A solvent type one-component polyurethane resin and a method for preparing the same

Abstract

The application belongs to the technical field of adhesives, and relates to a solvent type single-component polyurethane resin and a preparation method thereof, the solvent type single-component polyurethane resin comprising the following components in parts by weight: isocyanate 15-25 parts; macromolecular polyol 25-35 parts; addition modifier 20-30 parts; small molecule chain extender 5-10 parts; catalyst 0.05-0.3 parts; and solvent 55-65 parts. The application introduces an addition modifier, the addition modifier being formed by reacting 2,4-toluene diisocyanate and trimethylolpropane under specific conditions, and the addition modifier being helpful to improving the water resistance, alcohol resistance and easy coloring performance of the product, and interacting with other components to make the solvent type single-component polyurethane resin have excellent water resistance, alcohol resistance and coloring stability.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, and particularly relates to a solvent-based one-component polyurethane resin and its preparation method. Background Technology

[0002] Most commercially available products are two-component polyurethane resins. During production, the two components need to be processed separately, resulting in low production efficiency. In terms of application, two-component polyurethane resins require calculated mixing ratios, and the two components need to be mixed on-site. The mixing time and uniformity affect the application quality, and the resin must be used within a specified time; otherwise, it becomes unusable and wasteful, which is also not environmentally friendly. Therefore, developing a solvent-based, one-component polyurethane resin that can replace these adhesive requirements would improve production efficiency and optimize the application process.

[0003] Solvent-based one-component polyurethane resins are a class of resins composed of isocyanate-terminated high-molecular-weight polyurethane and solvents. No curing agent is required during application; the resin is directly coated onto the application point, where it reacts with trace amounts of moisture in the air to cure, thus forming a polymer with excellent properties. Furthermore, one-component polyurethane resins offer simpler and faster application processes, stable product quality, and lower requirements for the application environment, leading to their increasingly widespread use in daily life.

[0004] The water resistance, alcohol resistance, and color stability of existing solvent-based single-component polyurethane resins need to be further improved. Improved water resistance, alcohol resistance, and color stability can not only help optimize the production process and design, reduce the defect rate in the production process, but also contribute to green environmental protection. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a solvent-based single-component polyurethane resin and its preparation method.

[0006] The specific technical solution of the present invention is as follows:

[0007] The first objective of this invention is to provide a solvent-based, one-component polyurethane resin, comprising the following components in parts by weight:

[0008] Isocyanate 15-25 parts; macromolecular polyol 25-35 parts; addition modifier 20-30 parts; small molecule chain extender 5-10 parts; catalyst 0.05-0.3 parts; solvent 55-65 parts;

[0009] The addition-modified product is formed by the addition reaction of 2,4-toluene diisocyanate and trimethylolpropane.

[0010] The addition modifier helps improve the product's water resistance, alcohol resistance, and colorability.

[0011] Further, the mass ratio of the 2,4-toluene diisocyanate to the trimethylolpropane is (3.85-3.95):1.

[0012] Furthermore, the method for preparing the addition-modified body includes the following steps:

[0013] S1. Trimethylolpropane is dehydrated and then dissolved in ethyl acetate solution to obtain a trimethylolpropane solution;

[0014] S2. Add 2,4-toluene diisocyanate to the reactor, slowly add three-quarters of the trimethylolpropane solution to the reactor, and stir the reaction for 1.5-3 hours under constant temperature heating and reflux condensation to obtain the intermediate reaction solution.

[0015] S3. Heat the intermediate reaction solution to 85-90℃, continue to add the remaining trimethylolpropane solution, and stir the reaction under reflux for 1.5-3 hours to obtain an addition-modified product with an NCO mass fraction of 9.4-9.7%.

[0016] The reaction formula is as follows:

[0017]

[0018]

[0019] Further, the isocyanate is at least one selected from 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and dicyclohexylmethane diisocyanate.

[0020] Furthermore, the macromolecular polyol is at least one of poly(ethylene glycol adipate-butanediol), poly(diethylene glycol adipate-2,2-dihydroxymethylbutanol), and poly(neopentyl adipate-poly(ethylene glycol adipate)).

[0021] Furthermore, the small molecule chain extender is at least one of 1,4-butanediol and trimethylolpropane.

[0022] Furthermore, the catalyst is at least one of dibutyltin dilaurate, organobismuth, and organozinc.

[0023] Furthermore, the solvent is preferably ethyl acetate.

[0024] A second objective of this invention is to provide a method for preparing the above-mentioned solvent-based single-component polyurethane resin, comprising the following steps:

[0025] D1 isocyanate and macromolecular polyol are mixed and stirred at 75-80℃ for 1-2 hours. Then, 30-40 parts of solvent are added for dilution to obtain soft segment prepolymer A.

[0026] D2. Cool the soft segment prepolymer A obtained in step D1 to 40-50℃, add a small molecule chain extender, catalyst and 15-25 parts of solvent, heat to 75-80℃ and stir for 1.5-3 hours to prepare intermediate prepolymer B.

[0027] In step D3, the intermediate prepolymer B obtained in step D2 is cooled to 40-50℃, the addition modifier is added, and the temperature is raised to 70-75℃ and stirred for 1.5-3 hours to prepare the target product.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention introduces an addition modifier, which is formed by reacting 2,4-toluene diisocyanate and trimethylolpropane under specific conditions. The addition modifier helps to improve the water resistance, alcohol resistance and colorability of the product. Its interaction with other components enables solvent-based one-component polyurethane resin to have excellent water resistance, alcohol resistance and color stability. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0031] The raw materials used in this invention are as follows:

[0032] 2,4-Toluene diisocyanate (TDI): Industrial grade, Wanhua Chemical Group Co., Ltd.;

[0033] Poly(diethylene glycol adipate)-2,2-dimethylol butanol diol (XCP-2325): Functionality 2, molecular weight 2000 g / mol, Asahikawa Chemical Co., Ltd.

[0034] 1,4-Butanediol: Industrial grade, Sinopharm Chemical Co., Ltd.;

[0035] Trimethylolpropane (TMP): Industrial grade, Persto Chemical Company;

[0036] Organic bismuth: MB-20, BYK Chemistry.

[0037] Example 1:

[0038] A method for preparing a solvent-based one-component polyurethane resin includes the following steps:

[0039] 1. Preparation of addition-modified compounds

[0040] S1. Dehydrate 10g of trimethylolpropane and dissolve it in 65ml of ethyl acetate solution;

[0041] S2. Add 38.5g of 2,4-toluene diisocyanate to a four-necked flask, and add 49ml of trimethylolpropane solution dissolved in ethyl acetate to the four-necked flask using a constant pressure dropping funnel. Stir the reaction under constant temperature heating at 50℃ and reflux for 2h to obtain an intermediate reaction solution.

[0042] S3. The intermediate reaction solution was heated to 85°C, and the remaining trimethylolpropane solution dissolved in ethyl acetate was added dropwise. The mixture was stirred under reflux for 2 hours to obtain addition modifier 1 with an NCO mass fraction of 9.4%.

[0043] 2. Preparation of solvent-based one-component polyurethane resin

[0044] D1: 19.01g TDI and 29.57g XCP-2325 were mixed and stirred at 75℃ for 1.5h. The mixture was then diluted with 35ml of ethyl acetate to obtain soft segment prepolymer A.

[0045] D2. The soft segment prepolymer A obtained in step D1 is cooled to 40°C, and 6.72g of 1,4-butanediol, 0.12g of catalyst MB-20 and 20ml of ethyl acetate solvent are added. The mixture is heated to 75°C and stirred for 2 hours to prepare intermediate prepolymer B.

[0046] In step D3, the intermediate prepolymer B obtained in step D2 was cooled to 40°C, 25g of addition modifier 1 was added, and the mixture was heated to 70°C and stirred for 2 hours to prepare the target product 1.

[0047] Example 2:

[0048] 1. Preparation of addition-modified compounds

[0049] S1. Dehydrate 10g of trimethylolpropane and dissolve it in 65ml of ethyl acetate solution;

[0050] S2. Add 39g of 2,4-toluene diisocyanate to a four-necked flask, and add 49ml of trimethylolpropane solution dissolved in ethyl acetate to the four-necked flask using a constant pressure dropping funnel. Stir the reaction for 2h under constant temperature heating and reflux condensation to obtain an intermediate reaction solution.

[0051] S3. Heat the intermediate reaction solution to 90°C, and continue to add the remaining trimethylolpropane solution dissolved in ethyl acetate. Stir the reaction under reflux for 2.5 h to obtain addition modifier 2 with NCO mass fraction of 9.6%.

[0052] 2. Preparation of solvent-based one-component polyurethane resin

[0053] D1: 19.01g TDI and 29.57g XCP-2325 were mixed and stirred at 75℃ for 1.5h. The mixture was then diluted with 35ml of ethyl acetate to obtain soft segment prepolymer A.

[0054] D2. The soft segment prepolymer A obtained in step D1 is cooled to 40°C, and 6.72g of 1,4-butanediol, 0.12g of catalyst MB-20 and 20ml of ethyl acetate solvent are added. The mixture is heated to 75°C and stirred for 2 hours to prepare intermediate prepolymer B.

[0055] In step D3, the intermediate prepolymer B obtained in step D2 is cooled to 50°C, 25g of addition modifier 2 is added, and the mixture is heated to 70°C and stirred for 2 hours to prepare the target product 2.

[0056] Example 3:

[0057] 1. Preparation of addition-modified compounds

[0058] S1. Dehydrate 10g of trimethylolpropane and dissolve it in 65ml of ethyl acetate solution;

[0059] S2. Add 39.5g of 2,4-toluene diisocyanate to a four-necked flask, and add 49ml of trimethylolpropane solution dissolved in ethyl acetate to the four-necked flask using a constant pressure dropping funnel. Stir the reaction for 2h under constant temperature heating and reflux condensation to obtain an intermediate reaction solution.

[0060] S3. The intermediate reaction solution was heated to 90°C, and the remaining trimethylolpropane solution dissolved in ethyl acetate was added dropwise. The mixture was stirred under reflux for 2.5 h to obtain addition modifier 3 with an NCO mass fraction of 9.7%.

[0061] 2. Preparation of solvent-based one-component polyurethane resin

[0062] D1: 19.01g TDI and 29.57g XCP-2325 were mixed and stirred at 75℃ for 1.5h. The mixture was then diluted with 35ml of ethyl acetate to obtain soft segment prepolymer A.

[0063] D2. The soft segment prepolymer A obtained in step D1 is cooled to 40°C, and 6.72g of 1,4-butanediol, 0.12g of catalyst MB-20 and 20ml of ethyl acetate solvent are added. The mixture is heated to 75°C and stirred for 2 hours to prepare intermediate prepolymer B.

[0064] In step D3, the intermediate prepolymer B obtained in step D2 is cooled to 50°C, addition modifier 3 is added, and the mixture is heated to 70°C and stirred for 2 hours to prepare the target product 3.

[0065] Comparative Example 1

[0066] A method for preparing a solvent-based one-component polyurethane resin includes the following steps:

[0067] 1. Preparation of addition-modified compounds

[0068] S1. Dehydrate 10g of trimethylolpropane and dissolve it in 65ml of ethyl acetate solution;

[0069] S2. Add 38g of 2,4-toluene diisocyanate to a four-necked flask, and add 40ml of trimethylolpropane solution dissolved in ethyl acetate to the four-necked flask using a constant pressure dropping funnel. Stir the reaction for 2h under constant temperature heating and reflux condensation to obtain an intermediate reaction solution.

[0070] S3. The intermediate reaction solution was heated to 85°C, and the remaining trimethylolpropane solution dissolved in ethyl acetate was added dropwise. The mixture was stirred under reflux for 2 hours to obtain the addition modifier 4 with an NCO mass fraction of 9.35%.

[0071] 2. Preparation of solvent-based one-component polyurethane resin

[0072] D1: 19.01g TDI and 29.57g XCP-2325 were mixed and stirred at 75℃ for 1.5h. The mixture was then diluted with 35ml of ethyl acetate to obtain soft segment prepolymer A.

[0073] D2. The soft segment prepolymer A obtained in step D1 is cooled to 40°C, and 6.72g of 1,4-butanediol, 0.12g of catalyst MB-20 and 20ml of ethyl acetate solvent are added. The mixture is heated to 75°C and stirred for 2 hours to prepare intermediate prepolymer B.

[0074] In step D3, the intermediate prepolymer B obtained in step D2 is cooled to 40°C, 25g of the addition modifier 4 is added, and the mixture is heated to 70°C and stirred for 2 hours to prepare the target product 4.

[0075] Comparative Example 2

[0076] A method for preparing a solvent-based one-component polyurethane resin includes the following steps:

[0077] 1. Preparation of addition-modified compounds

[0078] S1. Dehydrate 10g of trimethylolpropane and dissolve it in 65ml of ethyl acetate solution;

[0079] S2. Add 40g of 2,4-toluene diisocyanate to a four-necked flask, and add 40ml of trimethylolpropane solution dissolved in ethyl acetate to the four-necked flask using a constant pressure dropping funnel. Stir the reaction for 2h under constant temperature heating and reflux condensation to obtain an intermediate reaction solution.

[0080] S3. Heat the intermediate reaction solution to 90°C, and continue to add the remaining trimethylolpropane solution dissolved in ethyl acetate. Stir the reaction under reflux for 2 hours to obtain addition modifier 5 with NCO mass fraction of 9.95%.

[0081] 2. Preparation of solvent-based one-component polyurethane resin

[0082] D1: 19.01g TDI and 29.57g XCP-2325 were mixed and stirred at 75℃ for 1.5h. The mixture was then diluted with 35ml of ethyl acetate to obtain soft segment prepolymer A.

[0083] D2. The soft segment prepolymer A obtained in step D1 is cooled to 40°C, and 6.72g of 1,4-butanediol, 0.12g of catalyst MB-20 and 20ml of ethyl acetate solvent are added. The mixture is heated to 75°C and stirred for 2 hours to prepare intermediate prepolymer B.

[0084] In step D3, the intermediate prepolymer B obtained in step D2 was cooled to 40°C, 25g of the addition modifier 5 was added, and the mixture was heated to 70°C and stirred for 2 hours to prepare the target product 5.

[0085] test

[0086] Water resistance test: The resins prepared in the examples and comparative examples were cast into films on a flat and clean polytetrafluoroethylene plate, dried at 20°C for 3 days, and then dried further in a vacuum drying oven at 60°C and an absolute pressure of 130 Pa for 12 hours, resulting in a film thickness of 0.8 mm. Samples of the film were cut into 30 mm × 30 mm pieces, dried in a vacuum drying oven at 50°C for 12 hours, and weighed to obtain m1. These samples were then immersed in deionized water at 20°C for 24 hours, removed, and quickly blotted dry with filter paper before weighing to obtain m2. Water absorption rate (%) = [(m2 - m1) / m1] × 100%.

[0087] Alcohol resistance test: Cut the waterborne polyurethane film into 30mm × 30mm samples, immerse them in isopropanol solvent, and place them at room temperature. If no swelling, discoloration, or bubbles appear after 72 hours, the sample is rated "5"; if the sample has slight haze around the edge area but the bulk remains clear, it is rated "3"; if swelling, discoloration, and bubbles are observed on the sample, it is rated "1".

[0088] Coloring test:

[0089] Refer to GB / T 3780.6-2007 testing standard

[0090] The test results are shown in Table 1:

[0091] Table 1 Test Data of Examples and Comparative Examples

[0092] name Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Appearance More transparent More transparent More transparent More transparent More transparent Solid content % 49.8 50.08 49.9 50.0 50.02 Viscosity (cps) 380 378 382 410 400 Water absorption rate % 1.31 1.22 1.34 4.4 3.6 Alcohol resistance grade 5 5 5 3 3 Coloring strength value % 94.2％ 92.8％ 92.7％ 78.70％ 80.52％

[0093] As can be seen from the test results in Table 1, the solvent-based single-component polyurethane resin in the embodiments of the present invention has excellent water resistance, alcohol resistance, and is easy to color and has stable coloring properties.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solvent-based one-component polyurethane resin, characterized in that, The components include the following parts by weight: Isocyanate 15-25 parts; macromolecular polyol 25-35 parts; addition modifier 20-30 parts; small molecule chain extender 5-10 parts; catalyst 0.05-0.3 parts; solvent 55-65 parts; The addition-modified product is formed by the addition reaction of 2,4-toluene diisocyanate and trimethylolpropane; The mass ratio of the 2,4-toluene diisocyanate to the trimethylolpropane is (3.85-3.95):1; The method for preparing the addition-modified body includes the following steps: S1. Trimethylolpropane is dehydrated and then dissolved in ethyl acetate solution to obtain a trimethylolpropane solution; S2. Add 2,4-toluene diisocyanate to the reactor, add three-quarters of the trimethylolpropane solution to the reactor, and stir the reaction for 1.5-3 hours under constant temperature heating and reflux condensation to obtain the intermediate reaction solution. S3. Heat the intermediate reaction solution to 85-90℃, continue to add the remaining trimethylolpropane solution, and stir the reaction under reflux for 1.5-3 hours to obtain an addition modifier with an NCO mass fraction of 9.4-9.7%. The isocyanate is at least one of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and dicyclohexylmethane diisocyanate; The macromolecular polyol is at least one of poly(ethylene glycol adipate-butanediol), poly(neopentyl adipate-poly(ethylene glycol adipate)), or poly(diethylene glycol adipate-2,2-dimethylolbutanol). The small molecule chain extender is at least one of 1,4-butanediol and trimethylolpropane; The catalyst is at least one of dibutyltin dilaurate, organobismuth, and organozinc. The solvent is ethyl acetate.

2. The method for preparing the solvent-based one-component polyurethane resin as described in claim 1, comprising the following steps: D1 involves mixing isocyanate and macromolecular polyol, stirring at 75-80℃ for 1-2 hours, and then diluting with 30-40 parts of solvent to obtain soft segment prepolymer A. D2. Cool the soft segment prepolymer A obtained in step D1 to 40-50℃, add a small molecule chain extender, catalyst and 25 parts of solvent, heat to 75-80℃ and stir for 1.5-3 hours to prepare intermediate prepolymer B. In step D3, the intermediate prepolymer B obtained in step D2 is cooled to 40-50℃, the addition modifier is added, and the temperature is raised to 70-75℃ and stirred for 1.5-3 hours to prepare the target product.

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