Claims
- 1. A open cell foam, comprising;
- (A) from about 30 to about 99.5 percent by weight (based on the combined weights of Component A and B) of one or more alkenyl aromatic polymers, and wherein at least one of said alkenyl aromatic polymers has a molecular weight (M.sub.w) of from about 100,000 to about 500,000; and
- (B) from about 0.5 to about 70 percent by weight (based on the combined weight of Components A and B) of one or more substantially random interpolymers having an I.sub.2 of about 0.1 to about 50 g/10 min, an M.sub.w /M.sub.n of about 1.5 to about 20; comprising;
- (1) from about 0.5 to about 65 mol percent of polymer units derived from;
- (a) at least one vinyl or vinylidene aromatic monomer, or
- (b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
- (c) a combination of at least one aromatic vinyl or vinylidene monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and
- (2) from about 35 to about 99.5 mol percent of polymer units derived from at least one of ethylene and/or a C.sub.3-20 .alpha.-olefin; and
- (3) from 0 to about 20 mol percent of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); and
- (C) optionally, one or more nucleating agents and
- (D) optionally, one or more other additives; and
- (E) one or more blowing agents present in a total amount of from about 0.5 to about 5.0 gram-moles per kilogram (based on the combined weight of Components A and B).
- 2. The open cell foam of claim 1, wherein
- A) in Component (A), said at least one alkenyl aromatic polymer has greater than 50 percent by weight alkenyl aromatic monomeric units, has a molecular weight (M.sub.w) of from about 120,000 to about 350,000 and is present in an amount of from about 50 to about 99.5 percent by weight (based on the combined weight of Components A and B);
- B) said substantially random interpolymer, Component (B), has an I.sub.2 of about 0.3 to about 30 g/10 min and an M.sub.w /M.sub.n of about 1.8 to about 10; is present in an amount of from about 0.5 to about 50 percent by weight (based on the combined weight of Components A and B); and comprises
- (1) from about 15 to about 50 mol percent of polymer units derived from;
- (a) said vinyl or vinylidene aromatic monomer represented by the following formula; ##STR7## wherein R.sup.1 is selected from the group of radicals consisting of hydrogen and alkyl radicals containing three carbons or less, and Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C.sub.1-4 -alkyl, and C.sub.1-4 -haloalkyl; or
- (b) said sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer is represented by the following general formula; ##STR8## wherein A.sup.1 is a sterically bulky, aliphatic or cycloaliphatic substituent of up to 20 carbons, R.sup.1 is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; each R.sup.2 is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; or alternatively R.sup.1 and A.sup.1 together form a ring system; or
- c) a combination of a and b; and
- (2) from about 50 to about 85 mol percent of polymer units derived from ethylene and/or said .alpha.-olefin which comprises at least one of propylene, 4-methyl-1-pentene, butene-1, hexene-1 or octene-1; and
- (3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) comprises norbornene, or a C.sub.1-10 alkyl or C.sub.6-10 aryl substituted norbornene; and
- (C) said nucleating agent, if present, Component (C), comprises one or more of calcium carbonate, talc, clay, silica, barium stearate, calcium stearate diatomaceous earth, mixtures of citric acid and sodium bicarbonate; and
- (D) said additive, if present, Component (D), comprises one or more of inorganic fillers, pigments, antioxidants, acid scavengers, ultraviolet absorbers, flame retardants, processing aids, extrusion aids, permeability modifiers, antistatic agents, and other thermoplastic polymers;
- (E) said blowing agent, Component (E), is present in a total amount of from about 0.2 to about 4.0 g-moles/kg (based on the combined weight of Components A and B), and comprises one or more of inorganic blowing agent(s), organic blowing agent(s), and/or chemical blowing agent(s).
- 3. The open cell foam of claim 1; wherein
- (A) in Component (A), said at least one alkenyl aromatic polymer has greater than about 70 percent by weight alkenyl aromatic monomeric units, has a molecular weight (M.sub.w) of from about 130,000 to about 325,000, a molecular weight distribution, (M.sub.w /M.sub.n) of from about 2 to about 7, and is present in an amount of from about 80 to about 99.5 percent by weight (based on the combined weight of Components A and B);
- (B) said substantially random interpolymer, Component (B), has an I.sub.2 of about 0.5 to about 10 g/10 min and an M.sub.w /M.sub.n from about 2 to about 5, is present in an amount from about 0.5 to about 20 wt percent (based on the combined weight of Components A and B) and comprises
- (1) from about 30 to about 50 mol percent of polymer units derived from;
- a) said vinyl aromatic monomer which comprises styrene, .alpha.-methyl styrene, ortho-, meta-, and para-methylstyrene, and the ring halogenated styrenes, or
- b) said aliphatic or cycloaliphatic vinyl or vinylidene monomers which comprises 5-ethylidene-2-norbornene or 1-vinylcyclo-hexene, 3-vinylcyclo-hexene, and 4-vinylcyclohexene; or
- c) a combination of a and b; and
- (2) from about 50 to about 70 mol percent of polymer units derived from ethylene, or a combination of ethylene and said .alpha.-olefin, which comprises ethylene, or ethylene and at least one of propylene, 4-methyl-1-pentene, butene-1, hexene-1 or octene-1; and
- (3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) is norbornene; and
- (C) said nucleating agent, if present, Component (C), comprises one or more of talc, silica, and mixtures of citric acid and sodium bicarbonate;
- (D) said additive, if present, Component (D), comprises one or more of carbon black, titanium dioxide, graphite, flame retardants, and other thermoplastic polymers; and
- (E) said blowing agent, Component (E), is present in a total amount of from about 0.5 to about 3.0 gram-moles per kilogram (based on the combined weight of Components A and B) comprising one or more of, nitrogen, sulfur hexafluoride (SF.sub.6), argon, carbon dioxide, water, air and helium, methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, methanol, ethanol, n-propanol, and isopropanol, methyl fluoride, perfluoromethane, ethyl fluoride, ), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane (HFC-125), 1,1,2,2 tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoropropane, difluoromethane (HFC-32), perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, perfluorobutane, perfluorocyclobutane, methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloro-ethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), chlorodifluoromethane (HCFC-22), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichloro-trifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane, dichlorohexafluoropropane, azodicarbonamide, azodiisobutyro-nitrile, benzenesulfonhydrazide, 4,4-oxybenzene sulfonyl-semicarbazide, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, N,N'-dimethyl-N,N'-dinitrosotere-phthalamide. trihydrazino triazine and mixtures of citric acid and sodium bicarbonate.
- 4. The open cell foam of claim 3, wherein said alkenyl aromatic polymer, Component (A), is polystyrene, said substantially random interpolymer, Component (B), is an ethylene/styrene interpolymer, and the blowing agent, Component (E), is one or more of carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, ethanol, 1,1-difluoroethane (HFC-152a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2 tetrafluoroethane (HFC-134), ethyl chloride, 1-chloro-1,1-difluoroethane (HCFC-142b), or chlorodifluoromethane (HCFC-22).
- 5. The open cell foam of claim 3, wherein said alkenyl aromatic polymer, Component (A), is polystyrene, in said substantially random interpolymer Component B1(a) is styrene; and Component B2 is ethylene and at least one of propylene, 4-methyl-1-pentene, butene-1, hexene-1 or octene-1, and the blowing agent, Component (E), is one or more of carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, ethanol, 1,1-difluoroethane (HFC-152a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2 tetrafluoroethane (HFC-134), ethyl chloride, 1-chloro-1,1-difluoroethane (HCFC-142b), or chlorodifluoromethane (HCFC-22).
- 6. The foam of claim 1, having a density of from about 10 to about 200 kilograms per cubic meter (kg/m.sup.3) and a cell size of about 5 to about 2000 microns.
- 7. The open cell foam of claim 1, having a density of from about 15 to about 100 kg/m.sup.3 and a cell size of about 20 to about 1000 microns.
- 8. The open cell foam of claim 1, wherein the alkenyl aromatic polymer material comprises greater than about 70 percent by weight of alkenyl aromatic monomeric units, and the foam has a density of from about 10 to about 200 kilograms per cubic meter (kg/m.sup.3) and a cell size of about 5 to about 2000 microns.
- 9. The open cell foam of claim 1, wherein the alkenyl aromatic polymer material comprises greater than 70 percent by weight of alkenyl aromatic monomeric units and the foam has a density of from about 15 to about 100 kg/m.sup.3 and a cell size of about 20 to about 1000 microns.
- 10. The open cell foam of claim 1 having a water absorption value of from about 5 to about 25 g/g foam.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional application No. 60/078,091 filed on Mar. 16, 1998.
US Referenced Citations (13)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 416 815 A2 |
Mar 1991 |
EPX |