Method for producing molded polymer foams

Abstract

The present invention is a method for manufacturing a molded polymer foam, in particular a laminate comprising a central foam layer and a facing layer on one or both sides. A flexible film dispenser (10) is folded or wound and introduced into a mold cavity (7) through an opening (6) in the mold. The dispenser is deployed or spread within the mold cavity, and a foam precursor is pumped through the dispenser and into the mold cavity. The dispenser has a plurality of outlets (16) through which the foam precursor enters the mold cavity. This allows the foam precursor to be distributed more uniformly throughout the mold cavity and reduce defects while improving product quality.

Description

[0001] The present invention relates to a process for producing molded polymer foams.

[0002] Many polymer foams are made by introducing a precursor fluid into a mold where it expands and solidifies to produce a polymer.

[0003] Product quality often depends on obtaining uniform distribution of the precursor fluid in the mold before it hardens and can no longer flow. Uneven distribution can lead to defects, reduced performance, and even scrapped parts.

[0004] Dispensing precursor fluids is often a challenge. This problem becomes particularly acute when producing large, thin parts such as laminates. Laminates, which can be single-sided or double-sided, are materials that include a polymer foam layer and a facing layer bonded to one or both sides of the foam layer. Due to the insulating properties of the foam layer, these products can be used as thermal insulation boards.

[0005] Laminates are usually manufactured in industry in a continuous process. A typical continuous process is often referred to as double belt lamination. In this process, the problem of obtaining a uniform, although usually imperfect, distribution of the precursor fluid is solved by using a distribution system that distributes the precursor fluid through a plurality of outlets. The outlets are arranged over the width of the bottom facing layer and are now usually fixed. The bottom facing layer moves horizontally under the outlets. This movement produces a strip of foam formulation on the bottom facing layer from each outlet. The foam formulation then expands to produce foam. Ideally, the individual strips meet and combine to form a continuous layer as they expand, and they then solidify to the point where they can no longer flow. If desired, a top facing layer can be applied after the precursor fluid has been distributed but before it solidifies to form a double-sided laminate.

[0006] For example, dispensing systems that can be used in continuous lamination processes are described in EP2125323A, EP2234732A, WO 2021 / 045888, WO 2021 / 046019, WO 2021 / 046020, WO 2021 / 046021, and WO 2012 / 046022. WO 2021 / 046019, WO 2021 / 046020, WO 2021 / 046021, and WO 2012 / 046022 all describe flexible dispensers made by bonding polymer films together in a manner that creates conduits and multiple outlets.

[0007] In contrast, some laminates are made in a discontinuous process. Discontinuous processes are often used to produce products with non-standard sizes or geometries and other special items that cannot be easily produced in a continuous process. In a discontinuous process, the bottom and optional top facing layers are horizontally oriented to define the opposite major sides of the mold. The facing layers are separated by frame members that define the sides of the mold. The facing layers and frame members together define a closed space to be filled with a precursor fluid. The precursor fluid is dispensed into the closed space and cured. The frame member is then separated from the resulting panel. The top and bottom facing layers remain adhered to the polymer foam layer.

[0008] Dispensing systems, such as those used in continuous laminate production, are not useful in discontinuous processes because it is difficult to introduce a dispenser into the mold and remove it after the precursor fluid has been dispensed into the mold cavity. Instead, the precursor fluid is typically introduced into the mold cavity through one or more openings in a frame member. This typically results in poor distribution of the precursor fluid because the precursor fluid must flow over a considerable distance on the mold from the edge into which it is injected to the opposite edge and laterally. The so-called "spray gun" and "take-out" methods attempt to alleviate this problem by inserting a hollow spray gun into the interior of the mold and introducing the precursor fluid through the spray gun. The spray gun can be gradually removed as the mold cavity is filled. These methods reduce the distance that the precursor must flow in one dimension rather than laterally and are therefore not entirely satisfactory.

[0009] In one aspect, the present invention is a method for making a molded polymer foam, the method comprising the steps of:

[0010] a) introducing a folded or rolled multilayer film fluid dispenser into a mold cavity through a mold opening, wherein the multilayer film fluid dispenser comprises

[0011] (i) at least one first flexible film substrate layer and

[0012] (ii) at least one second flexible film substrate layer,

[0013] The first flexible film base layer is bonded to the second flexible film base layer, thereby forming

[0014] forming a multi-layer membrane component; and

[0015] (iii) at least one conduit in fluid communication with at least one inlet and a plurality of outlets, the at least one conduit being disposed between the first flexible membrane substrate layer and the second flexible membrane substrate layer and forming one or more pathways for fluid to pass from the at least one inlet of the conduit through the multilayer membrane member to the plurality of outlets of the conduit;

[0016] b) unfolding or spreading the multilayer film fluid dispenser inside the mold; and

[0017] c) flowing a polymer foam precursor fluid into the at least one inlet, through the at least one conduit of the unfolded or spread multilayer film fluid distributor, and out of the plurality of outlets into the mold cavity;

[0018] A curing step is then performed by curing the polymer foam precursor fluid introduced into the mold cavity through the multilayer film fluid dispenser to produce a molded polymer foam in the mold cavity.

[0019] Figure 1A-1F are top views, partially in section, which together schematically illustrate one embodiment of the method of the present invention.

[0020] Figure 2 is a front cross-sectional view of a first multi-layer film fluid dispenser used in the present invention.

[0021] Figure 3 is along Figure 2 A side sectional view taken along line 3-3.

[0022] Figure 4 is along Figure 2 A side sectional view taken along line 4-4.

[0023] Figure 5A is a front cross-sectional view illustrating the insertion of a second multi-layer film fluid dispenser for use in the present invention into a mold cavity.

[0024] Figure 5B is a front cross-sectional view illustrating the second multi-layer film fluid dispenser fully inserted into the mold cavity.

[0025] Fig. 6A is a front cross-sectional view of a third multi-layer film fluid dispenser used in the present invention.

[0026] Figure 6B is a front cross-sectional view of the third multi-layer film fluid dispenser fully inserted into the mold cavity.

[0027] Fig. 7A is a front cross-sectional view illustrating the insertion of a fourth multi-layer film fluid dispenser used in the present invention into a mold cavity.

[0028] Figure 7B is a front cross-sectional view illustrating the fourth multi-layer film fluid dispenser fully inserted into the mold cavity.

[0029] Turning to FIG. 1 , the mold 1 includes a bottom mold surface 2, a top mold surface 3, and mold sides 4, which together define a mold cavity 7. A mold opening 6 is provided in one of the mold sides 4. Figure 1Aand Figure 1B As shown, a folded or rolled multilayer film fluid dispenser 10 is inserted into a mold cavity 7 through a mold opening 6. The multilayer film fluid dispenser 10 is fluidly connected to an upstream distribution system (not shown) via a conduit 11, through which a polymer foam precursor fluid is directed into a conduit 14 via an inlet 15 (see FIG. Figure 2 ).

[0030] Referring again to Figure 1, Figure 1B and Figure 1C As shown, the multilayer film fluid dispenser 10 is unfolded or spread out after being inserted into the mold cavity 7. In its fully unfolded or spread out state, the multilayer film fluid dispenser 10 preferably spans at least 50%, at least 75%, or at least 90% of the width W of the mold cavity 7. As described below, various methods can be used to unfold or spread out the multilayer film fluid dispenser 10.

[0031] Refer to Figure 1 and Figure 2 , the multilayer film fluid dispenser 10 includes a conduit 14 that defines a plurality of fluid paths from an inlet 15 through the multilayer film fluid dispenser 10 to an outlet 16. After the multilayer film fluid dispenser 10 is inserted into the mold cavity 7 and deployed or spread out, the polymer foam precursor fluid flows into the multilayer film fluid dispenser 10 from an upstream distribution system (not shown) via the conduit 11 via the inlet 15, and from there flows out of the plurality of outlets 16 of the deployed or spread out multilayer film fluid dispenser 10 through the conduit 14 and into the mold cavity 7. This produces a jet 20 of the polymer foam precursor fluid.

[0032] Adjacent jets 20 of polymer foam precursor fluid may be parallel to each other or have a small deviation from parallel, such as up to 20°. A single jet 20 of polymer foam precursor fluid expands and combines with adjacent jets 20 to form a continuous mass 50 of polymer foam precursor fluid within the mold cavity 7.

[0033] exist Figure 2 In the particular embodiment shown, the conduit 14 is a branching system, wherein the conduit 14 includes branch points at which the conduit is divided to define a plurality of flow paths. Figure 2 In the illustrated embodiment, seven such branch points are arbitrarily illustrated, at each branch point, the incoming stream of polymer foam precursor fluid is divided into two streams. The branching conduit system may include as few as one such branch point and any arbitrarily greater number of branch points, such as at least 2, at least 3, at least 4, at least 5, at least 7, at least 10, at least 15, or at least 31, and for example up to 100, up to 50, or up to 25 branch points. For purposes of the present invention, a "branch point" is simply a point within conduit 14 at which the polymer foam precursor fluid, or a portion thereof, is divided into two or more streams (preferably exactly two) as it passes through the conduit system.

[0034] Figure 2 The illustrated embodiment includes a preferred feature that all flow paths from inlet 15 to outlet 16 have the same length. Due to this feature, the residence time of the polymer foam precursor fluid is the same or very nearly the same for each of the flow paths, and the polymer foam precursor fluid arrives at each of the outlets 16 in the same or very nearly the same state of solidification. In the same state of solidification, the polymer foam precursor fluid exiting each of the outlets 16 at any point in time has the same or very nearly the same viscoelastic properties.

[0035] The number of flow paths into which the polymer foam precursor fluid is divided within the distribution system can be as few as 2, and can be any arbitrarily larger number, such as at least 2, at least 3, at least 4, at least 5, at least 7, at least 8, at least 10, at least 16, or at least 32, and for example up to 100, up to 50, or up to 25. Similarly, the number of outlets 16 can be as few as 2, and can be any arbitrarily larger number, such as at least 2, at least 3, at least 4, at least 5, at least 7, at least 8, at least 10, at least 16, or at least 32, and for example up to 100, up to 50, or up to 25. In FIG. 5 , the number of fluid paths and outlets 16 is arbitrarily shown as 8.

[0036] The outlets 16 may be arranged in a straight line, in a staggered configuration, or in other useful configurations.

[0037] In some embodiments, outlets 16 are evenly spaced along the width of the multilayer film fluid dispenser 10. The center-to-center distance between adjacent outlets 16 can be, for example, 10 mm to 300 mm, and a preferred distance is 10 mm to 200 mm, 30 mm to 200 mm, or 50 mm to 150 mm. The center-to-center distance between two outermost outlets 16 can be, for example, 20 cm to 200 cm, 20 cm to 150 cm, or 20 cm to 120 cm. The center-to-center distance between two outermost outlets 16 can be, for example, 80% to 98% of the width W of the mold cavity 7.

[0038] The embodiment illustrated in FIG. 1 includes the following optional features: (1) allowing the unfolded or spread multilayer film fluid dispenser 10 to extend at least partially through the mold cavity 7 to the distal end 8 (eg, Figure 1C ), and (2) then taking the expanded or unrolled multilayer film fluid dispenser 10 away from the distal end 8 and toward the mold opening 6 as the polymer foam precursor fluid is dispensed from the outlet 16 and into the mold cavity 7. These preferred features help to more evenly distribute the polymer foam precursor fluid over the entire length L of the mold cavity 7.

[0039] like Figure 1C As shown, in this embodiment, before the flow of the polymer foam precursor fluid is initiated, the expanded or spread multilayer film fluid dispenser 10 is moved toward the distal end 8 of the mold cavity 7. Before the flow of the polymer foam precursor fluid is initiated, the expanded or spread multilayer film fluid dispenser 10 may be inserted into the length L of the mold cavity 7, for example, at least 50%, at least 75%, or at least 90% (i.e., at least 50%, at least 75%, or at least 90% of the distance from the mold opening 6 to the distal end 8). The flow of the polymer foam precursor fluid is then initiated to generate a jet 20 of the polymer foam precursor fluid, which expands and coalesces to form a continuous mass 50. The continuous mass 50 is then directed toward the mold opening 6 (as shown in the direction indicated by arrow 22). Figure 1D and 1E The multilayer film fluid dispenser 10 is gradually withdrawn (as shown) while the polymer foam precursor is continuously or intermittently dispensed from the outlet 16 and into the mold cavity 7. The multilayer film fluid dispenser 10 can be taken out at the same rate as the mold cavity 7 is filled with the polymer foam precursor fluid.

[0040] The removal method illustrated in FIG. 1 is optional. In an alternative embodiment, the multilayer film fluid dispenser 10 is maintained in a constant position within the mold cavity 7 during the entire time that the polymer foam precursor fluid is being dispensed. Thus, for example, instead of positioning the multilayer film fluid dispenser 10 near the distal end 8 of the mold cavity 7 and gradually removing it (e.g., Figure 1C , Figure 1D and Figure 1E Instead, the multilayer film fluid dispenser can be held in a fixed position within the mold cavity 7, such as adjacent to the mold opening 6, as shown. Figure 1E shown.

[0041] Sufficient polymer foam precursor fluid is introduced into mold cavity 7 through an expanding or spreading multilayer film fluid dispenser 10 to completely fill mold cavity 7 after the polymer foam precursor fluid has expanded and cured to produce a molded polymer foam.

[0042] like Figure 1F As shown, after the necessary amount of polymer foam precursor fluid is introduced into the mold cavity 7, the multilayer film fluid dispenser 10 is removed from the mold cavity 7 through the mold opening 6. It is usually necessary to refold or rewind the multilayer film fluid dispenser 10 to remove it through the mold opening 6.

[0043] Prior to removing the multilayer film fluid dispenser 10, the space within the mold cavity 7 occupied by the multilayer film fluid dispenser is typically filled with the polymer foam precursor fluid because the polymer foam precursor fluid further expands within the mold cavity 7 after removing the multilayer film fluid dispenser 10 but before curing is complete. This further expansion reduces or eliminates defects in the molded polymer foam in the area occupied by the multilayer film fluid dispenser 10 before it was removed.

[0044] The polymer foam precursor fluid solidifies within the mold cavity to produce a molded polymer foam product.

[0045] Now go to Figure 2-Figure 4 The multilayer film fluid dispenser 10 includes a first flexible film substrate 10A and a second flexible film substrate 10B. Figure 2-Figure 4 In the embodiment shown, each of the flexible film substrates 10A and 10B is a multilayer structure, which is an optional but preferred embodiment. The film substrates 10A, 10B may have a plurality of constituent layers, or may have only one constituent layer. As shown, the flexible film substrate 10A is composed of an inner layer 12A and an outer layer 11A, and the flexible film substrate 10B is composed of an inner layer 12B and an outer layer 11B. The flexible film substrates 10A and 10B are bonded to each other via the inner layers 12A and 12B, so that the surfaces 13A and 13B of the outer layers 11A and 11B face the outside, respectively.

[0046] The conduit 14 is produced by bonding (e.g., by a heat sealing process) portions of the flexible film substrate 10A to the second film substrate 10B via the interior layers 12A and 12B at predetermined spaced-apart locations to form bond lines such as the bond line 13E. Due to the bonding process, the conduit 14 is formed by the unbonded surface portions 13C and 13D of the interior layers 12A and 12B. The conduit 14 formed by the selective bonding process is embedded between the first flexible film substrate 10A and the second flexible film substrate 10B.

[0047] Multilayer flexible fluid distribution liner components and methods of manufacturing the same are further described in WO 2021 / 046019.

[0048] The conduit 14 is in fluid communication with at least one inlet 15 for receiving a polymer foam precursor fluid from an upstream device (not shown) such as a mixing head. The conduit 14 is further in fluid communication with a plurality of outlets 16 for discharging the polymer foam precursor fluid into the mold cavity 7. The plurality of outlets 16 and the inlet 15 are in fluid communication via the conduit 14.

[0049] exist Figure 2In the specific embodiment shown, the blind tube 18 is configured as a device for unfolding or spreading the multilayer film fluid dispenser 10. The blind tube 18 is characterized by being in fluid communication with the conduit 14 (as shown) or the inlet 15 (which can be the same inlet as the conduit 14 or a separate inlet) and having no associated outlet. The blind tube 18 extends outward from the central portion of the multilayer film fluid dispenser 10 toward its lateral edges 19 and 19A. The polymer foam precursor fluid entering the blind tube 18 from the conduit 14 and / or the inlet 15 is captured in the blind tube 18. When the folded or rolled multilayer film fluid dispenser 10 is inserted into the mold cavity 7 and the polymer foam precursor fluid begins to flow into the multilayer film fluid dispenser 10, the blind tube 18 is filled with the polymer film precursor fluid. The polymer foam precursor fluid captured in the blind tube 18 mechanically unfolds or spreads the multilayer film fluid dispenser 10 in the mold cavity 7. In such an embodiment, after the mold cavity 7 is filled with the polymer foam precursor fluid, the multilayer film fluid dispenser is preferably removed from the mold cavity 7 within a short period of time before the polymer foam precursor fluid solidifies within the blind tube 18, making it difficult to refold or rewind the multilayer film fluid dispenser 10.

[0050] exist Figure 2 In a variation of the illustrated embodiment, the blind tube 18 is not fluidly connected to the conduit 14 and / or the inlet 15, but is fluidly connected to a separate inlet port through which a separate expansion fluid (such as air, another gas or a liquid) is pumped into the blind tubes 18 to expand them and unfold or spread the multilayer film fluid dispenser 10 in the mold cavity 7.

[0051] Alternatively, the dead leg 18 and other separate equipment for deploying or spreading the multilayer film fluid dispenser 10 may be omitted, in which case the polymer foam precursor fluid flowing through the conduit 14 provides sufficient hardening to deploy or spread the multilayer film fluid dispenser 10 .

[0052] In place of or in addition to the blind tube 18, a mechanical device for unfolding or spreading the multilayer film fluid dispenser 10 may be provided. Examples of such mechanical devices include various types of spring systems and other mechanical actuators. FIG. 5 illustrates one such alternative embodiment. An arm 36 is pivotally attached at a pivot point 40 at or near the lateral sides 19 and 19A of the multilayer film fluid dispenser 10 and is pivotally mounted at a fixed position in the upstream direction of the multilayer film fluid dispenser 10. In the specific embodiment shown in FIG. 5 , the arm 36 is pivotally mounted to the pipe 11 at a pivot point 37. Instead of being mounted directly on the pipe 11, the pivot point 37 may be attached to other equipment, such as an external housing, a collar, a sheath, etc., which is located at a fixed position in the upstream direction of the multilayer film fluid dispenser 10. The spring mechanism may be provided at the pivot points 40 and / or 37. As Figure 5AAs shown, the arm 36 is retained in the collar 41 to hold the multilayer film fluid dispenser 10 in a folded or rolled position. The collar 41 is slidably mounted around the conduit 11, the arm 36 and the multilayer film fluid dispenser 10. The multilayer film fluid dispenser 10 passes through the mold opening 6 and enters the mold cavity 7 (in the direction indicated by the arrow A). Figure 5B ).like Figure 5B As shown, a collar 41 that is larger than the mold opening 6 engages and is held by the mold side 4, thereby remaining outside the mold cavity 7. The arm 36, no longer constrained by the collar 41, extends laterally due to the action of the spring mechanism, thereby unfolding or spreading the multilayer film fluid dispenser 10 within the mold cavity 7. After the mold filling step is completed, the tube 11 and the multilayer film fluid dispenser 10 are removed from the mold cavity 7 by moving them in the direction shown by the arrow B. The pivot point 37 and the arm 36 are removed through the collar 41 and through the mold opening 6, pushing the pivot point 40 inwardly, and refolding or rewinding the multilayer film fluid dispenser 10 so that it can be removed through the mold opening 6.

[0053] In the embodiment shown in Figure 6, the spring 61 mechanically actuates the unfolding or spreading of the multilayer fluid dispenser 10. The spring 61 is attached at or near the lateral sides 19 and 19A of the multilayer film fluid dispenser 10 at the attachment point 63 and is mounted at a fixed position in the upstream direction of the multilayer film fluid dispenser 10. In the specific embodiment shown in Figure 6, the spring 61 is mounted to the pipe 11 at the attachment point 62. Instead of being directly mounted to the pipe 11, the spring 61 can be pivotally attached to other equipment, such as an external housing, a collar, a sheath, etc., which is located at a fixed position in the upstream direction of the multilayer film fluid dispenser 10. The spring 61 and the multilayer film fluid dispenser 10 are retained in the sheath 64 to maintain the multilayer film fluid dispenser 10 in a folded or rolled position prior to insertion. The sheath 64 is slidably mounted around the pipe 11, the spring 61 and the multilayer film fluid dispenser 10. The multilayer film fluid dispenser 10 passes through the mold opening 6 and enters the mold cavity 7. As Figure 6B As shown, a sheath 64 that is larger than the mold opening 6 engages and is held by the mold side 4, thereby remaining outside the mold cavity 7. The spring 61, no longer constrained by the sheath 64, expands laterally, thereby unfolding or spreading the multilayer film fluid dispenser 10 within the mold cavity 7. After the mold filling step is completed, the tube 11 and the multilayer film fluid dispenser 10 are removed from the mold cavity 7 by moving them in the direction indicated by the arrow B. The spring 61 and the multilayer film fluid dispenser 10 are retracted into the sheath 64, pushing the attachment point 63 inwardly, and refolding or rewinding the multilayer film fluid dispenser 10 so that it can be removed through the mold opening 6.

[0054] Another embodiment is shown in Figure 7. In this embodiment, the bent actuator arm 71 operates to unfold or spread out the multilayer fluid dispenser 10. The bent actuator arm 71 is attached at the attachment point 72 at or near the lateral sides 19 and 19A of the multilayer film fluid dispenser 10. In this position, the bent actuator arms 71 are each bent outward from the tube 11. Before being introduced into the mold cavity 7, the bent actuator arm 71 and the multilayer film fluid dispenser 10 are retained in a sheath 74 to maintain the multilayer film fluid dispenser 10 in a folded or rolled position. The multilayer film fluid dispenser 10 passes through the mold opening 6 and enters the mold cavity 7 in the direction indicated by the arrow A. The sheath 74 is slidably mounted around the tube 11, the bent actuator arm 71 and the multilayer film fluid dispenser 10. As shown Figure 7B As shown, a sheath 74 that is larger than the mold opening 6 engages and is held by the mold side 4, thereby remaining outside the mold cavity 7. As the bent actuator arms 71 pass through the sheath 74 and the mold opening 6, their bends push the attachment points 72 laterally outward in the directions indicated by arrows C, respectively, thereby unfolding or spreading the multilayer film fluid dispenser 10 within the mold cavity 7. After the mold filling step is completed, the tube 11 and the multilayer film fluid dispenser 10 are removed from the mold cavity 7 by moving them in the direction indicated by arrows B. As the bent actuator arms 71 are removed through the sheath 74, the attachment points 72 are pushed inward, and the multilayer film fluid dispenser 10 is refolded or rewound so that it can be removed through the mold opening 6.

[0055] The construction material of the multilayer film fluid dispenser 10 is preferably an organic polymer. Examples of such organic polymers include homopolymers and copolymers of polyethylene. These include, for example, low density polyethylene, linear low density polyethylene, high density polyethylene, ultra-high molecular weight polyethylene, metallocene polyethylene, etc. Other useful organic polymers include polyesters, polypropylene, ethylene-propylene copolymers, oriented polyamides, polytetrafluoroethylene, various nylons, etc.

[0056] The flexible film substrates 10A and 10B may independently be single-layer or multi-layer structures. Figure 2-Figure 4 As illustrated, each of the flexible film substrates 10A and 10B is a two-layer construction. In such a two-layer construction, the inner layers 12A and 12B can be, for example, a heat-sealable organic polymer such as polyethylene; in such an embodiment, the outer layers 11A and 11B can be, for example, another polyethylene or polyester such as poly(ethylene terephthalate). The multilayer flexible film substrates 10A and 10B can be manufactured, for example, in a film coextrusion process.

[0057] If desired, a separate adhesive layer may be provided between the flexible film substrates 10A and 10B to provide bonding therebetween, as further described in FIG. 10 (and accompanying text) of WO 2021 / 046019. Similarly, a bonding layer may be provided between the inner layer 12A and the outer layer 11A, and / or between the inner layer 12B and the outer layer 11B.

[0058] The multilayer film fluid dispenser can be produced by a flexible film substrate using a method such as described in any one of, for example, WO 2021 / 046019, U.S. Patent 7,147,597, U.S. Patent 8,231,029, U.S. Patent 8,348,509, U.S. Published Patent Applications 2017 / 0247156, 2015 / 0314928, and 2015 / 0314919. Preferably, the flexible film substrate is joined using a heat sealing method to produce a multilayer film fluid dispenser. Sealing conditions may include, for example, a sealing pressure of 0.1 bar to 10 bar gauge pressure (0.01 MPa to 1 MPa); a sealing temperature of 100 to 200° C. and a sealing time of 0.1 seconds to 2 seconds. Sealing pressure is applied to those portions of the flexible film substrate corresponding to the space between the conduits. No sealing pressure is applied to the area where the conduits are to be produced.

[0059] The multilayer film fluid dispenser preferably exhibits a flexural modulus of 100 MPa to 3000 MPa measured according to ASTM D790-17.

[0060] The multilayer film fluid dispenser preferably exhibits a maximum force tensile strength (ASTM D1708-18) of 0.1 kPa to 4 kPa, 0.1 kPa to 10 kPa, or 0.18 kPa to 8 kPa, and a maximum force elongation of no greater than 40%, preferably no greater than 30%.

[0061] The mold is any container into which the polymer foam precursor fluid is introduced and cured. The mold includes a mold cavity and at least one mold opening, and the surfaces of the mold cavity define the geometry (size and shape) of the polymerized molded foam. The mold can be held in a press that applies pressure to the mold surfaces at least during the curing step to keep the mold closed and / or control the amount of expansion achieved during the curing step.

[0062] In some embodiments, the mold forms all or part of the exposed surface of the finished product. Thus, the mold can be, for example, all or part of the shell of an insulated structure such as a refrigerator or freezer, a door or panel, or a cooler; a buoy, lifesaving device or other flotation device; an automotive part; or all or part of the shell of another hollow structure in which a polymer foam core is desired.

[0063] In other embodiments, only a portion of the mold forms all or part of the exposed surface of the finished product. An important example of such an embodiment is laminate manufacturing, in which the top and / or bottom surfaces of the mold form part of the finished product, laminated to one or both sides of the molded polymer foam. In this case, the mold is typically composed of a top plate and a bottom plate and mold sides, and the mold sides are separated and / or removable from at least one of the top plate and the bottom plate, so that the mold sides can be removed from the finished product while the top plate and / or the bottom plate are adhered to the polymer molded foam. In such embodiments, the mold opening is preferably located in one or more of the mold sides, and at least during the curing step, the top plate and the bottom plate are kept in the press as previously described.

[0064] The multilayer film fluid dispenser is introduced into the mold cavity through the mold opening. Because the mold opening is usually smaller than the multilayer film fluid dispenser in at least one dimension (usually the width), the multilayer film fluid dispenser is folded or rolled before insertion so that it fits through the mold opening. The manner of folding or rolling is not critical. The multilayer film fluid dispenser can be folded (even simply wrinkled) in a regular pattern or in any random pattern; it may or may not be wrinkled as part of the folding process.

[0065] Once introduced into the mold, the multilayer film fluid dispenser is unfolded or rolled out as previously described.

[0066] The polymer foam precursor fluid flows into the conduit inlet, then passes through the conduit of the unfolded or spread-out multilayer film fluid distributor, and flows out of the multiple outlets into the mold cavity. During this step, the conduit is expanded by the polymer foam precursor fluid and allowed to pass through the expanded conduit to reach the multiple outlets. The multilayer film fluid distributor can be retracted through the mold cavity during this mold filling step, as previously described with respect to FIG. 1.

[0067] The polymer foam precursor fluid is usually produced by introducing its various constituent components into a mixing head via one or more supply systems. The supply system may include various pipes, pumps, metering devices, storage devices, heating and / or cooling devices, operating systems (including computerized operating systems) that can be used or expected to deliver the corresponding components to the mixing head in the correct proportions and under suitable temperature and / or pressure conditions. The resulting polymer foam precursor fluid is then transferred to a multilayer film fluid dispenser via a suitable fluid delivery system (such as pipeline 11 in Figure 1).

[0068] Sufficient polymer foam precursor fluid is introduced in such a way that the mold cavity is filled after the polymer foam precursor fluid expands during the curing step. If desired, an amount of polymer foam precursor fluid in excess of that required to just fill the mold cavity (after expansion) may be introduced during this step. If the mold cavity is overfilled in this manner, the overfill may be 1% to 30%, i.e., the amount of polymer foam precursor fluid introduced is 1% to 30% greater than the amount required to minimally fill the mold after expansion.

[0069] After the mold cavity is filled, the multilayer film fluid dispenser is preferably removed from the mold cavity through the mold opening. This is done by refolding and / or rewinding the multilayer film fluid dispenser and pulling it out of the mold opening. Refolding or rewinding can be done in various ways.

[0070] In embodiments where the multilayer film fluid dispenser includes dead legs, fluid within such dead legs may be removed, thereby creating negative pressure that pulls the lateral edges of the multilayer film dispenser toward the center, causing it to refold or rewind.

[0071] In an embodiment such as that shown in FIG. 5 , the arm 36 can be pulled outward by the collar 41. When the arm 36 passes through the collar 41 outward, the pivot point 40 is pulled laterally inward toward the mold opening 6, thereby pulling the lateral edges 19 and 19A of the multilayer film fluid dispenser 10 inward and refolding or rewinding them. Similar refolding effects are seen in the embodiments shown in FIGS. 6 and 7 . In the embodiment of FIG. 6 , the spring 61 is pulled outward through the sheath 64, which then pulls the attachment point 62 and the lateral edges 19 and 19A of the multilayer film fluid dispenser 10 inward, and refolds or rewinds them. In the embodiment of FIG. 7 , the bent actuator arm is pulled outward through the sheath 74, again pulling the attachment points 72 and 72 'and the lateral sides 19 and 19A of the multilayer film fluid dispenser 10 inward to refold or rewind them.

[0072] In other embodiments, the tube 11 with the attached multilayer film fluid dispenser 10 is simply pulled through the mold opening 6 with sufficient force to deform the multilayer film fluid dispenser 10, folding or creasing it sufficiently to remove it from the mold cavity. The multilayer film fluid dispenser does not need to be refolded or rewound in the same manner as it was before being inserted into the mold cavity.

[0073] In the curing step, the polymer foam precursor fluid introduced into the mold cavity by the multilayer film fluid dispenser expands and forms a molded polymer foam that fills the mold cavity. The preferred isocyanate-based polymer foam precursor fluid described below generally begins to react, expand, and cure spontaneously when the polyisocyanate component contacts the other ingredients; therefore, curing can begin during the mold filling step. To this end, the operating flow rate and other conditions are generally selected so that the polymer foam precursor fluid remains in a flowable state until it has been discharged through the multiple outlets of the multilayer film fluid dispenser and entered the mold cavity.

[0074] Curing is continued until a dimensionally stable molded polymer foam is obtained. The foam is considered dimensionally stable if it does not collapse upon demoulding and does not subsequently expand by more than 10%, preferably by more than 5%.

[0075] The curing conditions are selected in conjunction with the particular polymer foam precursor fluid. Depending on the circumstances, the curing step may be conducted at temperatures as low as 0°C or as low as 20°C and as high as 100°C. For example, the preferred isocyanate-based polymer foam precursor fluid may be cured with or without the application of heat, the fluid typically exhibiting an exothermic temperature rise as it reacts and cures. Even in this case, it may be necessary to accelerate the cure or to drive the cure to completion by applying heat to the outer surface of the mold. For example, the mold surface may be heated to 50 to 150°C if desired for this purpose.

[0076] Prior to expansion of the polymer foam precursor fluid, the internal mold pressure may be below atmospheric pressure to slightly above atmospheric pressure. As the polymer foam precursor fluid expands, it may experience a pressure increase. Mechanical pressure is often applied to the primary mold surface to control unwanted expansion and to set product dimensions, particularly thickness. The mold cavity may be vented.

[0077] Demolding times may vary significantly, from 30 seconds to 10 minutes or more. Once the polymer foam precursor fluid has solidified sufficiently to render the molded polymer foam dimensionally stable, the molded polymer foam may be demolded. Demolding is performed by removing the molded polymer foam from some or all of the components that make up the mold, or when mechanical pressure is released while some or all of the mold surfaces retain the product. When producing certain products such as laminates, some mold surfaces may retain the molded polymer foam. Thus, for example, a mold side 4 (again, see FIG. 1 ) may be separated from the molded polymer foam while leaving the top mold surface 3 and / or the bottom mold surface 2 adhered to the molded polymer foam, thereby producing a laminate structure.

[0078] In producing such a laminated structure, the top and / or bottom mold surface is a facing material that retains the molded polymer foam. The top facing and / or bottom facing can be, for example, metal (which may have an applied coating), kraft paper or other paper, fiber reinforced paper, metal foil-paper composite layer, plastic sheet or film, etc. In the case where the facing is flexible (such as the case of paper, plastic sheet and film and metal foil), the laminate is sometimes referred to as an "insulating board". The term "laminate" is used herein to cover boards made with rigid facings (such as metal sheets) as well as "insulating boards". Each facing layer preferably has a thickness of up to 5 mm, preferably up to 2.5 mm or up to 1 mm.

[0079] The process of the present invention can and preferably does include various additional steps (and associated equipment) required to produce a product for a specific application. When manufacturing laminates, the facing layers can be cut to specific sizes and shapes before the process begins. The facing layers, especially metal facing layers, can be pre-treated to promote good adhesion to the polymer foam or otherwise facilitate board manufacturing. Examples of pre-treatment steps include unwinding, corona discharge treatment, forming, heating to process temperature, and applying an adhesion promoter layer.

[0080] Similarly, the process can, and preferably does, include one or more downstream steps, such as trimming the product, cooling the foam or laminate from the curing temperature, stacking the foam or laminate, and wrapping the foam or laminate or otherwise preparing them for shipping or storage.

[0081] Preferred polymer foam precursor fluids are isocyanate-based formulations comprising at least one polyisocyanate, at least one blowing agent, at least one catalyst for reacting the polyisocyanate with itself, with a chemical blowing agent and / or with alcohol groups, and optionally but preferably at least one polyol. The polymer foam precursor fluid is a liquid or a liquid / gas mixture (sometimes referred to as an "emulsion"); thus, at least one of its components is a liquid under operating conditions. A nucleating gas such as air, nitrogen, hydrogen or argon may be mixed into the polymer foam precursor fluid.

[0082] Suitable organic polyisocyanates for use in the present invention include aliphatic, cycloaliphatic, araliphatic or aromatic polyisocyanates, or combinations of any two or more thereof. This class may include, for example, alkylene diisocyanates, specifically those having 4 to 12 carbon atoms in the alkylene moiety, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene 1,4-diisocyanate, 2-methyl-pentamethylene 1,5-diisocyanate, 2-ethyl-2-butylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate, and preferably hexamethylene 1,6-diisocyanate; cycloaliphatic diisocyanates, Such as cyclohexane 1,3-diisocyanate and cyclohexane 1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanato-methylcyclohexane (isophorone diisocyanate), 2,4-hexahydrotoluene diisocyanate and 2,6-hexahydrotoluene diisocyanate and the corresponding isomer mixtures, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate and 2,4'-dicyclohexylmethane diisocyanate - dicyclohexylmethane diisocyanate and the corresponding isomer mixtures; aromatic aliphatic diisocyanates such as 1,4-diisocyanato ditolyl ester and diisocyanato ditolyl ester isomer mixtures, and preferably aromatic diisocyanates and polyisocyanates such as 2,4-diisocyanatotolyl ester and 2,6-diisocyanatotolyl ester and the corresponding isomer mixtures, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate and 2,2′-diphenylmethane diisocyanate. In some embodiments, the present invention relates to a kind of polyisocyanate, a kind of iso ... Specific examples are diisocyanates and / or polyisocyanates containing esters, ureas, biuret, allophanates, uretonimines, carbodiimides, isocyanurates, uretdiones and / or carbamates, which contain 33.6 to 15 wt %, preferably 31 to 21 wt % of isocyanate groups, based on the total weight of the modified polyisocyanate. The organic polyisocyanates can be used alone or in combination.

[0083] Preferred polymer foam precursor fluids typically include at least one polyol, i.e., a compound having two or more hydroxyl groups. A variety of polyols may be used, depending in part on the desired properties of the polymer foam. Useful polyols therefore include polyether polyols, polyester polyols, hydroxyl-terminated polybutadiene rubbers, polyacrylate polyols, and polycarbonate polyols, among other types. Useful polyols have a hydroxyl equivalent weight of about 30 to 3000; however, for laminate production, it is preferred to use at least one polyol having a hydroxyl equivalent weight of 30 to 1000, especially 125 to 560. The polyol may have a hydroxyl functionality of 2 to 8 or more hydroxyl groups per molecule.

[0084] Useful polyether polyols include ethoxylates and / or propoxylates of one or more hydroxyl and / or amine group-containing starters having an equivalent weight of 30 to 59, including, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, trimethylolethane, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,2,6-hexanetriol, monoethanolamine, diethanolamine, triethanolamine, pentaerythritol, erythritol, sorbitol, sucrose, mannitol, N,N,N',N'-tetrakis(2-hydroxypropyl)-ethylenediamine, diethyltoluenediamine, dimethylthiotoluenediamine, and one or more of their combinations.

[0085] Available polyester polyols can be, for example, organic dicarboxylic acids (or corresponding anhydrides or esters) having about 2 to about 12 carbon atoms and polyols, preferably diols and / or triols having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms. Examples of suitable dicarboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, and preferably phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acids. Dicarboxylic acids can be used alone or in combination with each other. Examples of diols and polyols for preparing polyester polyols are ethylene glycol, diethylene glycol, 1,2- and 1,3-propylene glycol, dipropylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerine, trimethylolpropane. Also useful are modified aromatic polyester polyols, such as described in US Pat. No. 6,359,022, which contain one or more pendant aliphatic hydrocarbon groups having 6 or more carbon atoms in a straight or branched chain.

[0086] Furthermore, polyester polyols made from lactones such as ε-caprolactone or hydroxycarboxylic acids, such as ω-hydroxycaproic acid and hydrobenzoic acid, may also be used. Hybrid polyether-polyester polyols such as those described, for example, in WO 2011 / 137011 are also useful.

[0087] Other useful polyols include compounds having 2 to 8 hydroxyl groups, equivalent weights up to 125 and molecular weights up to 200, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, trimethylolethane, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,2,6-hexanetriol, mannitol, sucrose and sorbitol.

[0088] The polymer foam precursor fluid contains at least one blowing agent, which can be of the physical (endothermic) or chemical (exothermic) type, or both. Physical blowing agents are one or more compounds having a boiling point (at 1 atmosphere) of 10°C to 80°C, preferably 10°C to 50°C and containing no hydroxyl, primary and / or secondary amines, thiols, carboxyl groups or other groups reactive with isocyanate groups under the curing reaction conditions other than halogen groups. Useful physical blowing agents include hydrocarbons, hydrofluorocarbons, hydrochlorocarbons, hydrofluorochlorocarbons, ethers, etc. having the above-mentioned boiling points. C4-C6 hydrocarbons, such as any isomers (or mixtures of isomers) of butane, pentane and hexane are particularly useful. Also useful are hydrofluoroolefins and hydrofluorochloroolefins, such as described, for example, in US2007 / 0100010. Specific examples are trifluoropropylene, 1,3,3,3-tetrafluoropropylene (1234ze), 1,1,3,3-tetrafluoropropylene, 2,2,3,3-tetrafluoropropylene (1234yf), 1,2,3,3,3-pentafluoropropylene (1225ye), 1,1,1-trifluoropropylene, 1,1,1,3,3-pentafluoropropylene (1225zc), 1,1,2,3,3-pentafluoropropylene (1225yc), (Z)-1,1,1,2,3-pentafluoropropylene (1225yez), 1-chloro-3,3,3-trifluoropropylene (1233zd) and 1,1,1,4,4,4-hexafluorobut-2-ene (1336mzzm). Any mixture of two or more physical blowing agents may be used.

[0089] The physical blowing agent may be present, for example, in an amount of at least 12 parts by weight per 100 parts by weight of the polyol. The amount of the physical blowing agent may be, for example, at least 12, at least 14, or at least 15 parts by weight, and again, may be, for example, up to 25 parts, up to 22 parts, up to 20 parts, or up to 18 parts by weight.

[0090] A particularly suitable chemical blowing agent is water which, when present, reacts to produce carbon dioxide.

[0091] Suitable catalysts include urethane catalysts, i.e., catalysts for the reaction of alcohol groups and / or water with isocyanate groups, isocyanate trimerization catalysts, and carbodiimide catalysts. Suitable urethane catalysts are tin (II) and tin (IV) catalysts, catalysts containing other Group III to Group XV metals; tertiary amine compounds, amidines, tertiary phosphines, and the like. Useful isocyanate trimerization catalysts include strong bases such as alkali metal phenolates, alkali metal alkoxides, alkali metal carboxylates, quaternary ammonium salts, and the like. Useful carbodiimide catalysts include phospholene oxides, such as 3-methyl-1-phenyl-2-phospholene oxide (MPPO), 3-methyl-1-ethyl-2-phospholene oxide (MEPO), 3,4-dimethyl-1-phenyl-3-phospholene oxide, 3,4-dimethyl-1-ethyl-3-phospholene oxide, 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2-phospholene-1-oxide and their 3-phospholene isomers.

[0092] The polymer foam precursor fluid may also include various optional ingredients. Foam stabilizing surfactants are a useful optional ingredient. Suitable surfactants include, but are not limited to, silicones, such as silicone oils and organosilicone-polyether copolymers, including polydimethylsiloxane and polydimethylsiloxane-polyalkylene oxide block copolymers. Other suitable surfactants include organic surfactants, such as nonylphenol ethoxylates and ethylene oxide / butylene oxide block copolymers.

[0093] Another optional ingredient is a flame retardant, such as phosphorus-containing flame retardants, halogenated flame retardants, and melamine.

[0094] In addition to the aforementioned components, the polymer foam precursor fluid may also contain one or more fillers and / or reinforcing agents, such as glass fibers, carbon fibers, flaky glass, mica, talc, melamine and calcium carbonate; one or more pigments and / or colorants, such as titanium dioxide, iron oxide, chromium oxide, azo / diazo dyes, phthalocyanines, dioxazines and carbon black; one or more biocides; one or more preservatives; one or more antioxidants; one or more flame retardants; and the like.

[0095] The foam layer of the laminate produced according to the invention may have a foaming capacity of, for example, 20 kg / m 3 Up to 120kg / m 3 or 30kg / m 3 Up to 80kg / m 3 The foam density of 100 Å, as measured according to ASTM 1622-88. The cells may be at least about 70% closed, at least about 80% closed, or at least about 85% closed.

[0096] Laminated panels made according to the present invention can be used in the same manner and for the same purposes as laminated panels made using conventional processes. These panels can be used as thermal insulation materials for buildings, vehicles, sidewalks, and other structures. These panels can be used as lightweight decorative panels for building exterior walls, interior wall partitions, and other uses.

[0097] The laminates made according to the present invention can be used in industrial and residential applications. Uses include, for example, cold room insulation, doors, windows and sliding shutters. Even when thermal insulation properties are not required, the laminates can be used as building or decorative panels. For example, the laminates can be used to construct building exterior walls.

Claims

1. A method for producing a molded polymer foam, the method comprising: a) introducing a folded or rolled multilayer film fluid dispenser into a mold cavity through a mold opening, wherein the multilayer film fluid dispenser comprises (i) at least one first flexible film substrate layer and (ii) at least one second flexible film substrate layer, wherein the first flexible film substrate layer is bonded to the second flexible film substrate layer to form a multi-layer film member; as well as (iii) at least one conduit in fluid communication with at least one inlet and a plurality of outlets, the at least one conduit being disposed between the first flexible membrane substrate layer and the second flexible membrane substrate layer and forming one or more pathways for fluid to pass from the at least one inlet of the conduit through the multilayer membrane member to the plurality of outlets of the conduit; b) unfolding or spreading the multilayer film fluid dispenser inside the mold; as well as c) flowing a polymer foam precursor fluid into the at least one inlet, through the at least one conduit of the unfolded or spread multilayer film fluid distributor, and out of the plurality of outlets into the mold cavity; And then a curing step is performed by curing the polymer foam precursor fluid introduced into the mold cavity through the multilayer film fluid dispenser to produce a molded polymer foam in the mold cavity.

2. The method according to claim 1, further comprising, after step c) and before the curing step, step d) of refolding or rewinding the multilayer flexible film substrate layer, and step e) of removing the refolded or rewinded multilayer flexible film substrate layer through the mold opening.

3. The method according to claim 1 or 2, further comprising a demoulding step after the curing step.

4. A method according to any preceding claim, wherein the mold includes a bottom surface member, an opposing top surface member, and one or more mold frame members defining sides of the mold, the bottom surface member, top surface member and one or more mold frame members defining a cavity of the mold.

5. The method of claim 4, wherein in the demolding step, the one or more frame members are separated from the molded polyurethane foam, and the bottom surface member and the top surface member remain adhered to opposite sides of the molded polyurethane foam to form a laminate.

6. A method according to any preceding claim, wherein the multilayer film fluid distributor comprises one or more blind tubes connected to an inlet fluid and having no associated outlet, and wherein in step b), the multilayer film fluid distributor is unfolded or spread out by pumping a polymer foam precursor fluid and / or a separate expansion fluid into the blind tubes to expand the blind tubes.

7. A method according to any one of claims 1 to 5, wherein an arm is pivotally attached to relative lateral sides of the multilayer film fluid dispenser and is further pivotally mounted at an attachment point in a fixed position in an upstream direction of the multilayer film fluid dispenser 10, and wherein in step b), the arm extends outward in a lateral direction to unfold or spread out the multilayer film fluid dispenser.

8. A method according to any one of claims 1 to 5, wherein a spring is attached to the opposite lateral side of the multilayer film fluid dispenser and is attached at an attachment point 62 at a fixed position in the upstream direction of the multilayer film fluid dispenser, and wherein in step b), the spring extends outward in the lateral direction to unfold or spread out the multilayer film fluid dispenser.

9. A method according to any of the preceding claims, wherein before starting the flow of the polymer foam precursor fluid in step c), the unfolded or spread multilayer film fluid dispenser 10 is inserted into at least 50% of the length L of the mold cavity, and during step c), the unfolded or spread multilayer film fluid dispenser is gradually withdrawn toward the mold opening, while the polymer foam precursor is continuously or intermittently dispensed from the multiple outlets and into the mold cavity.

10. A method according to any preceding claim which is a discontinuous lamination process.

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