Intermediate layer frame for encapsulating functional films

Abstract

A method for producing a functional intermediate layer stack disclosed herein includes: a) cutting out two L-shaped pieces from the corner of a bulk sheet of intermediate layer material, leaving the cut sheet intact; b) trimming one or more of the two L-shaped pieces or the cut sheet as necessary; c) joining the L-shaped pieces to form a rectangular frame defining a rectangular opening; d) arranging the rectangular frame around the functional material to obtain a framed functional sheet; and e) covering the framed functional sheet with a cut sheet to form a functional intermediate layer stack, wherein the cut sheet in step e) is the same sheet as the cut sheet in step a) or a different sheet.

Description

Technical Field

[0001] The present invention relates generally to an intermediate layer for encapsulating a functional film.

Background Art

[0002] The present invention relates to a method for efficiently reducing chips and process waste in the encapsulation process of a functional film, such as a switchable film. Smart glass and switchable glazing are manufactured by adding a switchable film to a laminate. The most common switchable films are based on polymer dispersed liquid crystals (PDLCs), suspended particle devices (SPDs), or electrochromic (EC) devices, photochromic devices, or photochromic / electrochromic devices. The switchable film is enclosed between thermoplastic intermediate layers such as plasticized polyvinyl butyral (PVB), ethyl vinyl acetate (EVA), or thermoplastic polyurethane (TPU) and adhered to glass.

[0003] Typically, these switchable films are cut slightly smaller than the total area of the laminate, and the presence of a boundary region between the glass and the intermediate layer protects the edges of the switchable film (U.S. Patent No. 8,995,039). One problem is that optical distortion can occur because there is no switchable film at the edge of the laminate. Therefore, the switchable film is surrounded by an intermediate layer frame to compensate for this non-uniformity in thickness.

[0004] This "frame" design is described, for example, in U.S. Patent No. 10,596,787. These intermediate layer frames are cut from a 0.5 mm thick PVB sheet so that, for example, a switchable film can be placed within the frame. On the other hand, the cut edges that come out from the central part of each sheet are currently disposed of as waste (Figure 1). The switchable film and the intermediate layer frame are sandwiched between intermediate layers and laminated between glass plates.

[0005] Therefore, in this field, there is a need for improved methods for preparing the intermediate frame in a way that reduces chips and process waste. [Overview of the Initiative]

[0006] In one embodiment, the present invention relates to a method for manufacturing a functional intermediate layer stack, the method comprising: a) cutting out two L-shaped pieces from the corner of a bulk sheet of intermediate layer material, leaving the cut sheet; b) trimming one or more of the two L-shaped pieces or the cut sheet as needed; c) joining the L-shaped pieces to form a rectangular frame defining a rectangular opening; d) arranging the rectangular frame around the functional material to obtain a framed functional sheet; and e) covering the framed functional sheet with a cut sheet to form a functional intermediate layer stack, which is a multilayer stack. According to the present invention, the cut sheet in step e) may be the same sheet as the cut sheet in step a) or a different sheet.

[0007] Further aspects of the present invention are disclosed and claimed herein. [Brief explanation of the drawing]

[0008] [Figure 1] This document describes a prior art method for cutting out an intermediate layer frame from a bulk sheet of intermediate layer material, which results in considerable waste. [Figure 2] This embodiment of the present invention shows how a rectangular frame for a functional sheet can be formed by cutting and joining L-shaped pieces from a bulk sheet or an intermediate layer sheet of a larger size than usual. The remaining portion of the cut sheet can be used as the top layer to form a functional stack. [Modes for carrying out the invention]

[0009] In one embodiment, the present invention relates to a method for manufacturing a functional intermediate layer stack, the method comprising: a) cutting out two L-shaped pieces from the corner of a bulk sheet of intermediate layer material, leaving the cut sheet; b) trimming one or more of the two L-shaped pieces or the cut sheet as needed; c) joining the L-shaped pieces to form a rectangular frame defining a rectangular opening; d) arranging the rectangular frame around the functional material to obtain a framed functional sheet; and e) covering the framed functional sheet with a cut sheet to form a functional intermediate layer stack, which is a multilayer stack having the aforementioned functionality. According to the present invention, the cut sheet in step e) may be the same sheet as the cut sheet in step a) or a different sheet.

[0010] In one embodiment, various functional materials can be used. Therefore, functional materials may include photopolymer materials, conductive materials, solar reflective materials, polymer-dispersed liquid crystal materials, suspended particle materials, electrochromic materials, photochromic materials, and electrochromic / photochromic materials.

[0011] In embodiments according to any of the embodiments described above, the cutting sheet in step e) may be the same sheet as the cutting sheet in step a).

[0012] In embodiments according to any of the embodiments described above, the cutting sheet in step e) may be a different sheet from the cutting sheet in step a).

[0013] In embodiments according to any of the above-described embodiments, the intermediate layer material may be a viscoelastic polymer.

[0014] In embodiments according to any of the embodiments described above, the viscoelastic polymer may include one or more of the following: polyvinyl acetal such as butyral, thermoplastic polyurethane, or ethylene vinyl acetate.

[0015] In embodiments according to any of the embodiments described above, the cut sheet in step a) and the cut sheet in step e) include polyvinyl butyral having a thickness of, for example, about 0.1 mm to 1.0 mm.

[0016] In embodiments according to any of the embodiments described above, the cut sheet in step a) and the cut sheet in step e) include polyvinyl butyral having a thickness of, for example, about 0.2 mm to 0.8 mm.

[0017] In embodiments according to any of the embodiments described above, the present invention may further include covering the framed switchable sheet with an additional cut sheet on the side opposite to the cut sheet of step e). In this embodiment, the stack may be considered a three-layer structure having cut sheets on both sides of the framed switchable sheet, although the stack is of course a multilayer intermediate layer.

[0018] In embodiments according to any of the embodiments described above, the present invention may further include arranging rigid substrates on both sides of a functional intermediate layer stack to form a functional laminate.

[0019] The inventors have found a novel approach to creating an intermediate layer frame in the encapsulation process of functional films such as switchable films, photopolymer films, conductive films, and solar reflective films, thereby reducing chips and process waste. Therefore, the present invention relates to a method for efficiently reducing chips and process waste in the encapsulation process of functional films such as switchable films.

[0020] According to the present invention, a functional laminate, such as a switchable glazing, is manufactured by adding a functional film to the laminate. The most common switchable films are based on polymer-dispersed liquid crystals (PDLCs), suspended particle devices (SPDs), or electrochromic (EC) devices. The switchable film can be bonded to glass by being trapped between thermoplastic intermediate layers such as plasticized polyvinyl butyral (PVB), ethyl vinyl acetate (EVA), or thermoplastic polyurethane (TPU).

[0021] The present invention provides a novel approach to designing intermediate frames used for functions such as switchable glazing. According to the present invention, the intermediate frame is made from two L-shaped segments cut from a larger-than-usual-size PVB sheet (Figure 2). The two L-shaped portions are then welded or soldered together to form a single intermediate frame, while the central portion of the larger-than-usual-size PVB sheet can be used as the top or bottom layer to laminate a switchable film onto the glass. This approach of constructing the intermediate frame from L-shaped segments and minimizing waste is a unique approach that has not been previously considered or implemented and is not obvious to those skilled in the art.

[0022] While this approach is particularly effective for switchable films, it is understood that it can be used for any functional film, regardless of the function it imparts to the laminate (including, for example, photopolymer films, conductive films, or solar reflective films). According to the present invention, there are also numerous approaches to welding the joints between pre-formed L-shaped PVB portions. Hot air welding or ultrasonic welding are examples (see, for example, U.S. Patent Publication No. US20200278540A1).

[0023] In one aspect, the present invention relates to a method for fabricating a functional intermediate layer stack. Thus, the present invention can include a wide variety of functions. In various embodiments, functional materials can include one or more of a photopolymer material, a conductive material, a solar radiation reflective material, a polymer dispersed liquid crystal material, a suspension particle material, an electrochromic material, a photochromic material, or an electrochromic / photochromic material, or a holographic optical element. Other suitable functions include solar power generation, transparent displays such as head-up displays, signage, roofing materials, and the like.

[0024] According to the present invention, two L-shaped pieces can be cut out from the corner of a bulk sheet of the intermediate layer material, and the cut sheet may be left behind. The L-shaped pieces are cut as appropriate for forming a rectangular frame by trimming as necessary. Since the L-shaped pieces are roughly shaped with an angle of approximately 90 degrees, when joined, each can form two sides of a rectangular frame.

[0025] The bulk sheet of the intermediate layer material can be selected from various materials and is sized to be suitable for both the L-shaped pieces and the cut sheet cut out from the bulk sheet and sized, for example, suitable for use as the uppermost layer and / or the lowermost layer.

[0026] In one aspect, depending on the purpose of use, the size of the bulk sheet is about 140 cm to 180 cm and can be 120 to 160 or 130 to 150 cm when used for forming a laminate for a windshield / roofing. In another aspect, for example, in the case of a conventional sunroof, the size of the bulk sheet can be about 80 cm × 100 cm, or 150 to 180, or 100 to 150.

[0027] Either one or both of the two L-shaped pieces, and the cut sheet, may be further trimmed before use as necessary or as desired.

[0028] Therefore, according to the present invention, the bulk sheet of the intermediate layer material can be selected from a variety of materials, particularly viscoelastic materials. The viscoelastic material may be polyvinyl acetal such as polyvinyl butyral. As described above, the L-shaped pieces that form the rectangular frame may be the same as or different from the cut sheet which can be considered an outer layer that can come into contact with the rigid substrate and form a functional laminate. If the material of the L-shaped pieces is different from the material of the cut sheet, a different bulk sheet will naturally be required.

[0029] Therefore, embodiments of the present invention relate to multilayer panels and methods for manufacturing multilayer panels. Generally, multilayer laminates consist of two glass or other applicable substrates and one or more polymer interlayer sheets sandwiched between them. Multilayer panels are typically manufactured by assembling at least one polymer interlayer sheet between two substrates. As described above, the multilayer interlayer may be configured as a three-layer interlayer having three separate polymer interlayer sheets, including a core layer and two surface layers positioned on either side of the core layer.

[0030] In some embodiments, the intermediate layer (e.g., core layer and surface layer) has a substantially constant or uniform thickness along its length. However, in alternative embodiments, the intermediate layer may have at least one region of non-uniform thickness. For example, an intermediate layer composed of a core layer and a surface layer may have a wedge shape in which the thickness of the intermediate layer varies (e.g., linearly or non-linearly) along its length. In some such embodiments, the thickness of the intermediate layer may vary due to a change in the thickness of the core layer (i.e., the thickness of the surface layer is substantially constant). Alternatively, the thickness of the intermediate layer may vary due to a change in the thickness of the surface layer (i.e., the thickness of the core layer is substantially constant). In further alternatives, the thickness of the intermediate layer may vary due to changes in the thickness of both the core layer and the surface layer.

[0031] To facilitate a more comprehensive understanding of the intermediate layers and multilayer panels disclosed herein, the meanings of certain terms used in this application are defined.

[0032] As used herein, the terms “polymer intermediate sheet,” “intermediate layer,” “polymer layer,” and “polymer melt sheet” may refer to a single-layer sheet or a multilayer intermediate sheet. A “single-layer sheet,” as the name suggests, is a single polymer layer extruded as one layer. A multilayer intermediate sheet, on the other hand, may include multiple layers, including separately extruded layers, co-extruded layers, or any combination of separately extruded and co-extruded layers. Thus, a multilayer intermediate sheet may include, for example, a combination of two or more single-layer sheets ("multilayer sheet"), two or more co-extruded layers ("co-extruded sheet"), a combination of two or more co-extruded sheets, a combination of at least one single-layer sheet and at least one co-extruded sheet, and a combination of at least one multilayer sheet and at least one co-extruded sheet. In various embodiments of the present invention, the multilayer intermediate sheet includes at least two polymer layers (e.g., single-layer or multiple co-extruded layers) arranged in direct contact with each other, each containing a polymer resin. As used herein, the term “resin” refers to polymer components (e.g., PVB) extracted by processes such as those described in more detail below. Typically, plasticizers, such as those described in more detail below, are added to the resin to form a plasticized polymer. In addition to polymers and plasticizers, resins may also contain other components, such as acetates, salts, and alcohols, as will be discussed later.

[0033] It should be noted that while this application often describes polyvinyl butyral ("PVB") intermediate layers as polymer intermediate layers of polymer resins, other thermoplastic intermediate layers besides PVB may also be used. Possible polymers include, but are not limited to, polyurethane, polyvinyl chloride, poly(ethylene vinyl acetate), and combinations thereof. These polymers can be used alone or in combination with other polymers. Therefore, where ranges, values, and / or methods (e.g., proportion of plasticizer components, thickness, and property-enhancing additives) are indicated for PVB intermediate layers in this application, these ranges, values, and / or methods, where applicable, should be understood to apply to other polymers and polymer blends disclosed herein, or, as is known to those skilled in the art, may be modified to apply to different materials.

[0034] As used herein, the term “molecular weight” refers to the weight-average molecular weight (Mw). The molecular weight of PVB resins can range from approximately 50,000 to approximately 600,000, approximately 70,000 to approximately 450,000, or approximately 100,000 to approximately 425,000 Daltons.

[0035] PVB resins can be produced by known aqueous or solvent acetalization processes, which involve reacting polyvinyl alcohol ("PVOH") with butyraldehyde in the presence of an acid catalyst, followed by separation, stabilization, and drying of the resin. Such acetalization processes are disclosed, for example, in U.S. Patents 2,282,057 and 2,282,026, the relevant disclosures of which are incorporated herein by reference.

[0036] In this specification, the terms "poly(vinyl acetal)" or "poly(vinyl butyral)" are used in general, but the resins described herein may contain, as stated above, any suitable aldehyde residue, including but not limited to isobutyraldehyde. In some embodiments, one or more poly(vinyl acetal) resins include at least one C1-C 10The compound may contain an aldehyde or at least one C4-C8 aldehyde residue. Suitable examples of C4-C8 aldehydes may include, but are not limited to, n-butyraldehyde, isobutyraldehyde, 2-methylbarrelaldehyde, n-hexylaldehyde, 2-ethylhexylaldehyde, n-octylaldehyde, and combinations thereof.

[0037] In many embodiments, plasticizers are added to a polymer resin to form a polymer layer or intermediate layer. Generally, adding plasticizers to a polymer resin improves the flexibility and durability of the resulting polymer intermediate layer. The plasticizer is incorporated between polymer chains, increasing the spacing between chains ("free volume"), thereby lowering the glass transition temperature (T) of the polymer resin. g It significantly lowers the glass transition temperature (T) and softens the material. Furthermore, by adjusting the amount of plasticizer in the intermediate layer, the glass transition temperature (T) can be changed. g It can also affect the glass transition temperature (T g ) is the temperature at which the intermediate layer transitions from a glassy state to a rubbery state. Generally, the higher the amount of plasticizer added, the higher the temperature. g The temperature becomes lower. In some embodiments, such as when the intermediate layer has an acoustic three-layer structure, the glass transition temperature of the inner core layer (i.e., the soft layer) is less than about 20°C, while the glass transition temperature of the outer surface layer (e.g., the hard layer) is above about 25°C.

[0038] Possible plasticizers include, but are not limited to, polymeric plasticizers such as polybasic acid esters, polyhydric alcohols, triethylene glycol di-(2-ethyl butyrate), triethylene glycol di-(2-ethylhexanoate) (known as "3-GEH"), triethylene glycol diheptanoate, tetraethylene glycol diheptanoate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, mixtures of heptyl adipate and nonyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified alkyd sebacate, and mixtures of phosphates and adipates, as well as mixtures and combinations thereof. 3-GEH is particularly preferred. Other suitable plasticizers include, but are not limited to, tetraethylene glycol di(2-ethylhexanoate) ("4-GEH"), di(butoxyethyl) adipate, bis(2-(2-butoxyethoxy)ethyl) adipate, dioctyl sebacate, nonylphenyltetraethylene glycol, and mixtures thereof.

[0039] Other suitable plasticizers may include, but are not limited to, blends of two or more different plasticizers, including the plasticizers described above. Further suitable plasticizers, or blends of plasticizers, may be formed from aromatic groups, such as polyadipates, epoxides, phthalates, terephthalates, benzoates, toluates, melitates, and other specialty plasticizers. Further examples include, but are not limited to, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, polypropylene glycol dibenzoate, isodecyl benzoate, 2-ethylhexyl benzoate, diethylene glycol benzoate, propylene glycol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol benzoate isobutyrate, 1,3-butanediol dibenzoate, diethylene glycol di-o-toluate, triethylene glycol di-o-toluate, dipropylene glycol di-o-toluate, 1,2-octyl dibenzoate, tri-2-ethylhexyl trimellitate, di-2-ethylhexyl terephthalate, bisphenol A bis(2-ethylhexanoate), ethoxylated nonylphenol, and mixtures thereof. In some embodiments, the plasticizer can be selected from the group consisting of dipropylene glycol dibenzoate, tripylene glycol dibenzoate, and combinations thereof.

[0040] Generally, the plasticizer content of polymer intermediates in this application is measured by weight as parts per 100 parts of resin ("phr"). For example, if 30 grams of plasticizer are added to 100 grams of polymer resin, the plasticizer content of the resulting plasticized polymer is 30 phr. Where the plasticizer content of a polymer layer is indicated in this application, the plasticizer content of a particular layer is determined based on the phr of the plasticizer in the molten material used to produce that particular layer. In some embodiments, high-rigidity intermediates include layers with plasticizer content of less than about 35 phr and less than about 30 phr.

[0041] According to some embodiments of the present invention, one or more polymer layers described herein may contain one or more plasticizers with a total plasticizer content of at least about 20 phr, at least about 25 phr, at least about 30 phr, at least about 35 phr, at least about 38 phr, at least about 40 phr, at least about 45 phr, at least about 50 phr, at least about 55 phr, at least about 60 phr, at least about 65 phr, at least about 67 phr, at least about 70 phr, or at least about 75 phr. In some embodiments, the polymer layer may also contain one or more plasticizers with a total plasticizer content of about 100 phr or less, about 85 phr or less, 80 phr or less, about 75 phr or less, about 70 phr or less, about 65 phr or less, about 60 phr or less, about 55 phr or less, about 50 phr or less, about 45 phr or less, about 40 phr or less, about 38 phr or less, about 35 phr or less, or about 30 phr or less. In some embodiments, the total plasticizer content of at least one polymer layer can be in the range of about 20 to about 40 phr, about 20 to about 38 phr, or about 25 to about 35 phr. In some embodiments, the total plasticizer content of at least one polymer layer can be in the range of about 38 to about 90 phr, about 40 to about 85 phr, or about 50 to about 70 phr.

[0042] If the intermediate layer includes a multilayer intermediate layer, the plasticizer content of two or more polymer layers in the intermediate layer may be approximately the same, and / or the plasticizer content of at least one polymer layer may differ from that of one or more other polymer layers. If the intermediate layer includes two or more polymer layers with different plasticizer content, the two layers may be adjacent to each other. In some embodiments, the difference in plasticizer content between adjacent polymer layers can be at least about 1, at least about 2, at least about 5, at least about 7, at least about 10, at least about 20, at least about 30, at least about 35 phr, and / or about 80 or less, about 55 or less, about 50 or less, or about 45 phr or less, or in the range of about 1 to about 60 phr, about 10 to about 50 phr, or about 30 to 45 phr. If there are three or more layers in the intermediate layer, the plasticizer content of at least two of the polymer layers in the intermediate layer may be similar, being within 10 phr, 5 phr, 2 phr, or 1 phr, while the plasticizer content of at least two of the polymer layers may differ from each other within the above ranges.

[0043] In some embodiments, one or more polymer layers or intermediate layers described herein may contain a blend of two or more plasticizers, for example, two or more of the plasticizers described above. When a polymer layer contains two or more plasticizers, the total plasticizer content of the polymer layer and the difference in total plasticizer content between adjacent polymer layers may fall within one or more of the above-described ranges. When the intermediate layer is a multilayer intermediate layer, one or more polymer layers may contain two or more plasticizers. In some embodiments, when the intermediate layer is a multilayer intermediate layer, at least one of the polymer layers containing the blend of plasticizers may have a higher glass transition temperature than a conventional plasticized polymer layer. This may, in some examples, add further rigidity to a layer that can be used, for example, as an outer "surface" layer of a multilayer intermediate layer.

[0044] In addition to plasticizers, it is also conceivable that adhesion control agents ("ACAs") can be added to polymer resins to form polymer intermediates. Generally, ACAs have the function of modifying and / or improving the adhesion strength of the intermediate to the glass panel when forming laminated panels. Possible ACAs include, but are not limited to, magnesium carboxylates / salts. Possible ACAs may also include those disclosed in U.S. Patent No. 5,728,472, which is incorporated herein by reference in whole, such as residual sodium acetate, potassium acetate, and / or magnesium bis(2-ethylbutyrate).

[0045] Other additives may be incorporated into the intermediate layer to enhance its performance in the final product and to impart specific additional properties to the intermediate layer. Such additives include, but are not limited to, dyes, pigments, stabilizers (e.g., UV stabilizers), antioxidants, antiblocking agents, flame retardants, IR absorbers or blockers (e.g., indium tin oxide, antimony tin oxide, lanthanum hexaboride (LaB6), and cesium tungsten oxide), processing aids, flow-promoting additives, lubricants, impact modifiers, nucleating agents, heat stabilizers, UV absorbers, UV stabilizers, dispersants, surfactants, chelating agents, coupling agents, adhesives, primers, reinforcing additives, and fillers, among other additives known to those skilled in the art.

[0046] One of the parameters used to describe the polymer resin components of the polymer intermediate layer of this application is the residual hydroxyl content (as vinyl hydroxyl content or poly(vinyl alcohol) ("PVOH") content). Residual hydroxyl content refers to the amount of hydroxyl groups remaining as side groups on the polymer chain after the processing is complete. For example, PVB can be produced by hydrolyzing poly(vinyl acetate) to poly(vinyl alcohol), and then reacting this poly(vinyl alcohol) with butyraldehyde to form PVB. In the process of hydrolyzing poly(vinyl acetate), not all acetate side groups are usually converted to hydroxyl groups. Furthermore, in the reaction with butyraldehyde, not all hydroxyl groups are usually converted to acetal groups. As a result, in any completed PVB, residual acetate groups (such as vinyl acetate groups) and residual hydroxyl groups (such as vinyl hydroxyl groups) are usually present as side groups on the polymer chain. In general, among the variables in the polymer manufacturing process, the residual hydroxyl content of the polymer can be adjusted by controlling the reaction time and reactant concentration. When used as a parameter in this specification, the residual hydroxyl content is measured in weight percent according to ASTM D-1396.

[0047] In various embodiments, the poly(vinyl butyral) resin contains approximately 8 to approximately 35 wt% residual hydroxyl groups calculated as PVOH, approximately 13 to approximately 30 wt% residual hydroxyl groups calculated as PVOH, approximately 8 to approximately 22 wt% residual hydroxyl groups calculated as PVOH, or approximately 15 to approximately 22 wt% residual hydroxyl groups calculated as PVOH. With respect to the high-rigidity intermediate layers disclosed herein, in one or more layers, the poly(vinyl butyral) resin contains more than approximately 19 wt% residual hydroxyl groups calculated as PVOH, more than approximately 20 wt% residual hydroxyl groups calculated as PVOH, more than approximately 20.4 wt% residual hydroxyl groups calculated as PVOH, and more than approximately 21 wt% residual hydroxyl groups calculated as PVOH.

[0048] In some embodiments, the poly(vinyl butyral) resin used in at least one polymer layer of the intermediate layer may include poly(vinyl butyral) resins having a residual hydroxyl content measured as described above of at least about 18, at least about 18.5, at least about 18.7, at least about 19, at least about 19.5, at least about 20, at least about 20.5, at least about 21, at least about 21.5, at least about 22, at least about 22.5 wt%, and / or about 30 or less, about 29 or less, about 28 or less, about 27 or less, about 26 or less, about 25 or less, about 24 or less, about 23 or less, or about 22 wt%.

[0049] Furthermore, one or more other polymer layers in the intermediate layer described herein may include another poly(vinyl butyral) resin with a lower residual hydroxyl content. For example, in some embodiments, at least one polymer layer of the intermediate layer may include a poly(vinyl butyral) resin having a residual hydroxyl content, as measured above, of at least about 8, at least about 8.5, at least about 9, at least about 9.5, at least about 10, at least about 10.5, at least about 11, at least about 11.5, at least about 12, at least about 13 wt%, and / or about 16 or less, about 15 or less, about 14 or less, about 13.5 or less, about 13 or less, about 12 or less, or about 11.5 wt% or less.

[0050] If the intermediate layer comprises two or more polymer layers, these layers may contain poly(vinyl butyral) resins having approximately the same residual hydroxyl content, or the residual hydroxyl content of the poly(vinyl butyral) resins in each layer may differ from one another. If two or more layers contain polyvinyl butyral resins having approximately the same residual hydroxyl content, the difference in residual hydroxyl content between the poly(vinyl butyral) resins in each layer may be less than about 2, less than about 1, or less than about 0.5 wt%. As used herein, the terms “difference in weight percentage” and “the difference between… is at least… weight percentage” refer to the difference between two given weight percentages, calculated by subtracting one value from the other. For example, a poly(vinyl acetal) resin with a residual hydroxyl content of 12 wt% and a poly(vinyl acetal) resin with a residual hydroxyl content of 14 wt% have a difference in residual hydroxyl content of 2 wt% (14 wt% - 12 wt% = 2 wt%). As used herein, the term “different” can refer to a value that is higher or lower than another value. Unless otherwise specified, all “difference” as used herein refers to the numerical value of the difference and does not refer to any particular sign of the value resulting from the order in which the numbers were subtracted. Therefore, unless otherwise specified, all “difference” as used herein refers to the absolute value of the difference between two numbers.

[0051] If two or more layers contain poly(vinyl butyral) resins with different residual hydroxyl content, the difference in residual hydroxyl content between these poly(vinyl butyral) resins can be at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 12, and at least about 15 wt%, as measured as described above.

[0052] Furthermore, the resin may be a polyvinyl ester with residual ester groups calculated as acetates in amounts of less than 35 wt%, less than 30 wt%, less than 25 wt%, less than 15 wt%, less than 13 wt%, less than 11 wt%, less than 9 wt%, less than 7 wt%, less than 5 wt%, or less than 1 wt%, with the remainder being acetal, preferably butyraldehyde acetal, but possibly containing trace amounts of other acetal groups, such as 2-ethylhexanal groups (see, for example, U.S. Patent No. 5,137,954, the entire disclosure of which is incorporated herein by reference). The residual acetate content of the resin can also be measured in accordance with ASTM D-1396.

[0053] In some embodiments, as described above, one or more of the polymer layers in the intermediate layer may be formed from a poly(vinyl acetal) resin. Such a poly(vinyl acetal) resin may have a residual acetate content, as measured above, of at least about 1, at least about 3, at least about 5, at least about 7 wt%, and / or about 15 or less, about 12 or less, about 10 or less, or about 8 wt% or less. If the intermediate layer includes a multilayer intermediate layer, two or more polymer layers may contain resins having substantially the same residual acetate content, or one or more resins in individual layers may have significantly different acetate content. If the residual acetate content of two or more resins is substantially the same, the difference in residual acetate content may be, for example, less than about 3, less than about 2, less than about 1, or less than about 0.5 wt%. In some embodiments, the difference in residual acetate content between two or more poly(vinyl butyral) resins in the multilayer intermediate layer may be at least about 3, at least about 5, at least about 8, at least about 15, at least 20, or at least about 30 wt%. When such resins are used in a multilayer intermediate layer, resins with different residual acetic acid content may be present in adjacent polymer layers. If the multilayer intermediate layer consists of three intermediate layers, including a pair of outer "surface" layers surrounding or sandwiching an inner "core" layer, for example, the residual acetic acid content of the resin in the core layer may be higher or lower. Furthermore, the residual hydroxyl content of the resin in the inner core layer may be higher or lower than that of the outer surface layer, and may fall within one or more of the above-mentioned ranges.

[0054] Furthermore, poly(vinyl acetal) resins with higher or lower residual hydroxyl and / or residual acetate content may also have different amounts of plasticizer when combined with at least one plasticizer. As a result, the properties of layers or regions formed from first and second poly(vinyl acetal) resins with different compositions may also differ within a single polymer layer or intermediate layer. In particular, for certain types of plasticizers, the compatibility of the plasticizer in the polymer is mainly determined by the hydroxyl content of the polymer. There is generally a correlation that higher residual hydroxyl content in the polymer leads to lower compatibility or capacity of the plasticizer. Conversely, lower residual hydroxyl content in the polymer generally leads to increased compatibility or capacity of the plasticizer. Consequently, poly(vinyl acetal) resins with high residual hydroxyl content tend to be less plasticized and have higher rigidity than similar resins with lower residual hydroxyl content. Conversely, poly(vinyl acetal) resins with low residual hydroxyl content tend to incorporate more plasticizer when plasticized with a given plasticizer, resulting in a softer polymer layer with a lower glass transition temperature than similar resins with high residual hydroxyl content. It is also possible that these trends may be reversed for specific resins and plasticizers.

[0055] When two poly(vinyl acetal) resins with different levels of residual hydroxyl content are blended with a plasticizer, the plasticizer can be distributed between polymer layers or regions. More plasticizer can be present in the layer or region with the lower residual hydroxyl content, while less plasticizer may be present in the layer or region with the higher residual hydroxyl content. Ultimately, an equilibrium state is reached between the two resins. Generally, by skillfully managing and utilizing this correlation between the residual hydroxyl content of the polymer and the compatibility / capacity of the plasticizer, it becomes possible to add the appropriate amount of plasticizer to the polymer resin and stably maintain the difference in plasticizer content within multilayer intermediates. This correlation also helps to stably maintain the difference in plasticizer content between two or more resins, where otherwise the plasticizer would migrate between resins.

[0056] As a result of plasticizer migration within the intermediate layer, the glass transition temperatures of one or more polymer layers may differ when measured individually compared to when measured as part of a multilayer intermediate. In some embodiments, the intermediate layer may include at least one polymer layer whose glass transition temperature outside the intermediate layer is at least about 33, at least about 34, at least about 35, at least about 36, at least about 37, at least about 38, at least about 39, at least about 40, at least about 41, at least about 42, at least about 43, at least about 44, at least about 45, or at least about 46°C. In some embodiments, this same layer may have a glass transition temperature within the polymer layer of at least about 34, at least about 35, at least about 36, at least about 37, at least about 38, at least about 39, at least about 40, at least about 41, at least about 42, at least about 43, at least about 44, at least about 45, at least about 46, or at least about 47°C.

[0057] In the same or other embodiments, at least one other polymer layer of the multilayer intermediate layer may have a glass transition temperature of less than 30°C, for example, the glass transition temperature measured when the intermediate layer is not part of a certain intermediate layer may be about 25°C or less, about 20°C or less, about 15°C or less, about 10°C or less, about 9°C or less, about 8°C or less, about 7°C or less, about 6°C or less, about 5°C or less, about 4°C or less, about 3°C ​​or less, about 2°C or less, about 1°C or less, about 0°C or less, about -1°C or less, or about -5°C or less. The same polymer layer may have a glass transition temperature measured outside the intermediate layer of about 25°C or less, about 20°C or less, about 15°C or less, about 10°C or less, about 9°C or less, about 8°C or less, about 7°C or less, about 6°C or less, about 5°C or less, about 4°C or less, about 3°C ​​or less, about 2°C or less, about 1°C or less, or about 0°C or less.

[0058] According to some embodiments, the difference in glass transition temperatures between two polymer layers, typically adjacent polymer layers within an intermediate layer, can be at least about 5, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, or at least about 45°C, while in other embodiments, two or more polymer layers can have glass transition temperatures of about 5, about 3, about 2, or about 1°C from each other. Generally, layers with lower glass transition temperatures are less rigid than layers with higher glass transition temperatures within the intermediate layer and can be placed between polymer layers with higher glass transition temperatures in the final intermediate layer structure.

[0059] For example, in some embodiments of the present application, the enhanced acoustic damping properties of a soft layer are combined with the mechanical strength of a hard / rigid layer to create a multilayer interlayer. In these embodiments, a central soft layer is sandwiched between two outer hard / rigid layers. This (hard) / / (soft) / / (hard) configuration creates a multilayer interlayer that is easy to handle, allows the use of conventional lamination methods, and can be composed of relatively thin and light layers. The soft layer is generally characterized by a low residual hydroxyl content (e.g., 16 wt% or less, 15 wt% or less, or 12 wt% or less, or any of the above disclosed ranges), a high plasticizer content (e.g., about 48 phr or more, or about 70 phr or more, or any of the above disclosed ranges), and / or a low glass transition temperature (e.g., less than 30°C, or less than 10°C, or any of the above disclosed ranges).

[0060] The polymer interlayer sheets described herein are assumed to be manufactured by any suitable process for manufacturing polymer interlayer sheets that are known to those skilled in the art and can be used in multilayer panels (such as glass laminates). For example, the polymer interlayer sheets are assumed to be formed by solution casting, compression molding, injection molding, melt extrusion, melt blowing, or any other procedure known to those skilled in the art in the production and manufacture of polymer interlayer sheets. Furthermore, in embodiments where multiple polymer interlayers are utilized, these multiple polymer interlayers are assumed to be formed by co-extrusion, inflation film, dip coating, solution coating, blade, paddle, air knife, printing, powder coating, spray coating, or any other process known to those skilled in the art. All of the polymer interlayer sheet manufacturing methods known to those skilled in the art are assumed to be possible methods in the manufacture of the polymer interlayer sheets described herein, but this application will focus on polymer interlayer sheets manufactured by extrusion and / or co-extrusion processes. The final multilayer glass panel laminate of this disclosure is formed using processes known in the art.

[0061] In the extrusion process, a thermoplastic resin and plasticizer, typically containing one of the resins and plasticizers described above, are pre-mixed and supplied to the extruder. Additives such as colorants and UV inhibitors (in liquid, powder, or pellet form) may also be used and can be mixed with the thermoplastic resin or plasticizer before reaching the extruder. These additives are incorporated into the thermoplastic polymer resin and the resulting polymer interlayer sheet, thereby improving the specific properties of the polymer interlayer sheet and its performance in the final multilayer glass panel product.

[0062] In an extruder, the thermoplastic raw material and plasticizer particles, including any of the above-mentioned resins, plasticizers, and other additives, are further mixed and melted to form a molten material with a generally uniform temperature and composition. In embodiments of the present invention, the melting temperature may be about 200°C. When the molten material reaches the end of the extruder, it moves into the extruder die. The extruder die is a component of the extruder that gives the final product shape to the polymer interlayer sheet. The die typically has an opening defined by a lip, where the dimension in one direction is significantly larger than the dimension in the vertical direction. Generally, the die is designed so that the molten material flows uniformly and exits the die in the final shape of the product, starting from a cylindrical shape. Multiple shapes can be imparted to the final polymer interlayer sheet by the die, as long as the shape is continuous. Generally, in its most basic sense, extrusion is a process used to produce an object with a constant cross-sectional shape. This is achieved by pushing or pulling material through a die that has the desired cross-sectional shape of the final product.

[0063] In some embodiments, a co-extrusion process may be used. Co-extrusion is a process of simultaneously extruding multiple layers of polymer material. Generally, this type of extrusion uses two or more extruders to melt different thermoplastic melts with different viscosities or other properties, and delivers them in a constant volume of extrusion to pass through a co-extrusion die to form the desired final shape. For example, the multilayer intermediate layer of the present invention (e.g., in the form of a three-layer intermediate layer) is preferably co-extruded using a multi-manifold co-extrusion apparatus that includes a manifold for a first die, a manifold for a second die, and a manifold for a third die. The co-extrusion apparatus may be operated to simultaneously extrude the polymer melt from each manifold through the die to the outside of the opening, in which case the multilayer intermediate layer is extruded as a composite of three individual polymer layers. These polymer melts may be flowed through the die such that the core layer is positioned between the surface layers to produce a three-layer intermediate layer with the core layer sandwiched between the surface layers. The die opening may include a pair of lips located on either side of the opening. Given the position and orientation of the polymer melt, the surface layers may come into contact with the lips. In any case, the thickness of the intermediate layer can be changed by adjusting the distance between the die lips located at the die opening.

[0064] In a co-extrusion process, the thickness of multiple polymer layers exiting the extrusion die can typically be controlled by adjusting the relative velocity of the molten material passing through the extrusion die and by the size of the individual die lips. According to some embodiments, the total thickness of the multilayer intermediate can be at least about 13 mils, at least about 20, at least about 25, at least about 27, at least about 30, at least about 31 mils, and / or about 75 or less, about 70 or less, about 65 or less, or about 60 or less, or in the range of about 13 to about 75 mils, about 25 to about 70 mils, or about 30 to about 60 mils. If the intermediate layer contains two or more polymer layers, the thickness of each layer can be at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10 mils, and / or about 50 or less, about 40 or less, about 30 or less, about 20 or less, about 17 or less, about 15 or less, about 13 or less, about 12 or less, about 10 or less, or about 9 mils or less. In some embodiments, each layer may have approximately the same thickness, while in other embodiments, one or more layers may have a different thickness from one or more other layers within the intermediate layer.

[0065] In some embodiments, the intermediate layer includes at least three polymer layers, one or more of the inner layers can be made relatively thin compared to the other outer layers. For example, in some embodiments, the multilayer intermediate layer is a three-layer intermediate layer, the thickness of the innermost layer can be about 12 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, about 6 or less, or about 5 mils or less, or can be in the range of about 2 to about 12 mils, about 3 to about 10 mils, or about 4 to about 9 mils. In the same or other embodiments, the thickness of each outer layer can be at least about 4, at least about 5, at least about 6, at least about 7 mils, and / or about 15 or less, about 13 or less, about 12 or less, about 10 or less, about 9 or less, or about 8 mils or less, or can be in the range of about 2 to about 15, about 3 to about 13, or about 4 to about 10 mils. If the intermediate layer includes two outer layers, the total thickness of these layers may be at least about 9, at least about 13, at least about 15, at least about 16, at least about 18, at least about 20, at least about 23, at least about 25, at least about 26, at least about 28, or at least about 30 mils and / or not exceeding about 73, not exceeding about 60, not exceeding about 50, not exceeding about 45, not exceeding about 40, not exceeding about 35 mils, or in the range of about 9 to about 70 mils, about 13 to about 40 mils, or about 25 to about 35 mils.

[0066] According to some embodiments, the ratio of the thickness of one outer layer to one inner layer in a multilayer interlayer can be at least about 1.4:1, at least about 1.5:1, at least about 1.8:1, at least about 2:1, at least about 2.5:1, at least about 2.75:1, at least about 3:1, at least about 3.25:1, at least about 3.5:1, at least about 3.75:1, or at least about 4:1. If the interlayer is a three-layer interlayer in which an inner core layer is positioned between a pair of outer surface layers, the ratio of the thickness of one surface layer to the thickness of the core layer may fall within one or more of the above ranges. In some embodiments, the ratio of the total thickness of the outer layer to the inner layer can be at least about 2.25:1, at least about 2.4:1, at least about 2.5:1, at least about 2.8:1, at least about 3:1, at least about 3.5:1, at least about 4:1, at least about 4.5:1, at least about 5:1, at least about 5.5:1, at least about 6:1, at least about 6.5:1, or at least about 7:1, and / or less than or equal to about 30:1, less than or equal to about 20:1, less than or equal to about 15:1, less than or equal to about 10:1, less than or equal to about 9:1, or less than or equal to about 8:1.

[0067] Multilayer interlayers as described herein may generally include flat interlayers whose thickness is substantially the same along the length, or longest dimension, and / or width, or second longest dimension of the sheet. On the other hand, in some embodiments, the multilayer interlayers of the present invention may be tapered or wedge-shaped interlayers that include at least one tapered region having a wedge shape. A tapered interlayer has a shape in which the thickness changes along at least a portion of the length and / or width of the sheet, for example, the thickness of at least one edge of the interlayer is greater than that of the other edge. If the interlayer is a tapered interlayer, at least one, at least two, at least three, or more of the individual resin layers may include at least one tapered region. Tapered interlayers may be particularly useful, for example, in head-up display (HUD) panels for automobiles and aircraft.

[0068] Therefore, in embodiments according to any of the above-described embodiments, the cut sheet in step a) and the cut sheet in step e) may include polyvinyl butyral with a thickness of about 0.1 mm to 1.0 mm.

[0069] In embodiments according to any of the embodiments described above, the cut sheet in step a) and the cut sheet in step e) include polyvinyl butyral with a thickness of approximately 0.2 mm to 0.8 mm.

[0070] According to the present invention, L-shaped pieces may be joined together to form a rectangular frame that defines a rectangular opening. Various methods can be used to join the materials. Methods for joining the L-shaped pieces include heat welding and solvent welding. Alternatively, they may be connected by form-fit so that they are held in place by friction.

[0071] According to the present invention, a rectangular frame may then be placed around the functional material to obtain a framed functional sheet. This can also be described as placing the functional material within the rectangular frame or within the rectangular opening defined by the frame.

[0072] According to the present invention, a functional sheet with a frame may be covered with a cut sheet to form a functional intermediate layer stack. According to the present invention, the cut sheet in step e) may be the same sheet as the cut sheet in step a), or it may be a different sheet. Therefore, the cut sheet in step e) may be the same sheet as the cut sheet in step a), or the cut sheet in step e) may be a different sheet from the cut sheet in step a).

[0073] In embodiments according to any of the above-described embodiments, the present invention may further include covering the framed switchable sheet with a further cutting sheet on the side opposite to the cutting sheet of step e). In this embodiment, the cutting sheet may be used as both the top and bottom layer for the framed switchable sheet.

[0074] In embodiments according to any of the above-described embodiments, the present invention may further include arranging rigid substrates on both sides of a switchable intermediate layer stack to form a switchable laminate. Various rigid substrates can be used, but glass is particularly suitable. Other rigid substrates may include polycarbonate, ethylene vinyl alcohol, and other thermoplastic polymers including thermoplastic ionomers.

[0075] Unless otherwise specified, all figures used in this specification and the claims to represent quantities, molecular weights, and other properties of components, reaction conditions, etc., should be understood to be modified in all cases by the term “approximately.” Unless otherwise indicated, the numerical parameters described in the following specification and the appended claims are approximations that may vary depending on the desired properties to be obtained by the present invention. At a minimum, each numerical parameter should be interpreted in light of the number of significant figures reported and by applying common rounding techniques. Furthermore, the scope described in this disclosure and the claims is intended to specifically include the entire range, not just the endpoints. For example, a range indicated as 0 to 10 is intended to disclose all integers between 0 and 10, such as 1, 2, 3, 4, etc., all decimals between 0 and 10, such as 1.5, 2.3, 4.57, 6.1113, etc., and the endpoints 0 and 10. Furthermore, the scope related to substituents of chemical substances, such as "C1-C5 diols," is intended to specifically include and disclose C1, C2, C3, C4, and C5 diols.

[0076] While the numerical ranges and parameters representing the broad scope of this invention are approximations, the numerical values ​​shown in specific examples are reported as accurately as possible. However, each numerical value inherently contains a certain degree of error that inevitably arises from the standard deviation observed in each test measurement.

[0077] When used in the specification or appended claims, the singular forms "a," "an," and "the" include multiple references unless the context explicitly states otherwise. For example, a reference to one "polyester," one "dicarboxylic acid," or one "residue" is synonymous with "at least one" or "one or more" polyesters, dicarboxylic acids, or residues, and is therefore intended to refer to both singular and plural polyesters, dicarboxylic acids, or residues. Similarly, a reference to a composition "comprising," "containing," "having," or "including" "a certain one" component or "a certain one" polyester is intended to include other components or other polyesters, respectively, in addition to the specifically identified component or residue. Therefore, the terms “containing,” “having,” and “including” are intended to be synonymous and may be used interchangeably with the term “comprising,” meaning that at least the specified compound, element, particle, or step of a method is present in the composition, article, or method, but this does not preclude the presence of other compounds, catalysts, materials, particles, or steps of a method having the same function as the specified ones, unless expressly excluded in the claim.

[0078] Furthermore, it should be understood that reference to one or more process steps does not preclude the existence of further process steps that may precede or follow the steps in the described combination, or process steps that can be explicitly identified as intervening between those steps. In addition, the written representation of process steps or components is a convenient means of identifying individual activities or components, and the written representations can be arranged in any order unless otherwise indicated.

[0079] Although the compositions of the present invention have been described in detail above with respect to two exemplary embodiments having two usefulnesses in their end use, it will be understood by those skilled in the art that the compositions of the present invention can be used in a wide variety of end uses.

[0080] The following examples illustrate suitable and / or preferred methods and results according to the present invention. However, it should be understood that these examples are provided for illustrative purposes only and should not be considered as limiting the overall scope of the invention. Unless otherwise specified, all percentages are weight percentages. [Examples]

[0081] Virtual Example 1 In this hypothetical example, the intermediate frame is formed from two L-shaped segments cut from a larger-than-usual PVB sheet (see Figure 2). The two L-shaped sections are then welded or soldered together to form a single intermediate frame, while the central portion of the larger-than-usual PVB sheet is recovered and used as the top layer to laminate the switchable film onto the glass. This approach of constructing the intermediate frame from L-shaped segments and minimizing waste is a unique approach that has not been previously considered or implemented and is not obvious to those skilled in the art.

[0082] Virtual Example 2 In this hypothetical example, the intermediate frame is formed from two L-shaped segments cut from a larger-than-usual PVB sheet (see Figure 2). The two L-shaped sections are then fitted together (joined during lamination) to form a single intermediate frame, while the central portion of the larger-than-usual PVB sheet is recovered and used as the top layer to laminate a switchable film onto the glass. This approach of constructing the intermediate frame from L-shaped segments and minimizing waste is a unique approach that has not been considered or implemented before and is not obvious to those skilled in the art.

Claims

1. A method for fabricating a functional intermediate layer stack, a) Cut out two L-shaped pieces from the corners of the bulk sheet of the intermediate layer material, leaving the cut sheet intact. b) If necessary, trim one or more of the two L-shaped pieces or the cut sheet. c) Joining the L-shaped pieces to form a rectangular frame that defines a rectangular opening, d) Obtaining a framed functional sheet by arranging the rectangular frame around the functional material, and e) The method comprising covering the framed functional sheet with a cut sheet to form the functional intermediate layer stack, wherein the cut sheet in step e) is the same sheet as the cut sheet in step a) or a different sheet.

2. The method according to claim 1, wherein the functional material comprises one or more of the following: a photopolymer material, a conductive material, a solar reflective material, a polymer-dispersed liquid crystal material, a suspended particle material, an electrochromic material, a photochromic material, or an electrochromic / photochromic material.

3. The method according to claim 1, wherein the cut sheet in step e) is the same sheet as the cut sheet in step a).

4. The method according to claim 1, wherein the cut sheet in step e) is a different sheet from the cut sheet in step a).

5. The method according to any one of claims 1 to 4, wherein the intermediate layer material is a viscoelastic polymer.

6. The method according to any one of claims 1 to 5, wherein the viscoelastic polymer comprises one or more of polyvinyl acetal, thermoplastic polyurethane, or ethylene vinyl acetate.

7. The method according to any one of claims 1 to 6, wherein the cut sheet in step a) and the cut sheet in step e) contain polyvinyl butyral having a thickness of about 0.1 mm to 1.0 mm.

8. The method according to any one of claims 1 to 7, wherein the cut sheet in step a) and the cut sheet in step e) contain polyvinyl butyral with a thickness of about 0.2 mm to 0.8 mm.

9. The method according to any one of claims 1 to 8, further comprising covering the framed switchable sheet with a further cutting sheet on the side opposite to the cutting sheet of step e).

10. The method according to any one of claims 1 to 9, further comprising arranging rigid substrates on both sides of the switchable intermediate layer stack to form a functional laminate.

11. The method according to any one of claims 1 to 10, wherein the joining of the L-shaped pieces is performed by one or more of the following: heat welding, solvent welding, or shape fitting.

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