A hindered amine light stabilizer and a method for preparing the same

Abstract

The application provides a hindered amine light stabilizer and a preparation method thereof, and the preparation method comprises the following steps: putting N, N-bis(2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine and an organic solvent into a reaction bottle, heating to 50-80 DEG C, adding methyl acrylate into the system dropwise, obtaining an intermediate I through an addition reaction, and then obtaining a crude product through an ester exchange reaction of the intermediate I and tetramethylpiperidinol in the presence of a catalyst and an organic solvent, washing with water, decoloring, filtering, cooling and crystallizing, filtering and drying to obtain the product; the light stabilizer obtained by the application has multiple hindered amine functional groups, has good heat resistance and extraction resistance, and has good compatibility with resin.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of polymer material modification aids, and particularly relates to a hindered amine light stabilizer and a preparation method thereof. BACKGROUND

[0002] The hindered amine light stabilizer (HALS) is a kind of compound taking 2,2,6,6-tetramethylpiperidine as a mother body. Because it contains a piperidine group, and two methyl groups are connected to the carbon atoms on the two sides of the nitrogen atom of the piperidine group, and the group connected to the nitrogen atom is hindered by the two side groups, it is called the hindered amine light stabilizer. The general formula of the molecular structure is as follows:

[0003] ,

[0004] wherein R is H, a substituted alkyl group or a substituted alkoxy group, and A is an auxiliary group connected to the hindered piperidine group.

[0005] Among various light stabilizers, the hindered amine light stabilizer (HALS) has better light stabilizing efficiency, and is particularly suitable for high molecular materials such as polyolefin, polystyrene and polyurethane. The stabilizing effect is several times higher than that of the ultraviolet absorber, and has a good synergistic effect with other additives, so it becomes the mainstream of international research and development and the main variety in the light stabilizer market.

[0006] Researches show that the double hindered piperidine is more effective than the single piperidine group hindered amine light stabilizer, and the main reason is that the functional group density of the double hindered piperidine group hindered amine light stabilizer is larger, and the efficiency is higher. On the other hand, the double piperidine group hindered amine light stabilizer can also be grafted on the high molecular chain in the light protection, thereby reducing the loss due to extraction, migration, volatilization and the like, thereby increasing the efficiency. SUMMARY

[0007] The purpose of the application is to obtain a multi-piperidine hindered amine light stabilizer, which not only can solve the problem of low use efficiency of the single piperidine hindered amine light stabilizer, but also expands the types of the hindered amine light stabilizer, and has good application prospect and economic benefit.

[0008] To solve the above problems, the application discloses a hindered amine light stabilizer and a preparation method thereof.

[0009] To achieve the above purpose, the technical scheme of the application is as follows:

[0010] A hindered amine light stabilizer and a preparation method thereof, the structural formula of which is as follows:

[0011] ;

[0012] The preparation method comprises the following steps:

[0013] Step one: Put N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine and organic solvent into the reaction bottle, and heat to 50-80℃, then add methyl acrylate dropwise into the system, continue to heat to 60-90℃ for 6-24 hours after the dropwise addition is completed. After the reaction is completed, the excess methyl acrylate and organic solvent are evaporated, and the intermediate I is obtained. The reaction is as follows:

[0014] ;

[0015] Step two: add organic solvent into the intermediate I system to reflux and separate water for a period of time. After the water content in the system is reduced to below 0.1%, the system is cooled to below 80℃, then tetramethylpiperidinol and a catalyst are added into the system, and the system is heated to 90-160℃ for 12-48 hours to obtain a crude product. The crude product is washed with water, decolorized, filtered, the filtrate is cooled to below 50℃, filtered, and dried at 60-120℃ to obtain a white solid. The reaction is as follows:

[0016] .

[0017] Preferably, the molar ratio of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine to methyl acrylate in step one is 1:2-4.

[0018] Preferably, the amount of the organic solvent used in step one is 1-4 times the mass of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine.

[0019] Preferably, the molar ratio of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine to tetramethylpiperidinol in step two is 1:1.9-3.

[0020] Preferably, the amount of the catalyst used in step two is 0.1%-3% of the mass of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine.

[0021] Preferably, the amount of the organic solvent used in step two is 2-10 times the mass of tetramethylpiperidinol.

[0022] Preferably, the amount of water used in step two is 1-5 times the mass of tetramethylpiperidinol.

[0023] Preferably, the organic solvent used in step one is any one of methanol, ethanol, and isopropanol.

[0024] Preferably, the catalyst used in step two is any one of sodium methoxide, lithium amide, tetraethyl titanate, tetrabutyl titanate, isopropyl titanate, and organotin.

[0025] Preferably, the organic solvent in step two is any one of petroleum ether, n-heptane, n-octane, toluene, xylene, mesitylene.

[0026] The present application has the following advantages:

[0027] The hindered amine light stabilizer of the present application belongs to monomeric hindered amine light stabilizer. Compared with conventional monomeric hindered amine light stabilizer, the light stabilizer has larger relative molecular mass and higher efficiency under the same mass. It has good compatibility with resin, no coloration, low toxicity and good light stabilizing effect. As a high-efficiency light stabilizer, it can be applied to PP, PE, PVC, PS, ABS resin and other materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The weather resistance of the light stabilizer obtained by the present application and light stabilizer 770 in PP monofilament. DETAILED DESCRIPTION

[0029] The present application will be further illustrated by the following drawings and specific embodiments, and it should be understood that the following specific embodiments are only used to illustrate the present application and not to limit the scope of the present application. Example 1

[0030] Weigh 39.5 g of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine and 100 g of methanol into a reaction bottle, heat to 60°C until the solid is completely dissolved, then add 18.94 g of methyl acrylate to the system, heat to 65°C and react for 8 hours. After the reaction is completed, remove the excess methyl acrylate and methanol under reduced pressure to obtain a light yellow oil, which is intermediate I.

[0031] Then add 150 g of petroleum ether to the intermediate I system, reflux and remove water for 3 hours, then cool to 60°C, add 31.4 g of tetramethylpiperidinol and 0.4 g of sodium methoxide, continue to heat to 120°C and react for 20 hours, then cool to 80°C, add 100 g of hot water three times, decolorize, filter, cool to 30°C, filter and dry to obtain a white solid with a yield of 90.5%. Example 2

[0032] Weigh 79 g of N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine and 200 g of ethanol into a reaction bottle, heat to 60°C until the solid is completely dissolved, then add 41.32 g of methyl acrylate to the system, heat to 70°C and react for 10 hours. After the reaction is completed, remove the excess methyl acrylate and ethanol under reduced pressure.

[0033] To the system of intermediate I, 200 g of n-octane was added, and water was removed by reflux for 2 hours until the water content was reduced to 0.05%. Then the temperature was lowered to 70°C, 64.05 g of tetramethylpiperidinol and 1 g of tetrabutyl titanate were added, and the temperature was raised to 125°C for 30 hours. The temperature was lowered to 80°C, 120 g of hot water was added for washing three times, and the product was decolorized and filtered. The white solid was obtained by lowering the temperature to 20°C and filtering, and the yield was 92.35%. Example 3

[0034] 79 g of N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl) 1,6-hexanediamine and 200 g of methanol were weighed into a reaction bottle, and the temperature was raised to 60°C until the solid was completely dissolved. Then 41.32 g of methyl acrylate was added dropwise to the system, and the temperature was raised to 62°C for 10 hours. After the reaction was completed, the excess methyl acrylate and methanol were removed by evaporation under reduced pressure.

[0035] To the system of intermediate I, 200 g of n-heptane was added, and water was removed by reflux for 2 hours until the water content was reduced to 0.07%. Then the temperature was lowered to 75°C, 64.05 g of tetramethylpiperidinol and 1 g of tetrabutyl titanate were added, and the temperature was raised to 98°C for 35 hours. The temperature was lowered to 80°C, 120 g of hot water was added for washing three times, and the product was decolorized and filtered. The white solid was obtained by lowering the temperature to 20°C and filtering, and the yield was 88.32%. Example 4

[0036] 118.5 g of N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl) 1,6-hexanediamine and 250 g of ethanol were weighed into a reaction bottle, and the temperature was raised to 60°C until the solid was completely dissolved. Then 61.98 g of methyl acrylate was added dropwise to the system, and the temperature was raised to 70°C for 12 hours. After the reaction was completed, the excess methyl acrylate and ethanol were removed by evaporation under reduced pressure.

[0037] To the system of intermediate I, 300 g of n-octane was added, and water was removed by reflux for 3 hours until the water content was reduced to 0.09%. Then the temperature was lowered to 60°C, 98.91 g of tetramethylpiperidinol and 1.5 g of dibutyl tin oxide were added, and the temperature was raised to 125°C for 40 hours. The temperature was lowered to 70°C, 200 g of hot water was added for washing three times, and the product was decolorized and filtered. The white solid was obtained by lowering the temperature to 30°C and filtering, and the yield was 90.11%. Example 5

[0038] 118.5 g of N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl) 1,6-hexanediamine and 250 g of ethanol were weighed into a reaction bottle, and the temperature was raised to 60°C until the solid was completely dissolved. Then 61.98 g of methyl acrylate was added dropwise to the system, and the temperature was raised to 70°C for 12 hours. After the reaction was completed, the excess methyl acrylate and ethanol were removed by evaporation under reduced pressure.

[0039] Then 300g petroleum ether was added into the system of intermediate I, and water was removed by refluxing for 3 hours until the water content was reduced to 0.09%. Then the temperature was lowered to 60℃, 98.91g tetramethylpiperidinol and 1.5g tetraethyl titanate were added, and the temperature was raised to 120℃ and reacted for 40 hours. Then the temperature was lowered to 70℃, 200g hot water was added and washed for 3 times, and then decolorized and filtered. The white solid was obtained by lowering the temperature to 30℃ and filtering, and the yield was 93.48%. Example 6

[0040] The hindered amine light stabilizer obtained in Example 1 was compared with light stabilizer 770, and both were added into polypropylene monofilament respectively.

[0041] 1. The formula is as follows:

[0042]

[0043] Test conditions:

[0044] UV accelerated aging conditions: UVB-313, irradiation intensity 0.71 W / (m2·nm), blackboard temperature (light) 60℃, blackboard temperature (dark) 50℃, light 480 minutes + condensation 240 minutes; test time: 100, 200, 300 hours.

[0045] Experimental data analysis:

[0046] Results refer to Figure 1 As shown in the table, the weather resistance of the light stabilizer obtained by the present application in the PP monofilament is better than that of light stabilizer 770.

[0047] It should be noted that the above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. For ordinary skilled persons in the technical field, they can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements fall within the protection scope of the claims of the present application.

Claims

1. A process for the preparation of a hindered amine light stabilizer, characterized in that, The structure of the hindered amine light stabilizer is shown in the following formula (1): ； The preparation method comprises the following steps: Step one: put N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine and organic solvent into a reaction bottle, heat to 50-80 DEG C, drop methyl acrylate into the system, continue to heat to 60-90 DEG C after dropping, react for 6-24 hours, evaporate excess methyl acrylate and organic solvent after reaction, obtain intermediate I, and the reaction is shown as follows: ； Step two: add organic solvent to intermediate I, reflux and remove water for a period of time, then reduce the water content in the system to below 0.1%, and then reduce the temperature to below 80 DEG C, then add tetramethylpiperidinol and catalyst, heat to 90-160 DEG C, react for 12-48 hours to obtain a crude product, wash the crude product with water, decolorize, filter, cool the filtrate to below 50 DEG C, filter, and dry at 60-120 DEG C to obtain a white solid, and the reaction is shown as follows: ； The amount of the organic solvent in step one is 1-4 times the mass of the N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine; and the catalyst in step two is any one of sodium methoxide, lithium amide, tetraethyl titanate, tetrabutyl titanate, isopropyl titanate and organotin.

2. The process for the preparation of a hindered amine light stabilizer according to claim 1, characterized in that, The molar ratio of the N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine to the methyl acrylate in step one is 1:2-4.

3. The method of preparing a hindered amine light stabilizer according to claim 1, wherein The molar ratio of the N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine to the tetramethylpiperidinol in step two is 1:1.95-3.

4. The method of preparing a hindered amine light stabilizer according to claim 1, wherein The amount of the catalyst in step two is 0.1%-3% of the mass of the N, N-bis (2, 2, 6, 6-tetramethyl-4-piperidyl) 1, 6-hexanediamine, and the amount of the organic solvent is 2-10 times the mass of the tetramethylpiperidinol.

5. The method of preparing a hindered amine light stabilizer according to claim 1, wherein The amount of the water used in step two is 1-5 times the mass of the tetramethylpiperidinol.

6. The method of preparing a hindered amine light stabilizer according to claim 1, wherein The organic solvent in step one is any one of methanol, ethanol and isopropanol.

7. The method for preparing a hindered amine light stabilizer as described in claim 1, characterized in that, The organic solvent in step two is any one of petroleum ether, n-heptane, n-octane, cyclohexane, methylcyclohexane, toluene, xylene, mesitylene and chlorobenzene.

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