CN-121975055-A - Method for producing methacrylic resin, resin beads, resin composition, and resin film

Abstract

The invention provides a method for producing a methacrylic resin, a resin bead, a resin composition and a resin film, wherein the method comprises a polymerization step of suspension-polymerizing a monomer component having a methyl methacrylate content of 95 mass% or more in the presence of a polymerization initiator and a chain transfer agent, the polymerization initiator comprises a first polymerization initiator (azo polymerization initiator) having a 10-hour half-life temperature of 72 ℃ or less and a second polymerization initiator having a 10-hour half-life temperature of 80 ℃ or more, and the amount of the polymerization initiator is 0.02 to 0.12 mass parts relative to 100 mass parts of the monomer component. Further, provided are resin beads made of a methacrylic resin which can be produced by the production method, a resin composition containing a methacrylic resin which can be produced by the production method, a resin film containing the resin composition, and a polarizing plate and a display device using the resin film.

Inventors

• Wild Nomura
• FURUTA TAKESHI
• FURUKAWA YOSHIO
• See much of Benedict
• Gui Lanzi

Assignees

• 株式会社钟化

Dates

Publication Date

20260505

Application Date

20251028

Priority Date

20241031

Claims (19)

1. 1. A method for producing a methacrylic resin, comprising a polymerization step of suspension-polymerizing a monomer component having a methyl methacrylate content of 95 mass% or more in the presence of a polymerization initiator and a chain transfer agent, The polymerization initiator comprises a first polymerization initiator having a 10-hour half-life temperature of 72 ℃ or less and a second polymerization initiator having a 10-hour half-life temperature of 80 ℃ or more, The first polymerization initiator is an azo polymerization initiator, The amount of the polymerization initiator is 0.02 to 0.12 parts by mass based on 100 parts by mass of the monomer component.
2. 2. The method for producing a methacrylic resin according to claim 1, wherein a ratio of an amount of the second polymerization initiator to an amount of the first polymerization initiator is 0.01 to 1.0 on a mass basis.
3. 3. The method for producing a methacrylic resin according to claim 1, wherein the second polymerization initiator is a peroxide polymerization initiator or an azo polymerization initiator.
4. 4. The method for producing a methacrylic resin according to claim 1, wherein a difference between an average value of internal temperatures from 100 minutes after start of polymerization and a maximum value of internal temperatures from 100 minutes after start of polymerization to 360 minutes after start of polymerization in the polymerization step is 5.0 ℃ or less.
5. 5. A resin bead comprising a methacrylic resin having a proportion of structural units derived from methyl methacrylate of 95 mass% or more, a syndiotacticity expressed by a triad of 55% or more, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin beads is 119.0 ℃ or higher.
6. 6. The resin beads according to claim 5, wherein the weight average molecular weight (Mw) measured by Gel Permeation Chromatography (GPC) is 8 to 20 tens of thousands.
7. 7. The resin beads according to claim 5, wherein the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) as measured by Gel Permeation Chromatography (GPC) is 1.6 to 2.5.
8. 8. The resin beads according to claim 5, wherein the content of the residual chain transfer agent is 100 mass ppm or less.
9. 9. A resin composition comprising a methacrylic resin having a proportion of structural units derived from methyl methacrylate of 95 mass% or more, a syndiotacticity expressed by a triad of 55% or more, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin composition is 119.5 ℃ or higher.
10. 10. The resin composition according to claim 9, wherein the content of the residual chain transfer agent is 100 mass ppm or less.
11. 11. A resin film comprising the resin composition according to claim 9 or 10.
12. 12. The resin film according to claim 11, wherein the resin film is an optical film.
13. 13. The resin film according to claim 11, wherein the resin film is a polarizer protective film.
14. 14. A display device comprising a polarizing plate formed by laminating a polarizing plate and the resin film according to claim 13.
15. 15. A resin composition comprising a methacrylic resin having a ratio of structural units derived from methyl methacrylate of 95 mass% or more, a main chain having substantially no ring structure, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin composition is 119.5 ℃ or higher.
16. 16. The resin composition according to claim 15, wherein the content of the residual chain transfer agent is 100 mass ppm or less.
17. 17. A resin film comprising the resin composition of claim 15 or 16.
18. 18. A resin pellet comprising a methacrylic resin having a proportion of structural units derived from methyl methacrylate of 95 mass% or more, a syndiotacticity expressed by a triad of 55% or more, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin pellet is 119.5 ℃ or higher.
19. 19. A resin pellet comprising a methacrylic resin having a ratio of structural units derived from methyl methacrylate of 95 mass% or more, a main chain having substantially no ring structure, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin pellet is 119.5 ℃ or higher.

Description

Method for producing methacrylic resin, resin beads, resin composition, and resin film Technical Field The present invention relates to a method for producing a methacrylic resin, a resin bead, a resin composition, and a resin film. Background Methacrylic resins have excellent transparency, weather resistance, processability, and the like, and are therefore widely used in various fields. In particular, a resin film obtained by molding a methacrylic resin is also used for optical applications such as display devices due to its excellent optical properties. The methacrylic resin is produced, for example, by polymerizing a monomer component containing methyl methacrylate as a main component in the presence of a polymerization initiator and a chain transfer agent (for example, refer to patent document 1). Prior art literature Patent literature Patent document 1 International publication No. 2019/088025 Disclosure of Invention Problems to be solved by the invention In general, when unpolymerized monomers remain in the methacrylic resin, it is required to reduce the amount of the remaining monomers in order to improve the quality of the methacrylic resin. In this regard, by increasing the amount of the polymerization initiator, the amount of the residual monomer can be reduced. However, if the amount of the polymerization initiator is increased, there is a problem that the heat resistance and the like of the methacrylic resin are lowered by the remaining polymerization initiator. Further, if the amount of the polymerization initiator is increased, there is a problem that the amount of heat released during polymerization becomes large and temperature control becomes difficult. Accordingly, an object of the present invention is to provide a method for producing a methacrylic resin, which can produce a methacrylic resin having a small amount of residual monomers and excellent heat resistance while suppressing the amount of heat released during polymerization, a resin bead formed from the methacrylic resin produced by the production method, a resin composition containing the methacrylic resin produced by the production method, a resin film containing the resin composition, and a polarizing plate and a display device using the resin film. Solution for solving the problem Specific embodiments for solving the above problems include the following embodiments. <1> A method for producing a methacrylic resin, comprising a polymerization step of suspension-polymerizing a monomer component having a methyl methacrylate content of 95 mass% or more in the presence of a polymerization initiator and a chain transfer agent, The polymerization initiator comprises a first polymerization initiator having a 10-hour half-life temperature of 72 ℃ or less and a second polymerization initiator having a 10-hour half-life temperature of 80 ℃ or more, The first polymerization initiator is an azo polymerization initiator, The amount of the polymerization initiator is 0.02 to 0.12 parts by mass based on 100 parts by mass of the monomer component. <2> The method for producing a methacrylic resin according to <1>, wherein the ratio of the amount of the second polymerization initiator to the amount of the first polymerization initiator is 0.01 to 1.0 on a mass basis. <3> The method for producing a methacrylic resin according to <1> or <2>, wherein the second polymerization initiator is a peroxide polymerization initiator or an azo polymerization initiator. <4> The method according to any one of <1> to <3>, wherein a difference between an average value of internal temperatures from 100 minutes after start of polymerization and a maximum value of internal temperatures from 100 minutes to 360 minutes after start of polymerization in the polymerization step is 5.0 ℃ or less. <5> A resin bead comprising a methacrylic resin having a proportion of structural units derived from methyl methacrylate of 95 mass% or more, a syndiotacticity expressed by a triad of 55% or more, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass ppm or less, The glass transition temperature of the resin beads is 119.0 ℃ or higher. <6> The resin beads according to <5>, wherein the weight average molecular weight (Mw) measured by Gel Permeation Chromatography (GPC) is 8 to 20 tens of thousands. <7> The resin beads according to <5> or <6>, wherein the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by Gel Permeation Chromatography (GPC) is 1.6 to 2.5. <8> The resin beads according to any one of <5> to <7>, wherein the content of the residual chain transfer agent is 100 mass ppm or less. <9> A resin composition comprising a methacrylic resin having a proportion of structural units derived from methyl methacrylate of 95 mass% or more, a syndiotacticity expressed by a triad of 55% or more, a residual monomer content of 7000 mass ppm or less, a dimer content of monomers of 100 mass