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CN-121991291-A - Production process of solution-process grafted modified polyolefin

CN121991291ACN 121991291 ACN121991291 ACN 121991291ACN-121991291-A

Abstract

The invention discloses a process for producing solution-process grafted modified polyolefin, which comprises the steps of dissolving polyolefin raw materials in an organic solvent, adding monomers and an initiator to carry out solution-process grafting reaction, and conveying the obtained reaction solution containing a large amount of volatile matters to a screw devolatilization device for devolatilization after the reaction is finished. The screw devolatilization treatment is carried out under the conditions of decompression and heating, volatile matters are efficiently evaporated and separated from high-viscosity reaction liquid by multistage temperature control and screw structure and stroke adjustment, and a pure grafting product in a molten state is directly obtained, and the final product is obtained through granulation. The invention integrates the screw devolatilization technology into the solution grafting process, has the advantages of high grafting rate and uniform distribution, greatly reduces the energy consumption and the solvent consumption, simplifies the process flow, and realizes the continuous and large-scale production of the solution grafting modified polyolefin.

Inventors

  • XU GUOQING
  • HAN LEI
  • HE YAHONG

Assignees

  • 上海炅维新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (9)

  1. 1. The production process of the solution-process grafted modified polyolefin is characterized by comprising the following steps of: S1, carrying out grafting reaction by a solution method, namely dissolving polyolefin in an organic solvent, adding a grafting monomer and an initiator, and carrying out grafting reaction under the protection of inert atmosphere to obtain a reaction solution containing volatile matters, wherein the volatile matters comprise the organic solvent, unreacted monomers and byproducts; S2, screw devolatilization, namely directly adding the reaction liquid obtained in the step S1 into screw devolatilization equipment, and performing devolatilization under the conditions of heating and negative pressure to gasify and separate volatile matters in the reaction liquid so as to obtain grafted modified polyolefin in a molten state; And S3, granulating, namely extruding and granulating the molten grafted modified polyolefin obtained in the step S2 through a screw to obtain grafted modified polyolefin particles.
  2. 2. The process for producing a solution graft-modified polyolefin according to claim 1, wherein the devolatilization treatment is performed under reduced pressure having an absolute pressure of 0.01 to 0.03MPa in step S2.
  3. 3. The process according to claim 2, wherein in step S2, the screw devolatilization apparatus has at least two devolatilization sections connected in series, the material sequentially passes through each devolatilization section, the treatment temperature of each devolatilization section is at least 10 ℃ higher than the melting temperature of the grafted modified polyolefin, and higher than the boiling point of the volatile matter, and simultaneously lower than the degradation temperature of the grafted modified polyolefin, and the set temperature of the subsequent devolatilization section is not higher than the set temperature of the previous devolatilization section.
  4. 4. The process for producing a solution graft-modified polyolefin according to claim 3, wherein the first devolatilization stage has a set temperature in the range of +10 to-30℃of the upper limit of the melting temperature of the graft-modified polyolefin.
  5. 5. The process for producing a solution graft modified polyolefin according to claim 3 or 4, wherein the screw devolatilization apparatus has 3 to 5 devolatilization stages, and the stroke of the latter devolatilization stage is not higher than the stroke of the former devolatilization stage.
  6. 6. The process for producing solution graft modified polyolefin according to claim 5, wherein the top of each devolatilization chamber is provided with an exhaust hole and is communicated with a negative pressure exhaust pipe, a cooler is arranged at the end of the negative pressure exhaust pipe, and a collecting tank is arranged at the end of the negative pressure exhaust pipe.
  7. 7. The process for producing a solution graft-modified polyolefin according to claim 1, wherein in step S1, the polyolefin is a thermoplastic polymer material formed by polymerization or copolymerization of an olefin monomer, or a polyolefin material which has been modified.
  8. 8. The process for producing a solution graft-modified polyolefin according to claim 1, wherein in step S1, the monomer is a polymerizable unsaturated bond-containing monomer material.
  9. 9. The process for producing a solution graft-modified polyolefin according to claim 1, wherein in the step S2, the residual amount of volatile matters in the obtained graft-modified polyolefin after the devolatilization treatment with a screw is less than 100ppm.

Description

Production process of solution-process grafted modified polyolefin Technical Field The invention relates to the technical field of high polymer material modification, in particular to a production process of solution-method grafted modified polyolefin. Background Polyolefin (e.g., polyethylene, polypropylene, etc.) is widely used due to its excellent combination of properties and low cost, but its nonpolar surface properties limit its use in the fields of bonding, coating, composites, etc. The introduction of polar groups on the polyolefin molecular chain by graft modification is an effective means for improving the compatibility and adhesion thereof. At present, the polyolefin grafting modification method mainly comprises a solution grafting method, a melt grafting method, a solid phase grafting method, a radiation grafting method, a plasma grafting method and the like. The latter three methods are mainly applied to graft modification of polymer surfaces, are local modification and are less in application. The melt grafting method is carried out in an extruder or an internal mixer, has simple process and continuous production, but has the inherent defects of low grafting rate, poor grafting uniformity (micro heterogeneous), high polyolefin cracking risk, more byproducts and the like, and seriously affects the mechanical property and long-term stability of the modified product. The solution grafting method is to react in organic solvent, polyolefin molecular chain is fully stretched in solvent, monomer and initiator are distributed uniformly, so that the method has the obvious advantages of high grafting rate, uniform grafting distribution, less side reaction, capability of controlling the reaction condition accurately, etc. However, the industrial application thereof faces a huge bottleneck that the product needs to be separated and purified from a large amount of solvent after the reaction is completed. The post-treatment process of the current solution grafting method is that the reaction solution is slowly poured into high-polarity solution such as acetone, methanol or ethanol with excessive amount (usually 10-20 times of the product mass) to precipitate the modified polyolefin, the byproducts and the residual monomers are dissolved in the cleaning solution, and the complex procedures such as filtration, repeated washing, drying (or distillation) are carried out to remove the solvent, the residual monomers and the oligomeric byproducts. The process has the serious defects of (1) consuming a large amount of precipitants and cleaning agents, extremely high energy consumption for solvent recovery and high cost, (2) generating a large amount of organic waste liquid and high environmental pollution pressure, and (3) having complicated working procedures and long production period (generally requiring 24-48 h), being incapable of realizing continuous production and being limited to high-added-value products or laboratory researches. Therefore, a new process capable of retaining the grafting advantage of the solution method and overcoming the defects of post-treatment is developed, and has important significance for promoting the large-scale application of high-performance grafted polyolefin. Disclosure of Invention In order to solve the defects of complex post-treatment process, high energy consumption, heavy pollution and incapability of continuous production of solution-method grafted modified polyolefin in the prior art, the invention provides a production process of solution-method grafted modified polyolefin, which maintains the advantages of high grafting rate and uniform grafting of the existing solution-method, improves the process of subsequent product treatment, adopts screw devolatilization equipment to quickly devolatilize, improves the efficiency, simplifies the process, reduces the energy consumption and improves the productivity, and provides possibility for continuous production of the solution-method. The current technological process of grafting modified polyolefin by solution method is as follows: (1) Raw material preparation Polyolefin, organic solvent, initiator, monomer; (2) Grafting reaction Firstly, fully dissolving and swelling polyolefin in an organic solvent (the temperature is 80-150 ℃ and the solvent proportion is 50-90%); adding an initiator and a monomer, and starting the reaction under the condition of nitrogen connection and keeping a certain temperature and time (generally 80-140 ℃ for 2-10 h); (3) Product work-up Slowly adding the reacted product into excessive cleaning liquid (high-polarity liquid such as acetone/methanol/ethanol with 3-5 times of the product mass) under stirring. The grafted modified polyolefin may precipitate as a white or pale yellow solid, while the by-products and residual monomers may dissolve in the cleaning solution; Separating out the solid, and repeatedly cleaning the solid by using excessive cleaning liquid for 2-3 times (a large amount of waste