Interlayer for glass laminate, roll body and glass laminate

Abstract

To provide an interlayer for a glass laminate capable of inhibiting a transmitting double image in a glass laminate.SOLUTION: An interlayer for a glass laminate includes one end and the other end on an opposite side of the one end. The other end is thicker than the one end. According to a calculation of a formula of a specific approximation straight line A and a deviation of a partial wedge angle, when a tilt of the approximation straight line A and a maximum value of an absolute value of the deviation of the partial wedge angle are calculated, at least in one interval A, the tilt of the approximation straight line A is -0.05 mrad / m or less, and the maximum value of the absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an interlayer film for laminated glass used to obtain laminated glass. The present invention also relates to a roll body and laminated glass using the interlayer film for laminated glass. [Background technology]

[0002] Even if laminated glass is broken by an external impact, the amount of glass fragments scattered is small, and therefore, laminated glass is excellent in safety. For this reason, the laminated glass is widely used in automobiles, railroad cars, aircraft, ships, buildings, etc. The laminated glass is manufactured by sandwiching an interlayer film for laminated glass between two glass sheets.

[0003] A head-up display (HUD) is also known as an example of the laminated glass used in automobiles. HUDs can display measurement information, such as the speed of an automobile, which is driving data, on the windshield of the automobile, and the driver can recognize the display as if it were projected on the front of the windshield.

[0004] The above HUD has a problem in that measurement information, etc. is seen double.

[0005] In order to suppress double images, a wedge-shaped interlayer is used. The following Patent Document 1 discloses a laminated glass in which a wedge-shaped interlayer having a predetermined wedge angle is sandwiched between a pair of glass plates. In such laminated glass, the wedge angle of the interlayer can be adjusted to connect the display of measurement information reflected by one glass plate and the display of measurement information reflected by another glass plate to one point in the driver's field of vision. Therefore, the display of measurement information is unlikely to be seen as double, and the driver's field of vision is unlikely to be obstructed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 4-502525 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventionally, the wedge angle of the interlayer has been adjusted to suppress double images. However, simply adjusting the wedge angle of the interlayer may not be enough to suppress transmitted double images in laminated glass. Transmitted double images are a phenomenon in which a double image is observed due to the illumination of the headlights of an oncoming vehicle, for example.

[0008] In recent years, the diversification of HUDs has created a demand for interlayer films with variable wedge angles. For example, if the wedge angle of the display-corresponding area of ​​the interlayer film that corresponds to the display area of ​​the HUD is large, the wedge angle of the area other than the display-corresponding area may be made smaller. By adjusting the wedge angle in this way, it is possible to prevent the wedge angle of the entire interlayer film from becoming too large. By preventing the wedge angle of the entire interlayer film from becoming too large, it is possible to prevent wrinkles from occurring in the interlayer film. In addition, when the interlayer film is rolled, it is less likely to become misaligned when wound.

[0009] However, in an interlayer film with an inconsistent wedge angle, there are likely to be positions where the wedge angle changes significantly. This makes it easy for transmitted double images to occur in the laminated glass. In particular, transmitted double images can occur in the laminated glass at positions where the wedge angle changes significantly.

[0010] An object of the present invention is to provide an interlayer film for laminated glass that can suppress transmitted double images in laminated glass. Another object of the present invention is to provide a roll body and laminated glass using the interlayer film for laminated glass. [Means for solving the problem]

[0011] According to a broad aspect of the present invention, there is provided an interlayer film for laminated glass (in this specification, "interlayer film for laminated glass" may be abbreviated to "interlayer film") that has one end and another end opposite to the one end, the thickness of the other end being greater than the thickness of the one end, and when the slope of the approximate straight line A and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the following formula for approximate straight line A and calculation of the deviation of the partial wedge angle, in at least one section A, the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less:

[0012] Calculation of the equation of approximation line A and the deviation of the partial wedge angle: Calculate the equation of approximation line A and the deviation of the partial wedge angle in the order of 1 to 4 below.

[0013] 1: A position 40 mm from the one end of the intermediate film toward the other end is defined as a start point X, and a position 40 mm from the other end of the intermediate film toward the one end is defined as an end point X. Points A are selected at 1 mm intervals from the start point X toward the end point X.

[0014] 2: Calculate the partial wedge angle A in each 80 mm partial area A in the direction connecting the one end and the other end with each point A as the center, to obtain the "partial wedge angle A at each point A."

[0015] 3: A position 190 mm from the one end of the intermediate film toward the other end is set as a start point Y, and a position 190 mm from the other end of the intermediate film toward the one end is set as an end point Y. 300 mm sections A are set at 1 mm intervals from the start point Y toward the end point Y so that the center of each section A is located between the start point Y and the end point Y.

[0016] 4: Determine the equation of the approximate straight line A below and the deviation of the partial wedge angle below.

[0017] Equation of approximate straight line A: In each of sections A, an approximation straight line is created from the "partial wedge angle A at each point A" where the point A exists within the section A, with the x-axis direction defined as the "distance from the one end of the interlayer film" and the y-axis direction defined as the "partial wedge angle A," and the equation of the approximation straight line A in each section A is determined.

[0018] Deviation of partial wedge angle: The partial wedge angle A' at each point A is calculated from the equation of the approximate straight line A to obtain the "partial wedge angle A' at each point A on the approximate straight line A." For each section A, the deviation of the partial wedge angle in each section A is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A' at each point A on the approximate straight line A" where the point A exists within the section A.

[0019] In a specific aspect of the interlayer film according to the present invention, in at least one section A included between a position 100 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film, the slope of the approximation line A is −0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

[0020] In a specific aspect of the interlayer film according to the present invention, in at least one section A included between a position 600 mm from the one end toward the other end of the interlayer film and the other end of the interlayer film, the slope of the approximate straight line A is −0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

[0021] In a specific aspect of the interlayer film according to the present invention, when the slope of approximate line B and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the following formula for approximate line B and calculation of the deviation of the partial wedge angle, in section B, the slope of approximate line B is −0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

[0022] Calculation of the equation of the approximate straight line B and the deviation of the partial wedge angle: Calculate the equation of the approximate straight line B and the deviation of the partial wedge angle in the order of 5 and 6 below.

[0023] 5: A section between a position 50 mm from the one end of the intermediate film toward the other end and a position 50 mm from the other end of the intermediate film toward the one end is set as section B.

[0024] 6: Determine the equation of the approximate straight line B below and the deviation of the partial wedge angle below.

[0025] Equation of approximate straight line B: In section B, from the "partial wedge angle A at each point A" where point A exists within section B, an approximate straight line B is created with the x-axis direction set to the "distance from the one end of the interlayer film" and the y-axis direction set to the "partial wedge angle A," and the equation of approximate straight line B in section B is found.

[0026] Deviation of partial wedge angle: The partial wedge angle A'' at each point A is calculated from the equation of the approximation line B to obtain the "partial wedge angle A'' at each point A on the approximation line B." In section B, the deviation of the partial wedge angle in section B is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A'' at each point A on the approximation line B" where the point A exists within the section B.

[0027] In a particular aspect of the interlayer film according to the present invention, at least one outer surface of the interlayer film is embossed.

[0028] In one particular aspect of the interlayer film according to the present invention, 50% or more of the area of ​​the embossed outer surface of the interlayer film has a ten-point mean roughness within ±30% of the average ten-point mean roughness of the entire embossed outer surface of the interlayer film.

[0029] In a specific aspect of the interlayer film according to the present invention, when the distance between the one end and the other end of the interlayer film is U, the absolute value of the difference between the maximum heat shrinkage rate and the minimum heat shrinkage rate among three heat shrinkage rates: a first heat shrinkage rate at 150°C in the MD direction at a first position 0.05U from the one end toward the other end, a second heat shrinkage rate at 150°C in the MD direction at a second position 0.5U from the one end toward the other end, and a third heat shrinkage rate at 150°C in the MD direction at a third position 0.95U from the one end toward the other end, is 15% or less.

[0030] In a specific aspect of the interlayer film according to the present invention, the maximum thickness of the interlayer film is 1700 μm or less.

[0031] According to a broad aspect of the present invention, there is provided a roll body including a winding core and the above-mentioned interlayer film for laminated glass, the interlayer film for laminated glass being wound around an outer periphery of the winding core.

[0032] According to a broad aspect of the present invention, there is provided laminated glass comprising a first laminated glass component, a second laminated glass component, and the above-mentioned interlayer film for laminated glass, with the interlayer film for laminated glass being disposed between the first laminated glass component and the second laminated glass component. Effect of the Invention

[0033] The interlayer film for laminated glass according to the present invention has one end and another end opposite to the one end, and the thickness of the other end is greater than the thickness of the one end. Based on the formula for the approximate line A and the calculation of the deviation of the partial wedge angle, the slope of the approximate line A and the maximum absolute value of the deviation of the partial wedge angle are calculated. When this calculation is performed, in at least one section A of the interlayer film for laminated glass according to the present invention, the slope of the approximate line A is -0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. Since the interlayer film for laminated glass according to the present invention has the above configuration, it is possible to suppress transmitted double images in the laminated glass. [Brief description of the drawings]

[0034] [Figure 1] 1(a) and 1(b) are a cross-sectional view and a front view that typically show an interlayer film for laminated glass according to a first embodiment of the present invention. [Diagram 2] 2(a) and (b) are a cross-sectional view and a front view that typically show an interlayer film for laminated glass according to a second embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates an interlayer film for laminated glass according to a third embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic diagram of an interlayer film for laminated glass according to a fourth embodiment of the present invention. [Diagram 5]FIG. 5 is a cross-sectional view showing an example of laminated glass using the interlayer film for laminated glass shown in FIG. [Figure 6] FIG. 6 is a perspective view that illustrates a roll around which the interlayer film for laminated glass shown in FIG. 1 is wound. [Figure 7] FIG. 7 is a diagram illustrating an interlayer film (test piece) for measuring the thermal shrinkage rate. [Figure 8] FIG. 8 is a diagram for explaining a pre-press method in the evaluation of reflective double images and transmitted double images in the examples. [Figure 9] FIG. 9 is a schematic diagram showing the relationship between the distance from one end of the interlayer film in section B of FIG. 3 and the partial wedge angle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The present invention will be described in detail below.

[0036] The interlayer film for laminated glass according to the present invention (sometimes abbreviated as "interlayer film" in this specification) is used for laminated glass.

[0037] The interlayer film according to the present invention has a one-layer structure or a two or more layer structure. The interlayer film according to the present invention may have a one-layer structure, or a two or more layer structure. The interlayer film according to the present invention may have a two-layer structure, a three-layer structure, or a three or more layer structure. The interlayer film according to the present invention may be a single-layer interlayer film, or a multi-layer interlayer film.

[0038] The interlayer film according to the present invention has one end and another end opposite the one end. The one end and the other end are opposite ends of the interlayer film. In the interlayer film according to the present invention, the thickness of the other end is greater than the thickness of the one end.

[0039] In the interlayer film according to the present invention, the following formula for approximate straight line A and the deviation of the partial wedge angle are calculated.

[0040] Calculation of the equation of approximation line A and the deviation of the partial wedge angle: Calculate the equation of approximation line A and the deviation of the partial wedge angle in the order of 1 to 4 below.

[0041] 1: A position 40 mm from the one end of the interlayer film toward the other end is defined as a start point X, and a position 40 mm from the other end of the interlayer film toward the one end is defined as an end point X. Points A are selected at 1 mm intervals from the start point X toward the end point X.

[0042] 2: Calculate the partial wedge angle A in each 80 mm partial area A in the direction connecting the one end and the other end with each point A as the center, to obtain the "partial wedge angle A at each point A."

[0043] 3: A position 190 mm from the one end of the intermediate film toward the other end is set as a start point Y, and a position 190 mm from the other end of the intermediate film toward the one end is set as an end point Y. 300 mm sections A are set at 1 mm intervals from the start point Y toward the end point Y so that the center of each section A is located between the start point Y and the end point Y.

[0044] 4: Determine the equation of the approximate straight line A below and the deviation of the partial wedge angle below.

[0045] Equation of approximate straight line A: In each of sections A, from the "partial wedge angle A at each point A" where the point A exists within that section A, an approximate straight line A is created with the x-axis direction set to the "distance from the one end of the interlayer film" and the y-axis direction set to the "partial wedge angle A," and the equation of approximate straight line A in each section A is obtained.

[0046] Deviation of partial wedge angle: The partial wedge angle A' at each point A is calculated from the equation of the approximate straight line A to obtain the "partial wedge angle A' at each point A on the approximate straight line A." For each section A, the deviation of the partial wedge angle in each section A is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A' at each point A on the approximate straight line A" where the point A exists within that section A.

[0047] In 1 above, each point A is set with a 1 mm shift. Points are selected up to a position where points can be selected at 1 mm intervals from one end to the other end of the interlayer film (positions where the intervals are not less than 1 mm). The point A closest to the one end of the interlayer film is point A1, which is 40 mm from the one end of the interlayer film towards the other end, and the next point A is point A2, which is 41 mm from the one end of the interlayer film towards the other end. Point An is located (39+n) mm (n is a natural number) from the one end of the interlayer film towards the other end.

[0048] In the above 2:, the partial region A closest to the one end of the intermediate film is partial region A1, which is 0 mm to 80 mm from the one end, and the next partial region A is partial region A2, which is 1 mm to 81 mm from the one end. Partial region An is a partial region that is (n-1) mm to (79+n) mm (n is a natural number) from the one end. Two adjacent partial regions A overlap each other by 79 mm in the direction connecting the one end and the other end.

[0049] In the above 2:, a partial region A is set for each point A. The partial wedge angle calculated in each partial region A is referred to as the partial wedge angle A. This partial wedge angle A is referred to as the "partial wedge angle A at each point A." In the partial region A1 at the point A1 closest to the one end of the interlayer film, the partial wedge angle A1 at the point A1 is calculated, and in the partial region A2 at the next point A2, the partial wedge angle A2 at the point A2 is calculated. The partial wedge angle A in the region closest to the one end of the interlayer film is the partial wedge angle in the region 0 mm to 80 mm from the one end of the interlayer film (partial wedge angle A1 in partial region A1), and the next partial wedge angle A is the partial wedge angle in the region 1 mm to 81 mm from the one end of the interlayer film (partial wedge angle A2 in partial region A2).

[0050] Specifically, the partial wedge angle A is measured as follows.

[0051] Measurement points P are selected at 1 mm intervals, with one end of partial area A as start point Z and the other end of partial area A as end point Z. Therefore, 81 measurement points P are selected in one partial area A. The thickness of the interlayer film is measured at each measurement point P. An approximation line is obtained by the least squares method, with the x-axis direction being the distance from one end of the interlayer film (unit: mm) and the y-axis direction being the thickness of the interlayer film (unit: mm). The interior angle between the obtained approximation line and the line y = 0 is defined as the partial wedge angle A.

[0052] In the above 3:, from the start point Y (a position 190 mm from one end of the intermediate film toward the other end) to the end point Y (a position 190 mm from the other end of the intermediate film toward one end), sections A are set up to a position where a section of 300 mm can be set at 1 mm intervals (a position where the section is not less than 300 mm) so that the center of each section A is located between the start point Y and the end point Y.

[0053] In the above 3:, each section A is set with a shift of 1 mm. The section A closest to the one end of the interlayer film is section A1, which is 40 mm to 340 mm from the one end of the interlayer film, and the next section A is section A2, which is 41 mm to 341 mm from the one end of the interlayer film. Section An is a section from (n-1) mm to (299+n) mm (n is a natural number) from the starting point. Each section An is a partial region from (39+n) mm to (339+n) mm (n is a natural number) from the one end of the interlayer film. Two adjacent sections A overlap each other by 299 mm in the direction connecting the one end and the other end. There are 301 points A in one section A.

[0054] In 4: above, for each section A, the equation of the approximate line and the deviation of the partial wedge angle are calculated from the "partial wedge angle A at each point A" where the point A (the point A centered in 2: above) exists in that section A.

[0055] In the first section A (the above section A1), partial wedge angles A1 to A301 exist, and in the next section A (the above section A2), partial wedge angles A2 to A302 exist. In one section A, there are 301 partial wedge angles A.

[0056] Specifically, the equation of the approximate straight line A is determined as follows.

[0057] In each of the sections A, an approximate straight line A is created for the 301 partial wedge angles A. The x-axis direction is defined as the "distance from the one end of the interlayer film (unit: m)" and the y-axis direction is defined as the "partial wedge angle A (unit: mrad)", and the approximate straight line A is obtained by the least squares method. The "distance from the one end of the interlayer film" in the x-axis direction of the partial wedge angle A is defined as the distance between the one end of the interlayer film and the point A that is the center in 2: above. The x-coordinate of the partial wedge angle A1 is x = 0.040 m (40 mm). The x-coordinate of the partial wedge angle A2 is x = 0.041 m (41 mm). The distance in the x-axis direction in one section A is 0.300 m (300 mm). The equation of one approximate straight line A is obtained in one section A.

[0058] Specifically, the deviation of the partial wedge angle is measured as follows.

[0059] From the equation of the approximate straight line A above, the partial wedge angle A' at each point A is calculated to obtain the "partial wedge angle A' at each point A on the approximate straight line A." Therefore, 301 partial wedge angles A' are obtained in each section A. In each section A, the partial wedge angle deviations are calculated from the 301 partial wedge angles A and the 301 partial wedge angles A'. In one section A, the deviations of 301 partial wedge angles are obtained.

[0060] In the interlayer film according to the present invention, when the slope of the approximate straight line A and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the formula for the approximate straight line A and the calculation of the deviation of the partial wedge angle, in at least one section A, the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. In the interlayer film according to the present invention, there is a section A (a section of 300 mm) that satisfies the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less". There may be one or more sections A that satisfy the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less". From the viewpoint of more effectively suppressing transmitted double images, it is preferable that there are multiple sections A that satisfy the configuration in which "the gradient of the approximate straight line A is -0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less."

[0061] The interlayer film of the present invention has the above configuration, and is therefore able to suppress transmitted double images in laminated glass. The interlayer film of the present invention can suppress transmitted double images in laminated glass in a region where the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. The interlayer film of the present invention has the above configuration, and is able to suppress reflected double images in laminated glass. The interlayer film of the present invention can suppress reflected double images in laminated glass in a region where the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

[0062] The transmitted double image is, for example, a phenomenon in which a double image is observed due to illumination by the headlights of an oncoming vehicle.

[0063] The reflected double image is a phenomenon in which a double image is observed due to, for example, information being irradiated from an information display device.

[0064] In at least one section A included between a position 100 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. It is preferable that a section A satisfying the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less" exists between a position 100 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and reflected double images can be suppressed even more effectively.

[0065] Whether or not section A exists at any position of the interlayer film is determined based on whether or not the entire 300 mm section A exists at the any position. Whether or not section A exists between a position 100 mm from the one end of the interlayer film toward the other end and a position 600 mm from the one end of the interlayer film toward the other end is determined based on whether or not the entire 300 mm section A exists between a position 100 mm from the one end of the interlayer film toward the other end and a position 600 mm from the one end of the interlayer film toward the other end.

[0066] In all sections A between a position 100 mm from one end of the interlayer film toward the other end and a position 600 mm from one end of the interlayer film toward the other end, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and reflected double images in particular can be suppressed even more effectively.

[0067] In at least one section A included between a position 100 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film, the maximum absolute value of the deviation of the partial wedge angle is preferably 0.2 mrad or less. The maximum absolute value of the deviation of the partial wedge angle is more preferably 0.17 mrad or less, even more preferably 0.15 mrad or less, even more preferably 0.14 mrad or less, even more preferably 0.13 mrad or less, and particularly preferably 0.10 mrad or less. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and reflected double images can be suppressed even more effectively.

[0068] In at least one section A included between a position 200 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. It is preferable that a section A satisfying the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less" exists between a position 200 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film. In this case, transmitted double images and reflected double images can be suppressed more effectively, and in particular, reflected double images can be suppressed more effectively.

[0069] In all sections A between a position 200 mm from one end of the interlayer toward the other end and a position 500 mm from one end of the interlayer toward the other end, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and reflected double images in particular can be suppressed even more effectively.

[0070] In at least one section A included between a position 600 mm from one end of the interlayer film toward the other end and the other end of the interlayer film, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. It is preferable that a section A satisfying the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less" exists between a position 600 mm from one end of the interlayer film toward the other end and the other end of the interlayer film. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and transmitted double images can be suppressed even more effectively in particular.

[0071] It is preferable that in all sections A included between a position 600 mm from one end toward the other end of the interlayer film and the other end of the interlayer film, the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and transmitted double images can be suppressed even more effectively.

[0072] In at least one section A included between a position 600 mm from one end of the interlayer film toward the other end and the other end of the interlayer film, the maximum absolute value of the deviation of the partial wedge angle is preferably 0.2 mrad or less. The maximum absolute value of the deviation of the partial wedge angle is more preferably 0.17 mrad or less, even more preferably 0.15 mrad or less, even more preferably 0.14 mrad or less, and even more preferably 0.13 mrad or less. When the maximum absolute value of the deviation of the partial wedge angle in at least one section A included between a position 600 mm from one end of the interlayer film toward the other end and the other end of the interlayer film is equal to or less than the upper limit, reflected double images and transmitted double images can be suppressed even more effectively, and in particular transmitted double images can be suppressed even more effectively.

[0073] In at least one section A included between a position 700 mm from one end of the interlayer film toward the other end and the other end of the interlayer film, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. It is preferable that a section A satisfying the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less" exists between a position 700 mm from one end of the interlayer film toward the other end and the other end of the interlayer film. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and transmitted double images can be suppressed even more effectively in particular.

[0074] In all sections A between a position 700 mm from one end of the interlayer film toward the other end and the other end of the interlayer film, it is preferable that the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. It is preferable that a section A satisfying the configuration that "the slope of the approximate straight line A is -0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less" exists between a position 700 mm from one end of the interlayer film toward the other end and the other end of the interlayer film. In this case, transmitted double images and reflected double images can be suppressed even more effectively, and transmitted double images can be suppressed even more effectively in particular.

[0075] In the interlayer film according to the present invention, the following formula for the approximate straight line B and the deviation of the partial wedge angle are calculated.

[0076] Calculation of the equation of approximate straight line B and the deviation of the partial wedge angle: Calculate the equation of approximate straight line B and the deviation of the partial wedge angle in the following order of 5 and 6. More specifically, the equation of approximate straight line B and the deviation of the partial wedge angle are calculated in the above order of 1 and 2 and the following order of 5 and 6.

[0077] 5: The section between a position 50 mm from the one end of the intermediate film toward the other end and a position 50 mm from the other end of the intermediate film toward the one end is set as section B.

[0078] 6: Determine the equation of the approximate straight line B below and the deviation of the partial wedge angle below.

[0079] Equation of approximate straight line B: In section B, from the "partial wedge angle A at each point A" where the above-mentioned point A exists within section B, an approximate straight line B is created with the x-axis direction set to the "distance from the above-mentioned one end of the interlayer film" and the y-axis direction set to the "partial wedge angle A," and the equation of approximate straight line B in section B is found.

[0080] Deviation of partial wedge angle: The partial wedge angle A'' at each point A is calculated from the equation of the approximate straight line B to obtain the "partial wedge angle A'' at each point A on the approximate straight line B." In section B, the deviation of the partial wedge angle in section B is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A'' at each point A on the approximate straight line B" where the point A exists within the section B.

[0081] Specifically, the equation of the approximate line B is determined as follows.

[0082] In section B, an approximation line B is created for partial wedge angle A. The number of partial wedge angles B varies depending on the size of the interlayer film. The x-axis direction is defined as the "distance from the one end of the interlayer film (unit: m)" and the y-axis direction is defined as the "partial wedge angle A (unit: mrad)", and the approximation line B is obtained by the least squares method. The "distance from the one end of the interlayer film" of partial wedge angle A in the x-axis direction is defined as the distance between the one end of the interlayer film and point A that is the center in 2: above. The x-coordinate of partial wedge angle A1 is x = 0.040 m (40 mm). The x-coordinate of partial wedge angle A2 is x = 0.041 m (41 mm). The distance in the x-axis direction in section B varies depending on the size of the interlayer film. In section B, the equation of one approximation line B is obtained.

[0083] Specifically, the deviation of the partial wedge angle is measured as follows.

[0084] From the equation of the above approximate line B, the partial wedge angle A'' at each point A is calculated to obtain the "partial wedge angle A'' at each point A on the approximate line B." In section B, the deviation of the partial wedge angle is calculated from each partial wedge angle A and each partial wedge angle A''.

[0085] In the interlayer film according to the present invention, when the slope of the approximate line B and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the formula for the approximate line B and the calculation of the deviation of the partial wedge angle, it is preferable that the slope of the approximate line B is −0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less in section B. In this case, it is possible to simultaneously suppress transmitted double images and reflected double images in the laminated glass.

[0086] The gradients of the approximate straight lines A and B are preferably -3 mrad / m or more, more preferably -2 mrad / m or more, preferably -0.07 mrad / m or less, and more preferably -0.10 mrad / m or less. When the gradients of the approximate straight lines A and B are equal to or more than the lower limit and equal to or less than the upper limit, transmitted double images and reflected double images can be more effectively suppressed.

[0087] The intercepts of the approximate straight lines A and B are preferably 0.05 mrad or more, more preferably 0.1 mrad or more, preferably 3 mrad or less, and more preferably 2 mrad or less. When the intercepts of the approximate straight lines A and B are equal to or more than the lower limit and equal to or less than the upper limit, transmitted double images and reflected double images can be suppressed more effectively.

[0088] The maximum absolute value of the deviation of the partial wedge angle is preferably 0.2 mrad or less, more preferably 0.17 mrad or less, even more preferably 0.15 mrad or less, particularly preferably 0.14 mrad or less, and most preferably 0.13 mrad or less. When the maximum absolute value of the deviation of the partial wedge angle is equal to or less than the upper limit, transmitted double images and reflected double images can be suppressed more effectively. The smaller the maximum value of the deviation of the partial wedge angle, the more preferable it is.

[0089] Methods for controlling the slope and intercept of the approximate straight lines A and B and the maximum absolute value of the deviation of the partial wedge angle within the above preferred ranges include the following: (1) Adjusting the gap at the die outlet. (2) Adjusting the degree of mixing of the resin composition in the melting section of the extruder. (3) Adjusting the temperature of the resin composition at the extrusion outlet. By appropriately combining these methods, it is possible to control the slope and intercept of the approximate straight lines A and B and the maximum absolute value of the deviation of the partial wedge angle within the above preferred ranges.

[0090] It is preferable that the thickness of the intermediate film increases from one end to the other end in 80% or more (more preferably 85% or more, even more preferably 90% or more, and particularly preferably 95% or more) of the region from a position 10 cm from the one end toward the other end to a position 60 cm from the one end toward the other end. In this case, reflected double images can be suppressed even more effectively.

[0091] The interlayer film according to the present invention is suitably used for laminated glass for a head-up display (HUD). The interlayer film according to the present invention is preferably an interlayer film for a HUD.

[0092] The interlayer film of the present invention preferably has a display corresponding area corresponding to the display area of ​​the HUD. From the viewpoint of more effectively suppressing transmitted double images and reflected double images, the interlayer film of the present invention preferably has the display corresponding area within a region extending from a position 10 cm from the one end toward the other end to a position 60 cm from the one end toward the other end.

[0093] From the viewpoint of effectively suppressing transmitted double images and reflected double images, it is preferable that the intermediate film has a portion having a wedge-shaped cross section in the thickness direction in a region from a position 60 cm from the one end toward the other end to a position 10 cm from the other end toward the one end. The portion having a wedge-shaped cross section in the thickness direction may be present in at least a part of the region.

[0094] The interlayer film according to the present invention may have a shade area. The shade area may be separated from the display corresponding area. The shade area is provided for the purpose of preventing the driver from feeling glare due to, for example, sunlight or outdoor lighting while driving. The shade area may be provided to provide heat insulation. The shade area is preferably located at the edge of the interlayer film. The shade area is preferably in the form of a strip.

[0095] In the shade region, a colorant or filler may be used to change the color and visible light transmittance, etc. The colorant or filler may be contained in only a part of the region in the thickness direction of the interlayer film, or may be contained in the entire region in the thickness direction of the interlayer film.

[0096] From the viewpoint of improving the display and widening the field of view, the visible light transmittance of the display corresponding area is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, particularly preferably 88% or more, and most preferably 90% or more. The visible light transmittance of the display corresponding area is preferably higher than that of the shade area. The visible light transmittance of the display corresponding area may be lower than that of the shade area. The visible light transmittance of the display corresponding area is preferably 50% or more higher, more preferably 60% or more higher than that of the shade area.

[0097] For example, when the visible light transmittance varies in the interlayer film in the display corresponding area and the shade area, the visible light transmittance is measured at the center position of the display corresponding area and the center position of the shade area.

[0098] The visible light transmittance of the obtained laminated glass at wavelengths of 380 nm to 780 nm can be measured using a spectrophotometer (Hitachi High-Technologies Corporation's "U-4100") in accordance with JIS R3211: 1998. It is preferable to use clear glass with a thickness of 2 mm as the glass plate.

[0099] The display corresponding region preferably has a length direction and a width direction. Since the interlayer film has excellent versatility, the width direction of the display corresponding region is preferably a direction connecting the one end and the other end. The display corresponding region is preferably strip-shaped.

[0100] The interlayer film 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 production. The TD direction is a direction perpendicular to the flow direction of the interlayer film during production and perpendicular to the thickness direction of the interlayer film. The one end and the other end are preferably located on both sides of the TD direction.

[0101] From the viewpoint of improving the display, it is preferable that the interlayer film has a portion whose cross section in the thickness direction is wedge-shaped. It is preferable that the cross section in the thickness direction of the display corresponding region is wedge-shaped.

[0102] The interlayer film preferably has a portion having a wedge-shaped cross section in the thickness direction. The interlayer film preferably has a portion whose thickness gradually increases from one end to the other end. The interlayer film preferably has a wedge-shaped cross section in the thickness direction. Examples of the cross section of the interlayer film in the thickness direction include a trapezoid, a triangle, and a pentagon.

[0103] From the viewpoint of further suppressing ghost images, it is preferable that the interlayer film has a portion in which the amount of increase in thickness increases from one end side to the other end side in the region where the thickness increases. From the viewpoint of further suppressing ghost images, it is preferable that the interlayer film has a portion in which the wedge angle increases from one end side to the other end side in the region where the cross-sectional shape in the thickness direction is wedge-shaped.

[0104] In order to suppress double images, the wedge angle (θ) of the interlayer film can be appropriately set according to the installation angle of the laminated glass. The wedge angle (θ) is the wedge angle of the entire interlayer film. From the viewpoint of further suppressing double images, the wedge angle (θ) of the interlayer film is preferably 0.1 mrad (0.00575 degrees) or more, more preferably 0.2 mrad (0.0115 degrees) or more, and preferably 2 mrad (0.1146 degrees) or less, more preferably 0.8 mrad (0.0458 degrees) or less. The wedge angle (θ) of the interlayer film is the interior angle at the intersection of a straight line connecting the surface portion (first surface portion) on one side of the interlayer film between the maximum thickness portion and the minimum thickness portion of the interlayer film and a straight line connecting the surface portion (second surface portion) on the other side of the interlayer film between the maximum thickness portion and the minimum thickness portion of the interlayer film.

[0105] In addition, when there are multiple maximum thickness parts, multiple minimum thickness parts, the maximum thickness part is in a fixed region, or the minimum thickness part is in a fixed region, the maximum thickness part and the minimum thickness part for determining the wedge angle (θ) are selected so that the determined wedge angle (θ) is largest.

[0106] The wedge angle (θ) can be approximately calculated as follows: The thickness of the interlayer film is measured at each of the maximum thickness portion and the minimum thickness portion. The wedge angle (θ) is approximately calculated based on the result (the absolute value (μm) of the difference between the thickness at the maximum thickness portion and the thickness at the minimum thickness portion ÷ the distance (mm) from the maximum thickness portion to the minimum thickness portion).

[0107] Generally, the larger the wedge angle (θ) of the interlayer film, the more likely it is that transmitted double images will occur through the laminated glass. In the present invention, even if the wedge angle (θ) of the interlayer film is large, transmitted double images through the laminated glass can be made less likely to occur.

[0108] The thickness of the interlayer film is not particularly limited. The thickness of the interlayer film indicates the total thickness of each layer constituting the interlayer film. Therefore, in the case of a multi-layer interlayer film having a first layer, a second layer, and a third layer, the thickness of the interlayer film indicates the total thickness of the first layer, the second layer, and the third layer.

[0109] The distance between one end and the other end is U. The interlayer preferably has a minimum thickness in a region of 0U to 0.2U from one end toward the inside, and a maximum thickness in a region of 0U to 0.2U from the other end toward the inside. It is more preferable that the interlayer has a minimum thickness in a region of 0U to 0.1U from one end toward the inside, and a maximum thickness in a region of 0U to 0.1U from the other end toward the inside. It is preferable that the interlayer has a minimum thickness at one end, and a maximum thickness at the other end.

[0110] The maximum thickness of the interlayer is preferably 100 μm or more, more preferably 250 μm or more, even more preferably 500 μm or more, particularly preferably 800 μm or more, and is preferably 3 mm or less, more preferably 2 mm or less, even more preferably 1700 μm or less, particularly preferably 1500 μm or less.

[0111] From the viewpoint of practical use and from the viewpoint of sufficiently increasing adhesive strength and penetration 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, and is preferably 1 mm or less, more preferably 0.8 mm or less.

[0112] From the viewpoint of practical use and from the viewpoint of sufficiently increasing penetration resistance, the maximum thickness of the layer (intermediate layer) disposed 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, and is preferably 0.8 mm or less, more preferably 0.6 mm or less, even more preferably 0.3 mm or less.

[0113] The distance U between one end and the other end of the interlayer is preferably 0.5 m or more, more preferably 0.8 m or more, particularly preferably 1 m or more, and is preferably 3 m or less, more preferably 2 m or less, particularly preferably 1.5 m or less.

[0114] The measuring device used to measure the wedge angle and thickness of the interlayer film may be a contact type thickness measuring device "TOF-4R" (manufactured by Yamabun Denki Co., Ltd.).

[0115] The thickness is measured using the above-mentioned measuring device at a membrane transport speed of 2.15 mm / min to 2.25 mm / min over the shortest distance from one end to the other end.

[0116] An appropriate measuring device is used to measure the wedge angle (θ) of the interlayer film after it is made into laminated glass and the thickness of the interlayer film. Examples of such measuring devices include the non-contact multilayer film thickness measuring device "OPTIGAUGE" (manufactured by Lumetrics). Using this measuring device, the thickness of the interlayer film can be measured in the form of laminated glass.

[0117] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0118] 1(a) and (b) are a cross-sectional view and a front view showing a schematic diagram of an interlayer film for laminated glass according to a first embodiment of the present invention. Fig. 1(a) is a cross-sectional view taken along line II in Fig. 1(b). Note that the size and dimensions of the interlayer film in Fig. 1 and the figures described below have been appropriately changed from the actual size and shape for the convenience of illustration.

[0119] Fig. 1(a) shows a cross section in the thickness direction of the interlayer film 11. Note that, for convenience of illustration, in Fig. 1(a) and the figures described below, the thickness and wedge angle (θ) of the interlayer film and each layer constituting the interlayer film are shown to be different from the actual thickness and wedge angle.

[0120] The interlayer film 11 includes a first layer 1 (interlayer), a second layer 2 (surface layer), and a third layer 3 (surface layer). The second layer 2 is disposed on a first surface side of the first layer 1 and laminated therewith. The third layer 3 is disposed on a second surface side opposite to the first surface of the first layer 1 and laminated therewith. The first layer 1 is disposed and sandwiched between the second layer 2 and the third layer 3. The interlayer film 11 is used to obtain laminated glass. The interlayer film 11 is an interlayer film for laminated glass. The interlayer film 11 is a multilayer interlayer film.

[0121] The intermediate film 11 has one end 11a and the other end 11b opposite the one end 11a. The one end 11a and the other end 11b are end portions on both sides facing each other. 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 second layer 2 and the third layer 3 are thicker on the other end 11b side than on the one end 11a side. Therefore, the thickness of the other end 11b of the intermediate film 11 is thicker than the thickness of the one end 11a. Therefore, the intermediate film 11 has a thin region and a thick region.

[0122] The intermediate film 11 has a region where the thickness increases from one end 11a to the other end 11b. In the region where the thickness increases, the amount of increase in thickness of the intermediate film 11 is not uniform from one end 11a to the other end 11b.

[0123] The intermediate film 11 has a region where the thickness increases from one end 11a to the other end 11b. In the region where the thickness increases, the intermediate film 11 has a portion where the increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11 also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. In the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11 has a portion where the wedge angle decreases from one end to the other end.

[0124] The intermediate film 11 has a display corresponding region R1 corresponding to the display region of the head-up display. The intermediate film 11 has a surrounding region R2 adjacent to the display corresponding region R1. In this embodiment, the display corresponding region R1 is a 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.

[0125] The intermediate film 11 has a shade region R3 located at the edge of the intermediate film 11 and separated from the display corresponding region R1.

[0126] The intermediate film may be a single layer, two layers, or four or more layers in the shape shown in FIG. 1(a).

[0127] FIG. 6 is a perspective view that illustrates a roll around which the interlayer film for laminated glass shown in FIG. 1 is wound.

[0128] The interlayer film 11 may be wound into a roll 51 of the interlayer film 11 .

[0129] 6 includes a winding core 61 and an intermediate film 11. The intermediate film 11 is wound around the outer periphery of the winding core 61.

[0130] 2(a) and (b) are a cross-sectional view and a front view showing a schematic diagram of an interlayer film for laminated glass according to a second embodiment of the present invention. Fig. 2(a) is a cross-sectional view taken along line II in Fig. 2(b). Fig. 2(a) shows a cross section in the thickness direction of an interlayer film 11A.

[0131] The interlayer film 11A shown in FIG. 2 includes a first layer 1A. The interlayer film 11A has a single-layer structure including only the first layer 1A, and is a single-layer interlayer film. The interlayer film 11A is the first layer 1A. The interlayer film 11A is used to obtain laminated glass. The interlayer film 11A is an interlayer film for laminated glass.

[0132] The intermediate film 11A has one end 11a and the other end 11b opposite the one end 11a. The one end 11a and the other end 11b are opposite ends of each other. The thickness of the other end 11b of the intermediate film 11A is greater than the thickness of the one end 11a. Thus, the intermediate film 11A and the first layer 1A have a thin region and a thick region.

[0133] The intermediate film 11A has a region where the thickness increases from one end 11a to the other end 11b. In the region where the thickness increases, the amount of increase in thickness is not uniform from one end 11a to the other end 11b.

[0134] The intermediate film 11A has a region where the thickness increases from one end 11a to the other end 11b. In the region where the thickness increases, the intermediate film 11A has a portion where the increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11A also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. In the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11A has a portion where the wedge angle decreases from one end to the other end.

[0135] The intermediate film 11A and the first layer 1A have portions 11Aa, 1Aa whose cross-sectional shape in the thickness direction is rectangular, and portions 11Ab, 1Ab whose cross-sectional shape in the thickness direction is wedge-shaped.

[0136] The intermediate film 11A has a display corresponding region R1 corresponding to the display region of the head-up display. The intermediate film 11A has a surrounding region R2 adjacent to the display corresponding region R1.

[0137] The intermediate film 11A has a shade region R3 located at the edge of the intermediate film 11A and separated from the display corresponding region R1.

[0138] The intermediate film may be two or more layers in the shape shown in FIG. 2(a).

[0139] 3 is a cross-sectional view that illustrates an interlayer film for laminated glass according to a third embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11B.

[0140] The intermediate film 11B shown in FIG. 3 includes a first layer 1B (intermediate layer), a second layer 2B (surface layer), and a third layer 3B (surface layer).

[0141] The intermediate film 11B has a region where the thickness increases from one end 11a to the other end 11b, and a region where the thickness decreases from one end 11a to the other end 11b. In the region where the thickness increases, the intermediate film 11B has a portion where the increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11B also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. In the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11B has a portion where the wedge angle decreases from one end to the other end.

[0142] Fig. 9 is a schematic diagram showing the relationship between the distance from one end of the interlayer film and the partial wedge angle in section B of the interlayer film in Fig. 3. Fig. 9 shows an approximate straight line B, partial wedge angle A at a certain point A, and partial wedge angle A''.

[0143] 4 is a cross-sectional view that illustrates an interlayer film for laminated glass according to a fourth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11C.

[0144] The intermediate film 11C shown in Fig. 4 includes a first layer 1C. The intermediate film 11C has a structure of only the first layer 1C, and is a single-layer intermediate film.

[0145] The intermediate film 11C has a region where the thickness increases from one end 11a to the other end 11b, and a region where the thickness decreases from one end 11a to the other end 11b. In the region where the thickness increases, the intermediate film 11C has a portion where the increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11C also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. In the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11C has a portion where the wedge angle decreases from one end to the other end.

[0146] The intermediate films 11 and 11A have a maximum thickness at the other end 11b and a minimum thickness at the one end 11a. The intermediate films 11B and 11C have a maximum thickness between the one end 11a and the other end 11b and a minimum thickness at the one end 11a.

[0147] The distance between the one end and the other end of the interlayer film is U. The following three heat shrinkage rates are obtained for the interlayer film. A first heat shrinkage rate at 150°C in the MD direction at a first position of 0.05U from the one end toward the other end. A second heat shrinkage rate at 150°C in the MD direction at a second position of 0.5U from the one end toward the other end. A third heat shrinkage rate at 150°C in the MD direction at a third position of 0.95U from the one end toward the other end. For the interlayer film, it is preferable that the absolute value of the difference between the maximum heat shrinkage rate and the minimum heat shrinkage rate among the three heat shrinkage rates of the first heat shrinkage rate, the second heat shrinkage rate, and the third heat shrinkage rate is 15% or less. In this case, the occurrence of wrinkles in the interlayer film can be effectively suppressed, and transmitted double images and reflected double images can be suppressed.

[0148] From the viewpoint of more effectively suppressing the occurrence of wrinkles in the interlayer film and from the viewpoint of more effectively suppressing transmitted double images and reflective double images, the maximum heat shrinkage rate of the above three heat shrinkage rates is preferably 50% or less, more preferably 48% or less, even more preferably 46% or less, and particularly preferably 45% or less. Of the above three heat shrinkage rates, the maximum heat shrinkage rate is not particularly limited. Of the above three heat shrinkage rates, the maximum heat shrinkage rate is preferably more than 20%, more preferably 22% or more, and even more preferably 24% or more.

[0149] From the viewpoint of more effectively suppressing the occurrence of wrinkles in the interlayer film, the absolute value of the difference between the maximum heat shrinkage rate and the minimum heat shrinkage rate among the three heat shrinkage rates is preferably 13% or less, more preferably 11% or less, and even more preferably 10% or less. There is no particular lower limit to the absolute value of the difference between the maximum heat shrinkage rate and the minimum heat shrinkage rate. The absolute value of the difference between the maximum heat shrinkage rate and the minimum heat shrinkage rate may be 0%.

[0150] The heat shrinkage rate is measured as follows.

[0151] FIG. 7 is a diagram illustrating an interlayer film (test piece) for measuring the thermal shrinkage rate.

[0152] In FIG. 7, one end and the other end of the interlayer film are located on both sides in the TD direction. The distance between the one end and the other end is U. The obtained interlayer film is cut out in a dimension of 10 cm in the MD direction from one end to the other end in the TD direction. After cutting, the cut interlayer film is conditioned for 2 days at a temperature of 20° C. and a humidity of 30% RH for stabilization. Then, as shown in FIG. 7, test pieces are cut out at a first position of 0.05 U from one end to the other end, a second position of 0.5 U from one end to the other end, and a third position of 0.95 U from one end to the other end. The test piece is a square of 5 cm in the MD direction and 5 cm in the TD direction. The test piece is cut out at the center of the test piece in the MD direction. The test piece is cut out so that the first position, the second position, and the third position are in the center. However, if the first position is not 2.5 cm or more away from one end, the test piece is cut out so that one end becomes one side of the test piece. If the third position is not more than 2.5 cm away from the other end, the test piece is cut out so that the other end becomes one side of the test piece.

[0153] The obtained test piece is placed horizontally on a fluororesin sheet and left for 0.5 hours at 150° C. The dimensions in the MD direction are measured before and after leaving it, and the thermal shrinkage is calculated using the following formula.

[0154] The thermal shrinkage rate in the MD direction of one test piece is measured at three points, namely, both end points and the center in the TD direction of one test piece (three points in the thick line area in Figure 7). The average value of the three measured values ​​is regarded as the thermal shrinkage rate in the MD direction of one test piece.

[0155] Heat shrinkage rate (%) = ((dimension in MD direction before heating - dimension in MD direction after heating) / dimension in MD direction before heating) x 100

[0156] Methods for controlling the maximum heat shrinkage and the absolute value of the difference between the maximum heat shrinkage and the minimum heat shrinkage to the above-mentioned preferred ranges include the following: (1) A method of reducing the difference between the maximum and minimum thicknesses of the interlayer film. (2) A method of maintaining the extruded interlayer film within a certain temperature range for a certain period of time when obtaining the interlayer film by melt extrusion molding. (3) A method of winding up the interlayer film with uniform tension over the entire TD direction when producing the interlayer film. By appropriately combining these methods, the maximum heat shrinkage and the absolute value of the difference between the maximum heat shrinkage and the minimum heat shrinkage can be controlled to the above-mentioned preferred ranges.

[0157] The intermediate film preferably has an uneven shape on its outer surface. In this case, it is sufficient that the intermediate film has an uneven shape on at least one of its two outer surfaces. The intermediate film preferably has an uneven shape on at least one of its two outer surfaces. It is more preferable that the intermediate film has an uneven shape on its two outer surfaces. It is preferable that at least one outer surface of the intermediate film is embossed. It is preferable that at least one outer surface of the intermediate film is embossed. It is preferable that at least one outer surface of the intermediate film is embossed. It is preferable that the outer surfaces of both sides of the intermediate film are embossed.

[0158] The method for forming the above uneven shape is not particularly limited, and examples thereof include a lip embossing method, an embossing roll method, a calendar roll method, a profile extrusion method, etc. The embossing roll method is preferred because it is capable of forming a large number of uneven embossments that are quantitatively uniform uneven patterns.

[0159] It is preferable that 50% or more of the embossed outer surface of the interlayer has a ten-point mean roughness within ±30% of the average ten-point mean roughness of the entire embossed outer surface of the interlayer, and more preferably has a ten-point mean roughness within ±25% of the average. It is more preferable that 60% or more of the embossed outer surface of the interlayer has a ten-point mean roughness within ±30% of the average ten-point mean roughness of the entire embossed outer surface of the interlayer. It is even more preferable that 70% or more of the embossed outer surface of the interlayer has a ten-point mean roughness within ±30% of the average ten-point mean roughness of the entire embossed outer surface of the interlayer. In this case, blocking between the films in the roll body can be effectively prevented.

[0160] The average ten-point height of the embossed outer surface of the interlayer is preferably 15 μm or more, more preferably 25 μm or more, and preferably 60 μm or less, and more preferably 50 μm or less. When the average ten-point height of the embossed outer surface of the interlayer is equal to or more than the lower limit and equal to or less than the upper limit, blocking between the films in the roll can be effectively prevented.

[0161] The ten-point mean roughness is measured in accordance with JIS B0601:1994. For example, a measuring device for measuring the ten-point mean roughness may be "Surfcorder SE500" manufactured by Kosaka Laboratory Co., Ltd. More specifically, the ten-point mean roughness can be measured using a stylus with a tip radius of 2 μm and a tip angle of 90° under the following measurement conditions: cutoff value at the time of measurement: 2.5 mm, reference length: 2.5 mm, measurement length: 12.5 mm, preliminary length: 2.5 mm, and palpation needle feed speed: 0.5 mm / sec, under an environment of 23° C. and 30% RH.

[0162] The above-mentioned average value of the ten-point average roughness can be measured, for example, as follows. Measurement points are taken at 5 cm intervals from one end of the interlayer film to the other end. At each measurement point, the angle of the measuring device is rotated by 45 degrees to measure the ten-point average roughness a total of eight times, and the maximum value is taken as the ten-point average roughness at each measurement point. The average value of the ten-point average roughness for the entire outer surface of the interlayer film is calculated from the ten-point average roughness at each measurement point.

[0163] The materials constituting each layer of the multi-layer interlayer film and the single-layer interlayer film will be described in detail below.

[0164] (thermoplastic resin) The intermediate film preferably contains a thermoplastic resin (hereinafter, may be referred to as thermoplastic resin (0)). The intermediate film preferably contains a polyvinyl acetal resin (hereinafter, may be referred to as polyvinyl acetal resin (0)) as the thermoplastic resin (0). The first layer preferably contains a thermoplastic resin (hereinafter, may be referred to as thermoplastic resin (1)). The first layer preferably contains a polyvinyl acetal resin (hereinafter, may be referred to as polyvinyl acetal resin (1)) as the thermoplastic resin (1). The second layer preferably contains a thermoplastic resin (hereinafter, may be referred to as thermoplastic resin (2)). The second layer preferably contains a polyvinyl acetal resin (hereinafter, may be referred to as polyvinyl acetal resin (2)) as the thermoplastic resin (2). The third layer preferably contains a thermoplastic resin (hereinafter, may be referred to as thermoplastic resin (3)). The third layer preferably contains a polyvinyl acetal resin (hereinafter, may be 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. Since sound insulation is further improved, the thermoplastic resin (1) is preferably different from the thermoplastic resin (2) and the thermoplastic resin (3). The polyvinyl acetal resin (1), the polyvinyl acetal resin (2), and the polyvinyl acetal resin (3) may be the same or different. Since sound insulation is further improved, the polyvinyl acetal resin (1) is preferably different from the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3). The thermoplastic resin (0), the thermoplastic resin (1), the thermoplastic resin (2), and the thermoplastic resin (3) may each be used alone or in combination of two or more. The polyvinyl acetal resin (0), the polyvinyl acetal resin (1), the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) may each be used alone or in combination of two or more kinds.

[0165] Examples of the thermoplastic resin include polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, polyurethane resin, polyvinyl alcohol resin, etc. Thermoplastic resins other than these may also be used as the thermoplastic resin.

[0166] The thermoplastic resin is preferably a polyvinyl acetal resin. By using a polyvinyl acetal resin in combination with a plasticizer, the adhesive strength of the layer containing the polyvinyl acetal resin and the plasticizer to the laminated glass member or other layer is further increased.

[0167] The polyvinyl acetal resin can be produced, for example, by acetalizing polyvinyl alcohol (PVA) with an aldehyde. The polyvinyl acetal resin is preferably 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 within the range of 70 to 99.9 mol%.

[0168] The average degree of polymerization of the polyvinyl alcohol (PVA) is preferably 200 or more, more preferably 500 or more, even more preferably 1500 or more, even more preferably 1600 or more, particularly preferably 2600 or more, most preferably 2700 or more, and preferably 5000 or less, more preferably 4000 or less, and even more preferably 3500 or less. When the average degree of polymerization is equal to or more than the lower limit, the penetration resistance of the laminated glass is further improved. When the average degree of polymerization is equal to or less than the upper limit, the interlayer film is easily formed.

[0169] The average degree of polymerization of the polyvinyl alcohol is determined by a method in accordance with JIS K6726 "Testing method for polyvinyl alcohol".

[0170] The number of carbon atoms in the acetal group contained in the polyvinyl acetal resin is not particularly limited. The aldehyde used in producing the polyvinyl acetal resin is not particularly limited. The number of carbon atoms in the acetal group in the 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 polyvinyl acetal resin is 3 or more, the glass transition temperature of the interlayer film becomes sufficiently low.

[0171] The aldehyde is not particularly limited. In general, an aldehyde having 1 to 10 carbon atoms is preferably used. Examples of the aldehyde having 1 to 10 carbon atoms include propionaldehyde, n-butylaldehyde, isobutylaldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, and benzaldehyde. Propionaldehyde, n-butylaldehyde, isobutylaldehyde, n-hexylaldehyde, or n-valeraldehyde is preferred, propionaldehyde, n-butylaldehyde, or isobutylaldehyde is more preferred, and n-butylaldehyde is even more preferred. The aldehyde may be used alone or in combination of two or more.

[0172] The hydroxyl group content (hydroxyl group amount) of the polyvinyl acetal resin (0) is preferably 15 mol% or more, more preferably 18 mol% or more, and preferably 40 mol% or less, more preferably 35 mol% or less. When the hydroxyl group content is equal to or more than the lower limit, the adhesive strength of the interlayer film is further increased. When the hydroxyl group content is equal to or less than the upper limit, the flexibility of the interlayer film is increased, making it easier to handle.

[0173] The hydroxyl group content (hydroxyl group amount) 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, and 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 equal to or more than 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 the productivity is excellent, and when it is 28 mol% or less, the sound insulation of the laminated glass is further increased. In addition, when the hydroxyl group content is equal to or less than the upper limit, the flexibility of the interlayer film is high, and the handling of the interlayer film is easy.

[0174] The hydroxyl group content of each 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 each 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 the lower limit or more, the adhesive strength of the interlayer film is further increased. When the hydroxyl group content is the upper limit or less, the flexibility of the interlayer film is increased, and the handling of the interlayer film is facilitated.

[0175] From the viewpoint of further improving the sound insulation, the hydroxyl group content of the polyvinyl acetal resin (1) is preferably lower than the hydroxyl group content of the polyvinyl acetal resin (2). From the viewpoint of further improving the sound insulation, the hydroxyl group content of the polyvinyl acetal resin (1) is preferably lower than the hydroxyl group content of the polyvinyl acetal resin (3). From the viewpoint of further improving the 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 content of the polyvinyl acetal resin (1) and the hydroxyl 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 content of the polyvinyl acetal resin (1) and the hydroxyl content of the polyvinyl acetal resin (2), and the absolute value of the difference between the hydroxyl content of the polyvinyl acetal resin (1) and the hydroxyl content of the polyvinyl acetal resin (3) are preferably 20 mol% or less.

[0176] The hydroxyl content of the polyvinyl acetal resin is a molar fraction calculated by dividing the amount of ethylene groups to which hydroxyl groups are bonded by the total amount of ethylene groups in the main chain, and expressed as a percentage. The amount of ethylene groups to which hydroxyl groups are bonded can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0177] The degree of acetylation (amount of acetyl groups) of the 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, and is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less. When the degree of acetylation is equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetylation is equal to or less than the upper limit, the moisture resistance of the interlayer film and the laminated glass is increased.

[0178] 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, even more preferably 9 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 24 mol% or less, and particularly preferably 20 mol% or less. When the degree of acetylation is equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetylation is equal to or less than the upper limit, the moisture resistance of the interlayer film and the laminated glass is increased. 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 penetration resistance is excellent.

[0179] The degree of acetylation of each 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, and preferably 10 mol% or less, more preferably 2 mol% or less. When the degree of acetylation is equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetylation is equal to or less than the upper limit, the moisture resistance of the interlayer film and the laminated glass is increased.

[0180] The degree of acetylation is a molar fraction calculated by dividing the amount of ethylene groups to which acetyl groups are bonded by the total amount of ethylene groups in the main chain, expressed as a percentage. The amount of ethylene groups to which acetyl groups are bonded can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0181] The degree of acetalization of the polyvinyl acetal resin (0) (the degree of butyralization in the case of a polyvinyl butyral resin) is preferably 60 mol% or more, more preferably 63 mol% or more, and 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 equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetalization is equal to or less than the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0182] The degree of acetalization of the polyvinyl acetal resin (1) (the degree of butyralization in the case of a polyvinyl butyral resin) is preferably 47 mol% or more, more preferably 60 mol% or more, and preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less. When the degree of acetalization is equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetalization is equal to or less than the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0183] The degree of acetalization of each of the polyvinyl acetal resin (2) and the polyvinyl acetal resin (3) (the degree of butyralization in the case of a polyvinyl butyral resin) is preferably 55 mol% or more, more preferably 60 mol% or more, and preferably 75 mol% or less, more preferably 71 mol% or less. When the degree of acetalization is equal to or more than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is increased. When the degree of acetalization is equal to or less than the upper limit, the reaction time required to produce the polyvinyl acetal resin is shortened.

[0184] The degree of acetalization is determined as follows. The amount of ethylene groups to which hydroxyl groups are bonded and the amount of ethylene groups to which acetyl groups are bonded are subtracted from the total amount of ethylene groups in the main chain. The mole fraction is determined by dividing the obtained value by the total amount of ethylene groups in the main chain. The resulting percentage is the degree of acetalization.

[0185] The hydroxyl group content (hydroxyl group amount), acetalization degree (butyralization degree), and acetylation degree are preferably calculated from the results measured by a method conforming to JIS K6728 "Testing Method for Polyvinyl Butyral". However, measurements according to ASTM D1396-92 may also be used. When the polyvinyl acetal resin is a polyvinyl butyral resin, the hydroxyl group content (hydroxyl group amount), acetalization degree (butyralization degree), and acetylation degree can be calculated from the results measured by a method conforming to JIS K6728 "Testing Method for Polyvinyl Butyral".

[0186] In 100% by weight of the thermoplastic resin contained in the interlayer, the content of the polyvinyl acetal resin 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 of the interlayer is preferably a polyvinyl acetal resin.

[0187] (Plasticizer) From the viewpoint of further increasing the adhesive strength of the interlayer film, the interlayer film preferably contains a plasticizer (hereinafter, may be referred to as plasticizer (0)). The first layer preferably contains a plasticizer (hereinafter, may be referred to as plasticizer (1)). The second layer preferably contains a plasticizer (hereinafter, may be referred to as plasticizer (2)). The third layer preferably contains a plasticizer (hereinafter, may be referred to as plasticizer (3)). When the thermoplastic resin contained in the interlayer film is a polyvinyl acetal resin, it is particularly preferable that the interlayer film (each layer) contains a plasticizer. The layer containing a polyvinyl acetal resin preferably contains a plasticizer.

[0188] The plasticizer is not particularly limited. Conventionally known plasticizers can be used as the plasticizer. The plasticizer may be used alone or in combination of two or more.

[0189] Examples of the plasticizer include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and organic phosphoric acid plasticizers such as organic phosphoric acid plasticizers and organic phosphorous acid plasticizers. The plasticizer is preferably an organic ester plasticizer. The plasticizer is preferably a liquid plasticizer.

[0190] The monobasic organic acid ester may be a glycol ester obtained by reacting a glycol with a monobasic organic acid. The glycol may be triethylene glycol, tetraethylene glycol, or tripropylene glycol. The monobasic organic acid may be butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octylic acid, 2-ethylhexyl acid, n-nonyl acid, or decyl acid.

[0191] Examples of the polybasic organic acid ester 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 polybasic organic acid include adipic acid, sebacic acid, and azelaic acid.

[0192] Examples of the organic ester plasticizer 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, di Examples of suitable plasticizers include ethylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate, 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 phosphoric acid ester and adipate. Other organic ester plasticizers may also be used. Other adipic acid esters than the above-mentioned adipic acid esters may also be used.

[0193] The organic phosphoric acid plasticizers include tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

[0194] The plasticizer is preferably a diester plasticizer represented by the following formula (1).

[0195] [ka]

[0196] In the above formula (1), 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 of 3 to 10. In the above formula (1), R1 and R2 each are preferably an organic group having 6 to 10 carbon atoms.

[0197] The plasticizer preferably comprises triethylene glycol di-2-ethylhexanoate (3GO) or triethylene glycol di-2-ethylbutyrate (3GH), more preferably triethylene glycol di-2-ethylhexanoate.

[0198] In the interlayer film, the content of the plasticizer (0) relative to 100 parts by weight of the thermoplastic resin (0) is defined as the content (0). The content (0) is preferably 25 parts by weight or more, more preferably 30 parts by weight or more, and 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. When the content (0) is equal to or more than the lower limit, the penetration resistance of the laminated glass is further increased. When the content (0) is equal to or less than the upper limit, the transparency of the interlayer film is further increased.

[0199] In the first layer, the content of the plasticizer (1) relative to 100 parts by weight of the thermoplastic resin (1) is defined as the 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, and is 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. When the content (1) is equal to or more than the lower limit, the flexibility of the interlayer film is increased, and the interlayer film is easy to handle. When the content (1) is equal to or less than the upper limit, the penetration resistance of the laminated glass is further increased.

[0200] In the second layer, the content of the plasticizer (2) relative to 100 parts by weight of the thermoplastic resin (2) is defined as the content (2). In the third layer, the content of the plasticizer (3) relative to 100 parts by weight of the thermoplastic resin (3) is defined as the content (3). The content (2) and the content (3) are each 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, and preferably 40 parts by weight or less, more preferably 35 parts by weight or less, even more preferably 32 parts by weight or less, particularly preferably 30 parts by weight or less. When the content (2) and the content (3) are equal to or more than the lower limit, the flexibility of the interlayer film is increased, and the handling of the interlayer film is facilitated. When the content (2) and the content (3) are equal to or less than the upper limit, the penetration resistance of the laminated glass is further increased.

[0201] In order to improve the sound insulation of the laminated glass, the content (1) is preferably greater than the content (2), and the content (1) is preferably greater than the content (3).

[0202] From the viewpoint of further improving the sound insulation of the laminated glass, the absolute value of the difference between the content (2) and the content (1) and the absolute value of the difference between the content (3) and the content (1) are each 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 content (2) and the content (1) and the absolute value of the difference between the content (3) and the content (1) are each 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.

[0203] (Heat-shielding material) The intermediate film preferably contains a heat-shielding material. The first layer preferably contains a heat-shielding material. The second layer preferably contains a heat-shielding material. The third layer preferably contains a heat-shielding material. Only one type of the heat-shielding material may be used, or two or more types may be used in combination.

[0204] The heat-shielding material preferably contains at least one component X selected from a phthalocyanine compound, a naphthalocyanine compound, and an anthracyanine compound, or contains heat-shielding particles. In this case, the heat-shielding material may contain both the component X and the heat-shielding particles.

[0205] Ingredient X: The interlayer film preferably contains at least one component X selected from a phthalocyanine compound, a naphthalocyanine compound, and an anthracyanine compound. The first layer preferably contains the component X. The second layer preferably contains the component X. The third layer preferably contains the component X. The component X is a heat-shielding material. Only one type of the component X may be used, or two or more types may be used in combination.

[0206] There is no particular limitation on the above-mentioned component X. As the component X, a conventionally known phthalocyanine compound, naphthalocyanine compound, or anthracyanine compound can be used.

[0207] The component X may be phthalocyanine, a derivative of phthalocyanine, naphthalocyanine, a derivative of naphthalocyanine, an anthracyanine, or a derivative of anthracyanine. The phthalocyanine compound and the derivative of phthalocyanine each preferably have a phthalocyanine skeleton. The naphthalocyanine compound and the derivative of naphthalocyanine each preferably have a naphthalocyanine skeleton. The anthracyanine compound and the derivative of anthracyanine each preferably have an anthracyanine skeleton.

[0208] From the viewpoint of further improving the heat insulation properties of the interlayer film and laminated glass, the above-mentioned component X is preferably 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.

[0209] From the viewpoint of effectively increasing the heat shielding property and maintaining the visible light transmittance at a higher level for a long period of time, the above component X preferably contains a vanadium atom or a copper atom. The above component X preferably contains a vanadium atom, and also preferably contains a copper atom. The above component X is more preferably 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 increasing the heat shielding property of the interlayer film and the laminated glass, the above component X preferably has a structural unit in which an oxygen atom is bonded to a vanadium atom.

[0210] In 100% by weight of the intermediate film or in 100% by weight of the layer containing the component X (first layer, second layer or third layer), the content of the 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 intermediate film or in 100% by weight of the layer containing the component X (first layer, second layer or third layer), the content of the 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 the component X is the above lower limit or more and the above upper limit or less, the heat shielding property is sufficiently high and the visible light transmittance is sufficiently high. For example, it is possible to make the visible light transmittance 70% or more.

[0211] Heat shielding particles: The intermediate film 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 a heat-shielding material. By using the heat-shielding particles, infrared rays (heat rays) can be effectively blocked. Only one type of the heat-shielding particles may be used, or two or more types may be used in combination.

[0212] From the viewpoint of further enhancing the heat shielding property of the laminated glass, the heat shielding particles are more preferably metal oxide particles.The heat shielding particles are preferably particles formed of a metal oxide (metal oxide particles).

[0213] Infrared rays, which have wavelengths of 780 nm or more, longer than visible light, have a smaller amount of energy than ultraviolet rays. However, infrared rays have a large thermal effect, and when infrared rays are absorbed by a substance, they are released as heat. For this reason, infrared rays are generally called heat rays. By using the above heat-shielding particles, infrared rays (heat rays) can be effectively blocked. Note that heat-shielding particles refer to particles that can absorb infrared rays.

[0214] Specific examples of the heat shielding particles include metal oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, antimony-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, and silicon-doped zinc oxide particles, as well as lanthanum hexaboride (LaB6) particles. Heat shielding particles other than these may also be used. Metal oxide particles are preferred because of their high heat ray 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 heat shielding particles include ITO particles or tungsten oxide particles, the heat shielding particles may include ITO particles and tungsten oxide particles. In particular, tin-doped indium oxide particles (ITO particles) are preferred because of their high heat ray shielding function and easy availability, and tungsten oxide particles are also preferred.

[0215] From the viewpoint of further improving the heat insulating properties of the interlayer film and the laminated glass, the tungsten oxide particles are preferably metal-doped tungsten oxide particles. The "tungsten oxide particles" include metal-doped tungsten oxide particles. Specific examples of the 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.

[0216] From the viewpoint of further increasing the heat insulating property of the interlayer film and the laminated glass, cesium-doped tungsten oxide particles are particularly preferred. From the viewpoint of further increasing the heat insulating property of the interlayer film and the laminated glass, the cesium-doped tungsten oxide particles are represented by the formula: Cs 0.33 Tungsten oxide particles represented by WO3 are preferred.

[0217] The average particle size of the heat shielding particles is preferably 0.01 μm or more, more preferably 0.02 μm or more, and is preferably 0.1 μm or less, more preferably 0.05 μm or less. When the average particle size is equal to or more than the lower limit, the heat shielding properties are sufficiently high. When the average particle size is equal to or less than the upper limit, the dispersibility of the heat shielding particles is high.

[0218] The "average particle size" refers to the volume average particle size. The average particle size can be measured using a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., "UPA-EX150") or the like.

[0219] The content of the heat shielding particles in 100% by weight of the intermediate film or in 100% by weight of the layer containing the heat shielding particles (the first layer, the second layer, or the third layer) 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. The content of the heat shielding particles in 100% by weight of the intermediate film or in 100% by weight of the layer containing the heat shielding particles (the first layer, the second layer, or the third layer) 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 heat shielding particles is equal to or more than the lower limit and equal to or less than the upper limit, the heat shielding property is sufficiently high and the visible light transmittance is sufficiently high.

[0220] (Metal Salts) The interlayer film preferably contains at least one metal salt (hereinafter, may be referred to as metal salt M) of an alkali metal salt and an alkaline earth metal salt. The first layer preferably contains the metal salt M. The second layer preferably contains the metal salt M. The third layer preferably contains the metal salt M. The alkaline earth metal means six metals, namely, Be, Mg, Ca, Sr, Ba, and Ra. The use of the metal salt M makes it easy to control the adhesion between the interlayer film and a laminated glass member such as a glass plate, or the adhesion between each layer in the interlayer film. Only one type of the metal salt M may be used, or two or more types may be used in combination.

[0221] The 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 film preferably contains at least one metal selected from the group consisting of K and Mg.

[0222] Moreover, the metal salt M is more preferably an alkali metal salt of an organic acid having 2 to 16 carbon atoms or an alkaline earth metal salt of an organic acid having 2 to 16 carbon atoms, and further preferably a magnesium salt of a carboxylate having 2 to 16 carbon atoms or a potassium salt of a carboxylate having 2 to 16 carbon atoms.

[0223] Examples of the magnesium salt of a carboxylate having 2 to 16 carbon atoms and the potassium salt of a carboxylate 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.

[0224] The total content of Mg and K in the interlayer containing the metal salt M or in the layer (first layer, second layer or third layer) containing the metal salt M is preferably 5 ppm or more, more preferably 10 ppm or more, even more preferably 20 ppm or more, and 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 equal to or more than the above lower limit and equal to or less than the above upper limit, the adhesion between the interlayer and the glass plate or the adhesion between the layers in the interlayer can be controlled more effectively.

[0225] (UV protection agent) The interlayer film preferably contains an ultraviolet shielding agent. The first layer preferably contains an ultraviolet shielding agent. The second layer preferably contains an ultraviolet shielding agent. The third layer preferably contains an ultraviolet shielding agent. By using an ultraviolet shielding agent, the visible light transmittance is more unlikely to decrease even when the interlayer film and the laminated glass are used for a long period of time. Only one type of ultraviolet shielding agent may be used, or two or more types may be used in combination.

[0226] The ultraviolet shielding agent includes an ultraviolet absorbing agent. The ultraviolet shielding agent is preferably an ultraviolet absorbing agent.

[0227] Examples of the ultraviolet ray shielding agent include ultraviolet ray shielding agents containing metal atoms, ultraviolet ray shielding agents containing metal oxides, ultraviolet ray shielding agents having a benzotriazole structure (benzotriazole compounds), ultraviolet ray shielding agents having a benzophenone structure (benzophenone compounds), ultraviolet ray shielding agents having a triazine structure (triazine compounds), ultraviolet ray shielding agents having a malonic acid ester structure (malonic acid ester compounds), ultraviolet ray shielding agents having an oxalic acid anilide structure (oxalic acid anilide compounds), and ultraviolet ray shielding agents having a benzoate structure (benzoate compounds).

[0228] Examples of the ultraviolet shielding agent containing the metal atom include platinum particles, platinum particles whose surfaces are coated with silica, palladium particles, and palladium particles whose surfaces are coated with silica, etc. It is preferable that the ultraviolet shielding agent is not a heat shielding particle.

[0229] The 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 ultraviolet shielding agent is more preferably an ultraviolet shielding agent having a benzotriazole structure or an ultraviolet shielding agent having a benzophenone structure, and further preferably an ultraviolet shielding agent having a benzotriazole structure.

[0230] Examples of the ultraviolet shielding agent containing the metal oxide include zinc oxide, titanium oxide, and cerium oxide. Furthermore, the ultraviolet shielding agent containing the metal oxide may be surface-coated. Examples of the surface-coating material of the ultraviolet shielding agent containing the metal oxide include insulating metal oxides, hydrolyzable organic silicon compounds, and silicone compounds.

[0231] The insulating metal oxide includes silica, alumina, zirconia, etc. The insulating metal oxide has a band gap energy of, for example, 5.0 eV or more.

[0232] Examples of the ultraviolet shielding agent having the 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'-di-amylphenyl)benzotriazole (BASF's "Tinuvin 328"), etc. Since the ultraviolet shielding agent has excellent ultraviolet shielding performance, it is preferable that the ultraviolet shielding agent has a benzotriazole structure containing a halogen atom, and more preferably has a benzotriazole structure containing a chlorine atom.

[0233] Examples of the ultraviolet screening agent having a benzophenone structure include octabenzone ("Chimassorb 81" manufactured by BASF).

[0234] Examples of the ultraviolet screening agent having a triazine structure include "LA-F70" manufactured by ADEKA Corporation and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol ("Tinuvin 1577FF" manufactured by BASF).

[0235] Examples of the ultraviolet screening agent having a 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-pentamethyl-4-piperidinyl)malonate.

[0236] Commercially available ultraviolet screening agents having the above malonic acid ester structure include Hostavin B-CAP, Hostavin PR-25, and Hostavin PR-31 (all manufactured by Clariant).

[0237] Examples of ultraviolet screening 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-oxalanilide ("Sanduvor VSU" manufactured by Clariant).

[0238] Examples of the ultraviolet screening agent having a benzoate structure include 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate ("Tinuvin 120" manufactured by BASF).

[0239] In 100% by weight of the intermediate film or in 100% by weight of the layer (first layer, second layer or third layer) containing the ultraviolet ray shielding agent, the content of the ultraviolet ray 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 intermediate film or in 100% by weight of the layer (first layer, second layer or third layer) containing the ultraviolet ray shielding agent, the content of the ultraviolet ray 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 ultraviolet ray shielding agent is the above lower limit or more and the above upper limit or less, the decrease in visible light transmittance after a period of time can be further suppressed. In particular, by having the content of the ultraviolet ray shielding agent be 0.2% by weight or more in 100% by weight of the layer containing the ultraviolet ray shielding agent, it is possible to significantly suppress the decrease in visible light transmittance of the interlayer film and laminated glass over a period of time.

[0240] (Antioxidants) The intermediate film preferably contains an antioxidant. The first layer preferably contains an antioxidant. The second layer preferably contains an antioxidant. The third layer preferably contains an antioxidant. Only one type of antioxidant may be used, or two or more types may be used in combination.

[0241] The antioxidants include phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. The phenol-based antioxidants are antioxidants having a phenol skeleton. The sulfur-based antioxidants are antioxidants containing sulfur atoms. The phosphorus-based antioxidants are antioxidants containing phosphorus atoms.

[0242] The antioxidant is preferably a phenol-based antioxidant or a phosphorus-based antioxidant.

[0243] The phenol-based antioxidants include 2,6-di-t-butyl-p-cresol (BHT), butyl hydroxyanisole (BHA), 2,6-di-t-butyl-4-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis-(4-methyl-6-butylphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), 4,4'-butylidene-bis-(3-methyl-6-t-butylphenol), 1,1,3-tris-(2-methyl-hydroxy-5- t-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.

[0244] Examples of the phosphorus-based antioxidant 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, etc. One or more of these antioxidants are preferably used.

[0245] Commercially available examples of the antioxidant include "IRGANOX 245" manufactured by BASF, "IRGAFOS 168" manufactured by BASF, "IRGAFOS 38" manufactured by BASF, "Sumilizer BHT" manufactured by Sumitomo Chemical Co., Ltd., "H-BHT" manufactured by Sakai Chemical Industry Co., Ltd., and "IRGANOX 1010" manufactured by BASF.

[0246] In order to maintain the high visible light transmittance of the interlayer film and the laminated glass for a long period of time, the content of the antioxidant in 100% by weight of the interlayer film or in 100% by weight of the layer containing the antioxidant (first layer, second layer or third layer) is preferably 0.1% by weight or more. In addition, since the effect of adding the antioxidant becomes saturated, the content of the antioxidant in 100% by weight of the interlayer film or in 100% by weight of the layer containing the antioxidant is preferably 2% by weight or less.

[0247] (Other ingredients) The intermediate film, the first layer, the second layer and the third layer may each contain additives such as coupling agents, dispersants, surfactants, flame retardants, antistatic agents, pigments, dyes, adhesion regulators other than metal salts, moisture resistant agents, fluorescent brighteners and infrared absorbing agents, as necessary. These additives may be used alone or in combination of two or more.

[0248] (Laminated glass) FIG. 5 is a cross-sectional view showing an example of laminated glass using the interlayer film for laminated glass shown in FIG.

[0249] The laminated glass 21 shown in Fig. 5 includes an interlayer film 11, a first laminated glass member 22, and a second laminated glass member 23. The interlayer film 11 is disposed and sandwiched between the first laminated glass member 22 and the second laminated glass member 23. The first laminated glass member 22 is disposed on a first surface of the interlayer film 11. The second laminated glass member 23 is disposed on a second surface of the interlayer film 11 opposite to the first surface.

[0250] Examples of the laminated glass member include glass plates and PET (polyethylene terephthalate) films. The laminated glass includes not only a laminated glass having an intermediate film sandwiched between two glass plates, but also a laminated glass having an intermediate film sandwiched between a glass plate and a PET film or the like. The laminated glass is a laminate including glass plates, and preferably contains at least one glass plate. It is preferable that the first laminated glass member and the second laminated glass member are glass plates or PET (polyethylene terephthalate) films, respectively, and that the intermediate film contains 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.

[0251] The glass plate includes inorganic glass and organic glass. The inorganic glass includes float plate glass, heat absorbing plate glass, heat reflecting plate glass, polished plate glass, patterned plate glass, lined plate glass, green glass, etc. The organic glass is a synthetic resin glass that replaces inorganic glass. The organic glass includes polycarbonate plate and poly(meth)acrylic resin plate, etc. The poly(meth)acrylic resin plate includes polymethyl(meth)acrylate plate, etc.

[0252] The thickness of each of the first laminated glass member and the second laminated glass member 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.

[0253] The method for producing the laminated glass 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 allows air remaining between the first laminated glass member and the interlayer film and between the second laminated glass member and the interlayer film to be degassed. Then, preliminary bonding is performed at about 70°C to 110°C to obtain a laminate. Next, the laminate is placed in an autoclave or pressed, and pressure-bonded at about 120°C to 150°C and a pressure of 1 MPa to 1.5 MPa. In this manner, a laminated glass can be obtained.

[0254] The laminated glass can be used for automobiles, railroad cars, aircraft, ships, buildings, etc. The laminated glass is preferably a laminated glass for buildings or vehicles, more preferably a laminated glass for vehicles. The laminated glass can be used for purposes other than these. The laminated glass can be used for automobile front glass, side glass, rear glass, roof glass, etc. Since the laminated glass has high heat shielding properties and high visible light transmittance, it is suitable for use in automobiles.

[0255] The laminated glass is preferably a head-up display (HUD) laminated glass. In the HUD laminated glass, measurement information such as speed transmitted from a control unit can be projected onto the windshield from a display unit of an instrument panel. This allows the driver of the vehicle to simultaneously view the front view and the measurement information without lowering his or her field of vision.

[0256] A head-up display system can be obtained by using the head-up display. The head-up display system includes the laminated glass and a light source device for irradiating the laminated glass with light for image display. The light source device can be attached to a dashboard of a vehicle, for example. An image can be displayed by irradiating the display area of ​​the laminated glass with light from the light source device.

[0257] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0258] In the polyvinyl acetal resin used, n-butyl aldehyde with 4 carbon atoms was used for acetalization. For the polyvinyl acetal resin, the degree of acetalization (degree of butyralization), the degree of acetylation, and the content of hydroxyl groups were measured by a method conforming to JIS K6728 "Testing Method for Polyvinyl Butyral." When measured by ASTM D1396-92, the values ​​were similar to those obtained by a method conforming to JIS K6728 "Testing Method for Polyvinyl Butyral."

[0259] The following materials were prepared:

[0260] Example 1 Preparation of the composition for forming the interlayer (first layer): The following components were mixed and thoroughly kneaded with a mixing roll to obtain a composition for forming an interlayer film.

[0261] Polyvinyl acetal resin (average degree of polymerization 1700, hydroxyl group content 30.5 mol%, acetylation degree 1.0 mol%, acetalization degree 68.5 mol%) 100 parts by weight Triethylene glycol di-2-ethylhexanoate (3GO) 40 parts by weight Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, "Tinuvin 326" manufactured by BASF) in an amount of 0.2% by weight in the resulting interlayer film BHT (2,6-di-t-butyl-p-cresol) in an amount that results in 0.2% by weight of the resulting interlayer film

[0262] Preparation of the interlayer: The composition for forming the interlayer film was extruded using an extruder, and the interlayer film was wound up to obtain a roll body. In this way, a wedge-shaped interlayer film having a structure of only the first layer was produced.

[0263] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end, and the distance U between the one end and the other end was 1200 mm.

[0264] In Example 1, an interlayer film was produced in which the region of increasing thickness had a portion where the increase in thickness decreased from one end to the other end, and the region having a wedge-shaped cross section in the thickness direction had a portion where the wedge angle decreased from one end to the other end (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.40 mrad.

[0265] Example 2 Preparation of the 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.

[0266] Polyvinyl acetal resin (average degree of polymerization 3000, hydroxyl group content 22 mol%, acetylation degree 13 mol%, acetalization degree 65 mol%) 100 parts by weight Triethylene glycol di-2-ethylhexanoate (3GO) 60 parts by weight Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, "Tinuvin 326" manufactured by BASF) in an amount of 0.2% by weight in the resulting first layer. BHT (2,6-di-t-butyl-p-cresol) in an amount of 0.2% by weight in the resulting first layer

[0267] 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 layer and the third layer.

[0268] Polyvinyl acetal resin (average polymerization degree 1700, hydroxyl group content 30.5 mol%, acetylation degree 1 mol%, acetalization degree 68.5 mol%) 100 parts by weight Triethylene glycol di-2-ethylhexanoate (3GO) 38 parts by weight Tinuvin 326 (2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, "Tinuvin 326" manufactured by BASF) in an amount of 0.2% by weight in the resulting second and third layers. BHT (2,6-di-t-butyl-p-cresol) in an amount of 0.2% by weight in the resulting second and third layers

[0269] Preparation of the interlayer: The composition for forming the first layer and the compositions for forming the second and third layers were co-extruded using an extruder, and the interlayer film was wound up to obtain a roll body. In this way, a wedge-shaped interlayer film having a laminated structure of the second layer / the first layer / the third layer was produced.

[0270] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end, and the distance U between the one end and the other end was 1000 mm.

[0271] In Example 2, an interlayer film was produced in which the region of increasing thickness had a portion where the increase in thickness decreased from one end to the other end, and the region having a wedge-shaped cross section in the thickness direction had a portion where the wedge angle decreased from one end to the other end (see FIG. 1 for the outer shape). The wedge angle of the entire interlayer film was 0.44 mrad.

[0272] Example 3 A wedge-shaped interlayer film having a structure consisting of only the first layer was produced in the same manner as in Example 1, except that the shape of the die outlet was adjusted.

[0273] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end. The distance U between the one end and the other end was 1120 mm.

[0274] In Example 3, an interlayer film was produced in which the region of increasing thickness had a portion where the increase in thickness decreased from one end to the other end, and the region having a wedge-shaped cross section in the thickness direction had a portion where the wedge angle decreased from one end to the other end (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.41 mrad.

[0275] Example 4 A wedge-shaped interlayer film having a laminated structure of the second layer / first layer / third layer was produced in the same manner as in Example 2, except that the shape of the die outlet was adjusted and the degree of kneading in the melting section of the extruder was changed.

[0276] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end, and the distance U between the one end and the other end was 1100 mm.

[0277] In Example 4, an interlayer film was produced in which, in a region of increasing thickness, there was a portion where the increase in thickness decreased from one end side to the other end side, and, in a region having a wedge-shaped cross section in the thickness direction, there was a portion where the wedge angle decreased from one end side to the other end side (see FIG. 1 for the outer shape). The wedge angle of the entire interlayer film was 0.70 mrad.

[0278] Comparative Example 1 A wedge-shaped interlayer film having a structure consisting of only the first layer was produced in the same manner as in Example 1, except that the shape of the die outlet was changed.

[0279] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end. The distance U between the one end and the other end was 1110 mm.

[0280] In Comparative Example 1, an interlayer film was produced in which, in a region of increasing thickness, there was a portion where the increase in thickness decreased from one end side to the other end side, and, in a region having a wedge-shaped cross section in the thickness direction, there was a portion where the wedge angle decreased from one end side to the other end side (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.44 mrad.

[0281] Comparative Example 2 A wedge-shaped interlayer film having a laminated structure of the second layer / first layer / third layer was produced in the same manner as in Example 2, except that the shape of the die outlet was adjusted and the degree of kneading of the resin composition in the extruder melting section was changed.

[0282] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end. The distance U between the one end and the other end was 1215 mm.

[0283] In Comparative Example 2, an interlayer film was produced in which, in a region of increasing thickness, there was a portion where the increase in thickness decreased from one end side to the other end side, and, in a region having a wedge-shaped cross section in the thickness direction, there was a portion where the wedge angle decreased from one end side to the other end side (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.83 mrad.

[0284] Comparative Example 3 A wedge-shaped interlayer film having a structure consisting of only the first layer was produced in the same manner as in Example 1, except that the shape of the die outlet was adjusted.

[0285] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end, and the distance U between the one end and the other end was 1000 mm.

[0286] In Comparative Example 3, an interlayer film was produced in which, in a region of increasing thickness, there was a portion where the increase in thickness decreased from one end side to the other end side, and, in a region having a wedge-shaped cross section in the thickness direction, there was a portion where the wedge angle decreased from one end side to the other end side (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.51 mrad.

[0287] Comparative Example 4 A wedge-shaped interlayer film having a laminated structure of the second layer / first layer / third layer was produced in the same manner as in Example 2, except that the temperature of the resin composition at the extruder outlet was changed.

[0288] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end. The distance U between the one end and the other end was 988 mm.

[0289] In Comparative Example 4, an interlayer film was produced in which, in a region of increasing thickness, there was a portion where the increase in thickness decreased from one end side to the other end side, and, in a region having a wedge-shaped cross section in the thickness direction, there was a portion where the wedge angle decreased from one end side to the other end side (see FIG. 1 for the outer shape). The wedge angle of the entire interlayer film was 0.62 mrad.

[0290] Comparative Example 5 A wedge-shaped interlayer film having a structure of only the first layer was produced in the same manner as in Example 1, except that the shape of the die outlet and the degree of kneading of the resin composition in the melting section of the extruder were adjusted.

[0291] The obtained interlayer film had a minimum thickness at one end and a maximum thickness at the other end, and the distance U between the one end and the other end was 1000 mm.

[0292] In Comparative Example 5, an interlayer film was produced in which the region of increasing thickness had a portion where the increase in thickness decreased from one end to the other end, and the region having a wedge-shaped cross section in the thickness direction had a portion where the wedge angle decreased from one end to the other end (see FIG. 2 for the outer shape). The wedge angle of the entire interlayer film was 0.71 mrad.

[0293] (evaluation) (1) Maximum absolute value of the deviation of the slope of the approximation line and the partial wedge angle In each section A, the deviation of the formula of the approximate line A and the partial wedge angle was calculated, and the maximum absolute value of the deviation of the slope of the approximate line A and the partial wedge angle was calculated. In Example 4 and Comparative Example 5, the deviation of the formula of the approximate line B and the partial wedge angle was calculated, and the maximum absolute value of the deviation of the slope of the approximate line B and the partial wedge angle was also calculated. Tables 1 and 2 show the maximum absolute values ​​of the deviation of the slope of the approximate line and the partial wedge angle in a specific section A. In the interlayer films obtained in Comparative Examples 1 to 5, there was no section A that satisfied the configuration in which "the slope of the approximate line is -0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less."

[0294] (2) Reflected double images in the HUD area A pair of glass plates (clear glass, 510 mm×1100 mm in size, 2.0 mm in thickness) was prepared. An interlayer film having a size corresponding to the size of the glass plates was sandwiched between the pair of glass plates to obtain a laminate. The obtained laminate was fitted into an EPDM rubber tube (frame member) as shown in FIG. 8. The width of the rubber tube was 15 mm. Next, the laminate fitted into the EPDM rubber tube was pre-pressed by a vacuum bag method. The pre-pressed laminate was pressed at 150° C. and a pressure of 1.2 MPa using an autoclave to obtain a laminated glass.

[0295] The obtained laminated glass was placed at the position of the windshield. Display information from a display unit (focal length: 2m, 3m, and 4m) placed below the laminated glass was reflected onto the laminated glass, and the presence or absence of double images was visually confirmed at a specified position (entire display area). Double images in the HUD area were judged according to the following criteria.

[0296] [Criteria for determining reflected double images in the HUD area] ○○: No double image observed ○: A slight amount of double reflected images was observed, but it did not affect practical use. ×: Does not meet the criteria for ○○ and ○

[0297] (3) Transparent double image (2) Using the laminated glass obtained with the reflected double image in the HUD area, the transmitted double image was measured based on the double image test described in JIS R3212.

[0298] [Criteria for determining transparent double images] ○: The maximum separation between the primary and secondary images does not exceed 25 minutes. ×: The maximum separation between the primary and secondary images exceeds 25 minutes.

[0299] (4) An area having a ten-point mean roughness within ±30% of the average ten-point mean roughness of the entire embossed outer surface The ten-point average roughness of the outer surface of the interlayer was measured in accordance with JIS B0601:1994. The measuring device used was the "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. The measurement was performed using a stylus with a tip radius of 2 μm and a tip angle of 60° under the following measurement conditions: cutoff value at the time of measurement: 2.5 mm, reference length: 2.5 mm, measurement length: 12.5 mm, reserve length: 2.5 mm, and palpation needle feed speed: 0.5 mm / sec, under an environment of 23°C and 30 RH%. The ten-point average roughness of the outer surface of the interlayer was measured by the following method. The measurement points were points spaced 5 cm apart from one end of the interlayer to the other end. At each measurement point, the angle of the measuring device was rotated by 45° to measure the ten-point average roughness a total of eight times, and the maximum value was taken as the ten-point average roughness at each measurement point. From the ten-point average roughness of each measurement point, the average ten-point average roughness of the entire outer surface of the interlayer was calculated, and the area (%) of the outer surface of the interlayer having a ten-point average roughness within ±30% of the average ten-point average roughness of the entire embossed outer surface was determined.

[0300] (5) Heat shrinkage rate The obtained interlayer film was cut out to a size of 10 cm in the MD direction from one end to the other end in the TD direction. After cutting, the film was conditioned for 2 days at a temperature of 20°C and a humidity of 30% RH. Then, as shown in FIG. 7, test pieces were cut out at a first position of 0.05U from one end to the other end, a second position of 0.5U from one end to the other end, and a third position of 0.95U from one end to the other end. The test piece was a square of 5 cm in the MD direction and 5 cm in the TD direction. The test piece was cut out at the center of the test piece in the MD direction. The test piece was cut out so that the first position, the second position, and the third position were in the center.

[0301] The obtained test piece was placed horizontally on a fluororesin sheet and left at 150°C for 0.5 hours. The dimensions in the MD direction were measured before and after leaving it, and the thermal shrinkage was calculated using the following formula. Of the three thermal shrinkages obtained, the absolute value of the difference between the maximum and minimum thermal shrinkages was calculated.

[0302] Heat shrinkage rate (%) = ((dimension in MD direction before heating - dimension in MD direction after heating) / dimension in MD direction before heating) x 100

[0303] Details and results are shown in Tables 1 and 2 below.

[0304] [Table 1]

[0305] [Table 2] [Explanation of symbols]

[0306] 1, 1A, 1B, 1C...First layer 1Aa: Section with a rectangular cross-sectional shape in the thickness direction 1Ab: Section with a wedge-shaped cross section in the thickness direction 2,2B…Second layer 3,3B…Third layer 11,11A,11B,11C...intermediate film 11a…one end 11b...other end 11Aa: Section with rectangular cross-sectional shape in the thickness direction 11Ab: A portion having a wedge-shaped cross section 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. A wire has one end and another end opposite the one end, The thickness of the other end is greater than the thickness of the one end, An interlayer film for laminated glass, wherein, when the slope of approximate line A and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the following formula for approximate line A and calculation of the deviation of the partial wedge angle, in at least one section A, the slope of the approximate line A is −0.05 mrad / m or less and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. Calculation of the equation of approximate straight line A and the deviation of the partial wedge angle: Calculate the equation of approximate straight line A and the deviation of the partial wedge angle in the order of 1 to 4 below. 1: A position 40 mm from the one end of the intermediate film toward the other end is defined as a start point X, and a position 40 mm from the other end of the intermediate film toward the one end is defined as an end point X. Points A are selected at 1 mm intervals from the start point X toward the end point X. 2: Calculate the partial wedge angle A in each 80 mm partial area A in the direction connecting the one end and the other end with each point A as the center, to obtain the "partial wedge angle A at each point A." 3: The start point Y is a position 190 mm from the one end of the intermediate film toward the other end, and the end point Y is a position 190 mm from the other end of the intermediate film toward the one end. Sections A of 300 mm each are set at 1 mm intervals from the start point Y to the end point Y so that the center of each section A is located between the start point Y and the end point Y. 4: Determine the equation of the approximate straight line A below and the deviation of the partial wedge angle below. Equation of approximate straight line A: In each of sections A, from the "partial wedge angle A at each point A" where the point A exists within the section A, an approximate straight line is created with the x-axis direction set to the "distance from the one end of the interlayer film" and the y-axis direction set to the "partial wedge angle A," and the equation of the approximate straight line A in each section A is determined. Deviation of partial wedge angle: The partial wedge angle A' at each point A is calculated from the equation of the approximation line A to obtain the "partial wedge angle A' at each point A on the approximation line A." For each section A, the deviation of the partial wedge angle in each section A is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A' at each point A on the approximate line A" where the point A exists within the section A.

2. 2. The interlayer film for laminated glass according to claim 1, wherein in at least one section A included between a position 100 mm from the one end toward the other end of the interlayer film and a position 600 mm from the one end toward the other end of the interlayer film, the slope of the approximate straight line A is −0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

3. 3. The interlayer film for laminated glass according to claim 1, wherein in at least one section A included between a position 600 mm from the one end toward the other end of the interlayer film and the other end of the interlayer film, the gradient of the approximate straight line A is −0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less.

4. The interlayer film for laminated glass according to any one of claims 1 to 3, wherein, when the slope of the approximate line B and the maximum absolute value of the deviation of the partial wedge angle are calculated based on the following formula for the approximate line B and calculation of the deviation of the partial wedge angle, in section B, the slope of the approximate line B is -0.05 mrad / m or less, and the maximum absolute value of the deviation of the partial wedge angle is 0.2 mrad or less. Calculation of the equation of the approximate straight line B and the deviation of the partial wedge angle: Calculate the equation of the approximate straight line B and the deviation of the partial wedge angle in the order of 5 and 6 below. 5: A section between a position 50 mm from the one end of the intermediate film toward the other end and a position 50 mm from the other end of the intermediate film toward the one end is set as section B. 6: Determine the equation of the approximate straight line B below and the deviation of the partial wedge angle below. Equation of approximate straight line B: In section B, from the "partial wedge angle A at each point A" where point A exists within section B, an approximate straight line B is created with the x-axis direction set to the "distance from the one end of the interlayer film" and the y-axis direction set to the "partial wedge angle A," and the equation of approximate straight line B in section B is determined. Deviation of partial wedge angle: The partial wedge angle A'' at each point A is calculated from the equation of the approximation line B to obtain the "partial wedge angle A'' at each point A on the approximation line B." In section B, the deviation of the partial wedge angle in section B is calculated from the "partial wedge angle A at each point A" and the "partial wedge angle A'' at each point A on the approximation line B" where the point A exists within the section B.

5. The interlayer film for laminated glass according to any one of claims 1 to 4, wherein at least one outer surface of the interlayer film is embossed.

6. 6. The interlayer film for laminated glass according to claim 5, wherein 50% or more of an area of ​​the embossed outer surface of the interlayer film has a ten-point height difference within ±30% of the average ten-point height difference of the entire embossed outer surface of the interlayer film.

7. 7. The interlayer film for laminated glass according to claim 1, wherein, when a distance between the one end and the other end of the interlayer film is U, an absolute value of a difference between a maximum heat shrinkage rate and a minimum heat shrinkage rate among three heat shrinkage rates: a first heat shrinkage rate at 150°C in the MD direction at a first position of 0.05U from the one end toward the other end, a second heat shrinkage rate at 150°C in the MD direction at a second position of 0.5U from the one end toward the other end, and a third heat shrinkage rate at 150°C in the MD direction at a third position of 0.95U from the one end toward the other end, is 15% or less.

8. The interlayer film for laminated glass according to any one of claims 1 to 7, having a maximum thickness of 1700 µm or less.

9. A winding core and The interlayer film for laminated glass according to any one of claims 1 to 8, The interlayer film for laminated glass is wound around the outer periphery of the winding core.

10. a first laminated glass member; a second laminated glass member; and The interlayer film for laminated glass according to any one of claims 1 to 8, The laminated glass, wherein the interlayer film for laminated glass is disposed between the first laminated glass member and the second laminated glass member.

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