Silicone polyimide compositions with improved flame retardance

• US 8,349,933 B2
• Filed: 07/21/2010
• Issued: 01/08/2013
• Est. Priority Date: 07/21/2010
• Status: Expired due to Fees

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: Sabic Innovative Plastics IP BV (Government of Saudi Arabia)
• Inventors: Gallucci, Robert Russell, Bhandari, Yashpal J.
• Primary Examiner(s): EGWIM, KELECHI CHIDI
• Application Number:
  US12/840,802
• Publication Number:
  US 20120021153A1
• Time in Patent Office: 902 Days
• Field of Search: 525/422, 525/100, 525/186, 525/199, 525/426, 525/431
• US Class Current: 524/422
• CPC Class Codes: C08G 73/106 containing silicon
• CPC Class Codes: C08G 77/455 containing polyamide, polyesteramide or polyimide sequences
• CPC Class Codes: C08K 3/38 Boron-containing compounds
• CPC Class Codes: C08L 2205/16 Fibres; Fibrils
• CPC Class Codes: C08L 25/12 with unsaturated nitriles
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 79/08 Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: C08L 83/10 Block- or graft-copolymers containing polysiloxane sequences obtained by polymerising a compound having a carbon-to-carbon double bond on to a polysiloxane C08L51/08, C08L53/00
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A flame retardant composition and method for making flame retardant articles. The flame retardant composition can include a silicone polyetherimide, an fibrillated polytetrafluoroethylene, and a zinc borate. The silicone polyetherimide can be present in an amount of from about 99.6 to about 80.0 percent by weight. The silicone polyetherimide can have from about 5 to about 50 percent by weight dimethyl siloxane units, and less than about 100 ppm amine end groups. The fibrillated polytetrafluoroethylene can be present in an amount of from more than about 1.25 to about 5.0 percent by weight. The fibrillated polytetrafluoroethylene can be encapsulated in a polystyrene, a poly(styrene acrylonitrile), a poly(methyl methacrylate), a polycarbonate, a polyetherimide, a polysulfone, and combinations thereof. The zinc borate can be present in an amount of more than 0 to about 10 percent by weight.

Claims

1. A flame retardant composition comprising:

a) from about 99.6 to about 80.0 percent by weight silicone polyetherimide, wherein the silicone polyetherimide has from about 5 to about 50 percent by weight dimethyl siloxane units, and less than about 100 ppm amine end groups;

b) from more than about 1.25 to about 5.0 percent by weight of a fibrillated polytetrafluoroethylene encapsulated in a component selected from the group of;

a polystyrene, a poly(styrene acrylonitrile), a poly(methyl methacrylate), a polycarbonate, a polyetherimide, a polysulfone, and combinations thereof; and

c) more than 0 to about 10 percent by weight of a zinc borate.

2. The composition of claim 1, having a flame spread index as determined by ASTM E 162, on a 3.2 mm sample, of less than 35.

3. The composition of claim 1, having a tensile strength at yield as determined by ASTM D638, on a 3.2 mm sample at 50 mm/min crosshead speed, from 2,000 to 8,000 psi.

4. The composition of claim 1, wherein the silicone polyetherimide has a weight average molecular weight from about 5,000 to about 70,000 Daltons.

5. The composition of claim 1, wherein the fibrillated polytetrafluoroethylene is encapsulated by poly(styrene acrylonitrile).

6. The composition of claim 5, wherein the poly(styrene acrylonitrile) has a weight average molecular weight of from about 100,000 to about 500,000 Daltons.

7. The composition of claim 5, wherein the poly(styrene acrylonitrile) has less than 3 percent weight loss when heated for 15 minutes at 150 degrees Celsius.

8. The composition of claim 5, wherein the encapsulated polytetrafluoroethylene is present at 30 to 60 percent by weight based on the total weight of component a).

9. The composition of claim 5, wherein the weight ratio of poly(styrene acrylonitrile) to polytetrafluoroethylene is 1:

1.

10. The composition of claim 1, comprising from more than about 1.25 to about 5.0 percent by weight of component b).

11. The composition of claim 1, comprising about 1.5 percent by weight of component b).

12. The composition of claim 1, wherein the zinc borate is selected from the group of:

anhydrous zinc borate, zinc borate mono hydrate, and mixtures thereof.

13. The composition of claim 1, wherein the zinc borate has a particle size from about 1 to about 10 microns.

14. The composition of claim 1, wherein the zinc borate has less than about 1000 ppm cadmium, mercury, or lead.

15. The composition of claim 1, wherein the zinc borate is a calcined zinc borate.

16. The composition of claim 15, wherein the calcined zinc borate has no water evolved when heated to 350 degrees Celsius.

17. The composition of claim 1, further comprising:

d) more than 0 to about 10 percent by weight of a metal oxide selected from the group of;

a titanium dioxide, a silicone dioxide, a zinc oxide, an antimony oxide, and combinations thereof.

18. The composition of claim 17, wherein the metal oxide has particle size of from about 0.1 to about 5 microns.

19. The composition of claim 1, wherein the composition has less than about 1000 ppm bromine and less than about 1000 ppm chlorine.

20. The composition of claim 1, further comprising:

e) a colorant selected from the group of;

ultramarine blue, phthalo-blue, phthalo-green solvent green 3, solvent green 28, solvent green 50, solvent blue 28, solvent blue 29, solvent blue 36, solvent red 52, solvent red 101, solvent red 151, solvent orange 63, solvent violet 13, solvent violet 36, solvent yellow 33, solvent yellow 53, solvent yellow 98, pigment red 179, pigment red 202, pigment brown 24, pigment brown 33 pigment green 7, carbon black, pigment blue 15;

4, and combinations thereof.

25. An article comprising the composition of claim 1.

26. The article of claim 25, wherein the article is at least one selected from the group of an injection molded product, a profile extruded product, and a blow molded product.

27. The article of claim 25, wherein the article comprises a metal substrate, and a layer covering at least a portion of the substrate, wherein the layer comprises the composition according to claim 1.

28. The article of claim 27, wherein the substrate is a component of an armrest.

29. The article of claim 25, wherein the article is selected from the group of a tube, a profile, a housing for an injection molded product, a pipe, a conduit, and combinations thereof.

21. A method comprising:

forming a blend comprising;

a) from about 99.6 to about 80.0 percent by weight silicone polyetherimide, wherein the silicone polyetherimide has from about 5 to about 50 percent by weight dimethyl siloxane units, and less than about 100 ppm amine end groups,

b) from about 0.3 to about 5.0 percent by weight of a fibrillated polytetrafluoroethylene encapsulated in a component selected from the group of;

a polystyrene, a polystyrene acrylonitrile), a poly(methyl methacrylate), a polycarbonate, a polyetherimide, a polysulfone, and combinations thereof, and

c) more than 0 to about 10 percent by weight of a zinc borate;

mixing the blend to form an extrudate.

22. The method according to claim 21, wherein the blend is mixed in a twin screw extruder at a die head temperature of from about 300 to about 350 degrees Celsius.

23. The method according to claim 21, further comprising cooling, pelletizing, and drying the extrudate.

24. The method according to claim 21, further comprising processing the extrudate to form a product selected from the group of an injection molded product, a profile extruded product, a blow molded product, and combinations thereof.

30. A flame retardant composition,

having a flame spread index as determined by ASTM E 162, on a 3.2 mm sample, of less than 35, and

having a tensile strength at yield as determined by ASTM D638, on a 3.2 mm sample at 50 mm/min crosshead speed, from 2,000 to 8,000 psi,

the flame retardant composition comprising:

a) from about 99.6 to about 80.0 percent by weight silicone polyetherimide, wherein the silicone polyetherimide has from about 5 to about 50 percent by weight dimethyl siloxane units, a weight average molecular weight from about 5,000 to about 70,000 Daltons, and less than about 100 ppm amine end groups;

b) more than about 1.25 to about 5.0 percent by weight of a fibrillated polytetrafluoroethylene encapsulated in a component selected from the group of;

a polystyrene, a poly(styrene acrylonitrile), a poly(methyl methacrylate), a polycarbonate, a polyetherimide, a polysulfone, and combinations thereof;

c) more than 0 to about 10 percent by weight of a zinc borate with a particle size of from about 1 to about 10 microns, having less than about 1000 ppm cadmium, mercury or lead;

d) 0 to 5 wt % of a metal oxide selected from the group of;

titanium dioxides, silicone dioxides, zinc oxides, antimony oxides or mixtures thereof, wherein the metal oxide has particle size of 0.1 to 5 microns; and

e) less than 1000 ppm bromine or chlorine.