Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-03-08
2002-07-02
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C525S240000, C525S331700
Reexamination Certificate
active
06414070
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a nanocomposite composition, comprising polyolefins and organically modified clay, which exhibits flame retardant and flame resistant properties. The composition can be formed into a sheet or film. The sheet can further be utilized in a multi-layer laminate. Both sheets and laminates are flame retardant and are suitable for use as roofing membranes and protective coverings.
BACKGROUND OF THE INVENTION
Traditional flame retardants include numerous halogenated organic compounds which extinguish the ignition (flame) source and inhibit chemical decomposition in the flame and inorganic materials such as aluminum trihydrate which release volatiles such as water which cause the flame to extinguish.
U.S. Pat. No. 4,317,737 relates to polyolefin lubricant base oils which can be gelled by layer and chain type overtreated higher dialkyl dimethyl ammonium clays preferably containing a minimum of 12% excess of the quaternary ion moiety over their ion exchange capacity. For example, an overtreated dihydrogenated ditallow ammonium montmorillonite containing a 22% excess of the quaternary ion can be used to prepare a polydecene based grease although it does not gel mineral oil lubricants.
U.S. Pat. No. 4,434,075 relates to an organophilic clay gellant which comprises the reaction product of an organic cation compound, an organic anion, and a smectite-type clay having a cation exchange capacity of at lease 75 milliequivalents per 100 grams of said clay. The organic cation compound has the formula:
wherein R
1
is selected from the group consisting of a &bgr;,&ggr; unsaturated alkyl group and a hydroxyalkyl group having 2 to 6 carbon atoms and mixtures thereof; R
2
is a long chain alkyl group having 12 to 60 carbon atoms; R
3
and R
4
are individually selected from the group consisting of a &bgr;,&ggr; unsaturated alkyl group, a hydroxyalkyl group having 2 to 6 carbon atoms, an aralkyl group, an alkyl group having from 1 to 22 carbon atoms and mixtures thereof; X is selected from a group consisting of phosphorous and nitrogen. The reaction is carried out in a manner such that an organic cation-organic anion complex is intercalated with the smectite-type clay and the cation exchange sites of the smectite-type clay are substituted with the organic cation.
U.S. Pat. No. 4,582,866 relates to flame retardant thermoplastic multi-block copolyester elastomer compositions containing a bromine-containing flame retardant; antimony trioxide; and an organophilic clay which is the reaction product of at least one quaternary ammonium salt with a smectite clay.
U.S. Pat. No. 4,683,259 relates to resin-containing compositions, e.g. unsaturated polyester or epoxy resin compositions, are prepared using an organoclay of improved dispersibility. The organoclay is prepared by suspending a smectite clay in water to form a fluid suspension; treating the suspension with a solution of an inorganic salt, the cation of which has a valency of at least two, the concentration of the salt being such as to flocculate the smectite clay substantially completely; mixing the suspension of the flocculated smectite clay with a quaternary ammonium compound, at least one of the four alkyl groups of which has from 10 to 24 carbon atoms; and dewatering the resultant product.
U.S. Pat. No. 5,475,041 relates to a flame retardant composition which is provided comprising a normally flammable polyolefin or olefin copolymer, and a flame retardant amount of melamine or salt thereof, a polyphenlyene oxide and a silicaceous material.
U.S. Pat. No. 5,718,841 relates to an organophilic clay comprising the reaction product of:
(a) a smectite-type clay; and
(b) a quaternary ammonium compound or compounds selected from the group consisting of:
wherein R
1
is an unsaturated alkyl-ester group having 8 to 30 carbon atoms as described below and R
2
, R
3
and R
4
are independently selected from the group consisting of (i) R
1
; (ii) long chain linear or branched alkyl (including methyl). Aliphatic or aromatic groups having 1 to 30 carbon atoms (such groups can also include hydroxylated groups); (iii) aralkyl groups, which are benzyl and substituted benzyl moieties, including such groups having fused ring moieties having linear chains or branches of 1 to 30 carbon atoms; (iv) aryl groups such as phenyl and substituted phenyl including fused ring aromatic substitutents; (v) beta, gamma unsaturated groups having six or less carbon atoms or hydroxyalkyl groups having 2 to 6 carbon atoms ; and (vi) hydrogen; and M is an anion selected from the group consisting of chloride, methylsulfate, acetate, iodide and bromide.
U.S. Pat. No. 5,728,764 relates to organoclay compositions which comprise the reaction product of a smectite-type clay having an ion exchange capacity of at least 50 meq. wt. per 100 g. clay (active basis), and an alkoxylated quaternary ammonium compound having one or two alkoxylated chains containing 0-10 moles ethylene oxide and 3-15 moles of propylene or butylene oxide residues are useful thixotropic materials, especially for the preparation of aqueous systems.
U.S. Pat. No. 5,773,502 relates to a flame retardant composition comprising: (a) a thermoplastic polyester and copolyester material, a halogenated organic fire retardant, antimony oxide, organo clay, and a fluorocarbon polymer. Also provided are compositions comprising glass fibers and stabilizers.
SUMMARY OF THE INVENTION
Organically modified clays are distinguished from halogenated flame retardants in that the clays generally form a nanometer scale composite when mixed with polyolefins, which exhibit enhanced fire retardant properties. The resulting nanocomposites do not sag or drip when exposed to a flame source, but hold their shape and inhibit flame spreading. The nanocomposite compositions can be formed into a sheet or laminate and are suitable for numerous applications including roofing membranes.
DETAILED DESCRIPTION
Titles have been provided in this application solely for illustration and do not limit the scope of the invention in any manner.
The compositions of the present invention comprise a polyolefin material integrated with microscopic or nanosize particles of an organoclay material, which form a nanocomposite having enhanced flame retardant or resistant properties when compared to utilizing polyolefins alone. As used herein, nanocomposite is generally defined as substantially randomly dispersed particles of nanosized organoclay particles in a continuous polymeric (i.e. polyolefin) matrix.
The nanocomposites of the present invention should not be confused with ordinary compositions containing unmodified clay, i.e. natural clay and a polymer where the clay simply acts as a non-reinforcing filler, and has negligible impact on physical properties. However, the flame retardant compositions of the present invention can contain other components which also react or interact with the polymer as on a nanoscale level. The flame retardant compositions of the present invention are preferably melt processed.
POLYOLEFINS
The polyolefins utilized in the present invention are thermoplastic polymers or rubbers derived from one or more simple olefins, which have a total of from 2 to about 8 carbon atoms, or copolymers containing repeat units derived from an olefin. Carboxylic acid functionalized polyolefin polymers or copolymers can also be utilized containing up to about 8 percent by weight and preferably from about 1 percent by weight to about 5 percent by weight of the acid wherein the unsaturated acid contains a total of from 2 to about 10 carbon atoms such as acrylic acid, maleic acid, etc., or anhydrides thereof. Examples of polyolefins suitable for the present invention include polyethylene (including low-density, high-density, high molecular weight, ultra-high molecular weight, linear-low-density, very-low density, etc.), maleated polypropylene, polypropylene, polybutylene, polyhexalene, polyoctene, and copolymers, combinations or blends thereof. Examples of copolymers containing repeat units derived from olefins include but
Kausch Charles
Payne Peter F.
Peterson Kristen M.
Pomeroy, III John E.
Verrocchi Anthony
Cain Edward J.
Hudak Daniel J.
Lee Katarzyna W.
Omnova Solutions Inc.
Rywalski Robert F.
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