Preparation method of MS resin

Abstract

The invention belongs to the technical field of high polymer material synthesis and preparation, and particularly relates to a preparation method of MS (Murashige and Skoog) resin, which comprises the following steps: by taking styrene and acrylate monomers as raw materials, under the combined action of an antioxidant, an initiator and a chain transfer agent, optimizing the technical process and adjusting the technical parameters, thereby obtaining the MS resin. Three-stage key process steps of internal circulation prepolymerization, polymerization in a second-stage reactor and grafting in a static mixer are set, and by accurately controlling the feeding proportion of reaction materials, catalytic materials and the like, and the reaction temperature, stirring speed, retention time, solid content proportion and the like of each process step, the high-efficiency and high-efficiency preparation of the catalyst is realized. The prepared MS resin product is pure, free of bubbles, low in product smell, good in transparency and low in haze, and has good market prospects and application and popularization values.

Description

Technical Field

[0001] The invention belongs to the field of polymer material synthesis and preparation technology, and specifically relates to a preparation method of MS resin. Background Art

[0002] Styrene-methyl methacrylate copolymer (MS) resin is a polymer obtained by copolymerization of styrene and methyl methacrylate. In addition to the good processing fluidity and low hygroscopicity of polystyrene, MS resin also has the weather resistance and excellent optical properties of methyl methacrylate. Its refractive index is 1.56, and its transparency is similar to that of polystyrene. It is a transparent, non-toxic thermoplastic. The impact strength of MS resin is higher than that of polystyrene, and its heat deformation temperature is similar to that of methyl methacrylate. MS resin has good compatibility with other polymer resins and is a good modifier.

[0003] The main uses of MS resin are food packaging containers, can linings, medical instruments, stationery, toys, shoe soles, adhesives, and for blending and modification with polystyrene, polyolefins, polyvinyl chloride and other plastics. It can also be used as transparent covers, car lampshades, electrical parts, printing parts of office machines, nameplates of household appliances, switch accessories and various other daily necessities, etc., and its application prospects are very broad.

[0004] There are three production process methods for MS: solution polymerization, bulk polymerization and suspension polymerization. Suspension polymerization has problems such as dispersants, residual impurities and wastewater pollution, and is rarely used in industrial production. Solution polymerization has the advantages of fast heat dissipation and easy control of the reaction process, and is currently a commonly used preparation method for MS resin. However, the solvent of solution polymerization needs to be processed and recycled, which makes the process long and energy consumption high. In addition, the products obtained by suspension polymerization and solution polymerization are impure, prone to yellowing, and have poor transparency. The MS production process system in the prior art has a long process flow, high energy consumption, high production cost, and can cause environmental pollution. The prepared MS resin is yellow, the product is impure, and the transparency is poor. These are technical problems that need to be solved urgently. Summary of the invention

[0005] Based on the above problems, the present invention develops a continuous bulk preparation method for MS resin. The preparation method is green and pollution-free, has a simple process flow, low energy consumption, and can effectively reduce production costs. The obtained MS resin product is pure, highly transparent, and low in haze.

[0006] A method for preparing MS resin comprises the following steps:

[0007] S1. Preparation of reaction materials: prepare a mixed solution of styrene, acrylate monomer, solvent and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer for prepolymerization, the reaction temperature is between 100-110° C., the stirring speed is 10-25 r / min, the prepolymerization residence time is 0.5-1.5 hours, and the solid content at the outlet is controlled at 12-15%;

[0008] S2, pumping the prepolymerized mixture from step S1 into a primary plug flow reactor, controlling the reaction temperature to 100-110°C, the stirring speed to 15-30r / min, the residence time to 0.5-2.0 hours, and the solid content of the material at the outlet to 45%-50%;

[0009] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 110-120°C, the stirring speed is 5-12r / min; the material residence time is 1.5-2.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0010] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 90-100°C, and the reaction temperature of the lower zone is controlled to be 120-130°C; the material residence time is 1.0-2.0 hours, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

[0011] Furthermore, the solvent is selected from toluene or ethylbenzene.

[0012] Furthermore, the initiator is not particularly limited and can be used alone or in combination. The initiator is selected from one or more of 2,2'-azobisisobutyronitrile, dilauroyl peroxide, and dibenzoyl peroxide.

[0013] Furthermore, the chain transfer agent is selected from chain transfer agents commonly used in free radical polymerization, including but not limited to at least one of n-butyl mercaptan, isobutyl mercaptan, n-dodecyl mercaptan, and tert-dodecyl mercaptan, preferably n-dodecyl mercaptan;

[0014] The antioxidant is not particularly limited and can be used alone or in combination, and is preferably 1-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0015] Furthermore, in terms of mass fraction, the amount of styrene accounts for 30-70% of the total mass of the reaction monomers, and the rest is acrylate monomers; the amount of solvent accounts for 10-20% of the total mass of the mixed solution composed of styrene, acrylate monomers, solvent and antioxidant, initiator, and chain transfer agent; the amount of initiator is 0.05-0.2% of the total mass of the reaction monomers; the amount of chain transfer agent is 0.10-0.40% of the total mass of the reaction monomers; and the amount of antioxidant is 0.1-0.3% of the total mass of the reaction monomers.

[0016] Furthermore, the acrylic acid ester monomer is selected from one of methyl methacrylate, ethyl methacrylate and butyl methacrylate, preferably methyl methacrylate.

[0017] Furthermore, the post-treatment process of step S4 is as follows: the mixed material is subjected to secondary deashing treatment to control the volatile matter content at the outlet to be less than 300 ppm.

[0018] Beneficial effects:

[0019] The invention adopts a continuous bulk polymerization method to prepare the MS resin, and the preparation process adopted is green and pollution-free, the process flow is simple, and the energy consumption is low. The MS resin product obtained by the preparation method is pure, has no bubbles, has low product odor, good transparency, and low haze. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] The preferred embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0023] Example 1

[0024] S1. Configuration of reaction materials: prepare a mixed solution of styrene, methyl methacrylate, ethylbenzene and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer in sequence for prepolymerization reaction, the reaction temperature of the internal circulation reactor is between 110° C., the stirring speed is 10 r / min, the prepolymerization residence time is 0.5 hour, and the solid content at the outlet is controlled at 12-15%;

[0025] S2, pumping the mixed material after prepolymerization in the inner circulation reactor into the primary plug flow reactor, controlling the reaction temperature to 110°C, the stirring speed to 15r / min, the residence time to 0.5 hours, and the solid content of the material at the outlet to 45%-50%;

[0026] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 120°C, the stirring speed is 5r / min; the material residence time is 1.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0027] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 100°C, and the reaction temperature of the lower zone is controlled to be 120°C; the material residence time is 1.0 hour, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

[0028] Styrene accounts for 30% of the total monomer amount, methyl methacrylate accounts for 70% of the total monomer amount, and the solvent amount accounts for 10% of the total glue amount; the initiator amount is 0.1% of the total monomer amount; the chain transfer agent amount is 0.40% of the sum of the mass of methyl methacrylate and styrene; the antioxidant amount is 0.30% of the total mass of methyl methacrylate and styrene.

[0029] The initiator is selected from 2,2'-azobisisobutyronitrile; the chain transfer agent is n-dodecyl mercaptan; and the antioxidant is 1-octadecyl-3-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0030] The prepared MS resin product is pure, has low odor, a light transmittance of 93%, and a haze of 0.5%.

[0031] Example 2

[0032] S1. Configuration of reaction materials: prepare a mixed solution of styrene, ethyl methacrylate, toluene and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer in sequence for prepolymerization reaction, the reaction temperature of the internal circulation reactor is between 100° C., the stirring speed is 25 r / min, the prepolymerization residence time is 1.5 hours, and the solid content at the outlet is controlled at 12-15%;

[0033] S2, pumping the mixed material after prepolymerization in the inner circulation reactor into the primary plug flow reactor, controlling the reaction temperature at 100°C, the stirring speed at 30r / min; the residence time at 2 hours, and the solid content of the material at the outlet at 45%-50%;

[0034] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 110°C, the stirring speed is 12r / min; the material residence time is 2.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0035] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 90°C, and the reaction temperature of the lower zone is controlled to be 130°C; the material residence time is 2.0 hours, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

[0036] Styrene accounts for 50% of the total monomer amount, methyl methacrylate accounts for 50% of the total monomer amount, and the solvent amount accounts for 20% of the total glue amount; the initiator amount is 0.2% of the total monomer amount; the chain transfer agent amount is 0.10% of the sum of the mass of methyl methacrylate and styrene; the antioxidant amount is 0.20% of the total mass of methyl methacrylate and styrene.

[0037] The initiator is selected from dibenzoyl peroxide, the chain transfer agent is selected from n-butyl mercaptan, and the antioxidant is selected from 1-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0038] The prepared MS resin product is pure, has low odor, a light transmittance of 92%, and a haze of 0.8%.

[0039] Example 3

[0040] S1. Configuration of reaction materials: prepare a mixed solution of styrene, methyl methacrylate, ethylbenzene and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer in sequence for prepolymerization reaction, the reaction temperature of the internal circulation reactor is between 110° C., the stirring speed is 10 r / min, the prepolymerization residence time is 0.5 hour, and the solid content at the outlet is controlled at 12-15%;

[0041] S2, pumping the mixed material after prepolymerization in the inner circulation reactor into the primary plug flow reactor, controlling the reaction temperature to 110°C, the stirring speed to 15r / min, the residence time to 0.5 hours, and the solid content of the material at the outlet to 45%-50%;

[0042] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 120°C, the stirring speed is 5r / min; the material residence time is 1.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0043] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 100°C, and the reaction temperature of the lower zone is controlled to be 130°C; the material residence time is 1.0 hour, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-treated and granulated to obtain MS resin.

[0044] Styrene accounts for 70% of the total monomer amount, methyl methacrylate accounts for 30% of the total monomer amount, and the solvent amount accounts for 15% of the total glue amount; the initiator amount accounts for 0.05% of the total monomer amount; the chain transfer agent amount is 0.30% of the sum of the mass of methyl methacrylate and styrene; the antioxidant amount is 0.1% of the total mass of methyl methacrylate and styrene.

[0045] The initiator is selected from dilauroyl peroxide, the chain transfer agent is selected from tert-dodecyl mercaptan, and the antioxidant is selected from 1-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0046] The prepared MS resin product is pure, has low odor, a light transmittance of 92%, and a haze of 1.5%.

[0047] Comparative Example 1

[0048] S1. Configuration of reaction materials: prepare a mixed solution of styrene, methyl methacrylate, ethylbenzene and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer in sequence for prepolymerization reaction, the reaction temperature of the internal circulation reactor is between 120°C, the stirring speed is 10r / min, the prepolymerization residence time is 0.5 hour, and the solid content at the outlet is controlled at 12-15%;

[0049] S2, pumping the mixed material after prepolymerization in the inner circulation reactor into the primary plug flow reactor, controlling the reaction temperature to 120°C, the stirring speed to 15r / min, the residence time to 0.5 hours, and the solid content of the material at the outlet to 45%-50%;

[0050] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 130°C, the stirring speed is 5r / min; the material residence time is 1.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0051] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 100°C, and the reaction temperature of the lower zone is controlled to be 140°C; the material residence time is 1.0 hour, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

[0052] Styrene accounts for 30% of the total monomer amount, methyl methacrylate accounts for 70% of the total monomer amount, and the solvent amount accounts for 20% of the total glue amount; the initiator amount is 0.2% of the total monomer amount; the chain transfer agent amount is 0.40% of the sum of the mass of methyl methacrylate and styrene; the antioxidant amount is 0.30% of the total mass of methyl methacrylate and styrene.

[0053] The initiator is selected from 2,2'-azobisisobutyronitrile; the chain transfer agent is n-dodecyl mercaptan; and the antioxidant is 1-octadecyl-3-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0054] The prepared MS resin product is pure, has low odor, a light transmittance of 85%, and a haze of 5%.

[0055] Comparative Example 2

[0056] S1. Configuration of reaction materials: prepare a mixed solution of styrene, methyl methacrylate, ethylbenzene and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer in sequence for prepolymerization reaction, the reaction temperature of the internal circulation reactor is between 120°C, the stirring speed is 10r / min, the prepolymerization residence time is 0.5 hour, and the solid content at the outlet is controlled at 12-15%;

[0057] S2, pumping the mixed material after prepolymerization in the inner circulation reactor into the primary plug flow reactor, controlling the reaction temperature to 120°C, the stirring speed to 15r / min, the residence time to 0.5 hours, and the solid content of the material at the outlet to 45%-50%;

[0058] S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 120°C, the stirring speed is 5r / min; the material residence time is 1.5 hours, and the solid content of the material at the outlet is 55%-60%;

[0059] S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 80°C, and the reaction temperature of the lower zone is controlled to be 100°C; the material residence time is 1.0 hour, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

[0060] Styrene accounts for 30% of the total monomer amount, methyl methacrylate accounts for 70% of the total monomer amount, and the solvent amount accounts for 10% of the total glue amount; the initiator amount is 0.5% of the total monomer amount; the chain transfer agent amount is 0.40% of the sum of the mass of methyl methacrylate and styrene; the antioxidant amount is 0.30% of the total mass of methyl methacrylate and styrene.

[0061] The initiator is selected from 2,2'-azobisisobutyronitrile; the chain transfer agent is n-dodecyl mercaptan; and the antioxidant is 1-octadecyl-3-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0062] The prepared MS resin product is pure, has low odor, a light transmittance of 82%, and a haze of 6%.

[0063] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent structure or equivalent process transformation made by using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A method for preparing MS resin, characterized in that: The following steps are involved: S1. Preparation of reaction materials: prepare a mixed solution of styrene, acrylate monomer, solvent and antioxidant in proportion, add initiator and chain transfer agent to the mixed solution, and stir thoroughly; place the mixed solution in a three-stage static mixer for prepolymerization, the reaction temperature is between 100-110° C., the stirring speed is 10-25 r / min, the prepolymerization residence time is 0.5-1.5 hours, and the solid content at the outlet is controlled at 12-15%; S2, pumping the prepolymerized mixture from step S1 into a primary plug flow reactor, controlling the reaction temperature to 100-110°C, the stirring speed to 15-30r / min, the residence time to 0.5-2.0 hours, and the solid content of the material at the outlet to 45%-50%; S3, the mixed material is pumped from the primary plug flow reactor to the secondary plug flow reactor, the reaction temperature is controlled at 110-120°C, the stirring speed is 5-12r / min; the material residence time is 1.5-2.5 hours, and the solid content of the material at the outlet is 55%-60%; S4, the mixed material is pumped from the secondary plug flow reactor to a static mixing reactor, the temperature of the upper and middle zones of the static mixing reactor is controlled to be 90-100°C, and the reaction temperature of the lower zone is controlled to be 120-130°C; the material residence time is 1.0-2.0 hours, and the solid content of the mixed material at the outlet is 80%-85%; after the mixed material reaches the conversion rate, it is post-processed and granulated to obtain MS resin.

2. The preparation method according to claim 1, characterized in that: In terms of mass fraction, the amount of styrene accounts for 30-70% of the total mass of the reaction monomers, and the rest is acrylate monomers; the amount of the solvent accounts for 10-20% of the total mass of the mixed solution consisting of styrene, acrylate monomers, solvent, antioxidant, initiator, and chain transfer agent; the amount of initiator is 0.05-0.2% of the total mass of the reaction monomers; the amount of chain transfer agent is 0.10-0.40% of the total mass of the reaction monomers; and the amount of antioxidant is 0.1-0.3% of the total mass of the reaction monomers.

3. The preparation method according to claim 1, characterized in that: The acrylic acid ester monomer is selected from methyl methacrylate, ethyl methacrylate and butyl methacrylate.

4. The preparation method according to claim 1, characterized in that: The initiator is selected from at least one of 2,2'-azobisisobutyronitrile, dilauroyl peroxide and dibenzoyl peroxide.

5. The preparation method according to claim 1, characterized in that: The chain transfer agent is selected from at least one of n-butyl mercaptan, isobutyl mercaptan, n-dodecyl mercaptan and tert-dodecyl mercaptan.

6. The preparation method according to claim 1, characterized in that: The antioxidant is selected from 1-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

7. The preparation method according to claim 1, characterized in that: The solvent is selected from toluene or ethylbenzene.

8. The preparation method according to claim 1, characterized in that: The post-treatment process of step S4 is as follows: the mixed material is subjected to secondary deashing treatment to control the volatile matter content at the outlet to be less than 300 ppm.