Source: https://patents.google.com/patent/US9359481B2/en
Timestamp: 2018-04-26 23:51:34
Document Index: 767620991

Matched Legal Cases: ['art 5', 'Application No. 04811960', 'Application No. 06800020', 'Application No. 2004295331', 'Application No. 2005323239', 'Application No. 2005323239', 'Application No. 2', 'Application No. 2', 'Application No. 2', 'Application No. 2', 'Application No. 200480035089', 'Application No. 200480035089', 'Application No. 200480035089', 'Application No. 200480035089', 'Application No. 200580046678', 'Application No. 200580046678', 'Application No. 200580046678', 'Application No. 200580046678', 'Application No. 1139', 'Application No. 1139', 'Application No. 2006', 'Application No. 2007', 'Application No. 2007', 'Application No. 2006', 'Application No. 2007', 'Application No. 06', 'Application No. 06', 'Application No. 07', 'Application No. 547']

US9359481B2 - Thermoplastic foams and method of forming them using nano-graphite - Google Patents
Thermoplastic foams and method of forming them using nano-graphite Download PDF
US9359481B2
US9359481B2 US12769144 US76914410A US9359481B2 US 9359481 B2 US9359481 B2 US 9359481B2 US 12769144 US12769144 US 12769144 US 76914410 A US76914410 A US 76914410A US 9359481 B2 US9359481 B2 US 9359481B2
US12769144
US20110064938A1 (en )
Raymond Breindel
Joseph P. Rynd
Mark E. Polasky
Rigid foam insulating products and processes for making such insulation products are disclosed. The foam products are formed from a polymer, a blowing agent, and nano-graphite. The nano-graphite has a size in at least one dimension less than about 100 nm and, in exemplary embodiments may be an intercalated, expanded nano-graphite. In addition, the nano-graphite may include a plurality of nanosheets having a thickness between about 10 to about 100 nanometers. The nano-graphite acts as a process additive to improve the physical properties of the foam product, such as thermal insulation and compressive strength. In addition, the nano-graphite in the foam controls cell morphology and acts as a nucleating agent in the foaming process. Further, the nano-graphite exhibits overall compound effects on foam properties including improved insulating value (increased R-value) for a given thickness and density and improved ultraviolet (UV) stability.
This application claims the benefit of prior applications U.S. patent application Ser. No. 10/722,929 entitled “Method Of Forming Thermoplastic Foams Using Nano-Particles To Control Cell Morphology” filed on Nov. 26, 2003, and U.S. patent application Ser. No. 11/481,130 entitled “Polymer Foams Containing Nano-Graphite” filed on Jul. 5, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 11/026,011 entitled “Polymer Foams Containing Nano-Graphite” filed Dec. 31, 2004 (now U.S. Pat. No. 7,605,188), the entire contents of each of which are expressly incorporated herein.
The present invention relates generally to foam products, and more particularly, to rigid foamed polymeric boards containing nano-graphite. The nano-graphite is added to provide benefits as a process aid, an R-value enhancer, UV radiation stability enhancer, a dimensional stability enhancer, a mechanical strength enhancer, and as a fire retardant. The added nano-graphite also is added to reduce foam surface static, to function as internal lubricant in the foaming process, and to control the cell morphology. A wide range of cell morphologies may be obtained by utilizing nano-particles as nucleating agents. Such rigid foams are useful for forming rigid insulating foam boards suitable in many conventional thermal insulation applications.
In the past, infrared attenuating agents (IAAs) such as carbon black powdered amorphous carbon, graphite, and titanium dioxide have been used as fillers in polymeric foam boards to minimize material thermal conductivity which, in turn, will maximize insulating capability (increase R-value) for a given thickness. R-value is defined as the commercial unit used to measure the effectiveness of thermal insulation. A thermal insulator is a material, manufactured in sheets, that resists conducting heat energy. Its thermal conductance is measured, in traditional units, in Btu's of energy conducted times inches of thickness per hour of time per square foot of area per Fahrenheit degree of temperature difference between the two sides of the material. The R value (per inch) of the insulator is defined to be 1 divided by the thermal conductance per inch. R is an abbreviation for the complex unit combination hr·ft2·° F./Btu. In SI units, an R value of 1 equals 0.17611 square meter Kelvin per watt (m2·K/W).
The heat transfer through an insulating material can occur through solid conductivity, gas conductivity, radiation, and convection. The total thermal resistance, R, (sometimes called R-value) is the measure of the resistance to heat transfer, and is determined as: R=t/k, where, t=thickness.
Rigid foamed plastic boards are extensively used as thermal insulating materials for many applications. It is highly desirable to improve the thermal conductivity without increasing the density, and/or the thickness of foam product. Particularly, the architectural community desires a foam board having a thermal resistance value of R=10, with a thickness of less than 1.8″, for cavity wall construction, to keep at least 1″ of the cavity gap clean.
It is also desirable to improve the UV stability, particularly for such as exterior wall insulation finishing system (EIFS), and highway and railway underground applications where prolonged exposure of sun light of the surface of the polymer foam boards are usually occurred in job-sites.
The physical properties of rigid polymer foam boards, such as their compressive strength, thermal conductivity, dimensional stability, water absorption rate, depend in large part on the micro-structure of the material forming the boards, i.e., the cell morphology of the foam. However, it can be difficult to control polymer foaming to the degree necessary for consistent production of a desirable cell morphology that will tend to optimize the overall foam properties, or to improve a specific property, such as the thermal insulation value of the foam
Prior art attempts to make foam micro-structures having desirable cell morphologies have included the use of nucleation agents such as powders formed from inorganic oxides, various organic materials and metals. Among these nucleation agents, the inorganic oxides, such as talc, titanium dioxide and kaolin, are the most commonly used. The size, shape, particle distribution and surface treatment of the nucleation agent(s) utilized in the process to form a foam will all tend to affect the nucleation efficiency and, consequently, the cell size morphology and distribution in the resulting foam.
Conventional methods for controlling the cell morphology, however, tend to be limited by difficulties in evenly distributing particles of the nucleation agent throughout the polymer and/or suppressing coagulation of the dispersed particles. Certain structural defects in the resulting foams are generally attributed, at least in part, to dimensional differences between the particles of the nucleating agents, which may be in the range of several microns, particularly in situations where there has been some degree of coagulation, and the desired cell microstructures, which may have a target cell wall thickness in the range of 0.2 to 6 microns, often one micron or less, for low density commercial insulation foams.
This size difference between the nucleation agent particles and the cell wall thickness may also result in relatively weak interactions between the nucleating agent and nano-scale polymer, thereby weakening the overall foam structure. Similarly, cell defects may also be attributed, at least in part, to the hydrophilic surface of most conventional inorganic nucleation agents that makes them difficult to disperse evenly in a polymer. These effects tend to result in processing difficulties, such as corrugation of the resulting foam board, when nucleation agents are added at levels greater than about 2 weight percent or the median cell size of the resulting foam is less than around 120 microns.
Prior art attempts to avoid foam structure corrugation effects have utilized cell size enlarging agents such as the waxy compositions disclosed in U.S. Pat. No. 4,229,396, the contents of which are hereby incorporated by reference in their entirety, and the non-waxy compositions disclosed in U.S. Pat. No. 5,489,407, the contents of which are hereby incorporated by reference in their entirety.
Another effort directed toward foam structures having bi-modal cell morphology (Kanelite Super EIII, Kaneka, Japan) included use of immiscible blowing agents, such as water and hydrocarbon. This combination, however, tends to result in processing difficulties due to the low solubility of water in the polymer and the reaction of water with fire retardant, such as hexabromocyclododecane (HBCD) at the elevated temperatures typically utilized during the extrusion process.
Thus, there is a need for foam products, more specifically rigid foam boards, utilizing nano-graphite particles having at least one dimension—usually the thickness of the plate shaped graphite in nano-scale, i.e., less than 0.1 microns or 100 nanometers. It is a further object of the present invention to provide a process for preparing low density extruded polymer foams and foam boards containing nano-graphite which has good processing properties, and improved foam physical properties, including thermal conductivity, ultraviolet (UV) radiation resistance, dimensional stability, mechanical strength, flame spread rate and smoke density.
The present invention relates to foam insulating products and the processes for making such products, such as extruded polystyrene foam, that contains nano-graphite as a process additive to improve the physical properties such as thermal insulation and compressive strength. During foaming, nano-graphite acts as a nucleating agent and lubricant. Lubrication by the nano-graphite makes the flow of the melted polymer in the extruder easier, and provides a smooth surface to the foam board. Further, the nano-graphite reduces the amount of static present during the foaming process due to the increased electric conductivity of the skin of the nano-graphite polymer foam boards. Nano-graphite in a foam product also acts as a UV stabilizer and as a gas barrier in the final product.
The nano-particles (e.g., nano-graphite) are typically particles with at least one dimension less than 100 nm and may be incorporated into the polymer as surface modified nano-particles, nano-particles having mechanochemical bonds to a core micron sized particle, nano-particle compounds in combination with polymers, such as master batch compositions, and/or liquid blowing agents. Further, the nano-particle polymer compounds can be intercalated nano-layers, such as compounds formed simply by mixing nano-montmorillonite (MMT) or expanded graphite with a polymer, or exfoliated nano-layers, such as compounds formed by the in-situ polymerization of polymer precursors in the presence of nano-MMT or nanosheets or other surface-modified inorganic or graphite particles.
It is an object of the present invention to produce a rigid polymer foam containing nano-graphite which exhibits overall compound effects on foam properties including improved insulating value (increased R-value) for a given thickness and density, and ultraviolet (UV) stability.
It is another object of the present invention to produce a rigid polymer foam containing nano-graphite having retained or improved compressive strength, thermal dimensional stability and fire resistance properties.
It is yet another object of the present invention to provide nano-graphite in a rigid polymer foam which also acts as a process additive which control the cell morphology, reduces static and provides lubrication during the foaming process.
It is a further object of the present invention to lower the cost of a polymeric foam product in a simple and economical manner, such as by using nano-graphite as a low cost, functional colorant.
Additionally, the present invention provides a process for making a closed-cell, alkenyl aromatic polymer foam product in which nano-particle nucleation agents are utilized to control the cell morphology. The exemplary process includes: 1) heating an alkenyl aromatic polymer to the temperature above the glass transition temperature of the polymer (for amorphous polymer), or melt point of the polymer (for crystal polymer) to form a polymer melt; 2) incorporating an appropriate amount of selected nano-particles (e.g. nano-graphite) into the polymer melt to alter the polymer property and process behavior, such as rheology, melt strength; 3) incorporating blowing agents into the polymer melt at elevated pressure; 4) incorporating other additives, such as flame retardants into the polymer melt; and 5) extruding and forming a foam product, typically a rigid insulation board, under an atmospheric or sub-atmospheric pressure (partial vacuum) to produce a desired cell morphology, characterized by parameters such as cell size range and distribution, cell orientation and cell wall thickness.
One exemplary embodiment of the present invention provides a process for making a rigid polymer foam having a mean cell size ranging from several tens of microns to several hundred microns, preferably around 60 microns, by using surface modified hydrophobic nano-particles (e.g. nano-graphite). Conventional foams, in comparison, tend to have a median cell size of more than 150 microns produced by using conventional inorganic nucleating agents such as hydrophilic talc. The rigid foams prepared according to this exemplary embodiment of the invention exhibited no detectable corrugation and an improvement in compressive strength of around 30%.
A further exemplary embodiment of the present invention provides a process for forming an improved foam structure using a carbon dioxide blowing agent in combination with a nano-scale nucleating agent, such as nano-MMT, to produce a rigid foam having a reduced median cell size and thinner cell walls both to improve mechanical strength and decrease thermal conductivity (thereby increasing the insulation value) of the resulting foam.
FIG. 1 is a graphical illustration depicting the density and compressive modulus of polystyrene foam and polystyrene foams containing nano-graphite;
FIG. 2 is a graphical illustration comparing the rheology of pure polystyrene foam and polystyrene foam containing nano-graphite;
FIG. 3 is a scanning electronic microscope (SEM) image of the foam cells of the present invention;
FIG. 4 is a scanning electronic microscope (SEM) image of the foam cell walls and struts;
FIG. 5 is a graphical illustration comparing a polystyrene foam board to the nano-graphite/polystyrene board of the present invention when both boards are exposed to UV radiation;
FIG. 6 is a scanning electron microscope (SEM) image of the cell wall structure of a typical extruded polystyrene (XPS) foam;
FIG. 7 is an SEM image of the cell strut structure of a typical extruded polystyrene (XPS) foam;
FIG. 8 is an SEM image of an XPS foam with average cell size of about 81 microns produced with about 0.5% of a nano-clay nucleating agent;
FIG. 9 is an optical microscope image of the cell size, cell size distribution, and cell orientation (x/z) of an XPS foam with 2% nano-calcium carbonate;
FIG. 10 is an optical microscope image of the cell size, cell size distribution, and cell orientation (x/z) of an XPS foam with 3.3% of a nano-expanded graphite nucleating agent; and
FIG. 11 is an SEM cell morphology image of an XPS foam sample prepared using 5% nano-MMT as a nucleating agent and 6% CO2 as a blowing agent.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All references cited herein, including published or corresponding U.S. or foreign patent applications, issued U.S. or foreign patents, or any other references, are each incorporated by reference in their entireties, including all data, tables, figures, and text presented in the cited references. In the drawings, the thickness of the lines, layers, and regions may be exaggerated for clarity.
The above objects have been achieved through the development of polymer foam products which contains nano-graphite to control cell morphology and act as a gas diffusion barrier. The foam products exhibit improved thermal insulation (R-values), the nano-graphite acting as an infrared attenuating agent and a cell nucleating agent. The nano-graphite in the foam also serves as an internal lubricant during processing of the foam and permits the release of surface static during processing of the foam. Foams containing nano-graphite, of the present invention, also have increased dimensional stability.
The present invention particularly relates to the production of a rigid, closed cell, polymer foam board prepared by extruding process with nano-graphite, at least one blowing agent and, optionally, other additives.
The rigid foamed plastic materials may be made of any such materials suitable to make polymer foams, which include polystyrenes, polyolefins, polyvinylchloride, polycarbonates, polyetherimides, polyamides, polyesters, polyvinylidene chloride, polymethylmethacrylate, polyurethanes, polyurea, phenol-formaldehyde, polyisocyanurates, phenolics, copolymers and terpolymers of the foregoing, including for example, styrene-acrylonitrile (SAN) and acrylonitrile-butadiene-styrene (ABS), thermoplastic polymer blends, rubber modified polymers, and the like. Suitable polyolefins include polyethylene and polypropylene, and ethylene copolymers.
A preferred thermoplastic polymer comprises an alkenyl aromatic polymer material. Suitable alkenyl aromatic polymer materials include alkenyl aromatic homopolymers and copolymers of alkenyl aromatic compounds and copolymerizable ethylenically unsaturated comonomers. The alkenyl aromatic polymer material may further include minor proportions of non-alkenyl aromatic polymers. The alkenyl aromatic polymer material may be comprised solely of one or more alkenyl aromatic homopolymers, one or more alkenyl aromatic copolymers, a blend of one or more of each of alkenyl aromatic homopolymers and copolymers, or blends of any of the foregoing with a non-alkenyl aromatic polymer. Suitable polymers generally have weight-average molecular weights from about 30,000 to about 500,000.
Suitable alkenyl aromatic polymers include those derived from alkenyl aromatic compounds such as styrene, alpha-methylstyrene, ethylstyrene, vinyl benzene, vinyl toluene, chlorostyrene, and bromostyrene. Minor amounts of monoethylenically unsaturated compounds such as C2-6 alkyl acids and esters, ionomeric derivatives, and C4-6 dienes may be copolymerized with alkenyl aromatic compounds. Examples of copolymerizable compounds include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, itaconic acid, acrylonitrile, maleic anhydride, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, vinyl acetate and butadiene. In one or more exemplary embodiments, the alkenyl aromatic polymer is substantially polystyrene (i.e., at least 80%, even 95% polystyrene), and may be composed completely of polystyrene.
The nano-graphite used in this invention has at least one dimension, most likely the thickness of the particle, less than about 100 nanometers, which may be measured by X-ray diffraction. Other dimensions of particles may be less than about 100 microns, less than about 50 microns, or less than about 20 microns. The foam may comprise nanosheets of exfoliated graphite dispersed in the polymeric matrix. Exfoliated graphite is graphite that has been intercalated, preferably by an oxidation process, where the atoms or molecules have been inserted into the inter-planar spacing between the layered planes of carbons, and expanded. The intercalated graphite is expanded or exfoliated preferably by brief exposure to high heat to expand the thickness of the graphite. The expanded or exfoliated graphite is then mixed with monomers and polymerized in situ to form a polymer with a network of nanosheets of the exfoliated graphite dispersed therein.
The exfoliated graphite advantageously retains its nanostructure during the polymerization process. The expanded or exfoliated graphite is compressed together into flexible thin sheets. The nano-graphite in the foam comprises a plurality of nanosheets typically in layers, where each layer may comprise few or even a single carbon layer. The nanosheets have a thickness of between about 10 to several hundred nanometers, with majority in the range from about 10 to about 100 nanometers. Detailed explanation of graphite exfoliation may be found in Graphite Intercalation Compounds I: Structure and Dynamics, H. Zabel; S. A. Solin (1990) and Carbon and Graphite Handbook, C. L. Mantell (1968), which are herein incorporated by reference.
Nano-graphite is added in an amount from preferably greater than 0% to about 10% by weight, e.g. from about 0.01% to about 10% by weight or about 0.05% to about 5% by weight, with exemplary preferred ranges from about 0.5% to about 5% by weight or from about 0.5% to about 3% by weight or from about 0.05% to about 2.5% by weight.
In mixing the graphite with the polystyrene monomer, as discussed above, it is important to have uniform distribution of the graphite. As such, the surface of the acid treated graphite, as mentioned above, may be functionalized with glycidyl methacrylate (“GMA”).
The multi-layered nano-graphite may also be melted and blended with polymer carriers, such as polystyrene, polymethyl methacrylate (“PMMA”) and ethyl methacrylate (“EMA”). The loading can be as high as 40%. Mixing temperature is about 150 to about 300° C., typically about 225° C. for EMA, and mixing time about 0 to about 3 minutes, typically less than one minute for EMA carrier containing 40 percent by weight nano-graphite, are crucial for effective dispersing of nano-graphite throughout the polymer. Mixing may be conducted by any standard method know in the art. In an embodiment, the components are mixed using a Banbury mixer.
Blowing agents and other optional additive agents are described below in connection with the process and/or in examples. Further properties of the foam products are also described below.
In another aspect, the present invention relates to a process for preparing a foam product involving the steps of forming a foamable mixture of (1) polymers having weight-average molecular weights from about 30,000 to about 500,000, (2) nano-graphite, as previously described, (3) at least one blowing agent, and, optionally, (4) other process additives, such as a nucleation agent, flame retardant chemicals, foaming the mixture in a region of atmosphere or reduced pressure to form the foam product. In one embodiment, the polymer is polystyrene having weight-average molecular weight of about 250,000.
Standard extrusion processes and methods which may be used in the process of manufacturing the invention are described in commonly owned U.S. Pat. No. 5,753,161, which is herein incorporated by reference in its entirety. Detailed descriptions of foaming methods, including expansion and extrusion can be found in Plastics Processing Data Handbook (2nd Edition), Rosato, Dominick© 1997 Springer-Verlag which is herein incorporated by reference.
In the extrusion process, an extruded polystyrene polymer, nano-graphite foam is prepared by twin-screw extruders (low shear) with flat die and plate shaper. Alternatively, a single screw tandem extruder (high shear) with radial die and slinky shaper can be used. Nano-graphite is then added into the extruder in an amount from preferably greater than 0% to about 10% by weight, e.g. from about 0.01% to about 10% by weight or about 0.05% to about 5% by weight or more preferably from about 0.5% to about 5% or from about 0.5% to about 3% or from about 0.05% to about 2.5% by weight, based on the weight of the polymer along with the polymer(s) (e.g., polystyrene), a blowing agent, and optionally, other additives such as those described below. In exemplary embodiments, an extruded polystyrene polymer foam is prepared by twin-screw extruders (low shear) with flat die and plate shaper. The nano-graphite compound may be added into the extruder via multi-feeders, along with polystyrene, a blowing agent, and/or other additives.
The plasticized resin mixture containing nano-graphite, polymer, and other optional additives is heated to the melt mixing temperature and thoroughly mixed. The melt mixing temperature must be sufficient to plasticize or melt the polymer. Therefore, the melt mixing temperature is at or above the glass transition temperature or melting point of the polymer. Generally, the melt mix temperature is from about 200 to about 250° C., most preferably about 220 to about 240° C. depending on the amount of nano-graphite.
Next, a blowing agent (described further below) is incorporated to form a foamable gel. The foamable gel is then cooled to a die melt temperature. The die melt temperature is typically cooler than the melt mix temperature, and in exemplary embodiments, is from about 100° C. to about 130° C., and preferably about 120° C. The die pressure should be sufficient to prevent prefoaming of the foamable gel, which contains the blowing agent. Prefoaming involves the undesirable premature foaming of the foamable gel before extrusion into a region of reduced pressure. Accordingly, the die pressure varies depending upon the identity and amount of blowing agent in the foamable gel. In exemplary embodiments, the pressure is from about 50 to about 80 bars, most preferably about 60 bars. The expansion ratio, foam thickness per die gap, is in the range of about 20 to about 70, typically about 60. FIG. 2 illustrates a comparison of viscosity (eta* in Pa-sec) between grade 1600 polystyrene from NOVA Chemical, PA and the same polystyrene with 1 wt % of nano-graphite additive at regular die shear rate range (around 100 rad/sec frequency). In the regular die temperature operation range, from 115 to 125° C., the viscosity of the polystyrene with nano-graphite is higher, but is manageable within the operation temperature window.
Any suitable blowing agent and combinations of blowing agents may be used in the practice on this invention. Blowing agents useful in the practice of this invention may be selected from: 1) organic blowing agents, such as aliphatic hydrocarbons having 1-9 carbon atoms (including, for example, methane, ethane, propane, n-butane, isobutane, isopentane, n-pentane, isopentane, neopentane and cyclopentane) and fully or partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms (see below) and aliphatic alcohols, ketones, esters and ethers having 1-3 carbon atoms (e.g. methanol, ethanol, n-propanol, and isopropanol; and acetone, methylformate, and dimethylether); 2) inorganic blowing agents, such as carbon dioxide, nitrogen, water, air, argon, nitrogen, and helium; and 3) chemical blowing agents, such as azodicarbonamide, azodiisobutyro-nitrile, benzenesulfonhydrazide, 4,4-oxybenzene sulfonyl-semicarbazide, p-toluenesulfonyl, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, and N,N′-dimethyl-N,N′-dinitrosoterephthalamide and trihydrazino triazine.
Exemplary halogenated aliphatic hydrocarbon blowing agents include fluorocarbons, chlorocarbons and chlorofluorocarbons. Examples of partially or fully halogenated fluorocarbons include methyl fluoride, difluoromethane (HFC-32), perfluoromethane, ethyl fluoride (HFC-161), 1,2-difluoroethane (HFC-142), 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoro-ethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), perfluoroethane, 2,2-difluoropropane (HFC-272fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1,1,3,3-pentafluoropropane (HFC 245fa), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), perfluoropropane, 1,1,1,3,3-pentafluorobutane (HFC-365mfc), perfluorobutane, and perfluorocyclobutane. Examples of partially halogenated chlorocarbons and mixed, chlorofluorocarbons for use in this invention include methyl chloride, methylene chloride, chlorodifluoromethane (HCFC-22), ethyl chloride, 1,1,1-trichloroethane, 1,1,1-trifluoroethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), pentafluoroethane, dichloropropane, and the like. Examples of fully halogenated chlorofluorocarbons include trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane, and dichlorohexafluoropropane.
Particularly useful blowing agents include 1-chloro-1,1-difluoroethane (HCFC-142b), 1,1,1,2-tetrafluoro-ethane (HFC-134a), carbon dioxide, and 1,1-difluoroethane (HFC-152a); and blends of these: e.g. HCFC-142b with carbon dioxide, HFC-134a with carbon dioxide, carbon dioxide with ethanol, carbon dioxide with water, and HFC-134a with HFC-152a. About 50% of the HFC-134a blowing agent and about 50% of the HFC-152a blowing agent may be present in the composition. Both components are based on the weight of the polymer. However, for low density, thick products, the amount of HFC-152a may be increased up to about 60% or more based on the weight of the polymer.
In the present invention, it is preferable to use about 6 to about 14%, preferably about 11%, by weight based on the weight of the polymer of the blowing agent (e.g. cyclopentane). If used, it is also preferred to add about 0 to about 4% ethanol and/or about 3 to about 6%, preferably about 3.5% carbon dioxide. All percentages are based on the weight of the polymer.
Optional additives may be incorporated in the extruded foam product and may include, but are not limited to, additional infrared attenuating agents, cell size enlarging agents, plasticizers, flame retardant chemicals, pigments, elastomers, extrusion aids, antioxidants, fillers, antistatic agents, UV absorbers, citric acids, nucleating agents, surfactants, processing aids, and mold release aids. These optional additives may be included in any amount to obtain desired characteristics of the foamable gel or resultant extruded foam products and/or to improve the processing of the foam or modify one or more properties of the resulting foam. Preferably, optional additives are added to the resin mixture but may be added in alternative ways to the extruded foam manufacture process.
Although the polymer foams manufactured according to the present invention may have structures exhibiting both closed cells and open cells, preferred foam compositions will have at least 90 percent closed cells as measured according to ASTM D2856-A. Exemplary embodiments of polymer foam products manufactured according to the present invention can exhibit densities of from about 10 to about 500 kg/m3, but will more preferably have densities of from about 20 to about 60 kg/m3 when measured according to ASTM D-1622. For a preferred rigid, foam insulation board as described herein, the density is generally about 20-80 kg/m3 (about 1.2-5 pcf), typically about 22-48 kg/m3 (about 1.4 to about 3 pcf); and is about ⅛ to about 12 inches thick, typically about 1 to about 4 inches thick. The resulting board exhibits an R-value (per inch) of from about 3 to about 8.
As mentioned above, the nano-graphite in the foam controls cell morphology. The nano-scale graphite acts as a nucleating agent in the foaming process. The cell morphology includes parameters such as cell mean size, cell anisotropic ratio or cell orientation, cell density, cell size distribution, cell wall thickness, cell strut effective diameter, open/closed cell ratio, cell shape, such as pentagonal dodecahedral, rhombic dodecahedron, tetra dodecahedral (with curved surface), and other models of cells such as bi-cell and cell-in-cell models. Within these cell morphology parameters, cell mean size, cell wall thickness, cell strut effective diameter, and cell orientation are key parameters for determining the foam physical properties of closed cell foams.
The invention uses nano-particles such as nano-graphite and the above-described extrusion process to control the cell size, cell wall thickness, strut effective diameter, and cell orientation of the foam products within a relatively broad range. As discussed above, the particle size of the present nano-particle cell size controlling agent (e.g. nano-graphite) is typically no greater than 100 nanometers in at least one dimension, typically the thickness dimension. Additionally, the nano-particle may be an organic or inorganic material either with or without surface modification. Conventional polymer foams tend to exhibit a cell mean size in the range between about 120 and 280 microns. By utilizing the nano-particle technology according to the present invention, it is possible to manufacture polymer foam structures having a cell mean size from several tens of microns to several hundred microns.
FIG. 3 is a scanning electron microscope (SEM) image of the foam including 1% nano-graphite in polystyrene foam. The average cell size of the foam without any other nucleating agent such as talc is around 220 microns; orientation in the x/z direction=1.26 (x 0.254, y 0.205, z 0.201 mm) FIG. 4 is an SEM image of the cell walls and struts of the foam product. The polystyrene foam contains 1% nano-graphite. The thickness of the cell walls is about 0.86 microns, the strut diameter is about 3.7 microns.
FIG. 5 illustrates the UV protectability of a polystyrene foam board including the nano-graphite of the present invention when the board is exposed to UV radiation. The test method used is a QUV test, followed by color measurement. Test methods and material standards for the QUV test include ISO 4982-1 Plastics, ASTM G-151, ASTM G-154, ASTM G53, British Standard BS 2782, Part 5, Method 540B, and SAE J2020, JIS D0205. All test methods and standards cited above are herein incorporated by reference in their entireties. The color measurements are made on the L*a*b scales. The L scale, from 0 to 100, represents a black to white relationship. The nano-graphite foam with grey color was almost no change from an extended UV exposure for more than 100 days. The a and b scale, from 1 to −1, represent the different color changes: from red to green, and from yellow to blue. Slight changing of color has been observed after more than 90 days UV exposure for the nano-graphite foam board.
A series of exemplary and comparative foam structures were prepared and evaluated to determine cell morphology, i.e., cell size, cell wall thickness (FIG. 6), effective diameter of cell strut (FIG. 7), cell anisotropy ratio, and certain other properties related to the foam cell morphology. In particular, FIGS. 6 and 7 show the SEM imagines of the cell wall and strut structure of a typical extruded polystyrene (XPS) foam. If a polymer foam is ideally depicted as a close wall of pentagonal dodecahedral cells in a uniform size, the cell wall thickness and the strut effective diameter then depend primarily on the density of the foam and the cell size.
The physical properties tested included one or more of density, compressive strength, thermal conductivity, aged thermal insulation value, thermal dimensional stability. In connection with these examples, cell size was measured according to ASTM D3576; density was measured according to ASTM D1622; thermal conductivity was measured according to ASTM C518; compressive strength was measured according to ASTM D1621; and thermal dimensional stability was measured according to ASTM D2126.
The foam structures were made with a twin co-rotated screw extruder comprising a pair of extruder screw, a heating zone mixer, a blowing agent injector, a cooler, a die and a shaper in accord with the operational conditions listed below in Table 1. The conditions set forth in Table 1 are applicable to Examples 1-6. Unless otherwise indicated, the polymer utilized in preparing the example foam compositions was an AtoFina granular polystyrene having a weight average molecular weight (Mw) of about 250,000, and melt index of about 3.1 μm per 10 minutes.
LMP Co-rotating Twin Leistritz MIC 27
Screw Extruder with GL/400 Co-rotating
Static Cooler Twin Screw Extruder
Die/Shaper Flat face die/ 20 × 2 mm
Shaper plate Flat Slot Die
Forming Atmosphere Atmosphere/Vacuum Atmosphere
Throughput - kg/hr. 100-200 6-10
Wt. % of HCFC-142b 10.5-11.5
Wt. % of HCFC-142b/22
Wt. % of CO2
Mixing 210-230 200-220
Temperature - ° C.
Extruder Pressure - 13000-17000 6900-8300
kPa (psi) (1950-2400) (1000-1200)
Die Melt 117-123 130-160
Die Pressure - 5400-6600 5500-8000
kPa (psi) (790-950) (800-1150)
Line Speed - m/hr 108-168 90-80
(ft/min) (5.9-9.2) (5-10)
Die Gap - mm 0.6-0.8 2
Vacuum - kPa 0-3.4 Atmosphere
(inch Hg) (0 to 16)
Polystyrene foams were prepared both with (7347) and without (7346) a 2.5% nano-particle loading using an LMP extruder. The nano-particle used to prepare this Example was an organoclay, specifically grade Nano-MMT 20A from Southern Clay Products Inc., that was melt compounded with a polystyrene polymer, specifically grade CX5197 from AtoFina, to form a melt polymer. The nano-particles exhibited an intercalated nano-MMT layer structure when examined using X-ray diffraction. The comparison sample did not include any nano-particles, but incorporated 0.8% talc loading as the nucleating agent. The comparison sample exhibited an average cell size of around 186 microns while the exemplary example utilizing the nano-particle foam exhibited a significantly reduced average cell size of around 60 microns. The exemplary example also exhibited a cell wall thickness of around 0.5 micron, and a strut effective diameter of around 5 microns. As reflected below in Table 2, the exemplary foam composition did not exhibit corrugation, was processed without undue process difficulty and provided improvements in compressive strength of around 30%.
Nano- Average Cell
Particle Cell Anisotropic Density Strength Thickness
Sample Wt. % micron Ratio* kg/m3 kPa mm
7346 0 186 0.949 29.28 286 37
7347 2.5 62 0.968 32 372 26
*Cell anisotropic ratio: K = z/(x.y.z)1/3 where, x, an average cell size in the longitudinal (extruding) direction, y, cell size in the transverse direction, and z, cell size in the board thickness direction
Sample foams (7349) were produced according to the process outlined in Example 1, but using 0.5% of an intercalated nano-MMT in a polystyrene composition to produce an exemplary foam having a density of about 26.5 kg/m3, a thickness of about 38 mm and a width of about 600 mm. The reduction in the amount of nano-MMT incorporated into the composition resulted in a slightly increased cell size, about 83 microns (FIG. 8), compared with Example 1, while maintaining improved strength, 329 kPa, over the comparative foam compositions.
Foams (7790) were prepared using a nano-particle loading of 2% nano-calcium carbonate from Ampacet, along with 1% talc as an additional nucleating agent and 1% of stabilized hexabromocyclododecone as fire retardant agent in a LMP extruder. The nano-calcium carbonate particles were typically elongated, having average dimensions of 80 nm×2 μm, and were provided in a 50% master batch composition in combination with an olefinic copolymer carrier resin. The rest of formulation was polystyrene: 80% Nova 1220 (Melt Index=1.45) and 16% Nova 3900 (Melt Index=34.5). The exemplary foam produced was 28 mm thick, 400 mm wide and had an average cell size of 230 microns with a cell orientation—the ratio of the cell dimension in the extrusion direction to the cell dimension in the thickness direction (x/z)—as high as 1.54 (see FIG. 9).
Foams (7789) were produced as in Example 3, but used 3.3% intercalated expanded nano-graphite from Superior Graphite Company as the nano-particles. The expanded nano-graphite included nano-sheets of graphite having thicknesses ranging from about 10 to about 100 nm and widths of around 3 p.m. The exemplary foam exhibited substantially the same thickness, width, and density (49 kg/m3) as Example 3, but had a smaller average cell size of 166 microns and cell orientation value of 1.21 (see FIG. 10). The thermal conductivity of this foam is as low as 0.14 K·m2/W for samples after being aged for 20 days.
Foams (7289, 7291) were prepared using a Leistritz extruder to produce samples having a thickness of around 10 mm, a width of around 50 mm, and a density of around 46 kg/m3. Both samples with 0.5% of talc as nucleating agent, and 10% of HCFCl42b/22 as blowing agent. Some characters of cell morphology are summarized as Table 3.
Nano- Average Cell Cell Wall Effective
Particle* Cell Orientation Cell Size Thickness Diameter
Sample Wt. % micron x/z x y z micron micron
7289 0 341 0.99 355 359 339 1.8 4.2
7291 5 174 0.95 165 183 173 0.8 5.1
Foams (7293, 7294) were prepared as in Example 5, but using 6 wt % of carbon dioxide as the blowing agent and 0.2 wt % of talc as a conventional nucleating agent. Some characteristics of the resulting cell morphologies (FIG. 11) are summarized below in Table 4.
7293 0 380 0.92 355 396 388 1.4 3
7294 5 146 0.76 146 121 158 0.3 5.4
In the following samples and control samples, rigid polystyrene foam boards are prepared by a twin screw LMP extruder with flat die and shaper plate; and a two single screw tandem extruder with radial die and slinky shaper. A vacuum may also be applied in both of the above described pilot and manufacturing lines.
Table 5 shows the process conditions for samples in a twin screw extruder for making foam boards having a width of 16 inches and a thickness of one inch.
Samples on Table 8
Wt. % of nano-graphite 1 to 5
Wt. % of talc 0.5-1.5
Wt. % of nano-carbon black 0 to 6
Wt. % of mica 0 to 4
Wt. % of HCFC-142b 11
Extruder Pressure, Kpa (psi) 13000-17000
(1950-2400)
Die Melt Temperature, (° C.) 117-123
Die Pressure, Kpa (psi) 5400-6600
(790-950)
Line Speed, m/hr (ft/min) 110-170
Throughput, kg/hr 100
Die Gap, mm 0.6-0.8
Vacuum KPa (inch Hg) 0-3.4
The thickness of nano-graphite used was confirmed by X-ray diffraction to be 29.7 nm, and 51 nm after compounding with about 60 wt % of polystyrene. Carbon black was not part of mix with nano-graphite due to its poor process ability and high smoke density during fire test.
The results of above examples are shown in Table 6. All R-values and compressive strength are tested after the samples aged for 180 days
Aged R-value Density Compressive Nano-
K · m2/K Kg/m3 Strength graphite
Run # (F · ft2 · hr/Btu) (pcf) psi Wt %
Control 0.029 27.68 NA 0
sample (5.05) (1.73)
696-2 0.025 28.64 21.55 1
X8234 (5.82) (1.79)
696-4 0.024 30.72 22.67 3
X8235 (6.03) (1.92)
692-2 0.025 27.84 25.69 1
X8207 (5.77) (1.74)
692-3 0.024 28.8 27.27 2
X8208 (5.94) (1.80)
692-4 0.024 28.96 26.87 3
X8209 (6.00) (1.81)
As shown from above samples, the addition of nano-graphite in foaming processing, preferably about 1% to about 3% by weight of the polymer has profound effect on the thermal resistance property. The range of the R-value was determined to be between about 5.7 and about 6.0 per inch.
Table 7 compares the operating conditions between batch foaming and traditional low-density foam extrusion.
Comparison of Operating Conditions
between Batch and Extrusion Foaming
Operating conditions Extrusion Batch Foaming
Temperature (° C.) 100~140 120
Pressure (psi) 1000~2000 2000
dP/dt (Pa/sec) 106 106
Prior to batch foaming, the polymerized nano-graphite/polystyrene compound is heated and compressed into a solid shape. The solid sheet is cut into small pieces according to the size of pressure vessel, such as 77×32×1 mm. The solid sheet specimen is then placed in a mold and foamed in a high-pressure vessel at about 80 to about 160° C., typically about 120° C. and about 500 to about 4000 psi, typically about 2000 psi. The solid sheet remains in the pressurized vessel for about 8 to about 50 hours, typically about 12 hours, after which the pressure in the vessel was released quickly (about 12 seconds) for foaming.
The nano-graphite/polystyrene foam of the batch foaming samples were evaluated to determine the amount infrared radiation transmitted through the foam. As infrared light is the major form of thermal radiation.
A piece of batch-foamed sample containing polystyrene and 3% graphite, and two other comparison samples containing polystyrene or polystyrene and 5% nano-clay were selected. On one side of the foam sample a light source of infrared laser was placed. On the other side of the sample, either a detector was placed to record the transmission light intensity or a temperature camera was placed to monitor the surface temperature change. The results are summarized in Table 8.
Infrared Light Transmission Through foam samples of polystyrene
(PS), polystyrene and 5% nano-clay (PS/5% clay), and polystyrene
and 3% nano-graphite (PS/3% graphite)
IR Transmission Emissive Received
Intensity (watts) Intensity Intensity % Trans
PS (control sample) 0.5 0.05 10%
PS/5% MHABS* 0.5 0.02 4%
PS/3% milled graphite worms 0.5 0.01 2%
*in-situ polymerized compound with 5% of reactive cationic surfactant, 2-methacryloyloxyethylhexadecyldimethyl ammonium bromide (MHAB) treated Na+ montmorillonite with 95% styrene monomer
As shown in Table 8, 10% of the light transmits through the pure PS foam sample, while only 4% through the PS/5% clay foam sample and only 2% through the PS/3% graphite sample. Both clay and graphite have the attenuation effect on the infrared light, however, as shown in the above table, PS/3% graphite has considerably better transmission attenuation.
The temperature of the PS/graphite sample, on the side of the sample opposite to the light source, was slightly elevated, having an increase of about 2-3° F. after 60 seconds of exposure (Table 9). There was no obvious change in surface temperature for foam samples of pure PS (control sample) and PS with MHABS nano-clay. As such, PS/graphite foam attenuates thermal radiation and enhances the heat solid conduction. Further, by improved graphite dispersion and concentration, these trends are expected to be more significant.
Temperature change for foam samples
of PS, PS/5% clay, and PS/3% graphite
on the surface opposite to the light source
IR Camera Temperature at Interval Time in Seconds
PS (control sample) 78.4° F. 78.4° F. 78.7° F. 78.8° F. 78.4° F. 78.5° F. 78.5° F.
PS/5% MHABS 79.2° F. 79.2° F. 79.5° F. 79.6° F. 79.4° F. 79.5° F. 79.6° F.
PS/3% milled graphite worms 80.6° F. 81.2° F. 81.7° F. 82° F. 82.6° F. 82.8° F. 83° F.
The invention of this application has been described above both generically and with regard to specific embodiments. Therefore, it is to be understood that a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure.
1. An extruded polymeric foam material comprising:
foam structures comprising:
a polymer comprising at least about 80% polystyrene, wherein said polymer has a molecular weight from about 30,000 to about 500,000;
from about 0.05 wt. % to about 5 wt. % nano-graphite having a size, in at least one dimension, of less than about 100 nanometers, wherein said nano-graphite provides a compressive strength that is about 30% greater than an otherwise identically extruded polymeric foam material containing no nano-graphite; and
at least one blowing agent,
wherein said foam structures comprise cell walls and struts that define cells having morphological parameters, wherein said morphological parameters include an elongated cell orientation, wherein a ratio of the cell dimension in an extrusion direction to the cell dimension in a thickness direction is either less than one or greater than 1 and up to 1.54; and
wherein the foam material is a rigid, closed cell, insulating foam board having an R-value per inch ranging from about 3 to about 8 and a median cell size of less than about 150 microns.
2. The polymeric foam material of claim 1, wherein said nano-graphite is an expanded nano-graphite.
3. The polymeric foam material of claim 2, wherein at least about 90% of said cells are closed cells.
4. The polymeric foam material of claim 1, wherein said cells have a mean cell size of about 60 microns.
5. The polymeric foam material of claim 1, wherein at least one blowing agent is selected from the group consisting of organic, inorganic and chemical blowing agents.
6. The polymeric foam material of claim 5, wherein at least one blowing agent is selected from the group consisting of: aliphatic hydrocarbons having 1-9 carbon atoms and fully or partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms.
7. A rigid foam insulation board comprising the polymeric material of claim 6, wherein the polymeric material is extruded into a rigid board.
8. The polymeric foam material of claim 5, wherein said blowing agent is selected from the group consisting of: 1-chloro-1,1-difluoroethane (HCFC-142b), HCFC-134a, carbon dioxide, blends of HCFC-142b with carbon dioxide, HCFC-134a with carbon dioxide, carbon dioxide with ethanol, or carbon dioxide with water.
9. The polymeric foam material of claim 5, wherein at least one blowing agent is selected from the group consisting of: difluoromethane (HFC-32), ethyl fluoride (HFC-161), 1,2-difluoroethane (HFC-142), 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC143a), 1,1,1,2-tetrafluoro-ethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), 2,2-difluoropropane (HFC-272fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1,1,3,3-pentafluoropropane (HFC 245fa), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,3,3-pentafluorobutane (HFC-365mfc), chlorodifluoromethane (HCFC22), 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 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), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), and mixtures thereof.
10. The polymeric foam material of claim 1, wherein at least one blowing agent is selected from 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), 1,2-difluoroethane (HFC-142) and mixtures thereof.
11. The polymeric foam material of claim 1, further comprising an additive selected from the group consisting of: flame retardants, mold release aids, pigments and fillers.
12. The polymeric foam material of claim 1, wherein said rigid, closed cell board is formed by extrusion.
13. The polymeric foam material of claim 1, wherein said rigid, closed cell board is an insulating foam board having a thickness from about ⅛ inch to about 12 inches.
14. A rigid foam insulation board comprising the polymeric material of claim 1, wherein the polymeric material is extruded into a rigid board.
15. The polymeric foam material of claim 1, wherein said foam structures further comprise one or more acrylate containing polymers, said one or more acrylate containing polymers being a copolymer copolymerized from a compound selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, acrylonitrile, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, and combinations thereof.
16. The polymeric foam material of claim 15, wherein the copolymer is a copolymer of methyl acrylate.
17. The polymeric foam material of claim 1, wherein said nano-graphite has a size, in at least two dimensions, of less than about 100 nanometers.
18. An extruded rigid foam insulation product comprising:
a polymeric material comprising:
nano-graphite; and
wherein the nano-graphite particles are selected from the group consisting of nanosheets of graphite, intercalated nano-graphite, exfoliated nano-graphite and expanded nano-graphite, and have a size, in at least one dimension, of less than about 100 nanometers;
wherein said polymeric material comprises cell walls and struts that define cells having morphological parameters, wherein said morphological parameters include an elongated cell orientation and a median cell size of less than about 150 microns, wherein a ratio of the cell dimension in an extrusion direction to the cell dimension in a thickness direction is either less than one or greater than 1 and up to 1.54;
wherein said nano-graphite is present in said polymeric material in an amount from about 0.05% to about 5% by weight based on said polystyrene,
wherein said nano-graphite provides a compressive strength that is about 30% greater than an otherwise identically extruded rigid foam insulation product containing no nano-graphite; and
wherein the extruded rigid foam insulation product has a density ranging from 28 to 31 kg/m3.
19. The rigid foam insulation product of claim 18, wherein at least one blowing agent is selected from the group consisting of: aliphatic hydrocarbons having 1-9 carbon atoms and fully or partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms.
20. The rigid foam insulation product of claim 19, wherein at least one blowing agent is selected from 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), 1,2-difluoroethane (HFC-142) and mixtures thereof.
21. The rigid foam insulation product of claim 18, wherein said insulation product is a board having a thickness from about ⅛ inch to about 12 inches.
22. The rigid foam insulation board of claim 21, further comprising one or more additives selected from infrared attenuating agents, plasticizers, flame retardant chemicals, elastomers, extrusion aids, antioxidants, pigments, fillers, antistatic agents and UV absorbers.
23. The rigid foam insulation product of claim 18, wherein said nano-graphite comprises nanosheets of graphite having a thickness between about 10 to about 100 nanometers.
24. The rigid foam insulation product of claim 18, wherein at least about 90% of which cells are closed cells.
25. The rigid foam insulation product of claim 18, wherein said foam structures comprise one or more acrylate containing polymers, wherein the one or more acrylate containing polymers is a copolymer copolymerized from a compound selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, acrylonitrile, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, and combinations thereof.
26. The rigid foam insulation product of claim 25, wherein the copolymer is a copolymer of methyl acrylate.
27. The polymeric foam material of claim 18, wherein said nano-graphite has a size, in at least two dimensions, of less than about 100 nanometers.
28. The extruded rigid foam insulation product of claim 18, wherein said product has an R-value per inch ranging from about 5 to about 6.0.
US12769144 2003-11-26 2010-04-28 Thermoplastic foams and method of forming them using nano-graphite Active US9359481B2 (en)
US10722929 US8568632B2 (en) 2003-11-26 2003-11-26 Method of forming thermoplastic foams using nano-particles to control cell morphology
US11026011 US7605188B2 (en) 2004-12-31 2004-12-31 Polymer foams containing multi-functional layered nano-graphite
US11481130 US20080287560A1 (en) 2004-12-31 2006-07-05 Polymer foams containing multi-functional layered nano-graphite
US12769144 US9359481B2 (en) 2003-11-26 2010-04-28 Thermoplastic foams and method of forming them using nano-graphite
US15147159 US20160319093A1 (en) 2003-11-26 2016-05-05 Thermoplastic foams and method of forming them using nano-graphite
US10722929 Continuation-In-Part US8568632B2 (en) 2003-11-26 2003-11-26 Method of forming thermoplastic foams using nano-particles to control cell morphology
US15147159 Division US20160319093A1 (en) 2003-11-26 2016-05-05 Thermoplastic foams and method of forming them using nano-graphite
US20110064938A1 true US20110064938A1 (en) 2011-03-17
US9359481B2 true US9359481B2 (en) 2016-06-07
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US12769144 Active US9359481B2 (en) 2003-11-26 2010-04-28 Thermoplastic foams and method of forming them using nano-graphite
US15147159 Pending US20160319093A1 (en) 2003-11-26 2016-05-05 Thermoplastic foams and method of forming them using nano-graphite
US (2) US9359481B2 (en)
CN102504324B (en) * 2011-10-13 2013-10-30 南京红宝丽股份有限公司 Physical foaming agent and rigid polyurethane foam plastic prepared by same
EP2589477B1 (en) 2011-11-03 2016-03-09 Kamal Mostafa Plastic foam sheet and method for processing of flat plastic foam sheets
DE102011119607A1 (en) 2011-11-29 2013-05-29 Kamal Mostafa Method for processing of planar plastic foam board, involves performing irreversible and reversible compressions of plastic foam board are performed such that compressed thickness of plastic foam board is less than initial thickness
KR20140023581A (en) * 2012-08-16 2014-02-27 (주)엘지하우시스 Thermosetting foaming body with superior adiabatic and flameproof effect and method for manufacturing the same
CN106459470A (en) 2014-05-30 2017-02-22 康涅狄格大学 Graphene/graphite polymer composite foam derived from emulsions stabilized by graphene/graphite kinetic trapping
KR20180013926A (en) * 2015-05-29 2018-02-07 오웬스 코닝 인텔렉츄얼 캐피탈 엘엘씨 Extruded polystyrene foam
CN105924714A (en) * 2016-05-17 2016-09-07 高永涛 Flexible low-temperature cryogenic thermal insulating material
US2365086A (en) 1943-09-21 1944-12-12 Joseph T Kamowski Thermal insulating jacket
US3627480A (en) 1968-08-15 1971-12-14 Ici Ltd Precipitated calcium carbonate
US3673290A (en) 1969-11-26 1972-06-27 Dow Chemical Co Foamed clay process
JPS63183941U (en) 1987-05-18 1988-11-28
EP0353701A2 (en) 1988-08-02 1990-02-07 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha An extruded synthetic resin foam and its manufacturing method
US4996109A (en) 1988-08-04 1991-02-26 Rohm Gmbh Hard foam cores for laminates
CN1057228A (en) 1990-06-14 1991-12-25 欧文斯-伊利诺塑料制品有限公司 Polystyrene foam sheet manufacture
US5234967A (en) 1991-02-18 1993-08-10 Sanyo Electric Co., Ltd. Rigid foamed polyurethane and process for the manufacture of the same
EP0620246A1 (en) 1993-04-13 1994-10-19 ALGOSTAT GmbH &amp; CO. KG Polystyrene hard foam moulded articles
US5550170A (en) 1993-09-25 1996-08-27 Huels Aktiengesellschaft Process for the production of foam beads
EP0729999A1 (en) 1995-03-03 1996-09-04 Tosoh Corporation Fire-retardant polymer composition
WO1997031053A1 (en) 1996-02-23 1997-08-28 The Dow Chemical Company Dispersions of delaminated particles in polymer foams
CN1170662A (en) 1996-04-04 1998-01-21 三井东压化学株式会社 Injection-expansion molded, thermoplastic resin product and production process thereof
WO1998003581A1 (en) 1996-07-24 1998-01-29 E.I. Du Pont De Nemours And Company Closed cell thermoplastic foams containing hfc-134
WO1998051734A1 (en) 1997-05-14 1998-11-19 Basf Aktiengesellschaft Method for producing expandable styrene polymers containing graphite particles
WO1999031170A1 (en) 1997-12-18 1999-06-24 The Dow Chemical Company Foams comprising hfc-134 and a low solubility co-blowing agent and a process for making
WO1999047592A1 (en) 1998-03-16 1999-09-23 The Dow Chemical Company Open-cell foam and method of making
US5977197A (en) 1996-02-02 1999-11-02 The Dow Chemical Company Compressed, extruded, evacuated open-cell polymer foams and evacuated insulation panels containing them
EP1024163A1 (en) 1998-04-23 2000-08-02 Kaneka Corporation Extruded styrene resin foam and process for producing the same
WO2000034363A3 (en) 1998-12-04 2000-09-21 Dow Chemical Co Soft and flexible foams
EP0675918B1 (en) 1992-12-22 2000-09-27 REEDY, Michael E. Process for producing alkenyl aromatic foams using a combination of atmospheric and organic gases and foams produced thereby
WO2001040362A1 (en) 1999-11-30 2001-06-07 Owens Corning Extruded foam product
EP0863175B1 (en) 1997-03-06 2001-09-05 Basf Aktiengesellschaft Foam plates with lowered heat conductivity
US20010036970A1 (en) 2000-03-17 2001-11-01 Park Chung P. Cellular acoustic absorption polymer foam having improved thermal insulating performance
US20020006976A1 (en) 2000-03-17 2002-01-17 Suresh Subramonian Preparation of a macrocellular acoustic foam
US6340713B1 (en) 1997-05-14 2002-01-22 Basf Aktiengesellschaft Expandable styrene polymers containing graphite particles
WO2001039954A3 (en) 1999-12-02 2002-01-24 Dow Chemical Co Hollow-strand foam and preparation thereof
US6350789B1 (en) 2000-08-17 2002-02-26 Owens Corning Fiberglas Technology, Inc. Extruded foam product with 134a and alcohol blowing agent
US20020041955A1 (en) 2000-09-29 2002-04-11 Takiron Co., Ltd. Fire-retardant antistatic vinyl chloride resin moldings
EP1205437A1 (en) 1999-05-27 2002-05-15 Eiji Osawa Method for preparing nano-size particulate graphite
JP2002212330A (en) 2000-11-28 2002-07-31 Atofina Chemicals Inc Nanoclay-containing polymer foam
US20020121717A1 (en) 1998-12-04 2002-09-05 Chaudhary Bharat I. Acoustical insulation foams
US6521672B1 (en) 1999-05-10 2003-02-18 Basf Aktiengesellschaft Open-cell particulate foams
US20030082343A1 (en) 2001-11-01 2003-05-01 Brucker Michel J. Bendable polymeric foam with a reinforced slit
EP0922554B1 (en) 1997-12-08 2003-06-25 Dow Deutschland Inc. Multilayer foams, method of production and use
JP2003292664A (en) 2002-04-08 2003-10-15 Jsp Corp Extrusion-foamed plate of polystyrene resin and manufacturing method therefor
JP2004196907A (en) 2002-12-17 2004-07-15 Jsp Corp Method for producing polystyrene-based resin extruded foam plate and polystyrene-based resin extruded foam plate
US20040167240A1 (en) 2002-05-09 2004-08-26 Sandrine Burgun Fire resistance acoustic foam
WO2004067577A3 (en) 2002-12-20 2004-12-16 Exxonmobil Chem Patents Inc Polymerization processes
JP2005002268A (en) 2003-06-13 2005-01-06 Jsp Corp Styrene resin foam comprising graphite powder
US6864298B2 (en) 2001-02-08 2005-03-08 Basf Aktiengesellschaft Expandable polyolefin particles
EP1214372B1 (en) 1999-09-03 2005-12-28 Dow Global Technologies Inc Insulating extruded foams having a monovinyl aromatic polymer with a broad molecular weight distribution
WO2006009980A3 (en) 2004-06-21 2006-02-23 Exxonmobil Chem Patents Inc Olefin polymerisation process
US20060148916A1 (en) 2004-12-31 2006-07-06 Loh Roland R Polymer foams containing multi-functional layered nano-graphite
US7160929B1 (en) 2002-02-13 2007-01-09 Wrigt Materials Research Co Nanocomposite and molecular-composite polymer foams and method for their production
JP2007512425T5 (en) 2008-01-17
US20080287560A1 (en) 2004-12-31 2008-11-20 Loh Roland R Polymer foams containing multi-functional layered nano-graphite
ES360077A1 (en) * 1967-11-18 1970-06-16 Consiglio Nazionale Ricerche Improvements in the electrodialysis process by treating the feedwater resinaspermutadoras ion.
GB0023488D0 (en) * 2000-09-25 2000-11-08 Unilever Plc Production of anionic surfactant granules by in situ neutralisation
EP0515125A1 (en) 1991-05-20 1992-11-25 E.I. Du Pont De Nemours And Company Foam blowing agent composition and process for producing foams
JPH11504359A (en) 1995-04-27 1999-04-20 ザ ダウ ケミカル カンパニー Microbubbles foams and methods of use thereof comprising an infrared attenuating agents
US6130265A (en) 1997-05-14 2000-10-10 Basf Aktiengesellschaft Method for producing expandable styrene polymers containing graphite particles
JP2002521543A (en) 1998-07-27 2002-07-16 ビーエーエスエフ アクチェンゲゼルシャフト Preparation of expandable styrene polymers containing graphite particles
KR20010071028A (en) 1998-07-27 2001-07-28 스타르크, 카르크 Method for producing expandable styrene polymers containing exfoliated graphite particles
US20030162852A1 (en) 1998-12-04 2003-08-28 Chaudhary Bharat I. Acoustical insulation foams
WO2000034365A3 (en) 1998-12-04 2000-09-14 Dow Chemical Co Closed cell alkenyl aromatic foam
US6133333A (en) 1998-12-04 2000-10-17 The Dow Chemical Company Soft and flexible foams made from blends of alkenyl aromatic polymers and alpha-olefin/vinyl or vinylidene aromatic and/or sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene interpolymers
US20020155270A1 (en) 1998-12-04 2002-10-24 Chaudhary Bharat I. Enlarged cell size foams made from blends of alkenyl aromatic polymers and alpha-olefin/vinyl or vinylidene aromatic and/or sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene interpolymers
EP1209189B1 (en) 2000-11-28 2005-06-29 Arkema Inc. Foam polymer/clay nanocomposites
WO2004065461A3 (en) 2002-05-02 2004-12-16 Univ Ohio State Res Found Nano-sized particles such as nano-clays can be mixed with polymers through either melt compounding or in-situ polymerization
WO2004003063A8 (en) 2002-07-03 2004-07-22 Fagerdala Deutschland Gmbh Thermoplastic foamed materials comprising nanostructured filling materials and method for producing the same
WO2005054349A1 (en) 2003-11-26 2005-06-16 Owens Corning Method of forming thermoplastic foams using nano-particles to control cell morphology
WO2006073712A1 (en) 2004-12-31 2006-07-13 Owens Corning Intellectual Capital, Llc. Polymer foams containing multi-functional layered nano-graphite
Advisory Action from U.S. Appl. No. 10/722,929 dated Aug. 2, 2011.
Advisory action from U.S. Appl. No. 10/722,929 dated Jan. 29, 2009.
Advisory action from U.S. Appl. No. 10/722,929 dated Mar. 16, 2007.
Advisory action from U.S. Appl. No. 10/722,929 dated Nov. 19, 2009.
Advisory Action from U.S. Appl. No. 10/722,939 dated Mar. 18, 2011.
Cassegneau, et al, Preparation and Characterization of Ultrathin Films Layer-by-Layer Self Assemgbgled from Graphite Oxide Nanoplatelets and Polymer, Langmuir, 2000, 16, 7318-24.
Chen et al., "Dispersion of Graphite Nanosheets in a Polymer Matrix and the Conducting Property of the Nanocomposites", Polymer Engineering and Science, Dec. 2001, vol. 41, No. 12, pp. 2148-2154.
Chen et al., "Preparation of polymer/graphite conducting nanocomposite by intercalation polymerization", J of Applied Polymer Science, 82, 2506-2513 (2001).
Communication from European Application No. 04811960.6 dated Jun. 15, 2011.
Communication from European Application No. 06800020.7 dated May 17, 2010.
Drzal et al., "Graphite nanoplatelets as reinforcements for polymers", Polymers Preprints (American Chemical Society, Division of Polymer Chemistry), 42 (2), 42-43 (2001).
Examiner's Answer from U.S. Appl. No. 10/722,929 dated Aug. 4, 2009.
Han et al., "Extrusion of Polystyrene Foams Reinforced with Nano-Clays", 2003 ANTEC Conference, pp. 1635-1639.
International Search Report from PCT/US04/39336 dated Apr. 7, 2005.
International Search Report from PCT/US05/45291 dated May 12, 2006.
International Search Report from PCT/US06/035056 dated Feb. 20, 2008.
International Search Report from PCT/US06/26490 dated Aug. 16, 2007.
International Search Report from PCT/US08/58643 dated Jul. 23, 2008.
Mantell, C.L. "Carbon and Graphite Handbook", (1968), Cover pages and Table of Contents, Interscience Publishers copyright John Wiley & Sons, Inc., printed U.S. 11 pgs.
Modesti et al., "Expandable graphite as an intumescent flame retardant in polyisocyanurate-polyurethane forms", Polymer Degradation and Stability, 77, 195-202 (2002).
Notice of Abandonment from U.S. Appl. No. 11/481,130 dated Jul. 12, 2010.
Notice of Allowance from U.S. Appl. No. 10/722,929 dated Jan. 6, 2010.
Notice of Allowance from U.S. Appl. No. 10/722,929 dated Jul. 10, 2013.
Notice of Allowance from U.S. Appl. No. 11/026,011 dated Aug. 3, 2009.
Office action from Australian Application No. 2004295331 dated Aug. 4, 2009.
Office action from Australian Application No. 2005323239 dated Jul. 26, 2010.
Office action from Australian Application No. 2005323239 dated Sep. 5, 2011.
Office action from Canadian Application No. 2,545,007 dated Apr. 30, 2012.
Office action from Canadian Application No. 2,545,007 dated Jan. 22, 2013.
Office action from Canadian Application No. 2,545,007 dated Jun. 23, 2011.
Office action from Canadian Application No. 2,592,281 dated Jun. 27, 2012.
Office action from Chinese Application No. 200480035089.x dated Aug. 15, 2008.
Office action from Chinese Application No. 200480035089.x dated Jun. 5, 2009.
Office action from Chinese Application No. 200480035089.x dated Nov. 28, 2008.
Office action from Chinese Application No. 200480035089.x dated Sep. 7, 2007.
Office action from Chinese Application No. 200580046678.2 dated Apr. 6, 2011.
Office action from Chinese Application No. 200580046678.2 dated Dec. 11, 2009.
Office action from Chinese Application No. 200580046678.2 dated Jul. 6, 2011.
Office action from Chinese Application No. 200580046678.2 dated Oct. 14, 2011.
Office action from Indian Application No. 1139/KOLNP/2006 dated Nov. 26, 2009.
Office action from Indian Application No. 1139/KOLNP/2006 dated Nov. 28, 2008.
Office action from Japanese Application No. 2006-541658 dated Mar. 22, 2011.
Office action from Japanese Application No. 2007-549422 dated Oct. 11, 2011.
Office action from Japanese Application No. 2007-549422 dated Sep. 11, 2011.
Office action from Korean Application No. 2006-7009466 dated May 6, 2011.
Office action from Korean Application No. 2007-7017520 dated Jun. 22, 2012.
Office action from Mexican Application No. 06/05995 dated Feb. 4, 2010.
Office action from Mexican Application No. 06/05995 dated Oct. 19, 2009.
Office action from Mexican Application No. 07/07970 dated Jun. 14, 2010.
Office action from New Zealand Application No. 547,067 dated Nov. 3, 2008.
Office action from U.S. Appl. No. 10/722,929 dated Apr. 6, 2012.
Office action from U.S. Appl. No. 10/722,929 dated Aug. 13, 2012.
Office action from U.S. Appl. No. 10/722,929 dated Aug. 26, 2011.
Office action from U.S. Appl. No. 10/722,929 dated Dec. 26, 2007.
Office action from U.S. Appl. No. 10/722,929 dated Jan. 25, 2006.
Office action from U.S. Appl. No. 10/722,929 dated Jul. 25, 2005.
Office action from U.S. Appl. No. 10/722,929 dated Jul. 3, 2007.
Office action from U.S. Appl. No. 10/722,929 dated Jun. 12, 2008.
Office action from U.S. Appl. No. 10/722,929 dated Jun. 8, 2006.
Office action from U.S. Appl. No. 10/722,929 dated Mar. 26, 2008.
Office action from U.S. Appl. No. 10/722,929 dated May 17, 2010.
Office action from U.S. Appl. No. 10/722,929 dated May 17, 2013.
Office action from U.S. Appl. No. 10/722,929 dated May 24, 2011.
Office action from U.S. Appl. No. 10/722,929 dated Nov. 20, 2008.
Office action from U.S. Appl. No. 10/722,929 dated Nov. 30, 2006.
Office action from U.S. Appl. No. 10/722,929 dated Nov. 4, 2010.
Office action from U.S. Appl. No. 10/722,929 dated Oct. 22, 2012.
Office action from U.S. Appl. No. 11/026,011 dated Feb. 4, 2009.
Office action from U.S. Appl. No. 11/026,011 dated Jul. 31, 2008.
Office action from U.S. Appl. No. 11/026,011 dated May 17, 2007.
Office action from U.S. Appl. No. 11/026,011 dated May 8, 2009.
Office action from U.S. Appl. No. 11/481,130 dated Dec. 3, 2009.
Pan et al., "A new process of fabricating electrically conducting nylon 6/graphite nanocomposites via intercalation polymerization", J. of Polymer Science, Part B, Polymer Physics, 38, pp. 1626-1633 (2000).
Panel Decision from U.S. Appl. No. 10/722,929 dated Mar. 12, 2009.
Panel Decision from U.S. Appl. No. 10/722,929 dated Mar. 27, 2009.
Uhl et al, "Polystyrene/graphite nanocomposites: effect on thermal stability", Polymer Degradation and Stability, 76, 111-122 (2002).
Xiao et al., "Preparation of exfoliated graphite/polystyrene compsite by polymerizatiojn-filling technique", Polymer, 42, 4813-4816 (2001).
Zabel et al. "Graphite Intercalation Compounds I: Structure and Dynamics" (1990), Cover Pages and Table of Contents, copyright Springer-Verlag Berlin Heidelberg, printed in Germany, 13 pgs.
Zeng et al. "Polymer/Clay Nanocomposite Foams Prepared by CO2", 2003 ANTEC Conference, pp. 1732-1736.
Zhang et al. "Preparation and Combusion Properties of Flame Retardant SBA Cop9olymer/Graphite Oxide Nanocomposites", Marcromol, Mater Eng., Mar. 2004, 289, 355-59.
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