Crosslinking control in high impact polystyrene manufacturing process
The method includes providing a high impact polystyrene (HIPS) reaction system, wherein the HIPS reaction system has a devolitalizer downstream of a reactor and injecting a retarding agent into the HIPS reaction system prior to the devolitalizer.
1. A method comprising:
providing a high impact polystyrene (HIPS) reaction system, wherein the HIPS reaction system has a devolitalizer downstream of a reactor;
injecting a retarding agent into the HIPS reaction system prior to the devolitalizer, wherein the retarding agent comprises a free radical scavenger.
2. The method of claim 1 , wherein the retarding agent further comprises a chain transfer agent.
3. The method of claim 2 , wherein the chain transfer agent is a mercaptan, thiol, or halocarbon.
4. The method of claim 3 , wherein the chain transfer agent is a mercaptan selected from the group consisting of n-octyl mercaptan, t-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan (NDM), t-dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, n-hexadecyl mercaptan, t-nonyl mercaptan, ethyl mercaptan, isopropyl mercaptan, t butyl mercaptan, cyclohexyl mercaptan, benzyl mercaptan and mixtures thereof.
5. The method of claim 3 , wherein the chain transfer agent is carbon tetrachloride.
6. A method comprising:
providing a high impact polystyrene (HIPS) reaction system, wherein the HIPS reaction system has a devolitalizer downstream of a reactor;
injecting a retarding agent comprising a chain transfer agent into the HIPS reaction system prior to the devolitalizer, wherein the chain transfer agent is ethylbenzene, and wherein a concentration of the retarding agent in a polymer melt prior to the devolitalizer is between 50 ppm and 1000 ppm.
7. The method of claim 1 , wherein the free radical scavenger is a phenolic antioxidant.
8. The method of claim 1 , wherein the retarding agent further comprises a crosslinking coagent.
9. The method of claim 8 , wherein the crosslinking coagent is a polyfunctional (meth)acrylic monomer, allylic compound or metal salt of an unsaturated monocarboxylic acid.
10. A method comprising:
providing a high impact polystyrene (HIPS) reaction system, wherein the HIPS reaction system has a devolitalizer downstream of a reactor;
injecting a retarding agent into the HIPS reaction system prior to the devolitalizer, wherein the retarding agent is a tertiary amine oxide or a tertiary amine.
11. The method of claim 10 , wherein the retarding agent is the tertiary amine oxide, wherein the tertiary amine oxide is N,N,N-trialkylamine oxide, and wherein one N is a methyl group and the other two Ns are C 14 -C 24 saturated aliphatic chains.
12. The method of claim 10 , wherein the retarding agent is the tertiary amine oxide, and wherein the tertiary amine oxide is co-injected with an aliphatic or aromatic solvent.
13. The method of claim 12 , wherein the solvent is a heptane or ethylbenzene.
14. The method of claim 10 , wherein the retarding agent is an aromatic tertiary amine oxide.
15. The method of claim 1 , wherein the retarding agent is the tertiary amine, wherein peroxide and oxygen are present in the reaction system, and wherein the tertiary amine forms a corresponding tertiary amine oxide in the reaction system.
16. The method of claim 15 , wherein the tertiary amine is 2,6-di-tert-butyl-4-(dimethylamino)methylphenol.
17. The method of claim 1 , wherein the swell index of the HIPS 15 to 25 over that when no retardant is used.
18. The method of claim 1 , wherein the concentration of the retarding agent in a polymer melt prior to the devolitalizer is between 1 ppm and 1% (by weight).
19. The method of claim 18 , wherein the concentration of the retarding agent in the polymer melt prior to the devolitalizer is between 50 and 1000 ppm (by weight).