A light-curing PVAc-based water-based wood coating, preparation method and efficient coating method

Abstract

The present invention relates to a photocurable PVAc-based water-based wood coating, a preparation method and an efficient coating method, and belongs to the technical field of water-based wood coatings. In order to solve the problems of slow film-forming speed and low coating efficiency of existing water-based wood coatings, the present invention provides a photocurable PVAc-based water-based wood coating, the raw materials of which include core layer monomers, shell layer monomers a, shell layer monomers b, grafted monomers, thiol monomers, active monomers, etc. On the basis of the preparation process of PVAc / PS core-shell emulsion, the present invention introduces thiol groups into the shell layer of latex particles, and enables the prepared water-based emulsion coating to be UV-cured by grafting highly active reactive groups onto the surface of the core-shell latex particles. When applied to topcoat finishing and wood of different substrates, UV curing can be achieved within 30 seconds and has high adhesion and cross-linking properties, which can reduce the number of coatings, significantly improve the coating efficiency of water-based coatings, and expand the application range of water-based photocurable coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterborne wood coatings, and in particular relates to a light-curing PVAc-based waterborne wood coating, a preparation method and an efficient coating method. Background Art

[0002] Water-based paints, using water as a solvent, offer advantages such as energy conservation, environmental protection, and the absence of volatile organic compounds (VOCs). With growing environmental awareness and increasingly stringent regulations on VOCs, environmentally friendly water-based paints have become a hot topic in research and application. However, the slow film-forming rate of water-based paints results in low coating efficiency during daily use, significantly limiting their application in areas such as interior decoration and wood coatings.

[0003] Currently, the slow film-forming speed of water-based paints is typically addressed by increasing the drying temperature. However, excessively high film-forming temperatures can cause cracking of the coating, resulting in high energy consumption and significantly reduced coating performance. Furthermore, to ensure film performance, multiple coating passes are often used in the production process, severely reducing coating efficiency. Therefore, the development of highly efficient and high-performance water-based wood coatings is urgently needed. Summary of the Invention

[0004] In order to solve the problems of slow film-forming speed and low coating efficiency of existing water-based wood coatings, the present invention provides a light-curing PVAc-based water-based wood coating, a preparation method and an efficient coating method.

[0005] The technical solution of the present invention:

[0006] A light-curing PVAc-based water-based wood coating comprises the following raw materials in parts by weight:

[0007] 50-70 parts of core layer monomer, 30-50 parts of shell layer monomer a, 20-32 parts of shell layer monomer b, 1.5-2.5 parts of graft monomer, 80-280 parts of thiol monomer, 20-420 parts of active monomer, 4.5-10 parts of emulsifier, 0.3-0.4 parts of initiator, 0.5-1.5 parts of pH buffer and 125-150 parts of deionized water.

[0008] Furthermore, the core layer monomer is vinyl acetate, the shell layer monomer a is styrene, the shell layer monomer b is dipentene or 1-allylcyclohexene, the graft monomer is acrylonitrile, the thiol monomer is trimethylolpropane tris-3-mercaptopropionate, the active monomer is hexanediol diacrylate, dipropylene glycol diacrylate, triol dimethacrylate or trimethylolpropane trimethacrylate; the emulsifier is a mixture of equal masses of PCA507 emulsifier and PCA078 emulsifier, the initiator is ammonium persulfate, and the pH buffer is sodium bicarbonate.

[0009] A method for preparing a light-curing PVAc-based water-based wood coating comprises the following steps:

[0010] Step 1: Prepare the nuclear seed emulsion:

[0011] Mixing deionized water, an emulsifier, and a pH buffer solution to form a pre-emulsified solution, and sequentially adding a portion of the core layer monomer and a portion of the initiator to the obtained pre-emulsified solution to obtain a core seed emulsion;

[0012] Step 2: Preparation of core-shell structure emulsion:

[0013] The remaining core layer monomer, the remaining initiator, the grafting monomer, the shell layer monomer a, the shell layer monomer b and the thiol monomer are sequentially added dropwise to the core seed emulsion obtained in step 1, and after the reaction, a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles is obtained;

[0014] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0015] The pre-emulsified active monomer is added dropwise to the core-shell structure emulsion system obtained in step 2 to obtain a light-cured PVAc-based water-based wood coating.

[0016] Furthermore, the deionized water, emulsifier and pH buffer in step 1 are pre-emulsified at 60° C. and a stirring rate of 250 r / min for 30 minutes; the mass fraction of the partial core layer monomer is at least 9 parts, and the partial initiator is prepared by dissolving 0.2 to 0.25 parts of initiator in 7.5 to 9.5 parts of deionized water.

[0017] Furthermore, in step 1, part of the core layer monomer is first added to the obtained pre-emulsified system, and stirring and emulsifying is continued for 30 minutes. Then part of the initiator is added and the temperature is raised to 65° C. After the solution turns slightly emulsified blue and the reflux of the condenser disappears, the temperature is raised to 80° C. to obtain a core seed emulsion.

[0018] Furthermore, in step 2, the dropping rate of the remaining core layer monomer is 0.4-0.6 ml / min, and the remaining initiator is added 30 minutes after the start of the dropping of the remaining core layer monomer; the dropping rate of the remaining initiator is 0.1-0.2 ml / min.

[0019] Furthermore, after the remaining initiator in step 2 is added dropwise, the grafting monomer is added dropwise to the system at a rate of 1 ml / min; immediately after the grafting monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min, and after 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min; after the shell monomer a is added dropwise, the temperature is raised to 85° C. and kept warm for 30 minutes, and then the shell monomer b is added dropwise to the system at a rate of 0.1 to 1.0 ml / min, and after the addition is completed, the temperature is kept warm for 30 minutes; then the system is heated to 90 to 100° C., and the thiol monomer is added dropwise to the system at a rate of 0.1 to 0.5 ml / min, and after the addition is completed, the temperature is kept warm for 30 minutes.

[0020] Furthermore, the pre-emulsified active monomer in step 3 is prepared by mixing the active monomer and water in a mass ratio of 7:3, adding 1% of the total mass of emulsifier OP-10 and homogenizing and emulsifying.

[0021] Furthermore, in step 3, when the temperature of the core-shell structure emulsion system drops to 40-70° C., the pre-emulsified active monomer is added at a dropwise acceleration rate of 0.1-0.5 ml / min.

[0022] A high-efficiency coating method for a light-curing PVAc-based waterborne wood coating comprises applying the light-curing PVAc-based waterborne wood coating according to claim 1 or 2 to a wood surface and curing the coating under conditions of ultraviolet light with a wavelength of 395 nm and an irradiation distance of 15 cm.

[0023] Beneficial effects of the present invention:

[0024] Based on the preparation process of PVAc / PS (polystyrene) core-shell emulsion, the present invention introduces thiol groups into the shell layer of latex particles to prepare a light-curable PVAc-based core-shell emulsion. By grafting highly active reactive groups onto the surface of the core-shell latex particles, the prepared water-based emulsion coating can be ultraviolet-cured. When applied to primer coating for wood products, it can be rapidly light-cured within 10 seconds, meeting the requirements of conventional coating processes.

[0025] When applied to topcoat finishes and wood substrates, the UV-curable PVAc-based waterborne wood coating prepared by this invention can achieve UV curing within 30 seconds. Furthermore, the prepared emulsion exhibits high adhesion and crosslinking properties, which not only improve the mechanical properties of the emulsion paint film but also enhance its adhesion to the substrate. This can significantly reduce the number of times the emulsion coating needs to be applied to the substrate, significantly improving the coating efficiency of waterborne coatings and broadening the application range of waterborne UV-curable coatings.

[0026] The light-curing PVAc-based water-based wood coating prepared by the present invention has a simple production process, easy-to-control reaction conditions, and does not change the conventional emulsion polymerization industry. At the same time, the emulsion has excellent stability, and the performance of the prepared wood paint film can meet the use requirements.

[0027] The light-curable PVAc-based aqueous emulsion prepared by the present invention uses water as a solvent, has no volatile organic compounds, reduces the release of VOCs, has environmentally friendly characteristics, and can alleviate environmental pollution problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 From left to right are SEM images of thiolated PVAc-based core-shell latex particles with different TMPMP contents prepared in step 2 of Example 8, Example 11, and Example 12;

[0029] Figure 2 This is a Fourier transform infrared spectrum of the latex particles grafted with thiol monomer in step 2 of Example 8;

[0030] Figure 3 DSC curves of thiolated PVAc-based core-shell latex particles with different TMPMP contents prepared in step 2 of Example 8, Example 11, and Example 12;

[0031] Figure 4 A comparison chart of the photocuring time of photocurable PVAc-based waterborne wood coatings with different HDDA contents prepared in Examples 1-5 on wood blocks;

[0032] Figure 5 for Figure 4 The corresponding photos of the wood blocks after the coatings are cured are Examples 1-5 from left to right.

[0033] Figure 6 A comparison of the photocuring time of the photocurable PVAc-based waterborne wood coatings with different HDDA contents prepared in Examples 1-5 on primed wood blocks;

[0034] Figure 7 A comparison chart of the photocuring time of photocurable PVAc-based waterborne wood coatings with different TMPTA contents prepared in Examples 6-10 on wood blocks;

[0035] Figure 8 This is a comparison of the photocuring time of the photocurable PVAc-based waterborne wood coatings with different TMPTA contents prepared in Examples 6-10 on primed wood blocks. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the scope of protection of the present invention. The process equipment or devices not specifically noted in the following examples are all conventional equipment or devices in the art. Unless otherwise specified, the raw materials used in the examples of the present invention can be obtained commercially; unless otherwise specified, the technical means used in the examples of the present invention are all conventional means well known to those skilled in the art.

[0037] Example 1

[0038] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer HDDA to the thiol monomer TMPMP is 0.5:1.

[0039] The raw materials and weight parts used in this embodiment are as follows:

[0040] Core layer monomer vinyl acetate PVAc 60 parts,

[0041] Shell monomer a styrene 40 parts,

[0042] Shell monomer b: 32 parts of dipentene,

[0043] 2 parts of grafting monomer acrylonitrile AN,

[0044] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0045] Active monomer 1,6-hexanediol diacrylate HDDA 26 parts,

[0046] 10 parts of emulsifier,

[0047] Initiator ammonium persulfate 0.35 parts,

[0048] pH buffer sodium bicarbonate 1 part,

[0049] and 125 parts of deionized water.

[0050] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0051] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0052] Step 1: Prepare the nuclear seed emulsion:

[0053] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0054] Step 2: Preparation of core-shell structure emulsion:

[0055] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0056] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0057] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0058] The active monomer hexanediol diacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 drops to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a drop rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0059] Example 2

[0060] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the reactive monomer HDDA to the thiol monomer TMPMP is 1:1.

[0061] The raw materials and weight parts used in this embodiment are as follows:

[0062] Core layer monomer vinyl acetate PVAc 60 parts,

[0063] Shell monomer a styrene 40 parts,

[0064] Shell monomer b: 32 parts of dipentene,

[0065] 2 parts of grafting monomer acrylonitrile AN,

[0066] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0067] Active monomer hexanediol diacrylate HDDA 52 parts,

[0068] 10 parts of emulsifier,

[0069] Initiator ammonium persulfate 0.35 parts,

[0070] pH buffer sodium bicarbonate 1 part,

[0071] and 125 parts of deionized water.

[0072] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0073] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0074] Step 1: Prepare the nuclear seed emulsion:

[0075] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0076] Step 2: Preparation of core-shell structure emulsion:

[0077] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0078] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0079] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0080] The active monomer hexanediol diacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 drops to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a drop rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0081] Example 3

[0082] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer HDDA to the thiol monomer TMPMP is 2:1.

[0083] The raw materials and weight parts used in this embodiment are as follows:

[0084] Core layer monomer vinyl acetate PVAc 60 parts,

[0085] Shell monomer a styrene 40 parts,

[0086] Shell monomer b: 32 parts of dipentene,

[0087] 2 parts of grafting monomer acrylonitrile AN,

[0088] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0089] Active monomer hexanediol diacrylate HDDA 104 parts,

[0090] 10 parts of emulsifier,

[0091] Initiator ammonium persulfate 0.35 parts,

[0092] pH buffer sodium bicarbonate 1 part,

[0093] and 125 parts of deionized water.

[0094] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0095] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0096] Step 1: Prepare the nuclear seed emulsion:

[0097] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0098] Step 2: Preparation of core-shell structure emulsion:

[0099] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0100] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0101] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0102] The active monomer hexanediol diacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 drops to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a drop rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0103] Example 4

[0104] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer HDDA to the thiol monomer TMPMP is 3:1.

[0105] The raw materials and weight parts used in this embodiment are as follows:

[0106] Core layer monomer vinyl acetate PVAc 60 parts,

[0107] Shell monomer a styrene 40 parts,

[0108] Shell monomer b: 32 parts of dipentene,

[0109] 2 parts of grafting monomer acrylonitrile AN,

[0110] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0111] Active monomer hexanediol diacrylate HDDA 156 parts,

[0112] 10 parts of emulsifier,

[0113] Initiator ammonium persulfate 0.35 parts,

[0114] pH buffer sodium bicarbonate 1 part,

[0115] and 125 parts of deionized water.

[0116] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0117] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0118] Step 1: Prepare the nuclear seed emulsion:

[0119] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0120] Step 2: Preparation of core-shell structure emulsion:

[0121] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0122] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0123] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0124] The active monomer hexanediol diacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 drops to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a drop rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0125] Example 5

[0126] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer HDDA to the thiol monomer TMPMP is 4:1.

[0127] The raw materials and weight parts used in this embodiment are as follows:

[0128] Core layer monomer vinyl acetate PVAc 60 parts,

[0129] Shell monomer a styrene 40 parts,

[0130] Shell monomer b: 32 parts of dipentene,

[0131] 2 parts of grafting monomer acrylonitrile AN,

[0132] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0133] Active monomer hexanediol diacrylate HDDA 208 parts,

[0134] 10 parts of emulsifier,

[0135] Initiator ammonium persulfate 0.35 parts,

[0136] pH buffer sodium bicarbonate 1 part,

[0137] and 125 parts of deionized water.

[0138] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0139] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0140] Step 1: Prepare the nuclear seed emulsion:

[0141] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0142] Step 2: Preparation of core-shell structure emulsion:

[0143] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0144] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0145] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0146] The active monomer hexanediol diacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 drops to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a drop rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0147] Example 6

[0148] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 0.5:1.

[0149] The raw materials and weight parts used in this embodiment are as follows:

[0150] Core layer monomer vinyl acetate PVAc 60 parts,

[0151] Shell monomer a styrene 40 parts,

[0152] Shell monomer b: 32 parts of dipentene,

[0153] 2 parts of grafting monomer acrylonitrile AN,

[0154] Thiol monomer trimethylolpropane tris-3-mercaptopropionate TMPMP 93 parts,

[0155] Active monomer trimethylolpropane triacrylate TMPTA 34.7 parts,

[0156] 10 parts of emulsifier,

[0157] Initiator ammonium persulfate 0.35 parts,

[0158] pH buffer sodium bicarbonate 1 part,

[0159] and 125 parts of deionized water.

[0160] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0161] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0162] Step 1: Prepare the nuclear seed emulsion:

[0163] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0164] Step 2: Preparation of core-shell structure emulsion:

[0165] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0166] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0167] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0168] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0169] Example 7

[0170] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the reactive monomer HDDA to the thiol monomer TMPMP is 1:1.

[0171] The raw materials and weight parts used in this embodiment are as follows:

[0172] Core layer monomer vinyl acetate PVAc 60 parts,

[0173] Shell monomer a styrene 40 parts,

[0174] Shell monomer b: 32 parts of dipentene,

[0175] 2 parts of grafting monomer acrylonitrile AN,

[0176] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0177] Active monomer trimethylolpropane triacrylate TMPTA 69.5 parts,

[0178] 10 parts of emulsifier,

[0179] Initiator ammonium persulfate 0.35 parts,

[0180] pH buffer sodium bicarbonate 1 part,

[0181] and 125 parts of deionized water.

[0182] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0183] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0184] Step 1: Prepare the nuclear seed emulsion:

[0185] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0186] Step 2: Preparation of core-shell structure emulsion:

[0187] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0188] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0189] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0190] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0191] Example 8

[0192] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 2:1.

[0193] The raw materials and weight parts used in this embodiment are as follows:

[0194] Core layer monomer vinyl acetate PVAc 60 parts,

[0195] Shell monomer a styrene 40 parts,

[0196] Shell monomer b: 32 parts of dipentene,

[0197] 2 parts of grafting monomer acrylonitrile AN,

[0198] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0199] Active monomer trimethylolpropane triacrylate TMPTA 139 parts,

[0200] 10 parts of emulsifier,

[0201] Initiator ammonium persulfate 0.35 parts,

[0202] pH buffer sodium bicarbonate 1 part,

[0203] and 125 parts of deionized water.

[0204] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0205] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0206] Step 1: Prepare the nuclear seed emulsion:

[0207] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0208] Step 2: Preparation of core-shell structure emulsion:

[0209] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0210] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0211] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0212] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0213] Example 9

[0214] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 3:1.

[0215] The raw materials and weight parts used in this embodiment are as follows:

[0216] Core layer monomer vinyl acetate PVAc 60 parts,

[0217] Shell monomer a styrene 40 parts,

[0218] Shell monomer b: 32 parts of dipentene,

[0219] 2 parts of grafting monomer acrylonitrile AN,

[0220] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0221] Active monomer trimethylolpropane triacrylate TMPTA 208 parts,

[0222] 10 parts of emulsifier,

[0223] Initiator ammonium persulfate 0.35 parts,

[0224] pH buffer sodium bicarbonate 1 part,

[0225] and 125 parts of deionized water.

[0226] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0227] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0228] Step 1: Prepare the nuclear seed emulsion:

[0229] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0230] Step 2: Preparation of core-shell structure emulsion:

[0231] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0232] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0233] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0234] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0235] Example 10

[0236] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 1:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 4:1.

[0237] The raw materials and weight parts used in this embodiment are as follows:

[0238] Core layer monomer vinyl acetate PVAc 60 parts,

[0239] Shell monomer a styrene 40 parts,

[0240] Shell monomer b: 32 parts of dipentene,

[0241] 2 parts of grafting monomer acrylonitrile AN,

[0242] 93 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0243] Active monomer trimethylolpropane triacrylate TMPTA 278 parts,

[0244] 10 parts of emulsifier,

[0245] Initiator ammonium persulfate 0.35 parts,

[0246] pH buffer sodium bicarbonate 1 part,

[0247] and 125 parts of deionized water.

[0248] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0249] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0250] Step 1: Prepare the nuclear seed emulsion:

[0251] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0252] Step 2: Preparation of core-shell structure emulsion:

[0253] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0254] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0255] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0256] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0257] Example 11

[0258] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 2:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 2:1.

[0259] The raw materials and weight parts used in this embodiment are as follows:

[0260] Core layer monomer vinyl acetate PVAc 60 parts,

[0261] Shell monomer a styrene 40 parts,

[0262] Shell monomer b: 32 parts of dipentene,

[0263] 2 parts of grafting monomer acrylonitrile AN,

[0264] 186 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0265] Active monomer trimethylolpropane triacrylate TMPTA 278 parts,

[0266] 10 parts of emulsifier,

[0267] Initiator ammonium persulfate 0.35 parts,

[0268] pH buffer sodium bicarbonate 1 part,

[0269] and 125 parts of deionized water.

[0270] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0271] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0272] Step 1: Prepare the nuclear seed emulsion:

[0273] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0274] Step 2: Preparation of core-shell structure emulsion:

[0275] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0276] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0277] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0278] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0279] Example 12

[0280] This embodiment provides a photocurable PVAc-based waterborne wood coating and a preparation method thereof. In this embodiment, the molar mass ratio of the thiol monomer TMPMP to styrene is 3:1; the molar mass ratio of the active monomer TMPTA to the thiol monomer TMPMP is 2:1.

[0281] The raw materials and weight parts used in this embodiment are as follows:

[0282] Core layer monomer vinyl acetate PVAc 60 parts,

[0283] Shell monomer a styrene 40 parts,

[0284] Shell monomer b: 32 parts of dipentene,

[0285] 2 parts of grafting monomer acrylonitrile AN,

[0286] 279 parts of mercaptan monomer trimethylolpropane tris-3-mercaptopropionate TMPMP,

[0287] Active monomer trimethylolpropane triacrylate TMPTA 417 parts,

[0288] 10 parts of emulsifier,

[0289] Initiator ammonium persulfate 0.35 parts,

[0290] pH buffer sodium bicarbonate 1 part

[0291] and 125 parts of deionized water.

[0292] The emulsifier is a mixture of PCA507 emulsifier and PCA078 emulsifier mixed in equal amounts.

[0293] The preparation method of the light-curing PVAc-based water-based wood coating provided in this embodiment comprises the following steps:

[0294] Step 1: Prepare the nuclear seed emulsion:

[0295] Deionized water, an emulsifier, and a pH buffer solution were mixed uniformly in a four-necked flask, and pre-emulsified for 30 min in a water bath at 60° C. and a stirring rate of 250 r / min. 11 parts of a core layer monomer were added to the obtained pre-emulsified system, and the mixture was stirred and emulsified for 30 min. Then, an initiator prepared by 0.25 parts of ammonium persulfate and 9.3 parts of deionized water was added. The temperature was raised to 65° C., and after the solution turned slightly emulsified blue and the reflux on the condenser disappeared, the temperature was raised to 80° C. to obtain a core seed emulsion.

[0296] Step 2: Preparation of core-shell structure emulsion:

[0297] After the temperature of the reaction system obtained in step 1 stabilizes to 80° C., the remaining core layer monomer is added dropwise to the system at a rate of 0.4 to 0.6 ml / min. 30 minutes after the start of the addition of the remaining core layer monomer, the remaining initiator is added dropwise to the system at a rate of 0.1 to 0.2 ml / min. The remaining initiator is prepared by 0.1 parts of ammonium persulfate and 15.6 parts of deionized water;

[0298] After the remaining core monomer and the remaining initiator are all added, the graft monomer is added dropwise to the system at a rate of 1 ml / min. Immediately after the graft monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min. After 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min. After the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes. Then, the shell monomer b is added dropwise to the system at a rate of 0.5 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes. Then, the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 ml / min. After the addition is completed, the temperature is kept warm for 30 minutes to obtain a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles.

[0299] Step 3: Preparation of light-curing PVAc-based waterborne wood coating:

[0300] The active monomer trimethylolpropane triacrylate and water are mixed in a mass ratio of 7:3, and 1% of the total mass of emulsifier OP-10 is added for homogeneous emulsification to obtain an emulsified active monomer; after the temperature of the core-shell structure emulsion system obtained in step 2 is reduced to 40-70°C, the pre-emulsified active monomer is added dropwise to the system at a dropping rate of 0.5 ml / min to obtain a light-curable PVAc-based waterborne wood coating.

[0301] Sample characterization:

[0302] Figure 1 From left to right are the SEM images of thiolated PVAc-based core-shell latex particles with different TMPMP contents prepared in step 2 of Example 8, Example 11 and Example 12; it can be seen from the figure that PS spherical particles are distributed on the surface of the PVAc core to form a core-shell structure similar to a "strawberry shape". Comparing the three figures, it can be seen that the uniformity of the prepared latex particles and the size of the surface protrusions are similar, indicating that the change in the TMPMP monomer content does not affect the morphology of the latex particles. This is because the PVAc-based core-shell latex particles prepared under different TMPMP contents ensure the consistency of the core-shell ratio and the AN content. Under the same preparation process, the small molecule TMPMP grafted on the shell layer does not cause too much influence on the morphology of the latex particles. Therefore, the core-shell structure of the PVAc-based core-shell latex particles prepared under different TMPMP contents remains basically consistent.

[0303] Figure 2 The Fourier transform infrared spectra of the latex particles grafted with thiol monomers in step 2 of Example 8 are shown. In the figure, the double-bond functionalized core-shell latex particles are the latex particles before the grafting of thiol monomers; the thiolated core-shell latex particles are the latex particles after the grafting of monomers. It can be seen from the figure that both curves are at 1740 cm -1 The C=O stretching vibration peak of the ester group appears at 1237 cm -1 and 1026cm -1 The peak at 1375cm is the stretching vibration absorption peak of COC in the ester group. -1 The -CH3 symmetric deformation vibration absorption peak appears at 2926cm -1 At 3082cm -1 、3060cm -1 、3026cm -1 The stretching vibration absorption peak of CH on the benzene ring skeleton appears at 1602cm -1 、1583cm -1 、1493cm -1 The characteristic peak at 758cm is the bending vibration absorption peak of the C=C double bond on the benzene ring skeleton. -1 、698cm-1 The out-of-plane bending vibration absorption peak of CH on the monosubstituted benzene ring skeleton appears at 2242 cm -1 The characteristic absorption peak of the CN triple bond on AN appears at 2300 cm, indicating that the grafted monomer AN exists in the latex particles. In addition, comparing the two curves, the infrared curve of the thiolated emulsion is -1 A distinct characteristic peak appears at , which is the characteristic absorption peak of -SH. A detailed analysis of the various groups in the latex particles' infrared spectra reveals the presence of characteristic absorption peaks of vinyl acetate (VAc), acrylonitrile (AN), styrene (St), and DTT structures in the polymer. Infrared results indicate that, based on the construction of PVAc core-shell latex particles, thiols were successfully grafted onto the surface of the latex particle shell.

[0304] Figure 3 These are the DSC curves of the thiolated PVAc-based core-shell latex particles with different TMPMP contents prepared in step 2 of Example 8, Example 11, and Example 12. It can be seen that two relatively obvious glass transition temperatures appear in the DSC curves corresponding to the TMPMP content, namely the glass transition temperature of PVAc (Tg=32°C) and the glass transition temperature of PS (Tg=106°C), indicating that the thiolated core-shell latex particles prepared with different TMPMP contents all have a phase separation structure.

[0305] Figure 4 A comparison chart of the photocuring time of photocurable PVAc-based waterborne wood coatings with different HDDA contents prepared in Examples 1-5 on wood blocks; Figure 5 for Figure 4 The corresponding photos of the wood blocks after the coatings are cured are Examples 1-5 from left to right.

[0306] from Figure 4 As can be seen, when the ratio of active monomers HDDA to TMPMP is 0.5:1, the emulsion is completely cured in 37 seconds under ultraviolet light (UV wavelength 395nm, irradiation distance 15cm). When the ratio of HDDA to TMPMP is 1:1, the aqueous emulsion is completely cured after 31 seconds. As the active monomer content increases, when the ratio of HDDA to TMPMP is 2:1, the curing time of the aqueous emulsion is accelerated by 9.6%. When the ratio of HDDA to TMPMP is 3:1, the aqueous emulsion is completely cured in only 18 seconds. However, when the ratio of HDDA to TMPMP is increased to 4:1, the curing time of the aqueous emulsion increases, indicating that the ratio of active monomers HDDA to TMPMP is 3:1.

[0307] To test the curing rate of water-based emulsions on different substrate woods, thiolated PVAc-based water-based emulsions with different HDDA contents were coated on primed wood blocks for light curing tests; Figure 6 This is a comparison of the photocuring time of the photocurable PVAc-based waterborne wood coatings with different HDDA contents prepared in Examples 1-5 on primed wood blocks.

[0308] As shown in the figure, when the HDDA:TMPMP ratio was 0.5:1, the emulsion was fully cured in 52 seconds under UV light (UV wavelength 395nm, irradiation distance 15cm), indicating that thiolated aqueous emulsions can also be used in primed wood finishes. When the HDDA:TMPMP ratio was 1:1, the emulsion was fully cured in 48 seconds. With increasing reactive monomer content, the curing time of the aqueous emulsion increased slightly when the HDDA:TMPMP ratio was 2:1 and 3:1. The optimal curing rate was achieved at a ratio of 4:1, with complete cure in just 36 seconds. This demonstrates that thiolated aqueous emulsions also exhibit excellent UV curing efficiency when used in primed wood finishes.

[0309] The surface coating test was carried out on the cured wood blocks. The film properties of the thiolated PVAc-based water-based emulsion wood coatings prepared with different ratios of HDDA to TMPMP are shown in Table 1.

[0310] Table 1 Wood coating film properties

[0311]

[0312] It can be seen from Table 1 that with the increase of the active monomer HDDA content, the gloss of the thiolated PVAc-based water-based emulsion paint film gradually increases. When the ratio of HDDA to TMPMP is 0.5:1, the gloss of the paint film is 8.7°. As the amount of HDDA added increases, when the ratio of HDDA to TMPMP is 4:1, it reaches a maximum of 11.8°.

[0313] When the ratio of HDDA to TMPMP is 0.5:1, the roughness of the thiolated water-based emulsion paint film is 4.58 μm. As the HDDA content increases, the roughness of the paint film decreases to 3.35 μm. As the content of the active monomer HDDA further increases, the roughness of the liquid paint film becomes lower, until when the ratio of HDDA to TMPMP is 4:1, the roughness of the paint film reaches a minimum value of 2.87 μm; when the HDDA content is low, the pencil hardness of the thiolated PVAc-based water-based emulsion wood coating film is relatively low, only 3H. When the ratio of HDDA to TMPMP reaches 1:1, the pencil hardness of the paint film increases to 4H, and as the ratio of HDDA to TMPMP increases until it reaches 4:1, the pencil hardness of the paint film remains at a maximum value of 4H.

[0314] Figure 7 This figure compares the curing time of photocurable PVAc-based waterborne wood coatings with different TMPTA contents prepared in Examples 6-10 on wood blocks. As can be seen from the figure, when the ratio of TMPTA to TMPMP is 0.5:1, the emulsion can be completely cured in 25 seconds under ultraviolet light (ultraviolet light wavelength 395nm, irradiation distance 15cm), indicating that the ultraviolet curing efficiency of the thiolated waterborne emulsion is very high when used for wood finishing. When the ratio of TMPTA to TMPMP is 1:1, the photocuring rate of the aqueous emulsion increases by 32%, and the emulsion is completely cured in only 17 seconds; with the increase of active monomer content, when the ratio of TMPTA to TMPMP is 2:1, the curing time of the aqueous emulsion is accelerated by another 6 seconds. When the ratio of TMPTA to TMPMP is 3:1, the aqueous emulsion can be completely cured in only 8.6 seconds. However, when the ratio of TMPTA to TMPMP continues to increase to 4:1, the curing time of the aqueous emulsion increases instead, indicating that the ratio of TMPTA to TMPMP is 3:1 is the optimal ratio of the aqueous emulsion.

[0315] Figure 8 A comparative graph shows the curing time of photocurable PVAc-based waterborne wood coatings prepared in Examples 6-10 with varying TMPTA contents on primed wood. The graph shows that when the TMPTA:TMPMP ratio was 0.5:1, the emulsion fully cured in 37 seconds under UV light (UV wavelength 395 nm, irradiation distance 15 cm), demonstrating that thiolated waterborne emulsions can also be used for primed wood finishes. A waterborne emulsion with a TMPTA:TMPMP ratio of 1:1 cured slightly faster, reaching full cure in 35 seconds. With increasing reactive monomer content, the curing speed of the waterborne emulsion increased by 17% when the TMPTA:TMPMP ratio was 2:1. A TMPTA:TMPMP ratio of 3:1 achieved the fastest curing rate, requiring only 28 seconds. A TMPTA:TMPMP ratio of 4:1 also exhibited a slight increase in curing speed. The comprehensive light curing time of the water-based emulsion at various ratios shows that the thiolated water-based emulsion also exhibits excellent UV curing efficiency when used for wood coating with primer.

[0316] The surface coating test was carried out on the cured wood blocks. The film properties of the thiolated PVAc-based water-based emulsion wood coatings prepared with different ratios of TMPTA to TMPMP are shown in Table 2.

[0317] Table 2 Wood coating film properties

[0318]

[0319] It can be seen from Table 2 that with the increase of the ratio of active monomers TMPTA to TMPMP, the gloss of the thiolated PVAc-based water-based emulsion paint film gradually increases. When the ratio of TMPTA to TMPMP is 0.5:1, the gloss of the paint film is 8.1°. As the ratio of TMPTA to TMPMP increases to 1:1, the gloss of the paint film increases significantly to 8.5°. When the ratio of TMPTA to TMPMP is further increased to 2:1, the gloss increases significantly to 26.8°. When the ratio of TMPTA to TMPMP is further increased, the gloss decreases again. When the ratio of TMPTA to TMPMP is 0.5:1, the gloss of the paint film is 8.1°. :1, the roughness of the paint film is 3.92μm. As the ratio of TMPTA to TMPMP increases to 1:1, the roughness of the paint film decreases to 2.5μm. As the ratio of active monomers TMPTA and TMPMP continues to increase, the roughness of the liquid paint film becomes lower. When the ratio of TMPTA to TMPMP is further increased, the roughness increases instead. Therefore, when the ratio of active monomers TMPTA to TMPMP is 2:1, the roughness of the paint film reaches the minimum value of 1.63μm. Under different TMPTA and TMPMP ratios, the pencil hardness of the thiolated PVAc-based water-based emulsion wood coating film is 4H, showing excellent hardness.

Claims

1. A light-curing PVAc-based water-based wood coating, characterized in that: The invention comprises the following raw materials in parts by weight: The core layer monomer is 50-70 parts of vinyl acetate, the shell layer monomer a is 30-50 parts of styrene, the shell layer monomer b is 20-32 parts of dipentene or 1-allylcyclohexene, the graft monomer is 1.5-2.5 parts of acrylonitrile, the thiol monomer is 80-280 parts of trimethylolpropane tris-3-mercaptopropionate, the active monomer is 20-420 parts, the emulsifier is 4.5-10 parts, the initiator is ammonium persulfate 0.3-0.4 parts, the pH buffer is sodium bicarbonate 0.5-1.5 parts, and the deionized water is 125-150 parts. The active monomer is hexanediol diacrylate, dipropylene glycol diacrylate, triol dimethacrylate, or trimethylolpropane trimethacrylate. The emulsifier is a mixture of equal weights of PCA507 emulsifier and PCA078 emulsifier. The preparation method of the light-curing PVAc-based water-based wood coating comprises the following steps: Step 1: Prepare the nuclear seed emulsion: Mixing deionized water, an emulsifier, and a pH buffer solution to form a pre-emulsified solution, and sequentially adding a portion of the core layer monomer and a portion of the initiator to the obtained pre-emulsified solution to obtain a core seed emulsion; Step 2: Preparation of core-shell structure emulsion: The remaining core layer monomer, the remaining initiator, the grafting monomer, the shell layer monomer a, the shell layer monomer b and the thiol monomer are sequentially added dropwise to the core seed emulsion obtained in step 1, and after the reaction, a core-shell structure emulsion containing thiolated PVAc-based core-shell latex particles is obtained; Step 3: Preparation of light-curing PVAc-based waterborne wood coating: The pre-emulsified active monomer is added dropwise to the core-shell structure emulsion system obtained in step 2 to obtain a light-cured PVAc-based water-based wood coating.

2. A light-curing PVAc-based waterborne wood coating according to claim 1, characterized in that: In step 1, the deionized water, emulsifier and pH buffer are pre-emulsified at 60° C. and a stirring rate of 250 r / min for 30 minutes; the mass fraction of the partial core layer monomer is at least 9 parts, and the partial initiator is prepared by dissolving 0.2 to 0.25 parts of initiator in 7.5 to 9.5 parts of deionized water.

3. A light-curing PVAc-based waterborne wood coating according to claim 2, characterized in that: Step 1: First, add part of the core layer monomer to the obtained pre-emulsified system and continue stirring and emulsifying for 30 minutes, then add part of the initiator and heat to 65°C. When the solution turns slightly emulsified blue and the reflux of the condenser disappears, heat to 80°C to obtain a core seed emulsion.

4. A light-curing PVAc-based waterborne wood coating according to claim 3, characterized in that: In step 2, the dropping rate of the remaining core layer monomer is 0.4-0.6 ml / min, and the remaining initiator is added 30 minutes after the start of the dropping of the remaining core layer monomer; the dropping rate of the remaining initiator is 0.1-0.2 ml / min.

5. A light-curing PVAc-based waterborne wood coating according to claim 4, characterized in that: After the remaining initiator in step 2 is added dropwise, the grafting monomer is added dropwise to the system at a rate of 1 ml / min; immediately after the grafting monomer is added dropwise, the shell monomer a is added dropwise to the system at a rate of 0.8 ml / min, and after 2 to 4 minutes of addition, the dropwise rate is adjusted to 0.3 ml / min; after the shell monomer a is added dropwise, the temperature is raised to 85°C and kept warm for 30 minutes, and then the shell monomer b is added dropwise to the system at a rate of 0.1 to 1 ml / min, and after the addition is completed, the temperature is kept warm for 30 minutes; then the system is heated to 90 to 100°C, and the thiol monomer is added dropwise to the system at a rate of 0.1 to 0.5 ml / min, and after the addition is completed, the temperature is kept warm for 30 minutes.

6. A light-curing PVAc-based waterborne wood coating according to claim 5, characterized in that: The pre-emulsified active monomer in step 3 is prepared by mixing the active monomer and water in a mass ratio of 7:3, adding 1% of the total mass of emulsifier OP-10 and performing homogeneous emulsification.

7. A light-curing PVAc-based waterborne wood coating according to claim 6, characterized in that: Step 3: When the temperature of the core-shell structure emulsion system drops to 40-70° C., the pre-emulsified active monomer is added at a dropwise acceleration rate of 0.1-0.5 ml / min.

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