Interlayer film for laminated glass and laminated glass

Abstract

Provided is an interlayer film for laminated glass in which it is possible to suppress the occurrence of gaps in the interlayer film at the edge of the laminated glass despite using an interlayer film in which the amount of increase in thickness is not uniform from one end to the other end.　The interlayer film for laminated glass according to the present invention includes a light stabilizer and an antioxidant, has one end and another end that is thicker than the one end and is on the side opposite from the one end, and is such that the amount of increase in thickness from the one end to the other end is not uniform.

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 laminated glass using the interlayer film for laminated glass. [Background technology]

[0002] Laminated glass is excellent in safety because it generates only a small amount of glass fragments even when broken by external impact. For this reason, laminated glass is widely used in automobiles, railway vehicles, aircraft, ships, buildings, etc. Laminated glass is manufactured by sandwiching an interlayer film between a pair of glass sheets.

[0003] Known interlayer films include those with a rectangular cross-sectional shape in the thickness direction and those with a wedge-shaped cross-sectional shape in the thickness direction. Also known as wedge-shaped interlayer films are those with a constant increase in thickness from one end to the other, as shown in Figures 1, 3, and 5 of Patent Document 1 below, and those with a non-constant increase in thickness from one end to the other, as shown in Figures 2, 4, 6, and 7 of Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2017 / 104632A1 Summary of the Invention [Problem to be solved by the invention]

[0005] Laminated glass is usually produced by pressing an interlayer film and a laminated glass member together.

[0006] When an interlayer film having a rectangular cross-sectional shape in the thickness direction or an interlayer film having a constant increase in thickness from one end to the other end is used, the laminated glass member is not deformed when the interlayer film and the laminated glass member are pressure-bonded together.

[0007] On the other hand, when an interlayer film whose thickness does not increase uniformly from one end to the other is used, the laminated glass element bends and deforms along the outer shape of the interlayer film when the interlayer film and the laminated glass element are pressure-bonded together. As a result, in the resulting laminated glass, a force is generated at the edges of the laminated glass element that causes the laminated glass element to return to its original shape, and an accompanying force is generated at the edges of the interlayer film that are adhered to the laminated glass element that is pulling outward in the thickness direction.

[0008] Therefore, in laminated glass obtained using an interlayer film whose thickness does not increase uniformly from one end to the other, the interlayer film is prone to deterioration at the edges of the laminated glass. Furthermore, when this laminated glass is exposed to light, heat, and the like, the interlayer film is more prone to deterioration at the edges of the laminated glass. Deterioration of the interlayer film at the edges of the laminated glass can result in voids in the interlayer film. These voids are depressions where the interlayer film is missing at the edges of the laminated glass.

[0009] An object of the present invention is to provide an interlayer film for laminated glass that can suppress the occurrence of voids in the interlayer film at the edges of the laminated glass, even when the interlayer film does not increase in thickness uniformly from one end to the other. Another object of the present invention is to provide laminated glass that uses the above interlayer film for laminated glass. [Means for solving the problem]

[0010] According to a broad aspect of the present invention, there is provided an interlayer film for laminated glass (hereinafter, may be referred to as an interlayer film), which contains a light stabilizer and an antioxidant, has one end and another end opposite the one end that is thicker than the one end, and the amount of increase in thickness from the one end to the other end is not constant.

[0011] In a specific aspect of the interlayer film according to the present invention, the light stabilizer is a hindered amine light stabilizer in which a carbon atom or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure.

[0012] In a specific aspect of the interlayer film according to the present invention, the antioxidant is a phenolic antioxidant.

[0013] In a specific aspect of the interlayer film according to the present invention, the molecular weight of the antioxidant is 220 or more.

[0014] In a specific aspect of the interlayer film according to the present invention, the content of the light stabilizer in 100% by weight of the layer containing the light stabilizer is 0.01% by weight or more and 0.5% by weight or less.

[0015] In a specific aspect of the interlayer film according to the present invention, the content of the antioxidant is 0.1% by weight or more and 2% by weight or less, relative to 100% by weight of the layer containing the antioxidant.

[0016] In a specific aspect of the interlayer film according to the present invention, the content of the light stabilizer on a weight basis is distributed in the direction connecting the one end and the other end such that the content of the light stabilizer on a weight basis is higher on the other end side in the direction connecting the one end and the other end, and the content of the antioxidant on a weight basis is distributed in the direction connecting the one end and the other end such that the content of the antioxidant on a weight basis is higher on the other end side in the direction connecting the one end and the other end.

[0017] In a specific aspect of the interlayer film according to the present invention, the interlayer film has at least one of the following configurations (1) to (3).

[0018] Configuration (1): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and within the region in which the thickness increases, there is a portion in which the amount of increase in thickness varies from the one end side to the other end side.

[0019] Configuration (2): The intermediate film has a portion in a region where the cross section in the thickness direction is wedge-shaped, where the wedge angle varies from the one end side to the other end side.

[0020] Configuration (3): The intermediate film has a portion whose cross section in the thickness direction is rectangular and a portion whose cross section in the thickness direction is wedge-shaped.

[0021] In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a first layer and a second layer disposed on a first surface side of the first layer.

[0022] In a specific aspect of the interlayer film according to the present invention, the first layer contains a polyvinyl acetal resin and a plasticizer, and the second layer contains a polyvinyl acetal resin and a plasticizer.

[0023] In a specific aspect of the interlayer film according to the present invention, the hydroxyl group content of the polyvinyl acetal resin in the first layer is lower than the hydroxyl group content of the polyvinyl acetal resin in the second layer.

[0024] In a specific aspect of the interlayer film according to the present invention, the content of the plasticizer in the first layer per 100 parts by weight of the polyvinyl acetal resin in the first layer is greater than the content of the plasticizer in the second layer per 100 parts by weight of the polyvinyl acetal resin in the second layer.

[0025] In a specific aspect of the interlayer film according to the present invention, the first layer contains the light stabilizer and the antioxidant.

[0026] According to a broad aspect of the present invention, there is provided laminated glass comprising a first laminated glass element, a second laminated glass element, and the above-described interlayer film for laminated glass, with the interlayer film for laminated glass disposed between the first laminated glass element and the second laminated glass element. [Effects of the Invention]

[0027] The interlayer film according to the present invention contains a light stabilizer and an antioxidant, has one end and another end opposite the one end that is thicker than the one end, and the amount of increase in thickness from the one end to the other end is not uniform. Because the interlayer film according to the present invention has the above configuration, it is possible to suppress the occurrence of voids in the interlayer film at the edges of the laminated glass, despite the use of an interlayer film whose amount of increase in thickness is not uniform from one end to the other. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an interlayer film for laminated glass according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a third embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a fourth embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a fifth embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a sixth embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a seventh embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view schematically showing an interlayer film for laminated glass according to an eighth embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a ninth embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a tenth embodiment of the present invention. [Figure 11]FIG. 11 is a cross-sectional view that schematically shows an example of laminated glass that uses the interlayer film for laminated glass shown in FIG. [Figure 12] FIG. 12 is a diagram schematically illustrating an example of an interlayer film for laminated glass that is not included in the interlayer film for laminated glass according to the present invention. [Figure 13] FIG. 13 is a diagram for explaining a method for preparing a test sample for a foaming test. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in detail below.

[0030] (Interlayer film for laminated glass) The interlayer film for laminated glass according to the present invention (sometimes abbreviated as "interlayer film" in this specification) is used in laminated glass.

[0031] The interlayer film of the present invention has a single-layer structure or a two or more layer structure. The interlayer film of the present invention may have a single-layer structure or a two or more layer structure. The interlayer film of the present invention may have a two-layer structure, a two or more layer structure, a three-layer structure, or a three or more layer structure. The interlayer film of the present invention may have only a first layer. The interlayer film of the present invention may have a first layer and a second layer disposed on a first surface side of the first layer. The interlayer film of the present invention may have a first layer, a second layer disposed on a first surface side of the first layer, and a third layer disposed on a second surface side of the first layer. The interlayer film of the present invention may be a single-layer interlayer film or a multi-layer interlayer film. The structure of the interlayer film of the present invention may be partially different. For example, the interlayer film of the present invention may have a portion having a single-layer structure and a portion having a multi-layer structure.

[0032] The interlayer film according to the present invention contains a light stabilizer and an antioxidant.

[0033] The interlayer film according to the present invention has one end and another end opposite the one end that has a thickness greater than 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.

[0034] In the interlayer film according to the present invention, the increase in thickness is not constant from one end to the other end. The interlayer film according to the present invention is different from an interlayer film in which the increase in thickness is constant from one end to the other end. The interlayer film according to the present invention is an interlayer film that contains a light stabilizer and an antioxidant and has one end and another end opposite the one end that is thicker than the one end (however, this excludes interlayer films in which the increase in thickness is constant from one end to the other end).

[0035] The interlayer film according to the present invention has the above-described configuration, and therefore can suppress the occurrence of voids in the interlayer film at the edges of the laminated glass, even when the interlayer film does not increase in thickness uniformly from one end to the other. The interlayer film according to the present invention contains a light stabilizer and an antioxidant, and therefore can effectively suppress deterioration of the interlayer film, particularly at the edges of the interlayer film, and as a result, can suppress the occurrence of voids.

[0036] In the interlayer film according to the present invention, there is a portion where the amount of increase in thickness varies from one end to the other end. Examples of interlayer films where the amount of increase in thickness is not constant from one end to the other end include interlayer films having at least one of the following configurations (1) to (3). The interlayer film preferably has at least one of the following configurations (1) to (3).

[0037] Configuration (1): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and within the region in which the thickness increases, there is a portion in which the amount of increase in thickness varies from the one end side to the other end side.

[0038] Configuration (2): The intermediate film has, in a region where the cross section in the thickness direction is wedge-shaped, a portion where the wedge angle varies from the one end side to the other end side.

[0039] Configuration (3): The interlayer film has a portion whose cross section in the thickness direction is rectangular and a portion whose cross section in the thickness direction is wedge-shaped.

[0040] Examples of interlayer films whose thickness does not increase uniformly from one end to the other include interlayer films having at least one of the following structures (i) to (vii): Structure (1) includes the following structures (i), (ii), and (iii); Structure (2) includes the following structures (iv), (v), and (vi). The interlayer film preferably has at least one of the following structures (i) to (vii):

[0041] Configuration (i): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and within the region in which the thickness increases, there is a portion in which the amount of increase in thickness becomes greater from the one end side to the other end side.

[0042] Configuration (ii): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and within the region in which the thickness increases, there is a portion in which the amount of increase in thickness decreases from the one end side to the other end side.

[0043] Configuration (iii): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and the region in which the thickness increases has a first portion in which the amount of increase in thickness is constant from the one end side to the other end side, and a second portion in which the amount of increase in thickness is constant from the one end side to the other end side. The amount of increase in thickness in the first portion is different from the amount of increase in thickness in the second portion.

[0044] Configuration (iv): The intermediate film has, in a region having a wedge-shaped cross section in the thickness direction, a portion where the wedge angle increases from the one end side to the other end side.

[0045] Configuration (v): The intermediate film has, in a region having a wedge-shaped cross section in the thickness direction, a portion where the wedge angle decreases from the one end side to the other end side.

[0046] Structure (vi): The interlayer film has a first region having a wedge-shaped cross-sectional shape in the thickness direction and a second region having a wedge-shaped cross-sectional shape in the thickness direction, and the wedge angle in the first region is different from the wedge angle in the second region.

[0047] Feature (vii): The interlayer film has a portion whose cross section in the thickness direction is rectangular and a portion whose cross section in the thickness direction is wedge-shaped.

[0048] The interlayer film may have only one of the structures (i) to (vii), or may have two, two or more, or three or more. The interlayer film may have at least the structure (i), or may have at least the structure (ii), or may have at least the structure (iii). The interlayer film may have at least the structure (iv), or may have at least the structure (v), or may have at least the structure (vi). The interlayer film may have at least the structure (vii). The interlayer film may have at least the structures (i) and (ii), or may have at least the structures (iv) and (v). The interlayer film may have at least the structure (i) and the structure (iv), or may have at least the structure (ii) and the structure (v), or may have at least the structure (iii) and the structure (vi). The interlayer film may have at least the structure (i) and the structure (vii), or may have at least the structure (ii) and the structure (vii), or may have at least the structure (iii) and the structure (vii). The interlayer film may have at least the structure (iv) and the structure (vii), or may have at least the structure (v) and the structure (vii), or may have at least the structure (vi) and the structure (vii).

[0049] The interlayer film may also have a configuration other than the configurations (i) to (vii).

[0050] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0051] Fig. 1 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a first embodiment of the present invention. Fig. 1 shows a cross section in the thickness direction of an interlayer film 11. 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 sake of convenience of illustration.

[0052] 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 thereto. The third layer 3 is disposed on a second surface side opposite the first surface of the first layer 1 and laminated thereto. 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. The interlayer film 11 has a three-layer structure.

[0053] 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 opposite ends. 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.

[0054] The interlayer film 11 has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the interlayer film 11 has a portion where the amount of increase in thickness increases from one end 11a to the other end 11b. The interlayer film 11 also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the interlayer film 11 has a portion where the wedge angle increases from one end 11a to the other end 11b.

[0055] The interlayer film may be a single-layer interlayer film having a one-layer structure, an interlayer film having a two-layer structure, or an interlayer film having a four-layer or more layer structure, as shown in Fig. 1. The interlayer film may also be in the shape shown in Fig. 1, with the cross section of the first layer in the thickness direction being wedge-shaped.

[0056] 2 is a cross-sectional view schematically illustrating an interlayer film for laminated glass according to a second embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11A.

[0057] The interlayer film 11A includes a first layer 1A (interlayer), a second layer 2A (surface layer), and a third layer 3A (surface layer). The second layer 2A is disposed on a first surface side of the first layer 1A and stacked thereon. The third layer 3A is disposed on a second surface side opposite the first surface of the first layer 1A and stacked thereon. The first layer 1A is disposed and sandwiched between the second layer 2A and the third layer 3A. The interlayer film 11A is a multilayer interlayer film. The interlayer film 11A has a three-layer structure.

[0058] 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. The cross-sectional shape in the thickness direction of the second layer 2A is wedge-shaped. The cross-sectional shapes in the thickness direction of the first layer 1A and the third layer 3A are rectangular. The thickness of the second layer 2A is greater 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 11A is greater than the thickness of the one end 11a. Therefore, the intermediate film 11A has thin and thick regions.

[0059] The intermediate film 11A has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11A has a portion where the amount of increase in thickness increases 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. Within 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 increases from one end 11a to the other end 11b.

[0060] The interlayer film may be a single-layer interlayer film having a one-layer structure, an interlayer film having a two-layer structure, or an interlayer film having a four-layer or more layer structure, as shown in FIG. 2.

[0061] 3 is a cross-sectional view schematically showing 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.

[0062] The intermediate film 11B includes a first layer 1B. The intermediate film 11B has a structure of only the first layer 1B, and is a single-layer intermediate film.

[0063] The intermediate film 11B 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 11B is greater than the thickness of the one end 11a. Therefore, the intermediate film 11B has a thin region and a thick region.

[0064] The intermediate film 11B has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11B has a portion where the amount of increase in thickness increases 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. Within 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 increases from one end 11a to the other end 11b.

[0065] The intermediate film 11B and the first layer 1B have portions 11Ba and 1Ba whose cross-sectional shape in the thickness direction is rectangular, and portions 11Bb and 1Bb whose cross-sectional shape in the thickness direction is wedge-shaped.

[0066] The interlayer film may have the shape shown in FIG. 3 and may be an interlayer film having a two-layer structure, an interlayer film having a three-layer structure, or an interlayer film having a four-layer or more structure.

[0067] 4 is a cross-sectional view schematically illustrating 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.

[0068] The intermediate film 11C includes a first layer 1C (intermediate layer), a second layer 2C (surface layer), and a third layer 3C (surface layer). The intermediate film 11 and the intermediate film 11C differ in the amount of thickness increase in the region where the thickness increases.

[0069] The intermediate film 11C has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11C has a portion where the amount of 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. Within 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 11a to the other end 11b.

[0070] The interlayer film may be a single-layer interlayer film having a one-layer structure, an interlayer film having a two-layer structure, or an interlayer film having a four-layer or more layer structure, as shown in Fig. 4. The interlayer film may also be in the shape shown in Fig. 4, with the cross section of the first layer in the thickness direction being wedge-shaped.

[0071] 5 is a cross-sectional view schematically illustrating an interlayer film for laminated glass according to a fifth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11D.

[0072] The intermediate film 11D includes a first layer 1D (intermediate layer), a second layer 2D (surface layer), and a third layer 3D (surface layer). The intermediate film 11A and the intermediate film 11D differ in the amount of thickness increase in the region where the thickness increases.

[0073] The intermediate film 11D has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11D has a portion where the amount of increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11D also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11D has a portion where the wedge angle decreases from one end 11a to the other end 11b.

[0074] The interlayer film may be a single-layer interlayer film having a one-layer structure, an interlayer film having a two-layer structure, or an interlayer film having a four-layer or more layer structure, as shown in FIG. 5.

[0075] 6 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a sixth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11E.

[0076] The intermediate film 11E includes a first layer 1E. The intermediate film 11B and the intermediate film 11E differ in the amount of increase in thickness in the region where the thickness increases.

[0077] The intermediate film 11E has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11E has a portion where the amount of increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11E also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11E has a portion where the wedge angle decreases from one end 11a to the other end 11b.

[0078] The intermediate film 11E and the first layer 1E have portions 11Ea, 1Ea whose cross-sectional shape in the thickness direction is rectangular, and portions 11Eb, 1Eb whose cross-sectional shape in the thickness direction is wedge-shaped.

[0079] The interlayer film may have a two-layer structure, a three-layer structure, or a four-layer or more layer structure, as shown in FIG. 6.

[0080] 7 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a seventh embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11F.

[0081] The intermediate film 11F includes a first layer 1F. The intermediate film 11B and the intermediate film 11F differ in the amount of increase in thickness in the region where the thickness increases.

[0082] The intermediate film 11F 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 uniform from one end 11a to the other end 11b.

[0083] The intermediate film 11F and the first layer 1F have portions 11Fa, 1Fa whose cross-sectional shape in the thickness direction is rectangular and portions 11Fb, 1Fb whose cross-sectional shape in the thickness direction is wedge-shaped. The portions 11Fa, 1Fa whose cross-sectional shape in the thickness direction is rectangular and the portions 11Fb, 1Fb whose cross-sectional shape in the thickness direction is wedge-shaped have different thickness increases, so the thickness increase of the intermediate film 11F is not constant from one end 11a to the other end 11b.

[0084] The intermediate film may have the shape shown in FIG. 7 and may be an intermediate film having a two-layer structure, an intermediate film having a three-layer structure, or an intermediate film having a four-layer or more structure.

[0085] 8 is a cross-sectional view schematically showing an interlayer film for laminated glass according to an eighth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11G.

[0086] The intermediate film 11G includes a first layer 1G (intermediate layer), a second layer 2G (surface layer), and a third layer 3G (surface layer). The intermediate film 11 and the intermediate film 11G have different thickness increases in the regions where the thickness increases.

[0087] The intermediate film 11G has a region where the thickness increases from one end 11a to the other end 11b. Within the region where the thickness increases, the intermediate film 11G has a portion where the amount of increase in thickness increases from one end 11a to the other end 11b and a portion where the amount of increase in thickness decreases. The intermediate film 11G also has a region where the cross-sectional shape in the thickness direction is wedge-shaped. Within the region where the cross-sectional shape in the thickness direction is wedge-shaped, the intermediate film 11G has a portion where the wedge angle increases from one end 11a to the other end 11b and a portion where the wedge angle decreases.

[0088] The interlayer film may be a single-layer interlayer film having a one-layer structure, an interlayer film having a two-layer structure, or an interlayer film having a four-layer or more layer structure, as shown in Fig. 8. The interlayer film may also be shaped as shown in Fig. 8, with the cross section of the first layer in the thickness direction being wedge-shaped.

[0089] 9 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a ninth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11H.

[0090] The intermediate film 11H includes a first layer 1H (intermediate layer), a second layer 2H (surface layer), and a third layer 3H (surface layer).

[0091] The intermediate film 11H 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. The cross-sectional shape in the thickness direction of the second layer 2H and the third layer 3H is wedge-shaped. The cross-sectional shape in the thickness direction of the first layer 1H is rectangular. The thickness of the second layer 2H and the third layer 3H is greater 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 11H is greater than the thickness of the one end 11a. Therefore, the intermediate film 11H has a thin region and a thick region.

[0092] The intermediate film 11H has a region in which the thickness increases from one end 11a to the other end 11b. Within the region in which the thickness increases, the intermediate film 11H includes a first portion 11Ha, which has a constant increase in thickness, and a second portion 11Hb, which also has a constant increase in thickness. The increase in thickness in the first portion 11Ha is different from the increase in thickness in the second portion 11Hb. The increase in thickness in the first portion 11Ha is smaller than the increase in thickness in the second portion 11Hb. Because the increase in thickness in the first portion 11Ha is different from the increase in thickness in the second portion 11Hb, the increase in thickness of the intermediate film 11H is not constant from the one end 11a to the other end 11b. The intermediate film 11H also has a first region having a wedge-shaped cross-section in the thickness direction and a second region having a wedge-shaped cross-section in the thickness direction. The wedge angle in the first region is different from the wedge angle in the second region. The wedge angle in the first region is smaller than the wedge angle in the second region.

[0093] The intermediate film may be a single-layer intermediate film having a one-layer structure, such as the shape shown in Figure 9, an intermediate film having a two-layer structure, or an intermediate film having a four-layer or more structure.

[0094] Fig. 10 is a cross-sectional view schematically showing an interlayer film for laminated glass according to a tenth embodiment of the present invention, showing a cross section in the thickness direction of an interlayer film 11I.

[0095] The intermediate film 11I includes a first layer 1I (intermediate layer), a second layer 2I (surface layer), and a third layer 3I (surface layer).

[0096] The intermediate film 11I 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. The cross-sectional shape in the thickness direction of the second layer 2I and the third layer 3I is wedge-shaped. The cross-sectional shape in the thickness direction of the first layer 1I is rectangular. The second layer 2I and the third layer 3I 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 11I is thicker than the thickness of the one end 11a. Therefore, the intermediate film 11I has a thin region and a thick region.

[0097] The intermediate film 11I has a region where the thickness increases from one end 11a to the other end 11b. The intermediate film 11H has, within the region where the thickness increases, a portion where the increase in thickness decreases from one end 11a to the other end 11b. The intermediate film 11I also has a region where the cross section in the thickness direction is wedge-shaped. The intermediate film 11I has, within the region where the cross section in the thickness direction is wedge-shaped, a portion where the wedge angle decreases from one end 11a to the other end 11b.

[0098] The intermediate film 11I has a portion 11Ia whose cross-section in the thickness direction is rectangular and a portion 11Ib whose cross-section in the thickness direction is wedge-shaped. The second layer 2I and the third layer 3I each have a portion whose cross-section in the thickness direction is rectangular and a portion whose cross-section in the thickness direction is wedge-shaped. Because the amount of increase in thickness differs between the portion 11Ia whose cross-section in the thickness direction is rectangular and the portion 11Ib whose cross-section in the thickness direction is wedge-shaped, the amount of increase in thickness of the intermediate film 11I is not constant from one end 11a to the other end 11b.

[0099] The intermediate film may be a single-layer intermediate film having a one-layer structure, such as the shape shown in FIG. 10, an intermediate film having a two-layer structure, or an intermediate film having a four-layer or more structure.

[0100] For reference, an interlayer film that is not included in the interlayer film according to the present invention is shown in FIG.

[0101] In the wedge-shaped intermediate film 101 shown in FIG. 12, the amount of increase in thickness is constant from one end 101a to the other end 101b.

[0102] The distance between one end and the other end of the interlayer film is defined as L. Preferably, the interlayer film has a minimum thickness in a region from 0L to 0.4L from one end to the other end, and a maximum thickness in a region from 0L to 0.4L from the other end to the one end. More preferably, the interlayer film has a minimum thickness in a region from 0L to 0.3L from one end to the other end, and a maximum thickness in a region from 0L to 0.3L from the other end to the one end. It is even more preferable that the interlayer film has a minimum thickness in a region from 0L to 0.2L from one end to the other end, and a maximum thickness in a region from 0L to 0.2L from the other end to the one end. It is even more preferable that the interlayer film has a minimum thickness in a region from 0L to 0.1L from one end to the other end, and a maximum thickness in a region from 0L to 0.1L from the other end to the one end. It is particularly preferred that the interlayer has a minimum thickness at one end and a maximum thickness at the other end.

[0103] The distance L between one end and the other end of the interlayer is preferably 3 m or less, more preferably 2 m or less, particularly preferably 1.5 m or less, and is preferably 0.5 m or more, more preferably 0.8 m or more, particularly preferably 1 m or more.

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

[0105] From the viewpoint of practical use and 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.

[0106] From the viewpoint of practicality and 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.

[0107] The interlayer film is used, for example, in laminated glass for a head-up display (HUD). The interlayer film is preferably an interlayer film for a head-up display. When the interlayer film is used in laminated glass for a head-up display, the interlayer film has a display-compatible area that corresponds to the display area of ​​the head-up display. The display-compatible area is an area in which information can be displayed well.

[0108] To prevent 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.

[0109] The wedge angle θ of the interlayer film is the interior angle at the intersection of a line connecting the surface portion (first surface portion) on one side of the interlayer film between the maximum and minimum thickness portions of the interlayer film and a line connecting the surface portion (second surface portion) on the other side of the interlayer film between the maximum and minimum thickness portions of the interlayer film.

[0110] In addition, when there are multiple maximum thickness portions, when there are multiple minimum thickness portions, when the maximum thickness portion is in a fixed region, or when the minimum thickness portion is in a fixed region, the maximum thickness portion and the minimum thickness portion for determining the wedge angle θ are selected so that the wedge angle θ to be determined is largest.

[0111] To more effectively suppress ghosting, the wedge angle θ of the interlayer film is preferably 0.05 mrad (0.00288 degrees) or greater, more preferably 0.1 mrad (0.00575 degrees) or greater, and even more preferably 0.2 mrad (0.0115 degrees) or greater. Furthermore, when the wedge angle θ is equal to or greater than the lower limit, a laminated glass suitable for vehicles with a large windshield installation angle, such as trucks and buses, can be obtained.

[0112] To more effectively suppress ghosting, the wedge angle θ of the interlayer film is preferably 2 mrad (0.1146 degrees) or less, and more preferably 0.7 mrad (0.0401 degrees) or less. Furthermore, when the wedge angle θ is equal to or less than the upper limit, a laminated glass suitable for vehicles with a small windshield installation angle, such as sports cars, can be obtained.

[0113] The wedge angle (θ) of the interlayer film and the thickness of the interlayer film can be measured using a contact thickness measuring instrument "TOF-4R" (manufactured by Yamabun Denki Co., Ltd.).

[0114] 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 from one end to the other end over the shortest distance.

[0115] An example of a measuring device that can be used to measure the wedge angle (θ) and thickness of the interlayer film after it has been formed into laminated glass is 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 laminated glass state.

[0116] From the viewpoint of suppressing double images more effectively, it is preferable that the intermediate film has the display corresponding area in the region from a position 6 cm from one end of the intermediate film toward the other end to a position 63.8 cm from the one end toward the other end.

[0117] From the viewpoint of suppressing double images more effectively, it is more preferable that the intermediate film has the display corresponding area in the region from a position 8 cm from one end of the intermediate film toward the other end to a position 61.8 cm from the one end toward the other end.

[0118] From the viewpoint of suppressing double images even more effectively, it is even more preferable that the intermediate film has the display corresponding area in a region from a position 9 cm from one end of the intermediate film toward the other end to a position 60.8 cm from the one end toward the other end.

[0119] From the viewpoint of suppressing double images more effectively, it is particularly preferable that the intermediate film has the display corresponding area in the region from a position 9.5 cm from one end of the intermediate film toward the other end to a position 60.3 cm from the one end toward the other end.

[0120] From the viewpoint of suppressing double images more effectively, it is most preferable that the intermediate film have the display corresponding area in the region from a position 10 cm from one end of the intermediate film toward the other end to a position 59.8 cm from the one end toward the other end.

[0121] The display-corresponding area may be present in a part or the entire area from the one end of the interlayer film to the position (e.g., 63.8 cm) from the one end toward the other end. The display-corresponding area may be approximately 30 cm in size in the direction connecting the one end and the other end.

[0122] From the viewpoint of effectively suppressing double images, it is preferable that the intermediate film has a portion whose cross-sectional shape in the thickness direction is wedge-shaped in the region from a position 6 cm from one end of the intermediate film toward the other end to a position 63.8 cm from the one end toward the other end.

[0123] From the viewpoint of effectively suppressing double images, it is preferable that the intermediate film has a portion whose cross-sectional shape in the thickness direction is wedge-shaped in the region from a position 8 cm from one end of the intermediate film toward the other end to a position 61.8 cm from the one end toward the other end.

[0124] From the viewpoint of effectively suppressing double images, it is further preferable that the intermediate film has a portion whose cross-sectional shape in the thickness direction is wedge-shaped in the region from a position 9 cm from one end of the intermediate film toward the other end to a position 60.8 cm from the one end toward the other end.

[0125] From the viewpoint of effectively suppressing double images, it is particularly preferable that the intermediate film has a portion whose cross-sectional shape in the thickness direction is wedge-shaped in the region from a position 9.5 cm from one end of the intermediate film toward the other end to a position 60.3 cm from the one end toward the other end.

[0126] From the viewpoint of effectively suppressing double images, it is most preferable that the intermediate film has a portion whose cross-sectional shape in the thickness direction is wedge-shaped in the region from a position 10 cm from one end of the intermediate film toward the other end to a position 59.8 cm from the one end toward the other end.

[0127] The portion having a wedge-shaped cross section in the thickness direction may be present in part or the entire area from the one end to the other end to the position (e.g., 63.8 cm). The portion having a wedge-shaped cross section in the thickness direction may be present over a length of about 30 cm in the direction connecting the one end and the other end.

[0128] The interlayer film may have a shade area. The shade area may be separated from the display-corresponding area. The shade area is provided, for example, for the purpose of preventing the driver from feeling dazzled by sunlight or outdoor lighting while driving. The shade area may also be provided to provide heat insulation. The shade area is preferably located at the edge of the interlayer film. The shade area is preferably strip-shaped.

[0129] In the shaded region, a colorant or filler may be used to change the color and visible light transmittance. The colorant or filler may be contained in only a portion of the interlayer film thickness, or may be contained in the entire interlayer film thickness.

[0130] From the viewpoint of improving the display quality and widening the field of view, the visible light transmittance of the display-corresponding area is preferably 70% or more, more preferably 80% or more, even more preferably 88% or more, and particularly 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.

[0131] For example, when the visible light transmittance varies between the display corresponding area and the shade area of ​​the interlayer film, the visible light transmittance is measured at the center position of the display corresponding area and the center position of the shade area.

[0132] The visible light transmittance of the obtained laminated glass at a wavelength 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.

[0133] The display-corresponding region preferably has a length direction and a width direction. In order to provide excellent versatility for the interlayer film, 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.

[0134] 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 opposite sides of the TD direction.

[0135] Materials that can be used for the interlayer film according to the present invention will be described in detail below.

[0136] (light stabilizer) The interlayer film contains a light stabilizer. The first layer preferably contains a light stabilizer. The second layer preferably contains a light stabilizer. The third layer preferably contains a light stabilizer. By using the light stabilizer, deterioration of the resin can be effectively suppressed, and the effects of the present invention can be effectively exhibited. Furthermore, by using the light stabilizer, the visible light transmittance is further prevented from decreasing. The light stabilizers may be used alone or in combination of two or more.

[0137] From the viewpoint of more effectively exerting the effects of the present invention, the light stabilizer is preferably a light stabilizer in which a carbon atom, a hydrogen atom, or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure, and more preferably a light stabilizer in which a carbon atom or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure.The light stabilizer is preferably a light stabilizer in which a carbon atom is bonded to a nitrogen atom of a piperidine structure, and also preferably a light stabilizer in which an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure.

[0138] From the viewpoint of further effectively exerting the effects of the present invention, the light stabilizer is more preferably a hindered amine light stabilizer, such as a hindered amine light stabilizer in which a carbon atom, a hydrogen atom, or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure.

[0139] From the viewpoint of exerting the effects of the present invention more effectively, the hindered amine light stabilizer is preferably a hindered amine light stabilizer in which a carbon atom, a hydrogen atom, or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure. From the viewpoint of exerting the effects of the present invention even more effectively, the hindered amine light stabilizer is more preferably a hindered amine light stabilizer in which a carbon atom or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure. The hindered amine light stabilizer is preferably a hindered amine light stabilizer in which a carbon atom is bonded to a nitrogen atom of a piperidine structure, and is also preferably a hindered amine light stabilizer in which an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure.

[0140] In the light stabilizer having a carbon atom bonded to the nitrogen atom of the piperidine structure, the carbon atom bonded to the nitrogen atom of the piperidine structure is preferably a carbon atom of an alkyl group or alkylene group bonded to the nitrogen atom of the piperidine structure.

[0141] Examples of the hindered amine light stabilizer in which a carbon atom is bonded to the nitrogen atom of the piperidine structure include "Tinuvin 765" and "Tinuvin 622SF" manufactured by BASF, and "ADEKA STAB LA-52" manufactured by ADEKA.

[0142] Examples of the hindered amine light stabilizer in which an alkoxy group is bonded to the nitrogen atom of the piperidine structure include "TinuvinXT-850FF" and "TinuvinXT-855FF" manufactured by BASF, and "ADEKA STAB LA-81" manufactured by ADEKA.

[0143] Examples of the hindered amine light stabilizer in which a hydrogen atom is bonded to the nitrogen atom of the piperidine structure include "Tinuvin 770DF" manufactured by BASF and "Hostavin N24" manufactured by Clariant.

[0144] In order to more effectively exert the effects of the present invention, the molecular weight of the light stabilizer is preferably 2,000 or less, more preferably 1,000 or less, and even more preferably 700 or less.

[0145] The interlayer film preferably has a distribution in the weight-basis content of the light stabilizer in the direction connecting one end and the other end, such that the weight-basis content of the light stabilizer is higher on the other end side in the direction connecting the one end and the other end. The interlayer film preferably has a region where the weight-basis content of the light stabilizer is lower than the weight-basis content of the light stabilizer on the other end side in the direction connecting the one end and the other end. The interlayer film preferably has a distribution in the weight-basis content of the light stabilizer in the direction connecting the one end and the other end, such that the weight-basis content of the light stabilizer on the other end side in the direction connecting the one end and the other end is higher than the weight-basis content of the light stabilizer on the one end side in the direction connecting the one end and the other end. The interlayer film preferably has a distribution in the weight-based content of the light stabilizer in the direction connecting one end and the other end, such that the weight-based content of the light stabilizer at the other end is higher than the weight-based content of the light stabilizer in the center of the direction connecting the one end and the other end. When the distance between one end and the other end of the interlayer film is L, the interlayer film preferably has a distribution in the weight-based content of the light stabilizer in the direction connecting the one end and the other end, such that the weight-based content of the light stabilizer is higher in a region 0.05L from the other end toward the inside. The interlayer film preferably has a distribution in the weight-based content of the light stabilizer in the direction connecting the one end and the other end, such that the weight-based content of the light stabilizer in a region 0.05L from the other end toward the inside is higher than the weight-based content of the light stabilizer in a region 0.05L from the one end toward the inside. The interlayer film preferably has a distribution in the weight-based content of the light stabilizer in a region of 0.05 L extending inward from the other end so that the weight-based content of the light stabilizer in a region of 0.05 L in the direction connecting the one end and the other end is greater than the weight-based content of the light stabilizer in a central region of 0.05 L in the direction connecting the one end and the other end. In laminated glass obtained using an interlayer film whose thickness does not increase uniformly from one end to the other end, stress is particularly likely to occur on the other end side, and therefore voids are likely to occur in the interlayer film on the other end side.When the light stabilizer is present with the above distribution, the generation of voids on the other end side can be more effectively suppressed.

[0146] The content of the light stabilizer in 100% by weight of the interlayer film is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and is preferably 0.5% by weight or less, more preferably 0.3% by weight or less. When the content of the light stabilizer is equal to or more than the above lower limit and equal to or less than the above upper limit, the effects of the present invention can be more effectively exhibited.

[0147] The content of the light stabilizer in 100% by weight of the layer (first layer, second layer, or third layer) containing the light stabilizer is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and preferably 0.5% by weight or less, more preferably 0.3% by weight or less. When the content of the light stabilizer is equal to or more than the above lower limit and equal to or less than the above upper limit, the effects of the present invention can be more effectively exhibited.

[0148] (antioxidant) The interlayer film contains an antioxidant. The first layer preferably contains an antioxidant. The second layer preferably contains an antioxidant. The third layer preferably contains an antioxidant. By using the antioxidant, deterioration of the resin can be effectively suppressed, and the effects of the present invention can be effectively exhibited. Furthermore, by using the antioxidant, the visible light transmittance is further prevented from decreasing. The antioxidants may be used alone or in combination of two or more.

[0149] In order to more effectively exert the effects of the present invention, the first layer preferably contains a light stabilizer and an antioxidant.

[0150] Examples of the antioxidant 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.

[0151] From the viewpoint of more effectively exerting the effects of the present invention, the antioxidant is preferably a phenol-based antioxidant or a phosphorus-based antioxidant, and more preferably a phenol-based antioxidant.

[0152] Examples of the phenolic antioxidant include 2,6-di-t-butyl-p-cresol (BHT), butylhydroxyanisole (BHA), 2,6-di-t-butyl-4-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis-(4-methyl-6-butylphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), 4,4'-butylidene-bis-(3-methyl-6-t-butylphenol), 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-methylbenzenepropanoate)ethylenebis(oxyethylene). One or more of these antioxidants are preferably used.

[0153] 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.

[0154] In order to more effectively exert the effects of the present invention, the molecular weight of the antioxidant is preferably 220 or more, more preferably 250 or more, and preferably 1,000 or less.

[0155] Commercially available antioxidants include, for example, "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.

[0156] The interlayer film preferably has a distribution in the weight-based content of the antioxidant in the direction connecting one end and the other end such that the weight-based content of the antioxidant is higher on the other end side in the direction connecting the one end and the other end. The interlayer film preferably has a region where the weight-based content of the antioxidant is lower than the weight-based content of the antioxidant on the other end side in the direction connecting the one end and the other end. The interlayer film preferably has a distribution in the weight-based content of the antioxidant in the direction connecting the one end and the other end such that the weight-based content of the antioxidant on the other end side in the direction connecting the one end and the other end is higher than the weight-based content of the antioxidant on the one end side in the direction connecting the one end and the other end. The interlayer film preferably has a distribution in the weight-based content of the antioxidant in the direction connecting one end and the other end, such that the weight-based content of the antioxidant on the other end side in the direction connecting the one end and the other end is higher than the weight-based content of the antioxidant in the center in the direction connecting the one end and the other end. When the distance between one end and the other end of the interlayer film is L, the interlayer film preferably has a distribution in the weight-based content of the antioxidant in the direction connecting the one end and the other end, such that the weight-based content of the antioxidant is higher in a region 0.05 L from the other end toward the inside. The interlayer film preferably has a distribution in the weight-based content of the antioxidant in the direction connecting the one end and the other end, such that the weight-based content of the antioxidant in a region 0.05 L from the other end toward the inside is higher than the weight-based content of the antioxidant in a region 0.05 L from the one end toward the inside. The intermediate film preferably has a distribution in the weight content of the antioxidant in the direction connecting the one end and the other end such that the weight content of the antioxidant in a region of 0.05 L extending inward from the other end is greater than the weight content of the antioxidant in a central region of 0.05 L in the direction connecting the one end and the other end.In laminated glass obtained using an interlayer film whose thickness does not increase uniformly from one end to the other, stress is particularly likely to occur at the other end, and therefore voids are likely to form in the interlayer film at the other end. By having the antioxidant distribution as described above, the formation of voids at the other end can be more effectively suppressed.

[0157] The content of the antioxidant in 100% by weight of the interlayer film is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and is preferably 2% by weight or less, more preferably 1.8% by weight or less. When the content of the antioxidant is equal to or more than the above lower limit and equal to or less than the above upper limit, the effects of the present invention can be more effectively exhibited, and a high visible light transmittance can be maintained for a long period of time.

[0158] The content of the antioxidant in 100% by weight of the layer (first layer, second layer, or third layer) containing the antioxidant is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and preferably 2% by weight or less, more preferably 1.8% by weight or less. When the content of the antioxidant is equal to or more than the above lower limit and equal to or less than the above upper limit, the effects of the present invention can be more effectively exhibited, and a high visible light transmittance can be maintained for a long period of time.

[0159] (thermoplastic resin) The interlayer preferably contains a resin (hereinafter may be referred to as resin (0)). The interlayer preferably contains a thermoplastic resin (hereinafter may be referred to as thermoplastic resin (0)). The interlayer 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 resin (hereinafter may be referred to as resin (1)). 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 resin (hereinafter may be referred to as resin (2)). 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 resin (hereinafter may be referred to as resin (3)). 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 resins (1), (2), and (3) may be the same or different. Since sound insulation is further improved, it is preferable that the resin (1) is different from the resins (2) and (3). The thermoplastic resins (1), (2), and (3) may be the same or different. Since sound insulation is further improved, it is preferable that the thermoplastic resin (1) is 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, it is preferable that the polyvinyl acetal resin (1) is 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.

[0160] Examples of the thermoplastic resin include polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, polyurethane resin, ionomer resin, polyvinyl alcohol resin, etc. Thermoplastic resins other than these may also be used.

[0161] 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 mol% to 99.9 mol%.

[0162] 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, and most preferably 2700 or more, and is preferably 5000 or less, more preferably 4000 or less, and even more preferably 3500 or less. When the average degree of polymerization is at least the lower limit, the penetration resistance of the laminated glass is further improved. When the average degree of polymerization is at most the upper limit, the interlayer film can be easily formed.

[0163] The average degree of polymerization of the polyvinyl alcohol is determined by a method in accordance with JIS K6726 "Testing method for polyvinyl alcohol."

[0164] 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. The number of carbon atoms in the acetal group in the polyvinyl acetal resin may be 4 or 5.

[0165] The aldehyde is not particularly limited. Generally, an aldehyde having 1 to 10 carbon atoms is suitably used. Examples of the aldehyde having 1 to 10 carbon atoms include propionaldehyde, n-butylaldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, and benzaldehyde. The aldehyde is preferably propionaldehyde, n-butylaldehyde, isobutyraldehyde, n-hexylaldehyde, or n-valeraldehyde, more preferably propionaldehyde, n-butylaldehyde, or isobutyraldehyde, and even more preferably n-butylaldehyde. The above aldehydes may be used alone or in combination of two or more.

[0166] 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 greater 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.

[0167] 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, and even more preferably 22 mol% or more. The hydroxyl group content (hydroxyl group amount) of the polyvinyl acetal resin (1) is preferably 30 mol% or less, more preferably 28 mol% or less, even more preferably 27 mol% or less, even more preferably 25 mol% or less, particularly preferably less than 25 mol%, and most preferably 24 mol% or less. When the hydroxyl group content is at least the lower limit, the mechanical strength of the interlayer film is further increased. In particular, when the hydroxyl group content of the polyvinyl acetal resin (1) is 20 mol% or more, the reaction efficiency is high and productivity is excellent, and when it is 28 mol% or less, the sound insulation of the laminated glass is further improved. Furthermore, when the hydroxyl group content is at most the upper limit or less, the flexibility of the interlayer film is increased, making it easier to handle.

[0168] The hydroxyl group content of each of the polyvinyl acetal resins (2) and (3) is preferably 25 mol% or more, more preferably 28 mol% or more, even more preferably 30 mol% or more, even more preferably more than 31 mol%, even more preferably 31.5 mol% or more, particularly preferably 32 mol% or more, and most preferably 33 mol% or more. The hydroxyl group content of each of the polyvinyl acetal resins (2) and (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 equal to or greater 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 the interlayer film easier to handle.

[0169] From the viewpoint of further improving sound insulation, the hydroxyl group content of the polyvinyl acetal resin (1) is preferably lower than the hydroxyl group content of the polyvinyl acetal resin (2). From the viewpoint of further improving sound insulation, the hydroxyl group content of the polyvinyl acetal resin (1) is preferably lower than the hydroxyl group content of the polyvinyl acetal resin (3). From the viewpoint of still further improving sound insulation, the absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (2) is preferably 1 mol % or more, more preferably 5 mol % or more, even more preferably 9 mol % or more, particularly preferably 10 mol % or more, and most preferably 12 mol % or more. From the viewpoint of further improving sound insulation, the absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (3) is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 9 mol% or more, particularly preferably 10 mol% or more, and most preferably 12 mol% or more. The absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (2) is preferably 20 mol% or less. The absolute value of the difference between the hydroxyl group content of the polyvinyl acetal resin (1) and the hydroxyl group content of the polyvinyl acetal resin (3) is preferably 20 mol% or less.

[0170] The hydroxyl group content of the polyvinyl acetal resin is the molar fraction calculated by dividing the number of ethylene groups having hydroxyl groups by the total number of ethylene groups in the main chain, and is expressed as a percentage. The number of ethylene groups having hydroxyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0171] 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 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 greater than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is improved. When the degree of acetylation is equal to or less than the upper limit, the moisture resistance of the interlayer film and laminated glass is improved.

[0172] 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 is 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 at least the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is improved. When the degree of acetylation is at most the upper limit, the moisture resistance of the interlayer film and laminated glass is improved. In particular, when the degree of acetylation of the polyvinyl acetal resin (1) is 0.1 mol% or more and 25 mol% or less, excellent penetration resistance is achieved.

[0173] The acetylation degree 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 acetylation degree is equal to or greater than the lower limit, the compatibility of the polyvinyl acetal resin with the plasticizer is improved. When the acetylation degree is equal to or less than the upper limit, the moisture resistance of the interlayer film and the laminated glass is improved.

[0174] The degree of acetylation is a molar fraction calculated by dividing the amount of ethylene groups having acetyl groups by the total amount of ethylene groups in the main chain, and is expressed as a percentage. The amount of ethylene groups having acetyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0175] 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 greater 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.

[0176] 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 greater 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.

[0177] 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 greater 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.

[0178] The degree of acetalization is determined as follows. First, 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 to determine the value. The obtained value is divided by the total amount of ethylene groups in the main chain to determine the molar fraction. The value expressed as a percentage of this molar fraction is the degree of acetalization.

[0179] The hydroxyl group content (hydroxyl group amount), acetalization degree (butyralization degree), and acetylation degree are preferably calculated from the results of measurements performed according to JIS K6728 "Testing Methods 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 of measurements performed according to JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0180] The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the interlayer film is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the interlayer film may be 100% by weight or less. The main component (50% by weight or more) of the thermoplastic resin in the interlayer film is preferably polyvinyl acetal resin.

[0181] The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the first layer is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the first layer may be 100% by weight or less. The main component (50% by weight or more) of the thermoplastic resin of the first layer is preferably polyvinyl acetal resin.

[0182] The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the second layer is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the second layer may be 100% by weight or less. The main component (50% by weight or more) of the thermoplastic resin in the second layer is preferably polyvinyl acetal resin.

[0183] The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the third layer is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The content of polyvinyl acetal resin in 100% by weight of the thermoplastic resin contained in the third layer may be 100% by weight or less. The main component (50% by weight or more) of the thermoplastic resin in the third layer is preferably polyvinyl acetal resin.

[0184] (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 the polyvinyl acetal resin preferably contains a plasticizer.

[0185] The plasticizer is not particularly limited. Conventionally known plasticizers can be used as the plasticizer. Only one type of plasticizer can be used, or two or more types can be used in combination.

[0186] Examples of the plasticizer include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, organic phosphate plasticizers, and organic phosphite plasticizers. The plasticizer is preferably an organic ester plasticizer. The plasticizer is preferably a liquid plasticizer.

[0187] Examples of the monobasic organic acid ester include glycol esters obtained by reacting glycol with a monobasic organic acid. Examples of the glycol include triethylene glycol, tetraethylene glycol, and tripropylene glycol. Examples of the monobasic organic acid include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octylic acid, 2-ethylhexyl acid, n-nonylic acid, decylic acid, and benzoic acid.

[0188] Examples of the polybasic organic acid ester include ester compounds of a polybasic organic acid and an alcohol having a linear or branched structure and having 4 to 8 carbon atoms. Examples of the polybasic organic acid include adipic acid, sebacic acid, and azelaic acid.

[0189] 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, and diethylene glycol di-2-ethylbutylene. Examples of suitable organic ester plasticizers include diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprylate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, 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 a phosphate ester and an adipate. Organic ester plasticizers other than those listed above may also be used as the organic ester plasticizer. Furthermore, adipic acid esters other than the above-mentioned adipic acid esters may also be used as the adipic acid ester.

[0190] Examples of the organic phosphoric acid plasticizer include tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

[0191] The plasticizer is preferably a diester plasticizer represented by the following formula (1):

[0192] [ka]

[0193] In the above formula (1), R1 and R2 each represent an organic group having 2 to 10 carbon atoms, R3 represents an ethylene group, an isopropylene group, or an n-propylene group, and p represents an integer of 3 to 10. In the above formula (1), R1 and R2 each preferably represent an organic group having 5 to 10 carbon atoms, and more preferably represent an organic group having 6 to 10 carbon atoms.

[0194] The plasticizer preferably includes triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), or triethylene glycol di-2-ethylpropanoate, more preferably triethylene glycol di-2-ethylhexanoate (3GO) or triethylene glycol di-2-ethylbutyrate (3GH), and even more preferably triethylene glycol di-2-ethylhexanoate (3GO).

[0195] The content of the plasticizer (0) relative to 100 parts by weight of the thermoplastic resin (0) in the interlayer film is defined as the content (0). The content (0) is preferably 5 parts by weight or more, more preferably 25 parts by weight or more, even more preferably 30 parts by weight or more, and preferably 100 parts by weight or less, more preferably 60 parts by weight or less, even more preferably 50 parts by weight or less. When the content (0) is at least the lower limit, the penetration resistance of the laminated glass is further improved. When the content (0) is at most the upper limit, the transparency of the interlayer film is further improved.

[0196] In the first layer, the content of the plasticizer (1) relative to 100 parts by weight of the thermoplastic resin (1) is defined as content (1). The content (1) is preferably 50 parts by weight or more, more preferably 55 parts by weight or more, and even more preferably 60 parts by weight or more. The content (1) 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 at least the lower limit, the flexibility of the interlayer film is increased, making the interlayer film easier to handle. When the content (1) is at most the upper limit, the penetration resistance of the laminated glass is further improved.

[0197] In the second layer, the content of the plasticizer (2) relative to 100 parts by weight of the thermoplastic resin (2) is defined as 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 content (3). The contents (2) and (3) are each preferably 5 parts by weight or more, more preferably 10 parts by weight or more, even 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 most preferably 25 parts by weight or more. The contents (2) and (3) are each preferably 45 parts by weight or less, more preferably 40 parts by weight or less, even more preferably 35 parts by weight or less, particularly preferably 32 parts by weight or less, and most preferably 30 parts by weight or less. When the contents (2) and (3) are equal to or greater than the lower limits, the flexibility of the interlayer film is increased, making the interlayer film easier to handle. 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 improved.

[0198] 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).

[0199] 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.

[0200] (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 heat-shielding material may be used, or two or more types may be used in combination.

[0201] 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.

[0202] 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 component X may be used, or two or more types may be used in combination.

[0203] There are no particular restrictions on the component X. As the component X, conventionally known phthalocyanine compounds, naphthalocyanine compounds, and anthracyanine compounds can be used.

[0204] Examples of the component X include phthalocyanine, phthalocyanine derivatives, naphthalocyanine, naphthalocyanine derivatives, anthracyanine, and anthracyanine derivatives. The phthalocyanine compound and the phthalocyanine derivative each preferably have a phthalocyanine skeleton. The naphthalocyanine compound and the naphthalocyanine derivative each preferably have a naphthalocyanine skeleton. The anthracyanine compound and the anthracyanine derivative each preferably have an anthracyanine skeleton.

[0205] From the viewpoint of further improving the heat-shielding 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.

[0206] From the viewpoint of effectively improving the heat-shielding properties and maintaining a higher visible light transmittance for a long period of time, the above-mentioned component X preferably contains a vanadium atom or a copper atom. The above-mentioned component X preferably contains a vanadium atom, and also preferably contains a copper atom. The above-mentioned component X is more preferably at least one of a phthalocyanine containing a vanadium atom or a copper atom, and a derivative of a phthalocyanine containing a vanadium atom or a copper atom. From the viewpoint of further improving the heat-shielding properties of the interlayer film and laminated glass, the above-mentioned component X preferably has a structural unit in which an oxygen atom is bonded to a vanadium atom.

[0207] The content of component X in 100 wt% of the interlayer film or in 100 wt% of the layer containing component X (the first, second, or third layer) is preferably 0.001 wt% or more, more preferably 0.005 wt% or more, even more preferably 0.01 wt% or more, and particularly preferably 0.02 wt% or more. The content of component X in 100 wt% of the interlayer film or in 100 wt% of the layer containing component X (the first, second, or third layer) is preferably 0.2 wt% or less, more preferably 0.1 wt% or less, even more preferably 0.05 wt% or less, and particularly preferably 0.04 wt% or less. When the content of component X is equal to or greater than the above-mentioned lower limit and equal to or less than the above-mentioned upper limit, the heat-shielding properties and visible light transmittance are sufficiently high. For example, a visible light transmittance of 70% or more is possible.

[0208] Heat-shielding particles: The interlayer 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. Use of the heat-shielding particles can effectively block infrared rays (heat rays). Only one type of the heat-shielding particles may be used, or two or more types may be used in combination.

[0209] From the viewpoint of further enhancing the heat-shielding properties of the laminated glass, the heat-shielding particles are more preferably metal oxide particles. The heat-shielding particles are preferably particles formed from a metal oxide (metal oxide particles).

[0210] Infrared rays, which have wavelengths longer than visible light (780 nm or longer), 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-mentioned heat-shielding particles, infrared rays (heat rays) can be effectively blocked. Heat-shielding particles refer to particles that can absorb infrared rays.

[0211] 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, 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. Other heat-shielding particles may also be used. The heat-shielding particles are preferably metal oxide particles because of their high heat-shielding function, and more preferably ATO particles, GZO particles, IZO particles, ITO particles, or tungsten oxide particles. In particular, the heat-shielding particles are preferably ITO particles or tungsten oxide particles because of their high heat-shielding function and ease of availability.

[0212] From the viewpoint of further improving the heat-shielding properties of the interlayer film and laminated glass, the tungsten oxide particles are preferably metal-doped tungsten oxide particles. The "tungsten oxide particles" include metal-doped tungsten oxide particles. 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.

[0213] From the viewpoint of further improving the heat-shielding properties of the interlayer film and laminated glass, cesium-doped tungsten oxide particles are particularly preferred. From the viewpoint of further improving the heat-shielding properties of the interlayer film and laminated glass, the cesium-doped tungsten oxide particles are represented by the formula: Cs 0.33 Tungsten oxide particles represented by WO3 are preferred.

[0214] The average particle size of the heat-shielding particles is preferably 0.01 μm or more, more preferably 0.02 μm or more, and preferably 0.1 μm or less, more preferably 0.05 μm or less. When the average particle size is equal to or greater than the lower limit, the heat ray shielding property is 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.

[0215] The "average particle size" refers to the volume-average particle size. The average particle size can be measured using a particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., "UPA-EX150") or the like.

[0216] The content of the heat-shielding particles (particularly the content of tungsten oxide particles) in 100 weight % of the interlayer film or 100 weight % of the layer containing the heat-shielding particles (first layer, second layer, or third layer) is preferably 0.01 weight % or more, more preferably 0.1 weight % or more, even more preferably 1 weight % or more, and particularly preferably 1.5 weight % or more. The content of the heat-shielding particles (particularly the content of tungsten oxide particles) in 100 weight % of the interlayer film or 100 weight % of the layer containing the heat-shielding particles (first layer, second layer, or third layer) is preferably 6 weight % or less, more preferably 5.5 weight % or less, even more preferably 4 weight % or less, particularly preferably 3.5 weight % or less, and most preferably 3 weight % or less. When the content of the heat-shielding particles is at least the above lower limit and at most the above upper limit, the heat shielding property is sufficiently high and the visible light transmittance is sufficiently high.

[0217] (metal salts) The interlayer film preferably contains at least one metal salt (hereinafter sometimes referred to as metal salt M) selected from alkali metal salts and alkaline earth metal salts. 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. Alkaline earth metals refer to six metals: 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.

[0218] 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.

[0219] Furthermore, alkali metal salts of organic acids having 2 to 16 carbon atoms and alkaline earth metal salts of organic acids having 2 to 16 carbon atoms can be used as the metal salt M. The metal salt M may include a magnesium salt of a carboxylic acid having 2 to 16 carbon atoms or a potassium salt of a carboxylic acid having 2 to 16 carbon atoms.

[0220] Examples of the magnesium salts of carboxylic acids having 2 to 16 carbon atoms and the potassium salts of carboxylic acids 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.

[0221] The total content of Mg and K in the interlayer film 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, and even more preferably 20 ppm or more, and is 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 at least the above lower limit and at most the above upper limit, the adhesion between the interlayer film and a laminated glass member such as a glass plate, or the adhesion between the layers in the interlayer film, can be more effectively controlled.

[0222] (UV screening agent) The interlayer film preferably contains an ultraviolet blocking agent. The first layer preferably contains an ultraviolet blocking agent. The second layer preferably contains an ultraviolet blocking agent. The third layer preferably contains an ultraviolet blocking agent. By using an ultraviolet blocking agent, the visible light transmittance of the interlayer film and laminated glass is more unlikely to decrease even after long-term use. Only one type of ultraviolet blocking agent may be used, or two or more types may be used in combination.

[0223] The ultraviolet screening agent includes an ultraviolet absorbing agent, and the ultraviolet screening agent is preferably an ultraviolet absorbing agent.

[0224] Examples of the ultraviolet screening agent include ultraviolet screening agents containing metal atoms, ultraviolet screening agents containing metal oxides, ultraviolet screening agents having a benzotriazole structure (benzotriazole compounds), ultraviolet screening agents having a benzophenone structure (benzophenone compounds), ultraviolet screening agents having a triazine structure (triazine compounds), ultraviolet screening agents having a malonic acid ester structure (malonic acid ester compounds), ultraviolet screening agents having an oxalic acid anilide structure (oxalic acid anilide compounds), and ultraviolet screening agents having a benzoate structure (benzoate compounds).

[0225] 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. The ultraviolet shielding agent is preferably not a heat-shielding particle.

[0226] The ultraviolet screening agent is preferably an ultraviolet screening agent having a benzotriazole structure, an ultraviolet screening agent having a benzophenone structure, an ultraviolet screening agent having a triazine structure, or an ultraviolet screening agent having a benzoate structure, more preferably an ultraviolet screening agent having a benzotriazole structure or an ultraviolet screening agent having a benzophenone structure, and even more preferably an ultraviolet screening agent having a benzotriazole structure.

[0227] Examples of the ultraviolet screening agent containing a metal oxide include zinc oxide, titanium oxide, and cerium oxide. Furthermore, the surface of the ultraviolet screening agent containing a metal oxide may be coated. Examples of the coating material for the surface of the ultraviolet screening agent containing a metal oxide include insulating metal oxides, hydrolyzable organosilicon compounds, and silicone compounds.

[0228] Examples of the insulating metal oxide include silica, alumina, zirconia, etc. The insulating metal oxide has a band gap energy of, for example, 5.0 eV or more.

[0229] Examples of the ultraviolet screening agent having a benzotriazole structure include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole ("Tinuvin P" manufactured by BASF), 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole ("Tinuvin 320" manufactured by BASF), 2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole ("Tinuvin 326" manufactured by BASF), and 2-(2'-hydroxy-3',5'-di-amylphenyl)benzotriazole ("Tinuvin 328" manufactured by BASF). Because of their excellent ultraviolet screening performance, the ultraviolet screening agent is preferably an ultraviolet screening agent having a benzotriazole structure containing a halogen atom, and more preferably an ultraviolet screening agent having a benzotriazole structure containing a chlorine atom.

[0230] Examples of the ultraviolet screening agent having a benzophenone structure include octabenzone ("Chimassorb 81" manufactured by BASF).

[0231] 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).

[0232] 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.

[0233] Commercially available UV screening agents having the malonic acid ester structure include Hostavin B-CAP, Hostavin PR-25, and Hostavin PR-31 (all manufactured by Clariant).

[0234] Examples of the ultraviolet screening agent having the 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).

[0235] 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).

[0236] The content of the ultraviolet screening agent and the content of the benzotriazole compound in 100% by weight of the interlayer film or 100% by weight of the layer containing the ultraviolet screening agent (first layer, second layer, or third layer) 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 this case, even after long-term use of the interlayer film and laminated glass, the visible light transmittance is even less likely to decrease. The content of the ultraviolet screening agent and the content of the benzotriazole compound in 100% by weight of the interlayer film or 100% by weight of the layer containing the ultraviolet screening agent (first layer, second layer, or third layer) 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. In particular, by ensuring that the content of the ultraviolet ray blocking agent is 0.2% by weight or more relative to 100% by weight of the layer containing the ultraviolet ray blocking agent, the visible light transmittance is even less likely to decrease even after long-term use of the interlayer film and laminated glass.

[0237] (Other ingredients) The interlayer film, the first layer, the second layer, and the third layer may each contain other components as necessary. The other components may include additives such as coupling agents, dispersants, surfactants, flame retardants, antistatic agents, adhesion modifiers other than metal salts, moisture-resistant agents, fluorescent brighteners, and infrared absorbers. These additives may be used alone or in combination of two or more.

[0238] (Other details of interlayer film for laminated glass) The interlayer film may be wound into a roll of the interlayer film. The roll may include a winding core and the interlayer film wound around the outer periphery of the winding core.

[0239] The method for producing the interlayer film is not particularly limited.

[0240] In view of excellent production efficiency of the interlayer film, it is preferable that the second layer and the third layer contain the same polyvinyl acetal resin. In view of excellent production efficiency of the interlayer film, it is more preferable that the second layer and the third layer contain the same polyvinyl acetal resin and the same plasticizer. In view of excellent production efficiency of the interlayer film, it is even more preferable that the second layer and the third layer are formed from the same resin composition.

[0241] The interlayer film preferably has an uneven shape on at least one of its two surfaces. The interlayer film more preferably has an uneven shape on both surfaces. The method for forming the uneven shape is not particularly limited, and examples thereof include lip embossing (melt fracture), embossing roll, calender roll, and profile extrusion.

[0242] (Laminated glass) The laminated glass of the present invention includes a first laminated glass member, a second laminated glass member, and the above-mentioned interlayer film for laminated glass. In the laminated glass of the present invention, the interlayer film for laminated glass is disposed between the first laminated glass member and the second laminated glass member.

[0243] FIG. 11 is a cross-sectional view that schematically shows an example of laminated glass that uses the interlayer film for laminated glass shown in FIG.

[0244] 11 includes a first laminated glass member 22, a second laminated glass member 23, and an interlayer film 11. The interlayer film 11 is disposed and sandwiched between the first laminated glass member 22 and the second laminated glass member 23.

[0245] The laminated glass is, for example, a head-up display. When the laminated glass is a head-up display, the laminated glass has a display area for the head-up display. The display area is an area where information can be displayed well.

[0246] The laminated glass is preferably a head-up display (HUD).

[0247] A head-up display system can be obtained 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 the 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.

[0248] The first laminated glass member is preferably a first glass plate, and the second laminated glass member is preferably a second glass plate.

[0249] Examples of the first and second laminated glass members include glass plates and PET (polyethylene terephthalate) films. The laminated glass includes not only laminated glass in which an interlayer film is sandwiched between two glass plates, but also laminated glass in which an interlayer film is sandwiched between a glass plate and a PET film or the like. The laminated glass is a laminate including glass plates, and preferably includes at least one glass plate. It is preferable that the first laminated glass member and the second laminated glass member are each a glass plate or a PET film, and that the laminated glass includes a glass plate as at least one of the first laminated glass member and the second laminated glass member. It is particularly preferable that both the first and second laminated glass members are glass plates.

[0250] Examples of the glass plate include inorganic glass and organic glass. Examples of the inorganic glass include float glass, heat-absorbing glass, heat-reflecting glass, polished glass, patterned glass, lined glass, and green glass. The organic glass is a synthetic resin glass that replaces inorganic glass. Examples of the organic glass include polycarbonate plates and poly(meth)acrylic resin plates. Examples of the poly(meth)acrylic resin plates include polymethyl(meth)acrylate plates.

[0251] The thickness of each of the first laminated glass member and the second laminated glass member is preferably 1 mm or more, preferably 5 mm or less, more preferably 3 mm or less. When the laminated glass member is a glass plate, the thickness of the glass plate is preferably 0.5 mm or more, more preferably 0.7 mm or more, and preferably 5 mm or less, more preferably 3 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.

[0252] The method for producing the laminated glass is not particularly limited. First, an interlayer film is sandwiched between the first laminated glass member and the second laminated glass member to obtain a laminate. Next, the air remaining between the first laminated glass member, the second laminated glass member, and the interlayer film is removed, for example, by passing the obtained laminate through a pressure roll or placing it in a rubber bag and suctioning it under reduced pressure. Thereafter, a pre-bonded laminate is obtained by pre-bonding at about 70°C to 110°C. Next, the pre-bonded laminate is placed in an autoclave or pressed at about 120°C to 150°C and a pressure of 1 MPa to 1.5 MPa to be bonded. In this manner, a laminated glass can be obtained.

[0253] The interlayer film and the laminated glass can be used in automobiles, railway vehicles, aircraft, ships, buildings, etc. The interlayer film and the laminated glass can also be used for applications other than these. The interlayer film and the laminated glass are preferably interlayer films and laminated glass for vehicles or buildings, and more preferably interlayer films and laminated glass for vehicles. The interlayer film and the laminated glass can be used for automobile windshields, side windows, rear windows, roof glass, backlight glass, etc. The interlayer film and the laminated glass are preferably used in automobiles. The interlayer film is preferably used to obtain laminated glass for automobiles.

[0254] 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.

[0255] The polyvinyl acetal resin used was acetalized using n-butylaldehyde, which has four carbon atoms. The degree of acetalization (degree of butyralization), degree of acetylation, and hydroxyl group content of the polyvinyl acetal resin were measured according to JIS K6728 "Testing Methods for Polyvinyl Butyral." Note that when measured according to ASTM D1396-92, the values ​​were similar to those obtained by the method according to JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0256] The following light stabilizers, antioxidants and ultraviolet screening agents were prepared.

[0257] (light stabilizer) Hindered amine light stabilizer (BASF, NC (alkyl group) type "Tinuvin 765", molecular weight 509)

[0258] (antioxidant) Phenolic antioxidant (BASF "IRGANOX 1010", molecular weight 1178) Phenolic antioxidant (2,6-di-t-butyl-p-cresol (BHT), molecular weight 220)

[0259] (UV screening agent) 2-(2'-hydroxy-3'-t-butyl-5-methylphenyl)-5-chlorobenzotriazole (BASF "Tinuvin 326")

[0260] Example 1 Preparation of resin composition for forming first layer: The following components were blended and thoroughly kneaded with a mixing roll to obtain a resin composition for forming the first layer.

[0261] Polyvinyl acetal resin (average polymerization degree 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 A light stabilizer in an amount to provide 0.025% by weight in the resulting first layer an antioxidant in an amount to provide 0.1% by weight in the resulting first layer; An ultraviolet screening agent in an amount that results in 0.2% by weight in the resulting first layer

[0262] Preparation of resin compositions for forming the second and third layers: The following components were blended and thoroughly kneaded with a mixing roll to obtain a resin composition for forming the second layer and the third layer.

[0263] 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) 40 parts by weight A Mg mixture (a 50:50 (weight ratio) mixture of magnesium 2-ethylbutyrate and magnesium acetate) in an amount that would result in a magnesium content of 60 ppm in the resulting interlayer film

[0264] Preparation of interlayer: The resin composition for forming the first layer and the resin compositions for forming the second and third layers were co-extruded using a co-extruder to obtain an interlayer film having a three-layer structure (second layer / first layer / third layer) (an interlayer film having the shape shown in Table 1).

[0265] Example 2 An interlayer film (having the shape shown in Table 1) was obtained in the same manner as in Example 1, except that the type and content of the antioxidant were changed as shown in Table 1.

[0266] (Comparative Example 1) An interlayer film (having the shape shown in Table 1) was obtained in the same manner as in Example 2, except that no light stabilizer was used.

[0267] (Comparative Example 2) An interlayer film (having the shape shown in Table 1) was obtained in the same manner as in Example 1, except that no light stabilizer was used.

[0268] Example 3 An interlayer film was obtained in the same manner as in Example 1, except that the configuration of the interlayer film was set as shown in Table 2. In Example 3, the same type of ultraviolet blocking agent as in Example 1 was blended in the same blending amount as in Example 1.

[0269] Example 4 An interlayer film (having the shape shown in Table 2) was obtained in the same manner as in Example 3, except that the type and content of the antioxidant were changed as shown in Table 2.

[0270] (Comparative Example 3) An interlayer film (having the shape shown in Table 2) was obtained in the same manner as in Example 4, except that no light stabilizer was used.

[0271] Comparative Example 4 An interlayer film (having the shape shown in Table 2) was obtained in the same manner as in Example 3, except that no light stabilizer was used.

[0272] Example 5 An interlayer film was obtained in the same manner as in Example 1, except that the configuration of the interlayer film was set as shown in Table 3. In Example 5, the same type of ultraviolet blocking agent as in Example 1 was blended in the same blending amount as in Example 1.

[0273] Example 6 An interlayer film (having the shape shown in Table 3) was obtained in the same manner as in Example 5, except that the type and content of the antioxidant were changed as shown in Table 3.

[0274] (Comparative Example 5) An interlayer film (having the shape shown in Table 3) was obtained in the same manner as in Example 6, except that no light stabilizer was used.

[0275] (Comparative Example 6) An interlayer film (having the shape shown in Table 3) was obtained in the same manner as in Example 5, except that no light stabilizer was used.

[0276] (Reference example A) An interlayer film with a constant increase in thickness from one end to the other was obtained in the same manner as in Example 1, except that the configuration of the interlayer film was set as shown in Table 3. In Reference Example A, the same type of ultraviolet blocking agent as in Example 1 was blended in the same blending amount as in Example 1.

[0277] (evaluation) (1) Partial wedge angle of the interlayer and wedge angle θ of the entire interlayer In the obtained interlayer film, points were selected at 2 mm intervals, starting from a position 4 cm from one end toward the other end and ending at a position 4 cm from the other end toward the one end, and the partial wedge angle was determined in each region every 80 mm in the direction connecting one end and the other end, with each point as the center.

[0278] Specifically, the partial wedge angle in each region was measured in the following order of 1 to 3.

[0279] 1: Select points P at 2 mm intervals, starting from one end of the intermediate film and ending at the other end. 2: At each of the points P, the thickness of the interlayer film is measured. 3: A linear line is obtained by the least squares method with the distance (unit: mm) from the end of the one end of the interlayer film as the x-axis and the thickness (unit: μm) of the interlayer film as the y-axis. The interior angle between the obtained linear line and the line y = 0 is defined as the partial wedge angle.

[0280] The table shows the ranges (upper and lower limits) of the obtained partial wedge angles.

[0281] Further, for the obtained interlayer film, the wedge angle θ of the entire interlayer film was determined.

[0282] (2) Distance at which voids occur (foaming test) The obtained interlayer film was sandwiched between two pieces of clear glass measuring 100 cm in length, 150 cm in width and 2.5 mm in thickness, and held at 90°C for 30 minutes in a vacuum laminator, followed by vacuum pressing to obtain laminated glass.

[0283] Fig. 13 is a diagram illustrating a method for producing a test sample for a foaming test. As shown in Fig. 13, one end of the obtained laminated glass 21X was cut out without changing the distance between the interlayer film 11X and the clear glass sheets 22X, 23X, i.e., while the clear glass sheets 22X, 23X were fixed so as not to deform, to obtain a test sample A for the foaming test, 15 cm long and 5 cm wide. The other end of the laminated glass 21X was similarly cut out to obtain a test sample B for the foaming test, 15 cm long and 5 cm wide.

[0284] The obtained test samples A and B for the foaming test were each exposed to an irradiation intensity of 60 W / m from one side of the clear glass surface while maintaining the clear glass in a state where no deformation occurred. 2 The specimens were irradiated with ultraviolet light of 1000 kJ / cm² at a temperature of 50°C for 2000 hours (JIS-UV test). After irradiation, the ends of foaming test specimens A and B were observed, and the distance at which voids were formed (void distance) was measured at one end of the interlayer film (foaming test specimen A) and the other end of the interlayer film (foaming test specimen B).

[0285] For interlayer films having the same shape, the degree to which the distance at which voids are formed is reduced is evaluated by calculating the percentage reduction in the gap distance, expressed by the following formula (X). The percentage reduction in the gap distance is an index that shows the degree to which the distance at which voids are formed is reduced in a comparison interlayer film compared to a comparison reference interlayer film for interlayer films having the same shape. The percentage reduction in the gap distance below was calculated using the test sample with the longer gap distance between test samples A and B for the foaming test.

[0286] Reduction rate of gap distance (%) = D1 / D2 × 100 (X) D1: Gap distance (mm) when using the comparative interlayer D2: Gap distance (mm) when using the reference interlayer

[0287] For Examples 1 and 2 and Comparative Examples 1 and 2, which had the same shape, the interlayer films obtained in Examples 1 and 2 and Comparative Example 2 were used as comparative interlayer films, and the interlayer film obtained in Comparative Example 1 was used as the comparative reference interlayer film. For Examples 3 and 4 and Comparative Examples 3 and 4, which had the same shape, the interlayer films obtained in Examples 3 and 4 and Comparative Example 4 were used as comparative interlayer films, and the interlayer film obtained in Comparative Example 3 was used as the comparative reference interlayer film. For Examples 5 and 6 and Comparative Examples 5 and 6, which had the same shape, the interlayer films obtained in Examples 5 and 6 and Comparative Example 6 were used as comparative interlayer films, and the interlayer film obtained in Comparative Example 5 was used as the comparative reference interlayer film.

[0288] [Criteria for determining the distance at which voids occur (foaming test)] ○: The reduction rate of the gap distance at both ends is less than 50% △: The reduction rate of the gap distance at both ends is 50% or more but less than 75% ×: The reduction rate of the gap distance is 75% or more at both ends of one end and the other end

[0289] The configuration of the interlayer film and the results are shown in Tables 1 to 3 below.

[0290] [Table 1]

[0291] [Table 2]

[0292] [Table 3] [Explanation of symbols]

[0293] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I...First layer 2, 2A, 2C, 2D, 2G, 2H, 2I...Second layer 3,3A,3C,3D,3G,3H,3I…Third layer 1Ba, 1Ea, 1Fa... Sections with a rectangular cross section in the thickness direction 1Bb, 1Eb, 1Fb... Sections with a wedge-shaped cross section in the thickness direction 11,11A,11B,11C,11D,11E,11F,11G,11H,11I...Intermediate film 11a…one end 11b...other end 11Ba, 11Ea, 11Fa, 11Ia... Sections whose cross-sectional shape in the thickness direction is rectangular 11Bb, 11Eb, 11Fb, 11Ib...portions whose cross-sectional shape in the thickness direction is wedge-shaped 11Ha...First part with constant thickness increase 11Hb...Second part with constant thickness increase 21...Laminated glass 22...First laminated glass member 23...Second laminated glass member

Claims

1. A composition comprising a polyvinyl acetal resin, a light stabilizer, and an antioxidant, a first end and a second end opposite to the first end and having a thickness greater than the first end; The increase in thickness is not constant from the one end to the other end, the light stabilizer is a hindered amine light stabilizer, the hindered amine light stabilizer is a hindered amine light stabilizer in which a carbon atom or an oxygen atom of an alkoxy group is bonded to a nitrogen atom of a piperidine structure, The interlayer film for laminated glass, wherein the light stabilizer has a molecular weight of 2,000 or less.

2. The interlayer film for laminated glass according to claim 1 , wherein the antioxidant is a phenolic antioxidant.

3. 3. The interlayer film for laminated glass according to claim 1, wherein the antioxidant has a molecular weight of 220 or more.

4. 4. The interlayer film for laminated glass according to claim 1, wherein the content of the light stabilizer is 0.01% by weight or more and 0.5% by weight or less, based on 100% by weight of the layer containing the light stabilizer.

5. 5. The interlayer film for laminated glass according to claim 1, wherein a content of the antioxidant is 0.1% by weight or more and 2% by weight or less, based on 100% by weight of the layer containing the antioxidant.

6. The interlayer film for laminated glass according to any one of claims 1 to 5, having at least one of the following configurations (1) to (3): Configuration (1): The intermediate film has a region in which the thickness increases from the one end side to the other end side, and the region in which the thickness increases has a portion in which the amount of increase in thickness varies from the one end side to the other end side. Configuration (2): The intermediate film has, in a region having a wedge-shaped cross section in the thickness direction, a portion in which the wedge angle varies from the one end side to the other end side. Configuration (3): The interlayer film has a portion whose cross section in the thickness direction is rectangular and a portion whose cross section in the thickness direction is wedge-shaped.

7. The interlayer film for laminated glass according to any one of claims 1 to 6, comprising a first layer and a second layer disposed on a first surface side of the first layer.

8. the first layer comprises a polyvinyl acetal resin and a plasticizer; The interlayer film for laminated glass according to claim 7 , wherein the second layer comprises a polyvinyl acetal resin and a plasticizer.

9. 9. The interlayer film for laminated glass according to claim 8, wherein the hydroxyl group content of the polyvinyl acetal resin in the first layer is lower than the hydroxyl group content of the polyvinyl acetal resin in the second layer.

10. 10. The interlayer film for laminated glass according to claim 8 or 9, wherein a content of the plasticizer in the first layer per 100 parts by weight of the polyvinyl acetal resin in the first layer is greater than a content of the plasticizer in the second layer per 100 parts by weight of the polyvinyl acetal resin in the second layer.

11. A device comprising a first layer, a second layer disposed on a first surface side of the first layer, and a third layer disposed on a second surface side of the first layer opposite the first surface, The interlayer film for laminated glass according to any one of claims 1 to 10, wherein the first layer has a portion whose cross section in the thickness direction is wedge-shaped.

12. The first layer comprises a polyvinyl acetal resin and a plasticizer, the second layer contains a polyvinyl acetal resin and a plasticizer, The interlayer film for laminated glass according to claim 11, wherein the third layer comprises a polyvinyl acetal resin and a plasticizer.

13. The interlayer film for laminated glass according to any one of claims 7 to 12, wherein the first layer comprises the light stabilizer and the antioxidant.

14. a first laminated glass member; and a second laminated glass member; and The interlayer film for laminated glass according to any one of claims 1 to 13, The laminated glass, wherein the interlayer film for laminated glass is disposed between the first laminated glass member and the second laminated glass member.

Images