Interlayer film for laminated glass, method for manufacturing same, and laminated glass

Abstract

To provide an intermediate film for a laminated glass which can suppress occurrence of optical strain, and is excellent in sound insulating property, and a laminated glass using the intermediate film for the laminated glass.SOLUTION: An intermediate film 1 for a laminated glass includes a first resin layer 10, and a pair of second resin layers 20 arranged on both sides in a thickness direction (Z direction) of the first resin layer 10, wherein a part of the pair of second resin layers 20 is connected to each other in the thickness direction (Z direction), and a cross-sectional shape of an end 11 of the first resin layer 10 adjacent to a connection part where the pair of second resin layers 20 is connected to each other in the thickness direction is not a rectangular shape. A manufacturing method of an intermediate film for a laminated glass manufactures an intermediate film for a laminated glass by co-extrusion. A laminated glass includes a first laminated glass member, a second laminated glass member, and an intermediate film 1 for a laminated glass which is arranged between the first laminated glass member and the second laminated glass member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an interlayer film for laminated glass, a method for producing the same, and laminated glass using the interlayer film for laminated glass. [Background technology]

[0002] Laminated glass is excellent in safety because even if it is broken by an external impact, the amount of glass fragments that scatter is small. For this reason, the laminated glass is widely used in automobiles, railway vehicles, aircraft, ships, buildings, etc. The laminated glass is produced by sandwiching an interlayer film for laminated glass between two glass sheets. An example of the interlayer film for laminated glass is a multilayer interlayer film having a structure of two or more layers.

[0003] As an example of the interlayer film for laminated glass, Patent Document 1 listed below discloses an interlayer film for laminated glass in which an interlayer having horizontally arranged region A made of resin composition A or resin A and region B made of resin composition B or resin B is sandwiched between two covering layers. With this configuration, the interlayer film for laminated glass has excellent sound insulation properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-88785 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in laminated glass using a conventional interlayer film such as that described in Patent Document 1, when embossing press processing is performed to form a textured pattern on the surface, the textured pattern formed is disrupted near the boundary between Region A and Region B, resulting in the problem of optical distortion.

[0006] Another object of the present invention is to provide an interlayer film for laminated glass that can suppress the occurrence of optical distortion and has excellent sound insulation, a method for producing the same, and laminated glass that uses the interlayer film for laminated glass. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that in an interlayer film for laminated glass comprising a first resin layer and a pair of second resin layers arranged on both sides of the first resin layer in the thickness direction, the above-mentioned problems can be solved by adjusting the glass transition temperature and cross-sectional shape of the edge of the first resin layer and the glass transition temperature of the second resin layer, and have completed the present invention as described below. That is, the present invention provides the following [1] to

[14] . [1] An interlayer film for laminated glass comprising a first resin layer and a pair of second resin layers arranged on both sides of the first resin layer in a thickness direction, wherein a portion of the pair of second resin layers is connected to each other in the thickness direction, and at least a portion of an end of the first resin layer adjacent to the connection portion where the pair of second resin layers are connected to each other in the thickness direction has a non-rectangular cross-sectional shape, and the glass transition temperature of the first resin layer is lower than 15°C, and the glass transition temperature of the second resin layer is 15°C or higher. [2] The interlayer film for laminated glass according to [1] above, wherein the first resin layer has a glass transition temperature of less than 15°C, and the second resin layer has a glass transition temperature of 15°C or higher. [3] The interlayer film for laminated glass according to [1] or [2] above, wherein the connection portion where the pair of second resin layers are connected to each other in the thickness direction constitutes at least a part of the edge portion along the outer periphery of the interlayer film for laminated glass. [4] The interlayer film for laminated glass according to the above [3], wherein the length of the end formed by the connecting portion of the pair of second resin layers from the outer periphery of the interlayer film for laminated glass is 20 cm or less. [5] The interlayer film for laminated glass according to any one of [1] to [4] above, which has a portion where the ratio of the thickness of the first resin layer to the thickness of the interlayer film for laminated glass is 40% or less, or a portion where the ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is 40% or less. [6] The interlayer film for laminated glass according to any one of [1] to [5] above, wherein the inclination angle of the edge of the first resin layer is from 0.01 μm / cm to 300 μm / cm. [7] The interlayer film for laminated glass according to any one of [1] to [6] above, wherein the first resin layer has a thickness of 10 μm or more and 2000 μm or less. [8] The interlayer film for laminated glass according to any one of [1] to [7] above, wherein the temperature difference between the glass transition temperature of the second resin layer and the glass transition temperature of the first resin layer is 10°C or more. [9] The interlayer film for laminated glass according to any one of [1] to [8] above, which comprises a plurality of the first resin layers arranged in at least one of the thickness direction and the planar direction, and the second resin layer is interposed between adjacent first resin layers.

[10] The interlayer film for laminated glass according to any one of [1] to [9] above, which has a first end and a second end opposite the first end, and the thickness of the interlayer film for laminated glass at the second end is greater than the thickness of the interlayer film for laminated glass at the first end.

[11] The interlayer film for laminated glass according to

[10] above, wherein the difference in thickness between the second end and the first end of the interlayer film for laminated glass is 50 μm or more.

[12] The interlayer film for laminated glass according to

[10] or

[11] above, wherein the difference in thickness between the interlayer film for laminated glass at the second end and the interlayer film for laminated glass at the first end is 50 μm or more and 2000 μm or less, and the thickness of the first resin layer other than the end is substantially constant, or the cross-sectional shape of the first resin layer is wedge-shaped.

[13] A method for producing an interlayer film for laminated glass, comprising producing the interlayer film for laminated glass according to any one of [1] to

[12] above by coextrusion.

[14] A laminated glass comprising a first laminated glass member, a second laminated glass member, and the interlayer film for laminated glass according to any one of [1] to

[12] above, disposed between the first laminated glass member and the second laminated glass member. [Effects of the Invention]

[0008] The present invention can provide an interlayer film for laminated glass that can suppress the occurrence of optical distortion and has excellent sound insulation, a method for producing the same, and laminated glass that uses the interlayer film for laminated glass. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1(a) is a plan view schematically showing an interlayer film for laminated glass according to one embodiment of the present invention, FIG. 1(b) is a cross-sectional view taken along line AA in FIG. 1(a), and FIG. 1(c) is a cross-sectional view taken along line BB in FIG. 1(a). [Figure 2] FIG. 2 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 11]FIG. 11 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 14] FIG. 14 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 16] FIG. 16 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 17] FIG. 17 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 18] FIG. 18 is a cross-sectional view that schematically shows a modified example of an interlayer film for laminated glass according to one embodiment of the present invention. [Figure 19] FIG. 19 is a cross-sectional view schematically showing a laminated glass according to one embodiment of the present invention. [Figure 20] FIG. 20 is a cross-sectional view schematically showing the interlayer film for laminated glass of Comparative Example 1. As shown in FIG. [Figure 21] FIG. 21 is a cross-sectional view schematically showing the interlayer film for laminated glass of Comparative Example 2. As shown in FIG. [Figure 22] FIG. 22 is a diagram for explaining a method for calculating the inclination angle of the end portion of the first resin layer. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Interlayer film for laminated glass] An interlayer film for laminated glass according to one embodiment of the present invention will be described in detail below with reference to Fig. 1. Fig. 1(a) is a plan view of an interlayer film for laminated glass according to one embodiment of the present invention, Fig. 1(b) is a cross-sectional view taken along line AA in Fig. 1(a), and Fig. 1(c) is a cross-sectional view taken along line BB in Fig. 1(a).

[0011] An interlayer film 1 for laminated glass according to one embodiment of the present invention (hereinafter sometimes referred to as the interlayer film) comprises a first resin layer 10 and a pair of second resin layers 20 disposed on both thickness-wise sides 12, 13 of the first resin layer 10. Portions of the pair of second resin layers 20 are connected to each other in the thickness direction (Z direction), preferably continuously. The cross-sectional shape of an edge 11 of the first resin layer 10 adjacent to the connection portion where the pair of second resin layers 20 are connected to each other in the thickness direction (Z direction) is not rectangular. Furthermore, the glass transition temperature of the first resin layer is less than 15°C, and the glass transition temperature of the second resin layer is 15°C or higher. The connection portion where the pair of second resin layers 20 are connected to each other in the thickness direction (Z direction) constitutes a portion of the edge 3 along the outer periphery 2 of the interlayer film for laminated glass. This allows the interlayer film for laminated glass according to one embodiment of the present invention to suppress optical distortion and exhibit excellent sound insulation. The region where the connection is present is preferably a region where there is no portion with a glass transition temperature of less than 15°C (i.e., no first resin layer). In the interlayer film 1 for laminated glass according to one embodiment of the present invention, the connection portion where a pair of second resin layers 20 are connected to each other in the thickness direction (Z direction) constitutes the entire end portion along one of the two sides parallel to the Y direction, but may also constitute part of the end portion along that side.

[0012] In this specification, the term "layer" refers not only to a layer that extends over the entire surface in the planar direction of the interlayer film for laminated glass 1, but also to a layer that extends over a portion of the surface. The cross sections of the interlayer film for laminated glass shown in the drawings are parallel to the X and Z directions, but are usually substantially the same in the Y direction. Typically, the X direction is the transverse direction (TD) and the Y direction is the machine direction (MD), but this is not particularly limited.

[0013] The principle by which optical distortion is suppressed in one embodiment of the present invention is unclear, but is presumed to be as follows: The interlayer film of the present invention is supported as a whole by the joints of the second resin layer, which has a relatively high glass transition temperature. Therefore, even if the obtained interlayer film is subjected to various surface treatments such as embossing, the support provided by the joints prevents roughness at the interface between the first and second resin layers, and it is presumed that this contributes to suppressing optical distortion.

[0014] Furthermore, the edges of interlayer films for laminated glass are often cut off by trimming or the like. However, when the interlayer film for laminated glass has a structure in which the second resin layer is not present at the edges, as in the present embodiment, the cut-off scrap material consists of the second resin layer alone, making it easier to reuse.

[0015] (Cross-sectional shape of end portion of first resin layer) The cross-sectional shape of the edge 11 of the first resin layer 10 is not rectangular. If the cross-sectional shape of the edge 11 of the first resin layer 10 is rectangular, optical distortion may occur in the interlayer film for laminated glass. This is thought to be because stress concentrates at the edge 11 of the first resin layer 10 when the cross-sectional shape of the edge 11 of the first resin layer 10 is rectangular. The cross-sectional shape of the edge 11 of the first resin layer 10 is, for example, semicircular, like the cross-sectional shape of the edge 11 of the first resin layer 10 in the interlayer film for laminated glass 1 shown in FIG. 1(b). The cross-sectional shape of the edge 11 of the first resin layer 10 is not particularly limited as long as it is not rectangular, and examples thereof include shapes other than semicircular, such as U-shaped, V-shaped, M-shaped, W-shaped, triangular, and trapezoidal shapes, in which the thickness decreases toward the tip. The cross-sectional shape of the end 11 of the first resin layer 10 can be controlled, for example, by adjusting the gap at each coordinate in the width direction (TD) of the slit for supplying the first resin layer provided in the feed block during co-extrusion. In addition, by providing a portion in the width direction of the slit for the first resin layer where resin or resin composition is not supplied, and correspondingly increasing the gap at each coordinate in the width direction (TD) of the slit for the second resin layer, it is possible to form a portion (connection portion) where the second resin layer connects without the first resin layer being present. Furthermore, by merging the second resin at at least one end of a multilayer resin consisting of a first resin layer and a second resin layer formed in a feed block within the feed block, it is possible to form a portion (connection portion) where the second resin layer connects without the first resin layer being present at at least one end. In addition, by merging the second resin at at least one end of a multilayer resin consisting of a first resin layer and a second resin layer formed in a feed block within a mold, a portion (connection portion) where the second resin layer connects without the first resin layer being present at at least one end may be formed. The cross section of the interlayer film for laminated glass 1 shown in FIG. 1(b) is substantially the same cross section in the Y direction shown in FIG. 1(a).

[0016] (Glass transition temperatures of the first resin layer and the second resin layer) The first resin layer 10 has a glass transition temperature of less than 15° C., and the second resin layer 20 has a glass transition temperature of at least 15° C. When the first resin layer 10 has a glass transition temperature of less than 15° C. and the second resin layer 20 has a glass transition temperature of at least 15° C., the sound insulation of the interlayer film 1 for laminated glass can be improved. From this viewpoint, the glass transition temperature of the first resin layer 10 is preferably 14°C or lower, more preferably 10°C or lower, even more preferably 5°C or lower, and even more preferably 0°C or lower. From the same viewpoint, the glass transition temperature of the second resin layer 20 is preferably 16°C or higher, more preferably 20°C or higher, and even more preferably 25°C or higher. The lower limit of the range of the glass transition temperature of the first resin layer 10 is not particularly limited, but is, for example, -20°C, preferably -12°C, and more preferably -7°C. The upper limit of the range of the glass transition temperature of the second resin layer 20 is not particularly limited, but is, for example, 80°C, preferably 60°C, and more preferably 50°C. The glass transition temperatures of the second resin layers provided in the interlayer film for laminated glass may be the same or different. When a plurality of first resin layers are provided as in the modified examples described below, the glass transition temperatures of the first resin layers may be the same or different.

[0017] The glass transition temperature can be determined by peeling each layer from the interlayer film, preparing a measurement sample from each obtained layer, and measuring the viscoelasticity using a viscoelasticity measuring device according to the following method. The measurement sample is stored for 12 hours at room temperature (23±2°C) and humidity (25±5%). Viscoelasticity is then measured using a viscoelasticity measuring device (e.g., the ARES-G2 viscoelasticity measuring device manufactured by TA Instruments). Using parallel plates with a diameter of 8 mm, measurements are performed in shear mode, with the temperature decreasing from 100°C to -20°C at a rate of 3°C / min, at a frequency of 1 Hz, and at a strain of 1%. The peak temperature of the loss tangent in the measurement results is taken as the glass transition temperature (Tg) (°C). The glass transition temperatures of the first resin layer 10 and the second resin layer 20 can be determined depending on the resins used in the first resin layer 10 and the second resin layer 20 and the components used in combination with the resins. For example, when the resin is a polyvinyl acetal resin, the glass transition temperatures can be controlled by adjusting the hydroxyl group content, the degree of acetylation, the degree of acetalization, the average degree of polymerization of the raw material PVA, etc. The glass transition temperatures can also be adjusted by the type and amount of plasticizer added.

[0018] (Temperature Difference Between Glass Transition Temperatures of First Resin Layer and Second Resin Layer) The temperature difference between the glass transition temperature of the second resin layer 20 and the glass transition temperature of the first resin layer 10 is, for example, 5°C or more, and preferably 10°C or more. Increasing the temperature difference between the glass transition temperature of the second resin layer 20 and the glass transition temperature of the first resin layer 10 can further improve the sound insulation of the interlayer film for laminated glass 1. From this perspective, the temperature difference between the glass transition temperature of the second resin layer 20 and the glass transition temperature of the first resin layer 10 is more preferably 12°C or more, even more preferably 20°C or more, and even more preferably 25°C or more. The upper limit of the range of the temperature difference between the glass transition temperature of the second resin layer 20 and the glass transition temperature of the first resin layer 10 is not particularly limited, but is, for example, 50°C, preferably 45°C, more preferably 40°C, and even more preferably 35°C.

[0019] (End length) The length (L1) of the edge 3 formed by the connection between the pair of second resin layers 20, from the outer periphery 2 of the interlayer film for laminated glass 1, is preferably 20 cm or less. A length (L1) of 20 cm or less can further suppress the occurrence of optical distortion in the interlayer film for laminated glass 1. From this perspective, the length (L1) of the edge 3 formed by the second resin layer 20, from the outer periphery 2 of the interlayer film for laminated glass 1 is more preferably 15 cm or less, even more preferably 10 cm or less, and still more preferably 5 cm or less. The lower limit of the length (L1) of the edge 3 formed by the second resin layer 20, from the outer periphery 2 of the interlayer film for laminated glass 1, is not particularly limited, but is, for example, 1 mm, preferably 2 mm, more preferably 5 mm, and even more preferably 10 mm. L1 is usually the length in the X direction.

[0020] (Thickness) The thickness of the first resin layer 10 is preferably 10 μm or more and 2000 μm or less. When the thickness of the first resin layer 10 is 10 μm or more and 2000 μm or less, the sound insulation of the interlayer film for laminated glass 1 can be further improved. From this perspective, the thickness of the first resin layer 10 is more preferably 20 μm or more and 1000 μm or less, even more preferably 40 μm or more and 500 μm or less, even more preferably 50 μm or more and 400 μm or less, particularly preferably 60 μm or more and 300 μm or less, and even more preferably 70 μm or more and 150 μm or less. Here, the thickness of the first resin layer is the 10-point average thickness excluding the end portions. Furthermore, when there are two or more first resin layers, as will be shown in the modified examples described later, it is the total thickness. Furthermore, when the first resin layer is partially multilayered and partially single layered as shown in FIG. 13, the total thickness is measured in the multilayered portions, and the single layer thickness is measured in the single layered portions, and the 10-point average thickness is calculated as described above, thereby determining the thickness of the first resin layer.

[0021] The thickness of the interlayer film 1 for laminated glass is not particularly limited, but is preferably 100 μm or more and 2500 μm or less, more preferably 200 μm or more and 2000 μm or less, even more preferably 300 μm or more and 1500 μm or less, and even more preferably 400 μm or more and 1000 μm or less. Having a thickness of the interlayer film for laminated glass equal to or greater than the above-mentioned lower limit can improve impact resistance and make it easier to ensure adhesion to laminated glass components, etc. On the other hand, having a thickness equal to or less than the above-mentioned upper limit can prevent the thickness of the laminated glass from becoming unnecessarily thick. The thickness of the interlayer film 1 for laminated glass is a 10-point average thickness.

[0022] The thickness of each second resin layer is not particularly limited, but is preferably 45 μm to 1240 μm, more preferably 50 μm to 1110 μm, even more preferably 90 μm to 990 μm, even more preferably 130 μm to 740 μm, particularly preferably 150 μm to 600 μm, and even more preferably 190 μm to 490 μm. The thickness of the second resin layer is the 10-point average thickness of the portions provided on both sides of the first resin layer in the thickness direction. The thicknesses of the second resin layers may be the same or different from each other.

[0023] (thickness ratio) The interlayer film for laminated glass 1 preferably has a portion where the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 is 40% or less. When the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 is 40% or less, the interlayer film can have good penetration resistance, handleability, mechanical strength, and adhesion to laminated glass members. From this perspective, the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 is more preferably 30% or less, even more preferably 20% or less, and even more preferably 15% or less. The ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 is not particularly limited, but is, for example, 2% or more, preferably 5% or more, more preferably 7% or more, and even more preferably 10% or more. Increasing the ratio of the thickness of the first resin layer 10 tends to improve sound insulation performance. Note that the thickness of the first resin layer 10 here refers to the total average thickness as described above, and the thickness of the interlayer film for laminated glass 1 refers to the average thickness as described above. Furthermore, as long as the interlayer film for laminated glass 1 has a portion where the thickness of the first resin layer 10 accounts for 40% or less of the thickness of the interlayer film for laminated glass 1, the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 does not need to be 40% or less across the entire interlayer film for laminated glass 1. However, in a preferred embodiment of the present invention, the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film for laminated glass 1 across the entire interlayer film for laminated glass 1 is 40% or less.

[0024] (tilt angle) The inclination angle of the edge 11 of the first resin layer 10 is preferably 0.01 μm / cm or more and 300 μm / cm or less. When the inclination angle of the edge 11 of the first resin layer 10 is 0.01 μm / cm or more and 300 μm / cm or less, optical distortion in the interlayer film for laminated glass 1 can be further suppressed. From this perspective, the inclination angle of the edge 11 of the first resin layer 10 is more preferably 0.1 μm / cm or more and 100 μm / cm or less, even more preferably 0.2 μm / cm or more and 70 μm / cm or less, still more preferably 0.3 μm / cm or more and 50 μm / cm or less, and particularly preferably 0.4 μm / cm or more and 30 μm / cm or less. The inclination angle of the edge 11 of the first resin layer 10 indicates the rate of increase in thickness per unit distance when the thickness of the edge 11 of the first resin layer 10 increases from the edge of the first resin layer 10 toward the inside. Specifically, the inclination angle of the end portion 11 of the first resin layer 10 can be measured by the method described in the examples below.

[0025] One or both surfaces of the interlayer film 1 for laminated glass may have an uneven shape. The surface of the interlayer film 1 for laminated glass is the surface that comes into contact with the laminated glass component in the laminated glass. The interlayer film 1 for laminated glass preferably has a ten-point average roughness of at least one surface of 5 μm or more. When the surface of the interlayer film 1 for laminated glass has a ten-point average roughness of 5 μm or more, it has excellent degassing properties, making it less likely for air bubbles to form on the surface of the interlayer film 1 for laminated glass when it is pressure-bonded to the laminated glass component. This also prevents blocking when the interlayer film 1 for laminated glass is stacked or wound up, and also prevents optical distortion and the like. The ten-point average roughness is more preferably 10 μm or more, even more preferably 15 μm or more, and even more preferably 20 μm or more. Furthermore, from the viewpoint of improving degassing properties and suppressing optical distortion, the ten-point average roughness is preferably 95 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, and even more preferably 60 μm or less.

[0026] The ten-point average roughness is the ten-point average roughness (Rzjis94) measured in accordance with JIS B 0601-1994. A measuring instrument for measuring the ten-point average roughness (Rzjis94) can be, for example, the "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. More specifically, the ten-point average roughness (Rz) can be measured using a palpator needle with a tip radius of 2 μm and a tip angle of 60° under the following measurement conditions: a cutoff value of 2.5 mm, a reference length of 2.5 mm, a measurement length of 12.5 mm, a preliminary length of 2.5 mm, and a palpator needle feed rate of 0.5 mm / sec, under an environment of 23°C and 30% RH. When the surface of the interlayer film 1 for laminated glass is embossed with ruled lines, the ten-point average roughness (Rz) is measured by moving the palpator needle in a direction perpendicular to the direction of the ruled lines. The ten-point average roughness can be determined by measuring Rzjis94 at 10 equally spaced points from one end to the other and calculating the average value. Although it is preferable that only one surface of the interlayer film 1 for laminated glass has the ten-point average roughness described above, it is preferable that both surfaces have the ten-point average roughness described above.

[0027] (resin) The first resin layer 10 and the second resin layer 20 each contain a resin. The resin used for the first resin layer 10 and the second resin layer 20 may be a curable resin such as a thermosetting resin or a moisture-curable resin, but a thermoplastic resin is preferred. Using a thermoplastic resin makes it easier to produce the interlayer film 1 by co-extrusion, which will be described later.

[0028] Examples of thermoplastic resins used in the first resin layer 10 and the second resin layer 20 include (meth)acrylic resins, polyvinyl acetal resins, polyvinyl alcohol resins (PVA), polyurethane resins (PU), ethylene-vinyl acetate copolymer resins (EVA), saponified ethylene-vinyl acetate copolymers (EVOH), ethylene-methacrylic acid copolymer resins, ionomer resins, isobutylene resins, styrene-isoprene copolymer resins, and styrene-butadiene copolymer resins. Among the above, from the viewpoint of adjusting the glass transition temperature and facilitating the exertion of sound insulation performance, the thermoplastic resin is preferably an ethylene-vinyl acetate copolymer resin, a polyvinyl acetal resin, or a (meth)acrylic resin, more preferably an ethylene-vinyl acetate copolymer resin or a polyvinyl acetal resin, and even more preferably a polyvinyl acetal resin. The use of a polyvinyl acetal resin makes it easier to improve the impact resistance of the laminated glass and to improve the adhesive strength to the laminated glass members.

[0029] The thermoplastic resin may be used singly or in combination in the first resin layer 10 and the second resin layer 20. The thermoplastic resins used in the first resin layer 10 and the second resin layer 20 may be the same or different, but it is preferable to use the same type of resin. Therefore, it is preferable that the resins used in the first resin layer 10 and the second resin layer 20 are both ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, or (meth)acrylic resin, more preferably both are polyvinyl acetal resin or ethylene-vinyl acetate copolymer resin, and even more preferably both are polyvinyl acetal resin.

[0030] (Polyvinyl acetal resin) The polyvinyl acetal resin used in the first resin layer 10 and the second resin layer 20 will be described in detail below. In the following description, the common structure of the polyvinyl acetal resin used in the first resin layer 10 and the second resin layer 20 will be described simply as "polyvinyl acetal resin." The individual structure of the polyvinyl acetal resin used in the first resin layer 10 will be described as "polyvinyl acetal resin (1)," and the individual structure of the polyvinyl acetal resin used in the second resin layer 20 will be described as "polyvinyl acetal resin (2)." Similarly, the thermoplastic resin used in the first resin layer 10 may be referred to as "thermoplastic resin (1)," and the thermoplastic resin used in the second resin layer 20 may be referred to as "thermoplastic resin (2)."

[0031] The polyvinyl acetal resin is not particularly limited as long as it is a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol with an aldehyde. In the following description, the polyvinyl alcohol used to obtain the polyvinyl acetal resin will be referred to as PVA, and the PVAs used to obtain the polyvinyl acetal resins (1) and (2) will be referred to as PVA(1) and (2), respectively. The average degree of polymerization of the PVA is preferably 200 or more, more preferably 500 or more, even more preferably 1000 or more, and even more preferably 1500 or more. When the average degree of polymerization is at least the above lower limit, the penetration resistance of the laminated glass is increased. Furthermore, the average degree of polymerization of the PVA is preferably 5000 or less, more preferably 4000 or less, and even more preferably 3500 or less. When the average degree of polymerization is at most the above upper limit, the interlayer film for laminated glass can be easily formed. Furthermore, it is preferable that the average degree of polymerization of PVA (1) is high, and that of PVA (2) is low. Therefore, it is preferable that the average degree of polymerization of PVA (1) is higher than that of PVA (2), and in this case, the difference between the average degrees of polymerization of PVA (1) and PVA (2) is, for example, 100 to 1800, preferably 200 to 1600, and more preferably 400 to 1500. The average degree of polymerization of PVA (1) is also preferably 2000 or more, more preferably 2100 or more. On the other hand, the average degree of polymerization of PVA (2) is also preferably 2500 or less, more preferably 1900 or less. The average degree of polymerization of polyvinyl alcohol is determined by a method in accordance with JIS K6726 "Testing method for polyvinyl alcohol."

[0032] The aldehyde is not particularly limited, but generally, an aldehyde having 1 to 10 carbon atoms is suitably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and examples thereof include n-butylaldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, benzaldehyde, etc. These aldehydes may be used alone or in combination of two or more. The number of carbon atoms in the acetal group contained in the polyvinyl acetal resin is not particularly limited, but is preferably 1 to 10, more preferably 3 to 5, even more preferably 4 or 5, and particularly preferably 4. Specific examples of the aldehyde include, among those listed above, n-butylaldehyde, n-hexylaldehyde, and n-valeraldehyde, with n-butylaldehyde being more preferred. Therefore, the polyvinyl acetal resin is preferably a polyvinyl butyral resin, and both the polyvinyl acetal resins (1) and (2) are preferably polyvinyl butyral resins.

[0033] Polyvinyl acetal resins generally have acetal groups, hydroxyl groups, and acetyl groups in their side chains. The hydroxyl group content (hydroxyl group amount) of the polyvinyl acetal resin is, for example, from 17 mol% to 38 mol%, and preferably from 20 mol% to 36 mol%. The degree of acetalization of the polyvinyl acetal resin is, for example, 42 mol % or more and 85 mol % or less, and preferably 55 mol % or more and 80 mol % or less. Furthermore, the degree of acetylation (amount of acetyl groups) of the polyvinyl acetal resin is, for example, 0.01 mol % or more and 30 mol % or less, and preferably 0.1 mol % or more and 25 mol % or less.

[0034] More specifically, the hydroxyl group content (hydroxyl group amount) of the polyvinyl acetal resin (1) used in the first resin layer 10 is preferably 17 mol% or more, more preferably 20 mol% or more, and for example, 38 mol% or less, preferably 34 mol% or less. When the hydroxyl group content is equal to or greater than the lower limit, the adhesive strength of the interlayer film for laminated glass is further increased. Furthermore, from the viewpoint of the polyvinyl acetal resin (1) absorbing the plasticizer and improving the sound insulation of the laminated glass, the hydroxyl group content is more preferably 30 mol% or less, and even more preferably 27 mol% or less. Furthermore, when the hydroxyl group content of the polyvinyl acetal resin (1) is 20 mol% or more, high reaction efficiency and excellent productivity are achieved.

[0035] The hydroxyl group content of the polyvinyl acetal resin (polyvinyl acetal resin (2)) used in the second resin layer 20 is, for example, 20 mol% or more, preferably 22 mol% or more, more preferably 24 mol% or more, and even more preferably 26 mol% or more. When the hydroxyl group content is equal to or greater than the lower limit, the bending rigidity can be increased while maintaining sound insulation. Furthermore, the hydroxyl group content of the polyvinyl acetal resin (2) is preferably 38 mol% or less, more preferably 36 mol% or less, and even more preferably 34 mol% or less. When the hydroxyl group content is equal to or less than the upper limit, the polyvinyl acetal resin is more likely to precipitate during synthesis.

[0036] From the viewpoint of further improving sound insulation, the hydroxyl group content of the polyvinyl acetal resin (1) is preferably lower than the hydroxyl group content of the polyvinyl acetal resin (2). When the hydroxyl group content of the polyvinyl acetal resin (1) is lower than the hydroxyl group content of the polyvinyl acetal resin (2), the absolute value of the difference in their contents is, for example, 0.5 mol% or more, preferably 1 mol% or more. This further improves sound insulation. From this perspective, the absolute value of the difference in the hydroxyl group contents is more preferably 1.5 mol% or more, even more preferably 2 mol% or more, even more preferably 3 mol% or more, and particularly preferably 5 mol% or more. Furthermore, the absolute value of the difference in the hydroxyl group contents is preferably 20 mol% or less, more preferably 10 mol% or less.

[0037] The hydroxyl group content of the polyvinyl acetal resin is the molar fraction calculated by dividing the number of ethylene groups having hydroxyl groups by the total number of ethylene groups in the main chain, and is expressed as a percentage. The number of ethylene groups having hydroxyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0038] The degree of acetalization of the polyvinyl acetal resin (1) used in the first resin layer 10 is preferably 47 mol% or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, and preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less. When the degree of acetalization is equal to or greater than the lower limit, the compatibility of the polyvinyl acetal resin (1) with the plasticizer is improved. When the degree of acetalization of the polyvinyl acetal resin (1) is equal to or less than the upper limit, the amount of residual aldehyde in the resin can be reduced. The term "degree of acetalization" refers to the degree of butyralization when the acetal group is a butyral group and the polyvinyl acetal resin (1) is a polyvinyl butyral resin.

[0039] The degree of acetalization of the polyvinyl acetal resin (2) used in the second resin layer 20 (the degree of butyralization in the case of a polyvinyl butyral resin) is, for example, 40 mol% or more, preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 63 mol% or more. It is also preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less. When the degree of acetalization is equal to or greater than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is enhanced. When the degree of acetalization is equal to or less than the upper limit, the amount of residual aldehyde in the resin can be reduced.

[0040] The degree of acetalization is a molar fraction calculated by subtracting the amount of ethylene groups having hydroxyl groups and the amount of ethylene groups having acetyl groups from the total amount of ethylene groups in the main chain, and dividing the result by the total amount of ethylene groups in the main chain. The degree of acetalization (degree of butyralization) may be calculated from the results of measurements performed in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0041] The degree of acetylation (amount of acetyl groups) of the polyvinyl acetal resin (1) used in the first resin layer 10 is preferably 0.01 mol% or more, more preferably 0.1 mol% or more. From the viewpoint of increasing the compatibility between the polyvinyl acetal resin and the plasticizer and facilitating the incorporation of a large amount of plasticizer, the degree of acetylation is more preferably 7 mol% or more, particularly preferably 9 mol% or more. The degree of acetylation of the polyvinyl acetal resin (1) is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 24 mol% or less, and still more preferably 20 mol% or less. When the degree of acetylation is set to the above upper limit or less, the moisture resistance of the interlayer film for laminated glass and the laminated glass is improved.

[0042] The degree of acetylation of the polyvinyl acetal resin (2) used in the second resin layer 20 is preferably 20 mol% or less, more preferably 15 mol% or less, even more preferably 10 mol% or less, and even more preferably 5 mol% or less. When the acetylation degree is equal to or less than the upper limit, the moisture resistance of the interlayer film and laminated glass is improved. Furthermore, the degree of acetylation of the polyvinyl acetal resin (2) is not particularly limited, but is preferably 0.01 mol% or more, and more preferably 0.1 mol% or more. The degree of acetylation is a molar fraction calculated by dividing the amount of ethylene groups having acetyl groups by the total amount of ethylene groups in the main chain, and is expressed as a percentage. The amount of ethylene groups having acetyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0043] The polyvinyl acetal resin is typically an unmodified polyvinyl acetal resin, but may also be a modified polyvinyl acetal resin. The modified polyvinyl acetal resin has a structure (modifying group) other than an acetal group, a hydroxyl group, and an acetyl group, and preferably has a modifying group in a side chain. Examples of the modifying group include those having a polyalkylene oxide structure in the side chain, and those having an alkyl group (e.g., having about 2 to 30 carbon atoms) other than an acetal group or an acetyl group in the side chain.

[0044] (ethylene-vinyl acetate copolymer resin) The ethylene-vinyl acetate copolymer resin used in each resin layer may be a non-crosslinked ethylene-vinyl acetate copolymer resin or a high-temperature crosslinked ethylene-vinyl acetate copolymer resin. Furthermore, modified ethylene-vinyl acetate resins such as saponified ethylene-vinyl acetate copolymers and hydrolyzed ethylene-vinyl acetate resins can also be used as the ethylene-vinyl acetate copolymer resin.

[0045] The ethylene-vinyl acetate copolymer resin preferably has a vinyl acetate content of 10% by mass or more and 50% by mass or less, as measured in accordance with JIS K 6730 "Testing Methods for Ethylene-Vinyl Acetate Resins." By ensuring that the vinyl acetate content is above these lower limits, adhesion to glass plates and the like is improved, and the penetration resistance of the laminated glass is likely to be improved. Furthermore, by ensuring that the vinyl acetate content is below these upper limits, the breaking strength of the interlayer film for laminated glass is increased, and the impact resistance of the laminated glass is improved.

[0046] The glass transition temperature of the resin layer containing the ethylene-vinyl acetate copolymer resin can be adjusted by the vinyl acetate content.

[0047] (plasticizer) When the resin used is a thermoplastic resin, the first resin layer 10 and the second resin layer 20 may further contain a plasticizer. By incorporating a plasticizer into the resin layer, the interlayer film for laminated glass becomes flexible, and as a result, the laminated glass also becomes flexible. Furthermore, when the laminated glass component is inorganic glass, it is possible to improve adhesion to the laminated glass component. When a polyvinyl acetal resin is used as the thermoplastic resin, it is particularly effective to incorporate a plasticizer into the resin layer containing the thermoplastic resin. Therefore, the first resin layer 10 preferably contains a plasticizer in addition to the polyvinyl acetal resin. Furthermore, the second resin layer 20 preferably contains a plasticizer in addition to the polyvinyl acetal resin.

[0048] The plasticizers used in each resin layer will be described in detail below. In the following description, the plasticizers used in each resin layer will be described together, but the plasticizer used in the first resin layer 10 may be referred to as plasticizer (1). The plasticizer used in the second resin layer 20 may be referred to as plasticizer (2). Examples of plasticizers used in the first resin layer 10 and the second resin layer 20 include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and phosphorus-based plasticizers such as organic phosphate-based plasticizers and organic phosphite-based plasticizers. Among these, organic ester plasticizers are preferred. The plasticizer is preferably a liquid plasticizer. A liquid plasticizer is a plasticizer that is liquid at room temperature (23°C) and atmospheric pressure (1 atmosphere).

[0049] Examples of monobasic organic acid esters include esters of glycols and monobasic organic acids. Examples of glycols include polyalkylene glycols in which each alkylene unit has 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, and the number of repeating alkylene units is 2 to 10, preferably 2 to 4. The glycol may also be a monoalkylene glycol having 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, and one repeating unit. Specific examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and butylene glycol. Examples of monobasic organic acids include organic acids having 3 to 10 carbon atoms, and specific examples thereof include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, 2-ethylpentanoic acid, heptanoic acid, n-octylic acid, 2-ethylhexanoic acid, n-nonylic acid, and decylic acid.

[0050] Preferred monobasic organic acid esters include compounds represented by the following formula (1): [ka] In the above formula (1), R1 and R2 each represent an organic group having 2 to 10 carbon atoms, R3 represents an ethylene group, an isopropylene group, or an n-propylene group, and p represents an integer of 3 to 10. In the above formula (1), R1 and R2 each preferably have 5 to 10 carbon atoms, more preferably 6 to 10 carbon atoms. The organic groups of R1 and R2 are preferably hydrocarbon groups, more preferably alkyl groups.

[0051] Specific glycol esters include ethylene glycol di-2-ethyl butyrate, 1,2-propylene glycol di-2-ethyl butyrate, 1,3-propylene glycol di-2-ethyl butyrate, 1,4-butylene glycol di-2-ethyl butyrate, 1,2-butylene glycol di-2-ethyl butyrate, diethylene glycol di-2-ethyl butyrate, diethylene glycol dicaprylate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-2-ethylpentanoate, triethylene glycol di-n-heptanoate, triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpropanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, tetraethylene glycol di-2-ethylbutyrate, and the like.

[0052] Furthermore, examples of polybasic organic acid esters include ester compounds of dibasic organic acids having 4 to 12 carbon atoms, such as adipic acid, sebacic acid, and azelaic acid, with alcohols having 4 to 10 carbon atoms. The alcohols having 4 to 10 carbon atoms may be linear, have a branched structure, or have a cyclic structure. Specific examples include dibutyl sebacate, dioctyl azelaate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, di-(2-butoxyethyl) adipate, dibutyl carbitol adipate, and mixed adipates. Oil-modified alkyd sebacate is also acceptable. Examples of mixed adipates include adipates prepared from two or more alcohols selected from alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms. The organic phosphate plasticizers include phosphate esters such as tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate. The plasticizers may be used alone or in combination of two or more.

[0053] Among the above-mentioned plasticizers, the plasticizer is preferably selected from di-(2-butoxyethyl) adipate (DBEA), triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), and triethylene glycol di-2-ethylpropanoate, more preferably from triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), and triethylene glycol di-2-ethylpropanoate, still more preferably from triethylene glycol di-2-ethylhexanoate and triethylene glycol di-2-ethylbutyrate, with triethylene glycol di-2-ethylhexanoate being particularly preferred.

[0054] In the first resin layer 10 and the second resin layer 20, the content of the plasticizer is not particularly limited, but is, for example, 10 parts by mass or more and 100 parts by mass or less, preferably 15 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0055] More specifically, in the first resin layer 10, the content of the plasticizer (1) (hereinafter sometimes referred to as the content (1)) per 100 parts by mass of the thermoplastic resin (1) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more. When the content (1) is at least the above-mentioned lower limit, the flexibility of the interlayer film for laminated glass is increased, the interlayer film for laminated glass becomes easier to handle, and sound insulation is also likely to be improved. Furthermore, from the viewpoint of sound insulation, it is preferable to increase the content (1), and from such a viewpoint, the content (1) is even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more. The content (1) of the plasticizer (1) is preferably 100 parts by mass or less, more preferably 95 parts by mass or less, even more preferably 90 parts by mass or less, and particularly preferably 85 parts by mass or less. When the content (1) is equal to or less than the above upper limit, the penetration resistance of the laminated glass is further improved.

[0056] The content of the plasticizer in the second resin layer 20 (hereinafter sometimes referred to as "content (2)") per 100 parts by mass of the thermoplastic resin (2) is preferably 10 parts by mass or more. When the content of the plasticizer is equal to or greater than the above-mentioned lower limit, the flexibility of the interlayer film for laminated glass increases, making the interlayer film for laminated glass easier to handle. From these viewpoints, the content of the plasticizer (2) is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and particularly preferably 24 parts by mass or more. The content (2) is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less. When each of these contents is equal to or less than the upper limit, the mechanical properties such as bending rigidity of the interlayer film for laminated glass are improved.

[0057] In order to improve the sound insulation of the laminated glass, it is preferable that the plasticizer content (1) in the first resin layer 10 is the same as or greater than the plasticizer content (2) in the second resin layer 20, and more preferably greater than the content (2). Furthermore, when the content (1) is greater than the content (2), the absolute value of the difference is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more. Increasing the absolute value of the difference in content thus facilitates further improvement of the sound insulation of the laminated glass. Furthermore, the absolute value of the difference is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less.

[0058] The first resin layer 10 and the second resin layer 20 are preferably composed primarily of a thermoplastic resin, or a thermoplastic resin and a plasticizer, and the total amount of the thermoplastic resin and the plasticizer is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less, based on the total amount of each resin layer.

[0059] (coloring agent) The first resin layer 10 and the second resin layer 20 included in the interlayer film 1 for laminated glass may contain a colorant. In the following description, a resin layer containing a colorant may be referred to as a colored layer. The colorant may be uniformly dispersed in the colored layer. The colorant may be contained in at least one of the resin layers included in the interlayer film, and may be contained in the first resin layer 10 or in either of the pair of second resin layers 20, but is preferably contained in at least one of the second resin layers 20.

[0060] The colorant used is not particularly limited, and can be any colorant that has traditionally been incorporated into interlayer films, such as blue, yellow, red, green, purple, white, or black. Pigments, dyes, and the like can be used as the colorant. By using a colorant, the interlayer film for laminated glass can be colored a desired color, thereby enhancing the design of the interlayer film for laminated glass.

[0061] Examples of pigments used in the interlayer film include carbon black, copper phthalocyanine pigments such as pigment blue, phthalocyanine pigments such as cobalt phthalocyanine pigments, anthraquinone pigments, perylene pigments, diketopyrrolopyrrole pigments, quinacridone pigments, perinone pigments, thioindigo pigments, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, threne pigments, dioxazine pigments, pyrrocholine pigments, fluorubine pigments, azo pigments, titanium oxide pigments, calcium carbonate pigments, metal oxide pigments, Ni complex pigments, and other metal complex pigments. Examples of the dye include azo dyes, cyanine dyes, triphenylmethane dyes, phthalocyanine dyes, anthraquinone dyes, naphthoquinone dyes, quinoneimine dyes, methine dyes, azomethine dyes, squarylium dyes, acridine dyes, styryl dyes, coumarin dyes, quinoline dyes, and nitro dyes. The dye may be a disperse dye. The pigments and dyes constituting the colorants described above may be blended directly into the resin, or may be blended into the resin in the form of ink, toner, or the like.

[0062] In addition to the pigments and dyes described above, the coloring agents that can be used as heat-shielding agents in interlayer films can also be used as coloring agents. Heat-shielding agents also block a certain amount of visible light, so the resin layer of the interlayer film can also be colored by including a heat-shielding agent. The heat-shielding agent is typically a material capable of absorbing infrared rays with wavelengths of 780 nm or more, i.e., heat rays. The heat-shielding agent is made of an inorganic material, and typically, heat-shielding particles are used. Specific examples include metal oxide particles and particles other than metal oxide particles, such as lanthanum hexaboride (LaB6) particles. Examples of metal oxide particles include tin oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, and antimony-doped tin oxide particles (ATO particles); zinc oxide particles such as gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminum-doped zinc oxide particles (AZO particles), tin-doped zinc oxide particles, and silicon-doped zinc oxide particles; titanium oxide particles such as niobium-doped titanium oxide particles; indium oxide particles such as tin-doped indium oxide particles (ITO particles); and tungsten oxide particles such as sodium-doped tungsten oxide particles, cesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, and rubidium-doped tungsten oxide particles. Other heat-shielding particles may also be used. The heat-shielding agent may be used alone or in combination of two or more. Among these, metal oxide particles are preferred because of their high heat ray shielding function, and it is more preferable to use at least one selected from ATO particles, GZO particles, ITO particles, and CWO particles, and it is even more preferable to use ITO particles or CWO particles.

[0063] The preferred lower limit of the average particle size of the heat-shielding particles is 10 nm, more preferably 20 nm, and preferably 100 nm, more preferably 80 nm, and even more preferably 50 nm. When the average particle size is equal to or greater than the preferred lower limit, the heat ray shielding property can be sufficiently improved. On the other hand, when the average particle size is equal to or less than the preferred upper limit, the heat-shielding agent is less likely to shield visible light more than necessary. Here, "average particle size" refers to the volume-average particle size. The average particle size can be measured using a particle size distribution analyzer ("UPA-EX150" manufactured by Nikkiso Co., Ltd.) or the like.

[0064] Of the above-mentioned colorants, it is preferable to use pigments and dyes as the colorant, and it is more preferable to use ITO, CWO, and phthalocyanine. By using either a pigment or a dye as the colorant, it becomes easier to color the interlayer film to a desired color with a small amount used.

[0065] The colorant content in the entire interlayer film for laminated glass is, for example, 0.00001% by mass or more and 7% by mass or less, based on the total amount of the interlayer film for laminated glass. By setting the colorant content to 0.00001% by mass or more, it is possible to appropriately color the interlayer film for laminated glass. Furthermore, by setting the content to 7% by mass or less, it is possible to prevent the interlayer film for laminated glass from being colored more than necessary and to prevent the colorant from degrading various functional performances of the interlayer film for laminated glass. The content of the colorant in the entire interlayer film for laminated glass is preferably 0.00001% by mass or more, more preferably 0.00005% by mass or more, even more preferably 0.0001% by mass or more, still more preferably 0.001% by mass or more, still more preferably 0.01% by mass or more, particularly preferably 0.1% by mass or more, and is preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0066] Furthermore, the content of the colorant in the first resin layer 10 and the second resin layer 20 containing the colorant is preferably 0.0001% by mass or more and 7% by mass or less, based on the total amount of each resin layer. By setting the content to 0.0001% by mass or more, the resin layer containing the colorant can appropriately color the interlayer film for laminated glass. Furthermore, by setting the content to 7% by mass or less, it is possible to prevent excessive coloring and to prevent the various functions and performance of each resin layer from being reduced by the colorant. The content of the colorant in each resin layer containing the colorant is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and more preferably 7% by mass or less, and even more preferably 5% by mass or less. When two or more colored layers are provided in the interlayer film for laminated glass, the content of the colorant in each resin layer may be the same as or different from one another.

[0067] Furthermore, when some resin layers in an interlayer film for laminated glass contain a colorant, the other resin layers may be layers that contain substantially no colorant. Note that "substantially no colorant" means that the resin layers may contain colorant that is inevitably mixed in from other components such as colored layers, and the content of the colorant is, for example, less than 0.00005% by mass, preferably less than 0.00001% by mass, and more preferably 0% by mass, based on the total amount of the resin layers.

[0068] (ultraviolet absorber) The first resin layer 10 and the second resin layer 20 constituting the interlayer film for laminated glass may further contain an ultraviolet absorber. By containing an ultraviolet absorber in each resin layer, the interlayer film for laminated glass can be prevented from deteriorating even when used for a long period of time in an environment exposed to light such as sunlight. Examples of usable ultraviolet absorbers include compounds having a malonic acid ester skeleton, compounds having an oxalic acid anilide skeleton, compounds having a benzotriazole skeleton, compounds having a benzophenone skeleton, compounds having a triazine skeleton, compounds having a benzoate skeleton, and compounds having a hindered amine skeleton. Among these, compounds having a benzotriazole skeleton (benzotriazole-based compounds) are preferred. The ultraviolet absorbers may be used alone or in combination of two or more.

[0069] The content of the ultraviolet absorber in the first resin layer 10 and the second resin layer 20 is preferably 0.01% by mass or more and 2% by mass or less, based on the total amount of each resin layer. By setting the content to 0.01% by mass or more, deterioration of each resin layer due to ultraviolet rays contained in sunlight can be appropriately prevented, and durability can be improved. Furthermore, by setting the content to 2% by mass or less, discoloration of the resin layer due to the ultraviolet absorber can be prevented, and effects commensurate with the content can be easily achieved. The content of the ultraviolet absorber is more preferably 0.05% by mass or more and 1.5% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less.

[0070] (antioxidant) The first resin layer 10 and the second resin layer 20 constituting the interlayer film for laminated glass may further contain an antioxidant. When each resin layer of the interlayer film for laminated glass contains an antioxidant, oxidative degradation of the interlayer film for laminated glass is prevented, and the durability of the interlayer film for laminated glass is enhanced. Furthermore, from the viewpoint of enhancing the durability of the interlayer film for laminated glass, one or both of the first resin layer 10 and the second resin layer 20 constituting the interlayer film for laminated glass may contain an antioxidant in addition to an ultraviolet absorber. Examples of antioxidants include phenolic compounds, phosphoric acid compounds, and sulfur compounds. Antioxidants prevent the resin film from oxidative deterioration and improve durability. Among these, phenolic compounds are preferred from the viewpoint of improving durability.

[0071] Examples of the phenolic compounds include 2,6-di-t-butyl-p-cresol (BHT), butylated hydroxyanisole (BHA), 2,6-di-t-butyl-4-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis-(4-methyl-6-butylphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), 4,4'-butylidene-bis-(3-methyl-6-t-butylphenol), 1,1,3-tris-(2-methyl-hydroxy-5-t-butylphenol), tetrakis[methylene-3-(3',5'-butyl-4-hydroxyphenyl)propionate]methane, 1,3,3-tris-(2-methyl-4-hydroxy-5-t-butylphenol)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, bis(3,3'-t-butylphenol) butylic acid glycol ester, and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0072] Examples of the phosphoric acid compounds include trisnonylphenyl phosphite, tridecyl phosphite, 2-ethyl-2-butylpropylene-4,6-tri-tert-butylphenol phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene, tetra(tridecyl)isopropylidenediphenol diphosphite, and tris[2-tert-butyl-4-(3-tert-hydroxy-5-methylphenylthio)-5-methylphenyl]phosphite.

[0073] Examples of the sulfur-based compound include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and β-alkyl mercaptopropionate esters of polyols such as pentaerythritol tetra(β-dodecyl mercaptopropionate). The antioxidants may be used alone or in combination of two or more.

[0074] The content of the antioxidant in the first resin layer and the second resin layer is preferably 0.01% by mass or more and 2% by mass or less, based on the total amount of each resin layer. By setting it to 0.01% by mass or more, oxidative degradation of the interlayer film can be appropriately prevented and durability can be improved. Furthermore, by setting it to 2% by mass or less, effects commensurate with the content can be more easily achieved. The content of the antioxidant is more preferably 0.04% by mass or more and 1.5% by mass or less, and even more preferably 0.06% by mass or more and 1% by mass or less. In some cases, the first resin layer may not contain an antioxidant.

[0075] In addition to the above-mentioned additives, the first resin layer 10 and the second resin layer 20 constituting the interlayer film for laminated glass may also contain known additives used in interlayer films. Specific examples include light stabilizers, adhesion modifiers, fluorescent brightening agents, and crystal nucleating agents. These additives may be used alone or in combination of two or more. The second resin layers provided in the interlayer film for laminated glass may have the same or different compositions. Similarly, when a plurality of first resin layers are provided as in the modified examples described below, the first resin layers may have the same or different compositions.

[0076] (Method of manufacturing interlayer film for laminated glass) The method for producing the interlayer film for laminated glass is not particularly limited, and it may be produced by a conventionally known method, such as extrusion molding or press molding, but production by extrusion molding is preferred. Alternatively, each resin layer may be formed by extrusion molding of a resin that constitutes each resin layer, or a resin composition that contains a resin as well as additives such as a plasticizer and a colorant. When producing the interlayer film for laminated glass by extrusion molding, the Y direction in Figure 1(a) may be defined as the extrusion direction (MD), and the X direction may be defined as the TD. The interlayer film of the present invention is more preferably produced by coextrusion. When an interlayer film for laminated glass is produced by coextrusion molding, it is easy to form the cross-sectional shape of the edge of the first resin layer into a shape other than rectangular.

[0077] In the co-extrusion, a co-extruder equipped with a plurality of extruders and a multi-layer feed block may be used, and the tip of each extruder may be connected to the multi-layer feed block via a molten resin transport pipe or the like. In the co-extruder, the resins or resin compositions for forming each resin layer are supplied from each extruder to a multi-layer feed block via a molten resin transport pipe or the like, where they are joined together and co-extruded from a mold (T-die) as a multi-layer interlayer film.

[0078] In an interlayer film for laminated glass according to one embodiment of the present invention, the edge of the first resin layer may be formed into a predetermined shape, or the first resin layer may be absent in some areas, and the second resin layers on both sides of the first resin layer in the thickness direction may be connected to each other. As described above, the structure of such an interlayer film for laminated glass can be controlled by, for example, adjusting the gap at each coordinate in the width direction (TD) of a slit or the like provided in the feed block during co-extrusion. In addition, by providing a portion in the width direction of the slit for the first resin layer where resin or resin composition is not supplied, and correspondingly increasing the gap at each coordinate in the width direction (TD) of the slit for the second resin layer, a portion (connection portion) where the second resin layer connects without the first resin layer being present can be formed. Furthermore, by merging the second resin at at least one end of a multilayer resin consisting of a first resin layer and a second resin layer formed in a feed block within the feed block, a portion (connection portion) where the second resin layer connects without the first resin layer being present at at least one end may be formed. In addition, by merging the second resin at at least one end of a multilayer resin consisting of a first resin layer and a second resin layer formed in a feed block within a mold, a portion (connection portion) where the second resin layer connects without the first resin layer being present at at least one end may be formed. Furthermore, as will be shown in a modified example below, when manufacturing an interlayer film with a wedge-shaped cross section, the gap at the die outlet may be adjusted along the width direction so as to be asymmetric to match the wedge shape. Furthermore, it is preferable that the interlayer film for laminated glass obtained as described above has an uneven shape formed on one or both surfaces. The method for forming the uneven shape is not particularly limited, and examples thereof include lip embossing, embossing roll, and calender roll.

[0079] (Variation) The interlayer film 1 for laminated glass according to one embodiment of the present invention can be modified as follows.

[0080] <Variation 1> In the interlayer film for laminated glass 1 of one embodiment of the present invention, the connection portion where the pair of second resin layers 20 are connected to each other in the thickness direction (Z direction) constitutes the end portion of the interlayer film for laminated glass. However, in the interlayer film for laminated glass of the present invention, the connection portion where the pair of second resin layers 20 are connected to each other in the thickness direction (Z direction) is not limited to the end portion of the interlayer film for laminated glass. For example, as in the interlayer film for laminated glass 1A shown in FIG. 2, the pair of second resin layers 20 may be connected near the center of the interlayer film for laminated glass 1A. This also suppresses the occurrence of optical distortion in the interlayer film for laminated glass 1A.

[0081] When the first resin layers 10A are connected at a location other than the end portions, the first resin layers 10A are spaced apart from each other in one planar direction (the X direction in FIG. 2) via a connection portion. The length of the connection portion (e.g., L2 in FIG. 2) at a location other than the end portion of the interlayer film for laminated glass (i.e., the separation distance between adjacent first resin layers 10A in the one planar direction) is preferably 1 mm or more, more preferably 2 mm or more, even more preferably 5 mm or more, and even more preferably 10 mm or more, similar to the length L1, and is, for example, 500 mm or less, preferably 300 mm or less. As shown in FIG. 12, which will be described later, when two or more connection portions other than the end portions are provided, the length of each connection portion should be within the above range.

[0082] <Variation 2> In an interlayer film 1 for laminated glass according to one embodiment of the present invention, the cross-sectional shape of the edge 11 of the first resin layer 10 is semicircular. However, in an interlayer film for laminated glass according to the present invention, the cross-sectional shape of the edge of the first resin layer does not have to be rectangular; for example, it may have a shape other than semicircular, with the thickness tapering toward the tip. In this case, the tip of the edge may be curved, as in the case of a semicircular shape, or may be pointed. More specifically, the cross-sectional shape of the edge 11B of the first resin layer 10B may be triangular, as in the interlayer film 1B for laminated glass shown in FIG. 3.

[0083] The cross-sectional shape of the end portion of the first resin layer may be branched into two or more parts. For example, as in the interlayer film 1C for laminated glass shown in FIG. 4, the end portion may have two branched projections extending in an elongated manner from both ends in the thickness direction toward the outside of the interlayer film. In this case, the second resin layer may be inserted between the branched projections. That is, the cross-sectional shape of the end portion 11C of the first resin layer 10C may be U-shaped, with the central portion in the thickness direction recessed toward the inside of the interlayer film. The cross-sectional shape of the end portion of the first resin layer may also have a shape with multiple projections and depressions on the surface.

[0084] <Variation 3> In the interlayer film 1 for laminated glass according to one embodiment of the present invention, the connection portion where the second resin layers 20, 20 are connected constitutes part of the edge 3 provided along the outer periphery of the interlayer film for laminated glass 1. Specifically, it constitutes only one of the two edges. However, in the interlayer film for laminated glass of the present invention, the second resin layer is not limited to constituting only one of the edges along the periphery of the interlayer film for glass, and for example, the connection portion formed by connecting the second resin layers 20, 20 may constitute both one edge and the other edge, as in interlayer films for laminated glass 1D to 1F shown in Figures 5 to 7. Furthermore, the connection portion formed by connecting the second resin layers 20, 20 may constitute the entire edge 3 along the periphery of the interlayer film for laminated glass 1. Furthermore, when the connection portion formed by connecting the second resin layers 20, 20 constitutes both one end and the other end, or when the connection portion constitutes the entire periphery of the end, the cross-sectional shape of the end of the first resin layer at one end and the cross-sectional shape of the end of the first resin layer at the other end may be the same or different. For example, as in the interlayer film 1G for laminated glass shown in Fig. 8, the cross-sectional shape of an end 11G1 of a first resin layer 10G at one end may be U-shaped, and the cross-sectional shape of an end 11G2 of the first resin layer 10G at the other end may be semicircular. In this specification, one end and the other end refer to one end and the other end in any one direction (X direction) along the surface direction of the interlayer film for laminated glass, and preferably to one end or the other end in TD.

[0085] <Variation 4> In an interlayer film 1 for laminated glass according to one embodiment of the present invention, the first resin layer 10 is disposed in the center of the thickness direction (Z direction) of the interlayer film for laminated glass 1. However, in an interlayer film for glass according to the present invention, the position at which the first resin layer is disposed is not limited to the center of the thickness direction of the interlayer film for laminated glass. For example, as in an interlayer film 1H for laminated glass shown in FIG. 9, the position at which the first resin layer 10 is disposed may be shifted toward one surface 5 from the center of the thickness direction of the interlayer film for laminated glass.

[0086] <Variation 5> An interlayer film 1 for laminated glass according to one embodiment of the present invention includes one first resin layer. However, the number of first resin layers included in the interlayer film for laminated glass of the present invention is not limited to one. For example, the interlayer film for laminated glass may include multiple first resin layers aligned in at least one of the thickness direction and the planar direction. In this case, a second resin layer may be interposed between adjacent first resin layers. For example, as shown in FIG. 10 , an interlayer film 1I for laminated glass may include two first resin layers 10I aligned in the thickness direction (Z direction). A second resin layer 20 may be interposed between the two first resin layers 10I. Alternatively, three second resin layers may be connected to each other at the edge 3. Alternatively, the three second resin layers may be connected to each other in a portion other than the edge 3, as shown in FIG. 2 . Of course, three or more first resin layers may be provided and four or more second resin layers may be provided. In this case, the three or more resin layers may be connected to each other at the end portions, or the three or more resin layers may be connected to each other in portions other than the end portions.

[0087] 2 and 11, an interlayer film 1J for laminated glass may include two first resin layers 10J arranged in the planar direction (X direction), and an interlayer film 1K for laminated glass may include four first resin layers 10K arranged in the planar direction (X direction) as shown in Fig. 12. When the first resin layers are arranged in the planar direction, the portions between adjacent first resin layers also form connection portions where the second resin layers are connected to each other in the thickness direction.

[0088] When a plurality of first resin layers are arranged in the thickness direction (Z direction), the thickness of each first resin layer 10 is preferably 10 μm to 100 μm, more preferably 20 μm to 90 μm, and even more preferably 30 μm to 80 μm. The thicknesses of the first resin layers 10 may be the same as or different from each other.

[0089] Furthermore, as shown in Fig. 13, an interlayer film 1L for laminated glass may include two first resin layers 10L aligned in both the thickness direction (Z direction) and the planar direction (X direction). In the interlayer film of Fig. 13, the resin constituting the second resin layer is interposed between the first resin layers 10L, 10L, but in plan view, there is no region where the first resin layer 10L is present between the first resin layers 10L, 10L. Therefore, the portion between the two first resin layers 10L, 10L cannot be considered a connection portion where the second resin layer is connected in the thickness direction.

[0090] <Variation 6> The thickness of the first resin layer 10 in the interlayer film for laminated glass 1 of one embodiment of the present invention is substantially constant except at the edges. However, in the interlayer film for laminated glass of the present invention, the thickness of the first resin layer does not have to be substantially constant. For example, as in the interlayer film for laminated glass 1L shown in FIG. 13, the thickness of the first resin layer 10L may gradually increase and decrease from one end of the interlayer film for laminated glass to the other. Furthermore, as in the interlayer film for laminated glass 1M shown in FIG. 14, the cross-sectional shape of the first resin layer 10M may be a combination of two triangles. Furthermore, as in the interlayer film for laminated glass 1N shown in FIG. 15, the cross-sectional shape of the first resin layer 10N may be a diamond shape. In this specification, the term "substantially constant thickness" is intended to include cases where the thickness varies to a certain extent due to manufacturing errors. Specifically, this means that the ratio of the minimum thickness to the maximum thickness (minimum / maximum) is, for example, about 0.95 or more and 1.00 or less. The ratio of the minimum thickness to the maximum thickness is preferably 0.97 or more and 1.00 or less, more preferably 0.98 or more and 1.00 or less.

[0091] <Variation 7> The thickness of the interlayer film for laminated glass 1 of one embodiment of the present invention is substantially constant. However, the thickness of the interlayer film for laminated glass of the present invention does not have to be substantially constant. For example, the interlayer film for laminated glass of the present invention may have a first edge and a second edge opposite the first edge, and the thickness of the interlayer film for laminated glass at the second edge may be greater than the thickness of the interlayer film for laminated glass at the first edge. For example, as shown in FIG. 16 , the interlayer film for laminated glass 1P may have a first edge 6 and a second edge 7 opposite the first edge 6, and the thickness of the interlayer film for laminated glass 1P at the second edge 7 may be greater than the thickness of the interlayer film for laminated glass 1P at the first edge 6.

[0092] That is, as shown in Fig. 16, the cross section of the interlayer film 1P for laminated glass may be wedge-shaped with a wedge angle α of at least a certain value. The wedge angle α is not particularly limited, but may be, for example, 0.1 mrad or more and 1.2 mrad or less, and preferably 0.15 mrad or more and 1.0 mrad or less. As shown in Fig. 16, the interlayer film 1P for laminated glass may have a thickness that varies from one end to the other, forming a wedge shape throughout, or it may be wedge-shaped only partially from one end to the other, as shown in Fig. 17.

[0093] If the interlayer film for laminated glass has a wedge-shaped cross section, when it is used in a head-up display (HUD), for example, displaying an HUD image in the wedge-shaped cross section makes it easier to reduce the reflective double images that occur when the HUD image is displayed. From this perspective, the difference in thickness between the interlayer film for laminated glass at the second end and the interlayer film for laminated glass at the first end is preferably 30 μm or more, more preferably 50 μm or more and 2000 μm or less, and even more preferably 100 μm or more and 1500 μm or less.

[0094] Furthermore, when there is a difference in thickness between the first end and the second end of the interlayer film as described above, the thickness of the first resin layer other than the end may be substantially constant, or the thickness of the first resin layer may vary to match the wedge shape of the interlayer film. For example, as in the interlayer film 1Q for laminated glass shown in FIG. 17, the thickness of the first resin layer 10Q other than the end 11Q may be constant. Furthermore, as in the interlayer film 1R for laminated glass shown in FIG. 18, the cross-sectional shape of the first resin layer 10R may be wedge-shaped.

[0095] <Variation 8> Furthermore, it goes without saying that the layer structure of the interlayer film for laminated glass is not limited to the above. For example, in the interlayer film for laminated glass shown in each figure, two or more first resin layers may be laminated in the thickness direction to form a multilayer structure. In addition, the second resin layers provided on both sides of the first resin layer in the thickness direction may also be multi-layered as appropriate. When the second resin layer is multi-layered, a portion of the second resin layer does not need to be provided over the entire area from one end to the other end, and may be provided, for example, only in a portion. The second resin layers provided only in a portion do not need to be connected to each other in the area where the first resin layer is not present. In addition, it is also preferable that the second resin layer provided only in a portion thereof contains a colorant to form a colored layer, which makes it easy to color only a portion of the interlayer film for laminated glass.

[0096] <Variation 9> The interlayer film 1 for laminated glass according to one embodiment of the present invention has a portion where the ratio of the thickness of the first resin layer 10 to the thickness of the interlayer film 1 for laminated glass is 40% or less. However, the interlayer film for laminated glass of the present invention may also have a portion where the ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is 40% or less. When the ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is 40% or less, sound insulation performance is likely to be further improved. From this perspective, the ratio of the thickness of the second resin layer 20 to the thickness of the interlayer film for laminated glass is more preferably 30% or less, even more preferably 20% or less, and even more preferably 15% or less. The ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is not particularly limited, but is, for example, 2% or more, preferably 5% or more, more preferably 7% or more, and even more preferably 10% or more. Increasing the thickness ratio of the second resin layer tends to improve the penetration resistance, handleability, mechanical strength, and adhesion to laminated glass members of the interlayer film. The thickness of the second resin layer here refers to the total average thickness, similar to that of the first resin layer described above, and the thickness of the interlayer film for laminated glass refers to the average thickness described above. Also, as long as the interlayer film for laminated glass has a portion where the ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is 40% or less, the ratio of the thickness of the first resin layer to the thickness of the interlayer film for laminated glass does not need to be 40% or less throughout the interlayer film for laminated glass.

[0097] <Modification 10> In the above embodiment, the glass transition temperature of the first resin layer is assumed to be less than 15°C and the glass transition temperature of the second resin layer is assumed to be 15°C or higher. However, as long as the effects of the present invention are achieved, the glass transition temperatures of the first resin layer and the second resin layer do not have to be within the above ranges. Even in this case, however, the first resin layer and the second resin layer may have different compositions by appropriately adjusting the resins and additives used. Furthermore, the first glass transition temperature is preferably adjusted to be lower than the second glass transition temperature, and the preferred range of the temperature difference is as described above.

[0098] [Laminated glass] A laminated glass 100 of one embodiment of the present invention will be described with reference to Fig. 19. The laminated glass 100 of one embodiment of the present invention includes a first laminated glass member 110, a second laminated glass member 120, and an interlayer film for laminated glass 1 disposed between the first laminated glass member 110 and the second laminated glass member 120.

[0099] (First and second laminated glass members) The first and second laminated glass members 110, 120 used in the laminated glass can be glass plates. The glass plates can be either inorganic glass or organic glass, but inorganic glass is preferred. Examples of inorganic glass include, but are not limited to, clear glass, float glass, tempered glass, colored glass, polished glass, patterned glass, wired glass, striped glass, ultraviolet-absorbing glass, infrared-reflecting glass, infrared-absorbing glass, and green glass. Furthermore, the organic glass generally used is what is called resin glass, and examples thereof include various organic glass plates such as polycarbonate plates, (meth)acrylic plates such as polymethyl methacrylate plates, polyester plates such as acrylonitrile-styrene copolymer plates, acrylonitrile-butadiene-styrene copolymer plates, and polyethylene terephthalate plates, fluorine-based resin plates, polyvinyl chloride plates, chlorinated polyvinyl chloride plates, polypropylene plates, polystyrene plates, polysulfone plates, epoxy resin plates, phenolic resin plates, unsaturated polyester resin plates, and polyimide resin plates. The organic resin plates may be subjected to appropriate surface treatments.

[0100] The first and second laminated glass members 110, 120 may be made of the same material or different materials. For example, one may be inorganic glass and the other organic glass, but it is preferable that both the first and second laminated glass members are inorganic glass or organic glass. The thickness of each glass plate used in the first and second laminated glass members 110 and 120 is not particularly limited, but is, for example, about 0.1 to 15 mm, and preferably 0.5 to 5 mm. The thicknesses of the glass plates may be the same or different. Furthermore, when the first and second laminated glass members 110, 120 have different thicknesses, the difference in thickness may be 0.1 mm or more, preferably 0.2 mm. The difference in thickness between the first and second laminated glass members 110, 120 is not particularly limited, but may be, for example, 2 mm or less, preferably 1 mm or less.

[0101] The first and second laminated glass members 110, 120 may be flat glass or curved glass. When one of the first and second laminated glass members is flat glass, the other is preferably flat glass, and when one is curved glass, the other is preferably curved glass. The bending radius of the bent glass in one direction along the planar direction (for example, the X direction) is preferably 4000 mm or more, more preferably 6000 mm or more, and even more preferably 8000 mm or more, and is preferably 25000 mm or less, more preferably 20000 mm or less, and even more preferably 15000 mm or less.

[0102] There are no particular limitations on the method for producing the laminated glass, and the laminated glass may be obtained by sandwiching an interlayer film between two laminated glass members and pressing them together. More specifically, an interlayer film is sandwiched between first and second laminated glass members, and the glass members are passed through a pressure roll or placed in a rubber bag and subjected to vacuum suction to remove any air remaining between the two glass members and the interlayer film. This is followed by pre-bonding at approximately 70 to 110°C to obtain a laminate. The laminate is then placed in an autoclave or pressed at approximately 120 to 150°C and a pressure of 1 to 1.5 MPa to obtain a laminated glass.

[0103] (Variation) The laminated glass 100 of one embodiment of the present invention can be modified as follows. The interlayer film for laminated glass used in the laminated glass 100 of one embodiment of the present invention is not limited to the interlayer film for laminated glass 1 of one embodiment of the present invention, as long as it is an interlayer film for laminated glass of the present invention. For example, the interlayer film for laminated glass of the above-mentioned modified example may be used instead of the interlayer film for laminated glass 1 of one embodiment of the present invention.

[0104] [Applications of interlayer films for laminated glass and laminated glass] The interlayer film for laminated glass and laminated glass according to one embodiment of the present invention can be used in various vehicles such as automobiles, railroad cars, aircraft, ships, and buildings. They can also be used in display device applications, such as surface protection panels for various display devices such as liquid crystal displays and organic EL displays. The interlayer film for laminated glass and laminated glass can also be used for applications other than these. The interlayer film for laminated glass and the laminated glass are preferably interlayer films for laminated glass and laminated glass for vehicles or buildings, and more preferably interlayer films for laminated glass and laminated glass for vehicles. The interlayer film and laminated glass may also be used in head-up displays (HUDs) in vehicle applications. In HUD applications, for example, light from a HUD light source installed inside the vehicle is irradiated onto the laminated glass, and the light reflected by the laminated glass is incident on the eyes of the driver or other person inside the vehicle and is recognized as a HUD image. In HUD applications, it is preferable to use a wedge interlayer film as the interlayer film, as this makes it easier to reduce reflected double images.

[0105] The interlayer film for laminated glass according to one embodiment of the present invention and its modified examples are merely examples of the interlayer film for laminated glass according to the present invention, and therefore the interlayer film for laminated glass according to the present invention is not limited to the interlayer film for laminated glass according to one embodiment of the present invention and its modified examples. Furthermore, the laminated glass according to one embodiment of the present invention and its modified examples are merely examples of the laminated glass of the present invention, and therefore the laminated glass of the present invention is not limited to the laminated glass according to one embodiment of the present invention and its modified examples. [Example]

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0107] The following materials were prepared: (Polyvinyl acetal resin) The polyvinyl acetal resins shown in Table 1 below were used. All of the polyvinyl acetal resins used were acetalized using n-butylaldehyde, which has four carbon atoms. The degree of acetalization (degree of butyralization), degree of acetylation, and hydroxyl group content of the polyvinyl acetal resins were measured according to JIS K6728 "Testing Methods for Polyvinyl Butyral." Note that when measured according to ASTM D1396-92, the values ​​were similar to those measured according to JIS K6728 "Testing Methods for Polyvinyl Butyral." (plasticizer) Triethylene glycol di-2-ethylhexanoate (3GO) (UV screening agent) Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, "Tinuvin 326" manufactured by BASF) (antioxidant) BHT (2,6-di-t-butyl-p-cresol)

[0108] Example 1 <Preparation of composition for forming first resin layer> A resin composition for forming the first resin layer was obtained by mixing 100 parts by mass of a polyvinyl acetal resin of the type shown in Table 1 below, 60 parts by mass of a plasticizer (3GO), 0.2% by mass of an ultraviolet absorber (Tinuvin 326), and 0.2% by mass of an antioxidant (BHT).

[0109] Preparation of the composition for forming the second resin layer: A resin composition for forming the second resin layer was obtained by mixing 100 parts by mass of a polyvinyl acetal resin of the type shown in Table 1 below, 40 parts by mass of a plasticizer (3GO), 0.2% by mass of an ultraviolet blocking agent (Tinuvin 326), and 0.2% by mass of an antioxidant (BHT).

[0110] <Production of interlayer film for laminated glass> In a co-extruder equipped with a multilayer feed block attached to the tip of a first molten resin transport pipe connected to the tip of a first extruder and a second molten resin transport pipe connected to the tip of a second extruder, each resin composition was fed from the first and second extruders through the feed block into a mold (T-die). The resin compositions were co-extruded while adjusting the amount extruded from the T-die to obtain an interlayer film for laminated glass (760 μm thick) having a laminated structure of second resin layer (1) (thickness 330 μm) / first resin layer (1) (thickness 100 μm) / second resin layer (2) (thickness 340 μm). The gap widths at each TD coordinate in the slits for feeding each layer provided in the feed block were adjusted to obtain the cross-sectional structure shown in FIG. 1 .

[0111] (Examples 2 to 21 and Comparative Examples 1 and 2) The types of polyvinyl acetal resins used in the compositions for forming the first resin layer and the second resin layer, as well as the amounts of polyvinyl acetal resin and plasticizer, were set as shown in Tables 1 to 3 below. The gap widths of the slits for supplying each layer provided in the feed block were changed to set the configurations of the interlayer films for laminated glass as shown in Tables 2 and 3. Figures 2 and 3 also show reference figures for the configurations of the interlayer films for laminated glass. Figure 20 is a cross-sectional view showing the configuration of the interlayer film for laminated glass of Comparative Example 1, and Figure 21 is a cross-sectional view showing the configuration of the interlayer film for laminated glass of Comparative Example 2. Other than that, the interlayer films for laminated glass were obtained in the same manner as in Example 1. In Examples 2 to 21 and Comparative Examples 1 and 2, the same types of ultraviolet blocking agent and antioxidant as in Example 1 were blended in the same amounts as in Example 1 (0.2 parts by mass per 100 parts by mass of polyvinyl acetal resin).

[0112] (evaluation) (1) Glass transition temperature The glass transition temperature of each resin layer was measured by the method described in the specification.

[0113] (2) Cross-sectional shape and inclination angle of the end of the first resin layer The obtained interlayer film for laminated glass was cut in the TD direction so that the cross-sectional shape of the edge of the first resin layer could be observed. The cross-section of the edge of the first resin layer was observed using an optical microscope to examine the cross-sectional shape of the edge of the first resin layer. The thickness of the first resin layer was then measured within a 5 cm range in the TD direction from a point where a thickness of 20 μm or more could be confirmed. As shown in Figure 22, the measured thickness of the first resin layer and the distance from the point where the thickness was confirmed to be 20 μm were plotted on a graph. The plotting was performed at 10 mm intervals. The plotted measurement points were approximated by a linear straight line LS using the least squares method. The slope of this straight line LS was defined as the inclination angle. As shown in Figure 4, in the portion where the edge was branched, the thickness of each branched portion was measured at each measurement point, and the average value was defined as the thickness of the resin layer.

[0114] (3) Optical distortion When the laminated glass was produced, the evaluators were asked to check whether the view through the laminated glass was distorted. Observations were conducted by 100 evaluators, and optical distortion was evaluated based on the number of evaluators who judged the scene to be distorted. A (Excellent): Less than 20 people B (Good): 20 to 50 people C (Acceptable): 50 to 70 people D (not possible): 70 people or more

[0115] The evaluation results are shown in Tables 2 and 3 below. In Tables 2 and 3, when the length of the end portion of the second resin layer is expressed as "A / B," this indicates that the length of the end portion of the second resin layer on one end side is A mm, and the length of the end portion of the second resin layer on the other end side is B mm. In Tables 2 and 3, when the inclination angle of the end portion of the first resin layer is expressed as "A / B," this indicates that the inclination angle of the end portion of the first resin layer on one end side is A μm / cm, and the inclination angle of the end portion of the first resin layer on the other end side is B μm / cm. Furthermore, when multiple first resin layers are arranged in the planar direction, the inclination angle of the end portion of the first resin layer on one end side and the inclination angle of the end portion on the other end side of each first resin layer are expressed consecutively.

[0116] [Table 1]

[0117] [Table 2]

[0118] [Table 3]

[0119] The interlayer films for laminated glass of Examples 1 to 21 were able to suppress the occurrence of optical distortion because the cross-sectional shape of the edge of the first resin layer was not rectangular. On the other hand, the interlayer films for laminated glass of Comparative Examples 1 and 2 were unable to suppress the occurrence of optical distortion because the cross-sectional shape of the edge of the first resin layer was rectangular. [Explanation of symbols]

[0120] 1, 1A-1N, 1P-1U...Interlayer film for laminated glass 2...Outer periphery of interlayer film for laminated glass 3...Edge of interlayer film for laminated glass 10, 10A to 10G, 10I to 10N, 10P to 10U...First resin layer 11, 11A to 11G, 11G1, 11G2, 11Q, 11T, 11U...Ends of the first resin layer 20, 20A, 20P to 20R...Second resin layer 100...Laminated glass 110...first laminated glass member 120...Second laminated glass member

Claims

1. An interlayer film for laminated glass comprising a first resin layer and a pair of second resin layers disposed on both sides of the first resin layer in a thickness direction, a portion of the pair of second resin layers being connected to each other in a thickness direction; a cross-sectional shape of at least a part of an end portion of the first resin layer adjacent to a connection portion where the pair of second resin layers are connected to each other in a thickness direction is not rectangular, a connection portion where the pair of second resin layers are connected to each other in the thickness direction constitutes at least a part of an edge portion along an outer periphery of the interlayer film for laminated glass, the length of an end portion formed by the connection portion of the pair of second resin layers from the outer periphery of the interlayer film for laminated glass is 20 cm or less, the inclination angle of the edge of the first resin layer is 0.01 μm / cm or more and 300 μm / cm or less; the interlayer film for laminated glass includes a plurality of the first resin layers arranged in at least one of a thickness direction and a planar direction, an interlayer film for laminated glass, wherein the second resin layer is interposed between adjacent first resin layers.

2. An intermediate film for laminated glass comprising a first resin layer and a pair of second resin layers arranged on both sides of the first resin layer in the thickness direction, a portion of the pair of second resin layers being connected to each other in a thickness direction; a cross-sectional shape of at least a part of an end portion of the first resin layer adjacent to a connection portion where the pair of second resin layers are connected to each other in a thickness direction is not rectangular, a connection portion where the pair of second resin layers are connected to each other in the thickness direction constitutes at least a part of an edge portion along an outer periphery of the interlayer film for laminated glass, the length of an end portion formed by the connection portion of the pair of second resin layers from the outer periphery of the interlayer film for laminated glass is 20 cm or less, the inclination angle of the edge of the first resin layer is 0.01 μm / cm or more and 300 μm / cm or less; the interlayer film for laminated glass has a first end and a second end opposite the first end, the thickness of the interlayer film for laminated glass at the second end is greater than the thickness of the interlayer film for laminated glass at the first end, an interlayer film for laminated glass, wherein the difference in thickness between the second end and the first end is 50 μm or more.

3. The interlayer film for laminated glass according to claim 1, which is used for a head-up display (HUD).

4. the glass transition temperature of the first resin layer is less than 15°C; The interlayer film for laminated glass according to claim 1 , wherein the second resin layer has a glass transition temperature of 15° C. or higher.

5. 2. The interlayer film for laminated glass according to claim 1, wherein the interlayer film for laminated glass has a portion where the ratio of the thickness of the first resin layer to the thickness of the interlayer film for laminated glass is 40% or less, or the interlayer film for laminated glass has a portion where the ratio of the thickness of the second resin layer to the thickness of the interlayer film for laminated glass is 40% or less.

6. 2. The interlayer film for laminated glass according to claim 1, wherein the first resin layer has a thickness of 10 μm or more and 2000 μm or less.

7. 2. The interlayer film for laminated glass according to claim 1, wherein the temperature difference between the glass transition temperature of the second resin layer and the glass transition temperature of the first resin layer is 10°C or more.

8. a first end and a second end opposite the first end; The interlayer film for laminated glass according to claim 1 , wherein the thickness of the interlayer film for laminated glass at the second end is greater than the thickness of the interlayer film for laminated glass at the first end.

9. 9. The interlayer film for laminated glass according to claim 8, wherein a difference in thickness between the second end and the first end of the interlayer film for laminated glass is 50 μm or more.

10. a difference in thickness between the interlayer film for laminated glass at the second end and the interlayer film for laminated glass at the first end is 50 μm or more and 2000 μm or less, 9. The interlayer film for laminated glass according to claim 8, wherein the thickness of the first resin layer other than the end portions is such that the ratio of the minimum thickness to the maximum thickness (minimum thickness / maximum thickness) is 0.95 or more and 1.00 or less, or the cross-sectional shape of the first resin layer is wedge-shaped.

11. An intermediate film for laminated glass as described in claim 2, used for head-up display (HUD) applications.

12. The glass transition temperature of the first resin layer is less than 15°C, The interlayer film for laminated glass according to claim 2 , wherein the second resin layer has a glass transition temperature of 15° C. or higher.

13. An intermediate film for laminated glass as described in claim 2, having a portion where the ratio of the thickness of the first resin layer to the thickness of the intermediate film for laminated glass is 40% or less, or having a portion where the ratio of the thickness of the second resin layer to the thickness of the intermediate film for laminated glass is 40% or less.

14. An intermediate film for laminated glass as described in claim 2, wherein the thickness of the first resin layer is 10 μm or more and 2000 μm or less.

15. An intermediate film for laminated glass as described in claim 2, wherein the temperature difference between the glass transition temperature of the second resin layer and the glass transition temperature of the first resin layer is 10°C or more.

16. The difference in thickness between the thickness of the interlayer film for laminated glass at the second end and the thickness of the interlayer film for laminated glass at the first end is 50 μm or more and 2000 μm or less, 3. The interlayer film for laminated glass according to claim 2, wherein the thickness of the first resin layer other than the end portions is such that the ratio of the minimum thickness to the maximum thickness (minimum thickness / maximum thickness) is 0.95 or more and 1.00 or less, or the cross-sectional shape of the first resin layer is wedge-shaped.

17. A method for producing an interlayer film for laminated glass, comprising producing the interlayer film for laminated glass according to any one of claims 1 to 16 by coextrusion.

18. a first laminated glass member; and a second laminated glass member; and A laminated glass comprising the interlayer film for laminated glass according to any one of claims 1 to 16, disposed between the first laminated glass member and the second laminated glass member.

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