Phenolic resin with UV shielding effect and preparation process thereof

Abstract

The invention provides phenolic resin with a UV shielding effect and a preparation process thereof, and relates to the technical field of high polymer materials, by optimizing a raw material formula and the preparation process, the transmittance of the phenolic resin in an ultraviolet region with the wavelength of 280-400 nm is greatly reduced, more effective protection is provided for applications needing ultraviolet protection, and the service life of the phenolic resin is prolonged. A more stable molecular structure is formed through reasonable raw material selection and reaction condition control, the thermal stability of the phenolic resin is remarkably improved, the phenolic resin can keep stable performance in a high-temperature environment, the application range is widened, the reaction process is better controlled, growth and crosslinking of molecular chains are promoted, the weight-average molecular weight of the phenolic resin is increased, and the service life of the phenolic resin is prolonged. The ultraviolet-proof material has excellent ultraviolet shielding performance, heat stability and molecular weight, can be widely applied to the fields of coatings, plastics, adhesives and the like, and meets the requirements of different industries on high-performance ultraviolet-proof materials.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, more specifically, relates to a phenolic resin with UV shielding effect and a preparation process thereof. BACKGROUND

[0002] With the continuous development of science and technology, the performance requirements of materials in various application scenarios are increasingly improved. Among numerous materials, phenolic resin has been widely used in many fields due to its good heat resistance, corrosion resistance and mechanical properties. However, in some specific environments, such as long-term exposure to ultraviolet radiation, the performance of traditional phenolic resin often does not meet expectations.

[0003] The destructive effect of ultraviolet radiation on materials cannot be ignored, which can cause aging, discoloration and mechanical property degradation of phenolic resin, thereby shortening its service life and reducing its reliability. In order to cope with this challenge, phenolic resin with UV shielding effect has emerged as the times require.

[0004] However, the existing phenolic resin with UV shielding effect still has some technical deficiencies. On the one hand, the UV shielding performance of some existing products is not ideal, which cannot effectively block the penetration of ultraviolet rays, and it is difficult to meet the application requirements of high ultraviolet protection. On the other hand, in the preparation process, there are problems such as unreasonable selection of raw materials, inaccurate control of process parameters, etc., which lead to unstable performance of the product, and may cause certain pressure on the environment.

[0005] In addition, while improving the UV shielding performance of phenolic resin, the existing technology often sacrifices other important properties such as thermal stability and molecular weight, thereby limiting its application in a wider range.

[0006] Therefore, it is a technical problem to be solved in the current material field to develop a phenolic resin with excellent UV shielding performance, good thermal stability and high molecular weight, as well as a precisely controllable preparation process matched therewith. SUMMARY

[0007] In order to solve the above technical problems, the present application provides a phenolic resin with UV shielding effect and a preparation process thereof to solve the above problems.

[0008] A phenolic resin with UV shielding effect is made of the following raw materials by weight:

[0009] phenol 100 parts;

[0010] formaldehyde 120-150 parts, wherein the formaldehyde is added in the form of a 37%-40% mass fraction aqueous solution;

[0011] Catalyst 1-3 parts, the catalyst is a mixture of ammonium chloride and organic base, wherein ammonium chloride accounts for 60%-80% of the total weight of the catalyst;

[0012] UV absorber 5-10 parts, the UV absorber is a mixture of benzophenone and benzotriazole in a mass ratio of 1:(0.8-1.2);

[0013] Antioxidant 1-2 parts, the antioxidant is a mixture of hindered phenol and phosphite in a mass ratio of 1:(0.5-0.8);

[0014] Modified nano titanium dioxide 2-5 parts, the particle size of the modified nano titanium dioxide is 20-50 nm.

[0015] Preferably, the weight average molecular weight of the phenolic resin is 8000-12000.

[0016] Preferably, the phenolic resin has a transmittance of less than 8% in the ultraviolet region of 280-400 nm, and its UV shielding performance decreases by no more than 10% after being placed at 80°C for 100 hours.

[0017] A preparation process of a phenolic resin with UV shielding effect, comprising the following steps:

[0018] S1: phenol is added to the reaction kettle, heated to 40-50°C, and stirred uniformly at a speed of 300-500 rpm;

[0019] S2: slowly add formaldehyde to the reaction kettle, control the dropping speed, keep the temperature in the reaction kettle at 60-70°C, the dropping time is 1-1.5 hours, after dropping is completed, heat to 80-90°C, react for 1-2 hours;

[0020] S3: add catalyst, continue to react for 2-3 hours, detect the pH value of the reaction system every 30 minutes during the period, and control the pH value at 7-8 by adding acid-base regulator;

[0021] S4: cool to 50-60°C, add UV absorber and antioxidant, stir uniformly at a speed of 800-1000 rpm, and react for 0.5-1 hour;

[0022] S5: heat to 90-100°C, continue to react for 1-2 hours, and monitor the refractive index of the reaction system in real time by an online monitoring device during the reaction process, stop the reaction when the refractive index reaches a specific value C, and obtain the phenolic resin with UV shielding effect.

[0023] Preferably, the organic base is triethylamine or pyridine.

[0024] Preferably, in step S3, the acid-base regulator is a sodium hydroxide solution or a hydrochloric acid solution with a mass fraction of 10%-20%.

[0025] Preferably, in step S4, the ultraviolet absorber is added first, stirred for 15-20 minutes, and then the antioxidant is added.

[0026] Preferably, in step S5, the specific value C is calculated by the formula C=m×P, where m is a constant of 0.06, and P is the total mass of the material at the beginning of the reaction.

[0027] Preferably, the entire reaction process from step S2 to step S5 is carried out under nitrogen protection, the nitrogen flow rate is 1-2 L / min, and the pressure in the reactor is maintained at 0.1-0.2 MPa.

[0028] Preferably, after the reaction in step S5 is completed, the product is naturally cooled to room temperature and then washed with deionized water for 3-5 times. After each washing, centrifugation is performed to remove the supernatant.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Significantly improve UV shielding performance: By optimizing the raw material formula and preparation process, the transmittance of phenolic resin in the ultraviolet region of 280-400nm wavelength is greatly reduced, providing more effective protection for applications requiring UV protection.

[0031] 2. Enhanced thermal stability: Reasonable raw material selection and reaction condition control form a more stable molecular structure, significantly improving the thermal stability of phenolic resin, enabling it to maintain stable performance in higher temperature environments and expanding its application range.

[0032] 3. Increase molecular weight: Better control the reaction process, promote the growth and cross-linking of molecular chains, increase the weight-average molecular weight of phenolic resin, and thus improve its physical properties and chemical stability.

[0033] 4. Expand application areas: Its excellent UV shielding performance, thermal stability and molecular weight enable it to be widely used in coatings, plastics, adhesives and other fields, meeting the needs of different industries for high-performance UV protection materials.

[0034] 5. Optimize the raw material combination: Using a combination of multiple UV absorbers and antioxidants, and adding modified nano-titanium dioxide, not only improves product performance, but also reduces dependence on a single ingredient, thereby improving the overall performance and cost-effectiveness of the product.

[0035] 6. Precise process control: Strictly control various parameters in the preparation process, such as reaction temperature, time, pH value and stirring speed, to ensure the consistency and stability of product performance and improve product quality and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the process and components of the present invention. DETAILED DESCRIPTION

[0037] The present invention relates to a phenolic resin with UV shielding properties and a preparation process thereof. Through a specific raw material formulation and preparation steps, the phenolic resin is designed to have excellent UV shielding properties and comprehensive performance. The preparation process and its effects of the present invention are described in detail below through specific examples and comparative examples.

[0038] Experimental Materials:

[0039] Phenol: analytical grade, purity ≥99%;

[0040] Formaldehyde: aqueous solution with mass fractions of 37%, 38%, 39%, and 40%, analytical grade;

[0041] Ammonium chloride: analytical grade;

[0042] Triethylamine: analytical grade;

[0043] Pyridine: analytical grade;

[0044] Benzophenone UV absorber: analytical grade;

[0045] Benzotriazole UV absorber: analytical grade;

[0046] Hindered phenol antioxidant: analytical grade;

[0047] Phosphite antioxidant: analytical grade;

[0048] Modified nano-titanium dioxide: particle sizes are 20nm, 30nm, 40nm, and 50nm, analytically pure.

[0049] Experimental equipment:

[0050] 1. Reactor with stirring device, thermometer, reflux condenser and heating device;

[0051] 2. pH meter;

[0052] 3. Online monitoring refractive index device;

[0053] 4. Ultraviolet transmittance tester;

[0054] 5. Thermogravimetric analyzer (TGA);

[0055] 6. Centrifuge.

[0056] Example 1:

[0057] Raw material formula:

[0058] Phenol: 100g;

[0059] Formaldehyde (mass fraction 37%): 120g;

[0060] Catalyst (a mixture of ammonium chloride and triethylamine, ammonium chloride accounts for 60%): 2g;

[0061] Ultraviolet absorber (benzophenone and benzotriazole mass ratio 1:0.8): 5g;

[0062] Antioxidant (mass ratio of hindered phenols to phosphites 1:0.5): 1g;

[0063] Modified nano-titanium dioxide (particle size 20nm): 2g.

[0064] Preparation steps:

[0065] Step S1: Add 100 g of phenol into a reactor, heat to 40° C., and stir at 300 rpm;

[0066] Step S2: Slowly add 120g of formaldehyde to the reactor, controlling the addition rate to maintain the temperature at 60°C for 1 hour. After the addition is complete, raise the temperature to 80°C and react for 1 hour.

[0067] Step S3: Add 2 g of catalyst and continue the reaction for 2 hours. During this period, the pH value of the reaction system is checked every 30 minutes and the pH value is controlled at 7 by adding 10% sodium hydroxide solution.

[0068] Step S4: Cooling to 50°C, adding a UV absorber, stirring at 800 rpm for 15 minutes, then adding an antioxidant, stirring evenly, and reacting for 0.5 hours;

[0069] Step S5: Raise the temperature to 90°C and continue the reaction for 1 hour. During the reaction, the refractive index of the reaction system is monitored in real time by an online monitoring device. When the refractive index reaches a specific value (calculated by the formula C = 0.06 × P, where P is the total mass of the materials at the start of the reaction), the reaction is stopped.

[0070] Example 2:

[0071] Raw material formula:

[0072] Phenol: 100g;

[0073] Formaldehyde (mass fraction 38%): 130g;

[0074] Catalyst (mixture of ammonium chloride and pyridine, ammonium chloride accounts for 70%): 2.5g;

[0075] UV absorber (benzophenone and benzotriazole mass ratio 1:1): 7g;

[0076] Antioxidant (mass ratio of hindered phenols to phosphites 1:0.6): 1.5g;

[0077] Modified nano-titanium dioxide (particle size 30nm): 3g.

[0078] Preparation steps:

[0079] Step S1: Add 100 g of phenol into a reactor, heat to 45° C., and stir at 400 rpm;

[0080] Step S2: Slowly add 130g of formaldehyde to the reactor, controlling the addition rate to maintain the temperature in the reactor at 65°C for 1.2 hours. After the addition is complete, raise the temperature to 85°C and react for 1.5 hours.

[0081] Step S3: Add 2.5 g of catalyst and continue the reaction for 2.5 hours. During this period, the pH value of the reaction system is checked every 30 minutes and the pH value is controlled at 7.5 by adding 15% hydrochloric acid solution;

[0082] Step S4: Cooling to 55°C, adding a UV absorber, stirring at 900 rpm for 18 minutes, then adding an antioxidant, stirring evenly, and reacting for 0.8 hours;

[0083] Step S5: Raise the temperature to 95° C. and continue the reaction for 1.5 hours. During the reaction, the refractive index of the reaction system is monitored in real time by an online monitoring device. When the refractive index reaches a specific value (calculated by the formula C = 0.06 × P, where P is the total mass of the materials at the start of the reaction), the reaction is stopped.

[0084] Example 3:

[0085] Raw material formula:

[0086] Phenol: 100g;

[0087] Formaldehyde (mass fraction 39%): 140g;

[0088] Catalyst (a mixture of ammonium chloride and triethylamine, with ammonium chloride accounting for 80%): 3g;

[0089] UV absorber (benzophenone to benzotriazole mass ratio 1:1.2): 9g;

[0090] Antioxidant (mass ratio of hindered phenols to phosphites 1:0.7): 2g;

[0091] Modified nano-titanium dioxide (particle size 40nm): 4g.

[0092] Preparation steps:

[0093] Step S1: Add 100 g of phenol into a reactor, heat to 50° C., and stir at 500 rpm;

[0094] Step S2: Slowly add 140g of formaldehyde to the reactor, controlling the addition rate to maintain the temperature at 70°C for 1.5 hours. After the addition is complete, raise the temperature to 90°C and react for 2 hours.

[0095] Step S3: Add 3 g of catalyst and continue the reaction for 3 hours. During this period, the pH value of the reaction system is checked every 30 minutes and the pH value is controlled at 8 by adding 20% ​​by mass sodium hydroxide solution;

[0096] Step S4: Cooling to 60°C, adding a UV absorber, stirring at 1000 rpm for 20 minutes, then adding an antioxidant, stirring evenly, and reacting for 1 hour;

[0097] Step S5: Raise the temperature to 100° C. and continue the reaction for 2 hours. During the reaction, the refractive index of the reaction system is monitored in real time by an online monitoring device. When the refractive index reaches a specific value (calculated by the formula C = 0.06 × P, where P is the total mass of the materials at the start of the reaction), the reaction is stopped.

[0098] In order to better reflect the advantages of the present invention, the following comparative examples are provided:

[0099] Comparative Example 1:

[0100] Raw material formula:

[0101] Phenol: 100g;

[0102] Formaldehyde (mass fraction 37%): 120g;

[0103] Catalyst (ammonium chloride): 2g;

[0104] UV absorber (benzophenone): 5g;

[0105] Antioxidant (hindered phenols): 1g.

[0106] Preparation steps: The same as Example 1, except that modified nano-titanium dioxide is not added, and the types of ultraviolet absorbers and antioxidants are single.

[0107] Comparative Example 2:

[0108] Raw material formula:

[0109] Phenol: 100g;

[0110] Formaldehyde (mass fraction 38%): 130g;

[0111] Catalyst (a mixture of ammonium chloride and pyridine, with ammonium chloride accounting for 50%): 2.5 g;

[0112] UV absorber (benzotriazole): 7g;

[0113] Antioxidant (phosphite): 1.5g.

[0114] Preparation steps: Same as Example 2, except that the proportion of ammonium chloride in the catalyst is lower and the types of ultraviolet absorber and antioxidant are single.

[0115] Comparative Example 3:

[0116] Raw material formula:

[0117] Phenol: 100g;

[0118] Formaldehyde (mass fraction 39%): 140g;

[0119] Catalyst (a mixture of ammonium chloride and triethylamine, with ammonium chloride accounting for 90%): 3g;

[0120] UV absorber (benzophenone to benzotriazole mass ratio 1:0.5): 9g;

[0121] Antioxidant (mass ratio of hindered phenols to phosphites 1:0.3): 2g.

[0122] Preparation steps: Same as Example 3, except that the ratio of the ultraviolet absorber and the antioxidant is different.

[0123] UV transmittance test: Use a UV transmittance tester to measure the UV transmittance of phenolic resin in the wavelength range of 280-400nm.

[0124] Thermal stability test: A thermogravimetric analyzer (TGA) was used to measure the temperature from room temperature to 800°C at a heating rate of 10°C / min in a nitrogen atmosphere. The temperature at which the mass loss was 5% (T5%) was recorded as the thermal stability index.

[0125] Molecular weight test: The weight average molecular weight (Mw) of the phenolic resin was determined by gel permeation chromatography (GPC).

[0126] Test results:

[0127]

[0128]

[0129] Result analysis:

[0130] UV transmittance: The test results show that the transmittance of the phenolic resins prepared in Examples 1-4 in the ultraviolet region of 280-400 nm is significantly lower than that of the comparative example. This demonstrates that the present invention significantly improves the UV shielding performance of the phenolic resin by optimizing the raw material formulation and preparation process. Among them, Example 4 has the lowest UV transmittance, indicating that it has the best UV shielding effect.

[0131] Thermal stability: Examples 1-4 all exhibited superior thermal stability to the comparative example. This is due to the rational selection of raw materials and optimized reaction conditions during the preparation process of the present invention, which resulted in a more stable molecular structure and thus improved thermal stability of the phenolic resin. Example 3 exhibited the highest thermal stability, indicating that its molecular structure was the most stable.

[0132] Molecular Weight: The weight-average molecular weights of the phenolic resins prepared in Examples 1-4 were all higher than those in the comparative example. This is because the preparation process of the present invention can better control the reaction process, promoting the growth and crosslinking of the molecular chain, thereby increasing the molecular weight. Example 3 has the highest weight-average molecular weight, indicating that its molecular chain growth and crosslinking degree are the most ideal.

[0133] Comprehensively comparing the various embodiments and comparative examples, Example 4 performs well in terms of ultraviolet transmittance, thermal stability, and molecular weight, and is the optimal composition ratio and preparation process conditions of the present invention.

[0134] As can be seen from the experimental data of the above embodiments and comparative examples, resol with UV shielding effect of the present invention and preparation technology thereof have significant advantages.Through optimizing the composition of raw materials, introducing the combination of multiple ultraviolet light absorber and antioxidant, and adding modified nano titanium dioxide, strictly controlling the preparation process conditions simultaneously, as reaction temperature, time, pH value and stirring velocity etc., successfully prepared resol with excellent UV shielding performance, good thermal stability and higher molecular weight, compared with traditional resol, product of the present invention has broader application prospects in the field of ultraviolet protection, can be used for making high-performance ultraviolet protection material, as coating, plastics, adhesive etc., can effectively protect the object that is coated or encapsulated from the infringement of ultraviolet light, prolong its service life.

[0135] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A phenolic resin with UV shielding effect, characterized in that: Made from the following raw materials in parts by weight: 100 parts of phenol; 120-150 parts of formaldehyde, wherein the formaldehyde is added in the form of a 37%-40% by mass aqueous solution; 1-3 parts of a catalyst, wherein the catalyst is a mixture of ammonium chloride and an organic base, wherein the ammonium chloride accounts for 60%-80% of the total weight of the catalyst; 5-10 parts of an ultraviolet absorber, wherein the ultraviolet absorber is a mixture of benzophenone and benzotriazole in a mass ratio of 1:(0.8-1.2); 1-2 parts of antioxidant, wherein the antioxidant is a mixture of hindered phenols and phosphites in a mass ratio of 1:(0.5-0.8); 2-5 parts of modified nano titanium dioxide, wherein the particle size of the modified nano titanium dioxide is 20-50 nm.

2. A process for preparing a phenolic resin having UV shielding effect as claimed in claim 1, characterized in that: The following steps are involved: S1: Add phenol to the reactor, heat to 40-50°C, and stir at 300-500 rpm; S2: slowly add formaldehyde dropwise to the reactor, controlling the addition speed to keep the temperature in the reactor at 60-70°C for 1-1.5 hours. After the addition is complete, raise the temperature to 80-90°C and react for 1-2 hours; S3: Add the catalyst and continue the reaction for 2-3 hours. During this period, the pH value of the reaction system is checked every 30 minutes and the pH value is controlled at 7-8 by adding an acid-base regulator. S4: Cool to 50-60°C, add UV absorber and antioxidant, stir evenly at 800-1000 rpm, and react for 0.5-1 hour; S5: heating to 90-100° C. and continuing the reaction for 1-2 hours. During the reaction, the refractive index of the reaction system is monitored in real time by an online monitoring device. When the refractive index reaches a specific value C, the reaction is stopped to obtain the phenolic resin with UV shielding effect.

3. The preparation process according to claim 2, characterized in that The organic base is triethylamine or pyridine.

4. The preparation process according to claim 2, characterized in that In step S3, the acid-base regulator is a sodium hydroxide solution or a hydrochloric acid solution with a mass fraction of 10%-20%.

5. The preparation process according to claim 2, characterized in that: In step S4, the ultraviolet absorber is first added, stirred for 15-20 minutes, and then the antioxidant is added.

6. The preparation process according to claim 2, characterized in that: In step S5, the specific value C is calculated by the formula C=m×P, where m is a constant of 0.06, and P is the total mass of the material at the beginning of the reaction.

7. The phenolic resin having UV shielding effect according to claim 1, characterized in that The weight average molecular weight of the phenolic resin is 8000-12000.

8. The preparation process according to claim 2, characterized in that: The entire reaction process from step S2 to step S5 is carried out under nitrogen protection, the nitrogen flow rate is 1-2 L / min, and the pressure in the reactor is maintained at 0.1-0.2 MPa.

9. The preparation process according to claim 2, characterized in that: After the reaction in step S5 is completed, the product is naturally cooled to room temperature, and then washed with deionized water for 3-5 times. After each washing, centrifugation is performed to remove the supernatant.

10. The phenolic resin having UV shielding effect according to claim 1, characterized in that: The transmittance of the phenolic resin in the ultraviolet region with a wavelength of 280-400 nm is lower than 8%, and after being placed in an environment of 80° C. for 100 hours, the UV shielding performance thereof decreases by no more than 10%.

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