Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
  • E04B1/26—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of wood
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B2/00—Walls, e.g. partitions, for buildings; Wall construction with regard to insulation; Connections specially adapted to walls
  • E04B2/56—Load-bearing walls of framework or pillarwork; Walls incorporating load-bearing elongated members
  • E04B2/70—Load-bearing walls of framework or pillarwork; Walls incorporating load-bearing elongated members with elongated members of wood
  • E04B2/706—Load-bearing walls of framework or pillarwork; Walls incorporating load-bearing elongated members with elongated members of wood with supporting function
  • E04B2/707—Load-bearing walls of framework or pillarwork; Walls incorporating load-bearing elongated members with elongated members of wood with supporting function obturation by means of panels

Definitions

• the present invention relates to vapor permeable foam, methods of using such foam for insulation in buildings and building structures containing such insulation.
• the European Energy saving directive of 2002 requires increasing insulation values of many building structures in European member states to lower energy consumption. However, it is critical to add insulation to these building structures without increasing the likelihood of vapor condensation within the building structures. Vapor condensation within a building structure can cause mold, mildew and decomposition of building structure components. Therefore, addition of any insulation to existing houses should have necessary vapor permeability .
• additional insulation it is further desirable for additional insulation to have a high compressive strength while simultaneously having a desired level of vapor permeability.
• Installation of additional insulation to existing building structures advantageously involves applying the insulation to the outside of the building structures, particularly roof structures so as to not disrupt the ability to occupy the building structure. Therefore, the insulation will desirably have enough permeability to avoid vapor condensation in the building structure while at the same time have sufficient compressive strength to support the weight of materials and workers applying the insulation without damage.
• increasing the vapor permeability of a polymer foam decreases the foam's compressive strength.
• increasing the vapor permeability can lead to a lower compressive strength and a higher thermal conductivity.
• USP United States patent
• USP 6145255 disclose soffit ventilation systems that can include an open cell foam in order to allow for ventilation while preventing egress of insects into an attic space. It is unclear whether the foam of these patents is rigid or flexible. Moreover, a foam in such a soffit applications desirably would have high thermal conductivity (low insulating value) to prevent trapping of heat in an attic space.
• Great Britain patent (GB) 1396182 and GB 1396582 disclose open cell foam structures suitable for applications requiring vapor transmission.
• the foams are prepared from a solution by dissolving a polymer into a solvent.
• GB 1396182 achieves an example having a 95% void volume (and a density of approximately 50 kilograms per cubic meter (kg/m ) assuming the polymer composition has a specific gravity of approximately one gram per cubic centimeter) that is "tough".
• Australian patent application AU2006203389 discloses a perforated foam sheet suitable for insulation where moisture permeability is desirable.
• the reference discloses several embodiments of a foam that differ in cell size and, likely, other properties.
• One type of foam has a cell structure whose cells are cylindrical in shape with a diameter between about eight millimeters and 25 millimeters. A foam with such a large cell size will have poor thermal insulating properties due to high convection of heat through the cells.
• the other type of foam in this reference is a closed-cell foam having an average cell size of less than 0.1 millimeters and that is flexible and capable of rolling up.
• the present invention is the result of surprisingly discovering a foam that is especially well suited for insulating a building structure, particularly retro- insulating a building structure, because the foam concomitantly has a vapor permeability sufficiently high to allow water vapor to escape the building structure while also having a low enough thermal conductivity to serve as a thermal insulator and a compressive strength sufficient to support materials and workers during installation.
• the present invention is a building structure comprising: (a) multiple support members spaced apart from one another so that two neighboring support members have a space between them and each support member having opposing inside and outside surfaces; and (b) a thermoplastic polymer foam spanning the space between two neighboring support members and attached to the outside surface of two or more of the support members; wherein, the thermoplastic polymer foam: (i) has a resistance to water vapor permeability value that is less than 50 according to EN 12086; (ii) a thermal conductivity that is less than 40 milliwatts per meter*Kelvin as measured according to EN12667; (iii) a compressive strength greater than 80 kilopascals as measured according to EN 826; and (iv) a density of 48 kilograms per cubic meter or less according to EN 1602.
• Embodiments of the first aspect of the present invention may have any one or any combination of more than one of the following characteristics: the thermoplastic polymer foam has a continuous polymer phase comprising an alkenyl aromatic polymer; the building structure is free of a vapor barrier component having a water vapor permeability value higher than 50 as measured according to EN12086 and that extends across two or more support members spanned by the thermoplastic polymer foam; the thermoplastic polymer foam has a resistance to water vapor permeability of 10 or more; the thermoplastic polymer foam is further characterized by having a density of 24-48 kilograms per cubic meter according to ISO 845-95; the thermoplastic polymer foam is further characterized by having an open cell content of 40% or more and 100% or less according to ASTM D2856; the thermoplastic polymer foam is further characterized by having a thickness of 50 millimeters or more; the building structure is one or more structure selected from a group consisting of roof structures and wall structures; the building structure is a timber frame wall structure; the building structure is
• the present invention is a method for insulating a building structure comprising the following steps: (a) providing multiple support members spaced apart from one another so that two neighboring support members have a space between them and each having opposing inside and outside surfaces; (b) providing a thermoplastic polymer foam that has a resistance to water vapor permeability that is less than 50 as measured according to EN12086, a thermal conductivity that is less than 40 milliwatts per meter*Kelvin as measured according to EN 12667, a compressive strength that is greater than 80 kilopascals as measured according to EN 826, and a density of 48 kilograms per cubic meter or less according to EN 1602; and (c) attaching the thermoplastic polymer foam to two or more of the support members such that the foam spans the space between two neighboring support members .
• Embodiments of the second aspect can have any one or any combination of more than one of the following characteristics: the thermoplastic polymer foam has a continuous polymer phase comprising an alkenyl aromatic polymer; the thermoplastic polymer foam has a resistance to water vapor permeability value of 10 or more; the thermoplastic polymer foam is further characterized by having a density of 24-48 kilograms per cubic meter according to EN 1602; the thermoplastic polymer foam is further characterized by having an open cell content of 40% or more and 100% or less according to ASTM D2856; the thermoplastic polymer foam is further characterized by having a thickness of 50 millimeters or more; the building structure is one or more structure selected from a group consisting of roof structures and wall structures; the building structure is a timber frame wall structure; and the building structure is a pitched roof structure .
• the present invention has particular utility in insulating building structures by either building new or by adding insulation to existing structures in order to meet higher thermal insulting requirements and demands while avoiding hazards associated with retaining water within a building structure.
• ASTM refers to American Society for Testing and Materials. ASTM test methods refer to the test method of the year noted by the hyphenated suffix after the test method number or the most recent test method prior to filing this application.
• Internal and “inside” refer to a side that is most proximate to a space defined by (hence, within) a building structure. In a home structure, the “inside” or “internal” side is the side facing the dwelling side of the structure that is typically heated in cold portions of the year.
• External or outside refers to a side that is opposite the internal or inside and that is most remote from a space defined by a building structure.
• the external or outside portion of a building element is most proximate to the natural environment in which the building structure is built.
• Span means to extend all the way across. To span a space between two support members means to extend from one support member across the space to the other support member. Resistance to water vapor permeability is in adimensional units of "mu” or " ⁇ " . Each unit of mu is equal to the resistance of water vapor permeability through standing air. Determine mu for a given material according to the general procedure of EN 12086-95. Foam Insulation
• Thermoplastic polymer foam for use in the present invention can be any type of foam, including expanded polymer bead foam or extruded polymer foam.
• an expandable polymer bead process prepare a foamable composition by incorporating a blowing agent into granules of polymer composition (for example, imbibing granules of polymer composition with a blowing agent under pressure) . Subsequently, expand the granules in a mold to obtain a foam composition comprising a multitude of expanded foam beads (granules) that adhere to one another to form a "bead foam". The granules can experience some level of foaming prior to expansion within a mold to form a bead foam. Alternatively, expand the beads apart from a mold and then fuse them together thermally or with an adhesive within a mold.
• Bead foam has a characteristic continuous network of polymer skin corresponding to the surface of each individual bead extending throughout the foam. Extrusion processes are most desirable. Foams made from expandable foam bead processes have a network of polymer skins (bead skins) that define and enclose groups of cells within the foam. Such skins are residual skins from each foam bead that expanded to form the foam. The bead skins coalesce together to form a foam structure comprising multiple expanded foam beads. Bead foams tend to be more friable than extruded foam because they can fracture along the bead skin network. Moreover, the bead skin network provides a continuous thermal short from any one side of the foam to an opposing side, which is undesirable in a thermal insulating material.
• Extruded foams are continuous, seamless structures free from having, for example, the network of bead skins characteristic of expanded bead foam.
• An extruded foam can be a "strand foam". That is, the extruded foam may comprise multiple extruded strands of foam that are fused together.
• a strand foam has a polymer network skin extending along the extrusion direction of the foam but not in a direction perpendicular to the extrusion direction.
• a strand foam is free of a continuous polymer skin (which can cause a thermal short) extending all the way through the strand foam in a direction perpendicular to the extrusion direction as there is in an expanded bead foam.
• it is most desirable that the extruded foam be a continuous, seamless structure as opposed to a bead foam structure or other composition comprising multiple individual foams that are assembled together in order to maximize structural integrity and thermal insulating capability.
• a foamable composition by mixing a thermoplastic polymer composition and, optionally, additives in an extruder at a temperature sufficiently high to soften the polymer composition, and then mixing in a blowing agent at an addition pressure sufficient to preclude appreciable expansion of the polymer composition. It is acceptable to either feed additives directly into the extruder or to pre-mix additives with a polymer prior to addition to an extruder (i.e., compound it or create a masterbatch) . It is desirable to then cool the foamable composition to a foaming temperature and then expel the foamable composition through a die into an environment of lower pressure than the addition pressure. As the foamable composition enters the environment of lower pressure it expands into a polymer foam.
• Blowing agents are typically present in a combined concentration of 0.001 mole per 100 grams of polymer to 0.5 mole per 100 gram of polymer.
• Suitable blowing agents for use in an extrusion foaming process include one or more of the following: inorganic gases such as carbon dioxide, argon, nitrogen, and air; organic blowing agents such as water, aliphatic and cyclic hydrocarbons having from one to nine carbons including methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclobutane, and cyclopentane; fully and partially halogenated aliphatic hydrocarbons having from one to five carbons, preferably that are chlorine-free (e.g., difluoromethane (HFC-32), perfluoromethane, ethyl fluoride (HFC-161), 1,1,- difluoroethane (HFC-152a) ,
• the polymer foam may contain any individual or combination of the following additives: infrared attenuating agents (for example, carbon black, graphite, metal flake, titanium dioxide); clays such as natural absorbent clays (for example, kaolinite and montmorillonite) and synthetic clays; nucleating agents (for example, talc and magnesium silicate); flame retardants (for example, brominated flame retardants such as hexabromocyclododecane, phosphorous flame retardants such as triphenylphosphate, and flame retardant packages that may including synergists such as, or example, dicumyl and polycumyl); lubricants (for example, calcium stearate and barium stearate); and acid scavengers (for example, magnesium oxide and tetrasodium pyrophosphate) .
• infrared attenuating agents for example, carbon black, graphite, metal flake, titanium dioxide
• clays such as natural absorbent clays (for example
• a preferred flame retardant package includes a combination of hexahalocyclododecane (for example, hexabromocyclododecane) and tetrabromobisphenol A bis (2, 3-dibromopropyl ether.
• the polymer foam has a thermal conductivity of 40 milliwatts per meter*Kelvin (mW/m*K) or less, preferably, 35 mW/m*K or less. Lower thermal conductivity values are desirable to maximize thermal insulating capability for the foam. The lower the thermal conductivity of a foam, the less thickness is necessary to achieve a given measure of thermal insulation. Measure thermal conductivity at 1O 0 C mean temperature according to test method EN 8301-91.
• the polymer foam has a compressive strength greater than 80 kilopascals (kPa) , preferably 120 kPa or more, more preferably 170 kPa or more, still more preferably 200 kPa or more.
• Measure compressive strength according to ASTM D-1621-04. Higher compressive strengths are desirable in an insulating foam over lower compressive strengths in order to provide durability during handling, installation and use.
• the compressive strength of present thermoplastic polymer foams renders them rigid foams.
• flexible foams are not suitable alternatives to the thermoplastic polymer foams for use in the present invention. Flexible foams necessarily have an undesirably low compressive strength in order to flex and, therefore, cannot sustain loads in a roofing application without deformation or inhibit racking in walls like the present thermoplastic polymer foam.
• the polymer foams of the present invention have properties that surprisingly balance conflicting effects of achieving a low thermal conductivity and high compressive strength (typically achieved using a closed-cell foam with low permeability) with achieving vapor permeability through the foam that is high enough provide for more water vapor to permeate through the foam than is retained from permeating through the foam.
• Polymer foams of the present invention have a resistance to water vapor permeability ("mu" or " ⁇ ") of 50 or less, preferably 40 or less more preferably 30 or less as measured according to EN 12086-95.
• the foam can have a mu value of 20 or less. Higher mu values correspond to foams having lower water vapor permeability.
• the polymer foam When the mu value is greater than 50 the polymer foam generally will have too low of a water vapor transmission capability and water condensate will likely build up proximate to a building structure on which the foam resides. At the same time, it is desirable not to have too low of a mu value or the thermal insulating value of the foam becomes too low to be of value and, typically, the compressive strength decreases. Hence, it is desirable for the foam to have a mu value of 10 or more.
• the polymer foam desirably has an open cell content of 40% or more, preferably 50% or more, more preferably 60% or more. Measure open cell content according to American Society for Testing and Materials (ASTM) method D2856.
• the polymer foam has an open cell content of 100% or less, more typically 80% or less.
• the polymer foam can have an open cell content below
• the polymer foam can have an open cell content of 0%. However, if the open cell content is too low to achieve the necessary mu value then the foam must undergo perforation so as to provide perforations though the foam to increase water vapor permeability.
• the thermoplastic foams are not perforated but rather have an inherent open cell structure (that is, an open cell structure resulting from expansion of the cells during manufacture) .
• Inherently open cell foams have a torturous path through the cell structures from one side to the other of the foam without a linear paths through from one side to the other.
• perforated foams have linear paths through the foam from one side to the other where perforating needles penetrate through the foam.
• the perforation are preferably 2 millimeters or less in diameter in order to minimize detrimental effect on (that is, increase in) thermal conductivity. When the perforations are 2 millimeters or less in diameter, airflow does not occur extensively enough to effect thermal conductivity. Nonetheless, water vapor can still permeate effectively through the perforations.
• the polymer foam has a density of 64 kilograms per cubic meter (kg/m ) or less, preferably 40 kg/m or less, more preferably 30 kg/m or less. Measure foam density according to ISO 845-95. Lower density foams are desirable because they contribute less weight to building structures, and weight can be a particular concern for roof structures. Low density foams are also desirable for easier handling and shipping. Typically, the polymer foam has a density of 20 kg/m 3 or more in order to ensure sufficient compressive strength and durability.
• the foam desirably has a thickness of at least 15 millimeters, preferably at least 30 millimeters and more preferably at least 50 millimeters in order to provide optimal insulating value and also provide structural integrity to the building structure (for example, to provide stability against racking in timber frame structures).
• the thermoplastic polymer foam has a continuous polymer phase that desirably comprises or consists of one or more than one alkenyl aromatic polymer.
• the continuous polymer phase includes all polymers present in the thermoplastic foam at a concentration greater than 20 wt% based on the thermoplastic polymer foam weight. Polymers present at a concentration less than 20 wt% of the thermoplastic polymer foam are considered additives in the continuous polymer phase as opposed to part of the continuous polymer phase.
• a continuous polymer phase may "consist of" styrenic polymers even though there are non-styrenic polymer additives present at a concentration less than 20 wt% of the thermoplastic polymer foam weight.
• An alkenyl aromatic polymer contains polymerized alkenyl aromatic monomer units and includes homopolymers and copolymers containing alkenyl aromatic monomer units (i.e., made from monomers that include alkenyl aromatic monomers).
• Polystyrene (PS) based polymers that is, PS homopolymer and copolymers
• PS homopolymer and copolymers are one particularly preferred class of alkenyl aromatic polymers.
• Particularly desirable PS polymers are PS homopolymer and PS copolymer with acrylonitrile (styrene- acrylonitrile copolymer (SAN) ) .
• the present thermoplastic polymer foam is free of a continuous polymer phase that consists of polyethylene (PE) , polypropylene (PP) or a combination of PE and PP.
• PE polyethylene
• PP polypropylene
• the modulus of most PE and PP polymers is too low to provide a thermoplastic polymer foam having a combination of vapor permeability, compressive strength and thermal conductivity of the present thermoplastic polymer foam.
• the present thermoplastic foam typically has an average cell size that is greater than 50 microns, preferably greater than 70 microns, and is more preferably 100 microns or larger, still more preferably 200 microns or larger.
• the average cell size is desirably 2000 microns or smaller, preferably 1000 microns or smaller, more preferably 500 microns or smaller.
• thermal conductivity and density tend to increase undesirably due a large amount of polymer in a given through the foam's cross section.
• thermal conductivity tends to begin to increase due to convention through the foam. Measure average cell size according to American Society for Testing and Materials method D-3576. Insulated Building Structure
• thermoplastic polymer foam is useful for insulating building structures.
• the thermoplastic polymer foam offers advantages over other insulating foam when applied to the outside of a building where thermal insulation needs to be permeable to water vapor in order to allow vapor to escape to the atmosphere from between the insulating foam and building structure.
• thermal insulation needs to be permeable to water vapor in order to allow vapor to escape to the atmosphere from between the insulating foam and building structure.
• insulating foam applied to the outside to prevent water vapor build-up and condensation between the insulating foam and building structure.
• thermoplastic polymeric foam is particularly useful for applying to structure from the outside because it allows water vapor to escape from the structural elements/insulation within the structure. Therefore the present thermoplastic polymeric foam is especially suited for modifying existing structures to increase insulation (that is, "retro-insulating" existing structures ) .
• thermoplastic foam can be applied onto any building structure in any manner. However, it is particularly useful for spanning two or more ("multiple") support members of a building structure that are spaced apart from one another. For example, roof rafters and wall joists are examples of support members of a building structure.
• the high compressive strength of the present thermoplastic foams make the present thermoplastic foams well suited for supporting loads even between support members without breaking.
• an insulating thermoplastic foam having a high vapor permeability like the present foam does not have sufficient compressive strength to support loads between support members.
• thermoplastic foam spanning the space between two neighboring support members and attached to the outside surface of two or more of the support members is unique and offers a desirable structure having a combination of high insulating ability, high compressive strength and vapor permeability.
• the thermoplastic foam is useful for insulating, particularly retro-insulating, pitched roofs on building structures such as houses by attaching to outside surfaces of roof structural elements. Roof structures typically comprise spaced apart structural elements such as rafters or furring strips spanning rafters.
• Pitched roof structures of the present invention may comprise, in addition to the structural elements and present thermoplastic foam, at least one of the following additional elements: a breathable membrane and finishing elements (such as shingles, battens and tiles) with the thermoplastic foam between the additional element or elements and the structural elements.
• additional element or elements are desirably attached to the thermoplastic foam, which is attached to the structural element such that the thermoplastic foam is between the additional element (s) and the structural elements .
• the present thermoplastic polymer foam is ideally suited for insulating wall structures from the outside, which is particularly desirable in retro-insulating building structures.
• the vapor permeability of the present thermoplastic polymer foam allows moisture to escape.
• the compressive strength of the present thermoplastic polymer foam strengthens the wall structure against deformation by, for example, racking.
• additional insulation may be present in a cavity defined by neighboring structural elements.
• inter-joist or inter-rafter cavities may contain mineral wool or fiberglass or other fibrous insulation while the present thermoplastic polymer foam spans the outside surface of the joists, rafters, or other structural elements defining the cavity.
• Method of Insulating a Building Structure Prepare building structures of the present invent by providing multiple support members spaced apart from one another so to form a space between them and each having opposing inside and outside surfaces, providing a present thermoplastic polymer foam and attaching the thermoplastic polymer foam to two or more of the support members such that the foam spans the space between two support members.
• a single foam may span the space between more than one pair of neighboring support members.
• the support members can be of any composition, with common materials being wood (for example, lumber joists and studs) and metal (for example, metal joists and studs) .
• the present thermoplastic foam may directly contact the support member or may be separated from the support member by anything that has a vapor permeability no less than that of the present thermoplastic polymer foam.
• pph weight-parts per hundred weight parts copolymer
• pph 0.25 pph polyethylene
• 0.20 pph copper blue phthalocyanine 0.12 pph tetrasodium pyrophosphate
• Table 1 also identifies properties for Sample 2, a polystyrene foam.
• a roofing structure having spaced apart rafters, optionally containing fiberglass or mineral wool insulation between the rafters, optionally containing a batten structure affixed on the inside of the roof structure that provides a level surface for plaster or plaster boards to be affixed as the substructure for the inside walls of the structure. Battens are also affixed to the outer surface of the structure to which roofing material such as tiles or shingles are attached.
• this roofing structure increases the insulation of this roofing structure by first removing the roofing material (for example, tiles or shingles) and battens on the outside of the rafters. Affix by means of an adhesive or mechanical fastener (for example, nails or screws) to multiple rafters a styrene-based polymer foam board (for example, either of Sample 1 or Sample 2) that has a resistance to water vapor permeability that is less than 50 as measured according to EN12086, a thermal conductivity that is less than 40 milliwatts per meter*Kelvin a measured according to EN 12667, a compressive strength that is greater than 80 kilopascals as measured according to EN 826 and a density of 48 kilograms per cubic meter or less according to EN 1602 so that the polymer foam board entirely spans two or more rafters.
• a styrene-based polymer foam board for example, either of Sample 1 or Sample 2 that has a resistance to water vapor permeability that is less than 50 as measured according to EN
• rafters are covered with polymeric foam and there is no spacing between polymeric foam boards.
• roofing materials such as tiles, shingles or metal sheet over the battens .

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• 2009
  • 2009-01-15 US US12/809,655 patent/US20100313507A1/en not_active Abandoned
  • 2009-01-15 EP EP09703816A patent/EP2238301A2/de not_active Withdrawn
  • 2009-01-15 CN CN2009801029131A patent/CN101925708B/zh not_active Expired - Fee Related
  • 2009-01-15 WO PCT/US2009/031038 patent/WO2009094280A2/en active Application Filing
  • 2009-01-15 JP JP2010544372A patent/JP2011510199A/ja not_active Ceased

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