Process for the insertion and conveying of labile additives in streams of molten material

Patent metadata

Field	Value
Publication number	US-10183264-B2
Application number	US-201314390805-A
Country	US
Kind code	B2
Filing date	Apr 3, 2013
Priority date	Apr 6, 2012
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

The present invention relates to a process for the insertion and conveying of a labile additive, or a mixture thereof, in a transporting pipe, in which a main stream of molten material flows, said process characterized in that it incorporates said additive, or said mixture, in a portion of the pipe delimited by the main stream, according to one of the following alternative modes: a) in a longitudinal direction with respect to the flow direction of the main stream of molten material, or b) in a transversal direction with respect to the flow direction of the main stream of. molten material, or c) according to a composition of the longitudinal (a) and transversal (b) mode, thus forming a resulting stream which keeps the labile additives segregated from the main stream of molten material.

First claim

The invention claimed is:

1. A process for the insertion and conveying of a labile additive in a transporting pipe with a main molten polymeric material, comprising
providing a main stream containing molten polymeric material;
providing a secondary stream containing a labile additive, or a mixture thereof;
providing a transporting pipe;
feeding said main stream into said transporting pipe;
wherein said secondary stream has a viscosity ranging from 0.01 to 5000 Pa·s, a temperature ranging from 80 to 230° C., and a viscosity ratio between said main stream and said secondary stream is greater than 0.5, all of which is taken immediately prior to feeding into said main stream;
segregating said secondary stream and said main stream in said transporting pipe, by feeding said secondary stream according to one of the following alternative modes:
a) in a longitudinal direction with respect to the flow direction of said main stream, or
b) in a transverse direction with respect to the flow direction of said main stream, or
c) according to a combination of the longitudinal direction and the transverse direction;
transporting said secondary stream and said main stream along said transporting pipe for a residence time of at least 3 minutes, while maintaining said secondary stream and said main stream segregated;
whereby said segregation of said secondary stream and said main stream in said transporting pipe results in said labile additive, or mixture thereof, exhibiting reduced thermal and/or chemical degradation.

2. The process according to claim 1 , wherein said secondary stream containing the labile additive, or mixture thereof, is fed into the transporting pipe with continuous flow or discontinuous flow.

3. The process according to claim 1 , wherein said secondary stream containing the labile additive, or mixture thereof, is incorporated perpendicularly with respect to the flow direction of the main stream of molten material.

4. The process according to claim 1 , wherein said secondary stream containing the labile additive or mixture thereof, is incorporated in the central part of the transporting pipe.

5. The process according to claim 1 , wherein said secondary stream containing the labile additive, or mixture thereof, is incorporated by means of a side extruder or an injector.

6. The process according to claim 5 , wherein at least part of the injector is shaped so as to align said secondary stream containing the labile additive, or mixture thereof, in the direction of the main stream of molten material.

7. The process according to claim 6 , wherein said shaped part is the terminal part of the injector.

8. The process according to claim 7 , wherein the terminal part is aligned with the direction of the main stream.

9. The process according to claim 8 , wherein the length of the terminal part of the injector is at least a tenth of the hydraulic diameter of the transporting pipe.

10. The process according to claim 6 , wherein the part of the injector aligned with the direction of the main stream of molten material does not have a cylindrical section and is twisted.

11. The process according to claim 6 , wherein the part of the injector aligned with the direction of the main stream of molten material has grooves or ribs.

12. The process according to claim 1 , wherein said secondary stream containing the labile additive, or mixture thereof, is melted before being incorporated in the transporting pipe.

13. The process according to claim 1 , wherein the main stream of molten material is a molten thermoplastic polymer.

14. The process according to claim 1 , wherein mixing elements are not present in the transporting pipe.

15. The process according to claim 1 , wherein the labile additives, or mixtures thereof, are brominated and/or chlorinated organic materials.

16. The process according to claim 15 , wherein said brominated and/or chlorinated organic materials are polymeric.

17. The process according to claim 15 , wherein said secondary stream containing the labile additive, or mixture thereof, also comprises a stabilizer capable of reducing the release of bromine ions.

18. The process according to claim 1 , wherein the main stream of molten material contains one or more material chemically incompatible with said labile additive.

19. The process according to claim 18 , wherein said chemically incompatible material is an inorganic compound of carbon as element.

20. The process according to claim 19 , wherein said inorganic compound of carbon as element is coke, carbon black, graphite or graphene nanoplatelets.

21. The method of claim 1 , comprising feeding said secondary stream into said main stream with a pulsed flow.

22. The method of claim 1 , comprising transporting said secondary stream and said main stream along said transporting pipe at a slower rate for a residence time of at least 5 minutes.

23. The method of claim 1 wherein said labile additive, or Mixture thereof, includes an expanding agent.

24. The method of claim 1 wherein said reduced thermal and/or chemical degradation is not more than 305 ppm of bromide ions from said labile additive, or mixture thereof.

25. The method of claim 24 comprising transporting said secondary stream and said main stream along said transporting pipe at a slower rate for a residence time of at least 5 minutes resulting in a lower amount of said bromide ions from said labile additive, or mixture thereof.

Assignees

• Versalis Spa

Inventors

• Felisari Riccardo
• Casalini Alessandro
• Valentino Olga

Classifications

• B29C48/365

  using pumps, e.g. piston pumps · CPC title

• C08J2325/06

  Polystyrene · CPC title

• B29C48/29

  in liquid form · CPC title

• C08J3/201 Primary

  Pre-melted polymers · CPC title

• B29C48/39

  a first extruder feeding the melt into an intermediate location of a second extruder · CPC title