Super-high-functionality light-cured polyurethane resin and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane materials, in particular to super-high-functionality light-cured polyurethane resin and a preparation method thereof. The adhesive is prepared from the following components in parts by weight: 30 to 40 parts of polypropylene oxide glycol, 25 to 35 parts of modified polyethylene glycol, 50 to 65 parts of isocyanate, 2 to 5 parts of triethylamine, 10 to 15 parts of epoxy resin, 1 to 3 parts of hydroxycyclohexane benzophenone and 0.2 to 1 part of dibutyltin dilaurate. The prepared light-cured polyurethane resin has good thermal stability and chemical stability, and can keep stable performance in a wide temperature range and in various chemical media.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane materials, and in particular to an ultra-high functionality photocurable polyurethane resin and a preparation method thereof. Background Art

[0002] Photocurable polyurethane resin can be quickly cured under ultraviolet light to become a material with high strength and good transparency. The characteristic of photocurable polyurethane resin is that it contains two or more functional groups in its molecular chain. Through the action of photoinitiator, these functional groups can be cross-linked, so that the polyurethane can be cured within a few seconds. In addition, photocurable polyurethane resin is a solvent-free system and does not contain any volatile organic compounds, so it is environmentally friendly. Its cross-linked structure also improves the physical properties and chemical stability of the material, making it have good heat resistance and light resistance. Due to its excellent comprehensive performance, photocurable polyurethane resin is widely used in photocurable coatings, photocurable inks, photocurable adhesives and photoresists.

[0003] In the prior art, light-curing polyurethane resin is a heat-sensitive material. When the ambient temperature rises, the mobility of its molecular chain increases, causing the material to soften and deform. In addition, the wear resistance of light-curing polyurethane resin is not high and cannot meet the needs of long-term use. At the same time, light-curing polyurethane resin will shrink during the polymerization process, affecting the performance and service life of the product. Summary of the invention

[0004] In order to solve the problems mentioned in the above background technology, the present invention provides an ultra-high functionality photocurable polyurethane resin and a preparation method thereof.

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

[0006] An ultra-high functionality light-curing polyurethane resin comprises, by weight, 30-40 parts of polyoxypropylene glycol, 25-35 parts of modified polyethylene glycol, 50-65 parts of isocyanate, 2-5 parts of triethylamine, 10-15 parts of epoxy resin, 1-3 parts of hydroxycyclohexane phenone and 0.2-1 part of dibutyltin dilaurate.

[0007] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned ultra-high functionality photocurable polyurethane resin, comprising the following steps:

[0008] S1. Weigh modified polyethylene glycol, triethylamine, isocyanate, epoxy resin and hydroxycyclohexane phenone in parts by weight, add them into a reaction kettle, add dibutyltin dilaurate, heat and stir to react, and obtain a prepolymer.

[0009] S2. pouring the prepolymer into a preheated mold and placing it in an oven for curing to obtain an ultra-high functionality photocurable polyurethane resin.

[0010] Furthermore, in step S1, the heating temperature is 60-70° C., the stirring speed is 50-100 rpm, and the reaction time is 2-4 h.

[0011] Furthermore, the modified polyethylene glycol in step S1 is prepared by the following steps:

[0012] In a reactor equipped with a magnetic stirrer and a constant temperature water bath, replace the environment with nitrogen to an anhydrous and oxygen-free environment, add polyethylene glycol and anhydrous dichloromethane, heat to 40-50°C, stir until completely dissolved, add N-methylmaleimide and 4-dimethylaminopyridine, maintain the reaction temperature at 40-45°C, stir the reaction for 12-24 hours, and after the reaction is completed, add succinic anhydride to the above reaction solution, continue to stir the reaction for 6-12 hours, so that the anhydride group of succinic anhydride and the remaining hydroxyl or amino group undergo esterification reaction, and after the reaction is completed, pour the reaction solution into ice water for precipitation, filter to obtain a solid product, wash with anhydrous ethanol 3-5 times, and dry in a vacuum drying oven at 40-50°C for 24-48 hours to obtain modified polyethylene glycol.

[0013] Furthermore, in step S2, the mold is preheated to 60-70°C.

[0014] Furthermore, the curing method in step S2 is: first curing at 80-100° C. for 4-6 hours, and then heating to 120-130° C. for curing for 2-3 hours.

[0015] Further, the isocyanate in step S2 includes one or more of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

[0016] Furthermore, the mass ratio of polyethylene glycol, anhydrous dichloromethane, N-methylmaleimide, 4-dimethylaminopyridine and succinic anhydride is (5-6):10:(2-3):(0.05-0.1):(1.5-2).

[0017] Beneficial effects of the present invention:

[0018] 1. The polymer chain of the photocurable polyurethane resin prepared by the present invention is composed of alternating polyurethane hard segments and polyether soft segments. The polyurethane hard segment is composed of urethane groups generated by the reaction of isocyanate and polyoxypropylene glycol, and has high rigidity and strength. The polyether soft segment is mainly composed of polyethylene glycol and its derivatives, and has good flexibility and elasticity. During the photocuring process, the carbon-carbon double bonds in the prepolymer molecular chain undergo free radical polymerization under the action of the photoinitiator to form a three-dimensional network structure, so that the photocurable polyurethane resin has excellent mechanical properties, thermal stability and chemical stability. The introduction of modified polyethylene glycol introduces additional functional groups into the polyurethane resin molecular chain, increases the reactivity of the molecular chain, and provides more interaction sites for it, which helps to form a more compact and stable cross-linked network structure. The three-dimensional network structure of the photocurable polyurethane resin makes it have high strength and hardness. At the same time, the introduction of the polyether soft segment gives it good flexibility and elasticity, so that the photocurable polyurethane resin can show excellent mechanical properties when subjected to external forces, such as high tensile strength, high tear strength and good resilience. In addition, the formation of a cross-linked network structure makes the molecular chain of the photocurable polyurethane resin tighter and more stable, less susceptible to the influence of the external environment, has good thermal stability and chemical stability, and can maintain stable performance in a wide temperature range and in a variety of chemical media. DETAILED DESCRIPTION

[0019] 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.

[0020] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0021] Preparation Example 1

[0022] The modified polyethylene glycol comprises the following steps to prepare:

[0023] In a reactor equipped with a magnetic stirrer and a constant temperature water bath, replace the atmosphere with nitrogen to an anhydrous and oxygen-free environment, add 50 g of polyethylene glycol and 100 g of anhydrous dichloromethane, heat to 40°C, stir until completely dissolved, add 20 g of N-methylmaleimide and 0.5 g of 4-dimethylaminopyridine, maintain the reaction temperature at 40°C, stir the reaction for 12 hours, and after the reaction is completed, add 15 g of succinic anhydride to the above reaction solution, continue stirring the reaction for 6 hours, and after the reaction is completed, pour the reaction solution into ice water for precipitation, filter to obtain a solid product, wash it 3 times with anhydrous ethanol, and dry it in a vacuum drying oven at 40°C for 24 hours to obtain modified polyethylene glycol.

[0024] Preparation Example 2

[0025] The modified polyethylene glycol comprises the following steps to prepare:

[0026] In a reactor equipped with a magnetic stirrer and a constant temperature water bath, replace the atmosphere with nitrogen to an anhydrous and oxygen-free environment, add 55 g of polyethylene glycol and 100 g of anhydrous dichloromethane, heat to 45°C, stir until completely dissolved, add 25 g of N-methylmaleimide and 0.7 g of 4-dimethylaminopyridine, maintain the reaction temperature at 42°C, stir the reaction for 18 hours, and after the reaction is completed, add 17.5 g of succinic anhydride to the reaction solution, continue stirring the reaction for 8 hours, and after the reaction is completed, pour the reaction solution into ice water for precipitation, filter to obtain a solid product, wash it 4 times with anhydrous ethanol, and dry it in a vacuum drying oven at 45°C for 36 hours to obtain modified polyethylene glycol.

[0027] Preparation Example 3

[0028] The modified polyethylene glycol comprises the following steps to prepare:

[0029] In a reactor equipped with a magnetic stirrer and a constant temperature water bath, replace the atmosphere with nitrogen to an anhydrous and oxygen-free environment, add 60 g of polyethylene glycol and 100 g of anhydrous dichloromethane, heat to 50°C, stir until completely dissolved, add 30 g of N-methylmaleimide and 1 g of 4-dimethylaminopyridine, maintain the reaction temperature at 45°C, stir the reaction for 24 hours, and after the reaction is completed, add 20 g of succinic anhydride to the reaction solution, continue stirring the reaction for 12 hours, and after the reaction is completed, pour the reaction solution into ice water for precipitation, filter to obtain a solid product, wash it 5 times with anhydrous ethanol, and dry it in a vacuum drying oven at 50°C for 48 hours to obtain modified polyethylene glycol.

[0030] Example 1

[0031] A method for preparing an ultra-high functionality photocurable polyurethane resin comprises the following steps:

[0032] S1. Weigh 30 parts of polyoxypropylene glycol, 25 parts of modified polyethylene glycol obtained in Preparation Example 1, 2 parts of triethylamine, 50 parts of isophorone diisocyanate, 10 parts of epoxy resin and 1 part of hydroxycyclohexane phenone by weight, add them into a reaction kettle, add 0.2 parts of dibutyltin dilaurate, heat to 60°C, stir and react at a speed of 50 rpm for 2 hours to obtain a prepolymer.

[0033] S2. Pour the prepolymer into a mold preheated to 60°C, put it into an oven, first cure it at 80°C for 4 hours, then heat it to 120°C for 2 hours, and obtain an ultra-high functionality photocurable polyurethane resin.

[0034] Example 2

[0035] A method for preparing an ultra-high functionality photocurable polyurethane resin comprises the following steps:

[0036] S1. Weigh 35 parts of polyoxypropylene glycol, 30 parts of modified polyethylene glycol obtained in Preparation Example 2, 3 parts of triethylamine, 60 parts of isophorone diisocyanate, 12 parts of epoxy resin and 2 parts of hydroxycyclohexane phenone in parts by weight, add them into a reaction kettle, add 0.5 parts of dibutyltin dilaurate, heat to 65° C., stir and react at a speed of 60 rpm for 3 hours to obtain a prepolymer.

[0037] S2. Pour the prepolymer into a mold preheated to 65°C, put it into an oven, first cure it at 90°C for 5 hours, then heat it to 125°C for 2.5 hours to obtain an ultra-high functionality photocurable polyurethane resin.

[0038] Example 3

[0039] A method for preparing an ultra-high functionality photocurable polyurethane resin comprises the following steps:

[0040] S1. Weigh 40 parts of polyoxypropylene glycol, 35 parts of modified polyethylene glycol obtained in Preparation Example 3, 5 parts of triethylamine, 65 parts of isophorone diisocyanate, 15 parts of epoxy resin and 3 parts of hydroxycyclohexane phenone in parts by weight, add them into a reaction kettle, add 1 part of dibutyltin dilaurate, heat to 70°C, stir and react at a speed of 100 rpm for 4 hours to obtain a prepolymer.

[0041] S2. Pour the prepolymer into a mold preheated to 70°C, put it into an oven, first cure it at 100°C for 6 hours, then heat it to 130°C for 3 hours, and obtain an ultra-high functionality photocurable polyurethane resin.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 1 is that polyethylene glycol is used instead of the modified polyethylene glycol prepared in Preparation Example 1, and the remaining steps are the same as those in Example 1.

[0044] Comparative Example 2

[0045] The difference between this comparative example and Example 2 is that N-methylmaleimide is used instead of the modified polyethylene glycol prepared in Preparation Example 2, and the remaining steps are the same as those in Example 2.

[0046] Comparative Example 3

[0047] The difference between this comparative example and Example 3 is that succinic anhydride is used instead of the modified polyethylene glycol prepared in Preparation Example 3, and the remaining steps are the same as those in Example 3.

[0048] (I) Mechanical property test: At room temperature, the polyurethane resins prepared in Examples 1-3 and Comparative Examples 1-3 were respectively taken to make samples of 35 mm×5 mm×3 mm, and placed in a tensile tester (AGS-X) at a tensile speed of 100 mm / min.

[0049] (II) Thermal stability test: 10 mg of each sample prepared in Examples 1-3 and Comparative Examples 1-3 were placed in a crucible of a thermogravimetric analyzer, and the temperature was set from room temperature to 800° C. at a heating rate of 10° C. / min.

[0050] (III) Glass transition temperature test: 10 mg of each sample prepared in Examples 1-3 and Comparative Examples 1-3 were placed in an aluminum pan of a differential scanning calorimeter. Under nitrogen protection, the temperature was set from room temperature to 180°C at a heating rate of 10°C / min.

[0051] (IV) UV aging test: The polyurethane resins prepared in Examples 1-3 and Comparative Examples 1-3 were respectively taken to prepare samples of 10 mm×10 mm×2 mm, placed in a UV aging test chamber (40 W, UVA-340, 25° C., 60% RH), and aged for 48 h.

[0052] The test results of each group are shown in Table 1:

[0053] Table 1. Test results of Examples 1-3 and Comparative Examples 1-3

[0054]

[0055] As can be seen from Table 1, the fracture strengths of Examples 1-3 are all higher than those of Comparative Examples 1-3. The polyurethane resin prepared in the examples may form a more compact and tough network structure, so that when stretched by external force, it can more effectively disperse stress, thereby improving the fracture strength of the resin. In contrast, Comparative Example 1 uses unmodified polyethylene glycol, which has low functionality and reactivity, resulting in a relatively loose network structure and low fracture strength. Comparative Examples 2 and 3 use N-methylmaleimide and succinic anhydride instead of modified polyethylene glycol, respectively, which may have weaker ability to form a network structure, so the fracture strength is also low.

[0056] The thermal stability of Examples 1-3 is significantly better than that of Comparative Examples 1-3. The modified polyethylene glycol may be able to improve the thermal stability of the resin, making it less likely to decompose at high temperatures. However, the thermal stability of Comparative Examples 1-3 is poor.

[0057] The glass transition temperature is the temperature at which a resin changes from a glassy state to a rubbery state, and is an important indicator for evaluating the heat resistance of a resin. The glass transition temperatures of Examples 1-3 are all higher than those of Comparative Examples 1-3. Modified polyethylene glycol may increase the glass transition temperature of the resin by increasing the crosslinking density and intermolecular forces of the resin. The glass transition temperatures of Comparative Examples 1-3 are relatively low, indicating that they are more susceptible to deformation and softening at higher temperatures, and have poor heat resistance.

[0058] The UV aging test simulates the situation that the resin is exposed to UV rays during long-term outdoor use. The appearance of Examples 1-3 did not change significantly after the UV aging test, while Comparative Examples 1-3 showed slight yellowing. This shows that the UV aging resistance of Examples 1-3 is better than that of Comparative Examples 1-3.

[0059] In summary, the introduction of modified polyethylene glycol prepared in Preparation Examples 1-3 significantly improved the mechanical properties, thermal stability, heat resistance and UV aging resistance of the photocurable polyurethane resin prepared in Examples 1-3, and improved the comprehensive performance of the photocurable polyurethane resin.

[0060] In the description of the specification, the description with reference to the terms "preparation example", "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.

[0061] 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. An ultra-high functionality photocurable polyurethane resin, characterized in that: The invention comprises, by weight: 30-40 parts of polyoxypropylene glycol, 25-35 parts of modified polyethylene glycol, 50-65 parts of isocyanate, 2-5 parts of triethylamine, 10-15 parts of epoxy resin, 1-3 parts of hydroxycyclohexane phenone and 0.2-1 parts of dibutyltin dilaurate.

2. The method for preparing the ultra-high functionality photocurable polyurethane resin according to claim 1, characterized in that: The method comprises the following steps: S1. Weigh polyoxypropylene glycol, modified polyethylene glycol, triethylamine, isocyanate, epoxy resin and hydroxycyclohexane phenone in parts by weight, add them into a reaction kettle, add dibutyltin dilaurate, heat and stir to react, and obtain a prepolymer; S2. pouring the prepolymer into a preheated mold and placing it in an oven for curing to obtain an ultra-high functionality photocurable polyurethane resin.

3. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 2, characterized in that: In step S1, the heating temperature is 60-70° C., the stirring speed is 50-100 rpm, and the reaction time is 2-4 h.

4. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 2, characterized in that: The modified polyethylene glycol in step S1 is prepared by the following steps: In an anhydrous and oxygen-free environment, polyethylene glycol and anhydrous dichloromethane are added to a reactor, heated to 40-50°C, stirred until completely dissolved, N-methylmaleimide and 4-dimethylaminopyridine are added, kept at 40-45°C, stirred for reaction for 12-24 hours, and after the reaction is completed, succinic anhydride is added, and the stirring reaction is continued for 6-12 hours. After the reaction is completed, the reaction solution is poured into ice water for precipitation, filtered to obtain a solid product, washed, and dried to obtain modified polyethylene glycol.

5. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 2, characterized in that: In step S2, the mold is preheated to 60-70°C.

6. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 2, characterized in that: The curing method in step S2 is: firstly curing at 80-100° C. for 4-6 hours, and then heating to 120-130° C. for curing for 2-3 hours.

7. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 2, characterized in that: The isocyanate in step S1 includes one or more of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

8. The method for preparing a super-high functionality photocurable polyurethane resin according to claim 4, characterized in that: The mass ratio of polyethylene glycol, anhydrous dichloromethane, N-methylmaleimide, 4-dimethylaminopyridine and succinic anhydride is (5-6):10:(2-3):(0.05-0.1):(1.5-2).

Images