USOO7658797B2
`
`(12) United States Patent
`Guevara et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7.658,797 B2
`*Feb. 9, 2010
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`LIGHTWEIGHT CONCRETE
`COMPOSITIONS
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`(56)
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`References Cited
`
`U.S. PATENT DOCUMENTS
`
`Inventors: Tricia Guevara, Koppel, PA (US);
`Michael T. Williams, Beaver Falls, PA
`(US); Rick Hughes, Beaver, PA (US);
`Michael R. Kelley, Butler, PA (US);
`John K. Madish, Negley, OH (US);
`Kristen Van Buskirk, Aliquippa, PA
`(US)
`Assignee: NOVA Chemicals Inc., Moon Township,
`PA (US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 567 days.
`This patent is Subject to a terminal dis
`claimer.
`
`Notice:
`
`Appl. No.: 11/586,120
`
`Filed:
`
`Oct. 25, 2006
`
`Prior Publication Data
`US 2007/00624 15 A1
`Mar. 22, 2007
`
`Related U.S. Application Data
`Continuation-in-part of application No. 1 1/387,198,
`filed on Mar. 22, 2006.
`Provisional application No. 60/664,230, filed on Mar.
`22, 2005, provisional application No. 60/686,858,
`filed on Jun. 2, 2005.
`
`Int. C.
`(2006.01)
`C04B I6/08
`U.S. Cl. ........................ 106/724; 106/737: 106/823
`Field of Classification Search ................. 106/724,
`106/737, 823
`See application file for complete search history.
`
`
`
`3,021,291 A *
`3,023,175 A
`3,214,393 A
`3,257,338 A *
`3,272,765 A *
`3,547.412 A
`
`2, 1962
`2, 1962
`10, 1965
`6, 1966
`9, 1966
`12, 1970
`
`Thiessen ...................... 521,56
`Rodman, Jr.
`Sefton
`Sefton ......................... 521,54
`Sefton ......................... 521,54
`Klages et al
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`O 652 188
`
`5, 1995
`
`(Continued)
`OTHER PUBLICATIONS
`
`DE 19831295 (Koetze) Jan. 20, 2000 abstract.*
`(Continued)
`Primary Examiner Paul Marcantoni
`(74) Attorney, Agent, or Firm Gary F. Matz
`
`(57)
`
`ABSTRACT
`
`A lightweight ready-mix concrete composition that contains
`8-20 volume percent cement, 11-50 volume percent sand,
`10-31 volume percent prepuff particles, 9-40 volume percent
`coarse aggregate, and 10-22 volume percent water, where the
`Sum of components used does not exceed 100 Volume per
`cent. The prepuff particles have an average particle diameter
`of from 0.2 mm to 8 mm, a bulk density of from 0.02 g/cc to
`0.64 g/cc, an aspect ratio of from 1 to 3. The slump value of
`the composition measured according to ASTMC 143 is from
`2 to 8 inches. After the lightweight ready-mix concrete com
`position is set for 28 days, it has a compressive strength of at
`least 1400 psi as tested according to ASTM C39.
`
`14 Claims, 3 Drawing Sheets
`
`Metromont Ex-1017, p.1
`
`

`

`US 7.658,797 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`WO
`
`WOO1,66485
`
`9, 2001
`
`3, 1975 Bowles et all
`3,869,295 A
`5, 1977 Grofetal.
`4,026,723 A
`4,040,855 A * 8/1977 Rady-Pentek et al. ......... 521 55
`4,098,877 A
`7, 1978 Ball et al.
`4,265,964 A
`5, 1981 Burkhart
`4,298.394 A 11/1981 Leeming et al.
`4,303,756 A 12/1981 Kajimura et al.
`4,303,757 A 12/1981 Kajimura et al.
`4,398,958 A * 8/1983 Hodson et al. .............. 521,146
`4,412.961 A 11, 1983 DiBiasi etal
`I k 4
`f
`1
`4,518,550 A
`5, 1985 Miettinen et al.
`4,725,632 A
`2, 1988 Vess
`5,069,907 A 12/1991 Mixon et al.
`5,211,751 A
`5, 1993 Arfaei et al.
`5,238,749 A
`8, 1993 Cueman et al.
`5,288.480 A
`2f1994 Gaffar et al.
`5,472.498 A * 12/1995 Stephenson et al. ......... 106,672
`5,482,550 A
`1, 1996 Strait ......................... 106,677
`RE35,194 E
`4, 1996 Gerber
`5,580,378 A * 12/1996 Shulman ..................... 106,677
`5,586,643 A 12/1996 Zabron et al.
`5,622,556 A * 4, 1997 Shulman ..................... 106/677
`5,643,510 A
`7, 1997 Sucech
`5,725,652 A * 3, 1998 Shulman ..................... 106677
`5s 53634 A 12/1998 Ontkean
`w - -
`5,913,791 A
`6, 1999 Baldwin
`6,030,446 A
`2/2000 Doty et al.
`6,033,731 A
`3, 2000 Liebert et al.
`f
`ieb
`1
`6,080,796 A
`6, 2000 Liebert et al.
`6,127,439 A 10, 2000 Berghmans et al.
`6, 160,027 A 12/2000 Crevecoeur et al.
`6,242.540 B1
`6, 2001 Crevecoeur et al.
`6,800,129 B2 10/2004 Jardine et al.
`6,833,188 B2 12/2004 Semmens
`6,851,235 B2
`2/2005 Baldwin
`6,875,266 B1 * 4/2005 Naji et al. ................... 106,724
`6,908,949 B2
`6, 2005 Arch et al.
`6969,423 B2 11/2005 Lietal
`- W -
`1
`38 17769 A1
`S. Arch et al.
`2004, OO65,034 A1
`4/2004 Messenger et al.
`2004/0231916 A1 1 1/2004 Englert et al.
`2006/0217464 A1
`9, 2006 Guevara et al.
`2006/0225618 A1 10, 2006 Guevara et al.
`2007.0062415 A1
`3/2007 Guevara et al.
`
`FOREIGN PATENT DOCUMENTS
`
`FR
`JP
`WO
`WO
`WO
`
`2539 410 A1
`90,71449
`WO98,02397
`WOOO?O2826
`WOOOf 61519
`
`T 1984
`3, 1997
`1, 1998
`1, 2000
`10, 2000
`
`OTHER PUBLICATIONS
`Dipl.-Ing. Thorsten et al., High Strength Lightweight-Aggregate
`Concrete; 2nd Int. PhD Symposium in Civil Engineering, 1998
`Budapest. pp. 1-8.
`The Use of Styrocell B Beads in Cellular Bricks, Plaster and Light
`weight Concrete; Shell Chemicals Europe, Styrocell Bulletin, STY
`1.4. Issued Mar. 1998, 1st Edition, pp. 1-8.
`Sabaa, B.A., and Sri Ravindrarajah, R., "Controlling freeze and thaw
`durability of structural grade concrete with recycled expanded aggre
`s
`gate, Proceedings of the Second International Symposium on Struc
`tural Lightweight Aggregate Concrete, Jun. 18-22, 2000,
`Kristiansand, Norway, pp. 709-718.
`Sri Ravindrarajah, R. And Tuck, A.J., “Properties of polystyrene
`aggregate concrete'. Proc. of the 13th Australasian Conf. on the
`Mechanics of Structures & Materials, Jul. 5-6, 1993, Wollongong,
`Australia, pp. 705-712.
`Sri Ravindrarajah, R. And Tuck, A.J., “Properties of Hardened Con
`crete Containing Treated expanded Polystyrene Beads'. Int. J. Of
`Cement Composites, V 16, Dec. 1994, pp. 273-277.
`Sri Ravindrarajah, R. and Sivapathasundaram, P., “Properties of
`Polystyrene Aggregate Concrete Having the Densities of 1300 and
`1900 kg/m3', Journal of the Australian Ceramic Society, 1998, pp.
`217-222.
`Sri Ravindrarajah, R., “Bearing Strength of Concrete Containing
`Polystyrene Aggregate". Proceedings of the 8th RILEM Conference
`on the Durability of Building Materials & Components, Vancouver,
`Canada, 1999, pp. 505-514.
`Sabaa, B.A., and Sri Ravindrarajah, R., “Investigation of Pull-Out
`Strength Between Polystyrene Aggregate Concrete and Reinforcing
`s
`Steel”. Proceedings of the Second International Symposium on
`Structural Lightweight Aggregate Concrete, Jun. 18-22, 2000,
`Kristiansand, Norway, pp. 729-736.
`Sabaa, B.A., and Sri Ravindrarajah, R., “Impact Resistance of Poly
`styrene Aggregate Concrete With and Without Polypropylene
`Fibres.” Proceedings of the Second International Symposium on
`Structural Lightweight Aggregate Concrete, Jun. 18-22, 2000,
`Kristiansand, Norway, pp. 719-728.
`Naji. B., Sri Ravindrarajah, R. and Chung, H.W., "Flexural
`Behaviour of Ferrocement-Polystyrene Aggregate Concrete Com
`posites.” Proc. of the First Australasian Congress on Applied
`Mechanics, Feb. 21-23, 1996, Melbourne, Australia, pp. 351-356.
`Naji. B. Sri Ravindrarajah, R. and Chung, H.W. “Impact-Echo
`Response in Ferrocement-Polystyrene Beaded Concrete Laminates'.
`Proc. of the Int. Symp. On Non-Destructive testing in Civil Engineer
`ing, Sep. 26-28, 1995, Berlin, Germany, pp. 503-511.
`Sri Ravindrarajah, R. and Sivakumar, R., “Effect of Polystyrene
`Particle Shape on the Properties of Lightweight Aggregate Con
`crete'. Proceedings of the South African Conference on Polymers in
`Concrete, Jul. 2000, Kruger National Park, South Africa, pp. 195
`203.
`Sabaa, B. A., and Sri Ravindrarajah, R., “Compressive and Tensile
`Strength of “Adjusted Density” Concrete. Using Expanded Polysty
`rene Aggregate'. Proceedings of the South African Conference on
`Polymers in Concrete, Jul. 2000, Kruger National Park, South Africa,
`pp. 133-141.
`* cited by examiner
`
`Metromont Ex-1017, p.2
`
`

`

`U.S. Patent
`
`Feb. 9, 2010
`
`Sheet 1 of 3
`
`US 7.658,797 B2
`
`
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`s
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`Metromont Ex-1017, p.3
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`

`

`U.S. Patent
`
`Feb. 9, 2010
`
`Sheet 2 of 3
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`US 7.658,797 B2
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`
`
`Metromont Ex-1017, p.4
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`

`

`U.S. Patent
`
`Feb. 9, 2010
`
`Sheet 3 of 3
`
`US 7.658,797 B2
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`
`
`Metromont Ex-1017, p.5
`
`

`

`US 7,658,797 B2
`
`1.
`LIGHTWEIGHT CONCRETE
`COMPOSITIONS
`
`REFERENCE TO RELATED APPLICATION
`
`This application is a Continuation-In-Part of application
`Ser. No. 1 1/387,198 filed Mar. 22, 2006 entitled “Lightweight
`Concrete Compositions', which claims the benefit of priority
`of U.S. Provisional Application Ser. Nos. 60/664.230 filed
`Mar. 22, 2005 entitled “Light Weight Concrete Composite
`Using EPS Beads” and 60/686,858 filed Jun. 2, 2005 entitled
`“Lightweight Compositions and Materials.” which are both
`herein incorporated by reference in their entirety.
`
`BACKGROUND OF THE INVENTION
`
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`1. Field of the Invention
`The present invention is directed to novel compositions,
`materials, methods of their use and methods of their manu
`facture that are generally useful as agents in the construction
`and building trades. More specifically, the compounds of the
`present invention can be used in construction and building
`applications that benefit from a relatively lightweight,
`extendable, moldable, pourable, material that has high
`strength and often improved insulation properties.
`2. Description of the Prior Art
`In the field of preparation and use of lightweight cementi
`tious materials, such as so-called lightweight concrete, the
`materials that have been available to the trades up until now
`have generally required the addition of various constituents to
`achieve a strong but lightweight concrete mass that has a high
`homogeneity of constituents and which is uniformly bonded
`throughout the mass.
`U.S. Pat. Nos. 3,214,393, 3,257,338 and 3,272,765 dis
`close concrete mixtures that contain cement, a primary aggre
`35
`gate, particulate expanded styrene polymer, and a homog
`enizing and/or a Surface-active additive.
`U.S. Pat. No. 3,021.291 discloses a method of making
`cellular concrete by incorporating into the concrete mixture,
`prior to casting the mixture, a polymeric material that will
`expand under the influence of heat during curing. The shape
`and size of the polymeric particles is not critical.
`U.S. Pat. No. 5,580.378 discloses a lightweight cementi
`tious product made up of an aqueous cementitious mixture
`that can include fly ash, Portland cement, sand, lime and, as a
`weight saving component, micronized polystyrene particles
`having particle sizes in the range of 50 to 2000 um and a
`density of about 1 lb/ft. The mixture can be poured into
`molded products Such as foundation walls, roof tiles, bricks
`and the like. The product can also be used as a mason's
`mortar, a plaster, a stucco or a texture.
`JP9071 449 discloses a lightweight concrete that includes
`Portland cement and a lightweight aggregate such as foamed
`polystyrene, perlite or Vermiculite as a part or all parts of the
`aggregate. The foamed polystyrene has a granule diameter of
`0.1-10 mm and a specific gravity of 0.01-0.08.
`U.S. Pat. Nos. 5,580,378, 5,622,556, and 5,725,652 dis
`close lightweight cementitious products made up of an aque
`ous cementitious mixture that includes cement and expanded
`shale, clay, slate, fly ash, and/or lime, and a weight saving
`component, which is micronized polystyrene particles having
`particle sizes in the range of 50 to 2000 um, and characterized
`by having water contents in the range of from about 0.5% to
`50% VfV.
`U.S. Pat. No. 4,265,964 discloses lightweight composi
`tions for structural units such as wallboard panels and the like,
`which contain low density expandable thermoplastic gran
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`ules; a cementitious base material. Such as, gypsum, a Surfac
`tant; an additive which acts as a frothing agent to incorporate
`an appropriate amount of air into the mixture; a film forming
`component; and a starch. The expandable thermoplastic gran
`ules are expanded as fully as possible.
`WO 98 02397 discloses lightweight-concrete roofing tiles
`made by molding a hydraulic binder composition containing
`synthetic resin foams as the aggregate and having a specific
`gravity of about 1.6 to 2.
`WO 00/61519 discloses a lightweight concrete that
`includes a blend of from around 40% to 99% of organic
`polymeric material and from 1% to around 60% of an air
`entraining agent. The blend is used for preparing lightweight
`concrete that uses polystyrene aggregate. The blend is
`required to disperse the polystyrene aggregate and to improve
`the bond between the polystyrene aggregate and Surrounding
`cementitious binder.
`WO 01/66485 discloses a lightweight cementitious mix
`ture containing by volume: 5 to 80% cement, 10 to 65%
`expanded polystyrene particles; 10 to 90% expanded mineral
`particles; and water Sufficient to make a paste with a substan
`tially even distribution of expanded polystyrene after proper
`mixing.
`U.S. Pat. No. 6,851,235 discloses a building block that
`includes a mixture of water, cement, and expanded polysty
`rene (EPS) foam beads that have a diameter from 3.18 mm (/8
`inch) to 9.53 mm (3/8 inch) in the proportions of from 68 to 95
`liters (18 to 25 gallons) water; from 150 to 190kg (325 to 425
`1b) cement; and from 850 to 1400 liters (30 to 50 cubic feet)
`Prepuffbeads.
`U.S. Pat. No. 5,913,791 discloses a building block that has
`a cement-based attachment layer on one or both exterior
`Surfaces of the block that receives and holds a penetrating
`fastener Such as a nail, Screw, Staple, or the like. One cement
`based layer contains water, cement, and expanded polysty
`rene foam beads in first proportions and a second exterior
`Surface contains water, cement, and expanded polystyrene
`foam beads in second proportions different than the first
`proportions.
`Generally, the prior art recognizes the utility of using
`expanded polymers, in Some form, in concrete compositions,
`to reduce the overall weight of the compositions. The
`expanded polymers are primarily added to take up space and
`create voids in the concrete and the amount of “air space' in
`the expanded polymer is typically maximized to achieve this
`objective. Generally, the prior art assumes that expanded
`polymer particles will lower the strength and/or structural
`integrity of lightweight concrete compositions. Further, con
`crete articles made from prior art lightweight concrete com
`positions have at best inconsistent physical properties, such
`as Young's modulus, thermal conductivity, and compressive
`strength, and typically demonstrate less than desirable physi
`cal properties.
`Therefore, there is a need in the art for lightweight concrete
`compositions that provide lightweight concrete articles hav
`ing predictable and desirable physical properties that over
`come the above-described problems.
`
`SUMMARY OF THE INVENTION
`
`The present invention provides a lightweight ready-mix
`concrete composition that contains 8-20 Volume percent
`cement, 11-50 volume percent sand, 10-31 volume percent
`prepuff particles, 9-40 volume percent coarse aggregate, and
`10-22 volume percent water, where the sum of components
`used does not exceed 100 volume percent. The prepuff par
`ticles have an average particle diameter of from 0.2 mm to 8
`
`Metromont Ex-1017, p.6
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`

`US 7,658,797 B2
`
`3
`mm, a bulk density of from 0.02 g/cc to 0.64 g/cc, an aspect
`ratio of from 1 to 3. The slump value of the composition
`measured according to ASTM C 143 is from 2 to 8 inches.
`After the lightweight ready-mix concrete composition is set
`for 28 days, it has a compressive strength of at least 1400 psi
`as tested according to ASTM C39.
`
`DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a scanning electron micrograph of the Surface of
`a prepuffbead used in the invention;
`FIG. 2 is a scanning electron micrograph of the interior of
`a prepuffbead used in the invention;
`FIG. 3 is a scanning electron micrograph of the Surface of
`a prepuffbead used in the invention;
`FIG. 4 is a scanning electron micrograph of the interior of
`a prepuffbead used in the invention;
`FIG. 5 is a scanning electron micrograph of the Surface of
`a prepuffbead used in the invention; and
`FIG. 6 is a scanning electron micrograph of the interior of
`a prepuffbead used in the invention.
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`DETAILED DESCRIPTION OF THE INVENTION
`
`4
`ing a hydration reaction in the presence of a Sufficient quan
`tity of water to produce a final hardened product.
`As used herein, the term "cementitious mixture” refers to a
`composition that includes a cement material, and one or more
`fillers, adjuvants, or other aggregates and/or materials known
`in the art that form a slurry that hardens upon curing. Cement
`materials include, but are not limited to, hydraulic cement,
`gypsum, gypsum compositions, lime and the like and may or
`may not include water. Adjuvants and fillers include, but are
`not limited to sand, clay, fly ash, aggregate, air entrainment
`agents, colorants, water reducers/Superplasticizers, and the
`like.
`As used herein, the term “concrete” refers to a hard strong
`building material made by mixing a cementitious mixture
`with sufficient water to cause the cementitious mixture to set
`and bind the entire mass.
`As used herein, the term “ready mix' refers to concrete that
`is batched for delivery from a central plant instead of being
`mixed on a job site. Typically, a batch of ready mix is tailor
`made according to the specifics of a particular construction
`project and delivered in a plastic condition, usually in cylin
`drical trucks often referred to as “cement mixers.”
`As used herein, all Volume and weight percentages antici
`pate the use of a certain volume or weight of water. The
`particular amounts when referring to a dry-mix or ready-mix
`composition would be in the same proportions anticipating
`that the commensurate amount of water will be added to the
`dry-mix or ready-mix when it is to be finally formulated,
`mixed and otherwise readied for use.
`All compositional ranges expressed herein are limited in
`total to and do not exceed 100 percent (volume percent or
`weight percent) in practice. Where multiple components can
`be present in a composition, the Sum of the maximum
`amounts of each component can exceed 100 percent, with the
`understanding that, and as those skilled in the art readily
`understand, that the amounts of the components actually used
`will conform to the maximum of 100 percent.
`As used herein, the terms “(meth)acrylic' and “(meth)
`acrylate” are meant to include both acrylic and methacrylic
`acid derivatives. Such as the corresponding alkyl esters often
`referred to as acrylates and (meth)acrylates, which the term
`"(meth)acrylate is meant to encompass.
`As used herein, the term “polymer is meant to encompass,
`without limitation, homopolymers, copolymers, graft
`copolymers, and blends and combinations thereof.
`In its broadest context, the present invention provides a
`method of controlling air entrainment in a formed article. The
`formed article can be made from any formable material,
`where particles containing Void spaces are used to entrain air
`in a structurally Supportive manner. Any suitable formable
`material can be used, so long as the particles containing Void
`spaces are not damaged during the forming process.
`As used herein, the term “composite material refers to a
`Solid material which includes two or more Substances having
`different physical characteristics and in which each Substance
`retains its identity while contributing desirable properties to
`the whole. As a non-limiting example, composite materials
`can include concrete within which prepuff beads are uni
`formly dispersed and embedded.
`Thus, the present invention is directed to methods of con
`trolling air entrainment where an article is formed by com
`bining a formable material and particles containing Void
`spaces to provide a mixture and placing the mixture in a form.
`Although the application discloses in detail cementitious
`mixtures with polymer particles, the concepts and embodi
`ments described herein can be applied by those skilled in the
`art to the other applications described above.
`
`Other than in the operating examples or where otherwise
`indicated, all numbers or expressions referring to quantities
`of ingredients, reaction conditions, etc. used in the specifica
`tion and claims are to be understood as modified in all
`instances by the term “about.” Accordingly, unless indicated
`to the contrary, the numerical parameters set forth in the
`following specification and attached claims are approxima
`tions that can vary depending upon the desired properties,
`which the present invention desires to obtain. At the very
`least, and not as an attempt to limit the application of the
`doctrine of equivalents to the scope of the claims, each
`numerical parameter should at least be construed in light of
`the number of reported significant digits and by applying
`ordinary rounding techniques.
`Notwithstanding that the numerical ranges and parameters
`setting forth the broad scope of the invention are approxima
`tions, the numerical values set forth in the specific examples
`are reported as precisely as possible. Any numerical values,
`however, inherently contain certain errors necessarily result
`ing from the standard deviation found in their respective
`testing measurements.
`Also, it should be understood that any numerical range
`recited herein is intended to include all Sub-ranges Subsumed
`therein. For example, a range of “1 to 10” is intended to
`include all Sub-ranges between and including the recited
`minimum value of 1 and the recited maximum value of 10;
`that is, having a minimum value equal to or greater than 1 and
`a maximum value of equal to or less than 10. Because the
`disclosed numerical ranges are continuous, they include
`every value between the minimum and maximum values.
`Unless expressly indicated otherwise, the various numerical
`ranges specified in this application are approximations.
`As used herein, the term "particles containing Void spaces'
`refer to expanded polymer particles, prepuff particles, and
`other particles that include cellular and/or honeycomb-type
`chambers at least Some of which are completely enclosed,
`that contain air or a specific gas or combination of gasses, as
`a non-limiting example prepuff particles as described herein.
`As used herein the terms “cement” and "cementitious’
`refer to materials that bond a concrete or other monolithic
`product, not the final product itself. In particular, hydraulic
`cement refers to a material that sets and hardens by undergo
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`Metromont Ex-1017, p.7
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`

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`US 7,658,797 B2
`
`15
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`5
`Embodiments of the present invention are directed to light
`weight concrete (LWC) compositions that includes a cemen
`titious mixture and polymer particles. Surprisingly, it has
`been found that the size, composition, structure, and physical
`properties of the expanded polymer particles, and in some
`instances their resin bead precursors, can greatly affect the
`physical properties of LWC articles made from the LWC
`compositions of the invention. Of particular note is the rela
`tionship between bead size and expanded polymer particle
`density on the physical properties of the resulting LWC
`10
`articles.
`In an embodiment of the invention, the cementitious mix
`ture can be an aqueous cementitious mixture.
`The polymer particles, which can optionally be expanded
`polymer particles, are present in the LWC composition at a
`level of at least 10, in some instances at least 15, and in other
`instances at least 20 volume percent and up to 90, in some
`cases up to 75, in other cases up to 60, in some instances up to
`50, in other instance up to 40, in particular instances up to 35,
`and in some cases up to 31 Volume percent based on the total
`volume of the LWC composition. The amount of polymer will
`vary depending on the particular physical properties desired
`in a finished LWC article. The amount of polymer particles in
`the LWC composition can be any value or can range between
`any of the values recited above.
`The polymer particles can include any particles derived
`from any suitable expandable thermoplastic material. The
`actual polymer particles are selected based on the particular
`physical properties desired in a finished LWC article. As a
`non-limiting example, the polymer particles, which can
`optionally be expanded polymer particles, can include one or
`more polymers selected from homopolymers of vinyl aro
`matic monomers; copolymers of at least one vinyl aromatic
`monomer with one or more of divinylbenzene, conjugated
`dienes, alkyl methacrylates, alkyl acrylates, acrylonitrile,
`and/or maleic anhydride; polyolefins; polycarbonates; poly
`esters; polyamides; natural rubbers; synthetic rubbers; and
`combinations thereof.
`In an embodiment of the invention, the polymer particles
`include thermoplastic homopolymers or copolymers selected
`from homopolymers derived from vinyl aromatic monomers
`including styrene, isopropylstyrene, alpha-methylstyrene,
`nuclear methylstyrenes, chlorostyrene, tert-butylstyrene, and
`the like, as well as copolymers prepared by the copolymer
`ization of at least one vinyl aromatic monomer as described
`above with one or more other monomers, non-limiting
`examples being divinylbenzene, conjugated dienes (non-lim
`iting examples being butadiene, isoprene, 1.3- and 2.4-hexa
`diene), alkyl methacrylates, alkyl acrylates, acrylonitrile, and
`maleic anhydride, wherein the vinyl aromatic monomer is
`present in at least 50% by weight of the copolymer. In an
`embodiment of the invention, styrenic polymers are used,
`particularly polystyrene. However, other suitable polymers
`can be used. Such as polyolefins (e.g., polyethylene, polypro
`pylene), polycarbonates, polyphenylene oxides, and mixtures
`thereof.
`In a particular embodiment of the invention, the polymer
`particles are expandable polystyrene (EPS) particles. These
`particles can be in the form of beads, granules, or other
`particles convenient for expansion and molding operations.
`In the present invention, particles polymerized in a suspen
`sion process, which are essentially spherical resin beads, are
`useful as polymer particles or for making expanded polymer
`particles. However, polymers derived from solution and bulk
`polymerization techniques that are extruded and cut into par
`ticle sized resin bead sections can also be used.
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`In an embodiment of the invention, resin beads (unex
`panded) containing any of the polymers or polymer compo
`sitions described herein have a particle size of at least 0.2, in
`some situations at least 0.33, in some cases at least 0.35, in
`other cases at least 0.4, in some instances at least 0.45 and in
`other instances at least 0.5 mm. Also, the resin beads can have
`a particle size of up to 3, in Some instances up to 2, in other
`instances up to 2.5, in Some cases up to 2.25, in other cases up
`to 2, in Some situations up to 1.5 and in other situations up to
`1 mm. In this embodiment, the physical properties of LWC
`articles, made according to the invention, have inconsistent or
`undesirable physical properties when resin beads having par
`ticle sizes outside of the above described ranges are used to
`make the expanded polymer particles. The resin beads used in
`this embodiment can be any value or can range between any
`of the values recited above.
`The expandable thermoplastic particles or resin beads can
`optionally be impregnated using any conventional method
`with a Suitable blowing agent. As a non-limiting example, the
`impregnation can be achieved by adding the blowing agent to
`the aqueous Suspension during the polymerization of the
`polymer, or alternatively by re-suspending the polymer par
`ticles in an aqueous medium and then incorporating the blow
`ing agent as taught in U.S. Pat. No. 2.983,692. Any gaseous
`material or material which will produce gases on heating can
`be used as the blowing agent. Conventional blowing agents
`include aliphatic hydrocarbons containing 4 to 6 carbon
`atoms in the molecule. Such as butanes, pentanes, hexanes,
`and the halogenated hydrocarbons, e.g., CFCs and HCFCs,
`which boil at a temperature below the softening point of the
`polymer chosen. Mixtures of these aliphatic hydrocarbon
`blowing agents can also be used.
`Alternatively, water can be blended with these aliphatic
`hydrocarbon blowing agents or water can be used as the sole
`blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,
`027; and 6.242.540; in these patents, water-retaining agents
`are used. The weight percentage of water for use as the blow
`ing agent can range from 1 to 20%. The texts of U.S. Pat. Nos.
`6,127,439, 6,160,027 and 6.242.540 are incorporated herein
`by reference.
`The impregnated polymer particles or resin beads are
`optionally expanded to a bulk density of at least 1.25 lb/ft
`(0.02 g/cc), in some cases 1.75 lb/ft (0.028 g/cc), in some
`circumstances, at least 2 lb/ft (0.032 g/cc) in other circum
`stances at least 3 lb/ft (0.048 g/cc) and in particular circum
`stances at least 3.25 lb/ft (0.052 g/cc) or 3.5 lb/ft (0.056
`g/cc). When non-expanded resin beads are used, higher bulk
`density beads can be used. As such, the bulk density can be as
`high as 40 lb/ft (0.64 g/cc). In other situations, the polymer
`particles are at least partially expanded and the bulk density
`can be up to 35 lb/ft (0.56 g/cc), in some cases up to 30 lb/ft
`(0.48 g/cc), in other cases up to 25 lb/ft (0.4 g/cc), in some
`instances up to 201b/ft (0.32 g/cc), in other instances up to 15
`1b/ft (0.24 g/cc) and in certain circumstances up to 10 lb/ft
`(0.16 g/cc). The bulk density of the polymer particles can be
`any value or range between any of the values recited above.
`The bulk density of the polymer particles, resin beads and/or
`prepuff particles is determined by weighing a known volume
`of polymer particles, beads and/or prepuff particles (aged 24
`hours at ambient conditions).
`The expansion step is conventionally carried out by heating
`the impregnated beads via any conventional heating medium,
`Such as steam, hot air, hot water, or radiant heat. One gener
`ally accepted method for accomplishing the pre-expansion of
`impregnated thermoplastic particles is taught in U.S. Pat. No.
`3,023,175.
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`Metromont Ex-1017, p.8
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`US 7,658,797 B2
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`The impregnated polymer particles can be foamed cellular
`polymer particles as taught in U.S. Published Application No.
`2002-01 17769 A1, the teachings of which are incorporated
`herein by reference. The foamed cellular particles can be
`polystyrene that are expanded and contain a volatile blowing
`agent at a level of less than 14 wt.%, in Some situations less
`than 6 wt.%, in some cases ranging from about 2 wt.% to
`about 5 wt.%, and in other cases ranging from about 2.5 wt.
`% to about 3.5 wt.% based on the weight of the polymer.
`An interpolymer of a polyolefin and in situ polymerized
`vinyl aromatic monomers that can be included in the
`expanded thermoplastic resin or polymer particles according
`to the invention is disclosed in U.S. Pat. Nos. 4.303,756,
`4,303,757 and 6,908,949, the relevant portions of which are
`herein incorporated by reference.
`The polymer particles can include customary ingredients
`and additives, such as flame retardants, pigments, dyes, colo
`rants, plasticizers, mold release agents, stabilizers, ultraviolet
`light absorbers, mold prevention agents, antioxidants, roden
`ticides, insect repellants, and so on. Typical pigments include,
`without limitation, inorganic pigments such as carbon black,
`graphite, expandable graphite, Zinc oxide, titanium dioxide,
`and iron oxide, as well as organic pigments such as quinac
`ridone reds and violets and copper phthalocyanine blues and
`greens.
`In a particular embodiment of the invention, the pigment is
`carbon black, a non-limiting example of such a material being
`EPS SILVER(R), available from NOVA Chemicals Inc.
`In another particular embodiment of the invention, the
`pigment is graphite, a non-limiting example of Such a mate
`rial being NEOPORR), available from BASF Aktiengesell
`schaft Corp., Ludwigshafen am Rhein, Germany.
`When materials such as carbon black and/or graphite are
`included in the polymer particles, improved insulating prop
`erties, as exemplified by higher R values for materials con
`35
`taining carbon black or graphite (as determined using ASTM
`C518), are provided. As such, the R value of the expanded
`polymer particles containing carbon black and/or graphite or
`materials made from Such polymer particles are at least 5%
`higher than observed for particles or r