A modified auxiliary agent for improving the transparency, mechanical property and anti-whiteness of PMMA and a preparation method thereof

Abstract

The application belongs to the technical field of high polymer materials, and specifically discloses a modified additive for improving the transparency, mechanical property and anti-whitening property of PMMA and a preparation method thereof. Butyl acrylate, butyl methacrylate and hydroxyethyl acrylate are used as mixed monomers to make them react as a first mixed solution (core), and then a specific reaction is carried out twice by adding mixed monomers to make the additive have excellent flexibility and impact resistance, so that stress concentration of PMMA under stress can be relieved and whitening can be reduced. Methyl methacrylate (MMA) with a refractive index close to that of PMMA is selected as a main monomer for a shell layer, and butyl methacrylate and styrene are matched, so that the modified additive and the PMMA matrix can form a good interface combination, the transparency caused by poor compatibility can be avoided, and the overall mechanical stability can be improved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a modifier for improving the transparency, mechanical properties, and anti-whitening properties of PMMA, and its preparation method. Background Technology

[0002] PMMA (polymethyl methacrylate) is widely used in optical devices, architectural decoration, and automotive parts due to its excellent transparency, weather resistance, and processing fluidity. However, existing PMMA has significant performance shortcomings: poor mechanical properties (especially impact resistance and flexibility), making it prone to brittleness; it is also prone to whitening during processing or under stress, affecting its appearance and performance; some modification schemes introduce incompatible components to improve mechanical properties, leading to decreased transparency and increased haze, making it difficult to meet multiple performance requirements. Currently, most additives used for PMMA modification are single-function, failing to achieve a synergistic improvement in transparency, mechanical properties, and resistance to whitening. Furthermore, traditional modification additive preparation processes often require high-pressure conditions, making heat removal difficult and resulting in poor product performance uniformity, thus limiting their application in high-end PMMA products. Therefore, this application is submitted. Summary of the Invention

[0003] This invention provides a modified additive for improving the transparency, mechanical properties, and anti-whitening properties of PMMA, and a method for preparing the same. The modified additive can effectively improve the transparency, mechanical properties, and anti-whitening properties of PMMA.

[0004] The present invention solves its technical problem by adopting the following technical solution: A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate evenly to obtain a mixed monomer, and set aside for later use; (2) The mixed monomers, initiator, emulsifier and water are reacted at 80~98℃ for 0.5~4h to obtain the first mixture; (3) Add the mixed monomers to the first mixture and react to obtain the second reaction solution; (4) Mix the shell reaction monomer, initiator, emulsifier and water evenly to obtain the shell reaction solution; (5) Add the shell reaction solution to the second reaction solution, react, wash with water, dry, and obtain the modified additive.

[0005] This invention uses butyl acrylate, butyl methacrylate, and hydroxyethyl acrylate as mixed monomers, and their reaction forms the first mixture (core). By adding the mixed monomers and carrying out two specific reactions, the additive is endowed with excellent flexibility and impact resistance, which can alleviate stress concentration in PMMA under stress and reduce whitening. The shell layer uses methyl methacrylate (MMA), which has a refractive index close to that of PMMA, as the main monomer, combined with butyl methacrylate and styrene, so that the modified additive and PMMA matrix form a good interface bond, avoiding the decrease in transparency due to poor compatibility, while improving the overall mechanical stability. This application, by controlling the process steps and carrying out specific core-shell reactions, can balance transparency and anti-whitening properties, form stress dispersion points under stress, inhibit crack propagation, improve impact resistance, and avoid whitening caused by excessively large particles.

[0006] As a preferred embodiment of the present invention, the mass ratio of butyl acrylate, butyl methacrylate, and hydroxyethyl acrylate is (1.5~2.5):(0.5~1.5):(6.5~7.5).

[0007] As a preferred embodiment of the present invention, the mass ratio of the mixed monomer in step (3) to the mixed monomer in step (2) is (4~6):1.

[0008] As a preferred embodiment of the present invention, the mass ratio of the mixed monomer, initiator, emulsifier and water is 1:(0.01~0.02):(0.01~0.04):(2~5).

[0009] In a preferred embodiment of the present invention, the reaction temperature in step (3) is 80~98℃ and the reaction time is 0.5~2h; The reaction temperature in step (5) is 80~98℃ and the reaction time is 1~4h.

[0010] In a preferred embodiment of the present invention, the shell reaction monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of (3~4):(2~3):(3~5).

[0011] As a preferred embodiment of the present invention, the mass ratio of the shell reaction monomer, initiator, emulsifier and water is 1:(0.01~0.02):(0.01~0.04):(2~5).

[0012] In a preferred embodiment of the present invention, the mass ratio of the shell reaction liquid to the second reaction liquid is (2.5~3.5):(6.5~7.5).

[0013] In a preferred embodiment of the present invention, the initiator includes at least one of ammonium persulfate and potassium persulfate; The emulsifier includes at least one of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether.

[0014] The present invention also provides a modified additive for improving the transparency, mechanical properties and anti-whitening properties of PMMA, which is prepared by the preparation method described above.

[0015] The beneficial effects of this invention are as follows: This invention uses butyl acrylate, butyl methacrylate, and hydroxyethyl acrylate as mixed monomers, and their reaction forms the first mixed liquid (core). By adding mixed monomers to carry out the reaction, two specific reactions are carried out, which endows the additive with excellent flexibility and impact resistance, which can alleviate stress concentration of PMMA under stress and reduce whitening. The shell layer uses methyl methacrylate (MMA), which has a refractive index close to that of PMMA, as the main monomer, combined with butyl methacrylate and styrene, so that the modified additive and PMMA matrix form a good interface bond, avoiding the decrease in transparency caused by poor compatibility, while improving the overall mechanical stability. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0018] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0019] In this invention, there are no particular limitations on the specific dispersion and stirring methods.

[0020] Unless otherwise specified, all reagents or instruments used in this invention are commercially available conventional products. Unless otherwise specified, the raw materials used in each comparative example and the parallel experiments of each embodiment are the same commercially available products.

[0021] Example 1 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0022] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0023] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0024] The mass ratio of the shell reaction solution to the second reaction solution is 2.5:7.5.

[0025] Example 2 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 1g of ammonium persulfate, 1g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0026] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.01:0.01:3.

[0027] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0028] The mass ratio of the shell reaction solution to the second reaction solution is 2.5:7.5.

[0029] Example 3 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 600g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0030] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0031] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0032] The mass ratio of the shell reaction solution to the second reaction solution is 2.5:7.5.

[0033] Example 4 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0034] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0035] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0036] The mass ratio of the shell reaction solution to the second reaction solution is 3.5:6.5.

[0037] Comparative Example 1 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h, filtered, washed with water and dried to obtain the modified additive.

[0038] Comparative Example 2 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution. Filter, wash with water, and dry to obtain the modified additive.

[0039] Comparative Example 3 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0040] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0041] (4) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0042] The mass ratio of the shell reaction solution to the second reaction solution is 2.5:7.5.

[0043] Comparative Example 4 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0044] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0045] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0046] The mass ratio of the shell reaction solution to the second reaction solution is 1:9.

[0047] Comparative Example 5 A method for preparing a modifier to improve the transparency, mechanical properties, and anti-whitening properties of PMMA includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate in a mass ratio of 2:1:7 to obtain a mixed monomer, and set aside for later use; (2) 100g of mixed monomers, 2g of ammonium persulfate, 4g of sodium dodecyl sulfate and 300g of water were reacted at 95℃ for 1.5h to obtain the first mixture; (3) Add 400g of mixed monomers to the first mixture and react at 95℃ for 1h to obtain the second reaction solution; (4) Mix the shell reaction monomer, ammonium persulfate, sodium dodecyl sulfate and water evenly to obtain the shell reaction solution; The shell-reacting monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of 3.5:2.5:4.

[0048] The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:0.02:0.04:3.

[0049] (5) Add the shell reaction solution to the second reaction solution, react at 95°C for 2 hours, filter, wash with water, and dry to obtain the modified additive.

[0050] The mass ratio of the shell reaction solution to the second reaction solution is 5:5.

[0051] Test case PMMA (CM-207, Chi Mei Chemical), modified additives, ethylene bis-stearamide, and antioxidant 1010 were mixed evenly in a mass ratio of 100:35:2:1, melt-extruded and granulated for testing.

[0052] 1. In accordance with ISO180-2019 requirements, use injection-molded A-type notched impact standard specimens to test the notched impact strength of the material.

[0053] 2. Transparency test: A 2.0mm thick high-gloss square plate (a square plate with a gloss level of not less than 90% when the light incident angle is 80°) was tested for light transmittance according to GB / T2410-2008 standard, and its resistance to stress whitening (anti-whitening) was determined according to the German Volkswagen PV3966 standard. A 500g iron ball was dropped from a height of 1m to impact the sample. The color difference ΔE of the sample before and after the ball drop was compared under a standard light source. The smaller the ΔE, the better the resistance to stress whitening.

[0054] All of the above tests were performed 10 times and the average value was taken.

[0055] Table 1

[0056] As can be seen from Table 1, the modified additives described in this application can effectively improve the transparency, mechanical properties, and anti-whitening properties of PMMA.

[0057] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a modifying agent to improve the transparency, mechanical properties, and anti-whitening properties of PMMA, characterized in that, Includes the following steps: (1) Mix butyl acrylate, butyl methacrylate and hydroxyethyl acrylate evenly to obtain a mixed monomer, and set aside for later use; (2) The mixed monomers, initiator, emulsifier and water are reacted at 80~98℃ for 0.5~4h to obtain the first mixture; (3) Add the mixed monomers to the first mixture and react to obtain the second reaction solution; (4) Mix the shell reaction monomer, initiator, emulsifier and water evenly to obtain the shell reaction solution; (5) Add the shell reaction solution to the second reaction solution, react, wash with water, dry, and obtain the modified additive.

2. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The mass ratio of butyl acrylate, butyl methacrylate, and hydroxyethyl acrylate is (1.5~2.5):(0.5~1.5):(6.5~7.5).

3. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The mass ratio of the mixed monomers in step (3) to the mixed monomers in step (2) is (4~6):

1.

4. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The mass ratio of the mixed monomer, initiator, emulsifier, and water is 1:(0.01~0.02):(0.01~0.04):(2~5).

5. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The reaction temperature in step (3) is 80~98℃, and the reaction time is 0.5~2h; The reaction temperature in step (5) is 80~98℃ and the reaction time is 1~4h.

6. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The shell reaction monomers comprise methyl methacrylate, butyl methacrylate, and styrene in a mass ratio of (3~4):(2~3):(3~5).

7. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The mass ratio of the shell reaction monomer, initiator, emulsifier, and water is 1:(0.01~0.02):(0.01~0.04):(2~5).

8. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The mass ratio of the shell reaction solution to the second reaction solution is (2.5~3.5):(6.5~7.5).

9. The method for preparing the modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA according to claim 1, characterized in that, The initiator includes at least one of ammonium persulfate and potassium persulfate; The emulsifier includes at least one of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether.

10. A modifying agent for improving the transparency, mechanical properties, and anti-whitening properties of PMMA, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 9.

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