Patent Application
20180355613
In the construction of naturally lit structures (e.g., greenhouses, pool enclosures, solar roof collectors, conservatories, stadiums, sunrooms, industrial buildings, residential buildings and so forth), glass can be employed as a transparent structural element, e.g., windows, facings, and roofs. However, polymer sheeting can replace glass in many applications due to several notable benefits.
Glass panel roofing systems generally provide good light transmission and versatility. However, the initial and subsequent costs associated with these systems can limit their application and overall market acceptance. The initial expenses associated with glass panel roofing systems can include the cost of the glass panels themselves as well as the cost of the structure, or structural reinforcements, that are employed to support their weight. After these initial expenses, operating costs associated with the inherently poor insulating ability of the glass panels can result in higher heating expenses for the owner. Yet further, glass panels are susceptible to damage caused by impact or shifts in the support structure (e.g., settling), which can result in high maintenance costs.
Disclosed herein are multiwall sheets, such as high stiffness and lightweight multiwall sheets, articles, and methods of making the same.
In an embodiment, a multiwall sheet comprises a first wall; a second wall; a plurality of ribs extended between the first and second walls; and a plurality of mid-ribs, wherein one mid-rib extends between each two adjacent ribs, wherein the mid-ribs extend at a mid-rib angle relative to an adjoining rib, and wherein the mid-rib angle is not 90° relative to a rib to which it attaches, and wherein the mid-ribs attach only to adjacent ribs.
The above described and other features are exemplified by the following figures and detailed description.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are exemplary embodiments, not necessarily drawn to scale, are meant to be illustrative and not limiting, and wherein the like elements are numbered alike.
Multiwall polymeric panels have been produced that can exhibit improved impact resistance, ductility, insulative properties, and can have lower weight than comparatively sized glass panels. As a result, these characteristics can reduce operational and maintenance expenses. Polymer sheeting can reduce breakage and maintenance costs in applications wherein occasional breakage caused by vandalism, hail, contraction/expansion, and the like, is encountered. Polymer sheeting can have reduced weight compared to glass. This can make polymer sheeting easier to install in comparison to glass and can reduce the load-bearing requirements of the structure on which they are installed. Additionally, polymer sheeting can provide improved insulative properties compared to glass which can reduce heating and/or cooling costs and positively impact overall market acceptance of polymer sheeting.
Low weight multiwall sheets that possess high stiffness to weight ratio without significantly affecting other performance characteristics (optical, thermal, acoustic, and the like) are desired in the industry.
Multiwall sheets can be efficient structures for use in roof and wall panels. Various arrangements of multiwall sheet internal components to improve the performance have been previously attempted. Lightweight multiwall sheets can reduce manufacturing and installation cost, yet to effectively resist service loads without requiring additional supporting structure, these sheets can depend on high stiffness. The lightest conceived multiwall sheet consists of three walls with ribs there between to connect the walls into a single sheet. In such a three wall configuration weight reduction with improved stiffness can be challenging due to limited degrees of freedom in the structural design.
Examples of known multiwall sheets are shown in US published application 2013/0089710, US published application US 2013/0052429, US published application 2013/0017361, and U.S. Pat. No. 7,614,186. The entirety of these patents and patent applications are incorporated herein by reference.
Multiwall sheets exhibiting both low weight and high load carrying capacity can drive increased acceptance and use of multiwall sheets in building and industrial applications. Disclosed herein are multiwall sheets having minimal internal members. These sheets can provide exceptional flexural rigidity while minimizing the size and number of internal members thereby minimizing sheet weight. The design of these sheets optimizes the placement of internal members to further reduce weight while retaining high stiffness.
To achieve low weight, multiwall sheets were developed with minimum number of internal parts. Ribs, located between the outer walls of the multiwall sheet, reinforce the walls to resist deflection under an applied load (i.e. provide increased sheet flexural stiffness). Additional mid-ribs, also called an internal mid skin, extend between the ribs to provide support to the ribs by simultaneously providing additional orthotropic stiffness and resistance to nonlinear mid plane stretching (i.e. stretching along the natural axis of the sheet). The beneficial effects of the mid-ribs can be further increased by slanting the mid-rib non-parallel to the wall, and connecting the mid-rib directly to adjacent ribs, where the mid rib is free of attachment to the outside walls of the multiwall sheet.
The mid-ribs can divide the internal structure between adjacent ribs of the sheet into two cells (versus a single cell when only ribs, and no mid-ribs, are present). In addition to providing improved flexural structural rigidity the mid-ribs can also add a thermal break (e.g., barrier) between the outer walls of the multiwall sheet, which can increase the resistance to energy being transferred perpendicularly through the wall. The mid-rib can offer an improved thermally insulative characteristic to the multiwall sheet in comparison to sheets without a mid-rib (e.g., particularly in the case of a low conductance plastic multiwall sheets). Furthermore, by slanting the mid-rib and attaching the mid-rib only to adjacent ribs and not to the outer walls of the sheet, the thermal insulation property of the sheet can be improved relative to multiwall sheets where mid-ribs attach to the outer walls. The characteristics (e.g. thermal, acoustic, or optical characteristics) of the multiwall sheet can be further manipulated through the use of fillers or surface treatments.
The multiwall sheet can be formed from a plastic material, such as thermoplastic resins, thermosets, and combinations comprising at least one of the foregoing. The multiwall sheet walls, ribs and mid-ribs can be formed from the same plastic material or can be formed from different plastic materials (e.g., plastics having a different chemical formula, chemical composition, or the like). Plastic material can be chosen which have similar coefficients of thermal expansion to reduce the occurrence of damage due to differences in thermal expansion between the walls, ribs, and/or mid-ribs.
Possible thermoplastic resins that may be employed to form the multiwall sheet walls, ribs, and mid-ribs include, but are not limited to, oligomers, polymers, ionomers, dendrimers, copolymers such as graft copolymers, block copolymers (e.g., star block copolymers, random copolymers, and the like) and combinations comprising at least one of the foregoing. Examples of such thermoplastic resins include, but are not limited to, polycarbonates (e.g., blends of polycarbonate (such as, polycarbonate-polybutadiene blends, copolyester polycarbonates)), polystyrenes (e.g., copolymers of polycarbonate and styrene, polyphenylene ether-polystyrene blends), polyimides (e.g., polyetherimides), acrylonitrile-styrene-butadiene (ABS), polyalkylmethacrylates (e.g., polymethylmethacrylates (PMMA)), polyesters (e.g., copolyesters, polythioesters), polyolefins (e.g., polypropylenes (PP) and polyethylenes, high density polyethylenes (HDPE), low density polyethylenes (LDPE), linear low density polyethylenes (LLDPE)), polyamides (e.g., polyamideimides), polyarylates, polysulfones (e.g., polyarylsulfones, polysulfonamides), polyphenylene sulfides, polytetrafluoroethylenes, polyethers (e.g., polyether ketones (PEK), polyether etherketones (PEEK), polyethersulfones (PES)), polyacrylics, polyacetals, polybenzoxazoles (e.g., polybenzothiazinophenothiazines, polybenzothiazoles), polyoxadiazoles, polypyrazinoquinoxalines, polypyromellitimides, polyquinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines (e.g., polydioxoisoindolines), polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polypyrrolidones, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polyphthalamide, polyacetals, polyanhydrides, polyvinyls (e.g., polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polyvinylchlorides), polysulfonates, polysulfides, polyureas, polyphosphazenes, polysilazanes, polysiloxanes, fluoropolymers (e.g., polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), fluorinated ethylene-propylene (FEP), polyethylene tetrafluoroethylene (ETFE)) and combinations comprising at least one of the foregoing.
More particularly, the thermoplastic resin used in the multiwall sheet walls, ribs, and mid-ribs can include, but is not limited to, polycarbonate resins (e.g., Lexan™ resins, commercially available from SABIC Innovative Plastics), polyphenylene ether-polystyrene resins (e.g., Noryl™ resins, commercially available from SABIC Innovative Plastics), polyetherimide resins (e.g., Ultem™ resins, commercially available from SABIC Innovative Plastics), polybutylene terephthalate-polycarbonate resins (e.g., Xenoy™ resins, commercially available from SABIC Innovative Plastics), copolyestercarbonate resins (e.g. Lexan™ SLX resins, commercially available from SABIC Innovative Plastics), and combinations comprising at least one of the foregoing resins. Even more particularly, the thermoplastic resins can include, but are not limited to, homopolymers and copolymers of a polycarbonate, a polyester, a polyacrylate, a polyamide, a polyetherimide, a polyphenylene ether, or a combination comprising at least one of the foregoing resins. The polycarbonate can comprise copolymers of polycarbonate (e.g., polycarbonate-polysiloxane, such as polycarbonate-polysiloxane block copolymer), linear polycarbonate, branched polycarbonate, end-capped polycarbonate (e.g., nitrile end-capped polycarbonate), and combinations comprising at least one of the foregoing, for example, a combination of branched and linear polycarbonate.
The multiwall sheet walls, ribs, and mid-ribs can include various additives ordinarily incorporated into polymer compositions of this type, with the proviso that the additive(s) are selected so as to not significantly adversely affect the desired properties of the sheet, in particular, transparency, deflection, stress, and flexural stiffness. Such additives can be mixed at a suitable time during the mixing of the components for forming the multiwall sheet. Exemplary additives include impact modifiers, fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, ultraviolet (UV) light stabilizers, plasticizers, lubricants, mold release agents, antistatic agents, colorants (such as carbon black and organic dyes), surface effect additives, radiation stabilizers (e.g., infrared absorbing), flame retardants, and anti-drip agents. A combination of additives can be used, for example a combination of a heat stabilizer, mold release agent, and ultraviolet light stabilizer. In general, the additives are used in the amounts generally known to be effective. The total amount of additives (other than any impact modifier, filler, or reinforcing agents) is generally 0.001 wt % to 5 wt %, based on the total weight of the composition of the multiwall sheet.
In addition to flexural stiffness, deflection, and lower edge stress, the polymeric material can be chosen to exhibit sufficient impact resistance such that the sheet is capable of resisting breakage (e.g., cracking, fracture, and the like) caused by impact (e.g., hail, birds, stones, and so forth). Therefore, polymers exhibiting an impact strength greater than or equal to about 7.5 foot-pounds per square inch, ft-lb/int (4.00 Joules per square centimeter, J/cm2), or more specifically, greater than about 10.0 ft-lb/int (5.34 J/cm2) or even more specifically, greater than or equal to about 12.5 ft-lb/int (6.67 J/cm2) are desirable, as tested per ASTM D-256-93 (Izod Notched Impact Test). Further, desirably, the polymer has ample stiffness to allow for the production of a sheet that can be employed in applications wherein the sheet is generally supported and/or clamped on two or more edges of the sheet (e.g., clamped on all four edges), such as in greenhouse applications comprising tubular steel frame construction. Sufficient stiffness herein is defined as polymers comprising a Young's modulus (e.g., modulus of elasticity) that is greater than or equal to about 1×109 N/m2, or, more specifically, 1×109 to 20×109 N/m2, or, still more specifically, 2×109 to 10×109 N/m2.
The multiwall sheet can be transparent, depending upon the desired end use. For example, multiwall sheet can have a transparency of greater than or equal to 80%, specifically, greater than or equal to 85%, or, more specifically, greater than or equal to 90%, or, even more specifically, greater than or equal to 95%, or, still more specifically, greater than or equal to 99%. Transparency is described by two parameters, percent transmission and percent haze. Percent transmission and percent haze for laboratory scale samples can be determined using ASTM D1003-00, procedure B using CIE standard illuminant C. ASTM D-1003-00 (Procedure B, Spectrophotometer, using illuminant C with diffuse illumination with unidirectional viewing) defines transmittance as:
wherein: I=intensity of the light passing through the test sample
A multiwall sheet can be formed from various polymer processing methods, such as extrusion or injection molding, if produced as a unitary structure. Continuous production methods, such as extrusion, generally offer improved operating efficiencies and greater production rates than non-continuous operations, such as injection molding. Specifically, a single screw extruder can be employed to extrude a polymer melt (e.g., polycarbonate, such as Lexan*, commercially available from SABIC Innovative Plastics). The polymer melt can be fed to a profile die capable of forming an extrudate having the cross-section of the multiwall sheet 30 illustrated in any of the FIGS. The multiwall sheet 30 travels through a sizing apparatus (e.g., vacuum bath comprising sizing dies) and is then cooled below its glass transition temperature (e.g., for polycarbonate, about 297° F. (147° C.)).
After the panel has cooled, it can be cut to the desired length utilizing, for example, an extrusion cutter such as an indexing in-line saw. Once cut, the multiwall sheet can be subjected to secondary operations before packaging. Exemplary secondary operations can include coating, embossing, replication, annealing, printing, attachment of fastening members, trimming, further assembly operations, and/or any other desirable processes. The size of the extruder, as measured by the diameter of the extruder's screw, is based upon the production rate desired and calculated from the volumetric production rate of the extruder and the cross-sectional area of the panel. The cooling apparatus can be sized (e.g., length) to remove heat from the extrudate in an expeditious manner without imparting haze.
Haze can be imparted when a polymer (e.g., polycarbonate) is cooled rapidly. Therefore, the cooling apparatus can operate at warmer temperatures (e.g., greater than or equal to about 100° F. (39° C.), or more specifically, greater than or equal to 125° F. (52° C.), rather than colder temperatures (e.g., less than 100° F. (39° C.), or more specifically, less than or equal to about 75° F. (24° C.)) to reduce hazing. If warmer temperatures are employed, the bath length can be increased to allow ample time to reduce the extrudate's temperature below its glass transition temperature. The size of the extruder, cooling capacity of the cooling apparatus, and cutting operation can be capable of producing the multiwall sheet at a rate of greater than or equal to about 5 feet per minute. However, production rates of greater than about 10 feet per minute, or even greater than about 15 feet per minute can be achieved if such rates are capable of producing surface features that comprise the desired attributes.
Coextrusion methods can also be employed for the production of the multiwall sheet. Coextrusion can be employed to supply different polymers to any portion of the multiwall sheet's geometry to improve and/or alter the performance of the sheet and/or to reduce raw material costs. One skilled in the art would readily understand the versatility of the process and the myriad of applications in which coextrusion can be employed in the production of multiwall sheets.
A more complete understanding of the components, processes, and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures (also referred to herein as “FIG.”) are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments. Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.
The multiwall sheet width W can be measured along the w-axis dimension. The multiwall sheet length L can be measured along the l-axis dimension. The multiwall sheet thickness T can be measured along the t-axis dimension. The sheet thickness T can be measured from the outside surface 40 of the first wall 2 to the outside surface 43 of the second wall 4. The ribs 8 of the multiwall sheet 30 can extend between the first and second walls and can be perpendicular to the first and second wall or, the ribs 8 can be substantially perpendicular to the first and second walls (e.g. not perfectly perpendicular to the first and second walls across the width W of the multiwall sheet 30, accommodating for slight variations in the orientation during processing). The distance between ribs, or rib spacing, Lo can be uniform (e.g. equal throughout the length of the multiwall sheet, or substantially equal accommodating slight variations in rib thicknesses resulting from processing) or, the rib spacing Lo can be non-uniform.
The total sheet thickness T of the multiwall sheet as measured in the t-axis dimension (see
The first and second wall thicknesses, T2 and T4, as measured along the t-axis direction (see
The mid-rib thickness T6 as measured in the direction perpendicular to the plane of a given mid-rib (see
The rib thickness T8 as measured along the l-axis direction (see
The first initial offset distance 16 of the mid-rib 6 can be 1%-99% of the multiwall total sheet thickness T, for example 5% to 95%, or, 10% to 90%.
The first terminal offset distance 20 of the mid-rib 6 can be 1%-99% of the multiwall total sheet thickness T, for example 5% to 95%, or, 10% to 90%.
The second initial offset distance 14 of the mid-rib 6 can be 1%-99% of the multiwall total sheet thickness T, for example 5% to 95%, or, 10% to 90%.
The second terminal offset distance 22 of the mid-rib 6 can be 1%-99% of the multiwall total sheet thickness T, for example 5% to 95%, or, 10% to 90%.
The Applicants found that when the mid-rib 6 was attached at the point where the first wall 2 (or second wall 4) and a rib 8 connected (the corner formed between a wall and a rib) that material would accumulate in the corners, due to practical limitations of forming the sheet. The accumulation of material increased the sheet weight without improving the structural, thermal, acoustic, or optical performance of the sheet. By moving the mid-rib 6 attachment point away from the corner, offsetting the mid-rib 6 from the wall, the sheet could be formed without excess material and the sheet properties would be maximized for a given unit weight (also called specific weight, specific sheet weight, or weight per sheet area).
When the mid-ribs 6 are oriented as declined mid-ribs 46 the plane in which each declined mid-rib 46 lies can be parallel, or can be nonparallel. The mid-rib angle 18 of each declined mid-rib 46 can be equal along the length of the multiwall sheet 30 measured along the l-axis or, the mid-rib angle of declined each mid-rib can be unequal along the length of the sheet measured along the l-axis.
The mid-rib angle 18 can define the orientation of the mid-rib relative to an adjacent rib. For the sake of clarity the mid-rib angle 18 has been measured relative to the left hand side rib 8 to which the mid-rib attaches. This mid-rib angle 18 can be any angle greater than 0° and less than 180° (relative to the rib 8 from which the mid-rib angle 18 is measured). The mid-ribs 6 can extend between the ribs 8 wherein the mid-ribs 6 do not attach to either outer wall of the multiwall sheet (i.e. the mid-rib does not directly attach to either outer wall 2 or 4). Still more specifically, the mid-ribs can be inclined 36 or declined 46 (as shown in
Additionally, the rib spacing Lo can be greater than, equal to, or less than the gauge of the multiwall sheet (i.e. multiwall sheet thickness T) and can vary along the length L of the sheet. Specifically, the rib spacing Lo can be 25%-400% of the multiwall sheet thickness T, for example, 50% to 200%, or, 75% to 150%, or, 95% to 105%, or, 100%.
The rib spacing Lo can be the length of a mid-rib 6 projected onto l-axis and measured along the l-axis, (e.g., the horizontal length of the mid-rib). The mid-rib height 26 (MRH) can be the length of a mid-rib 6 projected onto the t-axis and measure along the t-axis, (e.g., the vertical length of the mid-rib). The dimensional parameters of the mid-ribs 6 can also be defined in terms of a mid-rib angle 18, a rib spacing Lo, and a mid-rib height 26 (MRH) or any combination comprising two of the foregoing parameters by using basic trigonometric functions. For example, the mid-rib height 26 can be determined from the rib spacing Lo and the mid-rib angle 18, or the rib spacing Lo can be determined from the mid-rib height 26 and the mid-rib angle 18, or the mid-rib angle 18 can be determined from the mid-rib height 26 and the rib spacing Lo by using the tangent relationship between the three parameters when the rib 8 is perpendicular to the first wall 2:
Where, θ=the mid-rib angle 18 for inclined mid-ribs 36, or
A repeating mid-rib pattern as used herein can refer to a pattern comprising adjacent inclined mid-ribs 36, or adjacent declined mid-ribs 46. An alternating mid-rib pattern as used herein can refer to a pattern comprising at least one inclined mid-rib 36 adjacent to at least one declined mid-rib 46. A multiwall sheet 30 can be comprised of a repeating mid-rib pattern, an alternating mid-rib pattern, or a combination comprising at least one of the foregoing patterns. Furthermore, the initial and terminal offset distances of each mid-rib can vary from mid-rib 6 to mid-rib 6 (e.g., the initial and terminal offset distances of adjacent mid-ribs can be different).
The disclosed structural parameters (e.g., wall thicknesses, rib thicknesses, mid-rib thicknesses, mid-rib angles, overall sheet thickness, offset distances, mid-rib patterns (e.g., alternating, repeating or combinations comprising at least one of the foregoing), or a combination including at least one of the foregoing) can be adjusted to achieve a desired multiwall sheet performance and/or physical characteristic (e.g. stiffness, deflection, heat transfer, optical characteristic, acoustic characteristic, weight, dimension, and the like). These adjustments can be made locally (e.g., within selected areas of a multiwall sheet 30) and/or throughout the entire multiwall sheet 30 to attain the desired multiwall sheet performance.
The multiwall sheet disclosed herein can be formed as an integral sheet through an extrusion (e.g., co-extrusion) or the components of the multiwall sheet can be formed separately and fashioned together with any well-known technique.
The multiwall sheet disclosed herein can exhibit very similar deflection under suction and pressurized conditions when the force under each condition has the same magnitude acting normal to the sheet. A “suction” condition as used herein can refer to when a side of the multiwall sheet is exposed to pressure below the pressure acting on the opposite side of the sheet. A “pressurized” condition as used herein can refer to when a side of the multiwall sheet is exposed to a pressure above the pressure acting on the opposite side of the sheet. The only difference between these two conditions is the direction of the force vector acting on the sheet and consequently the direction of displacement (if any). Under a suction condition the absolute value of the displacement can be 75% to 125% of the displacement under a pressurized condition of the same magnitude (i.e. the size of the force, or length of the force vector, not the direction in which the force is acting) for example, 90% to 110%, or, 95% to 105%, or, 99% to 101%. The multiwall sheet can provide similar performance under both suction and pressure loading conditions. Such similar performance under opposing forces can reduce or eliminate the need to mistake-proof (e.g., identifying an outer side, inner side, and the like) the sheets to avoid improper installation.
Rib spacing can relate to light transmission, or optical clarity, and stiffness. Stiffness can improve with reduced rib spacing and optical clarity can improve with increase rib spacing. Thus, rib spacing can be optimization for a given end use or multiwall sheet application.
Computational analysis was used to predict the deflection performance of rectangular multiwall sheets which were secured continuously along all four edges of the sheet to an engagement distance of 24 mm. The analysis simulated a wind load of 1000 N/m2 and the resulting maximum deflection was predicted for each sheet. The sheets were each 980 mm in length, and width was greater than two times the length. The samples tested had different total sheet, wall, rib, and mid-rib thicknesses. In addition to varying thicknesses, the mid-rib height, and slanting distance (analogous to second initial offset distance 14 in
1TST = Total Sheet Thickness (analogous to gauge or sheet thickness T)
2ST = Skin Thickness (analogous to wall thickness T2, T4)
3RD = Rib Distance (analogous to rib spacing Lo)
4RT = Rib Thickness
5MD = Mid-rib Distance (analogous to mid-rib height 26)
6SD = Slanting Distance (analogous to second initial offset distance 14 in FIG. 2)
7DT = Mid-rib Thickness
Computational nonlinear structural analysis was performed on multiwall sheets of
Computational nonlinear structural analysis was performed on multiwall sheets of the configuration shown in
Set forth below are examples of the multiwall sheets described herein, articles comprising the same, and methods of making the same.
A multiwall sheet comprising: a first wall; a second wall; a plurality of ribs extended between the first and second walls; and a plurality of mid-ribs, wherein one mid-rib extends between each two adjacent ribs, wherein the mid-ribs extend at a mid-rib angle relative to an adjoining rib, and wherein the mid-rib angle is not 90° relative to a rib to which it attaches, and wherein the mid-ribs attach only to adjacent ribs.
The multiwall sheet of Embodiment 1, wherein an initial end of a mid-rib is attached to a first rib at a first initial offset distance measured from a inside surface of the first wall.
The multiwall sheet of Embodiment 2, wherein the first initial offset distance is 10% to 90% of a total sheet thickness.
A multiwall sheet of and of Embodiments 1-3, wherein adjacent mid-ribs form a mid-rib pattern comprising a repeating mid-rib pattern, an alternating mid-rib pattern, or a combination comprising at least one of the foregoing patterns.
A multiwall sheet of any of Embodiments 1-4, wherein the sheet has a total sheet thickness of 4 mm to 100 mm.
A multiwall sheet of any of Embodiments 1-5, wherein the first wall has a thickness of 0.1 mm to 10 mm.
A multiwall sheet of any of Embodiments 1-6, wherein the second wall has a thickness of 0.1 mm to 10 mm.
A multiwall sheet of any of Embodiments 1-7, wherein the plurality of ribs each has a thickness of 0.1 mm to 10 mm.
A multiwall sheet of any of Embodiments 1-8, wherein the plurality of mid-ribs each has a thickness of 0.02 mm to 2 mm.
A multiwall sheet of any of Embodiments 1-9, wherein the sheet comprises a plastic material.
A multiwall sheet of any of Embodiments 1-9, wherein the sheet comprises a plastic material, and wherein the plastic material comprises homopolymers and copolymers of a polycarbonate, a polyester, a polyacrylate, a polyamide, a polyetherimide, a polyphenylene ether, or a combination comprising at least one of the foregoing.
A multiwall sheet of any of Embodiments 1-11, wherein a maximum sheet deflection is less than or equal to 70 mm at a wind pressure of 1000 N/m2.
A multiwall sheet of any of Embodiments 1-12, wherein a maximum sheet deflection is less than or equal to 51 mm at a wind pressure of 1000 N/m2.
A multiwall sheet of any of Embodiments 1-13, wherein a maximum sheet deflection is less than or equal to 38 mm at a wind pressure of 1000 N/m2.
A multiwall sheet of any of Embodiments 1-14, wherein a sheet deflection under a suction condition is 75% to 125% of the sheet deflection under a pressurized condition of the same magnitude as the suction condition.
A multiwall sheet of any of Embodiments 1-15, wherein a rib spacing is 10% to 1000% of a total sheet thickness.
A multiwall sheet of any of Embodiments 1-15, wherein a rib spacing is 75% to 125% of a total sheet thickness.
A multiwall sheet of any of Embodiments 1-15, wherein a rib spacing is equal to a total sheet thickness.
A multiwall sheet of any of Embodiments 1-18, wherein the mid-rib angle is 5° to 85°, preferably 10° to 70°, preferably 20° to 45°.
A multiwall sheet of any of Embodiments 1-19, wherein the mid-rib angle is 95° to 175°, preferably 100° to 160°, preferably 110° to 135°.
A multiwall sheet of any of Embodiments 1-20, wherein the mid-ribs are between the first wall and the second wall.
A multiwall sheet of any of Embodiments 1-21, wherein the first wall and the second wall are free of attachments to the mid-ribs.
A multiwall sheet of any of Embodiments 1-22, wherein the mid-ribs do not attach to either the first or second walls.
An article comprising the multiwall sheet of any of Embodiments 1-23.
A method of making a multiwall sheet, comprising: forming a multiwall sheet; wherein the multiwall sheet comprises a first wall; a second wall; a plurality of ribs extended between the first and second walls; and a plurality of mid-ribs, wherein one mid-rib extends between each two adjacent ribs, wherein the mid-ribs extend at a mid-rib angle relative to an adjoining rib, and wherein the mid-rib angle is not 90° relative to a rib to which it attaches, wherein the mid-ribs attach only to adjacent ribs, and wherein the mid-ribs do not attach to either the first or second walls.
The method of Embodiment 25, wherein forming a multiwall sheet comprises extruding, coextruding, injection molding or a combination comprising at least one of the foregoing.
The method of any of Embodiments 25-26, further comprising cutting the multiwall sheet.
The method of any of Embodiments 25-27, further comprising processing the multiwall sheet in a secondary operation.
In general, the invention may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present invention.
All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of “up to 25 wt. %, or, more specifically, 5 wt. % to 20 wt. %”, is inclusive of the endpoints and all intermediate values of the ranges of “5 wt. % to 25 wt. %,” etc.). “Combination” is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to denote one element from another. The terms “a” and “an” and “the” herein do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the film(s) includes one or more films). Reference throughout the specification to “one embodiment”, “another embodiment”, “an embodiment”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2016/057689 | 12/15/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62269120 | Dec 2015 | US |
