Intermediate layer with improved gradient bands

Abstract

Polymer interlayers having improved gradient zones and laminates including these interlayers are disclosed. The polymer interlayers and laminates including the polymer interlayers have gradient zones that exhibit high levels of gradient beauty in terms of the visible light transmittance spectrum.

Description

[Technical Field]

[0001]

[0001] The present invention relates generally to polymer interlayers having improved gradient zones and laminates including these interlayers. More particularly, the present invention relates generally to polymer interlayers and laminates including polymer interlayers having gradient zones that have a high level of gradient beauty in terms of the visible light transmittance spectrum. [Background technology]

[0002]

[0002] Generally, multi-layered glass panels include an interlayer or multiple interlayers or a laminate composed of an interlayer sandwiched between two glass panes. In some applications, the laminate may include only one glass pane or other rigid substrate. Laminated multi-layered glass panels are commonly utilized in transportation vehicles (including automobiles, trucks, trains, boats, and airplanes) and other applications. Multi-layered glass panels used in transportation applications are commonly referred to as laminated safety glass. Typically, the primary function of the interlayer in laminated safety glass is to absorb energy resulting from an impact or force applied to the glass, to hold the glass layers together even when force is applied, and to prevent the glass from shattering into sharp shards in the event of glass breakage. In addition to these safety benefits, the interlayer can additionally impart a higher acoustic rating to the laminated glass, reduce UV and IR transmission, provide a gradient or shade band, and / or improve the aesthetics of the associated window.

[0003]

[0003] Typically, interlayers intended for use in laminated glass applications are generally manufactured by blending a polymeric resin, such as poly(vinyl acetal), with one or more plasticizers and melt processing the mixture into an interlayer by any applicable process or method known to those skilled in the art. Once formed, these interlayers, or multilayer interlayers, are typically wound into rolls for storage prior to later use in multilayer glass panels.

[0004] Interlayers can be incorporated into multilayer glass panels using various techniques known in the art. For example, at least one interlayer can be placed between two substrates, and excess interlayer can be trimmed from the edges to create an assembly. It is not uncommon for multiple interlayers to be placed within or between two substrates, thereby creating a multilayer stack having an outer glass panel and multiple inner polymer interlayers. Once formed, these stacks are typically processed to remove most of the interfacial air by any applicable process or method known to those skilled in the art, such as by nip rollers, vacuum bags, vacuum rings, or another suitable degassing mechanism. Additionally, the interlayers can be partially pressed to the substrates by any method known to those skilled in the art. In the final step, the interfacial bond created during the degassing operation is typically made more permanent by a high-temperature and / or high-pressure lamination process, some of which are known to those skilled in the art, such as, but not limited to, autoclaving.

[0005]

[0005] A popular option for automobiles is a windshield or windshield whose upper region has a tinted gradient (or shade) band that reduces the intensity of sunlight that strikes the driver and front passenger through that portion of the windshield, the tinted gradient band shade fading gradually to the predominant hue of the remainder of the windshield.

[0006]

[0006] Interlayers containing gradient bands can be produced in several different ways. U.S. Pat. No. 4,316,868 discloses a method and apparatus for producing colored gradient bands in extruded thermoplastic sheets. In this method, a probe is inserted into a sheet extrusion die manifold, and a colored melt is injected into the polymer melt, resulting in a sheet with colored bands. U.S. Pat. No. 8,945,446 discloses a method in which a gradient or colored layer is extruded by a secondary extruder. In this method, a molten colored resin composition passes through individually installed channels inside the extrusion die, forming an interlayer surrounded by an outer layer. Alternatively, colored bands on thermoplastic sheet materials can be obtained by applying ink material to the sheet surface under appropriately controlled conditions. Techniques that have been used include printing, dipping, and spraying using a variety of equipment. In addition, coextrusion of colored and clear plastics can be used to produce gradient interlayers.

[0007] Current techniques for producing interlayers with gradient bands typically involve coextrusion of a colored polymer and a clear polymer. Some coextrusion techniques are difficult to control in practice, especially when a gradient color band, such as that desired for use in interlayers for automobile windshields, is the goal. Consistent quality, with no color change apart from a gradual decrease in optical density toward the cutoff region, is a characteristic requirement for such interlayers. Furthermore, the location of the cutoff must be consistent across the sheet. Therefore, variations in the polymer melt flow through the extrusion device must be avoided. This creates very difficult control problems.

[0008]

[0008] A characteristic requirement for such interlayers is a consistent quality without any color change apart from a gradual decrease in optical density toward the cutoff region, which also determines the visual aesthetics. The gradient bands can have different appearances and visual aesthetics based on the shape of their visible light transmittance spectrum. Additionally, optical illusions known as "Mach bands" appear on the transparent side of the cutoff. The distinctness of the Mach bands, in terms of sharpness and / or width, can be visually unattractive.

[0009]

[0009] Through the available technologies described above, the target transmittance spectrum of an interlayer can be easily designed and conveniently manufactured to reflect the desired shape of the spectrum. Attempts have been made to change the shape of the visible light transmittance spectrum, particularly in the fade-off range between the dark plateau and the cutoff, but with limited success. For example, controlling the fade-off distance to be either shorter or longer than usual, diffusing the colorant into the adjacent transparent layer(s), and utilizing the diffusion phenomenon are commonly used means to improve gradient aesthetics. None of these methods result in laminated glass containing such an interlayer having a gradient band with a high level of gradient aesthetics in terms of the visible light transmittance spectrum. Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there is a need for an interlayer having an improved gradient zone and a method of making an interlayer that is relatively easy to control and that can result in a uniform gradient zone. [Means for solving the problem]

[0011]

[0011] The present invention generally relates to an intermediate layer having a gradient band that exhibits excellent properties and provides desirable optical properties when incorporated into a laminate such as a front glass. The present invention generally relates to a laminate including a polymer intermediate layer and a polymer intermediate layer having a gradient band with a high level of gradient beauty from the viewpoint of the visible light transmittance spectrum.

[0012]

[0012] In one embodiment, the intermediate layer having improved gradient quality includes: a first layer having a transparent portion and a gradient color band portion, the gradient color band portion is encapsulated within the transparent portion, and the gradient color band portion has a cut-off X at the start of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D which is the distance from X to Y, and a distance d which is the distance from Y to Z, and the distance D of the gradient portion satisfies the following formula: 22.9 mm < D < 38.1 mm and D / d < 2.00.

[0013]

[0013] In one embodiment, a method of making an intermediate layer having improved gradient quality comprises: (a) providing a sheet extrusion die having an orifice and a manifold adapted to supply a polymer melt to the orifice through an extrusion passage; (b) providing a probe located within the manifold and adjacent to the extrusion passage, the probe having an extrusion orifice extending parallel to the probe axis on a surface adjacent to the extrusion passage, the probe being located such that when the main stream of the thermoplastic polymer is supplied to the manifold and extruded through the slit die via the extrusion passage, the streamlines of the main stream pass by the probe orifice in a location that is substantially parallel and in the extrusion direction; (c) supplying a main stream of molten thermoplastic polymer to the manifold and a colored secondary stream of molten thermoplastic polymer to the probe at substantially the same temperature and viscosity; (d) simultaneously extruding both streams such that a layer of colored polymer having a constant width but a thickness that gradually tapers at one end of the width is completely encapsulated within the main stream of molten polymer; (e) extruding the integrated stream through the slit die to produce a sheet having an encapsulated gradient color band portion, the gradient color band portion having a cut-off X at the start of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D that is the distance from X to Y, and a distance d that is the distance from Y to Z, and the distance D of the gradient portion satisfies the following formula: 22.9 mm < D < 38.1 mm and D / d < 2.00.

[0014]

[0014] In another embodiment, the present invention includes an intermediate layer manufactured by the aforementioned method.

[0015] In another embodiment, the front glass includes a first glass substrate, the aforementioned intermediate layer, and a second glass substrate.

[0015] [[ID=?]]

[0016] Embodiments of the present invention are described herein in connection with the following figures.

Brief Description of the Drawings

[0016]

Figure 1

[0017] FIG. 1 is a simplified diagram of the transmittance spectrum of laminated glass containing gradient bands.

Figure 2

[0018] 1 is a graph showing % transmission over a gradient band for Example 1.

Figure 3

[0019] 1 is a graph showing % transmission over a gradient band for Example 2.

Figure 4

[0020] 1 is a graph showing % transmission over a gradient band for Comparative Example 1.

Figure 5

[0021] 10 is a graph showing % transmission over a gradient band for Comparative Example 2.

Figure 6

[0022] 10 is a graph showing % transmission over a gradient band for Comparative Example 3.

Figure 7

[0023] 10 is a graph showing % transmission over a gradient band for Comparative Example 4.

Figure 8

[0024] 10 is a graph showing % transmission over a gradient band for Comparative Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0017]

[0025] The present invention relates generally to interlayers having improved gradient bands that provide desirable optical properties when incorporated into laminates such as windshields. The interlayers have improved optical quality. More particularly, the present invention relates generally to polymer interlayers having color or gradient bands with improved gradient aesthetics and good Mach band quality.

[0018]

[0026] As described further below, it has been discovered that interlayers having gradient bands can be successfully manufactured when specific parameters for creating the gradient bands are used. Specifically, the present invention discloses what is needed to achieve a high level of gradient aesthetics in terms of the visible light transmittance spectrum in laminated glass containing such interlayers.

[0019]

[0027] FIG. 1 schematically shows the aspect of the transmittance spectrum of laminated glass containing a gradient band. Regarding FIG. 1, the cut-off is the starting point of the gradient band and the point where the thickness of the colored layer becomes zero. The cut-off may be referred to as point X. The dark plateau part is the region where the transmittance reaches its lowest level. In FIG. 1, D is the distance from the cut-off to the point (which may be referred to as point Y) where the transmittance reaches 40%, and d is the distance from the point (which may be referred to as point Z) where the transmittance reaches 70% to the point where the transmittance reaches 40%. Both D and d are defined as means for describing the fade-off distance between the dark plateau part and the cut-off. When defining the distances D and d using points X, Y, and Z, the distance D is equal to the distance from X to Y, and the distance d is equal to the distance from Y to Z.

[0020]

[0028] Based on a plurality of experiments using gradient intermediate layers and analysis of transmittance spectra, the inventors of the present invention have determined that for a gradient band having a width of about 10 to 102 centimeters (cm) (about 4 to 40 inches), when the following conditions are satisfied, regardless of how the gradient band is manufactured and whether the sheet containing the gradient band is integral or multilayer, the gradient beauty is optimized. The conditions that need to be satisfied to manufacture a gradient band having improved gradient beauty are as follows: 1) 22.9 mm < D < 38.1 mm (0.90 inch < D < 1.5 inches); 2) D / d < 2.00; and 3) the color is only present in one layer and is visible, and there is no visible diffusion of the color to adjacent layer(s).

[0021]

[0029] When D is less than about 22.9 mm, the transition from the dark plateau region to the cut-off is not smooth, degrading the visual quality of the gradient band and often resulting in sharper and / or brighter Mach bands on the transparent side of the cut-off. As used herein, a Mach band is defined as a visual "defect" that is an optical illusion resulting from spatial high-boost filtering by the human visual system on the luminance channel of the image captured by the retina. It causes end detection in the human visual system, exaggerating the contrast between the ends of slightly different shades of a particular color, such as blue, as soon as they are adjacent to each other. The presence of sharper or brighter Mach bands is unpleasant for consumers. When D is greater than about 38.1 mm, the transition from the dark plateau region to the cut-off is too wide and also adversely affects the quality, particularly the beauty, of the gradient band. In embodiments, it is more desirable when 23.2 mm < D < 37.5 mm, or 23.4 mm < D < 37.0 mm, or 23.6 mm < D < 36.5 mm, or 23.8 mm < D < 36.0 mm, or 24.0 mm < D < 36.5 mm, or 24.2 mm < D < 36.0 mm, or 24.4 mm < D < 35.5 mm, or 24.5 mm < D < 35.0 mm, or 24.6 mm < D < 34.5 mm, or 24.7 mm < D < 34.0 mm, or 24.8 mm < D < 33.5 mm, or 24.9 mm < D < 33.0 mm, or 25.0 mm < D < 32.5 mm, or 25.1 mm < D < 32.0 mm, or 25.2 mm < D < 31.5 mm, or 25.3 mm < D < 31.0 mm, or 25.4 mm < D < 30.5 mm (1.0 inch < D < 1.2 inches). In embodiments, D is greater than 22.9, or greater than 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25.0, 25.1, 25.2, 25.3, or greater than 25.4.In embodiments, D is less than 38.1, 38.0, 37.9, 37.8, 37.7, 37.6, 37.5, 37.4, 37.3, 37.2, 37.1, 37.0, 36.9, 36.8, 36.7, 36.6, 36.5, 36.4, 36.3, 36.2, 36.1, 36.0, 35.9, 35.8, 35.7, 35.6, 35.5, 35.4, 35.3, 35.2, 35.1, 35.0, 34.9, 34.8, 34.7, 34.6, 34.5, 34.4, 34.5, 34.6, 34.7, 34.8, 34.9 ... Less than 4.3, 34.2, 34.1, 34.0, 33.9, 33.8, 33.7, 33.6, 33.5, 33.4, 33.3, 33.2, 33.1, 33.0, 33.9, 32.8, 32.7, 32.6, 32.5, 32.4, 32.3, 32.2, 32.1, 32.0, 31.9, 31.8, 31.7, 31.6, 31.5, 31.4, 31.3, 31.2, 31.1, 31.0, 30.9, 30.8, 30.7, 30.6, or less than 30.5.

[0022]

[0030] Another important factor in gradient quality is the ratio D / d. In embodiments, the ratio D / d is less than 2.00, or less than 1.99, or less than 1.98, or less than 1.97, or less than 1.96, or less than 1.95. If D / d is greater than 2.00, the overall gradient quality decreases, and the transmission spectrum approaching the cutoff may become steeper. Additionally, the Mach band becomes more distinct on the transparent side of the cutoff, and the Mach band quality deteriorates. In embodiments, D / d is at least 1.50, or at least 1.60, or at least 1.70, or at least 1.80. In embodiments, it is even more desirable for D / d to be between 1.80 and 1.99.

[0023]

[0031] It is important that the colorant used to form the gradient band in the interlayer must remain in a single, unique layer without visible diffusion into an adjacent "clear" layer or layers. Here, "layer" includes a clear layer encapsulating the gradient band, if the gradient is enabled by the use of a probe such as that disclosed in U.S. Pat. No. 4,316,868. Such diffusion of colorant into adjacent layer(s) can make it more difficult to maintain uniformity of the gradient band in the sheet extrusion (or machine) direction, resulting in quality issues such as unevenness within the gradient band.

[0024]

[0032] Generally, the method used to manufacture an interlayer having gradient bands includes the steps of: (a) providing a sheet extrusion die having a slit die orifice and a manifold adapted to feed a polymer melt to said orifice through an extrusion passage; (b) providing a generally torpedo-shaped probe eccentrically located within the manifold and adjacent to the extrusion passage, the probe axis being parallel to the slit die orifice, the probe having a wedge-shaped extrusion orifice on a surface adjacent to the extrusion passage and extending parallel to the probe axis for less than half the width of the extrusion passage, wherein a thermoplastic polymer is fed into the manifold and through the extrusion passage. (c) supplying a main stream of molten thermoplastic polymer to the manifold and a colored secondary stream of the same polymer at substantially the same temperature and viscosity to the probe; (d) simultaneously extruding the two streams so that a layer of colored polymer having a constant width is completely encapsulated in the main stream of molten polymer supplied to the extrusion manifold; and (e) extruding the combined streams through the slit die to produce a sheet having gradient color bands.

[0025]

[0033] The probe configuration is designed so that the streamlines of the main polymer stream remain substantially parallel and in the extrusion direction as they pass by the extrusion orifice in the probe. The critical portion of the probe is the portion with the wedge-shaped extrusion orifice, because non-parallel streamlines at that point tend to distort the shape of the colored extrusion band. Therefore, it is desirable for the probe to be shaped so that the orifice is as close as possible to the extrusion passage without forming a blockage at that point. Probe configurations that provide specific dark plateaus and cutoffs, such as those for D and D / d as previously disclosed, are particularly preferred. By having a probe that provides the required dark plateaus and cutoffs, an interlayer with improved gradient aesthetics can be produced.

[0026]

[0034] The orifices in the probe may be wedge-shaped, but this is not intended to imply that the orifices necessarily have a triangular configuration. In a preferred configuration, the orifice thickness is constant across much of its width before tapering at one end. The tapering can be linear, but more frequently, the tapering is shaped to provide a color fade, which, if observed in the finished sheet as a gradient band, is aesthetically more pleasing and meets the aforementioned criteria. The orifices generally have a width shorter than the length of the probe. The orifices often extend 30-50% of the probe's total length within the manifold, producing a color band that is less than half the width of the extruded sheet, preferably 5-30% of that width. The probe is positioned in the manifold so that the main flow streamlines are substantially parallel and in the direction of extrusion as they pass by the wedge-shaped extrusion orifices in the probe.

[0027]

[0035] When a main flow is fed through a feed pipe into a manifold that communicates with a slit die orifice through an extrusion passage, the flow lines initially diverge from the feed pipe so that the polymer spreads and fills the manifold. However, conventional slit die extrusion equipment is designed so that the extruded polymer flows through the extrusion passage, with the polymer flowing at substantially the same speed across its entire width, i.e., so that the flow lines of the polymer in the extrusion passage are substantially parallel and in the direction of extrusion. Parallel flow is then achieved near the entrance of the extrusion passage, as appropriate and as described above, which is the preferred location for the probe orifice.

[0028]

[0036] In practice, the probe can extend up to 75%, or preferably up to 25%, of the width of the extrusion channel. A preferred configuration places the narrowest point of the wedge-shaped orifice adjacent the probe tip, which results in a polymer sheet having, when viewed from above, a color band whose greatest density is adjacent the edge of the sheet and fades off toward the center of the sheet. Such a sheet is ideally configured for the production of automotive windshield interlayers.

[0029]

[0037] The temperature and viscosity of the colored melt extruded through the probe is substantially the same as that of the main stream fed to the manifold, however, this is intended to encompass up to a 10% variation in temperature and viscosity between the two streams without significant adverse effects.

[0030]

[0038] However, the velocities of the two streams at the point of initial contact may be significantly different, if desired. It has been found that if the colored secondary melt stream is extruded at a faster rate, a thicker band is obtained when the speeds are matched. A thicker band is often advantageous because it allows a lower color density melt to be used to achieve the same color density in the resulting sheet. Therefore, a preferred feature of the present invention is to extrude the colored secondary melt stream at a rate up to 12 times, and preferably 5 to 10 times, the rate of the main polymer melt stream when it first contacts the colored melt. The resulting gradient band may exhibit a thickness of 15 to 95%, preferably 60 to 90%, of the total thickness of the sheet at its thickest point.

[0031]

[0039] The main stream feeding the manifold may also be colored, but an important objective of the present invention would not be achieved if both the main stream and the colored secondary stream were colored to the same concentration. Therefore, it is preferred that the main stream be clear or of a substantially lower color concentration than the stream feeding the probe.

[0032]

[0040] As used herein, the term "interlayer" refers to a single or multi-layer polymer sheet that may be suitable for use with at least one rigid substrate to form a multi-layer panel. The terms "single-sheet" and "monolithic" interlayer refer to an interlayer formed from one single sheet, while the terms "multi-layer" and "multi-layer" interlayer refer to an interlayer having two or more sheets coextruded, assembled, laminated, or otherwise combined with one another.

[0033]

[0041] The term "multilayer interlayer" refers to a polymer interlayer comprising at least two polymer layers. As discussed further below, the multiple layers may be separately extruded layers, coextruded layers, or any combination of separately extruded and coextruded layers. Thus, a multilayer interlayer may include, for example, two or more single-layer interlayers combined together (a "multilayer interlayer"); two or more layers coextruded together (a "coextruded interlayer"); two or more coextruded interlayers combined together; a combination of at least one single-layer interlayer and at least one coextruded interlayer; and a combination of at least one multilayer interlayer and at least one coextruded interlayer.

[0034]

[0042] As described above, the polymer layers or interlayers can be used to form multi-layer interlayers and laminates, such as windshields or other laminated glass panels, that are useful in many applications. In various embodiments, although interlayers comprising poly(vinyl acetal) are described herein, these polymer layers can be formed from thermoplastic resins such as ethylene vinyl acetate, thermoplastic polyurethanes, ionomers, poly(vinyl acetal), and mixtures thereof.

[0035]

[0043] Generally, the polymer layer can comprise at least 1, at least 2, at least 3, at least 4, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 weight percent of one or more thermoplastic resins, based on the total weight of the polymer layer. Additionally or alternatively, the polymer layer can comprise no more than 99, no more than 95, no more than 90, no more than 80, no more than 70, no more than 60, or no more than 50 weight percent of one or more thermoplastic resins, based on the total weight of the polymer layer, although other amounts can be used if desired.

[0036]

[0044] In various embodiments, the layers or intermediate layers described herein may include at least two polymer layers (e.g., a single layer or coextruded multiple layers) disposed in direct contact with one another. When three or more layers are utilized in a multilayered intermediate layer, some layers may be referred to as skin layers, and one or more layers may be referred to as core layers. As used herein, "skin layer" generally refers to the outer layer of the intermediate layer, and "one or more core layers" generally refers to the inner layer or layers disposed between the skin layers. At least one surface of the core layer may be in direct contact with at least one surface of the skin layer, or may be in indirect contact with the skin layer through a tie layer, coating, or adhesive.

[0037]

[0045] Exemplary layer arrangements for multi-layer interlayer embodiments include: skin / core / skin, skin / core, skin / core / core / skin, and skin / core / core / core / skin, although other embodiments are possible as well, as known to those skilled in the art.

[0038]

[0046] The multilayer interlayers described herein can also have more than three layers (e.g., at least four, at least five, at least six, or up to ten or more individual layers). In various embodiments, the multilayer interlayer structures can contain two, three, four, or more polymer layers, two or more of which may be in direct contact with each other or with other types of layers. The layers can have a variety of thicknesses, which are determined primarily by the type of interlayer or laminate in which the layer is being used, and can be any desired thickness.

[0039]

[0047] In various embodiments, the thickness, or gauge, of any layer or interlayer can be at least about 0.5 mil, at least about 1, 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 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60 mils or more, depending on the desired properties and application. In millimeters, the thickness of the polymer layer or intermediate layer can be at least about 0.025, at least about 0.05, at least about 0.075, at least about 0.10, at least about 0.125, at least about 0.150, at least about 0.175, at least about 0.20, at least about 0.225, at least about 0.25, at least about 0.38, at least about 0.51, at least about 0.64, at least about 0.76, at least about 0.89, at least about 1.02, at least about 1.15, at least about 1.28, at least about 1.52 mils or more.

[0040]

[0048] The polymer layers described herein may further comprise at least one plasticizer. Depending on the specific composition of the thermoplastic resin forming the polymer layer, the plasticizer may be present in an amount of at least 1, at least 2, at least 3, at least 4, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, or at least 60 phr or more. In embodiments, the amount of plasticizer may be 120 or less, 110 or less, 105 or less, 100 or less, 95 or less, 90 or less, 85 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, or 40 or less phr, although other amounts may be used depending on the specific material and desired properties.

[0041]

[0049] In various embodiments, the intermediate layer can contain at least 2, at least 5, at least 8, at least 10, at least 13, at least 15, at least 18, or at least 20 weight percent or more of at least one plasticizer, based on the weight of the polymer layer. Additionally or alternatively, the polymer can contain up to 100, up to 80, up to 70, up to 60, up to 50, up to 40, up to 30, up to 25, or up to 20 weight percent of at least one plasticizer, based on the weight of the polymer layer.

[0042]

[0050] If a plasticizer is used, the plasticizer(s) can be any known in the art. The plasticizer can be either monomeric or polymeric in structure. In various embodiments, the plasticizer can be a compound having 30 or fewer, 25 or fewer, 20 or fewer, 15 or fewer, 12 or fewer, or 10 or fewer carbon atoms and a hydrocarbon segment of at least 6 carbon atoms. Suitable conventional plasticizers for use in these intermediate layers include, for example, esters of polybasic acids or polyhydric alcohols, among others. Suitable plasticizers include, for example, triethylene glycol di-(2-ethylhexanoate) ("3GEH"), triethylene glycol di-(2-ethylbutyrate), triethylene glycol diheptanoate, tetraethylene glycol diheptanoate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, butyl ricinoleate, castor oil, dibutoxyethyl phthalate, diethyl phthalate, dibutyl phthalate, trioctyl phosphate, triethyl glycol ester of coconut oil fatty acid, phenyl ether of polyethylene oxide rosin derivative, oil-modified sebacic acid alkyd resin, tricresyl phosphate, and mixtures thereof. In certain embodiments, the plasticizer is 3GEH.

[0043]

[0051] In addition, other plasticizers, such as high refractive index plasticizers, may also be used, either alone or in combination with another plasticizer. As used herein, the term "high refractive index plasticizer" refers to a plasticizer having a refractive index of at least 1.460. High refractive index plasticizers can increase or decrease the refractive index of one or more layers and improve the optical properties of interlayers, including mottle, haze, and / or transparency. In embodiments, high RI plasticizers suitable for use may have a refractive index, measured as described above, of at least 1.460, at least 1.470, at least 1.480, at least 1.490, at least 1.500, at least 1.510, at least 1.520, and / or 1.600 or less, 1.575 or less, or 1.550 or less.

[0044]

[0052] When the resin layer or intermediate layer contains a high RI plasticizer, the plasticizer can be present alone in the layer or can be blended with one or more additional plasticizers. Examples of types or classes of high refractive index plasticizers can include, but are not limited to, polyadipates (RI of 1.460 to 1.485); epoxides such as epoxidized soybean oil (RI of 1.460 to 1.480); phthalates and terephthalates (RI of 1.480 to 1.540); benzoates and toluates (RI of 1.480 to 1.550); and other specialty plasticizers (RI of 1.490 to 1.520). Specific examples of suitable RI plasticizers are dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, polypropylene glycol dibenzoate, isodecyl benzoate, 2-ethylhexyl benzoate, diethylene glycol benzoate, butoxyethyl benzoate, butoxyethyoxyethyl benzoate, butoxyethoxyethoxyethyl benzoate, propylene glycol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol ... The high RI plasticizer may include, but is not limited to, dibenzoate 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, bis-phenol A bis(2-ethylhexanoate), di-(butoxyethyl) terephthalate, di-(butoxyethyoxyethyl) terephthalate, and mixtures thereof. In embodiments, the high RI plasticizer may be selected from dipropylene glycol dibenzoate and tripropylene glycol dibenzoate, and / or 2,2,4-trimethyl-1,3-pentanediol dibenzoate. In various embodiments, the plasticizer can be selected from at least one of the following: benzoates, phthalates, phosphates, arylene-bis(diarylphosphates), and isophthalates.

[0045]

[0053] Other useful plasticizers include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl-tri-n-butyl citrate, and acetyl-tri-n-(2-ethylhexyl) citrate.

[0046]

[0054] Mixtures of plasticizers may also be used. For example, a mixture of a high refractive index plasticizer and a conventional plasticizer may be used. Alternatively, two or more conventional and / or high refractive index plasticizers may be used alone or together with other plasticizers.

[0047]

[0055] In various embodiments, the polymer layers described herein can comprise, consist essentially of, or consist of a poly(vinyl acetal) resin, such as polyvinyl butyral. Poly(vinyl acetal) layers can be used in conjunction with other polymer layers described herein to produce various types of multi-layer interlayers.

[0048]

[0056] Poly(vinyl acetal) resins can be produced and formed by acetalization of poly(vinyl alcohol) with one or more aldehydes in the presence of a catalyst according to known methods, such as those described in, for example, U.S. Pat. Nos. 2,282,057 and 2,282,026, as well as Wade, B. 2016, Vinyl Acetal Polymers, Encyclopedia of Polymer Science and Technology, pp. 1-22 (online, Copyright 2016 John Wiley & Sons, Inc.).

[0049]

[0057] Poly(vinyl acetal) resins typically have residual hydroxyl content, ester content, and acetal content. As used herein, residual hydroxyl content (calculated as PVOH) refers to the weight percent of the hydroxyl groups remaining on the polymer chain. For example, poly(vinyl acetal) can be produced by hydrolyzing poly(vinyl acetate) to PVOH and then reacting the PVOH with an aldehyde, such as butyraldehyde or propionaldehyde, preferably butyraldehyde, to produce a polymer with repeating vinyl butyral units. In the hydrolysis process of poly(vinyl acetate), typically, not all of the acetate side groups are converted to hydroxyl groups. For example, reaction with butyraldehyde typically does not result in the conversion of all of the hydroxyl groups on the PVOH to acetal groups. Thus, in any finished polyvinyl butyral, there will typically be residual ester groups, such as acetate groups (as vinyl acetate groups) and residual hydroxyl groups (as vinyl hydroxyl groups) as side groups on the polymer chain, as well as acetal (e.g., butyral) groups (as vinyl acetal groups). As used herein, residual hydroxyl content is measured on a weight percent basis according to ASTM 1396.

[0050]

[0058] In various embodiments, the poly(vinyl acetal) resin comprises a polyvinyl butyral resin, also referred to interchangeably herein as "PVB." An example polyvinyl butyral structure is used to further illustrate how the weight percentages are based on the moieties attached to the associated pendant groups:

[0051] [ka]

[0052]

[0059] Considering polyvinyl butyral of the above structure, the butyral or acetal content is based on the weight percentage of units A in the polymer, the OH content is based on the weight percentage of units B (polyvinyl OH moieties or PVOH) in the polymer, and the acetate or ester content is based on the weight percentage of units C in the polymer.

[0053]

[0060] The hydroxyl group content of the poly(vinyl acetal) resin is not particularly limited, but suitable amounts are at least 6, at least 8, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, or at least 17, in each case up to 35 weight percent or more of PVOH. In some embodiments, the poly(vinyl acetal) can have a residual hydroxyl content of less than 15 weight percent, or less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, or less than 8 weight percent. Generally, poly(vinyl acetal) resins with a lower hydroxyl weight percentage are capable of absorbing more plasticizer and absorbing plasticizer more efficiently.

[0054]

[0061] The poly(vinyl acetal) resin may also contain no more than 20 weight percent, no more than 17 weight percent, no more than 15 weight percent, no more than 13 weight percent, no more than 11 weight percent, no more than 9 weight percent, no more than 7 weight percent, no more than 5 weight percent, or no more than 4 weight percent residual ester groups, calculated as polyvinyl esters such as, for example, acetate, with the remainder being acetals such as butyraldehyde acetal, optionally including small amounts of other acetal groups such as, for example, 2-ethylhexanal groups (see U.S. Pat. No. 5,137,954). As with the residual hydroxyl group measurement, the weight percent of residual ester groups (i.e., residual acetate content) is based on the portion of the polymer backbone that is bonded to acetate groups, including pendant acetate groups.

[0055]

[0062] Poly(vinyl acetal) resins used in the present invention may also have an acetal content of at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 weight percent or more. Additionally or alternatively, the acetal content may be up to 94, up to 93, up to 92, up to 91, up to 90, up to 89, up to 88, up to 86, up to 85, up to 84, up to 83, up to 82, up to 80, up to 78, up to 77, up to 75, up to 70, or up to 65 weight percent.

[0056]

[0063] The acetal groups in the poly(vinyl acetal) resin can include vinyl propynyl or vinyl butyral groups. In one or more embodiments, the acetal groups include vinyl propynyl groups. In some embodiments, the poly(vinyl acetal) resin can include any aldehyde residue, and in some embodiments, at least one C4-C8 aldehyde residue. Examples of suitable C4-C8 aldehydes can include, for example, n-butyraldehyde, i-butyraldehyde, 2-methylvaleraldehyde, n-hexylaldehyde, 2-ethylhexylaldehyde, n-octylaldehyde, and combinations thereof. One or more poly(vinyl acetal) resins utilized in the layers and interlayers described herein may comprise a residual content of at least one C4-C8 aldehyde of at least 20, at least 30, at least 40, at least 50, at least 60, or at least 70 weight percent or more, based on the total weight of the aldehyde residuals of the resin. Alternatively, or additionally, the poly(vinyl acetal) resin may comprise no more than 99, no more than 90, no more than 85, no more than 80, no more than 75, no more than 70, or no more than 65 weight percent of at least one C4-C8 aldehyde. The C4-C8 aldehyde may be selected from the group listed above or may be selected from the group consisting of n-butyraldehyde, i-butyraldehyde, 2-ethylhexylaldehyde, and combinations thereof.

[0057]

[0064] The weight average molecular weight of the poly(vinyl acetal) resin is not particularly limited. The poly(vinyl acetal) resin has a weight average molecular weight (M) of at least 20,000, at least 30,000, at least 40,000, at least 50,000, at least 60,000, or at least 70,000. w ), with no particular upper limit. Molecular weights up to substantially 300,000 daltons are generally suitable, although higher molecular weights may be used in some cases, in each case as determined by size exclusion chromatography using the low-angle laser light scattering (SEC / LALLS) method of Cotts and Ouano in tetrahydrofuran, as described below.

[0058]

[0065] Multilayer interlayers containing multiple layers, such as one or more poly(vinyl acetal) layers, can be manufactured using any method known in the art. For example, each layer can be formed separately using techniques known in the art and then laminated together. Alternatively, multilayer interlayers can be manufactured via coextrusion.

[0059]

[0066] In various embodiments, the interlayer can be an acoustic conditioning interlayer. Polymers that exhibit one set of desirable properties, such as acoustic conditioning performance, often lack other desirable properties, such as impact resistance or strength. Therefore, to achieve a desired combination of properties, a multilayered interlayer can be produced containing a poly(vinyl acetal) layer that exhibits desirable acoustic conditioning performance and one or more other polymer layers that provide impact strength and resistance. In one or more embodiments, the acoustic conditioning interlayer can contain a poly(vinyl acetal) layer that has a Tg of at least -30, at least -25, at least -20, at least -15, at least -10, at least -5, or at least 0°C and / or less than 40, 30, 25, 20, 15, 10, or 5°C.

[0060]

[0067] Additionally, in various embodiments, the poly(vinyl acetal) layer or interlayer may exhibit enhanced acoustic control properties, such as improved loss tangent, compared to, for example, an equivalent poly(vinyl n-butyral) resin layer. The loss tangent is the ratio of a specimen's loss modulus in Pascals (G") to its storage modulus in Pascals (G'), as measured by dynamic mechanical thermal analysis (DMTA). DMTA is performed in shear mode using a vibration frequency of 1 Hz and a temperature sweep rate of 3°C / min. The peak value of the G" / G' curve at the glass transition temperature is the loss tangent value. A higher loss tangent value indicates higher damping, which can translate to better sound deadening or acoustic control performance.

[0061]

[0068] Interlayers according to various embodiments of the present invention can be made by any suitable process known to those skilled in the art of manufacturing interlayers, without limitation to the manufacturing method. For example, it is contemplated that a layer or interlayer can be formed by extrusion or coextrusion by inserting a probe into a die as described above. In an extrusion process, one or more thermoplastic resins, a plasticizer, and optionally one or more additives described above can be premixed and fed into an extrusion device. The extrusion device is configured to impart a specific shape to the thermoplastic composition to create an extruded sheet. The extruded sheet, which is generally highly viscous at elevated temperatures, can then be cooled to form a polymer sheet. Once the sheet is cooled and set, it can be cut and rolled for subsequent storage, transportation, and / or use as an interlayer.

[0062]

[0069] Coextrusion is a process in which multiple layers of polymeric materials are extruded simultaneously. Typically, this type of extrusion utilizes two or more extruders to melt and deliver a steady volumetric throughput of various thermoplastic melts of different viscosities or other properties through a coextrusion die to a desired final form. The thickness of the multiple polymer layers exiting the extrusion die in a coextrusion process can generally be controlled by adjusting the relative speed of the melts through the extrusion die and by the size of the individual extruders processing each molten thermoplastic resin material. The extrusion process can occur at temperatures known to those skilled in the art, depending on the material and application.

[0063]

[0070] Alternatively, each layer of the interlayer may be separately formed or extruded into a sheet, the sheets stacked to form a laminate structure in the desired order, and then compressed under heat and pressure to form the multi-layer interlayer. In various embodiments of the present invention, the layers or interlayers may be formed by extrusion or coextrusion. In an extrusion process, one or more thermoplastic polymers, a plasticizer, and optionally at least one additive may be premixed and fed into an extrusion apparatus, and the layer or interlayer may be melted and extruded through a die, thereby providing an extruded sheet. Alternatively, one or more layers may be purchased or manufactured separately using processes known in the art.

[0064]

[0071] As previously mentioned, the gradient or color band is coextruded with at least one other layer of polymer. In embodiments, the gradient band may be coextruded onto one outer layer of a multi-layer interlayer, such as the three-layer interlayer previously described.

[0065]

[0072] Other additives may be incorporated into any one of the above layers used to form the laminate or interlayer to improve the performance of the final product or to impart certain additional properties to the interlayer. Such additives include, but are not limited to, ACA, antiblocking agents, dyes, pigments, stabilizers (e.g., UV stabilizers), antioxidants, flame retardants, IR absorbers or blockers (e.g., indium tin oxide, antimony tin oxide, lanthanum hexaboride (LaB6), and cesium tungsten oxide), processing aids, flow additives, lubricants, impact modifiers, nucleating agents, heat stabilizers, UV absorbers, dispersants, surfactants, chelating agents, coupling agents, adhesives, primers, reinforcing additives, and fillers, among other additives known to those skilled in the art.

[0066]

[0073] Additives in liquid, powder, or pellet form are often used and can be mixed into the thermoplastic resin or plasticizer before it reaches the extruder unit or in combination with the thermoplastic resin in the extruder unit. These additives are incorporated into the composition and the resulting interlayer to enhance certain properties of the interlayer and its performance in multilayer glass panel products.

[0067]

[0074] The interlayers can be used in many applications, such as laminates or panels (such as windshields or other vehicle windows) that include one or more rigid substrates. The layers described herein and panels made with the interlayers, such as glass panels that include the interlayer laminated between two glass substrates, can have good optical clarity. The transparency of an interlayer laminated between glass substrates can be determined by measuring the haze value, which is a quantification of the light that is not transmitted through a sheet glass panel containing a multilayer interlayer. Percent haze can be measured according to the following technique: A haze meter, Model D25, is available from Hunter Associates (Reston, Va.) and can be used in accordance with ASTM D1003-61 (reapproved in 1977) - Procedure A, using Illuminant C at a 2-degree observation angle. In various embodiments, such as front glass, the interlayers described herein may exhibit a haze of less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, less than 1.5, less than 1, less than 0.75, or less than 0.5 percent, as measured in accordance with ASTM D1003-61. In other embodiments, optical properties may be less important, or higher haze levels may be desirable or acceptable where lower clarity is desired.

[0068]

[0075] Another parameter used to determine optical performance is percent transmittance (% Transmittance) or transmittance spectrum. Transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source for laminated glass samples, moving every 0.5 seconds on the sample stage from the dark plateau to cutoff (as described above and shown in Figure 1) at 3.0 mm / s. The values provided herein were obtained by analyzing polymer samples laminated between two sheets of clear glass (commercially available from Pittsburgh Glass Works, Pennsylvania), each 2.3 mm thick.

[0069]

[0076] Interlayers according to embodiments of the present invention can be used in multi-layer panels or laminates that include at least one rigid substrate. Any suitable rigid substrate may be used, and in some embodiments, may be selected from the group consisting of glass, polycarbonate, biaxially oriented PET, copolyester, acrylic, and combinations thereof. When the rigid substrate includes a polymeric material, the polymeric material may or may not include a hard-coat surface layer. In some embodiments, the multi-layer panel or laminate includes a pair of rigid substrates with a resin interlayer disposed therebetween.

[0070]

[0077] In various embodiments, the interlayers of the present invention are most commonly utilized in multilayer panels that typically include two substrates, such as a pair of glass substrates, with the interlayer disposed between the two substrates. An example of such a construction is: glass / interlayer / glass, where the interlayer may include any of the interlayers described above. These examples of multilayer panels are not intended to be limiting in any way, as one skilled in the art will readily recognize that numerous constructions other than those described above can be made using the interlayers of the present invention.

[0071]

[0078] The interlayers described herein can be laminated between glass sheets using techniques known in the art. A typical glass lamination process includes the following steps: (1) assembling two substrates (e.g., glass) and an interlayer; (2) briefly heating the assembly via IR radiation or convection; (3) passing the assembly through pressure nip rolls for a first degassing step; (4) heating the assembly a second time to a suitable temperature, such as about 50°C to about 120°C, to create a temporary bond to the assembly sufficient to seal the edges of the interlayer; (5) passing the assembly through a second pressure nip roll to further seal the edges of the interlayer and allow for further manipulation; and (6) autoclaving the assembly for about 30 to 90 minutes at a suitable temperature and pressure, such as between 80°C and 150°C and between 15 psig and 200 psig. Other commercially practiced means known in the art for use in degassing the interlayer-glass interface (steps 2-5) include vacuum bag and vacuum ring processes in which a vacuum is applied to remove air. An alternative lamination process involves the use of a vacuum laminator that first degasses the assembly and then completes the lamination at a sufficiently high temperature and vacuum.

[0072]

[0079] The preferred embodiments of the present invention described above should be used only as examples and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments set forth above can be easily made by those skilled in the art without departing from the spirit of the present invention. The present invention can be further illustrated by the following examples of embodiments thereof, but it will be understood that these examples are included for illustrative purposes only and are not intended to limit the scope of the present invention unless specifically stated otherwise. [Example]

[0073] Example 1

[0080] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / hr through the extruder. A colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 44 kg / hr through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, with the laminated glass samples moved every 0.5 seconds on the sample stage from the dark plateau to cutoff at 3.0 mm / s. The resulting visible transmittance spectra are shown in Figure 2.

[0074]

[0081] D and d were measured on the generated transmittance spectra. Cross sections of the sheets containing the gradient bands were examined with a Leica M165C optical microscope to examine the diffusion of colorant into the encapsulation layer or adjacent layer(s). The discernibility of the Mach bands was subjectively determined based on the appearance of the Mach bands when the laminated glass sample was placed on top of a light box and classified as either "good" (or acceptable) or "poor" (unacceptable). The gradient aesthetics were subjectively graded and classified as "A" (best), "B" (fair), or "C" (worst). The results are summarized in Table 1 below.

[0075] Example 2

[0082] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / h through the extruder. A colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 33 kg / h through the probe. The orifice gap profile in the probe was adjusted to produce the desired transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff on the sample stage at 3.0 mm / s. The resulting visible transmittance spectra are shown in Figure 3. D and d were measured on the transmittance spectra, and Mach band and gradient angles were evaluated as described in Example 1, with the results summarized in Table 1.

[0076] Comparative Example 1

[0083] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / hr through the extruder. A colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 22 kg / hr through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff on the sample stage at 3.0 mm / s. The resulting visible transmittance spectra are shown in Figure 4. D and d were measured on the transmittance spectra, and Mach band and gradient angles were evaluated as described in Example 1, with the results summarized in Table 1.

[0077] Comparative Example 2

[0084] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / hr through the extruder. A colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 33 kg / hr through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff on the sample stage at 3.0 mm / s. The resulting visible transmittance spectra are shown in Figure 5. D and d were measured on the transmittance spectra as described in Example 1, and the results are summarized in Table 1.

[0078] Comparative Example 3

[0085] A clear polyvinyl butyral melt was fed into the three-layer die manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / h through the extruder. A 2% solvent-containing colored polyvinyl butyral was side-fed into a probe inserted into one of the skin layer manifolds at a temperature of 194°C and a flow rate of 22 kg / h through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff on the sample stage at 3.0 mm / s. The resulting visible transmittance spectra are shown in Figure 6. D and d were measured on the transmittance spectra as described in Example 1, and the results are summarized in Table 1.

[0079] Comparative Example 4

[0086] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / h through the extruder. A 2% solvent-containing colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 33 kg / h through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff at 3.0 mm / s on the sample stage. The resulting visible transmittance spectra are shown in Figure 7. D and d were measured on the transmittance spectra as described in Example 1, and the results are summarized in Table 1.

[0080] Comparative Example 5

[0087] A clear polyvinyl butyral melt was fed to the manifold through a feed pipe at a temperature of 204°C and a flow rate of 136 kg / h through the extruder. A 2% solvent-containing colored polyvinyl butyral was side-fed to the probe at a temperature of 194°C and a flow rate of 22 kg / h through the probe. The orifice gap profile in the probe was adjusted to produce the target transmittance spectrum measured in the laminated glass containing the sheet. A 0.76 mm thick sheet was obtained with excellent appearance uniformity across the sheet and an encapsulated gradient band with a width very close to the width of the extrusion orifice in the probe. The sheet was placed between a pair of 2.2 mm thick clear glass sheets and laminated by applying heat and pressure on a Carver press at 2 bar and 150°C for 1 minute, followed by autoclaving the compressed sample at 13 bar and 143°C for 1 hour. After lamination, transmittance spectra were measured on an ILT 1700 Research Radiometer using a Thorlabs OSL1 fiber illuminator as the visible light source, moving the laminated glass samples every 0.5 seconds from the dark plateau to cutoff at 3.0 mm / s on the sample stage. The resulting visible transmittance spectra are shown in Figure 8. D and d were measured on the transmittance spectra as described in Example 1, and the results are summarized in Table 1.

[0081]

[0088] The gradient bands were visually inspected to determine whether the colorant had diffused into adjacent layers, the discernibility of the Mach bands (i.e., whether they were unpleasant), and the gradient aesthetic rating. The gradient bands were also measured to determine D and d, as previously described.

[0082]

[0089] Gradient beauty is a subjective grade given to a test sample by an expert relative to a prefabricated reference specimen. An "A" grade means the sample had a smooth fade-off of the gradient bands without a sharp cut-off. The "C" in a "C" grade means the sample had either a non-smooth gradient fade-off or a sharp cut-off (or possibly both). A "B" grade is a grade between the "A" and "C" grades visually. Mach band discrimination was subjectively characterized as either "good" or "poor." "Good" quality Mach bands are those samples that have weak, broad, and diffuse Mach bands, while samples with sharp, bright (or more pronounced) Mach bands are given a "poor" grade.

[0083]

[0090] Table 1 below shows the results obtained for the Examples and Comparative Examples.

[0084] [Table 1]

[0085]

[0091] The above shows that an interlayer having gradient bands with good visual quality and gradient beauty (as described above) when viewing the Mach bands can be produced when the D and d variables are controlled to certain numbers and D / d is controlled within a predetermined range. Outside the predetermined range, the gradient beauty is poor. Both Examples 1 and 2 have good visual quality (good Mach bands and an "A" gradient beauty rating), D values between 22.9 and 38.1, D / d values less than 2.00, and no diffusion of the colorant or color layer into adjacent layers. All of the comparative examples have at least one characteristic outside the desired range. Both Comparative Examples 1 and 2 have D values within the preferred range, but d is low, and therefore D / d is greater than 2, resulting in a gradient beauty rating of "B." Comparative Example 2 has a low D value, even though D / d is within the desired range, and also results in a gradient beauty rating of "B." Comparative Example 3 also has a low D value, but D / d is within the desired range, but there is colorant diffusion into adjacent layers, resulting in a gradient beauty rating of "C." Comparative Example 4 has a high D value, but D / d is within the desired range, but there is colorant diffusion into adjacent layers, resulting in a gradient beauty rating of "C." Comparative Example 5 has an acceptable D value, but D / d is just 2.00, resulting in colorant diffusion into adjacent layers, resulting in a gradient beauty rating of "C."

[0086] definition

[0092] It should be understood that the following is not intended to be an exhaustive list of defined terms. Other definitions may be given in the description above, for example, with use of the defined term in context.

[0087]

[0093] As used herein, the terms "a," "an," and "the" mean one or more.

[0094] As used herein, the term "and / or," when used in connection with a list of two or more items, means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may contain A only; B only; C only; 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.

[0088]

[0095] As used herein, the terms "comprising," "comprises," and "comprise" are open-ended transitional terms used to transition from a subject listed before the term to one or more elements listed after the term, and the element or elements listed after the transitional term are not necessarily the single element that makes up the subject. As used herein, the terms "having," "has," and "have" have the same open-ended meaning as "including," "include," and "comprise" set forth above. As used herein, the terms "including," "include," and "included" have the same open-ended meaning as "including," "include," and "comprise" set forth above.

[0089]

[0096] As used herein, the term "about" refers to a value within 10 percent of the stated value. This description uses numerical ranges to quantify certain parameters related to the present invention. It should be understood that when numerical ranges are provided, such ranges should be interpreted as providing literal support for claim limitations that only recite the upper limit of the range, as well as for claim limitations that only recite the lower limit of the range. For example, a disclosed numerical range of 10 to 100 provides literal support for claims that recite "greater than 10" (without an upper limit) and claims that recite "less than 100" (without a lower limit). The present invention includes the following embodiments. [1] An intermediate layer having improved gradient quality, comprising: a first layer having a transparent portion and a gradient color band portion, the gradient color band portion being encapsulated within the transparent portion, the gradient color band portion having a cut-off X at the start of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D which is the distance from X to Y, and a distance d which is the distance from Y to Z, the distance D of the gradient portion satisfying the following formula: 22.9 mm < D < 38.1 mm and D / d < 2.00, the intermediate layer. [2] The intermediate layer according to [1], wherein the distance D of the gradient portion satisfies the following formula: 25.4 mm < D < 30.5 mm. [3] The intermediate layer according to [1], wherein D / d < 1.95. [4] The intermediate layer according to [1], wherein D / d < 1.9. [5] The intermediate layer according to [1], wherein D / d > 1.50. [6] The intermediate layer according to [1], wherein D / d ≧ 1.70. [7] The intermediate layer according to [1], wherein D / d < 1.95 and 25.4 mm < D < 30.5 mm. [[ID=第十九]][8] A method for producing an intermediate layer having improved gradient quality, comprising: (a) providing a sheet extrusion die having an orifice and a manifold adapted to supply a polymer melt to the orifice through an extrusion passage; (b) providing a probe located within the manifold and adjacent to the extrusion passage, the probe having an extrusion orifice extending parallel to the probe axis on a surface adjacent to the extrusion passage, the probe being located at a location such that when the main stream of the thermoplastic polymer is supplied to the manifold and extruded through the extrusion passage and through the slit die, the streamlines of the main stream pass by the probe orifice and are substantially parallel and in the extrusion direction; (c) supplying the main stream of the molten thermoplastic polymer to the manifold and supplying a colored secondary stream of the molten thermoplastic polymer to the probe at substantially the same temperature and viscosity; (d) simultaneously extruding both streams such that a layer of the colored polymer having a constant width but a gradually decreasing thickness at one end of the width is completely encapsulated within the main stream of the molten polymer; (e) extruding the integrated stream through the slit die to produce a sheet having an encapsulated gradient color band portion, comprising, The gradient color band portion has a cut-off X at the start of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D which is the distance from X to Y, and a distance d which is the distance from Y to Z, The distance D of the gradient portion satisfies the following formula: 22.9 mm < D < 38.1 mm and D / d < 2.00, a method. [9] The method according to [8], where the distance D of the gradient portion satisfies the following formula: 25.4 mm < D < 30.5 mm.

[10] The method according to [8], where D / d < 1.95.

[11] The method according to [8], where D / d > 1.50.

[12] The method according to [8], where D / d ≥ 1.70.

[13] The method according to [8], where D / d < 1.95 and 25.4 mm < D < 30.5 mm.

[14] An intermediate layer manufactured by the method according to [8].

[15] A first glass substrate, [1] The intermediate layer according to, A second glass substrate, A front glass including.

[16] A first glass substrate,

[14] The intermediate layer according to, A second glass substrate, A front glass including.

[17] A first glass substrate, A second glass substrate, An intermediate layer having improved gradient quality, comprising: A first layer having a transparent portion and a gradient color band portion, the gradient color band portion being encapsulated within the transparent portion, The gradient color band portion has a cut-off X at the start of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D which is the distance from X to Y, and a distance d which is the distance from Y to Z, The distance D of the gradient portion satisfies the following formula: 22.9 mm < D < 38.1 mm and D / d < 2.00, an intermediate layer, Including, The intermediate layer is between the first glass substrate and the second glass substrate, a front glass.

[18] The front glass according to

[17] , where the intermediate layer has a distance D of the gradient portion satisfying the following formula: 25.4 mm < D < 30.5 mm.

[19] The front glass according to

[17] , where the intermediate layer has D / d < 1.95.

[20] The front glass according to

[17] , where the intermediate layer has D / d < 1.95 and 25.4 mm < D < 30.5 mm.

Claims

1. 1. An interlayer having improved gradient quality: a first layer having a transparent portion and a gradient color band portion, the gradient color band portion being encapsulated within the transparent portion; the gradient color band portion has a cutoff X for the beginning of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D that is the distance from X to Y, and a distance d that is the distance from Y to Z; A middle layer, wherein the distance D of the gradient portion satisfies the following formulas: 22.9 mm<D<38.1 mm and D / d<2.

00.

2. 2. The intermediate layer of claim 1, wherein the distance D of the sloped portion satisfies the following formula: 25.4 mm<D<30.5 mm.

3. 2. The intermediate layer of claim 1, wherein D / d<1.

95.

4. 2. The intermediate layer of claim 1, wherein D / d<1.

9.

5. 2. The intermediate layer of claim 1, wherein D / d>1.

50.

6. 1. A method of making an interlayer with improved gradient quality, comprising: (a) providing a sheet extrusion die having a slit die orifice and a manifold adapted to deliver a polymer melt to the slit die orifice through an extrusion passage; (b) providing a probe located within the manifold adjacent the extrusion passage, the probe having an extrusion orifice on a surface adjacent the extrusion passage that extends parallel to the probe axis and extrudes a colored secondary stream of thermoplastic polymer, the probe being located such that when a main stream of thermoplastic polymer is fed into the manifold and extruded through the extrusion passage and through the slit die orifice, the streamlines of the main stream are substantially parallel to and in the direction of extrusion as they pass by the extrusion orifice; (c) delivering a main stream of molten thermoplastic polymer to a manifold and a colored secondary stream of molten thermoplastic polymer at substantially the same temperature and viscosity to a probe; (d) co-extruding both streams so that a layer of pigmented polymer of constant width but tapering in thickness at one end of the width is completely encapsulated within the main stream of molten polymer; (e) extruding the combined main stream and colored secondary stream through a slit die orifice to produce a sheet having encapsulated gradient color band portions; Including, the gradient color band portion has a cutoff X for the beginning of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D that is the distance from X to Y, and a distance d that is the distance from Y to Z; The method wherein the distance D of the sloped portion satisfies the following formulas: 22.9 mm<D<38.1 mm and D / d<2.

00.

7. 7. The method of claim 6, wherein the distance D of the sloped portion satisfies the following formula: 25.4 mm<D<30.5 mm.

8. 7. The method of claim 6, wherein D / d<1.

95.

9. 7. The method of claim 6, wherein D / d>1.

50.

10. 7. The method of claim 6, wherein D / d≧1.

70.

11. a first glass substrate; An intermediate layer according to any one of claims 1 to 5; a second glass substrate; Including the front glass.

12. a first glass substrate; a second glass substrate; 1. An interlayer having improved gradient quality: a first layer having a transparent portion and a gradient color band portion, the gradient color band portion being encapsulated within the transparent portion; the gradient color band portion has a cutoff X for the beginning of the gradient color band, a Y point where the % transmittance of the gradient color band is 40%, a Z point where the % transmittance of the gradient color band is 70%, a distance D that is the distance from X to Y, and a distance d that is the distance from Y to Z; a middle layer, the distance D of the gradient portion of which satisfies the following formulas: 22.9 mm<D<38.1 mm and D / d<2.00; Including, The intermediate layer is a front glass between the first glass substrate and the second glass substrate.

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