Method and device for mechanical separation of multi-layer tapered interlayers

Abstract

A process for separating a first layer of a tapered multilayer interlayer sheet from a remaining portion is disclosed, which involves heating the tapered multilayer interlayer sheet and then separating the first layer of the tapered multilayer interlayer sheet from the remaining portion by pulling the first layer and the remaining portion of the tapered multilayer interlayer sheet in different directions in a defined orientation without causing wrinkling or tearing of the tapered multilayer interlayer sheet.

Description

[Background technology]

[0001] Multi-layer interlayers continue to expand their share of the interlayer market, but their recyclability in the extrusion process is limited because different layers can have different physicochemical properties. When multi-layer interlayer materials (including skin and core layers) are reintroduced into the skin layer extrusion process, the core layer material, which is immiscible with the skin layer material, forms small but discrete domains of the core layer material, causing a certain level of haze. Due to this haze formation, the amount of core layer material that can be reintroduced into the skin layer must be limited. The inability to reprocess this multi-layer material indefinitely represents a significant economic loss and environmental burden.

[0002] It is possible to manually peel the skin layers from a multi-layer sheet to demonstrate the concept of mechanical separation, however, a stable, consistent, and cost-effective mechanical separation operation would benefit from improved processes and mechanical devices.

[0003] U.S. Patent No. 5,368,978 discloses a method for delaminating an imaging material, comprising providing an imaging material comprising a donor element and a receiver element, heating the imaging material, applying opposing forces to the donor element and the receiver element to separate the imaging material into the donor element and the receiver element, and stacking the separated donor element. In a preferred method, one or both of the opposing forces is a vacuum, and stacking occurs by winding after separation when the vacuum is released from the donor element. An apparatus for delaminating an imaging material includes means for applying heat and pressure to the imaging material, means for applying a separation force to at least one of the donor element and the receiver element to form the imaging material, and means for separating the donor element and the receiver element. In a preferred embodiment, the apparatus further includes means for winding the donor element and means for preheating the imaging material before applying the separation force.

[0004] U.S. Patent No. 5,934,577 discloses a process for separating components of a multilayer material comprising at least one layer of base plastic (A) and a layer of plastic (B) separated by a layer of adhesive plastic (C), which process involves: (1) heating the material to a temperature T1 between the crystallization temperature (Tc) of plastic B and Tc-20°C; (2) then shredding the material by subjecting it to shear at about the same temperature, thereby causing delamination and converting the material into two small-sized strips, (X) consisting essentially of base plastic (A) and (Y) consisting essentially of plastic B and adhesive plastic (C); and (3) subsequently separating strips X and Y by electrostatic separation.

[0005] U.S. Pat. No. 10,513,102 discloses a peeling device including a transport roller configured to transport a laminate in which a first substrate and a second substrate having an opening are releasably laminated; a peeling roller disposed opposite the transport roller across the laminate and configured to peel the second substrate from the first substrate; a winding roller disposed spaced apart from the peeling roller and configured to wind up the second substrate peeled from the first substrate; and a winding assistant roller disposed between the peeling roller and the winding roller and having a stepped portion configured to maintain the width of the opening.

[0006] US2020 / 0147933A1 discloses a method for recycling an interlayer film for laminated glass, the method comprising a step of separating a layer including layer A and a layer including layer B from an interlayer film for laminated glass (1) including at least layer A and layer B.

[0007] WO2022 / 250944 discloses a process for separating a first layer of a multilayer interlayer sheet from a remaining portion thereof, which comprises heating the multilayer sheet and then separating the first layer of the multilayer interlayer sheet from the remaining portion thereof by pulling the first layer and the remaining portion of the multilayer interlayer sheet in different directions in a defined orientation.

[0008] There remains a need for methods and devices for separating layers of multi-layer interlayers, particularly multi-layer tapered (or wedge-shaped) interlayers, to facilitate reworking of materials in the manufacturing process.

[0009] Tapered (or wedge-shaped) interlayers often refer to head-up display ("HUD") interlayers, or interlayers for HUD systems. These HUD interlayers are often used in laminated safety glass in vehicles equipped with HUD systems. HUD systems project an image of the instrument cluster or other important information onto a location on the windshield within the vehicle driver's line of sight. Such displays allow the driver to maintain focus on the ensuing driving route while visually accessing dashboard, navigation, and / or safety information.

[0010] One way to reduce ghost images in windshields is to orient the inner and outer glass panels at an angle relative to each other, thereby aligning the primary image reflected on the inner panel with the secondary image reflected on the outer panel, creating a single image. Typically, this is accomplished by using a wedge-shaped or "tapered" interlayer that includes at least one region of non-uniform thickness (i.e., a wedge shape rather than a constant or uniform thickness profile), thereby displacing the outer panel relative to the inner panel. With advances in tapered interlayers, a need exists for a method or process that facilitates separating layers of the tapered interlayer for rework or recycling in the manufacturing process. Summary of the Invention

[0011] In one aspect, the present invention relates to a continuous process for separating a first layer of a tapered multilayer interlayer sheet having a thick side and a thin side from a remaining portion, the process comprising heating the tapered multilayer sheet to an elevated temperature and then separating the first layer of the tapered multilayer interlayer sheet from the remaining portion by pulling the first layer and the remaining portion of the tapered multilayer interlayer sheet in opposite directions. According to this aspect, a positioning roll, which is also a heating unit and positioned prior to the separation point, is positioned to be tilted in the Z and / or Y directions to prevent the thick side of the tapered multilayer interlayer from shifting toward the center of the roll during the continuous process. The positioning roll can be tilted between panels holding the roll by up to about 1% of the roll length in the Z direction and up to about 0.5% of the roll length in the Y direction, as further described below.

[0012] In another aspect, the present invention relates to a continuous process for separating a first layer of a tapered multilayer interlayer sheet from a remaining portion, the process comprising heating the tapered multilayer sheet to a high temperature and then separating the first layer of the tapered multilayer interlayer sheet from the remaining portion by pulling the first layer and the remaining portion of the tapered multilayer interlayer sheet in different directions in a certain orientation, and further comprising tilting a positioning roll disposed between a separate heating unit and the separation point in the Z direction and / or the Y direction during the continuous process to prevent the thick side of the tapered multilayer interlayer from shifting toward the center of the roll. Thus, according to the present invention, the positioning roll may also function as a heating unit, or a heating unit may be provided separately from the positioning roll. According to the present invention, angle α is defined by the first layer and the tapered multilayer sheet at the separation point, angle β is defined by the tapered multilayer sheet at the separation point and the remainder of the tapered multilayer sheet, and angle γ is defined by the first layer and the remainder of the tapered multilayer sheet at the separation point, such that the following equations are satisfied: β / α≧1 30°≦γ≦180° α+β+γ=360°.

[0013] According to the present invention, the tilt of the positioning roll in the Z and / or Y direction and the described orientation are maintained during the continuous process. The tilt of the positioning roll requires further clarification of the aforementioned angle. The amount of tilt of the positioning roll can be changed depending on the wedge angle of the tapered multilayer interlayer. Because the amount of tilt of the positioning roll in the Z and / or Y direction is relatively small, the separation angles α and β only change slightly. When the positioning roll is changed, the roll moves in the Z and / or Y direction, so the angle α at one end of the roll is slightly different from the angle α at the other end of the roll. The same is true for angle β. As explained below, because the amount of tilt of the positioning roll in the Z and / or Y direction is relatively small, the angles only change slightly. Along the positioning roll, the angles α and / or β vary slightly from one end of the roll to the other, compared to when the positioning roll is not tilted (or is stationary at the origin). When used in the above formula, angles α and β should be selected so that angle β is at a minimum (the point on the positioning roll where angle β is at a minimum and defined by the first layer and the tapered multilayer sheet at the separation point), and angle α should be selected so that angle α is at its maximum level, which is defined by the tapered multilayer sheet at the separation point and the remainder of the tapered multilayer sheet. The relative formulas for α, β, and γ above are still satisfied.

[0014] In one embodiment, the continuous process for separating a first layer from a remainder of a tapered multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the positioning roll disposed between the heating unit and the separation point is positioned to tilt in the Z direction by up to about 1% of the positioning roll length, or in the Y direction by up to about 0.5% of the positioning roll length, or both, i.e., in the Z direction by up to about 1% of the positioning roll length and in the Y direction by up to about 0.5% of the positioning roll length, to prevent the thick side of the tapered multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing.

[0015] In another embodiment, a continuous process for separating a first layer from a remainder of a tapered poly(vinyl acetal) multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the positioning roll disposed between the heating unit and the separation point is positioned to tilt in the Z direction by up to about 1% of the positioning roll length, or in the Y direction by up to about 0.5% of the positioning roll length, or both, i.e., in the Z direction by up to about 1% of the positioning roll length and in the Y direction by up to about 0.5% of the positioning roll length, to prevent the thick side of the tapered poly(vinyl acetal) multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing.

[0016] In another embodiment, the continuous process for separating a first layer from a remainder of a tapered multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the heating unit, which also functions as a positioning roll, is positioned before the separation point so as to slope up to about 1% of the positioning roll length in the Z direction, or up to about 0.5% of the positioning roll length in the Y direction, or both, i.e., up to about 1% of the positioning roll length in the Z direction and up to about 0.5% of the positioning roll length in the Y direction, to prevent the thick side of the tapered multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing.

[0017] In another embodiment, a continuous process for separating a first layer from a remainder of a tapered poly(vinyl acetal) multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the heating unit (which also functions as a positioning roll) positioned before the separation point is positioned to tilt by about 1% of the positioning roll length in the Z direction, or by about 0.5% of the positioning roll length in the Y direction, or both, i.e., by about 1% of the positioning roll length in the Z direction and by about 0.5% of the positioning roll length in the Y direction, to prevent the thick side of the tapered poly(vinyl acetal) multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing.

[0018] In another aspect, the invention relates to an intermediate layer comprising a first layer obtained by the process described herein. In a further aspect, the invention relates to a composition comprising a first layer obtained by the process described herein.

[0019] In another aspect, the present invention relates to an apparatus for carrying out the method of the present invention.

[0020] Further aspects of the present invention are disclosed and claimed herein. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a method for mechanically recycling a multi-layer interlayer. [Figure 2] 1 is a schematic diagram of a device according to the invention for mechanically separating multiple interlayers; FIG. [Figure 3] FIG. 1 is a schematic diagram of the proper orientation of the membrane during separation. [Figure 4] 10 is a schematic diagram of the mechanical separation of a tapered multi-layer interlayer showing the tilt of the positioning roll in the Z and / or Y directions. [Figure 5] 1(a) and 1(b) are diagrams showing the position of the positioning roll relative to the Cartesian axes. [Figure 6-1] 1(a)-(h) are a series of diagrams showing the tilt of the positioning roll relative to Cartesian coordinates. [Figure 6-2]1(a)-(h) are a series of diagrams showing the tilt of the positioning roll relative to Cartesian coordinates. [Figure 7] 10(a) to 10(d) are diagrams showing the inclination of the positioning roll in the Z direction at an angle q as viewed from the XZ plane. [Figure 8] 10(a) to 10(d) are diagrams showing the inclination of the positioning roll in the Y direction at an angle -y as viewed from the XY plane. [Figure 9] FIG. 2 is another schematic view of a device according to the invention for mechanically separating multiple interlayers. [Figure 10] FIG. 2 is another schematic view of a device according to the invention for mechanically separating multiple interlayers. [Figure 11] FIG. 1 is a schematic diagram of the proper orientation of the membrane during separation. [Figure 12] FIG. 1 is a schematic diagram of the proper orientation of the membrane during separation. [Figure 13] 10 is a schematic diagram of the mechanical separation of a tapered multi-layer interlayer showing the tilt of the positioning roll in the Z and / or Y directions. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following embodiments and combinations are included within the scope of the present invention: A continuous process for separating a first layer from a remainder of a tapered multi-layer interlayer sheet, comprising: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the positioning roll, located between the heating unit and the separation point, is positioned to tilt in the Z direction by up to about 1% of the positioning roll length, or in the Y direction by up to about 0.5% of the positioning roll length, or both, i.e., in the Z direction by up to about 1% of the positioning roll length and in the Y direction by up to about 0.5% of the positioning roll length, to prevent the thick side of the tapered multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing. In some embodiments, the tapered multilayer interlayer sheet is a poly(vinyl acetal) sheet.

[0023] In this process, in some embodiments, a positioning roll is positioned between the heating unit and the separation point, and the positioning roll is positioned and tilted in the Z direction by about 1% of the positioning roll length and in the Y direction by about 0.5% of the positioning roll length. In other embodiments, the heating unit may itself function as the positioning roll, and a separate positioning roll is not required.

[0024] In some embodiments, the first layer comprises a poly(vinyl butyral) polymer having a Tg of about 25° C. to about 40° C. In some embodiments, the tapered multilayer interlayer sheet is heated in step a) to a temperature of 30° C. to 70° C. In some embodiments, at least a portion of the remaining portion of the tapered multilayer interlayer sheet comprises a poly(vinyl butyral) polymer having a Tg at least 15° C. lower than the Tg of the first layer.

[0025] In some embodiments of this process, during the separation step, the first layer is pulled by a first layer pull roll and the remaining portion of the tapered multi-layer interlayer sheet is pulled by a remaining portion pull roll, wherein the distance between the first layer pull roll and the remaining portion pull roll is maintained at less than about 50% of the width of the sheet during separation.

[0026] In some embodiments, the process further comprises cooling one or more of the first layer and the remaining portion of the tapered multilayer interlayer sheet to a temperature below the Tg of the poly(vinyl butyral) of the first layer of the tapered multilayer interlayer sheet or the Tg of the poly(vinyl butyral) of the remaining portion of the tapered multilayer interlayer sheet; in some embodiments, the process further comprises cooling the first layer to a temperature of about 15°C to about 30°C, or the process further comprises cooling the remaining portion of the tapered multilayer interlayer sheet to a temperature of about -15°C to about 0°C.

[0027] In some embodiments, the distance between the first layer pull roll and the remaining portion pull roll while separation is occurring is less than about 15% of the width of the sheet, or the distance between the first layer pull roll and the remaining portion pull roll while separation is occurring is less than about 5% of the width of the sheet.

[0028] In some embodiments, the tapered multilayer interlayer sheet includes a core layer and skin layers on both sides of the core layer. In some embodiments, the first layer includes a first skin layer, the first skin layer being thicker than the other skin layers. Further, in some embodiments, the first layer includes a first skin layer, the first skin layer being thinner than the other skin layers.

[0029] In some embodiments, the tilt is at least 0.001 mrad. In some embodiments, the variation in wedge angle of the separated interlayer is about ±0.15 mrad.

[0030] In another embodiment, the continuous process for separating a first layer from a remainder of a tapered multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the heating unit (which also functions as a positioning roll) positioned just before the separation point is positioned to tilt by about 1% of the positioning roll length in the Z direction, or by about 0.5% of the positioning roll length in the Y direction, or both, i.e., by about 1% of the positioning roll length in the Z direction and by about 0.5% of the positioning roll length in the Y direction, to prevent the thick side of the tapered multilayer interlayer sheet from shifting toward the center of the positioning roll during the continuous process.

[0031] In another embodiment, a continuous process for separating a first layer from a remainder of a tapered poly(vinyl acetal) multi-layer interlayer sheet comprises: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter separating the first layer of the tapered multi-layer interlayer sheet from the remainder by pulling the first layer and the remainder of the tapered multi-layer interlayer sheet in different directions; during the continuous process, the angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to the angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The tapered multilayer interlayer sheet has a thick side and a thin side, and the heating unit positioned before the separation point is positioned to tilt by about 1% of the positioning roll length in the Z direction, or by about 0.5% of the positioning roll length in the Y direction, or both, i.e., by about 1% of the positioning roll length in the Z direction and by about 0.5% of the positioning roll length in the Y direction, to prevent the thick side of the tapered poly(vinyl acetal) multilayer interlayer sheet from shifting toward the center of the positioning roll during continuous processing.

[0032] Although the process of the present invention is described herein as continuous, the term "continuous" is not intended to be particularly limiting. Those skilled in the art of industrial processes will understand that continuous processes are distinct from batch processes, and that the longer a process can be maintained continuously, the greater the advantage in terms of throughput. Thus, an advantage of the process of the present invention is that, under steady state conditions, multi-layer sheet rolls can be continuously separated for a significant period of time, and the present disclosure allows one skilled in the art to adjust the process to maintain the desired continuity as it runs. Therefore, the present invention and claims are intended to encompass any process that can be artificially interrupted or disturbed to prevent the process from running continuously. Other aspects are as disclosed and claimed herein.

[0033] Thus, in one aspect, the present invention relates to a method and device for separating two layers of a tapered multilayer interlayer by (i) unwinding the tapered interlayer from the roller, (ii) heating the tapered interlayer with one or more heated rollers and / or a separate IR (infrared) heater, (iii) peeling the first or skin layer under a separation force, and (iv) collecting the separated skin layer and the remaining portion of the tapered multilayer sheet for subsequent reuse as an interlayer component. In this aspect, a positioning roll located between the heating unit and the separation point, or which also functions as a heating unit, is positioned to be tilted in the Z and / or Y directions to prevent the thick side of the tapered multilayer interlayer from shifting toward the center of the roll during a continuous process. The positioning rolls can be tilted between the panels holding the rolls by up to about 1% of the roll length in the Z direction, or up to about 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or less, and up to about 0.5% of the roll length, or up to about 0.4, 0.3, 0.2, 0.1 or less, in the Y direction, as further described below.

[0034] In some embodiments, the heating unit and / or positioning roll is tilted in the Z direction by at least 0.01 milliradians and less than 0.05 milliradians.

[0035] In another aspect, the present invention relates to a method and device design in which the core and skin materials of tapered acoustic multilayer interlayer rework material (also referred to as wedge-shaped or head-up display (“HUD”) interlayers or sheets), e.g., rolls up to about 1.4 m wide and up to 500 kg in weight (longer, heavier rolls can be used), are separated by mechanically peeling one skin layer of the tapered multilayer interlayer sheet, e.g., at a speed of 2-20 m / min, thereby allowing the recovered skin layer to be used in unlimited extrusion molding. See FIG. 1 for a general overview of the process. As used herein, tapered multilayer interlayer refers to a tapered or wedge-shaped interlayer having a core layer and two skin layers (i.e., a triple-layer interlayer), although, with appropriate modifications, tapered multilayer interlayers having more layers can also be used.

[0036] Thus, the present invention relates to methods and devices that can mechanically separate a first or skin layer from a tapered (or wedge-shaped) multilayer interlayer sheet (e.g., Eastman's Saflex™ acoustic HUD PVB interlayer). Thus, in this embodiment, the goal is to mechanically separate one skin layer from the core-skin bilayer of a tapered acoustic (wedge-shaped) triple-layer interlayer, although the scope of processable materials of the disclosed device is not limited to triple layers but includes tapered multilayer interlayers that are tapered or wedge-shaped and have more than two, three, five, or more layers in the cross-machine direction of the sheet, either partially or entirely. Separation is typically between the skin layer adjacent to the acoustic core layer and the remainder of the sheet, including the core layer itself.

[0037] As shown in FIG. 2 , in one embodiment, the mechanical separation device for unwinding the tapered multi-layer interlayer includes: (1) an unwinding unit; (2) an optional edge trim unit; (3) one or more tension roll(s); (4) a pre-positioning roll optionally with a cooling section; (5) a heating or annealing unit; (6) an additional or second positioning roll optionally with a cooling section; (7) a first layer pull roll for the first or skin layer; and (8) a remainder pull roll for the remainder of the sheet, which is typically a core-skin bilayer. , (9) one or more tension roll(s) for the first or skin layer(s); (10) one or more tension roll(s) for the remainder of the sheet, which is usually the core-skin bilayer; (11) a skin layer collection unit, which may be a winder, a container with or without a nip system, or a grinder (or other collection device); and (12) a core-skin bilayer collection unit, which may be a winder, a container with or without a nip system, or a grinder (or other collection device).

[0038] To unwind the tapered interlayer, there is one pre-positioning roll (4) that is used to guide or position the tapered interlayer as it unwinds from the unwinding unit (1). As shown in Figure 4, a second positioning roll (identified as roll (6) in Figure 2) is positioned between the heating unit and the separation point, and this positioning roll can be precisely tilted in the Z direction, in the Y direction, or in both the Z and Y directions to prevent the thick side of the tapered multi-layer interlayer from moving or shifting toward the center of the roll, causing wrinkles in the thin side of the sheet and ultimately causing process stoppages and / or sheet tears.

[0039] As shown in FIG. 9 , in one embodiment, the mechanical separation device for unwinding the tapered multi-layer intermediate layer may consist of: (1) an unwinding unit; (2) an optional edge trim unit; (3) one or more tension roll(s); (4) an optional pre-positioning roll optionally equipped with a cooling section; (5) a heating or annealing unit; (6) a positioning roll; (7) a first layer pull roll for the first or skin layer; (8) a remainder pull roll for the remainder of the sheet, which is typically a core-skin bilayer; (9) one or more tension roll(s) for the first or skin layer; (10) one or more tension roll(s) for the remainder of the sheet, which is typically a core-skin bilayer; (11) a skin layer collecting unit, which may be a winder, a container with or without a nip system, or a grinder (or other collecting device); and (12) a core-skin bilayer collecting unit, which may be a winder, a container with or without a nip system, or a grinder (or other collecting device). The positioning roll (6) is positioned by tilting as previously described herein to prevent creep.

[0040] As shown in FIG. 10 , in one embodiment, the mechanical separation device for unwinding the tapered multi-layer intermediate layer may consist of: (1) an unwinding unit; (2) an optional edge trim unit; (3) one or more tension roll(s); (4) an optional pre-positioning roll optionally equipped with a cooling section; (5) a heating or annealing unit that also functions as a positioning roll; (7) a first layer pull roll for the first or skin layer; (8) a remainder pull roll for the remainder of the sheet, which is typically a core-skin bilayer; (9) one or more tension roll(s) for the first or skin layer; (10) one or more tension roll(s) for the remainder of the sheet, which is typically a core-skin bilayer; (11) a skin layer collecting unit, which may be a winder, a container with or without a nip system, or a grinder (or other collecting device); and (12) a core-skin bilayer collecting unit, which may be a winder, a container with or without a nip system, or a grinder (or other collecting device). As shown in Figure 10, the optional second positioning roll is not present; instead, the sheet is fed directly from the heating or annealing unit (5) to a separation point where it is split and fed to a first layer pull roll (7) for the first or skin layer and a remainder pull roll (8) for the remainder of the sheet. The heating unit, which is also a positioning roll, is tilted as described herein to prevent creep of the sheet, i.e., to prevent the sheet from moving or shifting toward the center of the roll and wrinkling the thinner side of the sheet.

[0041] For unwinding the tapered intermediate layer, in another embodiment, there is one optional pre-positioning roll (4) used to guide or position the tapered intermediate layer as it unwinds from the unwinding unit (1). As shown in Figure 11, a positioning roll (identified as roll (6) in Figures 2 and 9) is located between the heating unit (5) and the separation point, and this positioning roll can be precisely tilted toward the Z direction, toward the Y direction, or toward both the Z and Y directions to prevent the thick side of the tapered multi-layer intermediate layer from moving or shifting toward the center of the roll, causing wrinkles on the thin side of the sheet and ultimately causing process stoppages and / or sheet breakage. As shown in Figure 12, the optional second positioning roll (6) is not present. Alternatively, the heating unit (5) can also function as a positioning roll, which can be precisely tilted towards the Z direction, towards the Y direction, or towards both the Z and Y directions to prevent the thick side of the tapered multi-layer interlayer from moving or shifting position towards the center of the roll, causing the thin side of the sheet to wrinkle or bunch up, ultimately causing the process to stop and / or the sheet to tear.

[0042] When the positioning roll or heating unit (or rolls) are tilted, the position of the end of the roll corresponding to the thin side of the sheet must be at least slightly above the position of the end of the positioning roll corresponding to the thick side of the sheet in the Cartesian Z direction, as shown in Figure 5. In addition, the position of the end of the positioning roll or heating unit corresponding to the thin side of the sheet must be the same as or less than the position of the end of the roll corresponding to the thick side of the sheet in the Y direction. As shown in Figure 5 and described further below, tilting either one or both ends of the positioning roll or heating unit (in the Z and / or Y directions) can accomplish this change to prevent wrinkles from forming as the sheet unwinds.

[0043] Figures 5(a) and 5(b) show the position of the tilted positioning roll relative to the Cartesian axes. In Figure 5(a), the end of the roll corresponding to the thicker side of the sheet is at the origin, and in Figure 5(b), the midpoint of the roll width is at the origin. The dotted rectangle inside the roll represents the positioning roll or heating unit, and the rectangle is drawn slightly outside the roll to clarify the dotted line.

[0044] It is possible to have one or more additional positioning roll(s) or tension bar(s) (or similar devices known in the art) positioned between the positioning roll (described below) and the separation point. In this case, the positioning roll or tension bar (or other device used to assist in positioning the sheet and provide the necessary tension) is referred to as a "positioning roll" when defining the present invention and the amount of tilt, and the described positioning roll may also be referred to as a heating unit when determining the amount of tilt in the Z and / or Y directions required to facilitate unwinding of the tapered interlayer, if the heating unit also functions as a positioning roll. As described above and shown in the figures, fewer positioning rolls are possible in some embodiments. Furthermore, additional rolls, tension bars, etc. (not shown) may be included as desired.

[0045] Figures 6(a)-6(h) are a series of diagrams illustrating the tilt of the positioning roll relative to Cartesian coordinates. In Figures 6(a)-6(d), the end of the roll corresponding to the thicker side of the sheet is at the origin, while in Figures 6(e)-6(h), the midpoint of the roll width is at the origin. In Figures 6(a) and 6(e), the coordinates X, Y, Z and axes ab, cd, and ef are fixed to the roll. In Figures 6(b) and 6(f), the roll is tilted by angle f about axis ab, which does not affect wrinkle prevention. In Figures 6(c) and 6(g), the roll is tilted by angle q about axis cd. In Figures 6(d) and 6(h), the roll is tilted by angle -y about axis ef.

[0046] Figures 7(a) to 7(d) show the tilt of the positioning roll in the Z direction at an angle q as viewed from the XZ plane. Figures 7(a) and 7(c) show the state before the roll is tilted, and Figures 7(b) and 7(d) show the state after the roll is tilted. In Figures 7(a) and 7(b), the end of the roll corresponding to the thicker side of the sheet is at the origin, while in Figures 7(c) and 7(d), the midpoint of the roll width is at the origin.

[0047] Figures 8(a) to 8(d) show the tilt of the positioning roll in the Y direction at an angle -y as viewed from the XY plane, with Figures 8(a) and 8(c) showing the state before tilting and Figures 8(b) and 8(d) showing the state after tilting. In Figures 8(a) and 8(b), the end of the roll corresponding to the thicker side of the sheet is at the origin, while in Figures 8(c) and 8(d), the midpoint of the roll width is at the origin.

[0048] The unwinding unit (1) may be motorized or non-motorized and ideally can handle roll widths of up to, for example, 1.4 m and roll weights of up to 500 kg (or more), although other lengths and weights may be used.

[0049] The optional edge trim unit (2) can trim either one or both sides of the sheet along the machine direction as needed before transferring the sheet to the heating unit (5). Trimming can be done, for example, to maintain a consistent sheet width, separate and collect only a desired portion of the sheet, and / or prevent edge tearing. Examples include, but are not limited to, trimming a beveled portion of the sheet or trimming the edges of a sheet without a core layer. Generally, it can be useful to trim at least about 25 mm from each edge with a fixed blade. This can be done before placing the roll in the unwinding unit (1) or at any point between the unwinding unit (1) and the heating unit (5).

[0050] One or more tension roll(s) (3) are typically motorized to pull the sheet from the unwinding unit (1) and feed it into a heating or annealing unit (5). If the tension is not properly set to flatten the sheet as it passes through the tension roll(s), the sheet may wrinkle in the cross-machine direction, causing uneven heating and processing problems.

[0051] For example, referring to Figure 2, a first positioning roll (4), optionally equipped with a cooling section, follows the tension roll (3) and is preferably located adjacent to the heating unit (5), or the main heat energy source of the annealing unit (5), to establish the proper level of tension by positioning the sheet on the correct path before it reaches the heating unit (5). This roll may have optional cooling capability for fine control of the sheet temperature. This roll is typically not motorized, but may be motorized if desired.

[0052] The heating unit (5) contacts one or both skin layers so that the interfacial bond energy between at least one of the skin layers and the core layer is sufficiently low. This allows one of the skin layers to be mechanically separated from the rest of the sheet when a pulling force is applied. The thermal energy source can be a single or multiple heated roll(s), or infrared heater(s), or any combination of both (or other heat sources known in the art), and can be located on one or both sides of the sheet. In commercial operations, it is important that the interface or orientation angle of the mechanically separated sheet shown in FIG. 3 is maintained and remains constant throughout the duration of the operation, i.e., the first layer is the layer that is removed from the rest of the sheet throughout the operation. Otherwise, the layer collected in the first layer collection unit may also include the remaining portion of the sheet, such as part of the core layer. Therefore, it may be preferable that thermal energy to the sheet is supplied primarily through conduction by the heated rolls.

[0053] The temperature range of the sheet surface closest to the thermal energy source, typically the first or skin layer, achieved by the annealing unit can range from about ambient or room temperature to about 70°C, or from about 25°C to about 70°C, or from 30°C to 65°C, or from 35°C to 60°C, or at least about 25°C, at least about 30°C, at least about 35°C or higher, or less than about 70°C, less than about 65°C, or less than 60°C, or as described elsewhere herein. This can be measured by an IR thermometer at the exit of the heating unit. If the temperature of the sheet surface is too low, mechanical separation of the sheet may not occur, resulting in sheet tearing. If the temperature of the sheet surface is too high, the mechanical integrity of the sheet may be reduced, making it difficult to handle or process and potentially complicating stable operation of the mechanical separation process. The annealing or heating unit (3) is preferably a motor-driven roller.

[0054] In other embodiments, the temperature of the sheet surface closest to the thermal energy source, typically the first or skin layer, achieved by the annealing unit is at least about 25°C, or at least about 26°C, or at least 27°C, or at least 28°C, or at least 30°C, or at least 32°C, or at least 35°C, and up to about 70°C, or up to about 65°C, or up to about 60°C, or up to about 55°C, or up to about 50°C.

[0055] The inclined positioning roll (6), optionally equipped with a cooling section (if present), is located opposite the heating unit (5) or the annealing unit's main heat energy source to establish the proper level of tension in the sheet by positioning it on the correct path before it reaches the separation point. This roll may have optional cooling capability for fine-tuning the sheet temperature. The positioning roll (6), optionally equipped with a cooling section, may also be a spreader roll designed to remove wrinkles from the sheet by surface action in the cross-machine direction so that the sheet is wrinkle-free and ready for clean separation when it reaches the separation point. This roll is typically not motor-driven.

[0056] Tapered multi-layer interlayers present greater challenges when unwinding and separating the first or skin layer from the core-skin bilayer. The pulling force in the mechanical separation process is consumed not only by separating the interfaces but also by stretching the skin and bilayers. Because the sheet is tapered, an imbalance (or difference) in the sheet thickness occurs in the cross-machine direction. The thicker side of the sheet inevitably experiences more force than the thinner side as it separates. As the sheet is unwound and pulled, the thicker side of the sheet gradually advances toward the center of the second positioning roll, causing the thinner side to wrinkle and disrupt the process. Over time, the separation line or process changes from a linear to a highly curved line (because the separation point no longer remains a straight line but instead becomes a parabolic curve or a smile or frown-shaped curve), ultimately making it impossible to continue unwinding and separating the layers without tearing the sheet.

[0057] To overcome this problem and prevent the tapered multilayer intermediate layer from shifting or wrinkling, the inventors discovered that by precisely tilting one of the rolls, such as the positioning roll (i.e., the positioning roll (6)) or the heating unit (5) located between the heating unit and the separation point, in the Z direction, the Y direction, or both the Z and Y directions, the thick side of the tapered multilayer intermediate layer is displaced toward the center of the second positioning roll (6), preventing wrinkling of the thin side of the sheet. Depending on the configuration, the tilted roll should be the roll closest to (or immediately preceding) the separation point. When the positioning roll (6) or the heating unit (5) is tilted, it is important that the position of the roll end corresponding to the thin side of the sheet is higher in the Z direction of the Cartesian coordinate system defined in FIG. 5 than the position of the roll end corresponding to the thick side of the sheet. In addition, the position of the roll corresponding to the thin side of the sheet must be equal to or lower than the position of the roll end corresponding to the thick side of the sheet in the Y direction. As shown in Figure 5, the change can be achieved by tilting either one or both ends of the positioning roll (6) or the heating unit (5).

[0058] The effect of precise tilting of the positioning roll (6) may be sufficient if only one end of the roll can be allowed to tilt, as shown in Figure 5(a). However, if the machine is modified so that both ends of the positioning roll (6) can be tilted (as in Figure 5(b)), even finer adjustments can be made on the equipment and in the process, controlling sheet separation and preventing wrinkles.

[0059] The tilt of the positioning roll or heating unit (or other roll) relative to Cartesian coordinates is further illustrated by Figures 6(a)-6(h). In Figures 6(a)-6(d), the end of the roll corresponding to the thicker side of the sheet is at the origin, while in Figures 6(e)-6(h), the midpoint of the roll width is at the origin. In Figures 6(a) and 6(e), the coordinates X, Y, Z and axes ab-cd-ef are fixed to the roll. Tilting the roll by angle f around axis ab, as in Figures 6(b) and 6(f), has no effect; the roll simply rotates in its original position. In Figures 6(c) and 6(g), the roll is tilted by angle q around axis cd. In Figure 6(c), the end of the roll corresponding to the thin side of the sheet is tilted in the Z direction, while in Figure 6(g), the end of the roll corresponding to the thin side of the sheet is tilted in the Z direction and the end of the roll corresponding to the thick side of the sheet is tilted in the -Z direction. This tilting in Figures 6(c) and 6(g) results in the same difference, or delta, in Z position between the two roll ends. In Figures 6(d) and 6(h), the rolls are tilted about axis ef by an angle -y. In Figure 6(d), the roll end corresponding to the thin side of the sheet is tilted in the -Y direction, while in Figure 6(h), the roll end corresponding to the thin side of the sheet is tilted in the -Y direction and the roll end corresponding to the thick side of the sheet is tilted in the Y direction. This tilting in Figures 6(d) and 6(h) results in the same delta in Y position between the two roll ends.

[0060] Figures 7 and 8 provide views from the XZ plane for tilting in the Z direction and the XY plane for tilting in the Y direction, respectively. As shown in Figure 7, the sheet is under tension as it passes through the positioning roll (6), so tilting the roll toward the Z direction moves the thick side of the sheet along the Z axis, which prevents the sheet from shifting toward the center of the roll (in other words, keeps the sheet in place to prevent wrinkles). In Figure 8, tilting the positioning roll (6) or heating unit (5) toward the Y direction (specifically, the -Y direction) fixes the thick side of the sheet on the Y axis under pulling tension, preventing the sheet from shifting toward the center of the roll.

[0061] The positioning roll (6) may be motorized or non-motorized. It may be completely cylindrical across the width of the roll, or it may have journals at one or both ends of the roll. In either case, the surface of the positioning roll that faces or contacts the sheet may be smooth or may have some surface roughness and / or patterning, and may be made of materials such as stainless steel, carbon steel, Teflon, natural rubber, or synthetic rubber. Additionally, the positioning roll (6) may be flat or slightly tapered to allow the sheet to unfold as it exits the roll. Optionally, it may be heated or cooled.

[0062] The position of the end(s) of the positioning roll can be adjustable to allow tilting of the positioning roll. For example, the movable range of all bolts on the panel that holds the bearing portion of the roll can be cut to allow the position of the roll to be adjusted. For example, metal plates on both sides of the panel can hold the bolts, and the entire part, including the metal plates and the bolts that hold the roll, can be tilted as needed within the cut range. The maximum tilt of the positioning roll in the Z direction is approximately 1% of the roll length between the two panels (or sides) that hold the roll in place. A tilt of approximately 1% of the roll length corresponds to an angle q of 10 milliradians. For some rolls or processes, the desired tilt in the Z direction is 0.8% or less (8 milliradians or less at angle q). In certain embodiments, the positioning roll can be tilted 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1% or less. The maximum tilt of the positioning roll in the Y direction is 0.5% of the roll length between the two panels holding the roll, which corresponds to a 5 milliradian -Y angle. For some rolls, the desired tilt in the Y direction is 0.4%, 0.3%, 0.2%, 0.1% or less (4 milliradians -Y angle or less). In certain embodiments, the positioning roll may be tilted 0.3%, 0.2%, 0.1% or less. These lengths or angles include the displacement or angle from both ends of the positioning roll (6).

[0063] If the heating unit or roll can be tilted (e.g., if there is no positioning roll or other roll immediately before the separation point), the position of the end(s) of the heating unit can be adjustable. For example, the movable range of all bolts on the panels that hold the bearing portion of the roll can be cut to allow the roll position to be adjusted. For example, metal plates on both sides of the panel can hold the bolts, and the entire part, including the metal plates and the bolts that hold the roll, can be tilted as needed within the cut range. The maximum tilt of the heating unit in the Z direction is approximately 1% of the roll length between the two panels (or sides) that hold the roll in place. A tilt of approximately 1% of the roll length corresponds to an angle q of 10 milliradians. For some rolls or processes, the desired tilt in the Z direction is 0.8% or less (8 milliradians or less at angle q). In certain embodiments, the heating unit can be tilted 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1% or less. The maximum tilt of the heating unit in the Y direction is 0.5% of the roll length between the two panels holding the roll, which corresponds to a 5 milliradian -Y angle. For some rolls, the desired tilt in the Y direction is 0.4%, 0.3%, 0.2%, 0.1% or less (4 milliradians -Y angle or less). In certain embodiments, the heating unit may be tilted 0.3%, 0.2%, 0.1% or less. These lengths or angles include the displacement or angle from both ends of the heating unit.

[0064] The required tilt can be very slight, such as at least 0.01 mrad or more, depending on various factors such as the wedge angle of the sheet, the roll width, the number of positioning rolls (if present), etc. In embodiments, the tilt of rolls such as positioning rolls or heating units can be very slight, only about 0.01 mrad or more.

[0065] As the tapered multilayer sheet passes through the process, it is then mechanically separated between a first layer pull roll (7) for the first layer or skin layer and a remainder pull roll (8) for the remainder or core-skin bilayer. The first layer pull roll (7) for the skin layer is downstream of the separation positioning roll (6) and retrieves the mechanically separated skin layer from the rest of the sheet. The remainder pull roll (8) for the core-skin bilayer is also downstream of the separation positioning roll (6) and the heating or annealing unit (5) and retrieves the remainder, i.e., the core-skin bilayer. If there is no second positioning roll (6) or if there are additional rolls after the second positioning roll (6), the remainder pull roll (8) for the core-skin bilayer is downstream of the heating or annealing unit (5) and / or any additional rolls (not shown) and retrieves the remainder, i.e., the core-skin bilayer.

[0066] In commercial operations, it is important that the interface or orientation angle of the mechanically separated sheet shown in Figure 3 be maintained and kept relatively constant throughout the duration of the operation, i.e., that the first layer be the layer that is removed from the rest of the sheet throughout continuous operation. If this is not the case, the layer recovered in the first layer collection unit may also include the remainder of the sheet, e.g., part of the core layer.

[0067] As shown in Figures 3, 11, and 12, in accordance with the present invention, angle α is the angle defined by the first layer and the tapered multilayer sheet at the separation point after the sheet exits the second positioning roll. Angle β is the angle defined by the tapered multilayer sheet and the remainder of the multilayer sheet at the separation point after the sheet exits the second positioning roll. Also shown in Figures 3, 11, and 12 is angle γ defined by the first layer and the remainder of the tapered multilayer sheet after the separation point. As shown, the sum of the three angles, α + β + γ, is 360°.

[0068] According to the invention, it is important that angle α is equal to or smaller than angle β, and especially the latter, and that this condition is maintained throughout the duration of the continuous sheet separating operation. Typically, separators are designed so that angle γ is equal to or smaller than 180° and equal to or larger than 30° throughout the duration of the continuous sheet separating operation.

[0069] Therefore, according to the present invention, angle α can be, for example, about 30 to about 150°, or about 35 to about 160°, or about 40 to about 165°. Furthermore, angle β can be, for example, about 90 to about 180°, or about 95 to about 150°, or 100 to 120°. Similarly, angle γ can be about 30 to about 180°, or 45 to 150°, or 50 to 120°.

[0070] In other aspects, angles according to the present invention may be as follows, where delta is β minus α: γ=180°;α=60°;β=120° Δ60° γ=150°;α=90°;β=120° Δ30° γ=120°;α=90°;β=150° Δ60° γ=100°;α=80°;β=180° Δ100°.

[0071] In one embodiment, to minimize wrinkling of the sheet after mechanical separation, the distance between the first pulling roll (7) for the skin layer and the remaining pulling roll (8) for the core-skin bilayer (defined as the distance between the centers of the two rolls (7) and (8)) can be, for example, less than 50% of the width of the sheet to be processed. This number is defined as y. It may be more desirable if y is less than 30%, or less than 20%, or less than 15% of the width of the sheet to be processed.

[0072] Additionally, the first pulling roll (7) and the remaining pulling roll (8) for the skin layers may be spreader rolls to prevent wrinkles from forming in the mechanically separated layers. As used herein, the term "spreader roll" means a roll designed to remove wrinkles by surface action in the cross-machine direction.

[0073] Just as the tension roll(s) (10) for the core-skin bilayer are preferably motorized synchronously with the remainder pull roll (8) for the core-skin bilayer, the tension roll(s) (9) for the skin layer are preferably motorized synchronously with the first pull roll (7) for the skin layer, which helps drive the entire mechanical separation process and allows for stable transfer of the separated first layer or skin layer and remainder or core-skin bilayer to the skin layer collection unit (11) and core-skin bilayer collection unit (12), respectively.

[0074] The skin layer collection unit (11) can be either a motorized winder, or a crusher, or a bin, or any other collection device. This is where the recovered skin layers are collected for reuse in the extrusion process, etc. Alternatively, the skin layers can simply be collected in a bin, etc., with or without a nip system to steadily feed the sheet into the bin, for further processing.

[0075] The core-skin bilayer collection unit (12) may be either a motorized winder, or a pelletizer, or a container, or any other collection device. The collected core-skin bilayer may be reused in extrusion, or may be further mechanically processed, or may be transferred for use in chemical recycling. Similarly, the core-skin bilayer may simply be collected in a container or the like, with or without a nip system to steadily feed the sheet into the container, and further processed.

[0076] The range of total sheet thickness that can be processed with the devices disclosed in the present invention is typically from about 0.254 mm to about 5.080 mm, or from 0.508 to 2.540 mm, or from 0.762 to 1.270 mm, although other sheet thicknesses may be possible.

[0077] The operating speed at which such mechanical separation occurs on the device disclosed herein can be, for example, about 2 to about 20 m / min, or 5 to 10 m / min, based on the unwinding speed of the sheet. Both pull rolls operate 1.1 to 2.5 times faster than the unwinding speed. In other words, the operating speed at the point of separation is 2.2 to 50 m / min, or 5.5 to 25 m / min.

[0078] The mechanical separation device can be started as follows: [a] Starting from the center of the leading edge of the triple-layer interlayer sheet, cut the sheet diagonally once in both directions to form an arrow-shaped leading edge of the sheet; [b] manually peel one skin layer from the triple-layer interlayer sheet at the leading edge of the arrow shape, and then continue separating the sheets for about 25 cm; [c] manually firmly press the separated first skin layer and core-skin bilayer onto the skin layer pull roll (7) and the core-skin bilayer pull roll (8), respectively, and run the machine at a very slow speed, e.g., 1.0 m / s. / min, [d] thread up the skin layer through the skin layer pull roll (7) to the skin layer tension roll(s) (9), [e] thread up the core-skin bilayer through the core-skin bilayer pull roll (8) to the core-skin bilayer tension roll(s) (10), [f] jog all motorized rolls to ensure a stable process is established, and [g] increase speed to the target to reach steady state.

[0079] It will be appreciated that once in steady state, the tapered multi-layer interlayer sheet moves through the device as follows: the sheet is unwound from the unwinding unit (1) and optional edge trim unit (2), then passes through a tension roll (3) at ambient temperature before reaching the first positioning roll (4). The (optional) first positioning roll (4), optionally equipped with a cooling section, can be cooled to, for example, about ambient temperature, or tap water temperature, or a temperature of about 10°C to about 30°C, or 15°C to 30°C, or 20°C to 25°C, such that the temperature of the surface of the sheet is, for example, about 15°C to about 30°C, or 20°C to 25°C.

[0080] The sheet is then contacted with a heating unit (5), preferably a heated roll, which heats the surface of the sheet closest to the heat energy source to a temperature of from about 35°C to about 80°C, or from 43°C to 75°C, or from 45°C to 65°C, or as described elsewhere herein.

[0081] In various embodiments, after the sheet is heated by the heating unit (5), it is conveyed to a second positioning roll (6), optionally equipped with a cooling section, which is positioned away from the first positioning roll and on the opposite side of the heating unit (5) or the main heat energy source of the heating unit (5). The second positioning roll (6) may be cooled, for example, as described above, so that the temperature of the surface of the sheet is about 5°C to about 40°C, or 10°C to 30°C, or 12°C to 35°C. Alternatively, the surface of the sheet in contact with the second positioning roll (6) may be cooled to a temperature of at least 5°C, or at least 10°C, or at least 12°C, or at least 15°C, up to about 40°C, or up to 35°C, or up to 30°C. In other embodiments, the optional second positioning roll (6) is not present, and the sheet is conveyed directly from the heating unit (5) to the separation point. In this case, the heating unit also functions as a positioning roll and is tilted accordingly.

[0082] After the sheet passes through the second positioning roll (6), or the heating unit (5) if the second positioning roll (6) is not present, the tapered multilayer sheet is mechanically separated in the previously described orientation by pulling the first layer by the first skin layer pull roll (7) and the remainder of the sheet by the remainder pull roll (8). As noted above, this mechanical separation begins at start-up, and thereafter the method and device of the present invention ensures that the two layers remain cleanly separated during continuous operation.

[0083] As mentioned above, to minimize wrinkling of the sheet after mechanical separation, in one embodiment, the distance between the first layer pull roll (7) for the skin layer and the remaining portion pull roll (8) for the core-skin bilayer (defined as the distance between the centers of the two rolls (7) and (8)) is less than about 30% of the width of the sheet being processed. It may be more desirable if the distance between the centers of the two rolls (7) and (8) is less than 25%, or less than 20%, or less than 15%.

[0084] As noted above, in an important embodiment, the tapered multilayer interlayer sheet comprises a tapered multilayer PVB interlayer, e.g., a tapered or wedge-shaped triple layer having a skin / core / skin cross-section. Although a particular PVB interlayer is described, a variety of interlayer materials can be used.

[0085] When the interlayer comprises polyvinyl butyral (PVB), the PVB resin can be produced by a known acetalization process by reacting polyvinyl alcohol ("PVOH") with butyraldehyde in the presence of an acid catalyst, isolating, stabilizing, and drying the resin. Such acetalization processes are disclosed, for example, in U.S. Pat. Nos. 2,282,057 and 2,282,026, and Wade, B. 2016, "Vinyl Acetal Polymers," Encyclopedia of Polymer Science and Technology. 1-22 (online, copyright 2016 John Wiley & Sons, Inc.), the entire disclosures of which are incorporated herein by reference. This resin is commercially available in various forms, for example, as Butvar® resin from Solutia Inc., a wholly owned subsidiary of Eastman Chemical Company.

[0086] As used herein, residual hydroxyl content in PVB (calculated as wt. % vinyl alcohol or wt. % PVOH) refers to the amount of hydroxyl groups remaining on the polymer chain after processing is complete. For example, PVB can be produced by hydrolyzing poly(vinyl acetate) to poly(vinyl alcohol) (PVOH) and then reacting the PVOH with butyraldehyde. The process of hydrolyzing poly(vinyl acetate) typically does not convert all of the acetate side groups to hydroxyl groups. Furthermore, the reaction with butyraldehyde typically does not convert all of the hydroxyl groups to acetal groups. As a result, in any finished PVB resin, there will typically be residual acetate groups (as vinyl acetate groups) and residual hydroxyl groups (as vinyl hydroxyl groups) as side groups on the polymer chain. As used herein, residual hydroxyl content and residual acetate content are measured on a weight percent (wt%) basis according to ASTM D1396.

[0087] The PVB resins of the present disclosure typically have a molecular weight of greater than 50,000 daltons, or less than 500,000 daltons, or from about 50,000 to about 500,000 daltons, or from about 70,000 to about 500,000 daltons, or from about 100,000 to about 425,000 daltons, as measured by size exclusion chromatography using low angle laser light scattering. As used herein, the term "molecular weight" refers to weight average molecular weight.

[0088] Various adhesion control agents ("ACAs") can be used in the interlayer of the present disclosure to control the adhesion of the interlayer sheet to the glass. In various embodiments of the interlayer of the present disclosure, the interlayer can include from about 0.003 to about 0.15 parts ACA per 100 parts resin, from about 0.01 to about 0.10 parts ACA per 100 parts resin, or from about 0.01 to about 0.04 parts ACA per 100 parts resin. Such ACAs include, but are not limited to, ACAs disclosed in U.S. Pat. No. 5,728,472 (the disclosure of which is incorporated herein by reference in its entirety), residual sodium acetate, potassium acetate, magnesium bis(2-ethylbutyrate), and / or magnesium bis(2-ethylhexanoate).

[0089] Other additives may also be incorporated into the interlayer to enhance the performance of the final product or to impart specific additional properties to the interlayer, including, but not limited to, dyes, pigments, stabilizers (e.g., UV stabilizers), antioxidants, antiblocking agents, flame retardants, infrared absorbers or screeners (e.g., indium tin oxide, antimony tin oxide, lanthanum hexaboride (LaB6), and cesium tungsten oxide), processing aids, flow promoters, lubricants, impact modifiers, nucleating agents, heat stabilizers, UV absorbers, dispersants, surfactants, chelating agents, coupling agents, adhesives, primers, reinforcing additives, and fillers, as well as other additives known to those skilled in the art.

[0090] Although the described embodiments refer to the polymer resin as PVB, those skilled in the art will understand that the polymer can be any polymer suitable for use in multilayer panels. Exemplary polymers include, but are not limited to, polyvinyl acetal (PVA) (e.g., poly(vinyl butyral) (PVB) or isomeric poly(vinyl isobutyral) (PVisoB)), polyurethane (PU), poly(ethylene-co-vinyl acetate) (EVA), polyvinyl chloride (PVC), poly(vinyl chloride-co-methacrylate), polyethylene, polyolefins, ethylene acrylic acid ester copolymers, poly(ethylene-co-butyl acrylate), silicone elastomers, epoxy resins, and acid copolymers such as ethylene / carboxylic acid copolymers and ionomers thereof derived from any of the aforementioned possible thermoplastic resins, combinations of the foregoing, and the like. PVB and its isomeric polymer PVisoB, polyvinyl chloride, and polyurethane are generally particularly useful polymers for interlayers, with PVB (and its isomeric polymers) being particularly preferred.

[0091] In a further embodiment, the diffusive interlayer can be a multi-layer interlayer. For example, the multi-layer interlayer can be composed of PVB / PVisoB / PVB. Other examples include PVB / PVC / PVB or PVB / PU / PVB. Further examples include PVC / PVB / PVC or PU / PVB / PU. Alternatively, the skin layers and core layer can all be PVB using the same or different starting PVB resins.

[0092] In one embodiment, the first or skin layer of the multilayer interlayer sheet comprises a PVB polymer having a Tg of, for example, about 20° C. to about 45° C., or 25° C. to 40° C., or 28° C. to 35° C. Alternatively, the Tg of the poly(vinyl butyral) can be at least about 20° C., or at least 25° C., or at least 28° C., up to about 45° C., or up to 40° C., or up to 35° C.

[0093] In some embodiments, the Tg of the layer adjacent to the first layer may be at least 12° C. lower, or at least 15° C. lower, or at least 20° C. lower, or at least 30° C. lower than the Tg of the first or skin layer.

[0094] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and the like used in the specification and claims are to be understood as modified in all instances by the term "about." Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations and may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Furthermore, ranges set forth in the present disclosure and claims are intended to specifically include the entire range, not just the endpoint(s). For example, a range stated as 0 to 10 is intended to disclose all integers between 0 and 10 (e.g., 1, 2, 3, 4, etc.), all decimal points between 0 and 10 (e.g., 1.5, 2.3, 4.57, 6.1113, etc.), and the endpoints 0 and 10.

[0095] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are intended to be reported precisely given the measuring methods used, however, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0096] It should be understood that the reference to one or more process steps does not exclude the presence of additional process steps before or after the combined recited steps, or the presence of intervening process steps between explicitly identified steps. Furthermore, the naming of process steps, components, or other aspects of the information disclosed or claimed in this application by letters, numbers, or the like is a convenient means of identifying separate activities or components, and unless otherwise indicated, the recited letters can be arranged in any order.

[0097] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, C n Reference to alcohol equivalents refers to multiple types of C n It is intended to include alcohol equivalents. Thus, the use of phrases such as "at least one" or "at least a portion" in one place is not intended to exclude plural referents from the use of "a," "an," and "the" in other places unless the context clearly dictates otherwise. Similarly, the use of phrases such as "at least a portion" in one place is not intended to suggest that the absence of such phrases in other places means "all" unless the context clearly dictates otherwise.

[0098] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be used alone, or any combination of two or more of the listed items can be used. For example, if a composition is described as containing components A, B, and / or C, the composition can include A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0099] The present invention can be further described by the following examples of embodiments, although it will be understood that these examples are included for illustrative purposes only and are not intended to limit the scope of the invention unless otherwise specified. [Example]

[0100] Example 1 In mechanical separation devices such as those shown in the figures, when a tapered (wedge-shaped) multilayer PVB interlayer is processed, one end of the positioning roll, located between the heating unit and the separation point, was modified so that its end could tilt toward the Z direction, perpendicular to an imaginary line defined by connecting the point where the multilayer interlayer exits the heating unit and the separation point (shown in Figures 4-8). The inter-panel (or side-to-side) distance holding the positioning roll (i.e., the roll distance plus any journals or other sections used to secure the roll in place) was 1,778 mm when not tilted.

[0101] The end of the positioning roll was inclined 7.112 mm, or 4 mrad, toward the Z direction. The wedge angle of the multilayer PVB interlayer to be separated was 0.41 mrad. The sheet width was 1.0 m. The interlayer was fed into the mechanical separation device and then into the positioning roll so that the thin side of the sheet passed through the inclined side of the positioning roll. The interlayer was fed at 10 m / min and mechanically separated at 20 m / min without any process instability (i.e., the first skin layer was successfully separated from the core-skin bilayer).

[0102] Example 2 When the tapered multilayer PVB interlayer was processed in the mechanical separation device, the ends of the positioning rolls located between the heating unit and the separation point were modified so that the roll ends could be tilted toward the Z direction as previously described. The distance between the panels holding the positioning rolls was 1,778 mm when not tilted.

[0103] One end of the positioning roll was tilted 3.556 mm, or 4 milliradians, toward the Z direction. The other end of the positioning roll was also tilted 3.556 mm, or 4 milliradians, toward the Z direction. The wedge angle of the multilayer PVB interlayer to be separated was 0.41 milliradians. The sheet width was 1.0 m. The interlayer was fed into the mechanical separation device and then into the positioning roll so that the thin side of the sheet passed through the tilted side of the positioning roll. The interlayer was fed at 10 m / min and mechanically separated at 20 m / min without any process instability (i.e., the first skin layer was successfully separated from the core-skin bilayer).

[0104] Example 3 In the mechanical separation device, when a wedge-shaped multilayer PVB interlayer was processed, one end of a positioning roll located between the heating unit and the separation point was modified so that the roll end could be tilted toward the Z direction, as previously described. The same end of the positioning roll was also modified so that it could be tilted toward the Y direction, defined by an imaginary line connecting the point where the multilayer interlayer exits the heating unit and the separation point. The distance between the panels holding the positioning roll was 1,778 mm when not tilted.

[0105] The end of the positioning roll was tilted 7.112 mm, or 4 mrad, toward the Z direction. It was tilted -0.003 mm, or -5 mrad, toward the Y direction. The wedge angle of the multilayer PVB interlayer to be separated was 0.41 mrad. The sheet width was 1.0 m. The interlayer was fed into the mechanical separation device and then into the positioning roll, with the thin side of the sheet passing through the tilted side of the positioning roll. The interlayer was fed at 5 m / min and mechanically separated at 10 m / min without any process instability (i.e., the first skin layer was successfully separated from the core-skin bilayer).

[0106] Example 4 In the mechanical separation device, when the wedge-shaped multilayer PVB interlayer was processed, there was no second positioning roll after the heating unit. One end of the heating unit was slightly tilted toward the Z direction as previously described. The distance between the panels holding the heating unit was approximately 1,778 mm when not tilted.

[0107] The end of the positioning roll was tilted toward the Z direction by more than about 0.01 milliradians and less than about 0.05 milliradians. The wedge angle of the separated multilayer PVB interlayer was about 0.15 milliradians. The sheet width was 1.0 m. The interlayer was fed into the mechanical separation device and then into the heating unit so that the thin side of the sheet passed through the tilted side of the heating unit. The interlayer was fed at 5 m / min and mechanically separated at 10 m / min without any process instability (i.e., the first skin layer was successfully separated from the core-skin bilayer).

[0108] Comparative Example 1 The wedge-shaped multilayer PVB interlayer was processed in an unmodified mechanical separation device in which the positioning rolls were not tilted in either the Z and / or Y directions. The distance between the panels holding the positioning rolls was 1,778 mm.

[0109] The wedge angle of the multilayer PVB interlayer was 0.41 milliradians. The sheet width was 1.0 m. When the mechanical separation process was initiated, the separation line across the width of the interlayer changed to a high-order curve (i.e., a nonlinear separation point such as a parabola, frown, or other curve that was not relatively linear). It was impossible to continue operation even at the very slow feed rate of 2 m / min and pull rate of 5 m / min.

[0110] Table 1 below shows details of Examples 1 to 4 and Comparative Example 1, and indicates whether stable separation was achieved. [Table 1]

Claims

1. 1. A continuous process for separating a first layer from a remainder of a tapered multi-layer interlayer sheet, comprising: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter, separating the first layer of the tapered multi-layer interlayer sheet from the remaining portion by pulling the first layer and the remaining portion of the tapered multi-layer interlayer sheet in different directions; during the continuous process, an angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to an angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The continuous process, wherein the tapered multilayer interlayer sheet has a thick side and a thin side, and the positioning roll positioned just before the separation point is positioned to tilt in the Z direction by up to about 1% of the positioning roll length, or in the Y direction by up to about 0.5% of the positioning roll length, or both, i.e., in the Z direction by up to about 1% of the positioning roll length and in the Y direction by up to about 0.5% of the positioning roll length, to prevent the thick side of the tapered multilayer interlayer sheet from shifting toward the center of the positioning roll during the continuous process.

2. 10. The continuous process of claim 1, wherein the positioning roll heats the tapered multi-layer interlayer sheet in step a).

3. 10. The continuous process of claim 1, wherein the multi-layer interlayer sheet is heated in step a) by a heating unit.

4. 10. The process of claim 1, wherein the positioning roll is positioned to tilt in the Z direction by up to about 1% of the positioning roll length and in the Y direction by up to about 0.5% of the positioning roll length.

5. The process of any of claims 1 to 4, wherein the first layer comprises a poly(vinyl butyral) polymer having a Tg of about 25°C to about 40°C.

6. The process of any of claims 1 to 5, wherein the tapered multi-layer interlayer sheet is heated in step a) to a temperature of from 30°C to 70°C.

7. 7. The process of any of claims 1-6, wherein at least a portion of the remaining portion of the tapered multilayer interlayer sheet comprises a poly(vinyl butyral) polymer having a Tg at least 15°C lower than a Tg of the first layer.

8. In the separating step, the first layer is pulled by a first layer pull roll, and the remaining portion of the tapered multi-layer interlayer sheet is pulled by a remaining portion pull roll; 8. The process of claim 1, wherein the distance between the first layer pull roll and the remainder pull roll is maintained at less than about 50% of the width of the sheet during the separation.

9. 9. The process of any of claims 1-8, further comprising cooling one or more of the first layer and the remaining portion of the tapered multilayer interlayer sheet below a Tg of the poly(vinyl butyral) of the first layer of the tapered multilayer interlayer sheet or below a Tg of the poly(vinyl butyral) of the remaining portion of the tapered multilayer interlayer sheet.

10. The process of any of claims 1 to 9, further comprising cooling the first layer to a temperature of about 15°C to about 30°C.

11. The process of any of claims 1 to 10, further comprising cooling the remaining portion of the tapered multi-layer interlayer sheet to a temperature of from about -15°C to about 0°C.

12. 12. The process of claim 1, wherein the distance between the first layer pull roll and the remainder pull roll during the separation is less than about 15% of the width of the sheet.

13. 13. The process of any of claims 1 to 12, wherein the distance between the first layer pulling roll and the remainder portion pulling roll during the separation is less than about 5% of the width of the sheet.

14. The process of any of claims 1 to 13, wherein the tapered multi-layer interlayer sheet comprises a core layer having skin layers on either side of the core layer.

15. The process of any preceding claim, wherein the first layer comprises a first skin layer, the first skin layer being thicker than the other skin layers.

16. The process of any preceding claim, wherein the first layer comprises a first skin layer, the first skin layer being thinner than the other skin layers.

17. The process of any preceding claim, wherein the positioning roll is tilted in the Z direction by at least 0.01 milliradians and less than 0.05 milliradians.

18. 1. A continuous process for separating a first layer from a remainder of a tapered poly(vinyl acetal) multi-layer interlayer sheet, comprising: a. heating the tapered multi-layer interlayer sheet to a temperature of about 25°C to about 70°C; and b. thereafter, separating the first layer of the tapered multi-layer interlayer sheet from the remaining portion by pulling the first layer and the remaining portion of the tapered multi-layer interlayer sheet in different directions; during the continuous process, an angle α defined by the first layer and the tapered multilayer interlayer sheet at the separation point is less than or equal to an angle β defined by the tapered multilayer interlayer sheet at the separation point and the remainder of the tapered multilayer interlayer sheet; The continuous process, wherein the tapered multilayer interlayer sheet has a thick side and a thin side, and the heating unit positioned before the separation point is positioned to tilt by up to about 1% of the roll length of the heating unit in the Z direction, or by up to about 0.5% of the roll length of the heating unit in the Y direction, or both, i.e., by up to about 1% of the roll length of the heating unit in the Z direction and by up to about 0.5% of the roll length of the heating unit in the Y direction, to prevent the thick side of the tapered poly(vinyl acetal) multilayer interlayer sheet from shifting toward the center of the heating unit during the continuous process.

19. The process of claim 18, wherein the first layer comprises a poly(vinyl butyral) polymer having a Tg of about 25°C to about 40°C.

20. 20. The process of claim 18 or claim 19, wherein the tapered multi-layer interlayer sheet is heated in step a) to a temperature of from 30°C to 70°C.

21. 21. The process of any of claims 18-20, wherein at least a portion of the remaining portion of the tapered multilayer interlayer sheet comprises a poly(vinyl butyral) polymer having a Tg at least 15°C lower than a Tg of the first layer.

22. The process of any of claims 18 to 21, wherein the heating unit is tilted in the Z direction by at least 0.01 milliradians and less than 0.05 milliradians.

23. An intermediate layer comprising the first layer obtained by the process according to any one of claims 1 to 22.

24. A composition comprising the first layer obtained by the process of any of claims 1 to 22.

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