C to constant weight to obtain the styrene / maleic anhydride copolymer;

[0125] (2) Take 20 g of the above-mentioned styrene / maleic anhydride copolymer and stir it at room temperature for 16 hours in an ammonia atmosphere to obtain the styrene / maleamic acid copolymer;

[0126] (3) Add 50 g of deionized water, 8.59 g of butyl acrylate, 6.71 g of methyl methacrylate, and 6.12 g of styrene / maleamic acid copolymer into a 250 mL three-necked flask, first stir at 300 rpm for 10 minutes for pre-emulsification; then, under the protection of nitrogen, stir at 90 °C at 200 rpm for 4 hours, but polymerization did not occur and no emulsion was obtained.

[0127] Comparative Example 2

[0128] Same as Example 2, except that α-methylstyrene is replaced with styrene. The specific method is as follows:

[0129] 1) Add 15.9 g styrene, 14.7 g itaconic anhydride, 162 g toluene, and 0.3 g ABVN to a 250 mL round-bottom flask and dissolve thoroughly. Then, deoxygenate with nitrogen for 30 minutes. Place the round-bottom flask in a 50°C oil bath and react for 12 hours. After the reaction, isolate the product, wash three times with petroleum ether, and dry in a 50°C oven to constant weight to obtain a styrene / itaconic anhydride copolymer.

[0130] (2) 20 g of the above-mentioned α-methylstyrene / itaconic anhydride copolymer, 5 g of ammonia water, and 100 g of deionized water were taken, stirred at room temperature for 12 hours, and then 100 g of acetone was added to precipitate the product, filtered, and dried to obtain a styrene / itaconamide copolymer;

[0131] (3) 50 g of deionized water, 5 g of ethanol, 4.58 g of cyclohexyl acrylate, 10.73 g of methyl methacrylate, and 6.12 g of styrene / itaconamide copolymer were added to a 250 mL three-necked flask and stirred at 300 rpm for 20 minutes for pre-emulsification; then, under the protection of nitrogen, stirred at 300 rpm at 90°C for 4 hours. Polymerization did not occur and no emulsion was obtained.

[0132] The reasons why emulsion polymerization cannot proceed after α-methylstyrene is replaced by styrene are as follows:

[0133] Steric hindrance

[0134] α-methylstyrene has both a phenyl group and a methyl group at the α-carbon atom, creating significant steric hindrance. When α-methylstyrene is copolymerized with maleic anhydride, a small number of structures with two closely linked α-methylstyrene units are formed, accounting for approximately 2.7% of the total number of units. This unit exhibits significant steric hindrance and poor stability. Therefore, above a certain temperature, it breaks down, generating free radicals and initiating polymerization.

[0135] Styrene, on the other hand, has no C atom at the α position and has less steric hindrance. Therefore, the polymer chain of the styrene / maleic anhydride copolymer is stable. Under the emulsion polymerization temperature of 70°C-90°C of the present invention, the polymer chain will not break and will not generate free radicals, so it cannot initiate emulsion polymerization.

[0136] Table 1 Properties of emulsion

[0137]

[0138] Example 11

[0139] The emulsions prepared in Examples 7 - 9 were used for bonding plywood at room temperature, and their bonding strengths were tested. The wood panels used were poplar veneers with dimensions of 15 cm × 15 cm × 0.2 cm. Bonding was carried out at room temperature with a coating amount of 20 - 60 g / m 2 , and left to stand for 4 hours to cure. Then they were cut into splines of 2.5 cm × 10 cm. According to the method of GB / T 7124 - 2008, the bonding strengths of the samples were tested, and each sample was tested 6 times. The specific results are shown in Table 2.

[0140] Table 2 Gluing Strength of Plywood Bonded at Room Temperature

[0141] <![CDATA[Coating amount (g / m 2 )]]> 20 40 60 Example 7 1.01 MPa 1.67 MPa 2.01 MPa Example 8 1.60 MPa 3.40 MPa 3.67 MPa Example 9 0.90 MPa 1.52 MPa 2.00 MPa

[0142] Example 12

[0143] Hot - press bonding: In the case of Examples 4 - 7 with a coating amount of 20 - 60 g / m 2 , hot - press treatment was carried out at 180 °C, 1 MPa for 3 minutes to obtain plywood. According to the method of GB / T 9846 - 2015, it was cut into splines of 2.5 cm × 10 cm, and the splines were soaked in water at 63 °C for 3 hours, and then the gluing strength of the samples was tested immediately. Each sample was tested 6 times, and the results are shown in Table 3. It can be seen that after hot - press treatment, a stable and water - resistant bonding layer was formed between the adhesive and the wood, and the bonding strength could reach 2.80 MPa.

[0144] Table 3 Gluing Strength of Plywood after Hot - Pressing (Soaked in 63 °C Water Bath for 3 Hours)

[0145] <![CDATA[Coating amount (g / m 2 )]]> 20 40 60 Example 4 1.80 MPa 2.40 MPa 2.80 MPa Example 5 0.90 MPa 1.67 MPa 2.20 MPa Example 6 1.20 MPa 2.10 MPa 2.50 MPa Example 7 1.40 MPa 2.30 MPa 2.67 MPa

[0146] Example 13

[0147] Decorative papers were prepared using the emulsions obtained in Examples 1 - 4. First, the base paper of the decorative paper (plain paper with a weight of 80 g / m 2 , Hangzhou Tianyuan Chengda Decoration Materials Co., Ltd.) was soaked in the emulsion, and then dried in an oven at 70 °C for 10 minutes to remove moisture, obtaining a pre - cured decorative paper with a resin content of 100% of the paper mass. Then, through hot - press treatment at 180 °C, 1 MPa for 3 minutes, the decorative paper was tightly bonded to the surface of the plywood. According to GB / T 17657 - 2013, its relevant properties were tested, and the results are shown in Table 4. It can be seen that all properties are far higher than the requirements of the national standard.

[0148] Table 4 Properties of Decorative Papers

[0149] Surface gluing strength Wear resistance Scratch resistance Example 1 0.77 MPa 26.9 mg / 100 r No obvious scratches Example 2 0.82 MPa 28.3 mg / 100 r No obvious scratches Example 3 1.08 MPa 25.3 mg / 100 r No obvious scratches Example 4 1.00 MPa 26.3 mg / 100 r No obvious scratches

[0150] Without wishing to be bound by any theory, it is believed that the amide groups on the polymer in the binder of the present invention and the carboxyl groups can dehydrate to form imide groups under pressing conditions, and the carboxyl groups can also dehydrate to form anhydride groups. The resulting anhydride groups can react with the hydroxyl groups on the lignocellulosic material to form esters, which helps to improve the mechanical properties and water resistance of the resulting wood-based panel.

[0151] The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An adhesive, characterized in that, The adhesive comprises a macroinitiator, one or more vinyl monomers, and a solvent; The macroinitiator has a hydrophilic unit and an α-methylstyrene structural unit; the hydrophilic unit is a structural unit containing at least one amide group and a carboxyl group and / or its ammonium salt; The macroinitiator is obtained by reacting copolymer A with ammonia, and the copolymer A is a copolymer of α-methylstyrene and a monomer having a carbon-carbon unsaturated double bond and an acid anhydride group; The monomer having a carbon-carbon unsaturated double bond and an acid anhydride group is selected from monoethylenically unsaturated dicarboxylic anhydrides having 4 to 8 carbon atoms.

2. The adhesive according to claim 1, wherein, The vinyl monomer is selected from at least one of the following monomers: monoethylenically unsaturated C3-C8 monocarboxylic acids, C1-C 10 alkyl esters of monoethylenically unsaturated C3-C8 monocarboxylic acids, amides of monoethylenically unsaturated C3-C8 monocarboxylic acids, vinyl alkyl ethers having a C1-C8 alkyl group, C1-C 20 vinyl esters of carboxylic acids, methoxypolyethylene glycol (meth)acrylate, glycidyl (meth)acrylate, ethylenically unsaturated monomers containing a hydroxyl group, styrene, styrene substituted with one or more substituents selected from alkyl, alkoxy and halogen, vinylpyrrolidone, (meth)acrylonitrile, N-vinylformamide or vinylsiloxane monomers; The solvent is selected from one or more of water, alcohols, ketones, dioxane, tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide.

3. The adhesive according to claim 1, wherein The dosage of the vinyl monomer is 10-120% of the mass of the solvent; The dosage of the macroinitiator is 5-60% of the mass of the vinyl monomer.

4. A method for preparing the adhesive according to any one of claims 1-3, characterized in that, Comprising the following steps: a) Providing a reaction mixture, the reaction mixture comprising a macroinitiator, one or more vinyl monomers, and a solvent; b) Flushing the reaction mixture with an inert gas, and then polymerizing the reaction mixture by free radical polymerization to obtain an adhesive.

5. The preparation method of the adhesive according to claim 4, characterized in that, The reaction temperature of the free radical polymerization is 70-100°C, and the reaction time is 0.5-8 hours.

6. Use of the adhesive according to any one of claims 1-3 in the preparation of wood-based panels, decorative papers, fabrics or coatings, characterized in that, Relative to the total mass of the wood-based panel, decorative paper, cloth, or coating, the dosage of the adhesive is 1-200% in terms of the solid content.

7. A wood-based panel, characterized in that, Formed from lignocellulosic material and the adhesive according to any one of claims 1-3.

8. A decorative paper, characterized in that, Formed from paper and the adhesive according to any one of claims 1-3.

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