The present invention relates to a flexible film fluid-dispensing liner member and a process of making such flexible film member. The flexible film fluid-dispensing liner member can be used, for example, for making a flexible film fluid-dispensing device for dispensing a fluid.
Polymeric foams, in particular polyurethane foams, are well known. In general, the preparation of a polyurethane foam requires the mixing of reactive chemical components, such as a polyol and an isocyanate, in the presence of normally used additives such as a suitable catalyst, a surfactant or cell growth control agent, and a physical and/or chemical blowing agent which permits the blowing of the foam.
In a continuous process for producing a rigid foam, and particularly in the production of rigid foams for manufacturing a foam panel structure, as currently practiced on conventional machines, it is common practice to spread or pour, via a dispenser or dispensing device, a thin layer of a reactive mixture of the foam-forming components, in a liquid state, inbetween a bottom (or lower) sheet substrate (one outer layer) and a top (or upper) sheet substrate (another outer layer) while the sheet substrates are moving for example in a lateral direction (i.e., in a horizontal plane direction).
Then, as the reactive mixture moves laterally with the bottom sheet substrate, the foam is allowed to start to rise freely, due to the reaction between the chemical components and the effect of the blowing agent, until the expansion of the foam reaches and contacts the top sheet substrate; and the foam forms a panel structure integrally attached to the top sheet substrate and the bottom sheet substrate. The foam in the panel structure is then allowed to cure; and thereafter, the panel structure is cross-sawn into panels. The foam composite panel structure typically includes, for example, a polyurethane resin (PUR) foam core or a polyisocyanurate resin (PIR) foam core. The foam core and outer layers of the panel often are also called sandwich elements or sandwich panels. A common process for the production of a composite panel structure composed of metallic outer layers (also referred to as “facers”) with a core of foam, as generally described above, includes for example, a double band lamination (DBL) process. And, depending on the type of facer on the panel, DBL can be distinguished in rigid-faced DBL (RFDBL) and flexible-faced DBL (FFDBL).
As aforementioned, the DBL process apparatus includes: (1) a lower moving sheet of a desired substrate; (2) an upper sheet of a desired substrate; and (3) a dispenser for applying a reactive foam-forming composition, which can be an emulsion, onto the lower moving sheet of the apparatus. And in general, the DBL process includes the steps of: (I) providing a reactive foam-forming composition by mixing: (a) a polyol mixture, containing polyols, catalysts, additives and gases, i.e. blowing and nucleation agents, with (b) an isocyanate, to obtain a reactive emulsion wherein the reacting liquids in the emulsion ultimately react to form the final PUR foam or PIR foam inbetween the upper (top) and lower (bottom) sheet substrates; and (II) distributing the above obtained emulsion onto the lower moving sheet of the DBL process equipment via a dispenser (also referred to as the “lay down” step). As the emulsion is distributed on the lower sheet substrate, the gases (blowing and nucleating agents) nucleate and expand via bubbles leading to the formation of the final foam that fills the gap between the two sheets, which are confined inside the double band. A dispenser means, device, or apparatus is used to distribute the PUR or PIR emulsion mixture throughout the lower moving sheet width where the foam reacts and polymerizes between the lower and upper sheets. In a short time, the foam cures to form an integral multi-layer (e.g., a three-layer) foamed panel structure. Then, the formed multilayer foamed structure is cut into blocks or sections (or “panels”) of the desired length to form the panel products.
Using a RFDBL process requires that the dispenser or dispensing device used in the process satisfy a strict set of requirements including, for example: (1) a good quality of the top surface wherein the dispenser has to provide a uniform distribution of the foam-forming reactive mixture through the panel width leading to a good aesthetic quality of the top facing sheet substrate; (2) a good working dispenser with a long operational life to provide fewer stops of a continuous process. In general. a normal operational life requirement for the dispenser is half a production shift, i.e. approximately (˜) 4 hours (hr). The operational life of the dispenser is mainly driven by fouling of the reactive mixture that partially or completely obstructs the flow within the dispenser ducts or passageways; (3) a good flexibility wherein the dispenser can serve a broad range of emulsion viscosities and flow rates; and (4) a lower dispenser cost since the dispenser article is an additional cost and such cost needs to be kept low given the fact that these devices are disposable and the current lifetime is around 4 hr.
Heretofore, a rigid solid dispensing device (also referred to as a “rake” or a “poker”) has been used to distribute a foam-forming fluid in a conventional injection molding process to make a foam product. Developments in the field of manufacturing a foam panel typically are directed only to the geometry of a dispensing device and not to technology directed to the fabrication of the dispensing device. In addition, the problem of dispenser lifetime is not addressed by the prior art. Instead, the focus of the prior art is achieving a good distribution or to decrease defects of the foam surface after the laydown step of the process. It is desired therefore to provide a flexible film member that can be used in fabricating a dispensing device suitable for dispensing a reactive fluid composition such a foam-forming fluid reaction composition.
The present invention is directed to a novel flexible film fluid-dispensing liner member that can be used to make a flexible film fluid-dispensing apparatus or device suitable for dispensing a reactive fluid composition such as a polyurethane foam-forming fluid reaction composition. The flexible film fluid-dispensing device can then be used in a production line and process for manufacturing a rigid foam multilayer panel article (structure or member).
The flexible film fluid-dispensing liner member of the present invention is also interchangeably referred to herein as a “flexible film”, a “flexible film liner”, a “flexible film distribution liner”, a “flexible distribution liner”, a “flexible film dispenser liner” or a “flexible film distributor liner”; a “flexible film dispensing liner system”, a “flexible film distribution liner system”; or simply a “liner”. Hereinafter, the flexible film fluid-dispensing liner member of the present invention will be referred to as a “flexible film fluid-dispensing liner”and abbreviated as “FFDL”.
The FFDL can be a layered article of two or more layers. For example, in one embodiment, the FFDL includes at least two layers or faces of at least two different flexible film materials which have been bonded together by various means including, for example, (1) a heat sealing process; (2) an adhesive, (3) a tie layer, or (4) a combination of any two or more of the above bonding methods. The bonding process forms a fluid flow path in the form of a series or pattern of ducts (or passageways) embedded in the FFDL. The ducts of the FFDL has at least one inlet and a plurality of outlets to allow a fluid to flow through the FFDL entering from the inlet and exiting through the outlets. For example, using any one of the above bonding processes, the ducts of the FFDL can be defined by areas in the FFDL that are not bonded together to form the ducts; for example, areas in the FFDL that are not heat sealed, areas in the FFDL that lack adhesive/glue; or areas in the FFDL that lack a bonding tie layer. The above techniques for forming a fluid flow path (ducts or passageways) through the FFDL leads to the inflating of the ducts of the FFDL when the fluid passes therethrough.
In a preferred embodiment, the FFDL of the present invention is a multilayer FFDL that includes, for example: (a) at least one first flexible film substrate layer; and (b) at least one second flexible film substrate layer; wherein the first flexible film substrate layer is bonded to the second flexible film substrate layer forming the multilayer FFDL; wherein the multilayer FFDL has a flexibility property of from 3.6E-10 Nm to 2 Nm; and (c) at least one duct having at least one inlet and a plurality of outlets (e.g., at least two outlets), the at least one duct being disposed between the first and second layers for forming a path for a fluid to pass from the at least one inlet of the duct to the plurality of outlets of the duct.
Some of the advantages of the FFDL of the present invention include, for example: (1) the FFDL is made of a material with a low affinity to polyurethane and/or polyisocyanurate which is a material that could not be previously used with known injection molding technology, (2) using a low affinity to polyurethane material advantageously to increases the dispenser lifetime; (3) by using the FFDL, a dispenser geometry can be made that could not be previously produced via injection molding; and (4) fouling of the FFDL is reduced by ducts deformation induced by increased local pressure.
As used throughout this specification, the abbreviations given below have the following meanings, unless the context clearly indicates otherwise: “=” means “equals”; “>” means “greater than”; “<” means “less than”; μm=micron(s), nm=nanometer(s), g=gram(s); mg=milligram(s); L=liter(s); mL=milliliter(s); ppm=parts per million; m=meter(s); mm=millimeter(s); °=degrees; cm=centimeter(s); min=minute(s); m/min=meters(s) per minute; s=second(s); Nm=Newtons-meters; hr=hour(s); ° C.=degree(s) Celsius; ms=milliseconds; %=percent, vol %=volume percent; and wt %=weight percent.
In one broad embodiment, the present invention includes a FFDL useful for manufacturing a flexible film fluid-dispensing device (also referred to as a flexible film fluid dispenser). The fluid that contacts the FFDL of the fluid dispenser can be any fluid such as any foamable (or foam-forming) liquid reactive mixture including PUR or PIR formulations. For example, one preferred embodiment of the present invention provides FFDL for a fluid dispenser that will receive a foam-forming reactive mixture or emulsion; and in particular, the fluid is a reactive mixture of components that react to form a polyurethane or polyisocyanurate foam such as a mixture of an isocyanate reactant and a compound that reacts with the isocyanate reactant including polyol reactants and other additives or reagents commonly used to prepare a PUR or PIR foam product.
With reference to
With reference to
The structure of each of the film substrates 10A and 10B of the FFDL of the present invention can encompass one layer or multiple layers. The material of the layers useful for manufacturing the film substrates 10A and 10B include, for example: polyethylene (i.e., PE), linear low density polyethylene (LLDPE), polyethylene terephthalate (i.e. PET), oriented polyethylene terephthalate (i.e. OPET), metalized polyethylene terephthalate (i.e. mPET), polypropylene (i.e. PP), oriented polypropylene (i.e. OPP), biaxially oriented polypropylene (i.e. BOPP), oriented polyamide (i.e., OPA)/Nylon, silicones and mixtures thereof; and/or a coextruded film structure (i.e., COEX) encompassing any or all the aforementioned film layers. In a preferred embodiment, each of the film substrates 10A and 10B can be made up of, for example, two layers such as a two-layer film structure comprising, for example, (a) a first PET layer and (b) a second PE layer.
The present invention makes it possible: (1) to use material with low affinity to polyurethane, which is a material that could not be previously used with known injection molding technology; (2) to use a material with a low affinity to polyurethane material to advantageously increase the lifetime of the FFDL; (3) to use a fluid dispensing device including the FFDL and a dispenser geometry that could not be previously produced via injection molding; and (4) to reduce fouling of the FFDL by the deformation of the ducts in response to increased local pressure.
The unique construction of the FFDL allows using both laminated and coextruded films. Therefore, each layer of a multilayer FFDL can be tailored for a specific need such as a specific stiffness and/or a specific (generally lower) chemical affinity with polyurethane. The FFDL, which includes one layer or multiple layers, can have an overall thickness appropriate for the enduse of the FFDL. For example, each layer of the FFDL can have a thickness in the range of from 20 μm to 2 mm in one general embodiment; from 50 μm to 1 mm in another embodiment; and from 60 μm to 500 μm in still another embodiment.
As aforementioned, in
The dimensions of the FFDL may vary depending on the application in which the FFDL will be used. For example, the FFDL's width w includes, for example, a width from 200 mm to 2,000 mm in one embodiment, from 800 mm to 1,350 mm in another embodiment; and from 900 mm to 1,150 mm in still another embodiment when using the FFDL for fabricating a fluid dispensing device that is used, for example, in a continuous process for manufacturing a panel member such as a RFDBL process (see
In
In one embodiment, the FFDL can be used in a fluid dispensing device such as the dispenser 40 shown in
In constructing a dispensing system using the FFDL 10 of the present invention, the flow path of the ducts 14 can be constructed and designed as appropriate for a desired application. For example, the flow path for the fluid in the FFDL is defined by the negative of the impression of a heat-sealing mold. This FFDL production technique allows to easily and inexpensively define complex and efficient flow paths otherwise impossible with standard construction methods and apparatuses such as rigid injection-molded dispensers or multi-branching pipe dispensers. The production process for the FFDL, also, allows to easily change the flow path geometry to adapt to different emulsion viscosities and/or to different flow rates. Although the ducts 14 has one inlet 15 as shown in
The flexible nature of the FFDL 10 and the system of flow ducts 14 prolong the working life of a dispenser incorporating the FFDL 10 by reducing fouling. In fact, when a duct obstruction occurs, the increased local pressure will deform the flexible walls of the FFDL ensuring the flow of the polyurethane or polyisocyanurate mixture. This phenomenon in conjunction with the low polyurethane-surface chemical affinity may also lead to the expulsion of the formed obstruction. The aforementioned phenomenon results in a relevant prolongation of the fluid dispenser's working life.
With reference to
In a preferred embodiment, the substrates 10A and 10B useful for producing the FFDL 10 described above are made of heat sealable material to provide heat-sealed areas and flexible areas for forming the pathways or ducts 14 for the FFDL 10 used to dispense a fluid flowing through the ducts 14.
In one embodiment, for example, the sealing process (temperature and pressure) need to be such that the process conditions provide the seal integrity and seal strength which allows the FFDL to withstands the pressure induced by the fluid flow. Moreover, the sealing process (e.g. pressure and temperature) needs to be such that the structural performance of the material layers close to the sealing area do not deteriorate.
In one preferred embodiment, the ducts or channels 14 can be heat welded by pressing polymeric sheets (i.e., substrates 10A and 10B) together such that the inner layers of the substrates (e.g., inner layers 12A and 12B) contact each other; and applying heating to the pressed layers for enough time to cause a weld of the two inner layers to specific areas of the pressed layer. And in so-doing, the desired ducts or channels 14 are formed for the fluid to flow in. The layers may generally be laminates of, for example, LLDPE, as the inside or inner layers 12A and 12B with another film as the outside or outer layer 11A and 11B, such as PET. The FFDL construction above would have some stiffness; however, in another embodiment, using only an LLDPE film for the substrates 10A and 10B can provide more flexibility to the FFDL if desired.
Forming the FFDL with the above materials can be carried by known techniques in the art, for example, conventional processes for making “PacXpert™” bags as described in U.S. Pat. Nos. 7,147,597B2; 8,231,029; and 8,348,509; and U.S. Patent Application Publication Nos. 2017/0247156; 2015/0314928; and 2015/0314919. In this process, two layers of a laminate are brought together and bonded using a specially designed rig, or machine in the manner described in the above patent references.
The process of making a FFDL using a laminate of, for example, 150 μm, include the following conditions: a sealing pressure of from 3 bar to 5 bar; a temperature range of heating shoe between 140° C. and 170° C. for the laminate. In another embodiment, for a monolayer of LLDPE (5056, 5400 or Elite) the temperature is about 130° C.; and a time of application is in the range of 500 ms to 1,000 ms (1 sec).
Some embodiments of the LLDPE layer include, for example, DOWLEX LLDPE 5056, DOWLEX LLDPE 5400 or DOW ELITE (all of which are available from The Dow Chemical Company). Such LLDPE used as the inside layer has a natural dis-affinity for PU (the PET layer used as the outside layer has an affinity for the PU). This desirable property is advantageous because the dis-affinity for PU property of the inside LLDPE layer reduces fouling which is a stated advantage of the design. The same LLDPE layer(s) are easy to heat bond through the application of heat and pressure as described above.
Different film structures can be conceived for the FFDL, encompassing only PE layers, PE and PET layers, PE, PET and OPA layers. In general, a sealing bar temperature comprised between 100° C. and 200° C., a sealing bar pressure comprised between 0.1 bar and 9 bar and a residence time between 0.15 s and 2 s characterizes the FFDL production process.
The FFDL 10 can be made using alternative embodiments, for example, in one embodiment and with reference to
In another embodiment, and with reference to
And, in still another embodiment, a FFDL including a combination of an adhesive layer and a tie layer (not shown) can be used to provide the bonding areas and flexible areas for forming the pathways/ducts similar to the ducts 14 of the FFDL 10 shown in
In general, the FFDL of the present invention has several advantageous properties including, for example, the FFDL: (1) is made of a flexible multilayer film structure; (2) is constructed of a durable (or strong) material; (3) has a low affinity for a polyurethane composition fluid; (4) is made of heat sealable material; (5) has dimensions such as to cover a panel width; (6) has a flow path that comprises the clearance between the distribution pipe of the dispenser and the moving metal sheet on which a fluid from the dispenser pipe has flowed thereon; (7) has a film structure that can encompass one layer or multiple layers; and (8) has a film structure that can be laminated or coextruded.
For example, the flexibility D of the FFDL is from 3.5e-10 Nm to 4 Nm in one embodiment, from 4.5e-9 to 2 Nm in another embodiment, and from 5e-5 Nm to 1 Nm in still another embodiment. The flexibility property of the FFDL is measured, for example, by the following equation:
where t is the thickness, E is the Young modulus and v is the Poisson ratio.
For example, the multilayer FFDL is made of film layers that have a strength to be functional in contacting fluid and pressures of processing fluid as measured by ASTM D1708-13 method. The strength, i.e., strain at break εbreak, of the FFDL is from 0.11 to 4 in one embodiment, from 0.18 to 8 in another embodiment, and from 0.1 to 10 in still another embodiment.
For example, the FFDL can be made of heat sealable material; and the FFDL can be heat sealed at temperatures of from 140° C. to 160° C. in one embodiment, from 100° C. to 150° C. in another embodiment, and from 110° C. to 170° C. in still another embodiment.
For example, the dimensions of the FFDL are such that the distribution of fluid covers the whole width of a panel article, or multiple FFDLs are used in order to cover the whole width of the panel. Typically, a panel width can be from 0.1 m to 2 m in one embodiment, from 0.4 m to 1.8 m in another embodiment, and from 0.9 m to 1.46 m in still another embodiment.
For example, the FFDL has a flow path that comprises the clearance between the distribution pipe of the dispenser and the moving metal sheet on which a fluid from the dispenser pipe has flowed thereon. Generally, the clearance is from 50 mm to 300 mm in one embodiment, from 15 mm to 400 mm in another embodiment, and from 100 mm to 200 mm in still another embodiment.
For example, the FFDL has a film structure that can encompass one layer or multiple layers. Generally, the number of layers of the FFDL is from 1 to 16 in one embodiment, from 1 to 14 in another embodiment, from 1 to 4 in still another embodiment, and from 1 to 3 in yet another embodiment.
For example, the FFDL has a film structure that can be manufacturing with many different types of processes; thus providing the process operator different options suitable for a particular process equipment and process conditions. For example, the layers comprising the FFDL can be laminated, coextruded or the combination of the aforementioned processes.
One of the objectives of the present invention is to provide a novel FFDL and a dispenser design incorporating the FFDL such that the design of the dispenser is technically superior in function to known prior art dispensers. The superior industrial design of the dispenser of the present invention is capable of readily dispensing an emulsion for PIR/PUR panel producers using an RFDBL continuous process.
With reference to
Various rigid materials such as plastic, metal, composites, wood, and the like, and combinations thereof, can be used to produce the frame 60; and various designs for the rigid frame member 60 which holds in place the FFDL 50 are possible. In a preferred embodiment, the FFDL 50 is removable attached to the frame member 60. For example, as shown in
For example, in
Although not shown, other embodiments of holding the FFDL in place can be readily constructed by those skilled in the art. For example, two films can be inserted within a rigid frame before the heat sealing process and then the two films and the frame can all be heat sealed together thereby the two layers of film being held in place in the frame. In another embodiment, the rigid frame can be made of two detachable halves. The FFDL is inserted between the two frame halves and then the two frame halves are reattached (e.g., clipping, binding, snapping and the like) together gripping the FFDL inbetween the two halves. In still another embodiment, the rigid frame can include side clip members incorporated all around the internal periphery of the frame that hold the FFDL in place. In yet another embodiment, the rigid frame can include two side doors/panels that are open during the insertion of the FFDL and closed during production. The doors can be transparent to allow the viewing of the flow of formulation in the ducts. The two doors may have a layer of flexible foam on the surface in contact with the FFDL in order to keep the FFDL in place.
The frame width w (as shown by dimensional arrow W in
where N is the number of the outlet ducts of the FFDL, d (as shown by arrow Y in
The connection means (preferably a hermetic connector) 70 between the FFDL and the RFDBL output pipe/pipes can be achieved with different solutions as will be apparent to those skilled in the art. For example, in one embodiment, shown in
The hermetic connection 70 further includes a nut member 74 having an internal circular ring groove 74A for receiving the flange section 71A of the fitment 71; the nut 74 being rotatably mounted on the flange section 71A of the fitment 71. The nut member 74 also includes an orifice 74B with female threads 74C for receiving a fluid production pipe member 81 having male threads for removably attaching pipe member 81 to the female threads 74C of nut member 74. Then, the nut member 74 with the fitment 71 can be threadably connected (i.e., screwed) to the pipe member 81. The connector 70 is essentially made of at least two parts. A first part of the connector 70 includes the fitment 71 with securing assembly 72 and 73 to fix the FFDL 50 to the frame 60 and to create a funnel to feed a fluid to the FFDL 50. And, a second part of the connector 70 includes a nut 74 to connect the first part that has been previously screwed to the outlet pipe member 81 of a fluid feed and production line 150 (shown in
In general, the process of fabricating the dispenser system i.e., the dispensing device 40, of the present invention includes the steps of: (A) providing a FFDL that is flexible and heat-sealable; (B) subjecting the FFDL to a heat-sealing process wherein the flow path for the fluid to be dispensed is defined by the negative impression of the sealing die; (C) providing a rigid frame for holding the FFDL in place; and (D) combining the FFDL and the rigid frame together to form the dispenser.
Some advantageous properties and/or benefits exhibited by the dispenser made by the above process of the present invention include, for example: (1) ease of production allowing the creation of complex flow path geometry otherwise impossible; (2) providing flexibility in covering different flow rate and formulations; (3) specialization of the different layer's material aiming at different performance, i.e. external layer for structural strength and integrity while interior layer with low chemical affinity with PU/PIR liquid mixture; and (4) as a consequence of the material layer specialization fouling can be reduced leading to a prolongation of the dispenser working life.
Currently, the dispenser lifetime in a typical process is about 4 hours (hr). This time period relates to the fact that the reacting flow mixture flowing through the distributor or dispenser will have zero velocities at the contact with the walls of the ducts of the FFDL of the dispenser. This means that a thin layer of fluid is stagnant at the walls of the ducts, and thus, the fluid has the time to react and to create a film of reacted material at the walls of the ducts. The reaction at the walls of the ducts reduces the internal diameter section area of the duct available for the fluid to pass through the duct, until the ducts clog completely. This phenomenon cannot be completely removed, but using materials with low affinity to PUR/PIR liquid mixtures can permit to maintain a thin film of reacted material at the walls of the ducts for a longer period of time, while the flexibility of the dispenser could permit to automatically release these reacted foam because of the higher pressure produced by the fluid, once the section area is reduced. This also permits to design the distributor geometry, without taking in account fouling problems, while currently for example velocities lower than 2.5 m/s are discouraged in order to reduce the risk of fouling (see patent US 2017/00285619 page 3 paragraph 0036), and this has a direct impact on the dispenser geometry.
In one general embodiment, the useful working life of a FFDL of the present invention and the dispenser lifetime including the FFDL is >4 hr in one embodiment; >8 hr in another embodiment; and >16 hr. In other embodiment, the FFDL of the present invention can last as much as up to 24 hr or more.
Once the dispensing device 40 has been assembled as described above, the dispenser 40 can be used in a process for producing a panel article 140 as shown in
With reference to
In one general embodiment, the process for manufacturing a panel article includes, for example, the steps of: (a) attaching the dispenser described above to a production line via the hermetic connector; (b) flowing foam-forming fluid through the dispenser; (c) dispensing the foam-forming fluid from the dispenser onto a moving bottom belt of a bottom or lower sheet substrate; (d) allowing the foam-forming fluid to react, as the fluid travels on the moving belt typically in a horizontal direction, to form a foam inbetween a top sheet substrate (top layer) and the bottom sheet substrate (bottom layer); (e) allowing the foam to contact the top and bottom layers, which are confined inside the double band, and to fill in the gap between the top and bottom layers, such that the foam is integrally connected to the top and bottom layers forming a panel structure comprising the foam material disposed inbetween the top and bottom layers; and (f) cutting the formed foamed panel from step (e) into predetermined discrete panel sections.
Polyurethane and/or polyisocyanurate foam panels can be produced using a continuous process or a discontinuous process. For example, a discontinuous process for the discontinuous production of panels is usually carried out using molds of defined shapes and sizes. The dimensions of the mold is usually between 3 m and 12 m in length, between 1 m and 2 m in width, and between 5 cm to 20 cm in thickness. In a discontinuous process, the reacting mixture is usually injected in the mold through injection hole(s); and then, the injection hole or holes are closed immediately after the injection. In some discontinuous processes, the mold is open to the atmosphere and the reacting mixture is distributed within the mold using a casting rake; and then, the mold is closed. Afterwards, the reacting mixture reacts to form a foam and as the foam is generated, the foaming mass fills the mold, while air is released through venting holes specifically positioned according to the geometry of the mold.
A continuous process is less flexible than the above-described discontinuous process; but the continuous process has a much lower cost per square meter of panel than the discontinuous process. In one embodiment, the continuous process consists of a multi-component dosing unit; a high-pressure mixing head; a laydown section, where the reacting mixture is homogeneously distributed over the full width of the band; and a heated moving conveyor to transport and cure the foam. The resulting cured foam product is then cut into sections of a predetermined length by a panel cutting section, where panels of a desired length are cut. Thereafter, the panels are stacked and stored to finalize the curing before the panels are to be packed. In the case of a rigid-faced DBL at the beginning of the line, the following steps/sections are also included: profiling, pre-heating and pre-treating (e.g. corona treatment and deposition of an adhesion promoting layer) of the metal sheets. Typical line speeds used in a continuous process are from 4 m/min to 15 m/min for RFDBL in one embodiment; and from 4 m/min up to 60 m/min for FFDBL. Temperatures used for processing PUR and PIR foam are different and can vary. In general, for example, the temperature of the metal sheets can vary between 20° C. and 80° C., while the temperature of the components is between 20° C. and 40° C. The mixing head is operated at a pressure of from about 110 bar to 170 bar in one embodiment; from 120 bar to 170 bar in another embodiment; and from 130 bar to 170 bar in still another embodiment.
In one general embodiment, the panel article can comprise one or more layers. In a preferred embodiment, for example, the panel article is a three-layer structure including (1) a top sheet substrate (top layer); (2) a bottom sheet substrate (bottom layer); and (3) a foam (middle layer) disposed inbetween the top and bottom layers and integrally connected to the top and bottom layers forming a panel structure. With reference to
Some of the advantageous properties exhibited by the panel member made by the above process of the present invention can include, for example, the panel member has: (1) more homogeneous panel properties, and (2) a reduced panel density. In addition, the use of the above-described fabrication process to manufacture panel members allows a manufacturer to design a dispensing device (or distributor) with geometries which were not possible with conventional injection molding equipment and processes; and as a result, this can have a beneficial effect on distribution of the fluid passed through the dispensing device; and therefore on the homogeneity property of the resulting panel member. Furthermore, having a better distribution of foam-forming fluid also provides the manufacturer the capability of managing foam overpacking in a better way and reducing panel applied density, which in turn, has a beneficial impact on final panel cost. Foam overpacking is described as the amount of PUR/PIR foam exceeding the minimum amount of foam needed to fill the panel thickness.
One of the major applications of PUR and PIR insulation foams is in commercial buildings wherein steel sandwich panels in some geography can be used and wherein flexible-faced panels in other geography can also be used. The panel fabrication process provides sandwich panels that exhibit a combination of thermal insulation and mechanical strength leading to building efficiency. Fire retardant performance is also an important property of sandwich panels. The sandwich panels of the present invention are useful in both industrial and residential applications, and can be used, for example, as wall and roof panels, for cold stores insulation, for doors of any type and application, for windows for sliding shutters, and the like.
Number | Date | Country | Kind |
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102019000015716 | Sep 2019 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/US2020/048886 | 9/1/2020 | WO |