INTERMEDIATE FILM FOR LAMINATED GLASS AND LAMINATED GLASS

Abstract

An interlayer film for laminated glass is provided with which distortion in the appearance of the laminated glass can be significantly suppressed. The interlayer film for laminated glass according to the present invention has a first end, and the other end is on the opposite side of the first end. The other end has a thickness that is greater than the thickness of the first end. The interlayer film as a whole has a wedge angle of 0.1 mrad or more, and the next absolute value A in all sections A located every 150 mm in the next measurement of partial wedge angles is 0.4 mrad or less.

Description

Interlayer film for laminated glass and laminated glass

[0001] The present invention relates to an interlayer film for laminated glass used to obtain laminated glass. The present invention also relates to laminated glass using the above interlayer film for laminated glass.

[0002] Laminated glass generally has a small amount of scattered glass fragments even when damaged by an external impact and is excellent in safety. Therefore, the above laminated glass is widely used in automobiles, railway vehicles, airplanes, ships, buildings, and the like. The above laminated glass is manufactured by sandwiching an interlayer film for laminated glass between a pair of glass plates.

[0003] In addition, a head-up display (HUD) is known as the above laminated glass used in automobiles. In the HUD, measurement information such as speed, which is the driving data of the automobile, can be displayed on the front glass of the automobile, and the driver can recognize it as if the display is projected in front of the front glass.

[0004] In the above HUD, there is a problem that measurement information and the like look double.

[0005] In order to suppress double images, a wedge-shaped interlayer film is used. Patent Document 1 below discloses laminated glass in which a wedge-shaped interlayer film having a predetermined wedge angle is sandwiched between a pair of glass plates. In such laminated glass, by adjusting the wedge angle of the interlayer film, the display of measurement information reflected by one glass plate and the display of measurement information reflected by another glass plate can be made to meet at one point in the driver's field of vision. Therefore, it is difficult for the display of measurement information to look double, and it is difficult to obstruct the driver's field of vision.

[0006] Japanese Patent Publication No. Hei 4-502525

[0007] Conventionally, in order to suppress double images, the wedge angle of the interlayer film has been adjusted. However, simply adjusting the wedge angle of the interlayer film may partially cause distortion in the appearance of the laminated glass.

[0008] In recent years, the diversification of HUDs has created a demand for interlayers with non-uniform wedge angles. For example, if the wedge angle of the display area of ​​the interlayer corresponding to the HUD display area is large, the wedge angle of the areas outside the display area may be reduced. By adjusting the wedge angle in this way, it is possible to prevent the overall wedge angle of the interlayer from becoming too large. By preventing the overall wedge angle of the interlayer from becoming too large, it is possible to suppress the occurrence of wrinkles in the interlayer. In addition, when the interlayer is made into a roll, winding misalignment becomes less likely.

[0009] However, in interlayers where the wedge angle is not constant, there are likely to be locations where the wedge angle changes significantly. Therefore, the appearance of laminated glass tends to be partially distorted in these areas. In particular, distortion can occur in the appearance of laminated glass at locations where the wedge angle changes significantly.

[0010] The object of the present invention is to provide an interlayer for laminated glass that can significantly suppress distortion in the appearance of laminated glass. Another object of the present invention is to provide laminated glass using the above-mentioned interlayer for laminated glass.

[0011] In a broader sense, the present invention provides an interlayer for laminated glass (in this specification, "interlayer for laminated glass" may be abbreviated as "interlayer") having one end and the other end on the opposite side of the one end, wherein the thickness of the other end is greater than the thickness of the one end, the wedge angle of the entire interlayer is 0.1 mrad or more, and in the measurement of the partial wedge angle described below, the absolute value A in all sections A at 150 mm intervals is 0.4 mrad or less.

[0012] Measurement of partial wedge angle: Measure the partial wedge angle in the following order from 1 to 4.

[0013] 1. Starting from a point 20 cm from one end of the interlayer to the other end, and ending at a point 20 cm from the other end of the interlayer to the first end, select point A at intervals of 2 mm.

[0014] 2. Calculate the partial wedge angle A in each 40 mm sub-region A in the direction connecting one end and the other end, centered on each point A.

[0015] 3. Sections A are set at 150 mm intervals from the starting point to the ending point.

[0016] 4. In each section A, select the maximum and minimum values ​​of all partial wedge angles A in the subregion A where point A exists within section A, and find the absolute value A of the difference between the maximum and minimum values.

[0017] In a particular aspect of the interlayer according to the present invention, the interlayer is an interlayer for laminated glass used in a laminated glass that is a head-up display, and has a display-compatible area corresponding to the display area of ​​the head-up display.

[0018] In a particular aspect of the interlayer according to the present invention, the interlayer includes a thermoplastic resin.

[0019] In a particular aspect of the interfilm according to the present invention, the interfilm contains a plasticizer.

[0020] In a particular aspect of the interlayer according to the present invention, the interlayer comprises a first layer and a second layer disposed on the first surface side of the first layer.

[0021] In a particular aspect of the interfilm according to the present invention, the first layer comprises a polyvinyl acetal resin, and the second layer comprises a polyvinyl acetal resin, wherein the hydroxyl group content of the polyvinyl acetal resin in the first layer is lower than the hydroxyl group content of the polyvinyl acetal resin in the second layer.

[0022] In a particular aspect of the interfilm according to the present invention, the first layer comprises a polyvinyl acetal resin, the second layer comprises a polyvinyl acetal resin, the first layer comprises a plasticizer, the second layer comprises a plasticizer, and the content of the plasticizer in the first layer relative to 100 parts by weight of the polyvinyl acetal resin in the first layer is greater than the content of the plasticizer in the second layer relative to 100 parts by weight of the polyvinyl acetal resin in the second layer.

[0023] In a particular aspect of the interlayer according to the present invention, the interlayer has a portion in which the cross-sectional shape in the thickness direction is wedge-shaped, within a region from 18 cm from one end toward the other end to 61.8 cm from the one end toward the other end.

[0024] According to a broad aspect of the present invention, a laminated glass is provided comprising a first laminated glass member, a second laminated glass member, and the above-described interlayer for laminated glass, wherein the interlayer for laminated glass is disposed between the first laminated glass member and the second laminated glass member.

[0025] The interlayer for laminated glass according to the present invention has one end and the other end on the opposite side of the first end, with the thickness of the other end being greater than the thickness of the first end. The wedge angle of the entire interlayer for laminated glass according to the present invention is 0.1 mrad or more. In the interlayer for laminated glass according to the present invention, in the measurement of the partial wedge angle, the absolute value A in all sections A at 150 mm intervals is 0.4 mrad or less. Because the interlayer for laminated glass according to the present invention is provided with the above configuration, distortion in the appearance of the laminated glass can be considerably suppressed.

[0026] Figures 1(a) and 1(b) are schematic cross-sectional and front views showing an interlayer for laminated glass according to the first embodiment of the present invention. Figures 2(a) and 2(b) are schematic cross-sectional and front views showing an interlayer for laminated glass according to the second embodiment of the present invention. Figure 3 is a schematic cross-sectional view showing an interlayer for laminated glass according to the third embodiment of the present invention. Figure 4 is a schematic cross-sectional view showing an interlayer for laminated glass according to the fourth embodiment of the present invention. Figure 5 is a schematic cross-sectional view showing an interlayer for laminated glass according to the fifth embodiment of the present invention. Figure 6 is a schematic cross-sectional view showing an interlayer for laminated glass according to the sixth embodiment of the present invention. Figure 7 is a cross-sectional view showing an example of laminated glass using the interlayer for laminated glass shown in Figure 1. Figure 8 is a schematic perspective view showing a roll body on which the interlayer for laminated glass shown in Figure 1 is wound.

[0027] The details of the present invention will be described below.

[0028] The interlayer for laminated glass according to the present invention (which may be abbreviated as "interlayer" in this specification) is used in laminated glass.

[0029] The interlayer according to the present invention has a single-layer structure or a structure of two or more layers. The interlayer according to the present invention may have a single-layer structure or a structure of two or more layers. The interlayer according to the present invention may have a two-layer structure, a three-layer structure or a structure of three or more layers. The interlayer according to the present invention may be a single-layer interlayer or a multi-layer interlayer.

[0030] The interlayer according to the present invention has one end and another end on the opposite side of the first end. The first end and the other end are the opposing ends on both sides of the interlayer. In the interlayer according to the present invention, the thickness of the other end is greater than the thickness of the first end.

[0031] The interlayer according to the present invention has, for example, a display-compatible region corresponding to the display area of ​​a head-up display. The display-compatible region is a region in which information can be displayed clearly.

[0032] Furthermore, the wedge angle of the entire interlayer according to the present invention is 0.1 mrad or greater.

[0033] In the interlayer according to the present invention, the following partial wedge angles are measured.

[0034] Measurement of partial wedge angle: Measure the partial wedge angle in the following order from 1 to 4.

[0035] 1. Starting from a point 20 cm from one end of the interlayer to the other end, and ending at a point 20 cm from the other end to the first end, select point A at intervals of 2 mm.

[0036] 2. Calculate the partial wedge angle A in each 40 mm sub-region A in the direction connecting one end and the other end, centered on each point A.

[0037] 3. Section A is set at 150 mm intervals from the above starting point to the above ending point.

[0038] 4: In each of the sections A, select the maximum value and the minimum value among all of the partial wedge angles A in the partial region A within the section A where the point A exists, and obtain the absolute value A of the difference between the maximum value and the minimum value.

[0039] In 1 above, select points up to a position where points at 2 mm intervals can be selected from one end side toward the other end side (a position where the interval does not become less than 2 mm).

[0040] In 2 above, the partial region A closest to the one end side of the intermediate film is the partial region A1 from 18 cm to 22 cm from the one end, and the next partial region A is the partial region A2 from 18.2 cm to 22.2 cm from the one end. Two adjacent partial regions A overlap each other by 38 mm in the direction connecting the one end and the other end. Each partial region A is a partial region from (18 + 0.2 × n) cm to (22 + 0.2 × n) cm from the one end (n is an integer).

[0041] In 2 above, let the partial wedge angle calculated in each partial region A be the partial wedge angle (θA).

[0042] In 3 above, set the section A up to a position where a 150 mm section can be set from one end side toward the other end side (a position where the section does not become less than 150 mm).

[0043] In 3 above, the first section A is the section A1 from 0 to 150 mm from the start point to the end point, and the next section A is the section A2 from 150 to 300 mm from the start point to the end point. The first section A is the section A1 from 20 to 35 cm from the one end, and the next section A is the section A2 from 35 to 50 cm from the one end.

[0044] In 4 above, obtain the maximum value and the minimum value of the partial wedge angle A in each section A. Each section A (each of the sections A1, A2,...) has 76 values of the partial wedge angle A. Select the maximum value and the minimum value from these 76 values of the partial wedge angle A, and obtain the absolute value A of the difference between the maximum value and the minimum value.

[0045] In the present invention, in the measurement of the above partial wedge angle, in all intervals A (all of intervals A1, A2, ...), the absolute value A is 0.4 mrad or less. In the present invention, the maximum value of the absolute value A is 0.4 mrad or less.

[0046] In the interlayer film for laminated glass according to the present invention, since the above configuration is provided, the distortion in the appearance of the laminated glass can be considerably suppressed.

[0047] Specifically, the distortion in the appearance of the laminated glass is a phenomenon in which the scenery seen through the laminated glass is distorted. The distortion can be evaluated by tilting the laminated glass at 45°, irradiating light from a strong light source 3 m away onto the laminated glass tilted at 45°, and projecting a transmitted image onto a screen approximately 2 m away.

[0048] From the viewpoint of further suppressing the distortion in the appearance of the laminated glass, in the measurement of the above partial wedge angle, the absolute value A is preferably 0.35 mrad or less, more preferably 0.3 mrad or less. From the viewpoint of further suppressing the distortion in the appearance of the laminated glass, the maximum value of the absolute value A is preferably 0.35 mrad or less, more preferably 0.3 mrad or less.

[0049] Further, since the interlayer film according to the present invention has the above configuration, double images in the laminated glass can also be considerably suppressed. In the present invention, when display information is reflected from the display unit to the laminated glass, the generation of double images is considerably suppressed.

[0050] One of the above partial wedge angles (θA) is an interior angle at the intersection of a straight line connecting the surface portion (first surface portion) on one side of the above partial region A between the end on one side and the end on the other side in one of the above partial regions A and a straight line connecting the surface portion (second surface portion) on the other side of the interlayer film between the end on one side and the end on the other side in one of the above partial regions A.

[0051] From the viewpoint of more effectively suppressing double images, it is preferable that the thickness increases from one end to the other end in a region of 80% or more (more preferably 85% or more, even more preferably 90% or more, and especially preferably 95% or more) within the region from 18 cm from one end to the other end to 61.8 cm from one end to the other end.

[0052] The interlayer according to the present invention is suitably used in laminated glass for head-up displays (HUDs). Preferably, the interlayer according to the present invention is an interlayer for HUDs.

[0053] The interlayer according to the present invention preferably has a display-compatible area corresponding to the display area of ​​the HUD. From the viewpoint of more effectively suppressing double images, it is preferable that the interlayer according to the present invention has the display-compatible area within a region from 18 cm from one end toward the other end to 61.8 cm from the one end toward the other end.

[0054] From the viewpoint of effectively suppressing double images, it is preferable that the interlayer has a portion with a wedge-shaped cross-sectional shape in the thickness direction within the region from 18 cm from one end to the other end to 61.8 cm from one end to the other end. The portion with a wedge-shaped cross-sectional shape in the thickness direction only needs to be present in at least a part of the above region.

[0055] The interlayer according to the present invention may have a shade region. The shade region may be separate from the display-compatible region. The shade region is provided, for example, to prevent the driver from experiencing glare from sunlight or outdoor lighting while driving. The shade region may also be provided to provide heat shielding properties. The shade region is preferably located at the edge of the interlayer. The shade region is preferably in the shape of a strip.

[0056] In shaded areas, colorants or fillers may be used to alter the color and visible light transmittance. The colorants or fillers may be present in only a portion of the interlayer thickness or throughout the entire interlayer thickness.

[0057] From the viewpoint of further improving the display and further widening the field of view, the visible light transmittance of the display area is preferably 80% or more, more preferably 88% or more, and even more preferably 90% or more. The visible light transmittance of the display area is preferably higher than the visible light transmittance of the shade area. The visible light transmittance of the display area may be lower than the visible light transmittance of the shade area. The visible light transmittance of the display area is preferably 50% or more higher, and more preferably 60% or more higher than the visible light transmittance of the shade area.

[0058] Furthermore, if, for example, the visible light transmittance changes in the interlayer between the display area and the shaded area, the visible light transmittance is measured at the center of the display area and the center of the shaded area.

[0059] Using a spectrophotometer (Hitachi High-Tech Corporation's "U-4100"), the visible light transmittance of the resulting laminated glass at wavelengths of 380 to 780 nm can be measured in accordance with JIS R3211:1998. It is preferable to use 2 mm thick clear glass as the glass plate.

[0060] The above-mentioned display area preferably has both a length direction and a width direction. Since the interlayer film offers excellent versatility, it is preferable that the width direction of the above-mentioned display area is in the direction connecting one end and the other end. The above-mentioned display area is preferably in the shape of a strip.

[0061] The interlayer film described above preferably has an MD direction and a TD direction. The interlayer film is obtained, for example, by melt extrusion molding. The MD direction is the flow direction of the interlayer film during its manufacture. The TD direction is perpendicular to the flow direction of the interlayer film during its manufacture and is also perpendicular to the thickness direction of the interlayer film. It is preferable that the one end and the other end are located on both sides of the TD direction.

[0062] From the viewpoint of further improving the display, it is preferable that the interlayer has a portion with a wedge-shaped cross-sectional shape in the thickness direction. It is preferable that the cross-sectional shape in the thickness direction of the display-compatible area is wedge-shaped.

[0063] Specific embodiments of the present invention will be described below with reference to the drawings.

[0064] Figures 1(a) and 1(b) are schematic cross-sectional and front views, respectively, of an interlayer for laminated glass according to a first embodiment of the present invention. Figure 1(a) is a cross-sectional view taken along the line I-I in Figure 1(b). Note that the size and dimensions of the interlayer in Figure 1 and the figures described later have been appropriately altered from the actual size and shape for illustrative purposes.

[0065] Figure 1(a) shows a cross-section of the interlayer 11 in the thickness direction. Note that in Figure 1(a) and the figures described later, for illustrative purposes, the thickness of the interlayer and each layer constituting the interlayer, as well as the wedge angle (θ), are shown differently from the actual thickness and wedge angle.

[0066] The interlayer 11 comprises a first layer 1 (intermediate layer), a second layer 2 (surface layer), and a third layer 3 (surface layer). The second layer 2 is positioned on the first surface side of the first layer 1 and laminated. The third layer 3 is positioned on the second surface side of the first layer 1, opposite to the first surface, and laminated. The first layer 1 is positioned between the second layer 2 and the third layer 3 and sandwiched between them. The interlayer 11 is used to obtain laminated glass. The interlayer 11 is an interlayer for laminated glass. The interlayer 11 is a multilayer interlayer.

[0067] The interlayer 11 has one end 11a and the other end 11b on the opposite side of the first end 11a. The first end 11a and the other end 11b are opposing ends on both sides. The cross-sectional shape in the thickness direction of the second layer 2 and the third layer 3 is wedge-shaped. The cross-sectional shape in the thickness direction of the first layer 1 is rectangular. The thickness of the second layer 2 and the third layer 3 is greater on the other end 11b side than on the first end 11a side. Therefore, the thickness of the other end 11b of the interlayer 11 is greater than the thickness of the first end 11a. Consequently, the interlayer 11 has a thin region and a thick region.

[0068] The interlayer 11 has a region where its thickness increases from one end 11a to the other end 11b. Within the region where the thickness of the interlayer 11 increases, the amount of thickness increase is uniform from one end 11a to the other end 11b.

[0069] The interlayer 11 has a display-compatible region R1 that corresponds to the display area of ​​the head-up display. The interlayer 11 has a peripheral region R2 adjacent to the display-compatible region R1. In this embodiment, the display-compatible region R1 is the region from a position 18 cm from one end 11a toward the other end 11b to a position 63.8 cm from one end 11a toward the other end 11b.

[0070] The interlayer 11 has a shade region R3, separated from the display-compatible region R1. The shade region R3 is located at the edge of the interlayer 11.

[0071] The interlayer may have the shape shown in Figure 1(a), and may be a single layer, two layers, or four or more layers.

[0072] Figure 8 is a schematic perspective view showing a roll body on which the interlayer film for laminated glass shown in Figure 1 is wound.

[0073] The interlayer film 11 may be wound up to form a roll body 51 of the interlayer film 11.

[0074] The roll body 51 shown in Figure 8 comprises a winding core 61 and an interlayer film 11. The interlayer film 11 is wound around the outer circumference of the winding core 61.

[0075] Figures 2(a) and 2(b) are schematic cross-sectional and front views, respectively, of an interlayer for laminated glass according to a second embodiment of the present invention. Figure 2(a) is a cross-sectional view along the line I-I in Figure 2(b). Figure 2(a) shows a cross-section of the interlayer 11A in the thickness direction.

[0076] The interlayer 11A shown in Figure 2 comprises a first layer 1A. The interlayer 11A has a single-layer structure consisting only of the first layer 1A, and is a single-layer interlayer. The interlayer 11A is the first layer 1A. The interlayer 11A is used to obtain laminated glass. The interlayer 11A is an interlayer for laminated glass.

[0077] The interlayer 11A has one end 11a and the other end 11b on the opposite side of the one end 11a. The one end 11a and the other end 11b are opposing ends on both sides. The thickness of the other end 11b of the interlayer 11A is greater than the thickness of the one end 11a. Therefore, the interlayer 11A and the first layer 1A have a region with a thin thickness and a region with a thick thickness.

[0078] The interlayer 11A has a region in which its thickness increases from one end 11a to the other end 11b. Within the region in which the thickness increases, the amount of thickness increase is uniform from one end 11a to the other end 11b.

[0079] The interlayer 11A and the first layer 1A have portions 11Aa, 1Aa with a rectangular cross-sectional shape in the thickness direction and portions 11Ab, 1Ab with a wedge-shaped cross-sectional shape in the thickness direction.

[0080] The interlayer 11A has a display-compatible region R1 that corresponds to the display area of ​​the head-up display. The interlayer 11A has a peripheral region R2 adjacent to the display-compatible region R1.

[0081] The interlayer 11A has a shade region R3, separated from the display-compatible region R1. The shade region R3 is located at the edge of the interlayer 11A.

[0082] The interlayer may have the shape shown in Figure 2(a) and may consist of two or more layers.

[0083] Figure 3 is a schematic cross-sectional view showing an interlayer for laminated glass according to a third embodiment of the present invention. In Figure 3, a cross-section in the thickness direction of the interlayer 11B is shown.

[0084] The interlayer 11B shown in Figure 3 comprises a first layer 1B (interlayer), a second layer 2B (surface layer), and a third layer 3B (surface layer). The amount of thickness increase in the region where the thickness increases differs between the interlayer 11 and the interlayer 11B.

[0085] The interlayer 11B has a region where its thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the interlayer 11B has a portion where the amount of thickness increase becomes larger from one end 11a to the other end 11b. Furthermore, the interlayer 11B has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the interlayer 11B has a portion where the wedge angle becomes larger from one end to the other end.

[0086] Figure 4 is a schematic cross-sectional view showing an interlayer for laminated glass according to a fourth embodiment of the present invention. In Figure 4, a cross-section in the thickness direction of the interlayer 11C is shown.

[0087] The interlayer 11C shown in Figure 4 comprises a first layer 1C. The interlayer 11C has a single-layer structure consisting only of the first layer 1C, and is a single-layer interlayer. The amount of thickness increase in the region where the thickness increases differs between the interlayer 11A and the interlayer 11C.

[0088] The interlayer 11C has a region where its thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the interlayer 11C has a portion where the amount of thickness increase becomes larger from one end 11a to the other end 11b. Furthermore, the interlayer 11C has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the interlayer 11C has a portion where the wedge angle becomes larger from one end to the other end.

[0089] The interlayer 11C and the first layer 1C have portions 11Ca, 1Ca with a rectangular cross-sectional shape in the thickness direction and portions 11Cb, 1Cb with a wedge-shaped cross-sectional shape in the thickness direction.

[0090] Figure 5 is a schematic cross-sectional view showing an interlayer for laminated glass according to a fifth embodiment of the present invention. In Figure 5, a cross-section of the interlayer 11D in the thickness direction is shown.

[0091] The interlayer 11D shown in Figure 5 comprises a first layer 1D (interlayer), a second layer 2D (surface layer), and a third layer 3D (surface layer). The amount of thickness increase in the region where the thickness increases differs between the interlayer 11 and the interlayer 11D.

[0092] The interlayer 11D has a region where its thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the interlayer 11D has a portion where the increase in thickness decreases from one end 11a to the other end 11b. Furthermore, the interlayer 11D has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the interlayer 11D has a portion where the wedge angle decreases from one end to the other end.

[0093] Figure 6 is a schematic cross-sectional view showing an interlayer for laminated glass according to the sixth embodiment of the present invention. In Figure 6, a cross-section in the thickness direction of the interlayer 11E is shown.

[0094] The interlayer 11E shown in Figure 6 comprises a first layer 1E. The interlayer 11E has a single-layer structure consisting only of the first layer 1E, and is a single-layer interlayer. The amount of thickness increase in the region where the thickness increases differs between the interlayer 11A and the interlayer 11E.

[0095] The interlayer 11E has a region where its thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the interlayer 11E has a portion where the increase in thickness decreases from one end 11a to the other end 11b. Furthermore, the interlayer 11E has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the interlayer 11E has a portion where the wedge angle decreases from one end to the other end.

[0096] The interlayer 11E and the first layer 1E have portions 11Ea, 1Ea with a rectangular cross-sectional shape in the thickness direction and portions 11Eb, 1Eb with a wedge-shaped cross-sectional shape in the thickness direction.

[0097] The above-mentioned interlayer preferably has a portion with a wedge-shaped cross-sectional shape in the thickness direction. The above-mentioned interlayer preferably has a portion in which the thickness gradually increases from one end to the other. The cross-sectional shape of the interlayer in the thickness direction is preferably wedge-shaped. Examples of cross-sectional shapes of the interlayer in the thickness direction include trapezoids, triangles, and pentagons.

[0098] From the viewpoint of further suppressing double images, it is preferable that the interlayer has a portion within the region where the thickness increases, where the increase in thickness is greater from one end to the other. From the viewpoint of further suppressing double images, it is preferable that the interlayer has a portion within the region where the cross-sectional shape in the thickness direction is wedge-shaped, where the wedge angle is greater from one end to the other.

[0099] To suppress double images, the wedge angle (θ) of the interlayer can be appropriately set according to the mounting angle of the laminated glass. The wedge angle (θ) is the wedge angle of the entire interlayer. From the viewpoint of further suppressing double images, the wedge angle (θ) of the interlayer is 0.1 mrad (0.00575 degrees) or more, preferably 0.2 mrad (0.0115 degrees) or more, preferably 2 mrad (0.1146 degrees) or less, and more preferably 0.7 mrad (0.0401 degrees) or less. The wedge angle (θ) of the interlayer is the interior angle at the intersection of a straight line connecting the surface portion on one side of the interlayer (first surface portion) between the maximum thickness portion and the minimum thickness portion of the interlayer, and a straight line connecting the surface portion on the other side of the interlayer (second surface portion) between the maximum thickness portion and the minimum thickness portion of the interlayer.

[0100] Furthermore, if there are multiple maximum thickness sections, multiple minimum thickness sections, a maximum thickness section within a certain region, or a minimum thickness section within a certain region, the maximum and minimum thickness sections for determining the wedge angle (θ) are selected in such a way that the resulting wedge angle (θ) is maximized.

[0101] The above wedge angle (θ) can be approximately calculated as follows: Measure the thickness of the interlayer at both the maximum thickness portion and the minimum thickness portion. Approximately calculate the wedge angle (θ) based on the result of (the absolute difference between the thickness at the maximum thickness portion and the thickness at the minimum thickness portion (μm) ÷ the distance from the maximum thickness portion to the minimum thickness portion (mm)).

[0102] The larger the wedge angle (θ) of the interlayer, the more likely it is that distortion will occur in the appearance of the laminated glass. In this invention, even if the wedge angle (θ) of the interlayer is large, it is possible to make it difficult for distortion to occur in the appearance of the laminated glass.

[0103] The thickness of the interlayer is not particularly limited. The thickness of the interlayer represents the total thickness of each layer constituting the interlayer. Therefore, in the case of a multilayer interlayer 11, the thickness of the interlayer represents the total thickness of the first layer 1, the second layer 2, and the third layer 3.

[0104] The maximum thickness of the interlayer is preferably 0.1 mm or more, more preferably 0.25 mm or more, even more preferably 0.5 mm or more, particularly preferably 0.8 mm or more, preferably 3 mm or less, more preferably 2 mm or less, and even more preferably 1.5 mm or less.

[0105] Examples of measuring instruments used to measure the wedge angle and thickness of the above-mentioned interlayer include the contact-type thickness gauge "TOF-4R" (manufactured by Yamabun Electric Co., Ltd.).

[0106] The above thickness measurement is performed using the measuring instrument described above, at a film transport speed of 2.15 to 2.25 mm / min, taking the shortest possible distance from one end to the other.

[0107] Appropriate measuring instruments are used to measure the wedge angle (θ) and thickness of the interlayer after the interlayer has been laminated into glass. Examples of such measuring instruments include the non-contact multilayer film thickness measuring instrument "OPTIGAUGE" (manufactured by Lumetrix). The thickness of the interlayer can be measured while the glass is still laminated.

[0108] Let X be the distance between one end and the other. Preferably, the interlayer has a minimum thickness in the region between 0X and 0.2X from one end inward, and a maximum thickness in the region between 0X and 0.2X from the other end inward. More preferably, the interlayer has a minimum thickness in the region between 0X and 0.1X from one end inward, and a maximum thickness in the region between 0X and 0.1X from the other end inward. Preferably, the interlayer has a minimum thickness at one end and a maximum thickness at the other end.

[0109] The interlayer films 11, 11A, 11B, 11C, 11D, and 11E have their maximum thickness at the other end 11b and their minimum thickness at one end 11a.

[0110] From a practical standpoint, as well as from the viewpoint of sufficiently improving adhesive strength and puncture resistance, the maximum thickness of the surface layer is preferably 0.001 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, preferably 1 mm or less, and more preferably 0.8 mm or less.

[0111] From a practical standpoint, and from the viewpoint of sufficiently improving penetration resistance, the maximum thickness of the layer (intermediate layer) placed between the two surface layers is preferably 0.001 mm or more, more preferably 0.1 mm or more, even more preferably 0.2 mm or more, preferably 0.8 mm or less, even more preferably 0.6 mm or less, and even more preferably 0.3 mm or less.

[0112] The distance X between one end and the other end of the interlayer is preferably 3 m or less, more preferably 2 m or less, particularly preferably 1.5 m or less, preferably 0.5 m or more, more preferably 0.8 m or more, and particularly preferably 1 m or more.

[0113] The following describes the details of the materials that make up each layer of the multilayer interlayer, as well as the single-layer interlayer.

[0114] (Thermoplastic Resin) The interlayer preferably contains a thermoplastic resin (hereinafter sometimes referred to as thermoplastic resin (0)). The interlayer preferably contains polyvinyl acetal resin (hereinafter sometimes referred to as polyvinyl acetal resin (0)) as thermoplastic resin (0). The first layer preferably contains a thermoplastic resin (hereinafter sometimes referred to as thermoplastic resin (1)). The first layer preferably contains polyvinyl acetal resin (hereinafter sometimes referred to as polyvinyl acetal resin (1)) as thermoplastic resin (1). The second layer preferably contains a thermoplastic resin (hereinafter sometimes referred to as thermoplastic resin (2)). The second layer preferably contains polyvinyl acetal resin (hereinafter sometimes referred to as polyvinyl acetal resin (2)) as thermoplastic resin (2). The third layer preferably contains a thermoplastic resin (hereinafter sometimes referred to as thermoplastic resin (3)). The third layer described above preferably contains polyvinyl acetal resin (hereinafter sometimes referred to as polyvinyl acetal resin (3)) as the thermoplastic resin (3). The thermoplastic resin (1), the thermoplastic resin (2), and the thermoplastic resin (3) may be the same or different. It is preferable that the thermoplastic resin (1) is different from the thermoplastic resin (2) and the thermoplastic resin (3) in order to further improve sound insulation. The polyvinyl acetal resin (1), the polyvinyl acetal resin (2), and the polyvinyl acetal resin (3) may be the same or different. It is preferable that the polyvinyl acetal resin (1) is different from the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) in order to further improve sound insulation. The thermoplastic resin (0), the thermoplastic resin (1), the thermoplastic resin (2), and the thermoplastic resin (3) may each be used individually or in combination of two or more. The polyvinyl acetal resin (0), polyvinyl acetal resin (1), polyvinyl acetal resin (2), and polyvinyl acetal resin (3) may be used individually or in combination of two or more types.

[0115] Examples of the thermoplastic resins mentioned above include polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, polyurethane resin, and polyvinyl alcohol resin. Other thermoplastic resins may also be used.

[0116] The thermoplastic resin is preferably polyvinyl acetal resin. The combined use of polyvinyl acetal resin and a plasticizer further enhances the adhesion of the layer containing the polyvinyl acetal resin and plasticizer to the laminated glass member or other layers.

[0117] The above-mentioned polyvinyl acetal resin can be produced, for example, by acetalizing polyvinyl alcohol (PVA) with an aldehyde. Preferably, the polyvinyl acetal resin is an acetalized product of polyvinyl alcohol. The polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate. The degree of saponification of the polyvinyl alcohol is generally in the range of 70 to 99.9 mol%.

[0118] The average degree of polymerization of the polyvinyl alcohol (PVA) is preferably 200 or higher, more preferably 500 or higher, even more preferably 1500 or higher, still more preferably 1600 or higher, particularly preferably 2600 or higher, most preferably 2700 or higher, preferably 5000 or lower, more preferably 4000 or lower, and still more preferably 3500 or lower. If the average degree of polymerization is above the lower limit, the penetration resistance of the laminated glass is further increased. If the average degree of polymerization is below the upper limit, the molding of the interlayer film becomes easier.

[0119] The average degree of polymerization of the above polyvinyl alcohol is determined by a method in accordance with JIS K6726 "Test Method for Polyvinyl Alcohol".

[0120] The number of carbon atoms in the acetal group contained in the above polyvinyl acetal resin is not particularly limited. The aldehyde used in the production of the above polyvinyl acetal resin is not particularly limited. The number of carbon atoms in the acetal group in the above polyvinyl acetal resin is preferably 3 to 5, and more preferably 3 or 4. When the number of carbon atoms in the acetal group in the above polyvinyl acetal resin is 3 or more, the glass transition temperature of the interlayer becomes sufficiently low.

[0121] The above aldehydes are not particularly limited. Generally, aldehydes having 1 to 10 carbon atoms are preferably used. Examples of the above aldehydes having 1 to 10 carbon atoms include propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, and benzaldehyde. Propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-hexylaldehyde, or n-valeraldehyde are preferred, propionaldehyde, n-butyraldehyde, or isobutyraldehyde are more preferred, and n-butyraldehyde is even more preferred. Only one of the above aldehydes may be used, or two or more may be used in combination.

[0122] The hydroxyl group content (amount of hydroxyl groups) of the polyvinyl acetal resin (0) is preferably 15 mol% or more, more preferably 18 mol% or more, preferably 40 mol% or less, and more preferably 35 mol% or less. If the hydroxyl group content is above the lower limit, the adhesive strength of the interlayer film is further increased. If the hydroxyl group content is below the upper limit, the flexibility of the interlayer film is increased, making it easier to handle.

[0123] The hydroxyl group content (amount of hydroxyl groups) of the polyvinyl acetal resin (1) is preferably 17 mol% or more, more preferably 20 mol% or more, even more preferably 22 mol% or more, preferably 28 mol% or less, more preferably 27 mol% or less, even more preferably 25 mol% or less, and particularly preferably 24 mol% or less. When the hydroxyl group content is above the lower limit, the mechanical strength of the interlayer film is further increased. In particular, when the hydroxyl group content of the polyvinyl acetal resin (1) is 20 mol% or more, the reaction efficiency is high and productivity is excellent, and when it is 28 mol% or less, the sound insulation of the laminated glass is further increased. Furthermore, when the hydroxyl group content is below the upper limit, the flexibility of the interlayer film is increased and the handling of the interlayer film becomes easier.

[0124] The hydroxyl group content of the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) is preferably 25 mol% or more, more preferably 28 mol% or more, more preferably 30 mol% or more, even more preferably 31.5 mol% or more, even more preferably 32 mol% or more, and particularly preferably 33 mol% or more. The hydroxyl group content of the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) is preferably 38 mol% or less, more preferably 37 mol% or less, even more preferably 36.5 mol% or less, and particularly preferably 36 mol% or less. When the hydroxyl group content is above the lower limit, the adhesive strength of the interlayer film is further increased. Also, when the hydroxyl group content is below the upper limit, the flexibility of the interlayer film is increased, making it easier to handle.

[0125] From the viewpoint of further improving sound insulation, it is preferable that the hydroxyl group content of the polyvinyl acetal resin (1) is lower than the hydroxyl group content of the polyvinyl acetal resin (2). From the viewpoint of further improving sound insulation, it is preferable that the hydroxyl group content of the polyvinyl acetal resin (1) is lower than the hydroxyl group content of the polyvinyl acetal resin (3). From the viewpoint of further improving sound insulation, the absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (2) is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 9 mol% or more, particularly preferably 10 mol% or more, and most preferably 12 mol% or more. From the viewpoint of further improving sound insulation, the absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (3) is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 9 mol% or more, particularly preferably 10 mol% or more, and most preferably 12 mol% or more. The absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (2), and the absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (3) is preferably 20 mol% or less.

[0126] The hydroxyl group content of the polyvinyl acetal resin described above is the mole fraction obtained by dividing the amount of ethylene groups to which hydroxyl groups are attached by the total amount of ethylene groups in the main chain, expressed as a percentage. The amount of ethylene groups to which hydroxyl groups are attached can be measured, for example, in accordance with JIS K6728 "Test Method for Polyvinyl Butyral".

[0127] The degree of acetylation (amount of acetyl groups) of the above polyvinyl acetal resin (0) is preferably 0.1 mol% or more, more preferably 0.3 mol% or more, even more preferably 0.5 mol% or more, preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less. When the degree of acetylation is above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is high. When the degree of acetylation is below the upper limit, the moisture resistance of the interlayer and laminated glass is high.

[0128] The degree of acetylation (amount of acetyl groups) of the polyvinyl acetal resin (1) is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, even more preferably 7 mol% or more, still more preferably 9 mol% or more, preferably 30 mol% or less, more preferably 25 mol% or less, still more preferably 24 mol% or less, and particularly preferably 20 mol% or less. When the degree of acetylation is above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is high. When the degree of acetylation is below the upper limit, the moisture resistance of the interlayer and laminated glass is high. In particular, when the degree of acetylation of the polyvinyl acetal resin (1) is 0.1 mol% or more and 25 mol% or less, the puncture resistance is excellent.

[0129] The degree of acetylation of the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) is preferably 0.01 mol% or more, more preferably 0.5 mol% or more, preferably 10 mol% or less, and more preferably 2 mol% or less. When the degree of acetylation is above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is high. When the degree of acetylation is below the upper limit, the moisture resistance of the interlayer and the laminated glass is high.

[0130] The degree of acetylation described above is a value expressed as a percentage of the mole fraction obtained by dividing the amount of ethylene groups to which acetyl groups are attached by the total amount of ethylene groups in the main chain. The amount of ethylene groups to which acetyl groups are attached can be measured, for example, in accordance with JIS K6728 "Test Method for Polyvinyl Butyral".

[0131] The degree of acetalization of the above polyvinyl acetal resin (0) (or the degree of butyralization in the case of polyvinyl butyral resin) is preferably 60 mol% or more, more preferably 63 mol% or more, preferably 85 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less. When the degree of acetalization is above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is increased. When the degree of acetalization is below the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0132] The degree of acetalization of the above polyvinyl acetal resin (1) (or the degree of butyralization in the case of polyvinyl butyral resin) is preferably 47 mol% or more, more preferably 60 mol% or more, 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 above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is increased. When the degree of acetalization is below the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0133] The degree of acetalization of the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) described above (or the degree of butyralization in the case of polyvinyl butyral resin) is preferably 55 mol% or more, more preferably 60 mol% or more, preferably 75 mol% or less, and more preferably 71 mol% or less. When the degree of acetalization is above the lower limit, the compatibility between the polyvinyl acetal resin and the plasticizer is increased. When the degree of acetalization is below the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0134] The degree of acetalization is determined as follows: The total amount of ethylene groups in the main chain is subtracted from the total amount of ethylene groups in the main chain by the amount of ethylene groups to which hydroxyl groups are attached and the amount of ethylene groups to which acetyl groups are attached. The resulting value is then divided by the total amount of ethylene groups in the main chain to obtain a mole fraction. This percentage represents the degree of acetalization.

[0135] Furthermore, it is preferable to calculate the above-mentioned hydroxyl group content (amount of hydroxyl groups), degree of acetalization (degree of butyralization), and degree of acetylation from the results measured by a method in accordance with JIS K6728 "Test Method for Polyvinyl Butyral". However, measurement by ASTM D1396-92 may also be used. If the polyvinyl acetal resin is polyvinyl butyral resin, the above-mentioned hydroxyl group content (amount of hydroxyl groups), degree of acetalization (degree of butyralization), and degree of acetylation can be calculated from the results measured by a method in accordance with JIS K6728 "Test Method for Polyvinyl Butyral".

[0136] The content of polyvinyl acetal resin in 100% by weight of thermoplastic resin contained in the interlayer is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, still more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The main component (50% by weight or more) of the thermoplastic resin in the above interlayer is preferably polyvinyl acetal resin.

[0137] (Plasticizer) From the viewpoint of further enhancing the adhesive strength of the interlayer, it is preferable that the interlayer contains a plasticizer (hereinafter sometimes referred to as plasticizer (0)). The first layer is preferably containing a plasticizer (hereinafter sometimes referred to as plasticizer (1)). The second layer is preferably containing a plasticizer (hereinafter sometimes referred to as plasticizer (2)). The third layer is preferably containing a plasticizer (hereinafter sometimes referred to as plasticizer (3)). When the thermoplastic resin contained in the interlayer is polyvinyl acetal resin, it is particularly preferable that the interlayer (each layer) contains a plasticizer. The layer containing polyvinyl acetal resin is preferably containing a plasticizer.

[0138] The plasticizer described above is not particularly limited. Conventionally known plasticizers can be used as the plasticizer. Only one type of plasticizer may be used, or two or more types may be used in combination.

[0139] Examples of the above-mentioned plasticizers include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and organic phosphate plasticizers such as organic phosphate plasticizers and organic phosphate plasticizers. The above-mentioned plasticizer is preferably an organic ester plasticizer. The above-mentioned plasticizer is preferably a liquid plasticizer.

[0140] Examples of the monobasic organic acid esters mentioned above include glycol esters obtained by the reaction of glycol with a monobasic organic acid. Examples of the glycols mentioned above include triethylene glycol, tetraethylene glycol, and tripropylene glycol. Examples of the monobasic organic acids mentioned above include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptylic acid, n-octylic acid, 2-ethylhexyl acid, n-nonylic acid, and decylic acid.

[0141] Examples of the above-mentioned polybasic organic acid esters include ester compounds of a polybasic organic acid and an alcohol having a linear or branched structure with 4 to 8 carbon atoms. Examples of the above-mentioned polybasic organic acids include adipic acid, sebacic acid, and azelaic acid.

[0142] The above organic ester plasticizers include triethylene glycol di-2-ethylpropanoate, triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethylbutyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate, and di Examples include ethylene glycol di-2-ethyl butyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethyl butyrate, diethylene glycol dicaprylate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, a mixture of heptyl adipate and nonyl adipate, diisononyl adipate, diisodecyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified alkyd sebacate, and a mixture of phosphate esters and adipic acid esters. Other organic ester plasticizers may also be used. Other adipic acid esters other than those mentioned above may also be used.

[0143] Examples of the above-mentioned organic phosphate plasticizers include tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

[0144] The above plasticizer is preferably a diester plasticizer represented by the following formula (1).

[0145]

[0146] In formula (1) above, R1 and R2 each represent an organic group having 5 to 10 carbon atoms, R3 represents an ethylene group, an isopropylene group, or an n-propylene group, and p represents an integer from 3 to 10. Preferably, R1 and R2 in formula (1) above are organic groups having 6 to 10 carbon atoms.

[0147] The above plasticizer preferably contains triethylene glycol di-2-ethylhexanoate (3GO) or triethylene glycol di-2-ethyl butyrate (3GH), and more preferably contains triethylene glycol di-2-ethylhexanoate.

[0148] In the above-mentioned interlayer film, the content of the plasticizer (0) relative to 100 parts by weight of the thermoplastic resin (0) is defined as content (0). The content (0) is preferably 25 parts by weight or more, more preferably 30 parts by weight or more, preferably 100 parts by weight or less, more preferably 60 parts by weight or less, and even more preferably 50 parts by weight or less. If the content (0) is above the lower limit, the penetration resistance of the laminated glass is further increased. If the content (0) is below the upper limit, the transparency of the interlayer film is further increased.

[0149] In the first layer described above, the content of the plasticizer (1) per 100 parts by weight of the thermoplastic resin (1) is defined as content (1). The content (1) is preferably 50 parts by weight or more, more preferably 55 parts by weight or more, even more preferably 60 parts by weight or more, preferably 100 parts by weight or less, more preferably 90 parts by weight or less, even more preferably 85 parts by weight or less, and particularly preferably 80 parts by weight or less. If the content (1) is above the lower limit, the flexibility of the interlayer film increases, making it easier to handle. If the content (1) is below the upper limit, the penetration resistance of the laminated glass is further increased.

[0150] In the second layer described above, the content of the plasticizer (2) per 100 parts by weight of the thermoplastic resin (2) is defined as content (2). In the third layer described above, the content of the plasticizer (3) per 100 parts by weight of the thermoplastic resin (3) is defined as content (3). The content (2) and content (3) are preferably 10 parts by weight or more, more preferably 15 parts by weight or more, even more preferably 20 parts by weight or more, particularly preferably 24 parts by weight or more, preferably 40 parts by weight or less, more preferably 35 parts by weight or less, even more preferably 32 parts by weight or less, and particularly preferably 30 parts by weight or less. When the content (2) and content (3) are above the lower limit, the flexibility of the interlayer film increases, making it easier to handle the interlayer film. When the content (2) and content (3) are below the upper limit, the penetration resistance of the laminated glass is further increased.

[0151] In order to improve the sound insulation of laminated glass, it is preferable that the amount of (1) is greater than the amount of (2), and it is preferable that the amount of (1) is greater than the amount of (3).

[0152] From the viewpoint of further improving the sound insulation properties of laminated glass, the absolute value of the difference between the above content (2) and the above content (1), and the absolute value of the difference between the above content (3) and the above content (1), are preferably 10 parts by weight or more, more preferably 15 parts by weight or more, and even more preferably 20 parts by weight or more. The absolute value of the difference between the above content (2) and the above content (1), and the absolute value of the difference between the above content (3) and the above content (1), are preferably 80 parts by weight or less, more preferably 75 parts by weight or less, and even more preferably 70 parts by weight or less.

[0153] (Heat-shielding substance) The interlayer preferably contains a heat-shielding substance. The first layer preferably contains a heat-shielding substance. The second layer preferably contains a heat-shielding substance. The third layer preferably contains a heat-shielding substance. Only one type of heat-shielding substance may be used, or two or more types may be used in combination.

[0154] The heat-shielding substance preferably contains at least one component X from among phthalocyanine compounds, naphthalocyanine compounds, and anthracianine compounds, or contains heat-shielding particles. In this case, the heat-shielding substance may contain both component X and heat-shielding particles.

[0155] Component X: The interlayer preferably contains at least one component X selected from phthalocyanine compounds, naphthalocyanine compounds, and anthracianine compounds. The first layer preferably contains component X. The second layer preferably contains component X. The third layer preferably contains component X. Component X is a heat-shielding substance. Only one type of component X may be used, or two or more types may be used in combination.

[0156] The above-mentioned component X is not particularly limited. Conventionally known phthalocyanine compounds, naphthalocyanine compounds, and anthracianine compounds can be used as component X.

[0157] Examples of component X include phthalocyanine, phthalocyanine derivatives, naphthalocyanine, naphthalocyanine derivatives, anthracianine, and anthracianine derivatives. It is preferable that the phthalocyanine compound and the phthalocyanine derivative each have a phthalocyanine skeleton. It is preferable that the naphthalocyanine compound and the naphthalocyanine derivative each have a naphthalocyanine skeleton. It is preferable that the anthracianine compound and the anthracianine derivative each have an anthracianine skeleton.

[0158] From the viewpoint of further improving the heat shielding properties of the interlayer and laminated glass, it is preferable that the above component X is at least one selected from the group consisting of phthalocyanine, phthalocyanine derivatives, naphthalocyanine, and naphthalocyanine derivatives, and more preferably at least one of phthalocyanine and phthalocyanine derivatives.

[0159] From the viewpoint of effectively enhancing heat shielding properties and maintaining visible light transmittance at an even higher level over a long period of time, it is preferable that component X contains a vanadium atom or a copper atom. It is preferable that component X contains a vanadium atom, and it is also preferable that it contains a copper atom. It is more preferable that component X is at least one of phthalocyanine containing a vanadium atom or a copper atom, and a derivative of phthalocyanine containing a vanadium atom or a copper atom. From the viewpoint of further enhancing the heat shielding properties of the interlayer and laminated glass, it is preferable that component X has a structural unit in which an oxygen atom is bonded to a vanadium atom.

[0160] In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned component X (first layer, second layer, or third layer), the content of component X is preferably 0.001% by weight or more, more preferably 0.005% by weight or more, even more preferably 0.01% by weight or more, and particularly preferably 0.02% by weight or more. In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned component X (first layer, second layer, or third layer), the content of component X is preferably 0.2% by weight or less, more preferably 0.1% by weight or less, even more preferably 0.05% by weight or less, and particularly preferably 0.04% by weight or less. When the content of component X is above the lower limit and below the upper limit, the heat shielding performance becomes sufficiently high and the visible light transmittance becomes sufficiently high. For example, it is possible to make the visible light transmittance 70% or more.

[0161] Heat-shielding particles: The interlayer preferably contains heat-shielding particles. The first layer preferably contains heat-shielding particles. The second layer preferably contains heat-shielding particles. The third layer preferably contains heat-shielding particles. The heat-shielding particles are heat-shielding materials. By using heat-shielding particles, infrared rays (heat rays) can be effectively blocked. Only one type of heat-shielding particle may be used, or two or more types may be used in combination.

[0162] From the viewpoint of further enhancing the heat-shielding properties of laminated glass, it is more preferable that the heat-shielding particles are metal oxide particles. It is preferable that the heat-shielding particles are particles formed from metal oxides (metal oxide particles).

[0163] Infrared rays with wavelengths longer than visible light (780 nm and above) have less energy than ultraviolet rays. However, infrared rays have a strong thermal effect, and when they are absorbed by a substance, they are emitted as heat. For this reason, infrared rays are generally called heat rays. By using the heat-shielding particles mentioned above, infrared rays (heat rays) can be effectively blocked. Note that heat-shielding particles refer to particles that can absorb infrared rays.

[0164] Specific examples of the above heat-shielding particles include metal oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, antimond-doped tin oxide particles (ATO particles), gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminum-doped zinc oxide particles (AZO particles), niobium-doped titanium oxide particles, sodium-doped tungsten oxide particles, cesium-doped tungsten oxide particles, thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, tin-doped indium oxide particles (ITO particles), tin-doped zinc oxide particles, silicon-doped zinc oxide particles, and lanthanum hexaboride (LaB ６ Examples include particles such as ) and tungsten oxide particles. Other heat-shielding particles may also be used. Metal oxide particles are preferred because they have a high heat-shielding function, ATO particles, GZO particles, IZO particles, ITO particles, or tungsten oxide particles are more preferred, ATO particles, ITO particles, or tungsten oxide particles are even more preferred, and ITO particles or tungsten oxide particles are particularly preferred. When the above heat-shielding particles include ITO particles or tungsten oxide particles, the above heat-shielding particles may include ITO particles and tungsten oxide particles. In particular, tin-doped indium oxide particles (ITO particles) are preferred because they have a high heat-shielding function and are readily available, and tungsten oxide particles are also preferred.

[0165] From the viewpoint of further improving the heat shielding properties of the interlayer and laminated glass, it is preferable that the tungsten oxide particles are metal-doped tungsten oxide particles. The above-mentioned "tungsten oxide particles" include metal-doped tungsten oxide particles. Specifically, examples of the above-mentioned metal-doped tungsten oxide particles include sodium-doped tungsten oxide particles, cesium-doped tungsten oxide particles, thallium-doped tungsten oxide particles, and rubidium-doped tungsten oxide particles.

[0166] From the viewpoint of further improving the heat shielding properties of the interlayer and laminated glass, cesium-doped tungsten oxide particles are particularly preferred. From the viewpoint of further improving the heat shielding properties of the interlayer and laminated glass, the cesium-doped tungsten oxide particles are of formula: Cs ０．３３ WO ３ Preferably, the particles are tungsten oxide particles represented by [formula].

[0167] The average particle diameter of the heat-shielding particles is preferably 0.01 μm or more, more preferably 0.02 μm or more, more preferably 0.1 μm or less, and more preferably 0.05 μm or less. If the average particle diameter is above the lower limit, the heat-shielding performance becomes sufficiently high. If the average particle diameter is below the upper limit, the dispersibility of the heat-shielding particles becomes high.

[0168] The "average particle diameter" mentioned above refers to the volume-average particle diameter. The average particle diameter can be measured using a particle size distribution analyzer (such as the "UPA-EX150" manufactured by Nikkiso Co., Ltd.).

[0169] In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned heat-shielding particles (first layer, second layer, or third layer), the content of the above-mentioned heat-shielding particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, even more preferably 1% by weight or more, and particularly preferably 1.5% by weight or more. In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned heat-shielding particles (first layer, second layer, or third layer), the content of the above-mentioned heat-shielding particles is preferably 6% by weight or less, more preferably 5.5% by weight or less, even more preferably 4% by weight or less, particularly preferably 3.5% by weight or less, and most preferably 3% by weight or less. When the content of the above-mentioned heat-shielding particles is above the lower limit and below the upper limit, the heat-shielding performance becomes sufficiently high and the visible light transmittance becomes sufficiently high.

[0170] (Metal Salts) The interlayer preferably contains at least one metal salt (hereinafter sometimes referred to as metal salt M) from among alkali metal salts, alkaline earth metal salts, and magnesium salts. The first layer preferably contains metal salt M. The second layer preferably contains metal salt M. The third layer preferably contains metal salt M. The use of metal salt M makes it easy to control the adhesion between the interlayer and a laminated glass member such as a glass plate, or the adhesion between each layer in the interlayer. Only one type of metal salt M may be used, or two or more types may be used in combination.

[0171] The above metal salt M preferably contains at least one metal selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba. The metal salt contained in the interlayer preferably contains at least one metal from K and Mg.

[0172] Furthermore, the above-mentioned metal salt M is more preferably an alkali metal salt of an organic acid having 2 to 16 carbon atoms, an alkaline earth metal salt of an organic acid having 2 to 16 carbon atoms, or a magnesium salt of an organic acid having 2 to 16 carbon atoms, and even more preferably a magnesium carboxylate salt of an organic acid having 2 to 16 carbon atoms or a potassium carboxylate salt of an organic acid having 2 to 16 carbon atoms.

[0173] Examples of magnesium carboxylate salts having 2 to 16 carbon atoms and potassium carboxylate salts having 2 to 16 carbon atoms include magnesium acetate, potassium acetate, magnesium propionate, potassium propionate, magnesium 2-ethylbutyrate, potassium 2-ethylbutanoate, magnesium 2-ethylhexanoate, and potassium 2-ethylhexanoate.

[0174] The total content of Mg and K in the interlayer containing the above-mentioned metal salt M, or in the layer (first layer, second layer, or third layer) containing the above-mentioned metal salt M, is preferably 5 ppm or more, more preferably 10 ppm or more, even more preferably 20 ppm or more, preferably 300 ppm or less, more preferably 250 ppm or less, and even more preferably 200 ppm or less. When the total content of Mg and K is above the lower limit and below the upper limit, the adhesion between the interlayer and the glass plate, or the adhesion between each layer in the interlayer, can be controlled to be even better.

[0175] (UV shielding agent) The interlayer preferably contains a UV shielding agent. The first layer preferably contains a UV shielding agent. The second layer preferably contains a UV shielding agent. The third layer preferably contains a UV shielding agent. The use of a UV shielding agent makes it less likely for the visible light transmittance to decrease even after the interlayer and laminated glass have been used for a long period of time. Only one type of UV shielding agent may be used, or two or more types may be used in combination.

[0176] The above-mentioned UV shielding agent includes a UV absorber. Preferably, the above-mentioned UV shielding agent is a UV absorber.

[0177] Examples of the above-mentioned ultraviolet shielding agents include ultraviolet shielding agents containing metal atoms, ultraviolet shielding agents containing metal oxides, ultraviolet shielding agents having a benzotriazole structure (benzotriazole compounds), ultraviolet shielding agents having a benzophenone structure (benzophenone compounds), ultraviolet shielding agents having a triazine structure (triazine compounds), ultraviolet shielding agents having a malonic acid ester structure (malonic acid ester compounds), ultraviolet shielding agents having an oxalic acid anilide structure (oxalic acid anilide compounds), and ultraviolet shielding agents having a benzoate structure (benzoate compounds).

[0178] Examples of ultraviolet shielding agents containing the above-mentioned metal atoms include platinum particles, particles in which the surface of platinum particles is coated with silica, palladium particles, and particles in which the surface of palladium particles is coated with silica. It is preferable that the ultraviolet shielding agent is not a heat-shielding particle.

[0179] The above ultraviolet shielding agent is preferably an ultraviolet shielding agent having a benzotriazole structure, an ultraviolet shielding agent having a benzophenone structure, an ultraviolet shielding agent having a triazine structure, or an ultraviolet shielding agent having a benzoate structure. The above ultraviolet shielding agent is more preferably an ultraviolet shielding agent having a benzotriazole structure or an ultraviolet shielding agent having a benzophenone structure, and even more preferably an ultraviolet shielding agent having a benzotriazole structure.

[0180] Examples of UV shielding agents containing the above-mentioned metal oxides include zinc oxide, titanium oxide, and cerium oxide. Furthermore, the surface of the UV shielding agent containing the above-mentioned metal oxide may be coated. Examples of coating materials for the surface of the UV shielding agent containing the above-mentioned metal oxides include insulating metal oxides, hydrolyzable organosilicon compounds, and silicone compounds.

[0181] Examples of the insulating metal oxides mentioned above include silica, alumina, and zirconia. These insulating metal oxides have, for example, a band gap energy of 5.0 eV or more.

[0182] Examples of UV-blocking agents having the above-mentioned benzotriazole structure include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (BASF's "Tinuvin P"), 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole (BASF's "Tinuvin 320"), 2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole (BASF's "Tinuvin 326"), and 2-(2'-hydroxy-3',5'-diamylphenyl)benzotriazole (BASF's "Tinuvin 328"). Because they exhibit excellent UV-blocking performance, the above-mentioned UV-blocking agents are preferably UV-blocking agents having a benzotriazole structure containing a halogen atom, and more preferably UV-blocking agents having a benzotriazole structure containing a chlorine atom.

[0183] Examples of UV-blocking agents having the above-mentioned benzophenone structure include octabenzone (BASF's "Chimassorb 81").

[0184] Examples of UV shielding agents having the above triazine structure include "LA-F70" manufactured by ADEKA Corporation and 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol ("Tinuvin 1577FF" manufactured by BASF Corporation).

[0185] Examples of UV shielding agents having the above-mentioned malonic acid ester structure include dimethyl 2-(p-methoxybenzylidene)malonate, tetraethyl-2,2-(1,4-phenylenedimethylidene)bismalonate, and 2-(p-methoxybenzylidene)-bis(1,2,2,6,6-pentamethyl4-piperidinyl)malonate.

[0186] Examples of commercially available UV-blocking agents having the above-mentioned malonic acid ester structure include Hostavin B-CAP, Hostavin PR-25, and Hostavin PR-31 (all manufactured by Clariant).

[0187] Examples of UV shielding agents having the above-mentioned oxalic acid anilide structure include oxalic acid diamides having an aryl group substituted on the nitrogen atom, such as N-(2-ethylphenyl)-N'-(2-ethoxy-5-t-butylphenyl)oxalic acid diamide, N-(2-ethylphenyl)-N'-(2-ethoxy-phenyl)oxalic acid diamide, and 2-ethyl-2'-ethoxy-oxyanilide (Sanduvor VSU, manufactured by Clariant).

[0188] Examples of UV-blocking agents having the above-mentioned benzoate structure include 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (BASF's "Tinuvin 120").

[0189] In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned ultraviolet shielding agent (first layer, second layer, or third layer), the content of the ultraviolet shielding agent is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, even more preferably 0.3% by weight or more, and particularly preferably 0.5% by weight or more. In 100% by weight of the above-mentioned interlayer film or in 100% by weight of the layer containing the above-mentioned ultraviolet shielding agent (first layer, second layer, or third layer), the content of the ultraviolet shielding agent is preferably 2.5% by weight or less, more preferably 2% by weight or less, even more preferably 1% by weight or less, and particularly preferably 0.8% by weight or less. When the content of the above-mentioned ultraviolet shielding agent is above the lower limit and below the upper limit, the decrease in visible light transmittance after a period of time can be further suppressed. In particular, by ensuring that the amount of the UV shielding agent in the layer containing the UV shielding agent is 0.2% by weight or more in 100% by weight, the decrease in the visible light transmittance of the interlayer and laminated glass after a period of time can be significantly suppressed.

[0190] (Antioxidant) The above-mentioned interlayer preferably contains an antioxidant. The above-mentioned first layer preferably contains an antioxidant. The above-mentioned second layer preferably contains an antioxidant. The above-mentioned third layer preferably contains an antioxidant. Only one type of antioxidant may be used, or two or more types may be used in combination.

[0191] Examples of the above-mentioned antioxidants include phenolic antioxidants, sulfuric antioxidants, and phosphorusic antioxidants. The phenolic antioxidant is an antioxidant having a phenol skeleton. The sulfuric antioxidant is an antioxidant containing a sulfur atom. The phosphorusic antioxidant is an antioxidant containing a phosphorus atom.

[0192] The above antioxidant is preferably a phenolic antioxidant or a phosphorus-based antioxidant.

[0193] The above phenolic antioxidants include 2,6-di-t-butyl-p-cresol (BHT), butylhydroxyanisole (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), and 1,1,3-tris-(2-methyl-hydroxy-5- Examples include t-butylphenyl)butane, 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)butyric acid glycol ester, and bis(3-t-butyl-4-hydroxy-5-methylbenzenepropanoic acid)ethylenebis(oxyethylene). One or more of these antioxidants are preferably used.

[0194] Examples of the phosphorus-based antioxidants mentioned above include tridecyl phosphite, tris(tridecyl) phosphite, triphenyl phosphite, trinonylphenyl phosphite, bis(tridecyl)pentaerythritol diphosphite, bis(decyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl) phosphite, bis(2,4-di-t-butyl-6-methylphenyl) ethyl ester phosphorous acid, and 2,2'-methylenebis(4,6-di-t-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus. One or more of these antioxidants are preferably used.

[0195] Examples of commercially available antioxidants include BASF's "IRGANOX 245," "IRGAFOS 168," and "IRGAFOS 38," Sumitomo Chemical's "SumiLizer BHT," Sakai Chemical Industry's "H-BHT," and BASF's "IRGANOX 1010."

[0196] In order to maintain the high visible light transmittance of the interlayer and laminated glass over a long period of time, it is preferable that the content of the antioxidant in 100% by weight of the interlayer or in 100% by weight of the layer containing the antioxidant (first layer, second layer, or third layer) is 0.1% by weight or more. Furthermore, since the effect of adding the antioxidant becomes saturated, it is preferable that the content of the antioxidant in 100% by weight of the interlayer or in 100% by weight of the layer containing the antioxidant is 2% by weight or less.

[0197] (Other components) The interlayer, the first layer, the second layer, and the third layer may each contain additives as needed, such as coupling agents, dispersants, surfactants, flame retardants, antistatic agents, pigments, dyes, adhesion modifiers other than metal salts, moisture-resistant agents, fluorescent whitening agents, and infrared absorbers. These additives may be used individually or in combination of two or more.

[0198] (Laminated glass) Figure 7 is a cross-sectional view showing an example of laminated glass using the interlayer for laminated glass shown in Figure 1.

[0199] The laminated glass 21 shown in Figure 7 comprises an interlayer 11, a first laminated glass member 22, and a second laminated glass member 23. The interlayer 11 is positioned and sandwiched between the first laminated glass member 22 and the second laminated glass member 23. The first laminated glass member 22 is positioned on the first surface of the interlayer 11. The second laminated glass member 23 is positioned on the second surface of the interlayer 11, opposite to the first surface.

[0200] Examples of the laminated glass members mentioned above include glass plates and PET (polyethylene terephthalate) films. The laminated glass includes not only laminated glass in which an interlayer is sandwiched between two glass plates, but also laminated glass in which an interlayer is sandwiched between a glass plate and a PET film or the like. Laminated glass is a laminate comprising glass plates, and it is preferable that at least one glass plate is used. It is preferable that the first laminated glass member and the second laminated glass member are each glass plates or PET (polyethylene terephthalate) films, and that the interlayer includes at least one glass plate as the first laminated glass member and the second laminated glass member. It is particularly preferable that both the first laminated glass member and the second laminated glass member are glass plates.

[0201] Examples of the above-mentioned glass plates include inorganic glass and organic glass. Examples of the above-mentioned inorganic glass include float glass, heat-absorbing glass, heat-reflective glass, polished glass, patterned glass, wired glass, and green glass. Examples of the above-mentioned organic glass include synthetic resin glass that can be used as an alternative to inorganic glass. Examples of the above-mentioned organic glass include polycarbonate sheets and poly(meth)acrylic resin sheets. Examples of the above-mentioned poly(meth)acrylic resin sheets include polymethyl (meth)acrylate sheets.

[0202] The thickness of the first laminated glass member and the second laminated glass member described above is not particularly limited, but is preferably 1 mm or more, and preferably 5 mm or less. When the laminated glass member is a glass plate, the thickness of the glass plate is preferably 1 mm or more, and preferably 5 mm or less. When the laminated glass member is a PET film, the thickness of the PET film is preferably 0.03 mm or more, and preferably 0.5 mm or less.

[0203] The method for manufacturing the laminated glass described above is not particularly limited. For example, the interlayer film is sandwiched between the first and second laminated glass members and passed through a pressing roll or placed in a rubber bag and subjected to reduced pressure suction. This removes the air remaining between the first laminated glass member and the interlayer film, and between the second laminated glass member and the interlayer film. After that, the laminate is pre-bonded at approximately 70 to 110°C to obtain a laminate. Next, the laminate is placed in an autoclave or pressed and compressed at approximately 120 to 150°C and a pressure of 1 to 1.5 MPa. In this way, laminated glass can be obtained.

[0204] The above-mentioned laminated glass can be used in automobiles, railway vehicles, aircraft, ships, and buildings. Preferably, the laminated glass is for building use or vehicle use, and more preferably for vehicle use. The above-mentioned laminated glass can also be used for applications other than those listed above. It can be used in the windshield, side windows, rear windows, or roof windows of automobiles. Because it has high heat shielding properties and high visible light transmittance, the above-mentioned laminated glass is suitable for use in automobiles.

[0205] Preferably, the laminated glass described above is a laminated glass that functions as a head-up display (HUD). In this HUD-function laminated glass, measurement information such as speed transmitted from the control unit can be projected onto the windshield from the instrument panel's display unit. This allows the driver of the vehicle to simultaneously view the forward view and the measurement information without having to lower their field of vision.

[0206] A head-up display system can be obtained using the above-described head-up display. The head-up display system comprises the laminated glass and a light source device for irradiating the laminated glass with light for image display. The light source device can be mounted, for example, on the dashboard of a vehicle. By irradiating the display area of ​​the laminated glass with light from the light source device, an image can be displayed.

[0207] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to these examples.

[0208] In the polyvinyl acetal resin used, n-butyraldehyde with 4 carbon atoms was used for acetalization. For the polyvinyl acetal resin, the degree of acetalization (degree of butyralization), degree of acetylation, and hydroxyl group content were measured according to the method specified in JIS K6728 "Test Method for Polyvinyl Butyral". Measurements using ASTM D1396-92 also yielded similar values ​​to those obtained using the method specified in JIS K6728 "Test Method for Polyvinyl Butyral".

[0209] (Example 1) Preparation of a composition for forming an interlayer (first layer): The following components were blended and thoroughly kneaded with a mixing roll to obtain a composition for forming an interlayer.

[0210] 100 parts by weight of polyvinyl acetal resin (average degree of polymerization 1700, hydroxyl group content 30.5 mol%, degree of acetylation 1.0 mol%, degree of acetalization 68.5 mol%) 40 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, BASF "Tinuvin 326") in an amount that constitutes 0.2% by weight in the resulting intermediate film BHT (2,6-di-t-butyl-p-cresol) in an amount that constitutes 0.2% by weight in the resulting intermediate film

[0211] Interlayer preparation: The extrusion temperature was adjusted so that the interlayer would take the desired outer shape, and the composition for forming the interlayer (first layer) was co-extruded using an extruder. At this time, the lip clearance at the tip of the mold was adjusted to control the thickness of the interlayer. A wedge-shaped interlayer having a structure consisting only of the first layer was prepared.

[0212] The resulting interlayer had a minimum thickness at one end and a maximum thickness at the other end. The distance X between the two ends was 105 cm.

[0213] In Example 1, an interlayer was fabricated in which the region of increasing thickness had a portion where the increase in thickness was greater from one end to the other, and the region with a wedge-shaped cross-section in the thickness direction had a portion where the wedge angle was larger from one end to the other (see Figure 3 for the shape of the outer shell). When the distance between one end and the other was X, the deepest part of the recess of the interlayer was located at a position of 0.3X from one end. The wedge angle of the entire interlayer was 0.50 mrad.

[0214] (Comparative Example 1) An interlayer was obtained in the same manner as in Example 1, except that the lip clearance at the tip of the mold during extrusion of the interlayer was not adjusted. In Comparative Example 1, the same types of UV shielding agent and antioxidant as in Example 1 were blended in the same amounts (content in the interlayer) as in Example 1.

[0215] (Example 4) An interlayer was obtained in the same manner as in Example 1, except that the extrusion temperature was adjusted so that the interlayer took the desired outer shape. In Example 4, the same types of UV shielding agent and antioxidant as in Example 1 were added in the same amounts (content in the interlayer) as in Example 1.

[0216] In Example 4, an interlayer was fabricated in which, within the region where the thickness increases, there is a portion where the increase in thickness decreases from one end to the other, and within the region where the cross-sectional shape in the thickness direction is wedge-shaped, there is a portion where the wedge angle decreases from one end to the other (see Figure 5 for the shape of the outer shell). When the distance between one end and the other is X, the most protruding part of the convex portion of the interlayer was located at a position of 0.3X from one end. The wedge angle of the entire interlayer was 0.50 mrad.

[0217] (Comparative Example 4) An interlayer was obtained in the same manner as in Example 4, except that the lip clearance at the tip of the mold during extrusion of the interlayer was not adjusted. In Comparative Example 4, the same type of UV shielding agent and antioxidant as in Example 1 were blended in the same amounts (content in the interlayer) as in Example 1.

[0218] (Example 2) Preparation of composition for forming the first layer: The following components were blended and thoroughly kneaded with a mixing roll to obtain a composition for forming the first layer.

[0219] 100 parts by weight of polyvinyl acetal resin (average degree of polymerization 3000, hydroxyl group content 22 mol%, degree of acetylation 13 mol%, degree of acetalization 65 mol%) 60 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, BASF "Tinuvin 326") in an amount that constitutes 0.2% by weight in the resulting first layer BHT (2,6-di-t-butyl-p-cresol) in an amount that constitutes 0.2% by weight in the resulting first layer

[0220] Preparation of compositions for forming the second and third layers: The following components were blended and thoroughly kneaded with a mixing roll to obtain compositions for forming the second and third layers.

[0221] 100 parts by weight of polyvinyl acetal resin (average degree of polymerization 1700, hydroxyl group content 30.5 mol%, degree of acetylation 1 mol%, degree of acetalization 68.5 mol%) 38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, BASF "Tinuvin 326") in an amount that constitutes 0.2% by weight in the resulting second and third layers BHT (2,6-di-t-butyl-p-cresol) in an amount that constitutes 0.2% by weight in the resulting second and third layers

[0222] Interlayer preparation: The extrusion temperature was adjusted so that the interlayer took the desired outer shape, and the composition for forming the first layer and the compositions for forming the second and third layers were co-extruded using a co-extruder. At this time, the lip clearance at the tip of the mold was adjusted to control the thickness of the interlayer. A wedge-shaped interlayer having a laminated structure of the second layer / first layer / third layer was prepared.

[0223] The resulting interlayer had a minimum thickness at one end and a maximum thickness at the other end. The distance X between the two ends was 107 cm.

[0224] In Example 2, an interlayer was fabricated in which the region of increasing thickness had a portion where the increase in thickness was greater from one end to the other, and the region with a wedge-shaped cross-section in the thickness direction had a portion where the wedge angle was larger from one end to the other (see Figure 3 for the shape of the outer shell). When the distance between one end and the other was X, the deepest part of the recess of the interlayer was located at a position of 0.3X from one end. The wedge angle of the entire interlayer was 0.30 mrad.

[0225] (Example 3) An interlayer was obtained in the same manner as in Example 2, except that the wedge angle of the entire interlayer was changed to 0.70 mrad and the distance X between one end and the other end was changed to 102 cm.

[0226] (Comparative Example 2) An interlayer was obtained in the same manner as in Example 2, except that the lip clearance at the tip of the mold during extrusion of the interlayer was not adjusted. In Comparative Example 2, the same types of UV shielding agent and antioxidant as in Example 2 were blended in the same amounts (content in the interlayer) as in Example 2.

[0227] (Comparative Example 3) An interlayer was obtained in the same manner as in Example 3, except that the lip clearance at the tip of the mold during extrusion of the interlayer was not adjusted. In Comparative Example 3, the same type of UV shielding agent and antioxidant as in Example 2 were blended in the same amounts (content in the interlayer) as in Example 2.

[0228] (Example 5) An interlayer was obtained in the same manner as in Example 2, except that the extrusion temperature was adjusted so that the interlayer took the desired outer shape. In Example 5, the same types of UV shielding agent and antioxidant as in Example 2 were added in the same amounts (content in the interlayer) as in Example 2.

[0229] In Example 5, an interlayer was fabricated in which, within the region where the thickness increases, there is a portion where the increase in thickness decreases from one end to the other, and within the region where the cross-sectional shape in the thickness direction is wedge-shaped, there is a portion where the wedge angle decreases from one end to the other (see Figure 5 for the shape of the outer shell). When the distance between one end and the other is X, the most protruding part of the convex portion of the interlayer was located at a position of 0.3X from one end. The wedge angle of the entire interlayer was 0.30 mrad.

[0230] (Example 6) An interlayer was obtained in the same manner as in Example 5, except that the wedge angle of the entire interlayer was changed to 0.70 mrad. In Example 6, the same type of UV shielding agent and antioxidant as in Example 2 were blended in the same amounts (content in the interlayer) as in Example 2.

[0231] (Comparative Example 5) An interlayer was obtained in the same manner as in Example 5, except that the lip clearance at the tip of the mold during extrusion of the interlayer was not adjusted. In Comparative Example 5, the same type of UV shielding agent and antioxidant as in Example 2 were blended in the same amounts (content in the interlayer) as in Example 2.

[0232] (Comparative Example 6) An intermediate film was obtained in the same manner as in Example 6, except that the lip clearance at the tip of the mold during extrusion of the intermediate film was not adjusted. In Comparative Example 6, the same type of ultraviolet shielding agent and antioxidant as in Example 2 were blended in the same amounts (content in the intermediate film) as in Example 2.

[0233] (Evaluation) (1) Measurement of partial wedge angle The above partial wedge angle was measured. The absolute value A was determined for all sections A at 150 mm intervals. The largest absolute value A and the smallest absolute value A were determined for all sections A at 150 mm intervals.

[0234] (2) Distortion in the appearance of laminated glass Laminated glass was fabricated by bonding an interlayer between glass plates. The laminated glass was tilted at a 45° angle, and light was shone onto the tilted laminated glass from a strong light source 3m away. The transmitted image was projected onto a screen approximately 2m away to evaluate the distortion in the appearance of the laminated glass. The distortion in the appearance of the laminated glass was judged according to the following criteria. The higher the numerical value of the criteria for judging the distortion in the appearance of the laminated glass, the more the distortion in the appearance of the laminated glass is suppressed.

[0235] [Criteria for determining distortion in the appearance of laminated glass] 4: No pattern visible at all 3: Pattern faintly visible 2: Wavy pattern can be seen 1: Wavy pattern can be seen, and variations in shading can be recognized 0: Variations in shading similar to the shadow at the edge of the glass can be seen -1: Bright lines are visible

[0236] Details and results are shown in Tables 1 and 2 below.

[0237]

[0238]

[0239] Furthermore, the laminated glass using the interlayers obtained in Examples 2, 3, 5, and 6 was evaluated for sound insulation performance based on acoustic transmission loss, and it was confirmed that it exhibited excellent sound insulation properties. In addition, the interlayers obtained in Examples 4 to 6 did not wrinkle or misalign when rolled, demonstrating excellent handling properties.

[0240] 1, 1A, 1B, 1C, 1D, 1E... First layer 1Aa, 1Ca, 1Ea... Part with a rectangular cross-sectional shape in the thickness direction 1Ab, 1Cb, 1Eb... Part with a wedge-shaped cross-sectional shape in the thickness direction 2, 2B, 2D... Second layer 3, 3B, 3D... Third layer 11, 11A, 11B, 11C, 11D, 11E... Interlayer 11a... One end 11b... Other end 11Aa, 11Ca, 11Ea... Part with a rectangular cross-sectional shape in the thickness direction 11Ab, 11Cb, 11Eb... Part with a wedge-shaped cross-sectional shape in the thickness direction 21... Laminated glass 22... First laminated glass member 23... Second laminated glass member R1... Display area R2... Surrounding area R3... Shade area 51... Roll body 61... Core

Claims

1. An interlayer film for laminated glass having one end and another end opposite the one end, the thickness of the other end being greater than the thickness of the one end, the wedge angle of the entire interlayer film being 0.1 mrad or greater, and in the measurement of the partial wedge angle described below, the absolute value A described below in all sections A every 150 mm is 0.4 mrad or less. Measurement of partial wedge angle: The partial wedge angle is measured in the order of 1 to 4 below. 1: Points A are selected at 2 mm intervals, with the starting point being a position 20 cm from one end of the interlayer film toward the other end and the ending point being a position 20 cm from the other end of the interlayer film toward the one end. 2: The partial wedge angle A is calculated for each partial region A of 40 mm in the direction connecting the one end and the other end, with each point A as the center. 3: Sections A are set every 150 mm from the starting point toward the ending point. 4: In each section A, the maximum and minimum values ​​of all partial wedge angles A in the partial region A in which point A exists within the section A are selected, and the absolute value A of the difference between the maximum and minimum values ​​is calculated.

2. The interlayer film for laminated glass according to claim 1, which is used in laminated glass that is a head-up display, and has a display-corresponding area that corresponds to the display area of ​​the head-up display.

3. The interlayer film for laminated glass according to claim 1 or 2, which contains a thermoplastic resin.

4. The interlayer film for laminated glass according to any one of claims 1 to 3, which contains a plasticizer.

5. The interlayer film for laminated glass according to any one of claims 1 to 4, comprising: a first layer; and a second layer disposed on the first surface side of the first layer.

6. The interlayer film for laminated glass according to claim 5, wherein the first layer contains a polyvinyl acetal resin; the second layer contains a polyvinyl acetal resin; and the hydroxyl group content of the polyvinyl acetal resin in the first layer is lower than the hydroxyl group content of the polyvinyl acetal resin in the second layer.

7. The interlayer film for laminated glass according to claim 5 or 6, wherein the first layer comprises a polyvinyl acetal resin, the second layer comprises a polyvinyl acetal resin, the first layer comprises a plasticizer, and the second layer comprises a plasticizer, and the content of the plasticizer in the first layer per 100 parts by weight of the polyvinyl acetal resin in the first layer is greater than the content of the plasticizer in the second layer per 100 parts by weight of the polyvinyl acetal resin in the second layer.

8. The interlayer film for laminated glass according to any one of claims 1 to 7, which has a portion whose cross section in the thickness direction is wedge-shaped within a region extending from a position 18 cm from one end toward the other end to a position 61.8 cm from one end toward the other end.

9. A laminated glass comprising: a first laminated glass element; a second laminated glass element; and the interlayer film for laminated glass according to any one of claims 1 to 8, wherein the interlayer film for laminated glass is disposed between the first laminated glass element and the second laminated glass element.