Production process of solvent-free PU resin

Abstract

The invention relates to the technical field of polyurethane, in particular to a solvent-free PU resin production process which comprises the following steps: S1, introducing a PSSA homopolymer, polyester polyol, polyether polyol, diphenylmethane, castor oil, organic bismuth, an antioxidant 1010, glycerol and gamma-aminopropyltriethoxysilane into a mixing kettle, and uniformly stirring to obtain a component A; s2, a PAI precursor, dicyclohexylcarbodiimide, toluene diisocynate and diisocyanate are introduced into the mixing kettle and stirred to be uniform, and a component B is obtained; and S3, introducing the component A and the component B into a reaction kettle, heating the reaction system, and stirring to obtain the paint. The solvent-free PU resin prepared by the invention has good mechanical strength and thermal stability, and also has certain fluidity.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane, and in particular to a production process of solvent-free PU resin. Background Art

[0002] Polyurethane (PU) is a high-performance polymer material. Due to its unique physical and chemical properties and wide application fields, it occupies an important position in modern industry. Polyurethane resins are mainly divided into two categories: single-component and two-component. Two-component polyurethane resins can be further divided into solvent-based and solvent-free types according to whether they contain solvents. Solvent-based polyurethane resins have the advantages of high cost-effectiveness and convenient construction. However, the solvent will evaporate into the air during use, causing environmental pollution. Solvent-free polyurethane resins are usually composed of two components, A and B, of which component A mainly contains terminal hydroxyl polyols, and component B is a polyurethane prepolymer terminated with isocyanate groups (-NCO). Solvent-free polyurethane resins do not contain solvents, which can reduce the volatilization of harmful substances, thereby improving the safety of the operating environment. Secondly, after the two components are mixed, they can quickly show good initial adhesion and have a certain bonding strength without the need for additional drying or heating systems. In addition, solvent-free polyurethane resins also have excellent low temperature resistance and flexibility.

[0003] In the prior art, compared with solvent-based polyurethane resins, the initial adhesion of solvent-free adhesives is poor. In order to achieve a comparable initial adhesion, the amount of adhesive applied often needs to be increased, which increases the cost of use to a certain extent. Secondly, due to the large molecular weight of solvent-free adhesives, their fluidity and wettability will be affected. In the absence of solvent for dilution, it is often necessary to reduce the molecular weight to achieve this, thus affecting other properties of the resin. In addition, solvent-free adhesives are deficient in hydrolysis resistance and corrosion resistance. When immersed in water for a long time or in a high temperature environment, their bonding strength will decrease significantly. Summary of the invention

[0004] In order to solve the problems mentioned in the above background technology, the present invention provides a production process of solvent-free PU resin.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A production process of solvent-free PU resin comprises the following steps:

[0007] S1. Pump ethyl 2-bromoisobutyrate and N,N-dimethylformamide into a reaction kettle, stir to dissolve and degas, then introduce nitrogen protection, add copper bromide and pentamethyldiethylenetriamine under nitrogen atmosphere, prepare 20-30wt% styrene sulfonic acid monomer solution with N,N-dimethylformamide, heat the reaction system, slowly drop styrene sulfonic acid (SSA) monomer solution, keep warm after the dropwise addition, and after the reaction is completed, perform vacuum distillation to obtain PSSA homopolymer, introduce PSSA homopolymer, polyester polyol, polyether polyol, diphenylmethane, castor oil, organic bismuth (DY-20), antioxidant 1010, glycerol and γ-aminopropyltriethoxysilane into a mixing kettle, stir evenly at a speed of 50-100rpm to obtain component A;

[0008] S2, pumping N-methylacrylimide (N-MAI) and N,N-dimethylformamide into a reactor, stirring to completely dissolve N-MAI, using a degasser to degas, remove oxygen and other impurities, introducing nitrogen, adding azobisisobutyronitrile (AIBN) under nitrogen protection, heating to initiate polymerization of N-MAI, stirring the reaction at a speed of 50-100 rpm, cooling to room temperature, adding ethanolamine under nitrogen protection, performing a ring-opening reaction, introducing a hydroxyl functional group, stirring the reaction at room temperature or 30-50° C. for 2-4 hours, cooling to room temperature after the reaction, performing reduced pressure distillation with a vacuum pump to remove unreacted N-MAI, ethanolamine, solvent and other impurities, and obtaining a PAI precursor, introducing a PAI precursor, dicyclohexylcarbodiimide, toluene diisocyanate and diisocyanate into a mixing kettle, stirring evenly at a speed of 50-100 rpm, and obtaining a B component;

[0009] S3. Add component A and component B in a mass ratio of 1:1 into a reaction kettle, heat the reaction system, and stir at a speed of 100-200 rpm for 1-5 hours to obtain a solvent-free PU resin.

[0010] Furthermore, in step S1, the feed mass ratio of ethyl 2-bromoisobutyrate, N,N-dimethylformamide, copper bromide, pentamethyldiethylenetriamine and styrene sulfonic acid monomer solution is (4-6):10:(0.1-0.5):(0.3-0.4):(20-30).

[0011] Furthermore, in step S1, the temperature of the reaction system is raised to 80-90° C., and the insulation reaction time is 4-6 hours.

[0012] Furthermore, in step S1, the mass ratio of PSSA homopolymer, polyester polyol, polyether polyol, diphenylmethane, castor oil, organic bismuth, antioxidant 1010, glycerol and γ-aminopropyltriethoxysilane is (8-10): (44-46): (10-13): (1-3): (4-5): (0.06-0.08): (0.06-0.08): (8-10): (0.6-0.7).

[0013] Furthermore, in step S1, the polyester polyol includes one or more of polyethylene terephthalate diol, polypropylene terephthalate diol, polybutylene terephthalate diol and polyethylene adipate diol, and the polyether polyol includes one or more of polypropylene glycol, polybutylene glycol and polytetramethylene glycol.

[0014] Furthermore, in step S2, the feed mass ratio of N-methylacrylimide, N,N-dimethylformamide, azobisisobutyronitrile and ethanolamine is (3-6):10:(0.5-0.9):(0.03-0.1).

[0015] Furthermore, in step S2, the feed mass ratio of PAI precursor, dicyclohexylcarbodiimide, toluene diisocyanate and diisocyanate is (5-7): (0.2-0.6): (4-6): (18-22).

[0016] Furthermore, in step S2, the temperature of the reaction system is raised to 60-80° C., and the stirring reaction time is 4-8 hours.

[0017] Furthermore, in step S3, the temperature of the reaction system is raised to 60-70°C.

[0018] Beneficial effects of the present invention:

[0019] 1. The solvent-free PU resin prepared by the present invention is composed of a plurality of polymer chains connected by polymerization reaction, wherein the mixing of PSSA homopolymer and polyol and the reaction of PAI precursor and isocyanate not only extend the length of the polymer chain but also increase its complexity, so that the resin has higher tensile strength, elongation at break and impact toughness, thereby improving its mechanical properties.

[0020] 2. There are a large number of crosslinking points in the solvent-free PU resin prepared by the present invention, which are formed by the addition polymerization reaction of the crosslinking agent or chain extender and the isocyanate group with the functional groups such as hydroxyl and amino groups, so that the resin has a higher molecular weight and stronger cohesion. The presence of the crosslinking structure limits the movement of the molecular chain, improves the thermal stability of the resin, enables it to maintain stable performance at high temperatures, and also gives it good fluidity and processability. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0023] Example 1

[0024] A production process of solvent-free PU resin comprises the following steps:

[0025] S1. Pump 4kg of ethyl 2-bromoisobutyrate and 10kg of N,N-dimethylformamide into a reactor, stir to dissolve and degas, then introduce nitrogen protection, add 0.1kg of copper bromide and 0.3kg of pentamethyldiethylenetriamine under a nitrogen atmosphere, prepare a 20wt% styrene sulfonic acid monomer solution with N,N-dimethylformamide, heat the reaction system to 80°C, slowly drop 20kg of styrene sulfonic acid monomer solution, and after the dropwise addition is completed, keep the reaction warm for 4h. After the reaction is completed, distill under reduced pressure to obtain a PSSA homopolymer, and introduce 8kg of PSSA homopolymer, 44kg of polyethylene terephthalate glycol, 10kg of polypropylene glycol, 1kg of diphenylmethane, 4kg of castor oil, 0.06kg of organic bismuth, 0.06kg of antioxidant 1010, 8kg of glycerol and 0.6kg of γ-aminopropyltriethoxysilane into a mixing kettle, and stir evenly at a speed of 50rpm to obtain component A;

[0026] S2, 3kgN-methacrylimide and 10kgN,N-dimethylformamide were pumped into the reactor, degassed using a degasser, nitrogen was introduced, 0.5kg of azobisisobutyronitrile was added under nitrogen protection, the temperature was raised to 60°C, the reaction was stirred at 50rpm for 4h, the temperature was lowered to room temperature, 0.03kg of ethanolamine was added under nitrogen protection, the reaction was stirred at room temperature for 2h, after the reaction was completed, the reaction was cooled to room temperature, and a vacuum pump was used for reduced pressure distillation to obtain a PAI precursor, 5kgPAI precursor, 0.2kg dicyclohexylcarbodiimide, 4kg toluene diisocyanate and 18kg diisocyanate were introduced into a mixing kettle, and stirred at 50rpm to obtain component B;

[0027] S3. 10 kg of component A and 10 kg of component B were introduced into a reaction kettle, the reaction system was heated to 60° C., and stirred at a speed of 100 rpm for 1 hour to obtain a solvent-free PU resin.

[0028] Example 2

[0029] A production process of solvent-free PU resin comprises the following steps:

[0030] S1. Pump 4.5 kg of ethyl 2-bromoisobutyrate and 10 kg of N, N-dimethylformamide into a reactor, stir to dissolve and degas, then introduce nitrogen protection, add 0.2 kg of copper bromide and 0.33 kg of pentamethyldiethylenetriamine under nitrogen atmosphere, prepare 22 wt% styrene sulfonic acid monomer solution with N, N-dimethylformamide, heat the reaction system to 85 ° C, slowly add 23 kg of styrene sulfonic acid monomer solution, and after the addition is complete, keep the reaction warm for 5 minutes. h, after the reaction was completed, the mixture was distilled under reduced pressure to obtain a PSSA homopolymer, and 8.6 kg of PSSA homopolymer, 44.4 kg of polytrimethylene terephthalate glycol, 11 kg of polybutylene glycol, 1.5 kg of diphenylmethane, 4.3 kg of castor oil, 0.062 kg of organic bismuth, 0.061 kg of antioxidant 1010, 8.8 kg of glycerol and 0.61 kg of γ-aminopropyltriethoxysilane were introduced into a mixing kettle and stirred evenly at a speed of 60 rpm to obtain component A;

[0031] S2, 4kgN-methacrylimide and 10kgN,N-dimethylformamide were pumped into the reactor, degassed using a degasser, nitrogen was introduced, 0.6kg of azobisisobutyronitrile was added under nitrogen protection, the temperature was raised to 65°C, the reaction was stirred at 60rpm for 5h, the temperature was lowered to room temperature, 0.04kg of ethanolamine was added under nitrogen protection, the reaction was stirred at 35°C for 3h, after the reaction was completed, the reaction was cooled to room temperature, and a vacuum pump was used for reduced pressure distillation to obtain a PAI precursor, 5.5kgPAI precursor, 0.3kg dicyclohexylcarbodiimide, 4.5kg toluene diisocyanate and 19kg diisocyanate were introduced into a mixing kettle, and stirred at 60rpm to obtain component B;

[0032] S3. 10 kg of component A and 10 kg of component B were introduced into a reaction kettle, the reaction system was heated to 62° C., and stirred at a speed of 150 rpm for 2 h to obtain a solvent-free PU resin.

[0033] Example 3

[0034] A production process of solvent-free PU resin comprises the following steps:

[0035] S1. Pump 5kg of ethyl 2-bromoisobutyrate and 10kg of N,N-dimethylformamide into a reactor, stir to dissolve and degas, then introduce nitrogen protection, add 0.4kg of copper bromide and 0.35kg of pentamethyldiethylenetriamine under nitrogen atmosphere, prepare 25wt% styrene sulfonic acid monomer solution with N,N-dimethylformamide, heat the reaction system to 85°C, slowly drop 25kg of styrene sulfonic acid monomer solution, and after the dropwise addition is completed, keep The mixture was reacted at room temperature for 5 hours. After the reaction was completed, the mixture was distilled under reduced pressure to obtain a PSSA homopolymer. 9 kg of PSSA homopolymer, 45 kg of polybutylene terephthalate glycol, 12 kg of polypropylene glycol, 2 kg of diphenylmethane, 4.5 kg of castor oil, 0.07 kg of organic bismuth, 0.07 kg of antioxidant 1010, 9 kg of glycerol and 0.65 kg of γ-aminopropyltriethoxysilane were introduced into a mixing kettle and stirred at a speed of 60 rpm to obtain component A.

[0036] S2, 5kgN-methacrylimide and 10kgN,N-dimethylformamide were pumped into the reactor, degassed using a degasser, nitrogen was introduced, 0.8kg of azobisisobutyronitrile was added under nitrogen protection, the temperature was raised to 75°C, the reaction was stirred at 60rpm for 6h, the temperature was lowered to room temperature, 0.08kg of ethanolamine was added under nitrogen protection, the reaction was stirred at 40°C for 3h, after the reaction was completed, the reaction was cooled to room temperature, and a vacuum pump was used for reduced pressure distillation to obtain a PAI precursor, 6kgPAI precursor, 0.5kg dicyclohexylcarbodiimide, 5.5kg toluene diisocyanate and 21kg diisocyanate were introduced into a mixing kettle, and stirred at 60rpm to obtain component B;

[0037] S3. 10 kg of component A and 10 kg of component B were introduced into a reaction kettle, the reaction system was heated to 65° C., and stirred at a speed of 150 rpm for 4 hours to obtain a solvent-free PU resin.

[0038] Example 4

[0039] A production process of solvent-free PU resin comprises the following steps:

[0040] S1. Pump 6 kg of ethyl 2-bromoisobutyrate and 10 kg of N, N-dimethylformamide into a reactor, stir to dissolve and degas, then introduce nitrogen protection, add 0.5 kg of copper bromide and 0.4 kg of pentamethyldiethylenetriamine under nitrogen atmosphere, prepare 30 wt% styrene sulfonic acid monomer solution with N, N-dimethylformamide, heat the reaction system to 90 ° C, slowly add 30 kg of styrene sulfonic acid monomer solution, and keep warm after the addition is completed. The reaction was continued for 6 hours. After the reaction was completed, the PSSA homopolymer was obtained by distillation under reduced pressure. 10 kg of PSSA homopolymer, 46 kg of polyethylene adipate glycol, 13 kg of polytetrahydrofuran diol, 3 kg of diphenylmethane, 5 kg of castor oil, 0.08 kg of organic bismuth, 0.08 kg of antioxidant 1010, 10 kg of glycerol and 0.7 kg of γ-aminopropyltriethoxysilane were introduced into a mixing kettle and stirred at a speed of 100 rpm to obtain component A.

[0041] S2, 6kgN-methacrylimide and 10kgN,N-dimethylformamide were pumped into the reactor, degassed using a degasser, nitrogen was introduced, 0.9kg of azobisisobutyronitrile was added under nitrogen protection, the temperature was raised to 80°C, the reaction was stirred at a speed of 100rpm for 8h, the temperature was lowered to room temperature, 0.1kg of ethanolamine was added under nitrogen protection, the reaction was stirred at 50°C for 4h, after the reaction was completed, the reaction was cooled to room temperature, and a vacuum pump was used for reduced pressure distillation to obtain a PAI precursor, 7kgPAI precursor, 0.6kg dicyclohexylcarbodiimide, 6kg toluene diisocyanate and 22kg diisocyanate were introduced into a mixing kettle, and stirred at a speed of 100rpm to obtain component B;

[0042] S3. 10 kg of component A and 10 kg of component B were introduced into a reaction kettle, the reaction system was heated to 70° C., and stirred at a speed of 200 rpm for 5 hours to obtain a solvent-free PU resin.

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that no PSSA homopolymer is added, and the remaining steps are the same as those in Example 1.

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 2 is that no PAI precursor is added, and the remaining steps are the same as Example 2.

[0047] Comparative Example 3

[0048] The difference between this comparative example and Example 3 is that PSSA homopolymer and PAI precursor are not added, and the remaining steps are the same as Example 3.

[0049] Comparative Example 4

[0050] The difference between this comparative example and Example 4 is that no PSSA homopolymer and PAI precursor are added, and the remaining steps are the same as Example 4.

[0051] The physical properties of the solvent-free PU resins prepared in Examples 1-4 and Comparative Examples 1-4 were measured.

[0052] (Ⅰ) Viscosity: According to GB / T 2794-2022 "Determination of viscosity of adhesives", the viscometer used is NDJ-1 and the measurement temperature is 20℃.

[0053] (II) Moisture: According to GB / T 6284-2006 “General method for determination of moisture in chemical products - loss on drying method”.

[0054] (III) Surface drying time: According to GB / T 16777-2008 "Test methods for building waterproof coatings", the coating dosage is 0.5kg / m 2 , the measured temperature is 23℃ and the humidity is 50%.

[0055] (IV) Tensile strength and elongation at break: According to 16777-2008 “Test methods for building waterproof coatings”, the tensile strength test shall be conducted at a tensile speed of 500 mm / min, and the elongation at break shall be conducted at a tensile speed of 450 mm / min.

[0056] (V) Hardness: According to GB / T 531.1-2008 “Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore durometer method (Shore hardness)”.

[0057] The test results are shown in Table 1:

[0058] Table 1. Physical properties of Examples 1-4 and Comparative Examples 1-4

[0059]

[0060] As shown in Table 1, the viscosity of Examples 1-4 is relatively high, and the viscosity of Comparative Examples 1-4 is relatively low, which may be due to the lack of PSSA homopolymer and / or PAI precursor, resulting in a decrease in the molecular chain length and crosslinking degree of the resin, thereby affecting the viscosity. The moisture content of Examples 1-4 and Comparative Examples 1-4 is relatively low, and the difference is not large. The surface drying time of Examples 1-4 is 4 hours, indicating that the drying performance of the resin is relatively stable. The surface drying time of Comparative Examples 1-4 is extended to 5 or 6 hours, indicating that the curing speed of the resin is slowed down. The tensile strength and elongation at break of Examples 1-4 are both high, and the difference is not large, indicating that the resin has good mechanical properties and toughness. The tensile strength and elongation at break of Comparative Examples 1-4 are significantly reduced, which may be due to the lack of PSSA homopolymer and / or PAI precursor, resulting in changes in the molecular chain structure and crosslinking density of the resin, thereby affecting its mechanical properties and toughness. The hardness of Examples 1-4 is between 64-65 degrees, indicating that the hardness of the resin is relatively stable. The hardness of Comparative Examples 1-4 is relatively low, which may be related to the molecular chain structure and cross-linking degree of the resin.

[0061] In Examples 1-4, due to the mixing of PSSA homopolymer and polyol and the reaction of PAI precursor and isocyanate, the PSSA homopolymer acts as the skeleton structure of the resin. The PSSA homopolymer is mixed with other polyols to extend the polymer chain and increase the complexity of the chain, which may improve the tensile strength, elongation at break and hardness of the resin obtained in Examples 1-4. In addition, a large number of crosslinking points may exist in the resin obtained in Examples 1-4, which restricts the movement of the molecular chain and improves the thermal stability and mechanical properties.

[0062] In summary, the solvent-free PU resins prepared in Examples 1-4 have higher mechanical strength and thermal stability, and also have certain fluidity.

[0063] In the description of the specification, the description with reference to the terms "embodiment", "various embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or preparation example are included in at least one embodiment or preparation example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or preparation example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or preparation examples in a suitable manner.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A production process of solvent-free PU resin, characterized in that: The following steps are involved: S1. Pump ethyl 2-bromoisobutyrate and N,N-dimethylformamide into a reaction kettle, add copper bromide and pentamethyldiethylenetriamine under a nitrogen atmosphere, heat the reaction system, slowly dropwise add the styrene sulfonic acid monomer solution, and after the dropwise addition is completed, heat and react. After the reaction is completed, perform vacuum distillation to obtain a PSSA homopolymer, and pass the PSSA homopolymer, polyester polyol, polyether polyol, diphenylmethane, castor oil, organic bismuth, antioxidant 1010, glycerol and γ-aminopropyltriethoxysilane into a mixing kettle, stir evenly, and obtain component A; S2, pumping N-methylacrylimide and N,N-dimethylformamide into a reaction kettle, adding azobisisobutyronitrile under nitrogen protection, heating the reaction system, stirring the reaction, cooling to room temperature after the reaction, adding ethanolamine, stirring the reaction at room temperature or 30-50°C for 2-4h, and distilling under reduced pressure to obtain a PAI precursor, and passing the PAI precursor, dicyclohexylcarbodiimide, toluene diisocyanate and diisocyanate into a mixing kettle, stirring evenly, to obtain component B; S3. Add component A and component B into a reaction kettle, heat the reaction system, and stir for 1-5 hours to obtain a solvent-free PU resin.

2. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S1, the feed mass ratio of ethyl 2-bromoisobutyrate, N,N-dimethylformamide, copper bromide, pentamethyldiethylenetriamine and styrene sulfonic acid monomer solution is (4-6):10:(0.1-0.5):(0.3-0.4):(20-30).

3. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S1, the temperature of the reaction system is raised to 80-90° C., and the insulation reaction time is 4-6 hours.

4. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S1, the mass ratio of PSSA homopolymer, polyester polyol, polyether polyol, diphenylmethane, castor oil, organic bismuth, antioxidant 1010, glycerol and γ-aminopropyltriethoxysilane is (8-10): (44-46): (10-13): (1-3): (4-5): (0.06-0.08): (0.06-0.08): (8-10): (0.6-0.7).

5. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S1, the polyester polyol includes one or more of polyethylene terephthalate diol, polypropylene terephthalate diol, polybutylene terephthalate diol and polyethylene adipate diol, and the polyether polyol includes one or more of polypropylene glycol, polybutylene glycol and polytetramethylene glycol.

6. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S2, the feed mass ratio of N-methylacrylimide, N,N-dimethylformamide, azobisisobutyronitrile and ethanolamine is (3-6):10:(0.5-0.9):(0.03-0.1).

7. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S2, the feed mass ratio of PAI precursor, dicyclohexylcarbodiimide, toluene diisocyanate and diisocyanate is (5-7): (0.2-0.6): (4-6): (18-22).

8. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S2, the temperature of the reaction system is raised to 60-80° C., and the stirring reaction time is 4-8 hours.

9. The production process of a solvent-free PU resin according to claim 1, characterized in that: In step S3, the temperature of the reaction system is raised to 60-70°C.

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