MBS (methyl methacrylate-butadiene-styrene) resin coated with composite silane in situ and preparation method thereof

Abstract

The invention provides MBS resin coated with composite silane in situ, the MBS resin sequentially comprises a butadiene / styrene inner core, a composite silane middle layer and a methyl methacrylate / styrene shell layer from inside to outside, and the composite silane middle layer accounts for 15-30% of the total weight of the MBS resin. The preparation method comprises the following steps: mixing the silane, the methyl methacrylate, the styrene, part of the emulsifier and the water according to the ratio to prepare a pre-emulsion; adding the rest emulsifier, initiator and water into the reaction kettle, uniformly stirring and mixing, heating to 60-85 DEG C, and slowly dropwise adding butadiene and styrene at the same time to prepare a butadiene / styrene core; adding the pre-emulsion and the initiator to continue the reaction; and adding methyl methacrylate and styrene, heating to 85-95 DEG C, and adding an initiator for polymerization reaction. According to the invention, composite silane is coated in situ between the core and the shell layer of the MBS resin, so that the MBS resin has excellent weather resistance and high impact resistance, and material aging is slowed down.

Description

Technical Field

[0001] The present invention relates to the technical field of MBS resin preparation, in particular to a composite silane-coated MBS resin and a preparation method thereof. Background Art

[0002] MBS resin is a core toughening modifier for engineering plastics such as polyvinyl chloride (PVC) and PC / ABS, and is widely used in new energy vehicles, 5G communication equipment, and other fields. The design and preparation technology of the core-shell structure of MBS resin directly affect the material's impact resistance, transparency, and processing performance, and has always been a key research direction in this field. High-end MBS resin application areas require materials with good weather resistance, including heat resistance, hydrolysis resistance, aging resistance, and low-temperature impact strength. For example, 5G base station antenna covers require MBS to have a mechanical property attenuation of less than 10% in an environment of -40°C to 85°C. Therefore, how to prepare highly weather-resistant MBS resin is of great research value.

[0003] Chinese patent CN117567694A discloses an MBS resin with excellent toughness and weather resistance, and its impact strength at -40°C can reach 17.5-18.2KJ / m 2 , and its impact strength can still maintain a relatively stable state after experiencing high temperature, low temperature or continuous ultraviolet irradiation. However, its process is complicated and requires the pre-preparation of silane-modified and branched nano-titanium dioxide as an auxiliary emulsifier, and chlorinated and grafted nano-titanium dioxide as a treating agent, and the use of 60 The Co irradiation method for preparing MBS core and shell structures has strict requirements on equipment and is not easy to apply industrially. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an MBS resin in situ coated with composite silane and a preparation method thereof. The preparation process is mild and simple, and the MBS resin has high weather resistance and high impact resistance, thereby solving the above-mentioned technical problems existing in the prior art.

[0005] The present invention is achieved by adopting the following technical solutions: The first aspect of the present invention is to provide an MBS resin in situ coated with a composite silane, comprising a butadiene / styrene core, a composite silane intermediate layer, and a methyl methacrylate / styrene shell layer, wherein the composite silane intermediate layer is coated on the butadiene / styrene core, and the methyl methacrylate / styrene shell layer is coated on the composite silane intermediate layer; The butadiene / styrene core is formed by copolymerization of butadiene and styrene, the methyl methacrylate / styrene shell is formed by copolymerization of methyl methacrylate and styrene, and the raw materials of the composite silane intermediate layer include silane, methyl methacrylate and styrene; The butadiene / styrene core accounts for 30-40% of the total weight of the MBS resin, the composite silane intermediate layer accounts for 15-30% of the total weight of the MBS resin, and the methyl methacrylate / styrene shell layer accounts for 30-50% of the total weight of the MBS resin.

[0006] The butadiene / styrene core, i.e., a butadiene / styrene copolymer, has a molar ratio of butadiene repeating units to styrene repeating units of (6-8):(2-4). For example, in some embodiments, the molar ratio is 6:4, 7:3, or 8:2. The butadiene / styrene core has a particle size of 200-400 nm, preferably 250-350 nm, and more preferably 270-300 nm.

[0007] The methyl methacrylate / styrene shell layer is a methyl methacrylate / styrene copolymer, wherein the molar ratio of methyl methacrylate repeating units to styrene repeating units is (5-8):(2-5). For example, in some embodiments, the molar ratio is 8:2, 7:3, 5.5:4.5, or 5:5.

[0008] The weight percentages of the raw materials in the composite silane intermediate layer are as follows: 10-30% silane, 20-40% methyl methacrylate, and 30-50% styrene.

[0009] The silane may be any commonly used silane in the art, including but not limited to at least one of aminosilane, phenylsilane, epoxysilane, mercaptosilane, alkenylsilane, and isocyanatesilane, preferably at least one of aminosilane, epoxysilane, and alkenylsilane.

[0010] Furthermore, the aminosilane includes but is not limited to at least one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropylmethyldimethoxysilane.

[0011] Furthermore, the epoxysilane includes but is not limited to at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltriethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane, and (3-epoxypropoxypropyl)methyldiethoxysilane.

[0012] Furthermore, the alkenyl silane includes but is not limited to at least one of vinyltrimethoxysilane, vinyltriethoxysilane, and 1,3-divinyltetramethyldisiloxane.

[0013] As a preferred technical solution, the raw materials of the composite silane intermediate layer also include an ultraviolet absorber and a light stabilizer.

[0014] Furthermore, the ultraviolet absorber can be a commonly used ultraviolet absorber in the art, preferably UV-531.

[0015] Furthermore, the light stabilizer may be a light stabilizer commonly used in the art, such as a hindered amine light stabilizer, preferably HALS-622.

[0016] The second aspect of the present invention is to provide a method for preparing the above-mentioned MBS resin in situ coated with composite silane, comprising the following steps: S1, 5-10 parts by weight of silane, 0-5 parts by weight of ultraviolet absorber, 0-3 parts by weight of light stabilizer, 5-16 parts by weight of methyl methacrylate, 2-10 parts by weight of styrene, 10-35 wt% of emulsifier, and water are mixed and pre-emulsified to prepare a pre-emulsion for standby use; S2, add the remaining emulsifier, 20-45wt% of the initiator and water to the reactor, stir and mix evenly, raise the temperature to 60-85°C, and slowly dropwise add 13-27 parts by weight of butadiene and 13-20 parts by weight of styrene to prepare a butadiene / styrene core, and the reaction time is 2-5 hours; S3, adding the pre-emulsion and 10-30wt% of the initiator, and continuing the reaction for 1-2 hours; S4, add 15-40 parts by weight of methyl methacrylate and 6-25 parts by weight of styrene, mix well, raise the temperature to 85-95°C, add the remaining initiator to carry out polymerization reaction, and the reaction time is 3-5 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane; The amount of the initiator added is 1-5 wt% of the total weight of the monomers, and the amount of the emulsifier added is 0.2-0.6 wt% of the total weight of the monomers.

[0017] The inventors unexpectedly discovered that preparing a pre-emulsion of silane and shell monomers to form micelles, then coating a styrene-butadiene latex core with a composite silane layer before forming a shell, can significantly improve the weather resistance and impact resistance of MBS-filled modified PVC, PC, or PC / ABS materials. The exact mechanism is not fully understood, but it is speculated that the silane-containing micelles can be directionally anchored to the core surface through hydrophobic interactions and form an interpenetrating network with the shell, thereby improving the material's impact resistance, as well as weather resistance properties such as hydrolysis resistance, heat resistance, and low-temperature impact strength. Based on these findings, the inventors completed the present invention.

[0018] Preferably, the micelle particle size of the pre-emulsion in step S1 is 50-80 nm. Dynamic light scattering (DLS) is used to monitor the micelle particle size.

[0019] Preferably, in step S2, a laser particle size analyzer is used to monitor the particle size of the butadiene / styrene core.

[0020] Furthermore, the initiator is a persulfate initiator, including but not limited to at least one of sodium persulfate, ammonium persulfate, and potassium persulfate.

[0021] Furthermore, the emulsifier is selected from at least one of anionic emulsifiers or reactive emulsifiers, including but not limited to at least one selected from sodium alkyl sulfate, sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium alkyl diphenyl ether disulfonate, alkylphenol ether ammonium sulfate, sodium salt of alkylphenol ether sulfosuccinate, sodium p-styrene sulfonate, sodium 2-acrylamide-2,2-dimethylethanesulfonate, sodium allyl succinate alkyl ester sulfonate, sodium acrylamidoisopropylsulfonate, sodium salt of alkyl acrylic acid-2-ethanesulfonic acid, wherein the alkyl is preferably C 10 -C 16 of alkyl.

[0022] Compared with the prior art, the present invention has the following beneficial effects: Through innovative design, the present invention in situ encapsulates composite silane between the core and shell of the MBS resin, which can form an interpenetrating network structure with the shell, making the MBS resin have better weather resistance and impact resistance; the micellization treatment increases the concentration of the UV absorber in the middle layer and the shell surface, effectively blocking ultraviolet rays, and the in-situ encapsulated light stabilizer can capture free radicals generated by the degradation of the base material, inhibit chain breakage, and slow down material aging. DETAILED DESCRIPTION

[0023] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are provided for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0024] The instruments or raw materials in this invention without manufacturer's indication are all conventional commercial instruments or raw materials. The UV absorber is UV-531, the light stabilizer is HALS-622 hindered amine light stabilizer, the initiator is potassium persulfate, and the emulsifier is sodium dodecyl sulfate.

[0025] Unless otherwise specified, all test parameters used in the examples of the present invention were tested using conventional methods in the art. Specifically, aging testing was conducted in accordance with ISO 4892-2 (xenon arc aging for 2500 hours), notched impact strength was tested in accordance with ASTM D256, light transmittance was tested in accordance with ISO 13468 (integrating sphere method), and tensile strength was tested in accordance with GB / T 1040.2-2006 (test speed 50 mm / min).

[0026] Example 1

[0027] S1, 8 parts by weight of 3-aminopropyltriethoxysilane, 2 parts by weight of ultraviolet absorber, 1.5 parts by weight of light stabilizer, 12 parts by weight of methyl methacrylate, 8 parts by weight of styrene, 0.1 parts by weight of emulsifier, and 200 parts by weight of water were mixed and pre-emulsified to prepare a pre-emulsion for standby use, with a micelle particle size of 70 nm; S2, 0.4 parts by weight of emulsifier, 1.3 parts by weight of initiator and 300 parts by weight of water were added to the reactor and stirred and mixed uniformly, and the temperature was raised to 80° C., and 23 parts by weight of butadiene and 19 parts by weight of styrene were slowly added dropwise to prepare a butadiene / styrene core. The reaction time was 4 hours, and the product particle size was controlled to be 300 nm; S3, adding the pre-emulsion and 0.6 parts by weight of initiator, and continuing the reaction for 1.5 hours; S4, add 32 parts by weight of methyl methacrylate and 8.5 parts by weight of styrene, mix well, raise the temperature to 90°C, add 1.2 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 4 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane.

[0028] Example 2

[0029] S1, 10 parts by weight of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 1 part by weight of ultraviolet absorber, 1 part by weight of light stabilizer, 16 parts by weight of methyl methacrylate, 4 parts by weight of styrene, 0.12 parts by weight of emulsifier, and 220 parts by weight of water were mixed and pre-emulsified to prepare a pre-emulsion for standby use, with a micelle particle size of 65 nm; S2, add 0.35 weight parts of emulsifier, 1.2 weight parts of initiator and 280 weight parts of water to the reactor and stir and mix evenly, raise the temperature to 85 ℃, and slowly add 25 weight parts of butadiene and 15 weight parts of styrene dropwise to prepare a butadiene / styrene core, react for 3 hours, and control the product particle size at 280 nm; S3, adding the pre-emulsion and 0.4 parts by weight of initiator, and continuing the reaction for 2 hours; S4, add 40 parts by weight of methyl methacrylate and 12 parts by weight of styrene, mix well, raise the temperature to 95°C, add 1.3 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 3 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane.

[0030] Example 3

[0031] S1, 5 parts by weight of vinyltriethoxysilane, 5 parts by weight of ultraviolet absorber, 3 parts by weight of light stabilizer, 5 parts by weight of methyl methacrylate, 3 parts by weight of styrene, 0.05 parts by weight of emulsifier, and 180 parts of water are mixed and pre-emulsified to prepare a pre-emulsion for standby use, with a micelle particle size of 60 nm; S2, 0.35 parts by weight of emulsifier, 1.5 parts by weight of initiator and 280 parts by weight of water were added to the reactor and stirred to mix evenly, and the temperature was raised to 65 ° C., and 25 parts by weight of butadiene and 15 parts by weight of styrene were slowly added dropwise to prepare a butadiene / styrene core. The reaction time was 5 hours, and the product particle size was controlled at 270 nm; S3, adding the pre-emulsion and 0.8 parts by weight of initiator, and continuing the reaction for 1 hour; S4, add 15 parts by weight of methyl methacrylate and 10 parts by weight of styrene, mix well, raise the temperature to 85°C, add 1.3 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 5 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane.

[0032] Example 4

[0033] No ultraviolet absorber and light stabilizer were added, and other processes were the same as in Example 1. The specific preparation process is as follows: S1, 8 parts by weight of 3-aminopropyltriethoxysilane, 12 parts by weight of methyl methacrylate, 8 parts by weight of styrene, 0.1 parts by weight of an emulsifier, and 200 parts by weight of water were mixed and pre-emulsified to prepare a pre-emulsion for standby use, with a micelle particle size of 70 nm; S2, 0.4 parts by weight of emulsifier, 1.3 parts by weight of initiator and 300 parts by weight of water were added to the reactor and stirred and mixed uniformly, and the temperature was raised to 80° C., and 23 parts by weight of butadiene and 19 parts by weight of styrene were slowly added dropwise to prepare a butadiene / styrene core. The reaction time was 4 hours, and the product particle size was controlled to be 300 nm; S3, adding the pre-emulsion and 0.6 parts by weight of initiator, and continuing the reaction for 1.5 hours; S4, add 32 parts by weight of methyl methacrylate and 8.5 parts by weight of styrene, mix well, raise the temperature to 90°C, add 1.2 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 4 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane.

[0034] Comparative Example 1 Steps S1 and S3 were omitted, i.e., no pre-emulsion was prepared and no silane intermediate layer was formed. Other processes were the same as in Example 1. The specific preparation process is as follows: S1, add 0.4 parts by weight of emulsifier, 1.3 parts by weight of initiator and 300 parts by weight of water to the reactor and stir and mix evenly, raise the temperature to 80°C, and slowly dropwise add 23 parts by weight of butadiene and 19 parts by weight of styrene to prepare a butadiene / styrene core, react for 4 hours, and control the product particle size to 300 nm; S2, add 32 parts by weight of methyl methacrylate and 8.5 parts by weight of styrene, mix well, raise the temperature to 90°C, add 1.2 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 4 hours; S3. After the reaction is completed, the product is post-treated to obtain MBS resin.

[0035] Comparative Example 2 No pre-emulsion was prepared, and silane, UV absorber and light stabilizer were directly added in the late polymerization stage. Other processes were the same as in Example 1. The specific preparation process is as follows: S1, add 0.4 parts by weight of emulsifier, 1.3 parts by weight of initiator and 300 parts by weight of water to the reactor and stir and mix evenly, raise the temperature to 80°C, and slowly dropwise add 23 parts by weight of butadiene and 19 parts by weight of styrene to prepare a butadiene / styrene core, react for 4 hours, and control the product particle size to 300 nm; S2, add 32 parts by weight of methyl methacrylate and 8.5 parts by weight of styrene, mix well, raise the temperature to 90°C, add 1.2 parts by weight of initiator to carry out polymerization reaction, and the reaction time is 4 hours; S3, adding 8 parts by weight of 3-aminopropyltriethoxysilane, 2 parts by weight of ultraviolet absorber, and 1.5 parts by weight of light stabilizer, and continuing the reaction for 1.5 hours; S4. After the reaction is completed, the product is post-treated to obtain MBS resin.

[0036] Application Examples

[0037] The MBS resin prepared in Examples 1-4 and Comparative Examples 1-2 was added to PVC resin to prepare test samples. The specific test steps were as follows: 900 g of PVC resin, 85 g of MBS resin, 13 g of calcium stearate, and 2 g of polyethylene wax were added to a high-speed mixer and stirred and mixed uniformly. The mixture was then fed into a twin-screw extruder for extrusion molding to obtain test samples E1-E4 (corresponding to Examples 1-4) and D1-D2 (corresponding to Counterpart 1-2), respectively.

[0038] The test specimens were subjected to an aging test (xenon lamp aging for 2500 hours) in accordance with ISO 4892-2. The transmittance, tensile strength, and flexural modulus before and after aging were measured. The results are shown in Table 1. In the table, A refers to the test data before aging, and B refers to the test data after aging.

[0039] Table 1 Performance indicators of test samples before and after aging

[0040] The above test results show that the PVC samples (E1-E3) prepared using the MBS resin in situ coated with the composite silane according to the present invention exhibited tensile strength and notched impact strength degradation rates of less than 6% after aging, significantly lower than the 18-20% degradation rate observed for the PVC sample (D1) prepared using MBS resin without the composite silane. Sample D2, despite also incorporating silane, a UV absorber, and a light stabilizer into the MBS resin, also exhibited tensile strength and notched impact strength degradation rates exceeding 14% after aging, demonstrating that the in-situ coating of the composite silane between the core and shell of the MBS resin significantly improves the material's aging resistance.

[0041] The notched impact strength of PVC test samples was tested at room temperature (25°C), low temperature (referring to the test sample being kept at -40°C for 30 days) and high temperature (referring to the test sample being kept at 85°C for 30 days). The results are shown in Table 2.

[0042] Table 2 Product impact strength performance indicators

[0043] From the above test results, it can be seen that the PVC samples (E1-E4) prepared using the MBS resin in situ coated with composite silane of the present invention have a mechanical property attenuation rate of less than 10% under an environment of -40°C to 85°C, which can adapt to various harsh environments and broaden the application field.

[0044] Those skilled in the art will appreciate that the above embodiments are intended to be illustrative only and are not intended to limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and illustrated in the embodiments. Any variations or modifications may be made to the embodiments of the present invention without departing from the principles described.

Claims

1. An MBS resin in situ coated with composite silane, characterized in that: It comprises a butadiene / styrene core, a composite silane intermediate layer and a methyl methacrylate / styrene shell layer, wherein the composite silane intermediate layer is coated on the butadiene / styrene core, and the methyl methacrylate / styrene shell layer is coated on the composite silane intermediate layer; The butadiene / styrene core is formed by copolymerization of butadiene and styrene, the methyl methacrylate / styrene shell is formed by copolymerization of methyl methacrylate and styrene, and the raw materials of the composite silane intermediate layer include silane, methyl methacrylate and styrene; The butadiene / styrene core accounts for 30-40% of the total weight of the MBS resin, the composite silane intermediate layer accounts for 15-30% of the total weight of the MBS resin, and the methyl methacrylate / styrene shell layer accounts for 30-50% of the total weight of the MBS resin.

2. The MBS resin according to claim 1, wherein The molar ratio of butadiene repeating units to styrene repeating units in the butadiene / styrene core is (6-8):(2-4); the molar ratio of methyl methacrylate repeating units to styrene repeating units in the methyl methacrylate / styrene shell is (5-8):(2-5); and the weight percentages of the raw materials in the composite silane intermediate layer are as follows: 10-30% silane, 20-40% methyl methacrylate, and 30-50% styrene.

3. The MBS resin according to claim 1, wherein The silane is selected from at least one of aminosilane, epoxysilane and alkenylsilane.

4. The MBS resin according to claim 3, wherein The aminosilane is selected from at least one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropylmethyldimethoxysilane; the epoxysilane is selected from at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltriethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane, and (3-epoxypropoxypropyl)methyldiethoxysilane; the alkenylsilane is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, and 1,3-divinyltetramethyldisiloxane.

5. The MBS resin according to claim 1, wherein The raw materials of the composite silane intermediate layer also include an ultraviolet absorber and a light stabilizer.

6. The MBS resin according to claim 5, wherein The ultraviolet absorber is UV-531, and the light stabilizer is HALS-622.

7. The method for preparing the MBS resin in situ coated with composite silane according to any one of claims 1 to 6, characterized in that: The steps include: S1, 5-10 parts by weight of silane, 0-5 parts by weight of ultraviolet absorber, 0-3 parts by weight of light stabilizer, 5-16 parts by weight of methyl methacrylate, 2-10 parts by weight of styrene, 10-35 wt% of emulsifier, and water are mixed and pre-emulsified to prepare a pre-emulsion for standby use; S2, add the remaining emulsifier, 20-45wt% of the initiator and water to the reactor, stir and mix evenly, raise the temperature to 60-85°C, and slowly dropwise add 13-27 parts by weight of butadiene and 13-20 parts by weight of styrene to prepare a butadiene / styrene core, and the reaction time is 2-5 hours; S3, adding the pre-emulsion and 10-30wt% of the initiator, and continuing the reaction for 1-2 hours; S4, add 15-40 parts by weight of methyl methacrylate and 6-25 parts by weight of styrene, mix well, raise the temperature to 85-95°C, add the remaining initiator to carry out polymerization reaction, and the reaction time is 3-5 hours; S5. After the reaction is completed, the product is post-treated to obtain the MBS resin in situ coated with the composite silane; The amount of the initiator added is 1-5 wt% of the total weight of the monomers, and the amount of the emulsifier added is 0.2-0.6 wt% of the total weight of the monomers.

8. The method according to claim 7, wherein The micelle particle size of the pre-emulsion in step S1 is 50-80 nm.

9. The method according to claim 7, wherein The initiator is selected from at least one of sodium persulfate, ammonium persulfate and potassium persulfate.

10. The method according to claim 7, wherein: The emulsifier is selected from at least one of alkyl sodium sulfate, alkyl sodium sulfonate, alkyl benzene sodium sulfonate, alkyl diphenyl ether sodium disulfonate, alkylphenol ether ammonium sulfate, alkylphenol ether sulfosuccinate sodium salt, sodium p-styrene sulfonate, 2-acrylamide-2,2-dimethylethanesulfonate, allyl alkyl sulfosuccinate sodium salt, acrylamidoisopropyl sulfonate, and alkyl acrylic acid-2-ethanesulfonic acid sodium salt, wherein the alkyl is preferably C 10 -C 16 of alkyl.

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