Low-viscosity long-pot-life impregnating resin and preparation method thereof

Abstract

The invention provides impregnating resin with low viscosity and long pot life and a preparation method thereof. Belongs to the field of impregnating resin. According to the technical key points, the adhesive comprises the following components in percentage by mass: 90-100 parts of vinyl acetate; 90 to 100 parts of a modified monomer; 1 to 1.5 parts of polyvinyl alcohol; 1.2 to 1.5 parts of dodecylphenol polyoxyethylene ether; 1.5 to 1.8 parts of sodium chloride; 0.3 to 0.4 part of ammonium persulfate; 1.3 to 1.4 parts of sodium bicarbonate; 90 to 100 parts of distilled water; 3 to 4.3 parts of styrene; silicone oil; 2 to 6 parts; and 1.1 to 1.3 parts of sodium hydroxide. The method comprises the following steps: S1, adding a mixed solution of a sodium hydroxide solution and a sodium chloride solution into a modified monomer, washing for 3-5 times, filtering and separating the monomer, and washing for 3-5 times by using distilled water; the invention aims to provide impregnating resin with low viscosity and long pot life and a preparation method thereof. The impregnating resin is used for enabling the impregnating efficiency to be higher when the whole impregnating resin is used, and meanwhile, the impregnating requirement of a high-density base material can be met.

Description

Technical Field

[0001] This invention relates to the field of impregnation resins, specifically a low-viscosity, long-life impregnation resin and its preparation method. Background Technology

[0002] Impregnating resins are a type of resin that uses cross-linked copolymers as a carrier for adsorption, impregnating the resin in a liquid extractant to absorb various liquid ion exchangers. They are used in the production of reinforced composite materials to impregnate various skeleton materials such as wood, fabrics, carbon fibers, or glass fibers. Commonly used resins include epoxy and phenolic resins. With increasing environmental protection requirements, solvent-free impregnating varnishes have become an important application area for epoxy resins. By heating epoxy resin and adding various components for mixing, one-component solvent-free impregnating varnishes can be prepared for various applications requiring high-performance coatings.

[0003] Currently, the most widely used impregnating resins in impregnated paper-faced panels are urea-formaldehyde resin, melamine resin, and thermosetting phenolic resin. However, due to the small amount of free phenol in phenolic resin, its high curing temperature, and dark color of the adhesive layer, the market acceptance of veneered engineered wood panels is low, and the decorative properties of the products are poor, thus limiting their application. Urea-formaldehyde resin is widely used in wood bonding and other fields due to its excellent bonding performance and good aging resistance. However, urea-formaldehyde resin also has problems such as poor water resistance and weather resistance, and it is easy to release formaldehyde during use. Moreover, urea-formaldehyde resin, melamine resin, and thermosetting phenolic resin have high viscosity, resulting in low impregnation efficiency during impregnation processing, and it is difficult to meet the impregnation requirements of high-density substrates. Summary of the Invention

[0004] The purpose of this invention is to provide a low-viscosity, long-life impregnation resin and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A low-viscosity, long-life impregnation resin, comprising the following components by weight percentage:

[0007] Vinyl acetate: 90-100 parts;

[0008] Modified monomer: 90-100 parts;

[0009] Polyvinyl alcohol: 1-1.5 parts;

[0010] Dodecylphenol polyoxyethylene ether: 1.2-1.5 parts;

[0011] Sodium chloride: 1.5-1.8 parts;

[0012] Ammonium persulfate: 0.3-0.4 parts;

[0013] Sodium bicarbonate: 1.3-1.4 parts;

[0014] Distilled water: 90-100 parts;

[0015] Styrene: 3-4.3 parts;

[0016] Silicone oil; 2-6 parts;

[0017] Sodium hydroxide: 1.1-1.3 parts.

[0018] As a further aspect of the present invention: the sodium bicarbonate is a 5% sodium bicarbonate solution, and the sodium chloride is a 20% sodium chloride solution.

[0019] As a further aspect of the present invention: the modified monomer is one or a mixture of two of methyl acrylate and methyl methacrylate.

[0020] A method for preparing a low-viscosity, long-pot-life impregnation resin includes the following steps;

[0021] S1: Wash the modified monomer 3-5 times with a mixture of sodium hydroxide solution and sodium chloride solution, then filter and separate the monomer, and then wash it 3-5 times with distilled water to obtain the mixed monomer for later use.

[0022] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir, while raising the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol.

[0023] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0024] S4: Heat to 72-75℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0025] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials, and three drops of initiator solution are added every 15 minutes.

[0026] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0027] S7: After the temperature rises to 90-95℃, maintain the temperature for 30 minutes, then add styrene and stir. Then lower the temperature to 70℃, add the neutralizing agent sodium bicarbonate solution, adjust the pH to near neutral, and then discharge the material after cooling to room temperature.

[0028] As a further aspect of the present invention: the addition ratio of the modified monomer, sodium hydroxide solution and sodium chloride solution in S1 is 5:1:1.

[0029] As a further aspect of the present invention: the remaining mixed monomers in step S5 need to be added dropwise over 3-5 hours.

[0030] As a further aspect of the present invention: the number of times distilled water is used to wash in S1 is specifically until the modified monomer is clarified and becomes neutral.

[0031] As a further aspect of the present invention: in step S7, after adding a neutralizing agent sodium bicarbonate solution to adjust the pH to near neutral, silicone oil is added and stirred evenly.

[0032] As a further aspect of the present invention: in step S2, distilled water and polyvinyl alcohol are added to the reaction vessel and stirred at a speed of 150-300 r / min.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] In this invention, the above-mentioned structure is adopted, and a copolymerization reaction is carried out using methyl acrylate and methyl methacrylate as modified monomers of vinyl acetate, with the addition of styrene as an auxiliary agent. Since methyl groups have no adhesive force, the steric hindrance of the polymer monomer chain is increased by utilizing the effect of methyl methacrylate, thereby reducing the polymer adhesive strength. At the same time, under the action of an initiator, styrene undergoes a crosslinking reaction with -CH=CH- (vinylene groups) in the unsaturated polyester to form a thermosetting unsaturated polyester resin with a three-dimensional structure. This crosslinking reaction not only enhances the mechanical properties of the resin, but also further reduces the viscosity of the resin, making it exhibit better flowability and filling properties during the curing process. This results in higher impregnation efficiency of the entire impregnation resin during use, and can meet the impregnation requirements of high-density substrates. Detailed Implementation

[0035] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0036] A low-viscosity, long-life impregnation resin, comprising the following components by weight percentage:

[0037] Vinyl acetate: 90-100 parts; modified monomer: 90-100 parts; polyvinyl alcohol: 1-1.5 parts; wherein polyvinyl alcohol serves as a protective colloid and emulsifier; dodecylphenol polyoxyethylene ether: 1.2-1.5 parts; sodium chloride: 1.5-1.8 parts; sodium hydroxide: 1.1-1.3 parts; wherein the sodium bicarbonate is a 5% sodium bicarbonate solution and the sodium chloride is a 20% sodium chloride solution; specifically, the water used to prepare the 5% sodium bicarbonate solution and the 20% sodium chloride solution is deionized distilled water.

[0038] Ammonium persulfate: 0.3-0.4 parts; used as an initiator for the entire copolymerization reaction; Sodium bicarbonate: 1.3-1.4 parts; used to adjust the pH value during the reaction process; Distilled water: 90-100 parts; Styrene: 3-4.3 parts; Styrene can undergo a cross-linking reaction with the -CH=CH- (vinylene group) in the unsaturated polyester under the action of the initiator to form a thermosetting unsaturated polyester resin with a three-dimensional structure. This cross-linking reaction not only enhances the mechanical properties of the resin but also further reduces the viscosity of the resin, making it exhibit better flowability and filling properties during the curing process, improving the wettability of the resin to reinforcing materials and fillers, and extending the pot life of the cured system. Silicone oil: 2-6 parts are set as a leveling agent and dispersant to improve the overall flowability of the resin. The modified monomer is one or a mixture of methyl acrylate and methyl methacrylate.

[0039] A method for preparing a low-viscosity, long-life impregnation resin includes the following steps: S1: Washing the modified monomer 3-5 times with a mixed solution of sodium hydroxide and sodium chloride, wherein the ratio of modified monomer, sodium hydroxide solution, and sodium chloride solution is 5:1:1. After that, the monomer is filtered and separated, and then washed 3-5 times with distilled water. The specific number of times of washing with distilled water is until the modified monomer is clear and neutral, to obtain a mixed monomer for later use. Since monomer manufacturers add a certain amount of polymerization inhibitor after the monomer is produced to prevent self-polymerization during transportation and storage, in order to ensure the efficiency of the emulsion polymerization reaction, methyl acrylate and methyl methacrylate need to be pretreated before emulsion polymerization. Washing with a mixed solution of sodium hydroxide and sodium chloride followed by washing with distilled water can effectively remove the polymerization inhibitor from the monomer.

[0040] S2: Add distilled water and polyvinyl alcohol to the reactor and stir at a speed of 150-300 r / min. In the initial stage of the reaction, too fast a stirring speed will prolong the polymer induction period. In the middle stage of the reaction, the polymer has basically formed, and the swollen polymer particles gradually remove emulsifier molecules from the monomer droplets, making the latter unstable and thus reducing the surface area. The reaction is then controlled by the diffusion of monomers through the aqueous phase to the polymer particles. Appropriately increasing the stirring speed will increase the reaction rate. The later stage of the reaction is basically the same as the middle stage. Simultaneously, raise the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol.

[0041] S3: Then cool to 60℃ and add all the emulsifier and 1 / 3 of the total amount of ammonium persulfate; the polymerization conversion rate gradually increases with the increase of ammonium persulfate (initiator): when the initiator dosage is 4%, the change in conversion rate tends to level off. To improve the conversion rate of the polymerization reaction, the concentration of initiator can be appropriately increased, but if the initiator concentration is too high, the polymerization rate will be too fast, the molecular weight will be smaller, and the stability will be worse. Therefore, a 4% initiator dosage is more appropriate. By increasing the holding time, the conversion rate can be further improved. Specifically, a certain amount of initiator is added first, and after the reaction starts, the initiator is added dropwise to maintain an appropriate initiator concentration.

[0042] S4: Heat to 72-75℃ and add 1 / 4 of the total mixed monomers dropwise over 30 minutes. S5: When the reactants exhibit blue fluorescence and the system temperature rises automatically, polymerization has begun. Then, when the temperature reaches 80℃, begin adding the remaining mixed monomers dropwise. The dropping rate depends on the reflux state of the material. The remaining mixed monomers should be added over 3-5 hours, with three drops of initiator solution added every 15 minutes. S6: After adding the mixed monomers, maintain stirring for 10 minutes, then begin heating while simultaneously adding the remaining initiator solution. This maintains the main reaction and reduces the content of free monomers. S7: After the temperature reaches 90-95℃, maintain the temperature for 30 minutes. Then add styrene and stir. Reduce the temperature to 70℃, add a neutralizing agent (sodium bicarbonate solution) to adjust the pH to near neutral, add silicone oil, and stir thoroughly to improve the fluidity of the resulting resin. After cooling to room temperature, discharge the material.

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0044] Example 1, S1: The modified monomer was washed 5 times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution was 5:1:1. The monomer was then filtered and separated, and then washed 5 times with distilled water. The specific number of times of washing with distilled water was until the modified monomer was clear and neutral, and a mixed monomer was obtained for later use.

[0045] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 150 r / min. At the same time, raise the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol.

[0046] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0047] S4: Heat to 72℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0048] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials. The remaining mixed monomers must be added in 5 hours, and three drops of initiator solution are added every 15 minutes.

[0049] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0050] S7: After the temperature rises to 95℃, maintain the temperature for 30 minutes. Then add styrene and stir. Then lower the temperature to 70℃, add sodium bicarbonate solution as a neutralizing agent to adjust the pH to near neutral, add silicone oil and stir evenly to improve the fluidity of the resulting resin. After cooling to room temperature, discharge the material.

[0051] The composition includes: vinyl acetate (90 parts); modified monomer (100 parts); polyvinyl alcohol (1.2 parts); dodecylphenol polyoxyethylene ether (1.25 parts); sodium chloride (1.58 parts); ammonium persulfate (0.34 parts); sodium bicarbonate (1.34 parts); distilled water (91 parts); styrene (33 parts); silicone oil (2.6 parts); and sodium hydroxide (1.3 parts). The modified monomer is methyl acrylate. The viscosity of the resulting impregnating resin is 0.24 Pa·s.

[0052] Example 2, S1: Wash the modified monomer 5 times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution is 5:1:1. Then filter and separate the monomer, and then wash it 5 times with distilled water. The specific number of times to wash with distilled water is until the modified monomer is clear and neutral, to obtain a mixed monomer for later use.

[0053] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 300 r / min. At the same time, raise the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol.

[0054] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0055] S4: Heat to 75℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0056] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials. The remaining mixed monomers must be added in 5 hours, and three drops of initiator solution are added every 15 minutes.

[0057] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0058] S7: After the temperature rises to 95℃, maintain the temperature for 30 minutes. Then add styrene and stir. Then lower the temperature to 70℃, add sodium bicarbonate solution as a neutralizing agent to adjust the pH to near neutral, add silicone oil and stir evenly to improve the fluidity of the resulting resin. After cooling to room temperature, discharge the material.

[0059] The composition of the impregnating resin is as follows: vinyl acetate: 100 parts; modified monomer: 90 parts; polyvinyl alcohol: 1.22 parts; dodecylphenol polyoxyethylene ether: 1.25 parts; sodium chloride: 1.58 parts; ammonium persulfate: 0.34 parts; sodium bicarbonate: 1.34 parts; distilled water: 91 parts; styrene: 33 parts; silicone oil: 2.62 parts; sodium hydroxide: 1.35 parts. The modified monomer is methyl methacrylate. The viscosity of the resulting impregnating resin is 0.01 Pa·s after measurement.

[0060] Example 3, S1: Wash the modified monomer 3-5 times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution is 5:1:1. Then filter and separate the monomer, and then wash it 3-5 times with distilled water. The specific number of times to wash with distilled water is until the modified monomer is clear and neutral to obtain a mixed monomer for later use.

[0061] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 150-300 r / min. At the same time, raise the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol.

[0062] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0063] S4: Heat to 72-75℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0064] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, start adding the remaining mixed monomers. The adding rate depends on the reflux state of the materials. The addition of the remaining mixed monomers should be completed in 3-5 hours, and three drops of initiator solution should be added every 15 minutes.

[0065] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0066] S7: After the temperature rises to 90-95℃, maintain the temperature for 30 minutes. Then add styrene and stir. Then lower the temperature to 70℃, add sodium bicarbonate solution as a neutralizing agent to adjust the pH to near neutral, add silicone oil and stir evenly to improve the fluidity of the resulting resin. After cooling to room temperature, discharge the material.

[0067] The composition of the impregnating resin is as follows: vinyl acetate: 95 parts; modified monomer: 100 parts; polyvinyl alcohol: 1.35 parts; dodecylphenol polyoxyethylene ether: 1.25 parts; sodium chloride: 1.6 parts; ammonium persulfate: 0.314 parts; sodium bicarbonate: 1.34 parts; distilled water: 100 parts; styrene: 3.43 parts; silicone oil: 3 parts; sodium hydroxide: 1.13 parts. The modified monomer is methyl methacrylate. The viscosity of the resulting impregnating resin is 0.013 Pa·s after measurement.

[0068] Example 4, S1: Wash the modified monomer four times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution is 5:1:1. Then filter and separate the monomer, and then wash it four times with distilled water. The specific number of times to wash with distilled water is until the modified monomer is clear and neutral, to obtain a mixed monomer for later use.

[0069] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 200 r / min. At the same time, raise the temperature to 92℃ to completely dissolve the polyvinyl alcohol.

[0070] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0071] S4: Heat to 74℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0072] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials. The remaining mixed monomers should be added in 3.6 hours, and three drops of initiator solution should be added every 15 minutes.

[0073] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0074] S7: After the temperature rises to 94℃, the reaction is kept at a constant temperature for 30 minutes. Then, styrene is added and stirred. The temperature is then lowered to 70℃, and a neutralizing agent, sodium bicarbonate solution, is added to adjust the pH to near neutral. Silicone oil is added and stirred evenly to improve the fluidity of the resulting resin. After cooling to room temperature, the material is discharged.

[0075] The composition of the impregnating resin is as follows: vinyl acetate: 100 parts; modified monomer: 100 parts; polyvinyl alcohol: 1.5 parts; dodecylphenol polyoxyethylene ether: 1.5 parts; sodium chloride: 1.8 parts; ammonium persulfate: 0.4 parts; sodium bicarbonate: 1.4 parts; distilled water: 100 parts; styrene: 4.3 parts; silicone oil: 6 parts; sodium hydroxide: 1.3 parts. The modified monomer is a mixture of methyl methacrylate and methyl acrylate in a 1:1 ratio. The viscosity of the resulting impregnating resin is measured to be 0.027 Pa·s.

[0076] Example 5, S1: Wash the modified monomer 4 times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution is 5:1:1. Then filter and separate the monomer, and then wash it 3-5 times with distilled water. The specific number of times to wash with distilled water is until the modified monomer is clear and neutral to obtain a mixed monomer for later use.

[0077] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 200 r / min. At the same time, raise the temperature to 92℃ to completely dissolve the polyvinyl alcohol.

[0078] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0079] S4: Heat to 75℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0080] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials. The remaining mixed monomers must be added in 5 hours, and three drops of initiator solution are added every 15 minutes.

[0081] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0082] S7: After the temperature rises to 90-95℃, maintain the temperature for 30 minutes. Then add styrene and stir. Then lower the temperature to 70℃, add sodium bicarbonate solution as a neutralizing agent to adjust the pH to near neutral, add silicone oil and stir evenly to improve the fluidity of the resulting resin. After cooling to room temperature, discharge the material.

[0083] The composition of the impregnating resin is as follows: vinyl acetate: 90 parts; modified monomer: 90 parts; polyvinyl alcohol: 1 part; dodecylphenol polyoxyethylene ether: 1.25 parts; sodium chloride: 1.58 parts; ammonium persulfate: 0.34 parts; sodium bicarbonate: 1.34 parts; distilled water: 90 parts; styrene: 4.1 parts; silicone oil: 2.6 parts; sodium hydroxide: 1.3 parts. The modified monomer is a mixture of methyl methacrylate and methyl acrylate in a ratio of 4:1. The viscosity of the resulting impregnating resin is 0.0231 Pa·s.

[0084] Example 6, S1: Wash the modified monomer four times with a mixed solution of sodium hydroxide solution and sodium chloride solution. The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution is 5:1:1. Then filter and separate the monomer, and then wash it four times with distilled water. The specific number of times to wash with distilled water is until the modified monomer is clear and neutral, to obtain a mixed monomer for later use.

[0085] S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir at a speed of 250 r / min. At the same time, raise the temperature to 91℃ to completely dissolve the polyvinyl alcohol.

[0086] S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount;

[0087] S4: Heat to 74℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes;

[0088] S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials. The remaining mixed monomers must be added in 4 hours, and three drops of initiator solution are added every 15 minutes.

[0089] S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution.

[0090] S7: After the temperature rises to 93℃, the reaction is kept at a constant temperature for 30 minutes. Then, styrene is added and stirred. The temperature is then lowered to 70℃, and a neutralizing agent, sodium bicarbonate solution, is added to adjust the pH to near neutral. Silicone oil is added and stirred evenly to improve the fluidity of the resulting resin. After cooling to room temperature, the material is discharged.

[0091] The composition of the impregnating resin is as follows: vinyl acetate: 95 parts; modified monomer: 95 parts; polyvinyl alcohol: 1.5 parts; dodecylphenol polyoxyethylene ether: 1.35 parts; sodium chloride: 1.7 parts; ammonium persulfate: 0.36 parts; sodium bicarbonate: 1.38 parts; distilled water: 100 parts; styrene: 4.1 parts; silicone oil: 4 parts; sodium hydroxide: 1.2 parts. The modified monomer is a mixture of methyl methacrylate and methyl acrylate in a ratio of 1:4. The viscosity of the resulting impregnating resin is measured to be 0.067 Pa·s.

[0092] Based on the measurement results of the resin viscosity prepared in each embodiment, it can be seen that the higher the proportion of methyl methacrylate in the modified monomer, the lower the viscosity of the prepared resin. The main reason is that methyl groups have no binding force. When the proportion of methyl methacrylate increases, the steric hindrance of the polymer monomer chain increases due to the action of methyl groups, thereby reducing the bonding strength of the obtained resin.

[0093] The above-described embodiments are preferred embodiments of the present invention and are only used to facilitate the illustration of the present invention. They are not intended to limit the present invention in any way. Any person skilled in the art who makes local modifications or alterations to the technical content disclosed in the present invention without departing from the scope of the technical features of the present invention shall still fall within the scope of the technical features of the present invention.

Claims

1. A low-viscosity, long-lasting impregnation resin, characterized in that, It includes the following components by mass percentage: Vinyl acetate: 90-100 parts; Modified monomer: 90-100 parts; Polyvinyl alcohol: 1-1.5 parts; Dodecylphenol polyoxyethylene ether: 1.2-1.5 parts; Sodium chloride: 1.5-1.8 parts; Ammonium persulfate: 0.3-0.4 parts; Sodium bicarbonate: 1.3-1.4 parts; Distilled water: 90-100 parts; Styrene: 3-4.3 parts; Silicone oil; 2-6 parts; Sodium hydroxide: 1.1-1.3 parts.

2. The low-viscosity, long-life impregnation resin according to claim 1, characterized in that, The sodium bicarbonate is a 5% sodium bicarbonate solution, and the sodium chloride is a 20% sodium chloride solution.

3. The low-viscosity, long-life impregnation resin according to claim 1, characterized in that, The modified monomer is one or a mixture of two of methyl acrylate and methyl methacrylate.

4. A method for preparing a low-viscosity, long-lasting impregnation resin, characterized in that, Includes the following steps; S1: Wash the modified monomer 3-5 times with a mixture of sodium hydroxide solution and sodium chloride solution, then filter and separate the monomer, and then wash it 3-5 times with distilled water to obtain the mixed monomer for later use. S2: Add distilled water and polyvinyl alcohol to the reaction vessel and stir, while raising the temperature to 90±2℃ to completely dissolve the polyvinyl alcohol. S3: Then cool to 60°C and add all the emulsifier and ammonium persulfate equivalent to 1 / 3 of the total amount; S4: Heat to 72-75℃ and add 1 / 4 of the total amount of mixed monomers dropwise over 30 minutes; S5: When the reactants show blue fluorescence and the system temperature rises automatically, it indicates that polymerization has started. Then, when the temperature rises to 80°C, the remaining mixed monomers are added dropwise. The dropping rate depends on the reflux state of the materials, and three drops of initiator solution are added every 15 minutes. S6: After adding the mixed monomers, keep stirring for 10 minutes, then start heating while adding the remaining initiator solution. S7: After the temperature rises to 90-95℃, maintain the temperature for 30 minutes, then add styrene and stir. Then lower the temperature to 70℃, add the neutralizing agent sodium bicarbonate solution, adjust the pH to near neutral, and then discharge the material after cooling to room temperature.

5. The method for preparing a low-viscosity, long-life impregnation resin according to claim 4, characterized in that, The ratio of modified monomer, sodium hydroxide solution and sodium chloride solution added in S1 is 5:1:

1.

6. The method for preparing a low-viscosity, long-life impregnation resin according to claim 4, characterized in that, The remaining mixed monomers in S5 need to be added dropwise over 3-5 hours.

7. The method for preparing a low-viscosity, long-life impregnation resin according to claim 4, characterized in that, The number of times distilled water is used in S1 is specifically determined until the modified monomer is clarified and becomes neutral.

8. The method for preparing a low-viscosity, long-life impregnation resin according to claim 4, characterized in that, In step S7, after adding a neutralizing agent, sodium bicarbonate solution, to adjust the pH to near neutral, silicone oil is added and stirred until homogeneous.

9. The method for preparing a low-viscosity, long-life impregnation resin according to claim 4, characterized in that, In step S2, distilled water and polyvinyl alcohol are added to the reactor and stirred at a speed of 150-300 r / min.