Space hindering adjustable weak base light stabilizer, preparation method and application thereof

Abstract

The application is a divisional application of Chinese patent application No. 202011250638.2 entitled "Structure of steric hindrance adjustable weak base light stabilizer and preparation method and application thereof". The present application belongs to the field of new compounds and their synthesis methods, and specifically relates to a steric hindrance adjustable weak base light stabilizer and a preparation method and application thereof. The innovative light stabilizer of the present application adjusts the steric hindrance by establishing the size of the substituent group that produces steric hindrance around the nitrogen atom in the general structure. In addition, by adjusting the distance of the polar group, the electronegativity of the nitrogen atom can be affected, thereby adjusting its basicity or nucleophilic property. By adjusting the steric hindrance and nucleophilic property or basicity of the nitrogen atom in the environment, the desired effect is obtained, and the application range of the innovative light stabilizer is widened, so that it is widely applicable to PC, polyester, PU, PVC and other acidic or electrophilic polymer materials as a light stability protection aid.

Description

[0001] This invention is a divisional application of Chinese invention patent application No. 202011250638.2, filed on November 11, 2020, entitled "Structure of Steric Hinderable Weak Base Light Stabilizer, Preparation Method and Application thereof". Technical Field

[0002] This invention patent belongs to the field of new compounds and their synthesis methods, specifically relating to sterically tunable weak base light stabilizers, their preparation methods, and applications. Background Technology

[0003] Polymer materials play an increasingly important role in today's developed world, ranging from simple, one-off industrial products to high-tech components used in space. Such diverse and complex applications require polymer materials to possess the diverse physicochemical properties necessary for specific applications. Therefore, polymer materials have become increasingly complex, not only composed of various basic polymers but also requiring the addition of a wide variety of additives, including different functional auxiliaries. These functional additives play a decisive role in endowing polymer materials with the desired specific properties. Among polymer additives, light stabilizers and antioxidant stabilizers are arguably the most important. Their antioxidant function effectively provides polymers with protection against degradation caused by heat, other environmental oxidizing factors, and ultraviolet light during processing and use. This is of particular importance to polymer materials, as the quality of polymer antioxidant stabilizers directly predicts product lifespan and avoids crucial negative impacts caused by product failure.

[0004] Light stabilizers are playing an increasingly important role in the use of polymer materials, providing polymer products with very effective protection against photodegradation.

[0005] Light stabilizers are categorized into three main types based on their protective mechanism for polymers: ultraviolet absorbers (UVA), hindered amine light stabilizers (HALS), and light quenchers. In practical applications, these three types of light stabilizers can be used individually or in mixtures, depending on the light intensity and the required level of protection. UVA absorbs and filters out harmful ultraviolet light, converting it into heat, electromagnetic waves, and harmless long-wavelength light. This helps prevent the degradation of polymer materials and also prevents discoloration and delamination in photosensitive coatings, adhesives, and sealants.

[0006] Hindered amine light stabilizers were first developed by Mitsubishi Corporation of Japan in the 1970s, with LS-744 (2,2,6,6-tetramethylpiperidin benzoate) being developed. In 1974, Ciba-Geigy of Switzerland also synthesized the same product. Light stabilizers offer more than four times the protective effect on polymer materials compared to traditional absorbent types, and exhibit good compatibility. Internationally, the annual growth rate of hindered amine light stabilizer consumption is 20%-30%, and its total consumption accounts for 44% of the total polymer stabilizer market, ranking first among all types of stabilizers. According to a third-party forecast report on the global polymer stabilizer market in 2019, the light stabilizer market reached US$790 billion in 2019 and is projected to reach US$1.41547 trillion by 2027, with an annual growth rate of approximately 7.6%. In recent decades, due to the ever-expanding demand for hindered amine light stabilizers, innovative research and development has been very active, with new small molecule and oligomeric products constantly emerging, but all of them are based on the hindered amine core structure of 2,2,6,6-tetramethylpiperidineamine.

[0007] The structure of the active functional group of the hindered amine light stabilizer is as follows:

[0008]

[0009] Among the general structural formulas of the hindered amine core active functional groups of tetramethylpiperidine amine as described above, the most widely used hindered amine light stabilizers are structure-A type light stabilizers, which have the lowest cost. Common marketed hindered amine light stabilizers include cyasorb 3853, Hostavin 3050, Hostavin TM N 20, Tinuvin 770, Hostavin 3052, Hostavin 3058, Hostavin 3055, Uvinul 4050H, Chimassorb 2020, Uvasorb HA 88, Chimassorb 944, etc.

[0010] However, these hindered amine light stabilizers with a tetramethylpiperidine core structure cannot be used in polymers such as PVC, PC, PU, ​​and polyesters. The main reason is that the nitrogen atom in the hindered amine core of tetramethylpiperidine exhibits relatively strong basicity and nucleophilic properties. During processing and use, the nucleophilic nitrogen atom easily reacts with electrophilic or acidic functional groups on the polymer, thus catalyzing and accelerating the degradation of acidic polymer materials.

[0011] Reducing the basicity or nucleophilicity of the tetramethylpiperidine HALS core is the only way to broaden the application range of hindered amine light stabilizers. To date, there are two methods to reduce the basicity of the nitrogen atom in tetramethylpiperidine hindered amine HALS: (1) Alkylation of the NH bond of piperidinium to form an NR bond, which increases the steric hindrance effect around the nitrogen atom in piperidinium, thereby reducing the basicity of piperidinium; (2) Introducing an alkoxy group into the NH bond of piperidinium to form an N-OR bond, which reduces the basicity of the nitrogen atom in piperidinium due to both the decrease in electronegativity and the increase in the steric hindrance effect around the nitrogen atom.

[0012] Hindered amine HALS light stabilizers are a type of free radical scavenger. Their mechanism of action is very complex. They mainly achieve photoprotection through the synergistic effect of the following mechanisms: (1) scavenging free radicals; (2) decomposing hydrogen peroxides; and (3) scavenging heavy metals.

[0013] Hindered amine light stabilizers with a structure-B and structure-C type parent nucleus, specifically tetramethylpiperidineamine, are called weakly basic light stabilizers. These N-OR type light stabilizer products, such as Chimassorb 119, Tinuvin 144, Tinuvin 292, Tinuvin 152, Tinuvin 371, Flamestab 116, Tinuvin 622, and Cyasorb 3529, are already on the market.

[0014] As shown above, the structures of weakly basic hindered amines are more complex than those of conventional hindered amines. In fact, both small-molecule and oligomeric weakly basic hindered amine light stabilizers require additional synthetic steps to obtain compared to conventional hindered amines. Therefore, they are more expensive, and the additional chemical synthesis places greater pressure on environmental protection. Summary of the Invention

[0015] This invention patent is the first to report an innovative structural light stabilizer with adjustable steric hindrance, controllable weak base properties of nitrogen atoms, and without containing the 2,2,6,6-tetramethylpiperidineamine structural fragment.

[0016] The general formula for an innovative, sterically tunable, weakly basic light stabilizer is as follows:

[0017]

[0018] Where X represents NH, NR3, and O;

[0019] Y is H, methyl, ethyl or other alkyl side chain;

[0020] R is a 5-22 carbon straight-chain or branched alkyl group;

[0021] R1 and R2 can be straight-chain alkyl groups, for example: -(CH2) n CH3, where n is a natural number between 1 and 20, can also be: i-Pr, i-Bu, isopentyl, isooctyl, cyclohexyl, substituted cyclohexyl, cyclopentyl, benzyl, substituted benzyl, allyl, substituted allyl, alkyl containing a double bond, or alkyl containing an aromatic substituted group. Alternatively, R1 and R2 together can also be used.

[0022] R1 and R2 can be the same or different; R can be the same as or different from both R1 and R2.

[0023] When R1 and R2 are different, R1 = Et, i-Pr, n-Pr, Bu, i-Bu, or C5-12 alkyl;

[0024] Hydroxyethyl or hydroxypropyl.

[0025] Specifically, the innovative small molecule light stabilizer structure described in this invention includes:

[0026]

[0027] The preparation method of the above-mentioned sterically tunable weak base light stabilizer is shown in the following reaction formula:

[0028]

[0029] The preparation steps include:

[0030] (1) Under nitrogen protection, add methyl acrylate or methyl methacrylate to the reaction flask, start stirring, then add 1-3 parts of organic solvent or no solvent, add 0.02-30% of catalyst 1, lower the temperature to 5-10℃, and then slowly add the second amine dropwise; after the dropwise addition is complete, raise the temperature to room temperature and stir for 6-24 hours, then continue heating to 40-80℃ and continue the reaction for 5-18 hours; monitor the reaction progress by TLC until the reaction is complete, remove excess methyl acrylate under vacuum, and use the remaining reaction intermediate without further purification for the next step of the reaction;

[0031] (2) Under nitrogen protection and stirring, add 0.1-5% catalyst 2 to the intermediate obtained in the first step at room temperature, then add HXR in batches. After the addition is completed, heat to 40-70℃ and react for 8-16 hours, then continue to heat to 85-140℃ and react for 48-96 hours. The reaction progress is monitored by TLC until the reaction is complete. Remove the catalyst, add recrystallization solvent for recrystallization, filter and dry to obtain a white powder solid product.

[0032] Furthermore, the organic solvent in step (1) includes methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF.

[0033] Furthermore, the catalyst 1 in step (1) is acetic acid, acidic alumina, silica gel, ortho-methoxyhydroquinone, 4,4-diphenol hydroxybenzene dimethyl ketone or m-nitrophenol.

[0034] Furthermore, the catalyst 2 in step (2) is sodium methoxide, sodium formate, diethyltin oxide, or aluminum isooctoxide.

[0035] Furthermore, the HXR in step (2) is n-dodecylamine, n-hexadecylamine, n-octadecylamine, n-dodecyl alcohol, or n-octadecyl alcohol.

[0036] Furthermore, the recrystallization solvent in step (2) is 0.5-20% aqueous ethanol, methanol, ethyl acetate or petroleum ether.

[0037] This invention also discloses the application of the sterically tunable weakly basic light stabilizer in providing light stability protection and antioxidant stability protection in the field of polymer materials.

[0038] The steric hindrance-tunable weak-base light stabilizer product designed and invented in this invention has superior steric hindrance-tunable functionality and its weak-base properties broaden its application range compared to widely used hindered amine (HALS) light stabilizers on the market. While both can provide varying degrees of weather resistance protection to polymer materials, from a chemical functional group perspective, hindered amines (HALS) are a class of light stabilizers that have been used for about half a century. Their structural characteristic is that each hindered amine light stabilizer molecule contains a 2,2,6,6-tetramethylpiperidineamine functional group. This hindered amine functional structure can rapidly transfer the active free radicals generated by photo-induced degradation of polymers, thus providing significant weather protection for polymer materials, while also having a certain antioxidant effect.

[0039] Hindered amine light stabilizers (HALS), which have been widely used for about half a century, have limited their application in some polymer materials, such as PVC, PC, polyesters, and PUs, due to the basic and nucleophilic nature of the tetramethylpiperidine amine structure itself. The nucleophilic or basic nitrogen atoms of tetramethylpiperidine amine react with these polymers, which have certain acidic or electrophilic properties, thereby degrading them. The reaction equation below illustrates the mechanism by which hindered amines (HALS) participate in the degradation of PVC polymers.

[0040]

[0041] To reduce the nucleophilic or basic properties of hindered amine light stabilizers, there are usually two methods to modify the nitrogen atom of hindered amines: (1) introduce methyl or alkyl groups onto the nitrogen atom of tetramethylpiperidineamine to increase the steric hindrance around the piperidineamine, thereby reducing its basicity or nucleophilic properties; (2) introduce alkoxy groups onto the nitrogen atom of tetramethylpiperidineamine, which can reduce the electronegativity of the nitrogen atom of piperidineamine and increase the steric hindrance around the nitrogen atom, thus reducing the basicity and nucleophilic properties.

[0042] Whether by introducing alkyl groups to increase steric hindrance and reduce basicity or nucleophilic attack capability, or by introducing alkoxy groups to reduce the electronegativity of nitrogen atoms while increasing steric hindrance and reducing basicity or nucleophilic attack capability, it requires 1-3 additional chemical reactions, especially involving oxidation, reduction or alkylation reactions. These chemical reactions not only add an extra burden to the environment, but also increase the additional product cost. Therefore, weakly basic hindered amine products have a significantly higher market price compared to ordinary hindered amine products.

[0043] The innovative photostable structure of this invention avoids the long-standing use of the 2,2,6,6-tetramethylpiperidinamine functional structure fragment. It adopts a completely new perspective, designing steric hindrance of the substituents around the nitrogen atom and controlling the polarity of the functional groups. By adjusting the size of the substituents around the nitrogen atom, the steric hindrance is adjustable and controllable. This allows for the creation of hindered amine compounds with reduced basicity, making them suitable for various photodegradation protection applications of polymers with certain electrophilic properties. Furthermore, the raw materials used in this invention are readily available, and the designed green synthesis process greatly simplifies the synthesis steps, reduces synthetic waste, and lowers synthesis costs. In addition, the innovative structure of this invention provides new opportunities for the selection of photostable agents for polymers.

[0044] The innovative light stabilizer of this invention adjusts the steric hindrance by creating substituents that generate steric hindrance around the nitrogen atom in the above general structural formula. Furthermore, by adjusting the proximity of polar groups, the electronegativity of the nitrogen atom can be affected, thereby adjusting its basicity or nucleophilic properties. By controlling the steric hindrance and nucleophilicity or basicity of the nitrogen atom's environment, the desired effect is achieved, thus broadening the application range of this innovative light stabilizer and making it suitable for use as a light stability protective agent in acidic or electrophilic polymers such as PC, polyester, and PVC.

[0045] Furthermore, the raw materials of the products disclosed in this invention are readily available, and a green and environmentally friendly synthesis process is adopted, resulting in minimal waste generation, thus providing optimal conditions for promotion and application.

[0046] The purpose of this invention is to design and synthesize a sterically tunable weakly basic light stabilizer, overcoming the current limitation that hindered light stabilizers (HALS) are difficult to apply as photostable protective agents to acidic or electrophilic polymers. Furthermore, the tunable polarity of the side chains of the structural substituents and other polar functional groups in the molecule increases its compatibility with polymers. In addition, this innovative light stabilizer breaks the nearly half-century monopoly of the fixed structure of 2,2,6,6-tetramethylpiperidineamine as the active functional group of the light stabilizer. Its characteristic structure is unavoidable in chemical synthesis, especially the additional chemical synthesis steps required to convert the conventional hindered amine structure into a weakly basic hindered amine light stabilizer, which makes cost and environmental impact unavoidable.

[0047] The steric hindrance-adjustable weakly basic light stabilizer of the present invention has readily available raw materials and can be synthesized into the desired product through green and environmentally friendly processes, which greatly facilitates its production and widespread application, making it a valuable light stability protective agent for all polymer materials (including PVC, PC, PU, ​​polyester, etc.).

[0048] This invention patent is the first to report an innovative structural light stabilizer with adjustable steric hindrance, controllable weak base properties of nitrogen atoms, and without containing the 2,2,6,6-tetramethylpiperidineamine structural fragment.

[0049] This invention patents innovative chemical structure products can be directly applied to polymer materials to provide effective light stability protection and antioxidant stability protection. It can play a role in maintaining the quality, color and function of polymer material products during long-term use. It can be applied to a series of products such as plastics, rubber, fibers, films, coatings, paints, inks and petroleum, and its market is very large.

[0050] The purpose of this invention is:

[0051] (1) Design and synthesize sterically tunable weak alkaline or near-neutral light stabilizers and make them applicable to all polymer materials (including PVC, PC, PU, ​​polyester, etc.) to provide a wider range of valuable light stability protection.

[0052] (2) Provides more photostable functional group structures, breaking the long-standing situation in the international market where 2,2,6,6-tetramethylpiperidineamine is the only photostable functional group.

[0053] (3) To provide the market with a simpler, more environmentally friendly method for synthesizing light stabilizers.

[0054] Compared with the prior art, the present invention solves the following problems:

[0055] (1) It solved and changed the state of 2,2,6,6-tetramethylpiperidine, a light stabilizer with fixed steric hindrance, as the only option in history.

[0056] (2) The structure of the newly designed light stabilizer is adjustable based on the required steric hindrance and the basicity and nucleophilic properties of the light stabilizer, which broadens the application range of light stabilizers in polymer materials.

[0057] (3) The designed weakly basic and weakly nucleophilic innovative structured light stabilizers provide new opportunities for polymer materials such as PVC, PC, polyester, and PU that cannot currently use light stabilizers that are inhibited by tetramethylpiperidineamine, and provide these polymer materials with better choices of UV protectants.

[0058] (4) It solves the problem of mismatch between 2,2,6,6-tetramethylpiperidineamine alkaline light stabilizers and acidic additives.

[0059] (5) Breaking through the complicated synthesis methods of weakly alkaline light stabilizers on the market, a new type of light stabilizer was synthesized using an optimized, simple, and green synthesis method.

[0060] (6) The steric hindrance adjustable weak alkaline light stabilizer of the present invention exhibits better compatibility with polymer materials, thereby improving its resistance to heat aging and yellowing and extending its service life. Attached Figure Description

[0061] Figure 1 Comparison of PP-T20 sample thermal and photoaging results (Note: (1) The top row of samples is the result of 192 hours of thermal aging in an oven at 150℃, and the bottom row of samples is the result of 157 hours of UVB ultraviolet aging at 70℃; (2) Test comparison standard samples: B1 is 3853, B2 is 770, B3 is 622; (3) B4-B13 are the innovative antioxidants and osmotic resistance adjustable light stabilizers of this invention).

[0062] Figure 2 Comparison of ABS sample results after thermal and photoaging (Note: (1) The top row of samples is the result of thermal aging in an oven at 110℃ for 178 hours, and the bottom row of samples is the result of UVB photoaging at 70℃ for 113 hours; (2) Test comparison standard samples: C1 is 3853, C2 is 770, C3 is 622; (3) C4-C12 are Ruikang innovative antioxidant and osmotic resistance adjustable light stabilizer).

[0063] Figure 3 Results of UVB aging of PC samples at 70℃ for 47 hours (antioxidant AO + light stabilizer (2:1): 0.1%; UV aging test equipment was Q-Lab).

[0064] Figure 4Results of UVB aging test on PC sample at 70℃ / 17 hours ((1) The upper row of samples is the result of 17 hours of heat aging in an oven at 150℃, and the lower row of samples is the result of 48 hours of UVB aging at 70℃; (2) Test comparison standard samples: C3 is 622, C5 is 2020; (3) C1, C2, C4 are Ruikang innovative antioxidant and osmotic resistance adjustable light stabilizer; (4) UVB aging test equipment is Q-Lab UV aging tester Suzhou Guangjun ZN-PB).

[0065] Figure 5 Results of PC samples aged under UVB light at 70℃ (Note: (1) The PC samples in the bottom row are PC samples before aging; (2) The samples in the top row are samples aged under UVB light at 70℃ for 24 hours; (3) Comparison with standard samples: UV2020 (#3) and UV119 (#1)). Detailed Implementation

[0066] Table 1: Examples of Structural Analysis of Innovative Weak Base Light Stabilizers with Adjustable Osmotic Impedance Mass Spectrometry Equipment: Thermo Finnigan LCQ Advantage Thermo Fisher Scientific; NMR Equipment: Avance III 400MHz Bruker, Switzerland

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] Table 1 lists the chemical structural formulas of organic compounds, including example structures represented by the innovative light stabilizer structures listed above in this invention. The synthesis method is a solvent-free green chemical synthesis method, and the catalyst reduces the activation energy of the reaction, so that the synthesis of the target product can be successfully completed.

[0074] Synthesis method of novel light stabilizers:

[0075]

[0076] General synthesis method:

[0077] 1. Under nitrogen protection, add methyl acrylate or methyl methacrylate (1.05-3.3 mmol) to a reaction flask, start stirring, then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 0.02-30% of catalyst 1 (catalyst 1 is: acetic acid, acidic alumina, silica gel, o-methoxyhydroquinone, 4,4-diphenol-hydroxybenzene dimethyl ketone, m-nitrophenol), lower the temperature to 5-10°C, and then slowly add the second amine (1.0-1.5 mmol). After the addition is complete, raise the temperature to room temperature and stir for 6-24 hours. If the reaction requires further heating, continue heating to 40-80°C for 5-18 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate, without further purification, is used in the next reaction step.

[0078] 2. Under nitrogen protection and stirring, add 0.1-5% catalyst 2 (catalyst 2 can be sodium methoxide, sodium formate, diethyltin oxide, aluminum isooctanol, etc.) to the intermediate obtained in the first step at room temperature. Then, add n-dodecylamine, n-hexadecylamine, n-octadecylamine, n-dodecyl alcohol, or n-octadecyl alcohol in batches (0.9-1.2 mmol). After the addition is complete, raise the temperature to 40-70℃ and react for 8-16 hours, then continue to raise the temperature to 85-140℃ and react for 48-96 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 0.5-20% aqueous ethanol, methanol, ethyl acetate, or petroleum ether for recrystallization, filter to give a white powder solid product, dry, yield 87-96%.

[0079] Product Instance Synthesis Method

[0080] The synthesis method of instance structure A:

[0081]

[0082] 1. Under nitrogen protection, add methyl acrylate (1.05-3.3 mmol) to a reaction flask and start stirring. Then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 100-1000 ppm of catalyst, ortho-methoxyhydroquinone, 4,4-diphenol-hydroxyphenyldimethyl ketone, or m-nitrophenol. Lower the temperature to 10-15°C, and then slowly add 0.9-1.5 mmol of 4-methylpiperidinamine. After the addition is complete, raise the temperature to room temperature and stir for 10-20 hours, then heat to 40-50°C and continue the reaction for 5-7 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate is used directly in the next reaction without further purification.

[0083] 2. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate to the intermediate obtained in the first step at room temperature, followed by the addition of n-octadecylamine (0.9-1.2 mmol) in portions. After the addition is complete, raise the temperature to 50-70°C and react for 12-18 hours, then continue to raise the temperature to 85-140°C and react for 48-96 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 5% aqueous ethanol or methanol for recrystallization, and a white powder solid product is given. After drying, the yield is 91.2%.

[0084] The synthesis method of instance structure B:

[0085]

[0086] 1. Under nitrogen protection, add methyl acrylate (1.3-3.5 mmol) to a reaction flask, start stirring, then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 30% silica gel (400 mesh), lower the temperature to 15-20°C, and then slowly add diisobutylamine (0.9-1.5 mmol). After the addition is complete, raise the temperature to room temperature and stir for 15-20 hours, then heat to 40-50°C and continue the reaction for 3-5 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate is used directly in the next step without further purification.

[0087] 2. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate to the intermediate obtained in the first step at room temperature, followed by the addition of n-octadecylamine (0.9-1.2 mmol) in portions. After the addition is complete, raise the temperature to 60-70°C and react for 10-13 hours, then continue to raise the temperature to 80-140°C and react for 48-96 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 0.5% aqueous petroleum ether, and recrystallize to give a white powder solid product. Dry the product; the yield is 89.3%.

[0088] mp79-81℃

[0089] The synthesis method of instance structure C:

[0090]

[0091] 1. Under nitrogen protection, add methyl acrylate (1.3-3.5 mmol) to a reaction flask and start stirring. Then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 300-700 ppm of 4,4'-diphenol hydroxybenzophenone. Lower the temperature to 10-15°C, and then slowly add dibenzylamine (0.9-1.5 mmol). After the addition is complete, raise the temperature to room temperature and stir for 18-20 hours. Then heat to 50-60°C and continue the reaction for 5-7 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate is used directly in the next step without further purification.

[0092] 2. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate, or no catalyst, to the intermediate obtained in the first step at room temperature. Then, add n-octadecylamine (0.9-1.2 mmol) in portions. After the addition is complete, raise the temperature to 50-70°C and react for 15-18 hours, then continue to raise the temperature to 85-140°C and react for 24-96 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 5% aqueous ethanol, and recrystallize to give a white powder solid product. Dry the product; the yield is 92%.

[0093] mp140-143℃.

[0094] The synthesis method of instance structure D:

[0095]

[0096] 1. Under nitrogen protection, add methyl acrylate (1.3-3.5 mmol) to a reaction flask and start stirring. Then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 200-600 ppm of 4,4'-diphenol hydroxybenzophenone or o-methoxyhydroquinone. Lower the temperature to 15-18°C, and then slowly add methylcyclohexylamine (0.95-1.2 mmol). After the addition is complete, raise the temperature to room temperature and stir for 15-20 hours, then heat to 50-60°C and continue the reaction for 2-3 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate is used directly in the next reaction without further purification.

[0097] 2. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate, or no catalyst, to the intermediate obtained in the first step at room temperature. Then, add n-octadecylamine (0.95-1.0 mmol) in portions. After the addition is complete, raise the temperature to 50-60°C and react for 5-8 hours, then continue to raise the temperature to 85-140°C and react for 24-72 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 5-10% aqueous ethanol, and recrystallize to give a white powder solid product. Dry the product; the yield is 87%.

[0098] mp67-70℃.

[0099] The synthesis method of instance structure E:

[0100]

[0101] 1. Under nitrogen protection, add methyl acrylate (1.5-3.0 mmol) to a reaction flask, start stirring, then add 1-3 parts of methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF, or no solvent. Add 100-600 ppm of 4,4'-diphenol hydroxybenzophenone or o-methoxyhydroquinone, and slowly add morpholine (0.97-1.3 mmol) dropwise at room temperature. Stir at room temperature (25°C) for 18-36 hours, then heat to 40-60°C and continue the reaction for 3-6 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining reaction intermediate is used directly in the next step without further purification.

[0102] 2. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate, or no catalyst, to the intermediate obtained in the first step at room temperature. Then, add n-octadecylamine (0.90-1.10 mmol) in portions. After the addition is complete, raise the temperature to 55-70℃ and react for 6-8 hours, then continue to raise the temperature to 80-140℃ and react for 24-72 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 5% aqueous ethanol, and recrystallize to give a white powder solid product. Dry the product; the yield is 89.3%.

[0103] The synthesis method of instance structure F:

[0104]

[0105] 1. Under nitrogen protection and stirring, add n-butylamine (1.2-1.5 mmol) to a reaction flask, followed by 1-3 parts of methanol, ethanol, dichloroethane, or acetonitrile. Then add 15-30% silica gel, acidic alumina, or 0.03-0.7% 4,4-diphenol hydroxybenzophenone or o-hydroxyhydroquinone. Add acrylonitrile (1.0 mmol) dropwise at room temperature. After the addition is complete, stir at room temperature for 2-5 hours, then raise the temperature to 30-65°C and continue the reaction for 6-15 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess n-butylamine under vacuum. The remaining oily substance is used directly in the second step without further purification.

[0106] 2. Under nitrogen protection and stirring, add 1-3 parts of methanol, ethyl acetate, or dichloroethane to the oily substance (1.0 mmol) from the previous step, then add methyl acrylate (1.5-3.0 mmol) dropwise to the reaction flask. Stir at room temperature (25°C) for 10-36 hours, then heat to 40-60°C and continue the reaction for 5-15 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove excess methyl acrylate under vacuum. The remaining oily intermediate is used directly in the next reaction step without further purification.

[0107] 3. Under nitrogen protection and stirring, add 0.1-1% sodium methoxide or sodium formate, or no catalyst, to the intermediate oily substance obtained in the second step at room temperature. Then, add n-octadecylamine (0.90-1.10 mmol) in portions. After the addition is complete, raise the temperature to 55-75℃ and react for 8-16 hours, then continue to raise the temperature to 80-140℃ and react for 24-72 hours. Monitor the reaction progress by TLC until the reaction is complete. Remove the catalyst, add 5% aqueous ethanol, and recrystallize to give a white powder solid product. Dry the product; the yield is 86.5%.

[0108] The innovative light stabilizer of this invention underwent thermal aging performance testing and UVB and 300W ultraviolet light aging performance testing in different polymer materials, as well as parallel comparative testing with commonly used light stabilizers in the international market. These tests were completed in PP, ABS, and PC polymer materials, respectively.

[0109] (1) Comparative test of the thermal aging and ultraviolet aging performance of the steric hindrance adjustable weak alkaline light stabilizer of the present invention in PP-T20

[0110] a. Twin-screw extrusion granulation

[0111] Granulation is completed by extrusion granulation using a twin-screw extruder (Nanjing Keya AK36):

[0112] Extruder parameters:

[0113] Temperatures in zones one through ten (°C): 160, 190, 210, 220, 220, 220, 210, 210, 210, 200

[0114] Speed: 300 rpm

[0115] Table 2: PP-T20 Formulation

[0116]

[0117] Main anti-B215: 0.2%; (see brand name) Figure 1 )

[0118] Light stabilizer: 0.1% (see brand name) Figure 1 )

[0119] b. Preparation of PP-T20 specimens

[0120] The PP-T20 sample was produced using a Haitian SA1200 injection molding machine.

[0121] Injection molding machine processing parameters:

[0122] Temperature ranges 1 to 5 (°C): 200, 210, 210, 205, 190;

[0123] Injection pressure: 58 bar

[0124] c. 150℃ Oven Thermal Aging Test

[0125] The oven aging was carried out in a heat aging oven in accordance with GB / T 7141-2008 Plastics Heat Aging Test Method.

[0126] d. UVB photoaging test

[0127] UVB photoaging was conducted in a UVB photoaging test chamber (Q-Lab Suzhou Guangjun) in accordance with GB / T 16422.1-2006 Plastics Laboratory Light Source Exposure Test Method Part 1 General Rules and GB / T16422.3-2014 Plastics Laboratory Light Source Exposure Test Method Part 3 Fluorescent UV Lamp Principles.

[0128] e. Results of 150℃ oven thermal aging and UVB ultraviolet light aging tests ( Figure 1 )

[0129] f. Discussion of Results

[0130] Based on the results of PP-T20 samples undergoing oven heat aging at 150℃, compared with international market products B1 (3853), B2 (770), and B3 (622) samples, the colors were significantly darker than the samples (B4-B13) containing the product of this invention. Among them, the sample (B2) with light stabilizer 770 was the darkest, the sample with 622 was lighter, and the sample (B1) with light stabilizer 3853 was the lightest among the three products from major international companies. In contrast, the samples (B4-B13) with the light stabilizer of this invention were all lighter in color than the samples with light stabilizers from the international market.

[0131] According to the VUB ultraviolet aging test results, B7 and B13 are the lightest in color. The whiteness of samples B8 and B12 is similar to that of samples 3853 (B1), 770 (B2), and 622 (B3). Samples B4, B5, and B6 are darker in color.

[0132] The steric hindrance-adjustable weakly basic light stabilizer of the present invention exhibits better compatibility with polymer materials. Therefore, it not only provides better light stability protection, but also provides better protection against heat aging and yellowing.

[0133] Mechanical performance test results:

[0134] Table 3: Comparative Test of Tensile Properties of Ruikang Innovative Light Stabilizer in PP-T20 (Comparative Samples: 3853, 770, 622) Batch Number: PPT20 RK-PT-T20201014

[0135]

[0136]

[0137]

[0138] Test conditions:

[0139] Laboratory environment: temperature 23℃, humidity 45%RH; Conditioning: 23℃, 50%RH;

[0140] Implementation standard: GB / T1040.2-2006 / ISO 527-2:1993;

[0141] Stretching speed: 50mm / min

[0142] Note: Light stabilizers ending in the letter L in the RK designation are liquid antioxidants.

[0143] Based on the comprehensive mechanical tensile data: Compared with the mechanical tensile performance test results of major international companies in Table 1, some grades of this invention exhibit outstanding performance in maintaining mechanical properties.

[0144] (a) Comparing the tensile strength before and after heat and light aging with the best market light stabilizers 3853, 770, and 622 for PP, some of the light stabilizers of this invention showed less impact on physical properties in parallel aging tests. For example, RK-AB75S, RK-AB-76S, RK-AB77, RK-ABUV721, and RK-AB71L all showed extremely good tensile strength retention after 288 hours of heat aging and 207 hours of light aging. The data showed no obvious aging effect, and the tensile strength retention rate did not change significantly. In terms of heat aging results, the retention rate was better than that of the control standard.

[0145] (b) In terms of modulus before and after aging and tensile elongation, the light stabilizer product of the present invention shows slightly better results.

[0146] (2) Comparative test of the thermal aging and ultraviolet aging performance of the steric hindrance adjustable light stabilizer of the present invention in ABS

[0147] a. Twin-screw extrusion granulation

[0148] Granulation is completed by extrusion granulation using a twin-screw extruder (Nanjing Keya AK36):

[0149] Extruder parameters:

[0150] Temperatures in zones one through ten: 200, 205, 215, 215, 215, 215, 210, 210, 205, 200

[0151] Rotational speed: 300 m / s

[0152] Main antioxidant: 0.2%; Light stabilizer: 0.1%

[0153] Standard comparison samples: C1 spline: 3808, C2 spline: 770, C3 spline: 622.

[0154] b. ABS strip preparation

[0155] The ABS sample strips were produced using Haitian SA1200 injection molding machines.

[0156] Injection molding machine processing parameters:

[0157] Temperature ranges 1 to 5: 205, 220, 220, 215, 200;

[0158] Injection pressure: 62 bar

[0159] c. 110℃ Oven Thermal Aging Test

[0160] All ABS specimens were tested in a heat aging oven at 110℃ in accordance with GB / T 7141-2008 Plastics Heat Aging Test Method.

[0161] d. UVB photoaging test

[0162] UVB photoaging was conducted in a UVB photoaging test chamber (Q-Lab Suzhou Guangjun) in accordance with GB / T 16422.1-2006 Plastics Laboratory Light Source Exposure Test Method Part 1 General Rules and GB / T16422.3-2014 Plastics Laboratory Light Source Exposure Test Method Part 3 Fluorescent UV Lamp Principles.

[0163] e. Results of ABS samples under thermal aging at 110℃ and UVB light aging tests ( Figure 2 )

[0164] f. Discussion of Results

[0165] ABS is a resin sensitive to photo-aging-induced yellowing. Based on the results of the above tests on ABS samples after 110℃ oven heat aging and UVB ultraviolet light aging, sample C7, with the addition of the innovative light stabilizer RK-AB79 and a main antioxidant of RK-701, exhibits the best anti-yellowing performance. This is followed by sample C4 (with the addition of the innovative light stabilizer RK-AB65S), and then samples C9, C8, and C5. These samples show significantly better resistance to heat aging and yellowing compared to the comparative test samples. In summary, the sterically adjustable weakly basic antioxidant of this invention still demonstrates significant performance advantages in resisting heat-induced yellowing and photo-induced yellowing in yellowing-sensitive ABS.

[0166] (3) Comparative test of the thermal aging and UVB ultraviolet aging performance of the steric hindrance adjustable light stabilizer of the present invention in PC

[0167] a. Sample preparation

[0168] PC Resin Material: PC2805 Shanghai Covestro

[0169] PC prototype preparation was completed on a Haitian SA1200 injection molding machine.

[0170] b. PC template processing parameters

[0171] PC sample preparation was completed on a Haitian SA1200 injection molding machine. Processing parameters: Temperatures (°C) for sections 1-5: 266, 273, 273, 268, 265.

[0172] Pressure: 90 bar

[0173] Speed: 44 rpm

[0174] c. PC sample aging test

[0175] (I) Results of thermal aging test in 150℃ oven

[0176] Table 4: Results of PC board heat aging at 150℃ for 4 days (96 hours) RRK-PT-PCT20201102

[0177]

[0178] (II) UVB ultraviolet aging test

[0179] Results of UVB aging of PC samples at 70℃ for 47 hours (1) Figure 3 )

[0180] The following is a list of PC boards arranged from least to most yellow after photoaging:

[0181] C2(PC-03) & C1(PC-02) <C3(622)<C5(PC-06)<C4(2020)

[0182] Results of UVB aging test on PC sample at 70℃ / 17 hours (2) Figure 4 )

[0183] Table 5: Results of UVB aging of PC boards with added light stabilizers at 70℃ for 17 hours

[0184]

[0185]

[0186] Results of UVB aging of PC samples at 70℃ (3) Figure 5 )

[0187] Table 6: Results of PC board heat aging at 150℃ for 4 days (96 hours) RRK-PT-PCT20201104

[0188]

[0189] Table 6 Data Results:

[0190] Color difference: PC-10 <PC-08<PC-07<UV119<UV2020<PC-11<PC-06<PC-09

[0191] YI:13.24(PC-08)<14.31(PC-07)<14.33(PC-10)<15.23(UV119)<15.66(PC-11)<15.87(UV2020)<17.05(PC-09)<18.14(PC-06)

[0192] d. Discussion of Results

[0193] Polycarbonate (PC) is the material most sensitive to photo-induced yellowing. In the PC samples subjected to 4 days (96 hours) of heat aging in a 150℃ oven (see Table 4-6), as described above, the color difference was between 1 and 2.6, with none exceeding 3. However, the results of the UVB light aging test after 4 days (96 hours) showed a significantly larger color difference, all between 14 and 16. Compared with international brands UV119 and UV2020, the three grades of this invention, PC-10, PC-08, and PC-07, all exhibited better resistance to photo-induced yellowing. A direct color comparison of each board before and after aging also shows that the PC samples of these three grades were lighter in color after light aging.

[0194] In summary, this innovative steric hindrance adjustable structural light stabilizer has significant advantages in adjusting structural steric hindrance, and the electronegativity environment around nitrogen atoms can also be adjusted. The production process is green and easy to operate, providing a diversified product option for reducing costs for polymer weather-resistant products.

Claims

1. A sterically tunable weakly basic light stabilizer, characterized in that, The general structural formula is as follows: ， Where X is NH; Y is H; R is a 5-22 carbon straight-chain or branched alkyl group; When R1 and R2 are the same, R1 and R2 are i-Pr, i-Bu, cyclohexyl or benzyl; R is the same as or different from R1 and R2; When R1 and R2 are different, R1 = Bu; R2 = .

2. The sterically tunable weakly basic light stabilizer according to claim 1, characterized in that, the structural formula is... include: 、 、 。 3. A method for preparing a sterically tunable weakly basic light stabilizer as described in claim 1, characterized in that, The preparation steps include: (1) Under nitrogen protection, add methyl acrylate to the reaction flask, start stirring, then add organic solvent or no solvent, add catalyst 1, lower the temperature to 5-10℃, and then slowly add the second amine; after the addition is complete, raise the temperature to room temperature and stir for 6-24 hours, then continue heating to 40-80℃ and continue the reaction for 5-18 hours; monitor the reaction progress by TLC until the reaction is complete, remove excess methyl acrylate under vacuum, and use the remaining reaction intermediate without further purification for the next step of the reaction; (2) Under nitrogen protection and stirring, catalyst 2 is added to the intermediate obtained in the first step reaction at room temperature, and then HXR is added in batches. After the addition is completed, the temperature is raised to 40-70℃ and reacted for 8-16 hours. The temperature is then raised to 85-140℃ and reacted for 48-96 hours. The reaction process is monitored by TLC until the reaction is complete. The catalyst is removed, recrystallization solvent is added for recrystallization, and the product is filtered and dried to obtain a white powder solid product.

4. The preparation method according to claim 3, characterized in that, The organic solvent in step (1) includes methanol, ethanol, ethyl acetate, dichloroethane, acetone, acetonitrile, or DMF.

5. The preparation method according to claim 3, characterized in that, Catalyst 1 in step (1) is acetic acid, formic acid, acidic alumina, p-toluenesulfonic acid, silica gel, ortho-methoxyhydroquinone, 4,4-diphenol hydroxybenzene dimethyl ketone or m-nitrophenol.

6. The preparation method according to claim 3, characterized in that, The catalyst 2 in step (2) is sodium methoxide, sodium formate, acetic acid, diethyltin oxide, or aluminum isooctoxide.

7. The preparation method according to claim 3, characterized in that, The HXR in step (2) is n-dodecylamine, n-hexadecylamine, or n-octadecylamine.

8. The preparation method according to claim 3, characterized in that, The recrystallization solvent in step (2) is 0.5-20% aqueous ethanol, methanol, ethyl acetate or petroleum ether.

9. The application of a sterically tunable weakly basic light stabilizer as described in claim 1 in providing light stability protection and antioxidant stability protection in the field of polymer materials.

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