Foam material with thermal insulation, flame retardancy and EMI shielding

Abstract

The invention relates to a method and an article produced by injection molding. More particularly, a method and article of manufacture produced by injection molding that provides a component having one or more locations with reduced density wherein the component competes in mechanical properties with components otherwise produced from metallic material, such as vehicle components, and provides thermal insulation, flame retardancy and EMI shielding.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 380,867 (filing date October 25, 2022), which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to a method and article produced by injection molding. More particularly, the present invention relates to a method and article produced by injection molding that provides a component having one or more locations of reduced density, wherein the component is competitive in mechanical performance properties with vehicle structural components otherwise produced from metallic materials, and the component provides thermal insulation, flame retardancy, and electromagnetic interference (EMI) shielding. Background Art

[0004] Core back injection molding has been reported, wherein a molten polymer resin including a blowing agent is injected into a mold, and then the mold is opened or the core is removed to increase the mold cavity size and facilitate foaming and density reduction. However, there remains a need in the art for a foamed or relatively light weight part that also provides rigidity and strength to expand the use of these parts in, for example, vehicle structural or trim applications, and that also has improved fire resistance.

[0005] In particular, relatively light-weight components can be manufactured which are comparable to metal-based vehicle (trim) components in terms of mechanical property characteristics (eg load-bearing capacity) and have better performance in fire tests. Summary of the invention

[0006] A method of forming an injection molded part comprises:

[0007] providing an injection mold including a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity includes one or more locations having an initial spacing of at least 2.0 mm;

[0008] injecting a polymer composition including a flame retardant into the mold cavity, the polymer composition including a blowing agent;

[0009] increasing the initial mold cavity spacing at the one or more locations by at least 2.0 mm; and

[0010] An injection molded part is formed from a polymer component in the mold cavity, wherein the injection molded part includes a porous structure.

[0011] A method of forming an injection molded part comprises:

[0012] providing an injection mold including a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity includes one or more locations having an initial spacing;

[0013] providing one or more movable mold inserts, wherein the inserts are selectively retractable to increase the initial mold cavity spacing;

[0014] injecting a polymer composition including a flame retardant into the mold cavity, the polymer composition including a blowing agent;

[0015] At least one of the mold inserts is selectively retracted to increase the initial mold cavity spacing at a first location in the mold and maintain the initial mold spacing at a second location in the mold.

[0016] A method of forming an injection molded part comprises:

[0017] providing an injection mold including a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity includes one or more locations having an initial spacing;

[0018] Injecting a polymer component including an intumescent flame retardant into a mold cavity, the polymer component including: (a) a first polymer having a melt strength greater than or equal to 20.0 cn and a melt extensibility greater than or equal to 100 mm / sec; (b) a second thermoplastic polymer having a melt flow index greater than or equal to 10.0 g / 10.0 min; (c) reinforcing fibers; (d) a foaming agent;

[0019] increasing the initial mold cavity spacing at the one or more locations; and

[0020] An injection molded part is formed from a polymer component in the mold cavity, wherein the injection molded part includes a porous structure.

[0021] A method for forming an injection molded part comprises: providing an injection mold comprising a first mold half and a second mold half, the second mold half comprising a first side and a second side remote from the first side, the first side having a location for injecting a polymer component, the mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity comprises one or more locations having an initial spacing of at least 2.0 mm. Then, positioning a metal sheet or a metal mesh in the mold, then injecting a polymer component comprising a flame retardant into the mold cavity, the polymer component comprising a foaming agent, then increasing the initial mold cavity spacing by at least 2.0 mm at one or more locations, and forming an injection molded part in the mold cavity from the polymer component, wherein the injection molded part comprises a porous structure and a corresponding first side proximal to the location for injecting resin and a second side remote from the location for injecting plastic resin. A majority of the metal sheet or metal mesh is positioned more toward the second side of the part remote from the location for injecting the polymer component than the first side of the part.

[0022] A method for forming an injection molded part comprises: providing an injection mold comprising a first mold half and a second mold half, the second mold half comprising a first side and a second side remote from the first side, the first side having a location for injecting a polymer component, the mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity comprises one or more locations having an initial spacing of at least 2.0 mm. Then, positioning a composite polymer sheet in the mold, the composite polymer sheet configured to provide EMI shielding, injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a foaming agent; and increasing the initial spacing of the mold cavity by at least 2.0 mm at the one or more locations. Then, forming an injection molded part from the polymer component in the mold cavity, wherein the injection molded part comprises a porous structure and a corresponding first side proximal to the location for injecting resin and a second side remote from the location for injecting plastic resin. A majority of the composite polymer sheet providing EMI shielding is positioned more toward the second side of the part remote from the location for injecting the polymer component (compared to the first side of the part). BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other features of the present invention and the manner of implementing them will be more clearly and better understood by referring to the following description of embodiments in conjunction with the accompanying drawings, in which:

[0024] Figure 1 is a perspective view of an article according to the present invention comprising an injection molded part;

[0025] Figure 2 yes Figure 1 The injection molded parts along Figure 1 A cross-sectional view taken along line 2-2;

[0026] Figure 3A is an enlarged cross-sectional view of the injection mold herein, wherein the mold comprises two mold halves, with a movable insert in one mold half being in an extended position to determine an initial cavity spacing.

[0027] Figure 3B yes Figure 2 An enlarged cross-sectional view of the injection molded part within circle 3 while the injection molded part is in the injection mold;

[0028] Figure 3C yes Figure 2 An enlarged cross-sectional view of an injection molded part within circle 3 while the injection molded part is in an alternative injection mold;

[0029] Figure 3D is another cross-sectional view of an injection molded part showing a selected area without density reduction;

[0030] Figure 4 3 is a cross-sectional view of the injection molded component combined with the liner component and the decorative cover component of the article;

[0031] Figure 5 is a partial plan view of another embodiment of an injection molded component as a load base;

[0032] Figure 6 yes Figure 5 The injection molded parts along Figure 5 A partial cross-sectional view taken along line 6-6;

[0033] Figure 7 yes Figure 5 The injection molded parts along Figure 5 A partial cross-sectional view taken along line 7-7 of ; and

[0034] Figure 8 Cross-sectional views of components "A", "B", "C" and "D" herein are provided wherein the initial die spacing is increased by retraction of the movable insert to provide a reduced density and porous form. DETAILED DESCRIPTION

[0035] It is to be understood that the application of the present invention is not limited to the details of the construction and arrangement of the components set forth in the following description or shown in the accompanying drawings. The present invention is capable of other embodiments and can be practiced or carried out in various ways. Also, it is to be understood that the words and terms used herein are for illustrative purposes and should not be considered limiting, as will be understood by those skilled in the art.

[0036] refer to Figure 1-2, an article 10 according to the present invention may include an injection molded part 12, which injection molded part 12 may form a substrate for the article 10. In certain embodiments, the article 10 may be a load floor of a cargo area of ​​a vehicle, it may be a cover / lid for a storage compartment that may hold a spare tire. In other embodiments, the article 10 may be a seat pan, such as a seat pan for a folding row seat. In other embodiments, the article 10 may be a seat back for a seat, or a parcel shelf for a hatch back. In other embodiments, the article 10 may be a battery housing for an electric vehicle.

[0037] refer to Figure 3A , the molding apparatus 100 includes a mold 110 including a first mold half 112 and a second mold half 114 separated at a parting line 116. A movable insert is indicated at 140, which is arranged in an extended position relative to a mold base 150 so as to determine an initial spacing 117 in the mold cavity. At 202 is indicated an injection unit 202 of the injection molding machine 200.

[0038] refer to Figure 3B , an injection molded part 12 according to the present invention can be formed in a molding device 100. The first mold half 112 and the second mold half 114 can be closed together, with the movable insert retracted at this time, so as to define a mold cavity 118 between the first mold half molding surface 122 and the second mold half molding surface 124, in which the injection molded part 12 will be formed.

[0039] As shown, the first mold half 112 can be understood as the gate side core or (polymer component) injection half of the mold set 100, and the second mold half 114 can be understood as the ejection side core or ejection half of the mold set 100. In some embodiments, the second mold half 114 can be understood as forming the outer (e.g., Class A) side / surface of the injection molded part 12 when molded (which faces the vehicle occupant), while the first mold half 112 can be understood as forming the inner (e.g., Class B) side / surface of the injection molded part 12 (which faces the vehicle body structure). In other embodiments, the foregoing can be reversed, that is, the first mold half 112 can be understood as forming the outer surface of the injection molded part 12 when molded (which faces the vehicle occupant), while the second mold half 114 can be understood as forming the inner surface of the injection molded part 12.

[0040] The injection molded part 12 may be formed by delivering molten polymer components from the injection unit 202 of the injection molding machine 200 through the runners 130 of the first mold half 112 and / or the second mold half 114 to the mold cavity 118 .

[0041] The injection molded part 12 may preferably be formed from a polymeric component having a flexural modulus (measured in accordance with ASTM D-790-10) of at least 150,000 psi at room temperature (23° C.) to provide sufficient rigidity, particularly for use as a substrate, to support the article 10. More particularly, the polymeric resin component used to form the injection molded part 12 may preferably have a reported flexural modulus (measured in accordance with ASTM D-790-10) at 23° C. in the range of 150,000-1,500,000 psi, more preferably 300,000 psi to 1,000,000 psi.

[0042] In addition to providing sufficient rigidity for the substrate of the article 10, the composition used for the injection molded part 12 is preferably one that provides suitable load bearing capacity versus temperature characteristics. Thus, the injection molded part 12 can be formed from a polymer composition having a reported heat distortion temperature of at least 75° C. at 264 psi (measured in accordance with ASTM D-648-07). More particularly, the injection molded part 12 can have a heat distortion temperature in the range of 75-300° C. at 264 psi (measured in accordance with ASTM D-648-07), more preferably in the range of 150-300° C.

[0043] The polymer component of the injection molded part 12 more preferably comprises a thermoplastic polymer component, which may include, consist essentially of, or consist of one or more polymers, such as polyethylene (PE), polypropylene (PP), polyurethane (PU), polyisoprene (synthetic or natural rubber), acrylonitrile-butadiene-styrene (ABS), aromatic-based polyesters such as PET, polycarbonate (PC), polyamide (PA), polyphenylene oxide (PPO), polyamide-imide, polyetherimide (e.g., ULTEM), polyurethane (PU), polyisoprene (synthetic or natural rubber), acrylonitrile-butadiene-styrene (ABS), aromatic-based polyesters such as PET, polycarbonate (PC), polyamide (PA), polyphenylene oxide (PPO), polyamide-imide, polyetherimide (e.g., ULTEM), polyisoprene (PU), polyisoprene (ABS), polyisoprene (PU), polyisoprene (PE), polyisoprene (PP ... TM ), thermotropic liquid crystal polyesters (such as XYDAR TM ) and aromatic polyketones, for example sold under the trade name VICTREX TM Polyetheretherketone (PEEK) sold as ABS, or blends thereof. A particularly preferred blend includes polycarbonate / ABS.

[0044] In order to increase the flexural modulus of the injection molded part and thus increase the rigidity or load-bearing capacity, the thermoplastic polymer of the polymer component may preferably be reinforced with reinforcing additives or fillers (e.g. reinforcing fibers and / or mineral reinforcing agents). The mineral reinforcing agent may include, for example, silicon dioxide, calcium oxide or aluminum oxide. The reinforcing fibers may preferably include glass fibers, cellulose fibers, aramid fibers or carbon fibers. The reinforcing additives or fillers may preferably be present in the range of up to 60.0% (wt), more preferably in the range of 10.0% (wt) to 40.0% (wt).

[0045] The preferred length of the reinforcing fibers may depend to some extent on the type of injection unit 202 of the injection molding machine 200, such as the plunger, reciprocating screw, and mold (hot runner) design. Therefore, the length of the reinforcing fibers may preferably be in the range of 0.25 mm to 13.0 mm, and even more preferably in the range of 2.0 mm to 6.0 mm.

[0046] In addition, the polymer component used for the injection molded part 12 includes a foaming agent. The foaming agent may include a physical foaming agent, which refers to a compound that is metered into the polymer melt and promotes foaming without significant chemical changes. Therefore, the physical foaming agent preferably includes hydrocarbons (such as isobutane, cyclopentane and isopentane), carbon dioxide, nitrogen and chlorofluorocarbons. The foaming agent may also include one or more chemical foaming agents (CFA), which decompose in the injection molding process to produce gas so that the injection molded part 12 is formed with a porous (foamed) structure. In this way, by using a physical foaming agent or a chemical foaming agent, the density and weight of the injection molded part 12 can be reduced.

[0047] Chemical blowing agents can be endothermic, exothermic, or a combination (mixture) thereof, and can be mixed with the carrier prior to introduction into the injection molding process. Example chemical blowing agents can include azodicarbonamide, azodicarbonamide, azobisisobutyronitrile, sodium borohydride, and sodium bicarbonate / citric acid, which react to form sodium citrate, carbon dioxide, and water. Blowing agents can also include alkaline earth metal carbonates and acids, such as disclosed in U.S. Patent Application Publication No. 2011 / 0263734 entitled "Blowing Agents Formed From Nanoparticles of Carbonates", which is incorporated herein by reference in its entirety. The blowing agent can preferably be present in the polymer component at a preferred level of up to 10.0% (wt), or in the range of 0.1% (wt) to 10.0% (wt), or more preferably in the range of 2.0% (wt) to 8.0% (wt), or in the range of 4.0% (wt) to 6.0% (wt). Particularly preferred blowing agents herein include endothermic chemical blowing agents which generate gas volumes in the range of 20 cc / g to 100 cc / g, more preferably 20 cc / g to 50 cc / g, even more preferably 30 cc / g to 40 cc / g.

[0048] During processing, the blowing agent may be understood to promote the formation of a suitable cell structure in the injection molded part 12. The blowing agent (whether physical or chemical) preferably reduces the molded density by up to a range of 80.0% compared to an injection molded part 12 produced from the same polymer composition (wherein the injection molded part 12 is substantially solid, i.e., has relatively little to no cellular structure).

[0049] Expanding on the above, as described more fully herein, depending on the operation of the mold, particularly the ability to selectively control the expansion of the mold cavity at one or more selected locations by retracting one or more movable inserts 140, corresponding selected locations of the molded part can be configured to receive a specific targeted density reduction, a value greater than 0% up to 80.0%, or even no density reduction. Density reduction should be understood as a relatively lower density compared to the density of a similar molded part without the use of a foaming agent and without the retraction and increase in size of the mold cavity.

[0050] It is further contemplated herein that the molded part can now be produced with a relatively small amount or no density reduction at one or more locations in the mold cavity, which density reduction can be understood as a density reduction of 0% to 10.0%, more preferably 0% to 5.0%, or even more preferably 0% to 2.5% or 0% to 1.0%. Therefore, it can now be understood that in the present invention, the molded part can be produced with a density reduction in the range of, for example, 0% to 10.0% at one or more locations in the mold cavity, and one or more other locations of the mold cavity can provide a portion with a density reduction greater than 10.0% to 80.0%.

[0051] As yet another example, when formed in a mold cavity, a molded part may have a location with a density reduction of 0-10%, another location with a density reduction of greater than 10.0.0% to 15.0%, another location with a density reduction of greater than 15.0% to 20.0%, another location may have a density reduction of greater than 20.0% to 25.0%, another location may have a density reduction of greater than 25.0% to 30.0%, another location may have a density reduction of greater than 30.0% to 35.0%, another location may have a density reduction of greater than 35.0% to 40.0%, another location may have a density reduction of greater than 40.0% to 45.0%, and another location may have a density reduction of greater than 50.0% to 55.0%. Another location may have a density reduction of greater than 45.0% to 50.0%, another location may have a density reduction of greater than 45.0% to 50.0%, another location may have a density reduction of greater than 50.0% to 55.0%, another location may have a density reduction of greater than 55.0% to 60.0%, another location may have a density reduction of greater than 60.0% to 65.0%, another location may have a density reduction of greater than 65.0% to 70.0%, another location may have a density reduction of greater than 70.0% to 75.0%, and another location may have a density reduction of greater than 75.0% to 80.0%.

[0052] More generally, it should also be understood that the molded parts herein can have a density reduction at one location in the mold cavity that is the same or different from the density reduction at another location. For example, it is noted that the range of density reduction is 0% to 80.0%. Therefore, it is contemplated that any value within the range can be selected to cause such a density reduction at one location in the mold, and another value within the range can be selected to cause a density reduction at another location in the mold, wherein these values ​​are the same or different. Density reductions can also be selected for a third location in the mold, a fourth location, and so on, up to the tenth location in the mold. Therefore, it is contemplated herein that a density reduction within the range of 0-80.0% can be selected, and the mold is configured to achieve any such selected density reduction within the range of 0-80.0% at up to ten different locations in the mold cavity.

[0053] Alternatively, as described more fully herein, the entire part can have a selected density reduction having a value greater than 0% up to 80%. For example, a density reduction of 10%, 20%, 30%, 40%, 50%, 60%, 70% and 80%.

[0054] In the injection molding process, the first half mold 112 and the second half mold 114 are initially set to be completely closed, at which time the first half mold molding surface 122 and the second half mold molding surface 124 can be exposed to each other, and in a particularly preferred example, are initially spaced apart from each other by a distance of at least 4.0 mm, and preferably in the range of 4.0 mm to 10.0 mm. Figure 3A . Thus, this spacing can correspond to the longest initial cross-sectional dimension of a given part to be molded. More typically, the initial spacing in the mold cavity can include one or more portions of the cavity having a spacing of at least 2.0 mm, 3.0 mm, 4.0 mm, 5.0 mm, 6.0 mm, 7.0 mm, 8.0 mm, 9.0 mm, or 10.0 mm. Thus, the initial spacing in the mold cavity can fall within the range of 2.0 mm to 10.0 mm, or 3.0 mm to 10.0 mm, or 4.0 mm to 10.0 mm, or 5.0 mm to 10.0 mm, or 6.0 mm to 10.0 mm, or 7.0 mm to 10.0 mm, or 8.0 mm to 10.0 mm, or 9.0 mm to 10.0 mm.

[0055] Additionally, it should be understood that, depending on the geometry of a given component, the initial spacing in the mold can be set to be substantially uniform throughout the mold cavity (i.e., between all opposing mold surfaces defining the cavity). For example, the initial spacing in the cross-section of the mold cavity does not vary by more than + / - 10.0%.

[0056] As described, the movable insert is shown at 140 of the second mold half 114, which can be arranged relative to the mold base 150 ( Figure 3A ) in an extended position, the movable insert 140 is received and supported in the mold base 150 for movement. Therefore, it can now be understood that the movable insert can be configured to determine an initial spacing at one or more locations in the mold cavity, which initial spacing can fall within the range of 2.0mm to 10.0mm, or 3.0mm to 10.0mm, 4.0mm to 10.0mm, or 5.0mm to 10.0mm, or 6.0mm to 10.0mm, or 7.0mm to 10.0mm, or 8.0mm to 10.0mm, or 9.0mm to 10.0mm, as described above.

[0057] The molten polymer component can then be delivered from the injection unit 202 of the injection molding machine 200 to the mold cavity 118 through the runner 130 of the first mold half 112 (which runner 130 can optionally be a hot runner) so that the molten polymer component completely fills the mold cavity 118. As the molten polymer component is delivered through the injection nozzle of the injection molding machine and the runner 130 of the first mold half 112, the blowing agent can begin to provide gas and form a porous structure in the polymer component. Optionally, the mold cavity 118 can be pressurized with a back pressure, which inhibits or otherwise prevents the formation of a porous structure until after the injection / firing is complete and all of the polymer components used to form the injection molded part 12 are introduced into the mold cavity 118. The porous structure herein refers to the polymer component having a characteristic of having regions of polymer material and regions without polymer material when solidified, which regions can include gas generated by the blowing agent, or even air.

[0058] Once the mold cavity 118 begins to fill or is completely filled with the molten polymer component, the movable insert 140 of the second mold half 114 can be preferably retracted at least 2.0 mm relative to the mold base 150 to a retracted position, or more preferably within a range of 2.0 mm to 40.0 mm, such as Figure 3B Thus, the retraction amount can be at least 2.0mm, 3.0mm, 4.0mm, 5.0mm, 6.0mm, 7.0mm, 8.0mm, 9.0mm, 10.0mm, 11.0mm, 12.0mm, 13.0mm, 14.0mm, 15.0mm, 16.0mm, 17.0mm, 18.0mm, 19.0mm, 20.0mm, 21.0mm, 22.0mm, 23.0mm, 24.0mm, 25.0mm, 26.0mm, 27.0mm, 28.0mm, 29.0mm, 30.0mm, 31.0mm, 32.0mm, 33.0mm, 34.0mm, 35.0mm, 36.0mm, 37.0mm, 38.0mm, 39.0mm, and 40.0mm. Therefore, it can be understood that when the movable insert is in the extended position ( Figure 3A ) and retracted position ( Figure 3B ), preferably, the two mold halves 112, 114 do not separate at the parting line 116.

[0059] As another example, where the initial mold cavity opening defines one or more positions with an initial spacing of at least 2.0 mm, the movable insert can be retracted 2.0 mm to 40.0 mm so that the mold cavity includes one or more positions with a spacing of 4.0 mm to 44.0 mm between the opposing mold surfaces of the two mold halves. In addition, where the initial mold cavity opening defines one or more positions with an initial spacing of 10.0 mm, the movable insert can be retracted further 2.0 mm to 40.0 mm so that the mold cavity again includes one or more positions with a spacing of 12.0 mm to 50.0 mm.

[0060] As yet another non-limiting example, the mold cavity may be configured so that it provides a substantially uniform initial spacing of 2.0 mm throughout the mold cavity, and the movable insert may be retracted 2.0 mm to 40.0 mm to provide a substantially uniform spacing of 4.0 mm to 44.0 mm between the mold surfaces throughout the mold cavity. Additionally, when the mold cavity provides a uniform initial spacing of 10.0 mm throughout the mold cavity, the movable insert may be retracted 2.0 mm to 40.0 mm to provide an increased spacing in the mold and substantially uniformly between 12.0 mm and 50.0 mm throughout the mold cavity.

[0061] In some embodiments, the movable insert 140 can be part of an ejection mechanism of the second mold half 114. In this case, after cooling, the first mold half 112 and the second mold half 114 can be separated again at the parting line 116, and the movable insert is returned to the extended position, at which time the injection molded part 12 can be ejected from the second mold half 114.

[0062] like Figure 3C As shown and described above, the movable insert may be but is not limited to Figure 3A While a single insert is shown, the present invention contemplates the use of one or more movable mold inserts. Figure 3C As shown, the second mold half 114 has at least two movable mold inserts 142 and 144. The movable mold inserts 142, 144 can be moved in a similar manner to the movable insert 140. Moreover, it can be understood that multiple mold inserts (such as movable inserts 142, 144) can be moved independently or simultaneously. In other words, the movable inserts 142, 144 can move simultaneously or at different times relative to each other.

[0063] The movable mold inserts 142, 144 may also move for the same period of time or for different periods of time. The movable mold inserts 142, 144 may also move at the same speed and / or the same acceleration relative to each other, or at different speeds and / or accelerations. The movable mold inserts 142, 144 may also move the same distance or different distances relative to each other. The operation of the movable mold inserts 142, 144 may be controlled using a single electronic controller or multiple separate controllers. The movable mold inserts 142, 144 may be moved pneumatically (compressible gas, such as air) or hydraulically (relatively incompressible liquid, such as oil).

[0064] Thus, in the present invention, preferably, there may be 1-10 movable inserts that may be relied upon to increase or not increase the initial spacing of the mold cavity at one or more locations in the cavity. Thus, these movable inserts may provide substantially no density reduction, provide the same density reduction, or provide different density reductions at one or more locations in the mold.

[0065] Thus, the present invention can provide an injection molded part wherein the core layer 26 of the part has the same or different density reductions at different locations on a given part cross section. Thus, it will be appreciated by those skilled in the art that, for example, with a minimum of 2 inserts, one location of the part may have the same or different density in the core portion compared to another location. Furthermore, one location may have a relatively small density reduction (0-10.0%) and another location may have a relatively large density reduction (greater than 10.0% to 80.0%).

[0066] like Figure 3B and 3C As shown, in the cross section of the injection molded part 12, the injection molded part 12 may preferably be formed into a sandwich structure with different densities, wherein two opposite sides of the injection molded part 12 have two outer (skin) layers 22 and 24, which are respectively arranged on opposite sides of the middle (core) layer 26. The density of each of the outer (skin) layers 22, 24 is preferably greater than the density of the middle (core) layer 26. The outer skin layers 22, 24 may also have a varying thickness or a relatively uniform thickness (e.g., a thickness that varies by no more than + / -10.0%).

[0067] More particularly, the porous structure of the injection molded part 12 can be substantially present in the middle (core) layer 26, while a reduced level of porous structure is present in either of the two outer (skin) layers 22, 24. The outer (skin) layers 22, 24 can preferably have a thickness in the range of 0.25 mm to 2.0 mm, and a density in the range of 90% to 100% of the density of the polymer component without the porous structure. Therefore, it can be understood that the injection molded part herein can include an outer skin layer having a thickness in the range of 0.25 mm to 2.0 mm with a first density d1 and a core layer having a second density d2, wherein d1>d2.

[0068] Notice Figure 3D , another cross-sectional view of an injection molded component 12 that can be formed herein is shown, wherein preferably a plurality of independently movable inserts may be used, which are arranged to provide different density reductions at a plurality of locations in the mold. In particular, one or more independently movable inserts may be selectively retracted at one or more locations in the mold. There may be movable inserts at other locations in the mold that are not selectively retracted so as to maintain the provided initial mold spacing in any event.

[0069] Expanding on the above, the mold itself may be configured such that, at selected positions, no movable insert may be used and the mold halves, when closed, will similarly provide one or more initial mold spacings, wherein no retraction, necessarily, is required to maintain the initial mold spacing at such positions.

[0070] Therefore, it can be provided that, at one or more regions 25 where the initial spacing is maintained, there is no retraction, and the density reduction of the injected polymer component is relatively small to no density reduction (e.g., 0% to 10%, or 0% to 5.0%, or 0% to 2.5%, or 0% to 1.0%). At one or more regions with retraction, the density reduction produced by the injected polymer component can preferably fall within the range of greater than 10% to 80%.

[0071] Then, the skin layer 27 formed at the region 25 where the initial spacing is maintained may preferably be a relatively homogeneous uniform polymer material layer, preferably having a total thickness of 1.0 mm to 2.0 mm. Therefore, one skin layer 25A may preferably have a thickness in the range of 0.5 mm to 1.0 mm, and the other skin layer 25B may also preferably have a thickness in the range of 0.5 mm to 1.0 mm.

[0072] The skin layer at 27 may also be referred to as a kiss-off region in combination with one or more regions of reduced density 26 in the core layer. It will also be appreciated that one or more regions 25 with relatively little to no reduced density can be used to provide additional structure to increase load requirements and reduce the risk of shear failure in those regions 26 where there is foaming and reduced density.

[0073] refer to Figure 4 As a seat pan, the article 10 may include a cushion component 14 and a decorative cover component 16 in addition to the injection molded component 12. The cushion component 14 may be a foam cushion.

[0074] refer to Figure 5-7 As a load-bearing base, the article 10 (more particularly the injection molded part 12) may include an integral handle 50 formed as a single piece with the injection molded part 12. A handle hole 52 may be formed in the injection molded part 12 to better facilitate gripping the integral handle 50.

[0075] The article 10 (more particularly the injection molded part 12) may also include one or more hinges 58 that are reinforced with an in-mold (i.e., insert molded) reinforcement insert 66. As shown, the injection molded part 12 including the insert 66 may include a hinge pin hole 60 for the hinge pin. The article 10 (more particularly the injection molded part 12) may also include ribs 70 to increase rigidity.

[0076] The injection molded parts herein may also be integrated with other parts (e.g., other vehicle trim parts) and overmolded, in which case the parts formed herein effectively serve as a substrate which can then be partially or completely covered by overmolding of a second material during the manufacturing process.

[0077] As mentioned above, the polymer component of this article preferably includes a thermoplastic polymer, which also preferably includes reinforcing fibers. Even more preferably, it has been recognized that the polymer component of this article can include a selected amount of a first resin, which has the preferred characteristics of selected melt strength and melt ductility. Melt strength is understood herein as the force required to extend the extruded melt of the selected cross-sectional diameter of the selected rheometer to the breakpoint. Melt extensibility is the stretch ratio that the melt can withstand without breaking. Therefore, the preferred resin of this article includes a resin that provides relatively high melt strength and extensibility in the molten phase, such as used in the injection molding process of this article.

[0078] Preferably, relatively high melt strength resins herein mean melt strength greater than or equal to 20 centinewtons (20 cn), or more preferably in the range of 20.0 cn to 200.0 cn, 20.0 cn to 100.0 cn, or 20.0 cn to 50.0 cn. Melt extensibility is preferably equal to or greater than 100 mm / sec, or more preferably in the range of 100 mm / sec to 300 mm / sec, 100 mm / sec to 250 mm / sec, or 150 mm / sec to 250 mm / sec. The values ​​of melt strength and / or melt extensibility herein are conveniently generated using a Goettfert Rheograph 1000 or Rheograph 6000 three-hole capillary rheometer and a Goettfert Rhoetens 71.97 extensional rheometer.

[0079] Therefore, the polymer component of the present invention even more preferably comprises: (a) a first polymer having a melt strength greater than or equal to 20 cn (or more preferably 20 cn to 200.0 cn) and a melt extensibility equal to or greater than 100 mm / sec (or more preferably 100 mm / sec to 300 mm / sec), wherein the first polymer is preferably present at a level of 10.0% (wt) to 90.0% (wt), or 25.0% (wt) to 75.0% (wt), or 40.0% (wt) to 60.0% (wt), or 45.0% (wt) to 55.0% (wt); (b) a second thermoplastic polymer having a melt flow index greater than or equal to 10.0 g / 10.0 min, more preferably at 10.0 g / 1 0.0 minutes to 40.0 grams per 10 minutes, or 25.0 grams per 10.0 minutes to 35.0 grams per 10 minutes, wherein the second thermoplastic polymer is present at a level of 90.0% (wt) to 10.0% (wt); (c) reinforcing fibers, preferably present at a level of 10.0% (wt) to 40.0% (wt), or even more preferably 15.0% (wt) to 30.0% (wt); and (d) a blowing agent, more preferably present at a level of 0.1% (wt) to 10.0% (wt), the blowing agent generating a gas volume of at least 20cc / g, or more preferably 20cc / g to 100cc / g, and the blowing agent may preferably be present at a level of up to 10.0% (wt), or in the range of 0.1% (wt) to 10.0% (wt). These components are also preferably characterized by flexural rigidity and / or instrumented impact properties, as described more fully herein.

[0080] An example of a particularly preferred resin that provides the above-mentioned melt strength and melt elongation properties is a polypropylene resin, which is available under the trade name PP-UMS 561P The resin was confirmed to have a melt strength of greater than or equal to 65 cn.

[0081] It is now found that these components described above and as described more fully below are particularly suitable for the injection molding method of the present invention, wherein the components are injected into a mold cavity together with a blowing agent, the mold cavity having one or more locations with a preferred initial spacing in the range of 1.0 mm to 6.0 mm, and then the initial cavity spacing at the one or more locations is increased by 2.0 mm to 20.0 mm, and an injection molded part including a porous structure is formed.

[0082] As a representative and comparative working example, note below Figure 8 ,Should Figure 8 A cross-sectional view of a component herein is provided wherein the initial mold spacing is increased by retraction of a movable insert to provide a reduced density and porous form. More particularly, in Figure 8 In each of "A", "B", "C" and "D" shown, the initial cavity spacing was 4.0 mm, and the cavity spacing was increased to 8.0 mm. The skin thickness on samples "A", "B", "C" and "D" ranged from 1.0 mm to 1.5 mm.

[0083] As shown in "A" and "B", the polymer component includes a combination of 25.0% (wt) to 30.0% (wt) glass fibers, 5.0% (wt) chemical foaming agent (as described herein, the chemical foaming agent provides a gas volume in the range of 20 cc / gram to 100 cc / gram), and a balance, the balance comprising A 50:50 blend of PP-UMS 561P in combination with a polypropylene homopolymer having a melt flow index of 35 g / 10 min. Parts made using only a polypropylene homopolymer having a melt flow index of 35 g / 10 min and 20 wt% glass fiber and 4.0 wt% chemical blowing agent are shown for comparison purposes and at "C" and "D". Figure 8 It can be observed that samples "A" and "B" show relatively uniform microporous structures. Comparative samples "B" and "C" show relatively more fibrous foam cores, and the skin is relatively easy to separate from the core.

[0084] As described above, the parts manufactured herein using a combination of a relatively high melt strength polymer having a determined melt extensibility and a thermoplastic polymer having a melt flow index greater than or equal to 10 g / 10 minutes and reinforcing fibers and a blowing agent (the blowing agent produces a gas volume in the range of 20 cc / g to 100 cc / g) preferably provide bending stiffness and / or instrumented impact performance, making them particularly suitable for structural load-bearing vehicle trim parts. Regarding instrumented impact performance, it should be noted that the parts produced by the above components herein represent multi-axial impacts from 1.0 Joule total energy and 0.5 kN maximum load to 50.0 Joule total energy and 4.0 kN maximum load. More preferably, the parts represent multi-axial impacts from 15.0 Joule total energy to 50.0 Joule total energy and 2.0 kN maximum load to 4.0 kN maximum load. This instrumented impact is measured according to ISO-6603-2 (April 2019). One example of an instrumented impact testing device includes the Instron Dynatup 9250HV Multi-Axial Impact Tester.

[0085] Furthermore, the bending stiffness of the parts produced herein was determined, wherein the bending stiffness is a geometry-specific parameter and is therefore determined by the product of the elastic modulus x "second moment of area". The "second moment of area" is also called the moment of inertia of the shape. It is also considered to be a measure of the efficiency of the cross-sectional shape in resisting bending under load. For a given geometry, such as a plaque, the second moment of area "I" can be determined by the following equation; I = 1 / 12 x (width of the plaque) x thickness 3 The flexural stiffness (FR) of this geometry can then be determined by the following expression: FR = elastic modulus x second moment of area. Thus, for the above reference composition using the above polypropylene resin, which is preferably a relatively high melt strength resin, at a starting thickness in the range of 1.0 mm to 6.0 mm, expanded in the range of 2.0 mm to 20.0 mm, where the elastic modulus is specified to be approximately 1500 MPa, the flexural stiffness will fall within 0.500 mm. 2 Up to 150nm 2 within the range.

[0086] In addition to the above, it has now been discovered that the injection molded parts having a porous structure herein are preferably modified using a flame retardant (FR). In particular, the flame retardant maintains the ability of the resin to undergo the molding process described herein, which achieves a reduced density part with a relatively uniform microporous structure, and the flame retardant part still provides the characteristics of a structural vehicle part with more typical mechanical properties characteristic of metallic materials. Moreover, according to the injection molding process described herein, the flame retardants described herein enable them to avoid the use of halogenated based structures and provide the necessary flowability and handleability as well as a relatively uniform porous structure when the mold spacing is increased.

[0087] The preferred flame retardants herein are non-halogenated and also preferably belong to the category of intumescent flame retardants (IFRs), which can expand when exposed to heat and can form carbonaceous (carbon-based) char. Such IFRs typically comprise an acid source, a carbonaceous carbonizing agent, and a foaming agent. The acid source can be one of phosphoric acid, sulfuric acid, or boric acid. The carbonization source can include pentaerythritol, sorbitol, mannitol, dextrin, starch, phenol formaldehyde resin, and a char-forming polymer. The foaming source is typically a nitrogen-containing compound, such as urea, urea-formaldehyde resin, melamine, dicyandiamide, and polyamide.

[0088] The intumescent flame retardant herein is preferably mixed in the polymer component that undergoes injection molding herein, or the intumescent flame retardant herein can be applied as a coating on the density-reduced component produced herein that contains a porous structure. When the intumescent flame retardant is mixed in the polymer component and foamed during the process of increasing the mold cavity spacing, the foamed core of the component provides thermal insulation and flame retardant properties. It can also be understood that in the case of a coating, the porous component herein provides thermal insulation capabilities as well as an intumescent flame retardant layer.

[0089] The flame retardant is preferably a flame retardant disclosed in U.S. Patent Publication No. 2019 / 0264002 (titled Flame Retardant Propylene Composition). That is, a first flame retardant including ammonium polyphosphate and one or more phosphates, the phosphate being selected from the following group, the group including melamine phosphate, melamine polyphosphate, melamine pyrophosphate, piperazine phosphate, piperazine polyphosphate, piperazine pyrophosphate and 2-methylpiperazine monophosphate.

[0090] It is preferred to use a second flame retardant mixed with the first flame retardant, and the second flame retardant preferably includes an aromatic phosphate. The aromatic phosphate is preferably selected from one or more of the following: resorcinol bis(diphenyl phosphate); tetraphenyl resorcinol bis(diphenyl phosphate); bisphenol A bis(diphenyl phosphate); bisphenol A diphosphate; resorcinol bis(di-2,6-xylyl phosphate), phosphoric acid, mixed esters with [1,1'-biphenyl]-4,4'-diol and phenol; polymer of phosphorus chloride and 1,3-benzenediol, phenyl ester; 1,3-phenylene-tetrakis(2,6-dimethylphenyl) diphosphate; isopropenylphenyl diphenyl phosphate; 4-phenylphenol formaldehyde phenylphosphonate; tris(2,6-xylyl) phosphate; resorcinol bis(di-2,6-xylyl phosphate); bisphenol S bis(diphenyl phosphate); resorcinol-bisphenol A phenyl phosphate.

[0091] Optionally, a metal oxide and the first and second flame retardants may also be included. Preferred metal oxides include zinc oxide. In addition, metal hydrates such as aluminum trihydrate (Al 2 O 3 ·3H2 O) and metal hydroxides such as aluminum hydroxide (Al(OH) 3 ).

[0092] Thus, in one embodiment, the first and second flame retardants (optionally together with the metal oxide, metal hydrate or metal hydroxide) are preferably introduced into a polymer component that is relied upon to form an injection molded part, wherein the mold cavity increases in size during the injection molding process. Thus, the first flame retardant may preferably be present in the polymer component at a level of 1.0% (wt) to 40.0% (wt), including all individual values ​​and increments therein. The second flame retardant may preferably be present in the polymer component in an amount of 1.0% (wt) to 15.0% (wt), including all individual values ​​and increments therein. The optional metal oxide, metal hydrate or metal hydroxide is preferably present in the polymer component at a level of 1.0% (wt) to 10.0% (wt), including all individual values ​​and increments therein.

[0093] In addition to the intumescent flame retardant, the flame retardant component herein may also preferably include an additional graphene additive, preferably a graphene powder available from Nanoxplore under the trade name Graphene Black, which graphene additive is believed to contain graphene platelets. The preferred level of graphene additive in the polymer component itself falls within the range of 0.5% (wt) to 5.0% (wt), including all individual values ​​and increments therein. More preferably, the graphene additive is present in the polymer component at a level of 3.0% (wt) to 5.0% (wt). In addition, the flame retardant component herein also preferably includes expandable graphite, which refers to graphite flakes that expand and form graphite carbon when exposed to elevated temperatures. The preferred expandable graphite additive herein is available under the trade name GrafGuard TM Expandable Graphite is available from NeoGraf. The preferred level of expandable graphite itself is present in the polymer component at a level of 5.0% (wt) to 25.0% (wt), including all individual values ​​and ranges therein. Particularly preferred flame retardant components herein include the intumescent flame retardant described herein, and 3.0% (wt) to 5.0% (wt) of graphene additives in combination with 10.0% (wt) to 20.0% (wt) of expandable graphite additives. It is also worth noting that by using graphene and / or expandable graphite additives, the injection molded parts herein are parts with EMI shielding.

[0094] In addition, as described above, the preferred IFR described herein can be applied as a coating on a porous component with reduced density. The IFR coating can preferably have a thickness in the range of 0.1 mm to 5.0 mm, including all individual values ​​and increments therein. For example, the IFR coating on the porous component with reduced density herein can have a thickness of 0.1 mm, 0.5 mm, 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, and 5.0 mm. Another expected thickness range is 0.1 mm to 2.5 mm, or even 0.1 mm to 1.0 mm.

[0095] Moreover, the aforementioned blowing agent and / or flame retardant can also be introduced into the polymer component when the polymer component is injected into the mold cavity. That is, the polymer component itself can be injected without blowing agent and / or flame retardant, wherein these additives are introduced in the injection molding cycle.

[0096] Therefore, it can now be understood that the present invention relates to a method for forming an injection molded part, the method comprising: providing an injection mold comprising a first half mold and a second half mold, the injection mold providing a mold cavity between the first half mold and the second half mold, wherein the mold cavity includes one or more positions having an initial spacing of at least 2.0 mm; injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a foaming agent; increasing the initial mold cavity spacing by at least 2.0 mm at the one or more positions; and forming an injection molded part in the mold cavity from the polymer component, wherein the injection molded part includes a porous structure.

[0097] The present invention also relates to a method of forming an injection molded part, the method comprising: providing an injection mold comprising a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity comprises one or more locations having an initial spacing of at least 2.0 mm; injecting a polymer component into the mold cavity, the polymer component comprising a foaming agent; increasing the initial mold cavity spacing by at least 2.0 mm at the one or more locations; and forming an injection molded part in the mold cavity from the polymer component, wherein the injection molded part comprises a porous structure. The injection molded part can then be coated with an intumescent flame retardant.

[0098] The present invention also relates to a method for forming an injection molded part, the method comprising: providing an injection mold comprising a first half mold and a second half mold, the injection mold providing a mold cavity between the first half mold and the second half mold, wherein the mold cavity comprises one or more positions having an initial spacing, the positions providing one or more movable mold inserts, wherein the inserts are selectively retractable to increase the initial mold cavity spacing; injecting a polymer component comprising a flame retardant into the mold cavity, the polymer component comprising a foaming agent; selectively retracting at least one of the mold inserts to increase the initial mold cavity spacing at a first position in the mold and maintain the initial mold spacing at a second position in the mold.

[0099] The present invention also relates to a method for forming an injection molded part, the method comprising: providing an injection mold comprising a first half mold and a second half mold, the injection mold providing a mold cavity between the first half mold and the second half mold, wherein the mold cavity comprises one or more positions having an initial spacing; injecting a polymer component comprising a flame retardant into the mold cavity, the polymer component comprising: (a) a first polymer having a melt strength greater than or equal to 20.0 cn and a melt extensibility greater than or equal to 100 mm / sec; (b) a second thermoplastic polymer having a melt flow index greater than or equal to 10.0 g / 10.0 min; (c) reinforcing fibers; and (d) a foaming agent; increasing the initial mold cavity spacing at the one or more positions; and forming an injection molded part in the mold cavity from the polymer component, wherein the injection molded part comprises a porous structure.

[0100] The use of the preferred intumescent flame retardants herein (either mixed in the polymer component that undergoes foaming and porous structure formation during the mold expansion process, or as a coating on the resulting foamed polymer component) will have particular utility in vehicle applications where both thermal insulation and flame retardant properties are desirable. For example, batteries for vehicles have become such vehicle components where a fire-resistant battery housing has become a desirable feature, especially in view of the widespread use of lithium-ion battery type configurations.

[0101] Therefore, the present invention relates to a flame retardant battery housing, in particular for vehicles. The housing generally comprises a base portion and four walls and a top or cover, which may have an opening in which a terminal for external electrical connection is fixed. Therefore, by injection molding these components into a mold cavity, increasing the initial spacing of the mold cavity and foaming a polymer component containing an expanded flame retardant, and providing a battery housing with flame retardant properties, the present invention is able to form a porous base portion, a porous wall portion and / or a porous cover. In addition, it is expected that this battery housing will exhibit a combustion rating of V-0 under the UL-94 standard.

[0102] It is also contemplated herein that the injection molded parts comprising the porous structure herein may also be configured to provide electromagnetic interference (EMI) shielding of housings, particularly automotive articles for electric vehicles, and more particularly battery housings for electric vehicles. Thus, in the formed porous structure, the metal sheet or metal mesh 119 (again see Figure 3A ) can then be selectively positioned more towards one side of the component (compared to the other side of the component). The metal mesh or metal sheet preferably has a thickness of 0.05 mm to 0.50 mm. The metal mesh or metal sheet can be made of steel, aluminum, copper, nickel, iron or a metal alloy. The metal mesh or metal sheet can be coated with another metal (e.g. a metal plating, such as a silver plating, a copper plating or a nickel plating) or a polymer material. The thickness of the formed component including the metal mesh or metal sheet is preferably in the range of 2.5 mm to 5.0 mm, including all individual values ​​and increments therein.

[0103] As from Figure 3A It will be appreciated that after the metal sheet or mesh 119 is inserted and then the polymer resin composition is injected, the metal sheet or mesh will be positioned toward the movable insert 140. The injected resin will tend to solidify at or near the surface of the movable insert 140, which can be facilitated by controlling the temperature of the insert 140. It is also contemplated that some vacuum assistance may be used to selectively pull and position the metal sheet to one side of the mold.

[0104] like Figure 3B As shown, when retracted and the porous structure is formed, the majority of the metal sheet or metal mesh 119 will be selectively positioned more toward one side of the resulting part, i.e., the side of the part that is away from the resin injection location, such as away from or opposite to the injection unit 200 or runner 130, where the polymer resin component is introduced into the mold cavity. More specifically, 60% or more of the metal sheet or metal mesh is selectively positioned toward one side of the resulting part, i.e., the side of the part that is generally away from or opposite to the injection unit 200 or runner 130, where the resin is introduced into the mold cavity, and the resin flows so that the metal mesh or metal sheet is positioned on the other side of the mold. See again Figure 3B , wherein the metal mesh 119 is now located on the side opposite to the injection unit 200 or the runner 130. Thus, 60% (most) to 100% (all) of the metal sheet or metal mesh is now selectively positioned more toward one side of the component away from the injection unit than the other side, including all individual values ​​and increments therein.

[0105] It will also be appreciated that the metal sheet or mesh may preferably be positioned and held in tension within the mold cavity. Thus, the position and tension control of the metal sheet or mesh is preferably accomplished when the mold is closed and when the polymer component is injected into the mold cavity. Such positioning and tensioning is preferably provided by a retaining or clamping mechanism that preferably retains / clamps the metal sheet or mesh around the periphery of the metal sheet or mesh. This may also be accomplished by using a robotic gripper. Such tensioning provides relatively unconstrained sheet or mesh movement within the mold cavity during injection, during which the flow and downward pressure of the polymer component stretch the metal sheet or mesh and cause the metal sheet or mesh to contour to the opposing surfaces of the mold. Thus, the mesh or sheet is preferably tensioned to retain the mesh, but the mesh is preferably allowed some release or slip from the selected tensioning to enable the mesh to be pulled into the mold cavity.

[0106] Therefore, the component including the porous structure herein represents a conductive surface (electrically isolated mesh), at which the conductive surface can be referred to as the B-side surface, while the A-side surface remains non-conductive. It should be understood that the A side of the component can be understood as the first side, and the B side of the component can be understood as the second side, which is in contact with another component (such as the upper or lower part of the battery housing). This selected position of the metal sheet or mesh improves the safety (such as electrical isolation) of the EV battery housing made of the porous structure herein. In addition, preferably, the polymer resin component may contain graphene, graphite, metal whiskers, carbon black, metal oxides or ferrites, and the ferrite is preferably a ferrite including iron oxide (Fe 2 O 3 ), magnesium ferrite (MgFe 2 O 4 ) x Fe 3-x O 4 ) or magnesium zinc ferrite (MgZnFe 2 O 4 ).

[0107] The metal sheet or metal mesh 119 itself preferably has a thickness of 0.05mm to 0.50mm, including all individual values ​​and increments therein. The metal sheet or metal mesh itself can include one or more layers of metal material. In addition, the metal mesh is preferably such that it is expressed as a mesh size within the range of 40 meshes / inch to 300 meshes / inch. The metal sheet or metal mesh is preferably selected from steel, aluminum, copper, nickel, iron or a metal alloy. The metal sheet or mesh may also preferably be coated, including a polymer coating or a metal coating, such as silver plating, copper plating and / or nickel plating. It is contemplated that a metal coating is used to reduce the possibility of corrosion and also to improve EMI shielding. Therefore, a product that meets EMI shielding requirements is provided herein, which is supported by a supporting plastic structure, focusing on meeting structural and impact requirements.

[0108] It is also contemplated that, in place of the metal sheet or metal mesh 119 described above, a polymer composite sheet that already contains metal (e.g., a metal sheet or metal mesh) or other additives may be used to similarly provide EMI shielding. The thickness of such a polymer composite sheet is preferably in the range of 0.50 mm to 5.0 mm, more preferably 0.50 mm to 1.5 mm, including all individual values ​​and increments therein. Additives (which may be relied upon in such a plastic composite sheet to similarly improve EMI shielding) include, but are not limited to, graphene, graphite, metal whiskers, carbon black, or metal oxides, such as iron oxide. A formed component including such a polymer composite sheet (which contains a metal mesh or metal sheet or other additives to provide EMI shielding) may have a thickness in the range of 2.0 mm to 7.0 mm.

[0109] Although the preferred embodiments of the present invention have been described, it should be understood that various changes, modifications and variations can be made therein without departing from the spirit of the present invention and the scope of the appended claims. Therefore, the scope of the present invention will not be determined by reference to the above description, but should be determined by reference to the full scope of the appended claims and their equivalents. Moreover, it should be understood that the appended claims do not necessarily include the broadest scope of the invention that the applicant is entitled to claim, or the only way to claim the invention, or that all recited features are required.

[0110] Reference numerals list

[0111] 10 Products

[0112] 12 Injection molded parts

[0113] 14 Gasket parts

[0114] 16 Decorative covering parts

[0115] 22 Outer (epidermis) layer

[0116] 24 Outer (epidermis) layer

[0117] 25 With little to no areas of reduced density

[0118] 26 Middle (core) layer

[0119] 27 Epidermis

[0120] 50 Handle

[0121] 52 Handle hole

[0122] 58 Hinge

[0123] 60 Hinge pin hole

[0124] 66 Insert

[0125] 70 ribs

[0126] 100 Molding device

[0127] 110 Mould

[0128] 112 First half mold

[0129] 114 Second half mold

[0130] 117 Initial cavity spacing

[0131] 118 Mould cavity after retraction of movable mould insert

[0132] 119 Metal sheet or metal mesh

[0133] 122 first half mold molding surface

[0134] 124 second half mold molding surface

[0135] 130 Hot runner

[0136] 140 Movable insert

[0137] 142 Movable insert

[0138] 144 Movable insert

[0139] 200 Injection molding machines

[0140] 202 Injection unit

Claims

1. A method of forming an injection molded part, the method include: providing an injection mold including a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity includes one or more locations having an initial cavity spacing of at least 2.0 mm; injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a blowing agent; increasing the initial mold cavity spacing at the one or more locations by at least 2.0 mm; and An injection molded part is formed from a polymer component in the mold cavity, wherein the injection molded part includes a porous structure.

2. The method according to claim 1, in: The initial cavity spacing in the mold cavity is in the range of 2.0 mm to 10.0 mm.

3. The method according to claim 1, in: The increase of at least 2.0 mm in the initial spacing of the mold cavities is in the range of 2.0 mm to 40.0 mm.

4. The method according to claim 1, in: The injection mold includes one or more movable mold inserts, one or more of which are retracted to increase the initial spacing of the mold cavities by at least 2.0 mm.

5. The method according to claim 4, in: The one or more movable mold inserts are retracted to increase the initial mold cavity spacing by at least 2.0 mm to 40.0 mm.

6. The method according to claim 4, in: The injection mold includes 1 to 10 movable mold inserts.

7. The method according to claim 1, in: The mold cavity has a cross-section, and the initial cavity spacing of at least 2.0 mm is substantially uniform across the cross-section of the mold cavity.

8. The method according to claim 1, in: The blowing agent includes a physical blowing agent or a chemical blowing agent.

9. The method according to claim 1, in: The injection molded part shows a reduction in density of greater than 0% up to 80% at the one or more locations of the mold cavity.

10. The method according to claim 1, in: The injection molded part has a different reduction in density at one location in the mold cavity than at another location in the mold cavity.

11. The method according to claim 1, in: The injection molded part has a density reduction of 0% to 10.0% at one or more locations in the mold cavity and a density reduction of greater than 10% to 80% at one or more other locations in the mold cavity.

12. The method according to claim 1, in: As the polymer components are injected into the mold cavity, the porous structure begins to form.

13. The method according to claim 1, in: After the polymer components are injected into the mold cavity, the porous structure begins to form.

14. The method according to claim 1, in: The polymer component includes the reinforcing additive in the range of up to 60% by weight of the polymer component.

15. The method according to claim 15, in: The reinforcing additives include reinforcing fibers.

16. The method according to claim 16, in: The length of the reinforcing fibers is in the range of 0.5 mm to 13.0 mm.

17. The method according to claim 1, in: The injection molded part comprises an outer skin layer and a core layer, wherein the outer skin layer has a thickness of 0.25 mm to 2.0 mm and has a first density d 1 , the core layer has a second density d 2 , where d 1 >d 2 .

18. A method of forming an injection molded part, the method include: providing an injection mold including a first mold half and a second mold half, the injection mold providing a mold cavity between the first mold half and the second mold half, wherein the mold cavity includes one or more locations having an initial spacing of the mold cavity; providing one or more movable mold inserts, wherein the movable mold inserts are selectively retractable to increase the initial spacing of the mold cavities; injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a blowing agent; At least one of the movable mold inserts is selectively retracted to increase the initial cavity spacing at a first position in the injection mold and maintain the initial cavity spacing at a second position in the injection mold.

19. The method according to claim 19, in: Selectively retracting at least one of the movable mold inserts to increase the mold cavity initial spacing at a first position provides a density reduction of greater than 10% to 80% of the polymer component.

20. The method according to claim 1, in: The flame retardant includes an intumescent flame retardant.

21. The method according to claim 19, in: The flame retardant includes an intumescent flame retardant.

22. The method according to claim 1, in: The flame retardant comprises: a first flame retardant, the first flame retardant comprising ammonium phosphate and one or more phosphates selected from the group consisting of melamine phosphate, melamine polyphosphate, melamine pyrophosphate, piperazine phosphate, piperazine polyphosphate, piperazine pyrophosphate, and 2-methylpiperazine monophosphate; A second flame retardant, wherein the second flame retardant includes an aromatic phosphate ester.

23. The method according to claim 19, in: The flame retardant comprises: a first flame retardant, the first flame retardant comprising ammonium phosphate and one or more phosphates selected from the group consisting of melamine phosphate, melamine polyphosphate, melamine pyrophosphate, piperazine phosphate, piperazine polyphosphate, piperazine pyrophosphate, and 2-methylpiperazine monophosphate; A second flame retardant, wherein the second flame retardant includes an aromatic phosphate ester.

24. A method of forming an injection molded part, the method include: providing an injection mold comprising a first mold half and a second mold half, the injection mold comprising a first side and a second side remote from the first side, the first side having a location for injecting a polymer component, The injection mold provides a mold cavity between a first mold half and a second mold half, wherein the mold cavity includes one or more locations having an initial cavity spacing of at least 2.0 mm; Positioning the metal sheet or metal mesh in the injection mold; injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a blowing agent; increasing the initial cavity spacing by at least 2.0 mm at one or more locations; and forming an injection molded part in the mold cavity from the polymer composition, wherein the injection molded part comprises a porous structure and respective first sides proximal to the location for injecting the resin and second sides distal to the location for injecting the plastic resin; and Therein, a majority of the metal sheet or metal mesh is positioned further towards a second side of the injection-molded part, away from a location for injecting the polymer component, than the first side of the injection-molded part.

25. The method according to claim 25, in: 60% or more of the metal mesh or metal sheet is positioned towards a second side of the injection-molded part, remote from the location for injecting the polymer component.

26. The method according to claim 1, in: The blowing agent and / or flame retardant is introduced into the polymer component when the polymer component is injected into the mold cavity.

27. A method of forming an injection molded part, the method include: providing an injection mold comprising a first mold half and a second mold half, the injection mold comprising a first side and a second side remote from the first side, the first side having a location for injecting a polymer component, The injection mold provides a mold cavity between a first mold half and a second mold half, wherein the mold cavity includes one or more locations having an initial cavity spacing of at least 2.0 mm; positioning a composite polymer sheet in the injection mold, the composite polymer sheet configured to provide EMI shielding; injecting a polymer component including a flame retardant into the mold cavity, the polymer component including a blowing agent; increasing the initial mold cavity spacing at the one or more locations by at least 2.0 mm; and forming an injection molded part in the mold cavity from the polymer composition, wherein the injection molded part comprises a porous structure and respective first sides proximal to the location for injecting the resin and second sides distal to the location for injecting the plastic resin; and Wherein a majority of the composite polymer sheet providing EMI shielding is positioned further towards a second side of the injection molded part, distal from a location for injecting the polymer component, than the first side of the injection molded part.

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