A preparation method of UV master batch for ultraviolet resistance of polycarbonate plate

Abstract

The application belongs to the technical field of polycarbonate plates, and particularly relates to a preparation method of UV master batch for polycarbonate plate anti-ultraviolet rays, which comprises the following steps: in the first step, 5-hydroxybenzotriazole and maleic anhydride are subjected to alcoholysis of anhydride to obtain an ultraviolet absorber; in the second step, the ultraviolet absorber and 3-aminopropyl triethoxysilane are subjected to amidation to obtain anti-ultraviolet silane; and in the third step, the anti-ultraviolet silane and amino-terminated poly(epsilon-caprolactone) are subjected to Michael addition to obtain the anti-ultraviolet UV master batch. The anti-ultraviolet UV master batch not only solves the traditional contradiction that mechanical properties and anti-ultraviolet properties are difficult to be considered simultaneously when polycarbonate plates are applied outdoors, but also fundamentally solves the bottleneck problems such as uneven dispersion of additives, weak interface and easy migration and precipitation in traditional physical blending.

Description

Technical Field

[0001] This invention belongs to the field of polycarbonate board technology, specifically, it relates to a method for preparing UV masterbatch for UV protection of polycarbonate boards. Background Technology

[0002] Polycarbonate (PC) is a thermoplastic engineering plastic (also known as a non-metallic additive manufacturing material) with excellent comprehensive performance. Its high transparency, excellent impact strength, heat resistance, and dimensional stability have led to its widespread application in building skylights, automotive parts, electronic appliance housings, and outdoor protective facilities. However, the ester bonds and benzene rings in the polycarbonate molecular chain are highly sensitive to ultraviolet light (especially in the 280-400 nm wavelength range). Under prolonged exposure to outdoor sunlight, it is prone to photo-oxidative aging, leading to yellowing, surface cracking, and a sharp decline in mechanical properties (especially impact toughness), severely affecting the appearance and service life of the products.

[0003] To improve the weather resistance of polycarbonate, the art typically employs the addition of small-molecule ultraviolet absorbers (such as benzotriazoles and benzophenones). These additives are dispersed in the polycarbonate matrix through physical blending, absorbing and dissipating ultraviolet light energy. However, this conventional approach has several inherent drawbacks: Dispersion and interface issues: Small molecule additives have limited compatibility with the polymer matrix and are prone to migration and aggregation during processing and long-term use, leading to uneven dispersion. This not only affects the efficiency of ultraviolet absorption but also creates defects at the phase interface, becoming stress concentration points. Often, while improving weather resistance, this damages the mechanical properties of the material, especially leading to a decrease in impact toughness.

[0004] Migration and Volatility: Small molecule additives lack a strong chemical bond with the matrix. Under the influence of heat, light, and external forces, they gradually migrate to the material surface and volatilize or precipitate. This process not only causes the UV resistance to decay rapidly over time, making it difficult to meet the needs of long-term outdoor applications, but may also contaminate the surface of the product or the materials it contacts. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing UV masterbatch for UV protection of polycarbonate boards, in order to solve the problems mentioned in the background art.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing UV masterbatch for UV protection of polycarbonate sheets includes the following steps: The first step involves reacting 5-hydroxybenzotriazole with maleic anhydride via an alcoholysis reaction to obtain an ultraviolet absorber. The second step involves reacting the ultraviolet absorber with 3-aminopropyltriethoxysilane via an amidation reaction to obtain an anti-ultraviolet silane. The third step involves reacting the UV-resistant silane with amino-terminated poly(ε-caprolactone) via a Michael addition reaction to obtain a UV-resistant masterbatch.

[0007] As a further technical solution of the present invention: the mass ratio of 5-hydroxybenzotriazole and maleic anhydride in the first step is 30-40:25-30.

[0008] As a further technical solution of the present invention: the mass ratio of the ultraviolet absorber and 3-aminopropyltriethoxysilane in the second step is 24-32:23-31.

[0009] As a further technical solution of the present invention: the mass ratio of the anti-ultraviolet silane and the amino-terminated poly(ε-caprolactone) mentioned in the third step is 19-76:20-84.

[0010] As a further technical solution of the present invention: the reaction time in the first step is 6-8 hours.

[0011] As a further technical solution of the present invention: the reaction time in the second step is 10-12 hours.

[0012] As a further technical solution of the present invention, it also includes the following steps: Polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant are mixed in a high-speed mixer according to the mass ratio; the mixed material is added to an extruder and extruded; the extruded strip is cooled to room temperature in a water tank and granulated by a pelletizer to obtain the material of UV-resistant polycarbonate sheet.

[0013] As a further technical solution of the present invention: the mass ratio of polycarbonate, UV-resistant masterbatch, toughening agent and antioxidant is 100:1-1.8:0.2-0.5:0.5-1.5.

[0014] As a further technical solution of the present invention: the antioxidant is at least one of antioxidant 1010 and antioxidant 1076, and the toughening agent is maleic anhydride modified polyethylene wax 1105A.

[0015] As a further technical solution of the present invention: the extruder is a twin-screw extruder with a length-to-diameter ratio of 40:1, and the temperatures of each temperature zone of the twin-screw extruder are as follows: Section 1: 235-245℃; Section 2: 260-275℃; Section 3: 260-275℃; Section 4: 260-275℃; Section 5: 255-265℃; Section 6: 255-265℃; Section 7: 245-260℃; Section 8: 245-260℃; Section 9: 245-260℃; Section 10: 245-260℃; Die head: 245-255℃; vacuum devourers are installed on sections 6 and 9 of the extruder.

[0016] The beneficial effects of this invention are: 1) In this invention, 5-hydroxybenzotriazole is first subjected to an alcoholysis reaction with maleic anhydride to obtain an ultraviolet absorber containing carboxyl groups and carbon-carbon double bonds. The ultraviolet absorber is then subjected to an amidation reaction with 3-aminopropyltriethoxysilane via the carboxyl groups to obtain an anti-ultraviolet silane. The anti-ultraviolet silane is then subjected to a Michael addition reaction with amino-terminated poly(ε-caprolactone) (wherein amino-terminated poly(ε-caprolactone) is a polymer with a highly reactive primary amino group at one end) via the carbon-carbon double bonds to obtain an anti-ultraviolet masterbatch. Finally, polycarbonate, the anti-ultraviolet UV masterbatch, toughening agent, and antioxidant are extruded to obtain an anti-ultraviolet polycarbonate sheet material.

[0017] 2) The amino-terminated poly(ε-caprolactone) flexible segments introduced into the UV masterbatch of the present invention have a high degree of chemical similarity and thermodynamic compatibility with the ester group structure of polycarbonate. This allows the UV masterbatch to form a strong physical entanglement and diffusion layer with the polycarbonate matrix through the principle of similar dissolves like, significantly eliminating the phase interface. In addition, the introduced polycaprolactone flexible long chain acts as an "elastomer" and can effectively initiate and terminate crazing and absorb energy when the polycarbonate is impacted.

[0018] 3) The benzotriazole structure in the UV masterbatch of this invention is a highly efficient UV absorber. Combined with the siloxane structure and amino-terminated poly(ε-caprolactone), the UV absorber is chemically grafted into the entire network in the form of covalent bonds, avoiding the performance degradation caused by migration and volatilization of small molecule UV absorbers during use. Even under high UV radiation or long-term outdoor use conditions, the board can still maintain a stable light shielding effect, effectively inhibiting the yellowing and molecular chain degradation of polycarbonate and extending the service life of the product. In summary, the UV-resistant masterbatch of this invention not only solves the traditional contradiction of balancing UV resistance and mechanical properties in outdoor applications of polycarbonate sheets, but also fundamentally addresses the bottleneck problems of uneven dispersion of additives, weak interfaces, and easy migration and precipitation in traditional physical blending. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0021] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0022] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0023] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0024] The room temperature condition is 25℃±5℃.

[0025] Example 1 A method for preparing UV masterbatch for UV protection of polycarbonate sheets includes the following steps: Step 1: Under nitrogen protection, add 40 parts of 5-hydroxybenzotriazole, 1.2 parts of dibutyltin dilaurate, and 30 parts of maleic anhydride to 250 parts of ethanol by mass. Stir well and react at room temperature for 6 hours. After the reaction is complete, remove the ethanol by rotary evaporation. Then add the residue to ethyl acetate, followed by deionized water. Separate the aqueous phase and discard it. Dry the organic phase and remove the ethyl acetate by rotary evaporation to obtain the ultraviolet absorber.

[0026] Step 2: Under nitrogen protection, add 24 parts of ultraviolet absorber and 33 parts of Caterpillar condensing agent to 250 parts of toluene by mass, react at room temperature for 45 min, then add 23 parts of 3-aminopropyltriethoxysilane, react for 12 h, add 150 parts of saturated ammonium chloride solution to the reaction solution, stir at 0℃ for 15 min, then separate the aqueous phase and keep the organic phase. Wash the organic phase with saturated brine, dry, and remove the solvent by rotary evaporation to obtain the UV-resistant silane.

[0027] Step 3: By mass, add 76 parts of amino-terminated poly(ε-caprolactone) and 0.8 parts of hexacyclic bicyclic guanidine to 800 parts of dichloromethane, then add 19 parts of UV-resistant silane. After refluxing at 55°C for 6 hours, add 200 parts of pre-cooled 1 mol / L dilute hydrochloric acid solution to the reaction solution and stir thoroughly at room temperature for 30 minutes to neutralize and quench the hexacyclic bicyclic guanidine catalyst. Transfer the mixture to a separatory funnel, let it stand and separate, discard the lower acidic aqueous phase, then add 200 parts of saturated brine to the organic phase (dichloromethane layer), separate again and discard the aqueous phase, dry the washed organic phase with anhydrous magnesium sulfate for 1 hour, and filter to remove the desiccant. The filtrate was subjected to vacuum rotary evaporation at 40°C. The concentrate was then slowly added dropwise to 1500 parts of pre-cooled anhydrous ethanol under vigorous stirring. The solid precipitated out, was filtered, and the filter cake was collected. The filter cake was washed twice with a small amount of cold ethanol and finally dried at 50°C to obtain UV-resistant masterbatch.

[0028] Step 4: Add polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant to a high-speed mixer according to the mass ratio; add the mixed material to an extruder for extrusion; cool the extruded strip to room temperature in a water tank, and granulate it through a pelletizer to obtain the material of UV-resistant polycarbonate sheet. The mass ratio of polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant is 100:1:0.2:0.5; the antioxidant is antioxidant 1010, and the toughening agent is maleic anhydride modified polyethylene wax 1105A. The extruder is a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperature zones of the twin-screw extruder are as follows: Zone 1: 235-245℃; Zone 2: 260-275℃; Zone 3: 260-275℃; Zone 4: 260-275℃; Zone 5: 255-265℃; Zone 6: 255-265℃; Zone 7: 245-260℃; Zone 8: 245-260℃; Zone 9: 245-260℃; Zone 10: 245-260℃; Die head: 245-255℃. Vacuum devourers are installed on Zones 6 and 9 of the extruder.

[0029] Example 2 A method for preparing UV masterbatch for UV protection of polycarbonate sheets includes the following steps: Step 1: Under nitrogen protection, add 30 parts of 5-hydroxybenzotriazole, 0.5 parts of dibutyltin dilaurate, and 25 parts of maleic anhydride to 350 parts of ethanol by mass. Stir well and react at room temperature for 8 hours. After the reaction is complete, remove the ethanol by rotary evaporation. Then add the residue to ethyl acetate, followed by deionized water. Separate the aqueous phase and discard it. Dry the organic phase and remove the ethyl acetate by rotary evaporation to obtain the ultraviolet absorber.

[0030] Step 2: Under nitrogen protection, add 32 parts of ultraviolet absorber and 38 parts of Caterpillar condensing agent to 330 parts of toluene by mass, react at room temperature for 30 min, then add 31 parts of 3-aminopropyltriethoxysilane, react for 10 h, add 200 parts of saturated ammonium chloride solution to the reaction solution, stir at 3℃ for 12 min, then separate the aqueous phase and keep the organic phase. Wash the organic phase with saturated brine, dry, and remove the solvent by rotary evaporation to obtain the UV-resistant silane.

[0031] Step 3: By mass, add 80 parts of amino-terminated poly(ε-caprolactone) and 0.8 parts of hexacyclic bicyclic guanidine to 800 parts of dichloromethane, then add 19.5 parts of UV-resistant silane. After refluxing at 55°C for 4 hours, add 200 parts of pre-cooled 1 mol / L dilute hydrochloric acid solution to the reaction solution and stir thoroughly at room temperature for 30 minutes to neutralize and quench the hexacyclic bicyclic guanidine catalyst. Transfer the mixture to a separatory funnel, let it stand and separate, discard the lower acidic aqueous phase, then add 200 parts of saturated brine to the organic phase (dichloromethane layer), separate again and discard the aqueous phase, dry the washed organic phase with anhydrous magnesium sulfate for 1 hour, and filter to remove the desiccant. The filtrate was subjected to vacuum rotary evaporation at 40°C. The concentrate was then slowly added dropwise to 1500 parts of pre-cooled anhydrous ethanol under vigorous stirring. The solid precipitated out, was filtered, and the filter cake was collected. The filter cake was washed twice with a small amount of cold ethanol and finally dried at 50°C to obtain UV-resistant masterbatch.

[0032] Step 4: Add polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant to a high-speed mixer according to the mass ratio; add the mixed material to an extruder for extrusion; cool the extruded strip to room temperature in a water tank, and granulate it through a pelletizer to obtain the material of UV-resistant polycarbonate sheet. The mass ratio of polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant is 100:1.4:0.3:1.0; the antioxidant is antioxidant 1076, and the toughening agent is maleic anhydride modified polyethylene wax 1105A. The extruder is a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperature zones of the twin-screw extruder are as follows: Zone 1: 235-245℃; Zone 2: 260-275℃; Zone 3: 260-275℃; Zone 4: 260-275℃; Zone 5: 255-265℃; Zone 6: 255-265℃; Zone 7: 245-260℃; Zone 8: 245-260℃; Zone 9: 245-260℃; Zone 10: 245-260℃; Die head: 245-255℃. Vacuum devourers are installed on Zones 6 and 9 of the extruder.

[0033] Example 3 A method for preparing UV masterbatch for UV protection of polycarbonate sheets includes the following steps: Step 1: Under nitrogen protection, add 33 parts of 5-hydroxybenzotriazole, 1.2 parts of dibutyltin dilaurate, and 27 parts of maleic anhydride to 320 parts of ethanol by mass. Stir well and react at room temperature for 7 hours. After the reaction is complete, remove the ethanol by rotary evaporation. Then add the residue to ethyl acetate, followed by deionized water. Separate the aqueous phase and discard it. Dry the organic phase and remove the ethyl acetate by rotary evaporation to obtain the ultraviolet absorber.

[0034] Step 2: Under nitrogen protection, add 28 parts of ultraviolet absorber and 35 parts of Caterpillar condensing agent to 280 parts of toluene by mass, react at room temperature for 35 min, then add 26 parts of 3-aminopropyltriethoxysilane, react for 11 h, add 170 parts of saturated ammonium chloride solution to the reaction solution, stir at 5 °C for 10 min, then separate the aqueous phase and keep the organic phase. Wash the organic phase with saturated brine, dry, and remove the solvent by rotary evaporation to obtain the UV-resistant silane.

[0035] Step 3: By mass, add 84 parts of amino-terminated poly(ε-caprolactone) and 0.8 parts of hexacyclic bicyclic guanidine to 800 parts of dichloromethane, then add 20 parts of UV-resistant silane. After refluxing at 55°C for 5 hours, add 200 parts of pre-cooled 1 mol / L dilute hydrochloric acid solution to the reaction solution and stir thoroughly at room temperature for 30 minutes to neutralize and quench the hexacyclic bicyclic guanidine catalyst. Transfer the mixture to a separatory funnel, let it stand and separate, discard the lower acidic aqueous phase, then add 200 parts of saturated brine to the organic phase (dichloromethane layer), separate again and discard the aqueous phase, dry the washed organic phase with anhydrous magnesium sulfate for 1 hour, and filter to remove the desiccant. The filtrate was subjected to vacuum rotary evaporation at 40°C. The concentrate was then slowly added dropwise to 1500 parts of pre-cooled anhydrous ethanol under vigorous stirring. The solid precipitated out, was filtered, and the filter cake was collected. The filter cake was washed twice with a small amount of cold ethanol and finally dried at 50°C to obtain UV-resistant masterbatch.

[0036] Step 4: Add polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant to a high-speed mixer according to the mass ratio; add the mixed material to an extruder for extrusion; cool the extruded strip to room temperature in a water tank, and granulate it through a pelletizer to obtain the material of UV-resistant polycarbonate sheet. The mass ratio of polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant is 100:1.8:0.5:1.5; the antioxidant is antioxidant 1010, and the toughening agent is maleic anhydride modified polyethylene wax 1105A. The extruder is a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperature zones of the twin-screw extruder are as follows: Zone 1: 235-245℃; Zone 2: 260-275℃; Zone 3: 260-275℃; Zone 4: 260-275℃; Zone 5: 255-265℃; Zone 6: 255-265℃; Zone 7: 245-260℃; Zone 8: 245-260℃; Zone 9: 245-260℃; Zone 10: 245-260℃; Die head: 245-255℃. Vacuum devourers are installed on Zones 6 and 9 of the extruder.

[0037] Comparative Example 1 The difference between this comparative example and Example 1 is that no UV-resistant masterbatch is added, while the other raw materials and preparation steps remain unchanged, resulting in a UV-resistant polycarbonate sheet material.

[0038] Comparative Example 2 The difference between this comparative example and Example 1 is that equal amounts of 5-hydroxybenzotriazole, 3-aminopropyltriethoxysilane, and amino-terminated polycaprolactone, which have not undergone chemical grafting, are physically mixed with polycarbonate and other additives and extruded to obtain the material of UV-resistant polycarbonate sheet.

[0039] Performance testing The material properties of the polycarbonate sheets obtained in Examples 1-3 and Comparative Examples 1-2 were tested. Standard samples were placed in a UV aging chamber and accelerated aging was performed according to ASTM G154 Cycle 1 conditions. Test conditions: UVA-340 lamp, irradiance 0.89 W / m² @ 340nm, black panel temperature 60℃, condensation temperature 50℃, cycle: 8 hours UV exposure, 4 hours condensation. Evaluation indicators: Yellowing index (ΔYI): The change in yellowing index (ΔYI) of the sample before and after aging was measured according to ASTM E313. The smaller the ΔYI value, the better the color stability. Mechanical property retention rate: The impact strength retention rate of the sample after 1000 hours of aging was tested.

[0040] The test results are as follows:

[0041] As can be seen from the table above, in this embodiment of the invention, UV-resistant masterbatch is obtained by Michael addition reaction of anti-UV silane and amino-terminated poly(ε-caprolactone) through carbon-carbon double bond; finally, polycarbonate, anti-UV masterbatch, toughening agent and antioxidant are extruded to obtain anti-UV polycarbonate sheet material, which has good UV resistance and mechanical properties.

[0042] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing UV masterbatch for UV protection of polycarbonate sheets, characterized in that, Includes the following steps: The first step involves reacting 5-hydroxybenzotriazole with maleic anhydride via an alcoholysis reaction to obtain an ultraviolet absorber. The second step involves reacting the ultraviolet absorber with 3-aminopropyltriethoxysilane via an amidation reaction to obtain an anti-ultraviolet silane. The third step involves reacting the UV-resistant silane with amino-terminated poly(ε-caprolactone) via a Michael addition reaction to obtain a UV-resistant masterbatch.

2. The method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 1, characterized in that, The mass ratio of 5-hydroxybenzotriazole and maleic anhydride mentioned in the first step is 30-40:25-30.

3. The method for preparing UV masterbatch for UV protection of polycarbonate boards according to claim 1, characterized in that, The mass ratio of the ultraviolet absorber and 3-aminopropyltriethoxysilane mentioned in the second step is 24-32:23-31.

4. The method for preparing UV masterbatch for UV protection of polycarbonate boards according to claim 1, characterized in that, The mass ratio of the UV-resistant silane and the amino-terminated poly(ε-caprolactone) mentioned in the third step is 19-76:20-84.

5. The method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 1, characterized in that, The reaction time described in the first step is 6-8 hours.

6. The method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 1, characterized in that, The reaction time described in the second step is 10-12 hours.

7. The method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 1, characterized in that, It also includes the following steps: Polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant are mixed in a high-speed mixer according to the mass ratio; the mixed material is added to an extruder and extruded; the extruded strip is cooled to room temperature in a water tank and granulated by a pelletizer to obtain UV-resistant polycarbonate sheets.

8. A method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 7, characterized in that, The mass ratio of polycarbonate, UV-resistant masterbatch, toughening agent, and antioxidant is 100:1-1.8:0.2-0.5:0.5-1.

5.

9. A method for preparing UV masterbatch for UV protection of polycarbonate sheets according to claim 7, characterized in that, The antioxidant is at least one of antioxidant 1010 and antioxidant 1076, and the toughening agent is maleic anhydride modified polyethylene wax 1105A.

10. A method for preparing a UV masterbatch for UV protection of polycarbonate sheets according to claim 7, characterized in that, The extruder is a twin-screw extruder with a length-to-diameter ratio of 40:

1. The temperature of each zone of the twin-screw extruder is as follows: Zone 1: 235-245℃; Second stage: 260-275℃; Third stage: 260-275℃; Fourth stage: 260-275℃; Fifth stage: 255-265℃; Sixth section: 255-265℃; Seventh section: 245-260℃; Eighth section: 245-260℃; Ninth section: 245-260℃; Tenth section: 245-260℃; Die head: 245-255℃; Vacuum devourers are installed on the sixth and ninth sections of the extruder.

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