Fire retardant systems for polymers that enable flexibility and strength
View Patent ↗The present invention relates to advanced flame/fire retardant compositions for fabric, upholstery, carpet, barrier, automotive, building construction, communication, and consumer electronics applications. The flame retardant composition comprises: about 5-25 wt. % hydrogenated styrenic block copolymer, about 6-40 wt. % polyolefin, about 50-80 wt. % inorganic flame retardant, about 0-5 wt. % coating, about 0-5 wt. % functionalized styrenic block copolymer, about 0-7 wt. % agri-derived heat resistant liquid, about 0.05-1.0 wt. % antioxidant, and about 0-7 wt. % optional additives such as metal deactivator, colorant, filler, and/or lubricants, wherein said composition totals 100 wt. %. An article made from the flame retardant composition, such as film, fiber, cable, and wire insulation meets various European and U.S. standards. The flame retardant compositions possess a good balance of tensile strength, elongation, flame resistance, and processability that has previously been unobtainable.
1. A flame retardant composition comprising:
from about 5 to about 18 wt. % of a hydrogenated styrenic block copolymer wherein said hydrogenated styrenic block copolymer is a mixture of SEBS and functionalized SEBS, formed sequentially or radially,
from about 6 to about 40 wt. % of a polyolefin,
from about 50 to about 80 wt. % of a mixture of one or more inorganic flame retardants with one or more coated inorganic flame retardants, with at least 10 wt. % of said mixture being coated inorganic flame retardant, and
from about 0.05 to about 1.0 wt. % of an antioxidant,
wherein said coated inorganic flame retardant comprises a mixture of at least two groups of blended particles, each group with a different coatings, wherein said coating comprises from about 0.2 wt. % to about 5 wt. % of the inorganic flame retardant,
wherein said composition totals 100 wt. %,
wherein said composition has a melt flow rate>1.5 g/10 min. measured at 200° C. and 2.16 kg mass, and
wherein said composition has a tensile strength greater than 10 MPa when measured in accordance with ASTM D412.
2. The flame retardant composition of claim 1 , wherein said polyolefin is a polyolefin homo-polymer, a polyolefin copolymer, a functionalized polyolefin, a polyolefin elastomer, or a mixture of 2 or more of these.
3. The flame retardant composition of claim 2 , wherein the functionalized polyolefin is functionalized with maleic anhydride, said polyolefin elastomer is a C 5 -C 9 hydrocarbon with either ethylene or propylene, and said homopolymer is polypropylene or polyethylene.
4. The flame retardant composition of claim 1 , wherein said polyolefin homopolymer is LLDPE, LDPE, or HDPE, or a mixture of 2 or more of these.
5. The flame retardant composition of claim 1 , wherein said flame retardant is selected from the group consisting of aluminum hydroxide, gibbsite, bayesite, nordstrandite and doylite, magnesium hydroxide, huntite, brucite, hydromagnesite, and a mixture of 2 or more of these.
6. The flame retardant composition of claim 1 , wherein said coated inorganic flame retardant is coated with silane, stearate, non-polar non-functionalized polymeric coating, siloxane compounds, or a mixture of 2 or more of these.
7. The flame retardant composition of claim 6 , wherein said coated inorganic flame retardant is formed in-situ by the addition of said coating during dry blending of the composition, or blending into the inorganic flame retardant during melt processing.
8. The flame retardant composition of claim 1 , wherein said functionalized SEBS is grafted with a monomer acid or its derivatives, wherein suitable monomer acids or their derivatives include maleic acid, succinic acid, itaconic acid, fumaric acid, and acrylic acid.
9. The flame retardant composition of claim 1 , wherein said antioxidant is a hindered phenolic antioxidant such as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydro-cinnamate)]methane; a secondary phosphite stabilizer such as tris(2,4-di-tert-butylphenyl); or a thio co-stabilizer such as dilauryl-thiodiproprionate or a mixture of 2 or more of these.
10. The flame retardant composition of claim 1 , wherein said hydrogenated block copolymer is of the formula ABA, (A-B) n X, or (A-B-A) n X where n is an integer from 2 to about 30, and X is a coupling agent residue, the hydrogenated block copolymer having a number average molecular weight of from about 70 kg/mol to about 150 kg/mol and comprising at least two polymer blocks (A) composed mainly of a vinyl aromatic compound and at least one hydrogenated polymer block (B) composed of a conjugated diene compound, the A block contains a number average weight from about 5.0 to about 7.5 kg/mol wherein the B block contains a controlled distribution of styrene.
11. The flame retardant composition of claim 10 , wherein said controlled distribution of styrene is from about 10 wt. % to about 40 wt. %.
12. The flame retardant composition of claim 10 , further comprising the hydrogenated block copolymer having a MFR of about 43 g/10 min. at 230° C. and 2.16 kg.
13. The flame retardant composition of claim 10 , wherein said inorganic flame retardant is selected from the group consisting of aluminum hydroxide, gibbsite, bayesite, nordstrandite and doylite, magnesium hydroxide, huntite, brucite, hydromagnesite, and a mixture of 2 or more.
14. The flame retardant composition of claim 10 having a tensile strength greater than 10 MPa when measured in accordance with ASTM D412.
15. The flame retardant composition of claim 1 , consisting of the hydrogenated styrenic block copolymer, the polyolefin, the mixture of one or more inorganic flame retardants with one or more coated inorganic flame retardants, the antioxidant, optionally, up to 7 wt. % of an additive selected from the group consisting of a metal deactivator, a colorant, a filler, a lubricant, or a combination thereof, and optionally, up to 7 wt. % of an agri-derived heat resistant liquid.