초록 ▼

Polyolefin-based pallets capable of passing standard pallet flammability tests are prepared by molding the pallet or one or more subassemblies thereof, of a polyolefin molding resin containing a flame retardant package containing magnesium hydroxide, and optionally alumina trihydrate, and zinc borat

Polyolefin-based pallets capable of passing standard pallet flammability tests are prepared by molding the pallet or one or more subassemblies thereof, of a polyolefin molding resin containing a flame retardant package containing magnesium hydroxide, and optionally alumina trihydrate, and zinc borate. The flame retardants may be supplied as a master batch at a concentration higher than that desired in the pallet or subassembly, in a polyolefin-compatible polymer, and result in pallets having a significantly lower heat release rate.

대표청구항 ▼

What is claimed is: 1. A flame retardant molded polyolefin pallet which is of unitary construction or which comprises two or more subassemblies, said pallet or at least one subassembly thereof comprising a polyolefin containing a flame retardant package comprising as flame retardant components a) 1

What is claimed is: 1. A flame retardant molded polyolefin pallet which is of unitary construction or which comprises two or more subassemblies, said pallet or at least one subassembly thereof comprising a polyolefin containing a flame retardant package comprising as flame retardant components a) 10-30% magnesium hydroxide, b) 0.5-8% alumina trihydrate; and c) 0.5-8% zinc borate; said percentages based on the weight of polyolefin and the sum of flame retardant components a) to c). 2. A flame retardant molded polyolefin pallet which comprises two or more subassemblies, said pallet or at least one subassembly thereof comprising a polyolefin containing a flame retardant package comprising as flame retardant components a) 8-35% magnesium hydroxide, b) optionally 0.1-10% alumina trihydrate, and c) optionally, 0.1-10% zinc borate, wherein said percentages are based on the weight of polyolefin and the sum of flame retardant components a) to c), said pallet having a polyolefin top deck containing 20-30% magnesium hydroxide, and a polyolefin bottom deck containing 10-15% magnesium hydroxide. 3. A process for the manufacture of a flame retardant polyolefin pallet or subassembly thereof, comprising a) supplying a polyolefin molding resin b) supplying a flame retardant package comprising flame retardant components b)i) magnesium hydroxide; b)ii) alumina trihydrate; and b)iii) zinc borate; c) uniformly blending said polyolefin resin with the components b)i to b)iii of said flame retardant package to form a flame retardant-containing polyolefin molding resin; and d) molding a polyolefin pallet or subassembly thereof from said flame retardant-containing polyolefin molding resin; wherein said flame retardant components are supplied in a master batch of a polymer resin containing said flame retardant components in an amount higher than the amount desired in said pallet or subassembly thereof, and supplying sufficient polyolefin to reduce the level of said flame retardant components to the range of 10-15% b)i), 0.1-8% b)ii), and 0.1-8% b)iii). 4. A process for the manufacture of a flame retardant polyolefin pallet or subassembly thereof, comprising a) supplying a polyolefin molding resin b) supplying a flame retardant package comprising flame retardant components b)i) from 8-35% magnesium hydroxide; b)ii) optionally from 0.1-10% alumina trihydrate; and b)iii) optionally from 0.1-10% zinc borate; c) uniformly blending said polyolefin resin with the components b)i to b)iii of said flame retardant package to form a flame retardant-containing polyolefin molding resin; and d) molding a polyolefin pallet or subassembly thereof from said flame retardant-containing polyolefin molding resin; wherein said pallet comprises at least a top deck and a bottom deck, optionally having a plurality of columns between said top deck and said bottom deck, at least one of said top deck, said bottom deck, or said columns being molded from a polymer of different flammability characteristics than another of said top deck, bottom deck, or columns. 5. The process of claim 4, comprising molding said top deck of said flame retardant-containing polyolefin molding resin, such that said top deck contains from 20 to 30 weight percent magnesium hydroxide. 6. The process of claim 4, further comprising constructing said top deck or a portion thereof of a non-polyolefin polymer which exhibits greater inherent flammability resistant characteristics than polyolefin. 7. A flame retardant polymer master batch suitable for addition to a polyolefin molding resin to prepare a pallet or subassembly thereof, said master batch comprising 35 weight percent or more magnesium hydroxide, optionally 12 weight percent or more of alumina trihydrate; 12 weight percent or more of zinc borate, and at least 10 weight percent of a polymer which is compatible with polyolefin in injection molding. 8. The master batch of claim 7, wherein said polyolefin comprises polypropylene. 9. The master batch of claim 7, further containing at least one further flame retardant additive or intumescent, and being substantially free of halogenated flame retardants. 10. A flame retardant molded polyolefin pallet which is of unitary construction or which comprises two or more subassemblies, said pallet or at least one subassembly thereof comprising a polyolefin containing a flame retardant package comprising as flame retardant components a) 8-35% magnesium hydroxide, b) optionally 0.1-10% alumina trihydrate, and c) 0.1-10% zinc borate, wherein said percentages are based on the weight of polyolefin and the sum of flame retardant components a) to c).