Interlayer film for laminated glass, laminated film, and laminated glass structure

Abstract

The present disclosure provides an interlayer film for laminated glass capable of suitably providing a laminated glass component having good appearance and high safety. The present disclosure also provides a laminated film and a laminated glass structure using such an interlayer film for laminated glass.SOLUTION: An interlayer film for laminated glass includes a polyvinyl acetal resin, and has a film exposure area calculated by a predetermined method of 90 area% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an interlayer film for laminated glass, a laminated film, and a laminated glass structure. [Background technology]

[0002] Conventionally, laminated glass structures have been widely known, in which two glass sheets are integrated by interposing an interlayer film between them. Laminated glass structures are safe because they rarely scatter glass fragments even when broken by external impact, and are therefore widely used in vehicles such as automobiles, aircraft, ships, buildings, etc.

[0003] In recent years, laminated glass structures have been required to have various functions, for example, a functional layer such as a light control film disposed between two glass sheets. Patent Document 1 discloses laminated glass having an interlayer film and a light control element encapsulated in the interlayer film between two glass sheets. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 153998 Summary of the Invention [Problem to be solved by the invention]

[0005] Laminated glass structures are generally manufactured by placing an interlayer between two glass sheets, followed by a preliminary degassing process, followed by an autoclave process in which the glass sheets and the interlayer are pressure-bonded under high-temperature and high-pressure conditions, such as a temperature of approximately 130 to 140°C and a pressure of approximately 1.3 MPa. However, when a functional layer such as a light control film is further placed between the two glass sheets, complex steps (thickness differences) are likely to occur due to the provision of electronic wiring, occlusion printed areas, etc. in the functional layer, and pressure unevenness is also likely to occur during pressure bonding. As a result, air remains or bubbles are generated between the interlayer and the glass sheets or functional layer during pressure bonding, resulting in insufficient transparency in the obtained laminated glass structure and distortions and wrinkles in the functional layer, resulting in an unsatisfactory appearance of the obtained laminated glass structure.

[0006] In laminated glass structures including a functional layer such as a light control film, a frame-shaped intermediate layer (also referred to as a gap filler) is placed around the periphery of the functional layer for the purpose of protecting the edges of the functional layer from the external environment, and this is sandwiched between a pair of intermediate layers, which is then further sandwiched between a pair of glass plates (see, for example, Patent Document 1, etc.). If a laminated glass structure including a functional layer is produced without using a gap filler, in order to improve work efficiency, there are concerns that air will remain or bubbles will form, preventing the laminated glass structure from achieving a good appearance and that the impact resistance will be lower than when a gap filler is used.

[0007] Furthermore, because the functional layer is vulnerable to heat and pressure, bonding a glass plate and an interlayer film having the functional layer under normal high-temperature and high-pressure conditions can cause the functional layer to deteriorate or become inactive. In particular, when the functional layer contains a guest-host liquid crystal (GHLC), the pressure and temperature changes during bonding can cause liquid crystal irregularities in the resulting laminated glass structure, making it unsuitable for practical use. On the other hand, bonding at low temperatures can easily result in residual air or bubbles, making it impossible to obtain a laminated glass structure suitable for practical use.

[0008] The present disclosure has been made in view of the above-described current situation, and aims to provide an interlayer film for laminated glass that can suitably provide a laminated glass structure that has a good appearance and high safety. Another aim of the present disclosure is to provide a laminated film and a laminated glass structure that use such an interlayer film for laminated glass. [Means for solving the problem]

[0009] The present inventors conducted extensive research into interlayer films for laminated glass and discovered that, when the interlayer film contains a polyvinyl acetal resin and has an exposed film area calculated by a predetermined method within a predetermined range, residual air and foaming are suppressed during pressure bonding to glass plates or the like, thereby enabling efficient production of laminated glass structures with good appearance, even without an autoclave process under high temperature and high pressure conditions. Furthermore, when a laminated glass structure is obtained by laminating a functional layer on the interlayer film for laminated glass, the laminated glass structure can effectively exhibit the effects inherent to the functional layer. For example, even when a GHLC film is used as the functional layer and an interlayer film for laminated glass is laminated on the GHLC film, the resulting laminated glass structure can favorably exhibit the functions inherent to the GHLC film without losing them, and liquid crystal unevenness is sufficiently suppressed. Thus, the present inventors have completed the interlayer film for laminated glass and the like of the present disclosure. Specifically, the present disclosure relates to the following interlayer films for laminated glass.

[0010] Disclosure 1 is an interlayer film for laminated glass that contains a polyvinyl acetal resin and has an exposed film area of ​​90% or less by area, calculated by the following method. <Calculation method for exposed membrane area> A sample of a 30 cm x 15 cm interlayer for laminated glass was prepared and maintained at a constant temperature of 23°C and 28% RH for 4 hours. Separately, two 30 cm x 15 cm x 3 mm thick float glass sheets conforming to JIS R3202 (2011) were prepared. The glass and the sample were then laminated so that the tin side of the glass contacted the sample and the sample was positioned between the two sheets of glass. The resulting laminate was pre-pressed using a heated roll at 170°C. The pre-pressed laminate was placed in an autoclave and heated to 90°C at 2°C / min. When the temperature reached 40°C during heating, the pressure was reduced to 0.1 MPa. After reaching 90°C, the temperature was maintained for 20 minutes and then cooled at 2°C / min. When the temperature reached 40°C, the pressure was returned to normal pressure. The resulting optical laminate was left to stand for 16 hours in an environment at a temperature of -18°C ± 0.6°C, and then the optical laminate, fixed at a 45° inclination angle, was struck 72 times per minute with a hammer whose spring screw was adjusted so that the impact force at the top dead center of the stroke was 10.5 ± 0.5 kg. The strikes were performed so that the hammer struck the optical laminate horizontally. The strikes were performed from the bottom of the optical laminate: 13 strikes at 11.5 mm intervals in the horizontal direction (150 mm stroke) and 10 strikes at 9 mm intervals in the vertical direction (90 mm stroke), for a total of 130 strikes. After the strikes, images of the optical laminate were taken, and the area percentage (area %) of the sample where the glass had peeled off and was exposed was analyzed. Disclosure 2 is the interlayer film for laminated glass according to Disclosure 1, wherein the polyvinyl acetal resin has a weight-average molecular weight of 220,000 to 310,000. Disclosure 3 is the interlayer film for laminated glass according to Disclosure 1 or 2, further comprising a plasticizer. Disclosure 4 is the interlayer film for laminated glass according to Disclosure 3, wherein the plasticizer is at least one selected from the group consisting of triethylene glycol-di-2-ethylhexanoate, polyoxyethylene polyoxypropylene glycol, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, and derivatives thereof in which some of the hydrogen atoms of the terminal hydroxyl groups have been substituted with alkyl groups. Disclosure 5 has a creep compliance of 6.0 × 10 per layer at 90 ° C. -5 Pa -1 The interlayer film for laminated glass according to any one of Disclosures 1 to 4 of the present invention is as described above. Disclosure 6 is the interlayer film for laminated glass according to any one of Disclosures 1 to 5, wherein at least one surface of the interlayer film for laminated glass has an uneven shape. Disclosure 7 of the present invention is a laminated film having a structure in which the interlayer film for laminated glass according to any one of Disclosures 1 to 6 of the present invention is laminated with a functional layer. Disclosure 8 is the laminated film of Disclosure 7, which has a structure in which the functional layer is sandwiched between a first interlayer film and a second interlayer film, and at least one of the first interlayer film and the second interlayer film is an interlayer film for laminated glass according to any one of Disclosures 1 to 6. The present disclosure 9 is the laminated film of the present disclosure 7 or 8, wherein the functional layer is at least one selected from the group consisting of a light control film, a display element film, and a solar cell element. The present disclosure 10 is a laminate film according to any one of the present disclosures 7 to 9, wherein the functional layer is a light control film, and the light control film comprises at least one selected from the group consisting of a polymer dispersed liquid crystal (PDLC), a guest-host crystal (GHLC), a suspended particle device (SPD), an electrochemical device, and an electrophoretic film device. Disclosure 11 of the present invention is a laminated glass structure having a structure in which the laminated film of any one of Disclosures 7 to 10 of the present invention is sandwiched between a pair of glass plates. Disclosure 12 is the laminated glass construction of Disclosure 11 made without the use of a gap filler. [Effects of the Invention]

[0011] The present disclosure can provide an interlayer film for laminated glass that can suitably provide a laminated glass structure that has a good appearance and high safety. The present disclosure can also provide a laminated film and a laminated glass structure that use such an interlayer film for laminated glass. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a layer structure of a laminated glass structure. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Interlayer film for laminated glass] The interlayer film for laminated glass of the present disclosure contains a polyvinyl acetal resin and has an exposed film area of ​​90% or less by area, calculated by the above-mentioned method. This exposed film area is preferably 88% or less by area, more preferably 85% or less by area. The lower limit of the exposed film area is 0% by area. Here, for example, clear glass (product name: "Float Plate Glass") manufactured by Sanshiba Glass Materials Co., Ltd. is used as the float glass sheet, and a constant temperature pressurizing device "HP-55-MAH-H14" manufactured by Kyoshin Engineering Co., Ltd. is used as the autoclave. The hammer has a length of 313 mm from the rotation axis to the striking surface, and the striking surface is a protruding surface with a diameter of 30 mm and a length of 20 mm. Image capture and analysis of the captured image (referred to as image analysis) are performed, for example, as follows.

[0014] (Photo taken) Equipment: Rigaku Corporation's 3D micro X-ray CT "StellaScan AX" for veterinary clinics Measurement conditions Tube voltage: 80kV Tube current: CT / Live 250uA FOV: 30mm Capture size: Large Shooting time: 2.5 min Magnification: 1.67x Pixel size: 83.2um / pixel

[0015] After impact, the optical laminate is placed in a bag with a zipper to prevent glass from scattering, and the bag is used for image capture. At this time, a spacer or the like may be used to fix the measurement position. When measuring with the above device, the bag is fixed so that the entire impact surface is included in the X-ray irradiation area, and measurement is performed under the above conditions with Binning set to 1. After measurement is completed, an image is obtained by reconstructing the entire range.

[0016] (Image analysis) The images obtained as described above are analyzed using the image analysis software Avizo 3D Pro 2023.1.1 (Thermo Fisher Scientific) and the open source image analysis software Fiji (ImageJ) according to the following procedure.

[0017] (i) Image cropping Using Avizo 3D Pro 2023.1.1, the "Crop Editor" is applied to the acquired image, and adjustments are made so that the area within at least 10 mm of the edge of the test piece and the area that does not include the unstruck area are extracted. The image size after cropping is, for example, x = 1600, y = 496, z = 900. The XZ cross section is a cross section parallel to the surface of the optical laminate (i.e., a cross section perpendicular to the thickness direction).

[0018] (ii) Extraction of test specimens "Interactive Thresholding" is applied to the image (i) above (i.e., the image cut out in (i) above), and the threshold is adjusted so that the test piece (i.e., the area between the glass piece and the interlayer film for laminated glass) is extracted. Next, "Closing" and "Remove Small Spots" are applied to remove noise from the extracted area. The conditions for each analysis module are, for example, as follows: Interactive Thresholding Intensity Range: 16000-65535 Closing Size:3 Other conditions are set to the initial values. Remove Small Spots Size:1000 Other conditions are set to the initial values.

[0019] (iii) Division of the front and back regions of the test specimen Apply "Invert" to the image (ii) above to invert the extracted area. Then, apply "Separate Objects" to divide the area using the test piece as the boundary. The conditions for each analysis module are, for example, as follows: Invert This is the initial value. Separate Objects Marker Extent:20 Other conditions are set to the initial values.

[0020] (iv) Extraction of image edges in XZ cross sections Create a new label by applying "Add a new label field" in "Segmentation Editor" to the image in (i) above. After creating the label, switch the screen display to the XZ cross section. After that, select the entire region in the first and last images of the slice position, apply "Add" in "SELECTION" and extract only the edge of the image in the XZ cross section.

[0021] (v) Identification of the front and back areas of the test specimen "OR Image" is applied to the image (iii) above, and the extracted area of ​​the image (iv) above is added to the extracted area of ​​the image (iii) above. Then, "Labeling" and "Dilation" are applied to identify the front and back areas of the test piece, respectively. The conditions for each analysis module are, for example, as follows: Labeling This is the initial value. Dilation Size:1 Other conditions are set to the initial values.

[0022] (vi) Extraction of glass fragments Apply "Interactive Thresholding" to the image in (i) above and adjust the threshold so that the glass fragments are extracted. Next, apply "Remove Small Spots" to remove noise from the extracted area. The conditions for each analysis module are, for example, as follows: Interactive Thresholding Intensity Range: 26000-65535 Remove Small Spots Size:10 Other conditions are set to the initial values.

[0023] (vii) Glass particle volume analysis of the specimen surface area "Interactive Thresholding" is applied to the image in (v) above to extract the surface region of the test piece. Next, "AND Image" is applied to extract the region that overlaps with the extracted region in (vi) above. After that, "Label Analysis" is applied to analyze the volume (voxel) of each glass piece extracted region. The conditions for each analysis module are, for example, as follows: Interactive Thresholding Intensity Range: 1-1 Label Analysis This is the initial value.

[0024] (viii) Calculation of the exposed film area ratio of the test piece surface area Using Fiji, apply "Threshold" and "Subtract" to the image obtained in (vii) above to extract the glass area of ​​the test piece and set the brightness value of that area to "1". Next, apply "Reslice" and "Zprojection" to change the image orientation and convert it into a two-dimensional image with integrated brightness values. Next, apply "Threshold" to extract the glass interlayer film area. Then, apply "Set Measurements" and "Measure" to measure the exposed film area. The conditions for each analysis module are, for example, as follows: Threshold (first) Lower threshold level:1 Upper threshold level: 65535 Subtract Value: 254 ·Reslice Start at:Top Z projection Start slice:1 Stop slice:496 Projection type: Sum Slices Threshold (2nd) Lower threshold level: 0 Upper threshold level: 0 Set Measurements Check Area Then, the exposed membrane area ratio was calculated from the obtained exposed membrane area using the following formula: Exposed film area ratio (%) = exposed film area (pixels) / {image size x (pixels) × image size z (pixels)} × 100 The resolution is a value specified by the device.

[0025] (ix) Glass fragment volume analysis of the back region of the specimen "Interactive Thresholding" was applied to the image (v) above to extract the back area of ​​the test piece. Next, "AND Image" was applied to extract the area overlapping with the extracted area (vi) above. Then, "Label Analysis" was applied to analyze the volume (voxel) of each glass piece extracted area. The conditions for each analysis module are, for example, as follows: Interactive Thresholding Intensity Range: 2-2 Label Analysis This is the initial value.

[0026] (x) Extraction of glass fragments from the back area of ​​the test specimen Apply "Interactive Thresholding" to the image in (v) above to extract the surface region of the test piece. Next, apply "AND Image" to extract the region that overlaps with the extracted region in (vi) above. Then, apply "Export Data As..." to output the extracted image. The conditions for each analysis module are, for example, as follows: Interactive Thresholding Intensity Range: 2-2

[0027] (xi) Calculation of the exposed film area ratio on the back of the test piece Using Fiji, apply "Threshold" and "Subtract" to the image obtained in (x) above to extract the glass area of ​​the test piece and set the brightness value of that area to "1". Next, apply "Reslice" and "Zprojection" to change the image orientation and convert it into a two-dimensional image with integrated brightness values. Next, apply "Threshold" to extract the glass interlayer film area. Then, apply "Set Measurements" and "Measure" to measure the exposed film area. The conditions for each analysis module are, for example, as follows: Threshold (first) Lower threshold level:1 Upper threshold level: 65535 Subtract Value: 254 ·Reslice Start at:Top Z projection Start slice:1 Stop slice:496 Projection type: Sum Slices Threshold (2nd) Lower threshold level: 0 Upper threshold level: 0 Set Measurements Check Area Then, the exposed membrane area ratio was calculated from the obtained exposed membrane area using the following formula: Exposed film area ratio (%) = exposed film area (pixels) / {image size x (pixels) × image size z (pixels)} × 100 Calculated based on the following.

[0028] The exposed area of ​​the interlayer film for laminated glass can be easily adjusted within the above range by appropriately adjusting, for example, the amount of hydroxyl groups in the polyvinyl acetal resin, the metal salt content (e.g., the content of the Mg-based adhesion modifier described below), the weight-average molecular weight of the polyvinyl acetal resin, the stereoregularity, and the surface roughness of the interlayer film for laminated glass. Conventional interlayer films for laminated glass may contain magnesium (Mg) salts as adhesion modifiers, such as magnesium acetate, magnesium propionate, magnesium butyrate, magnesium 2-ethylbutyrate, magnesium 2-ethylhexanoate, magnesium octoate, magnesium decanoate, magnesium neodecanoate, and magnesium salts of carboxylic acids having 1 to 16 carbon atoms. However, the interlayer film for laminated glass of the present disclosure preferably does not contain these Mg-based adhesion modifiers. Specifically, the content of the Mg-based adhesion modifier is preferably less than 1 mass%, more preferably less than 0.5 mass%, of the total amount (100 mass%) of the interlayer film for laminated glass of the present disclosure.

[0029] The interlayer film for laminated glass may be a single-layer film having a single-layer structure, or a multilayer film having a multilayer structure. When the interlayer film for laminated glass has multiple layers, the multiple layers may have the same or different structures. For example, the types and contents of the constituent materials (e.g., thermoplastic resins) of the multiple layers may be the same or different. When the interlayer film for laminated glass is a multilayer film, it is preferable that at least one layer contains a polyvinyl acetal resin, and when only this layer is subjected to the above method as a sample, the exposed film area falls within the above range. It is particularly preferable that at least one layer of the multilayer film contains a polyvinyl acetal resin, and when the entire multilayer film is subjected to the above method as a sample, the exposed film area falls within the above range. When the interlayer film for laminated glass has multiple layers, the number of layers is not particularly limited, but may be, for example, two or three layers.

[0030] The creep compliance of each layer of the interlayer film for laminated glass at 90°C is 6.0 x 10 -5 Pa -1 or more. Such an interlayer film has high fluidity under lamination conditions, so that a laminated glass structure can be suitably obtained, for example, without disposing a gap filler around the functional layer. That is, when the interlayer film and the functional layer are disposed between a pair of glass plates and pressure-bonded, peeling at the layer interface and the generation of residual air or bubbles are sufficiently suppressed. Furthermore, even when this pressure-bonding is performed under low-temperature conditions, for example, residual air or bubbles are sufficiently suppressed. Furthermore, even when this pressure-bonding is performed under low-pressure conditions, for example, residual air or bubbles are sufficiently suppressed. Therefore, the resulting laminated glass structure can have superior transparency and a better appearance.

[0031] The creep compliance is 8.0 x 10 -5 Pa -1 More preferably, it is 1.0×10 or more. -4 Pa -1 More preferably, it is 1.3×10 or more. -4 Pa -1The upper limit of the creep compliance is particularly preferably 1.0×10 -3 Pa -1 Preferably, it is 7.0 x 10 or less. -4 Pa -1 Less than 5.0 x 10 is preferable. -4 Pa -1 It is more preferable that the creep compliance is 6.0×10 or less. -5 Pa -1 Over 1.0 x 10 -3 Pa -1 Preferably, it is 6.0 x 10 or less. -5 Pa -1 Over 7.0 x 10 -4 Pa -1 More preferably, it is 6.0×10 or less. -5 Pa -1 Over 5.0 x 10 -4 Pa -1 More preferably, it is 8.0×10 or less. -5 Pa -1 Over 5.0 x 10 -4 Pa -1 More preferably, it is 1.0×10 or less. -4 Pa -1 Over 5.0 x 10 -4 Pa -1 It is particularly preferable that the value is 1.3×10 or less. -4 Pa -1 Over 5.0 x 10 -4 Pa -1 Most preferably, the following:

[0032] The creep compliance at 90° C. per layer is determined as follows. <Method for measuring creep compliance> The measurement device used was the Anton Paar MCR702e MultiDrive dynamic viscoelasticity measurement system (purchased in 2023). Using this measurement device, a circular sample made from one layer of interlayer film, 8 mm in diameter and 0.76 mm thick, was subjected to a shear stress of 400 Pa for 15 minutes at a measurement temperature of 90°C to obtain the creep compliance J(t). The value of the obtained creep compliance J(t) after 10 minutes was taken as the "creep compliance per layer at 90°C" value.

[0033] Here, if the thickness of the sample (interlayer film) to be measured is less than 0.76 mm, several samples may be stacked and press-molded to make the samples uniform in thickness, or if the physical properties of the sample change due to heat pressing, the sample may be measured at its original thickness without being pressed. Furthermore, if the sample thickness is thicker than 0.76 mm, the thickness may be made uniform by press molding or the like, or the sample may be measured at its original thickness. From the viewpoint of measurement accuracy, the measured sample thickness is preferably 0.3 mm or more, and preferably 3 mm or less.

[0034] When setting the sample in the measurement device, the gap is set at room temperature to a pressure of 5 to 10 N to ensure sufficient compression between the sample and the jig, and then the sample is heated to 140°C with the gap fixed. Two minutes after reaching 140°C, the temperature begins to drop to the measurement temperature, and after reaching the measurement temperature, the temperature is held for two minutes before creep compliance measurement begins. Stainless steel parallel plates with a diameter of 8 mm are used as the measurement jig.

[0035] When the interlayer film for laminated glass is a multilayer film, it is preferable that at least one layer thereof satisfies the above creep compliance value. Further, as will be described later, when the interlayer film for laminated glass is laminated on a functional layer to form a laminate or a laminated glass structure, for example, considering the adhesion between the glass plate and the interlayer film for laminated glass, it is preferable that the layer adjacent to the glass plate among the layers constituting the interlayer film for laminated glass satisfies the above creep compliance value. Also, considering the adhesion between the interlayer film for laminated glass and the functional layer, it is preferable that the layer adjacent to the functional layer among the layers constituting the interlayer film for laminated glass satisfies the above creep compliance value, and it is more preferable that all layers satisfy the above creep compliance value.

[0036] The interlayer film for laminated glass preferably has a glass transition temperature (Tg) of -10°C or higher. When Tg is within this range, the penetration resistance and impact resistance are further improved. Tg is more preferably 0°C or higher, still more preferably 10°C or higher, and particularly preferably 15°C or higher. Tg is also preferably 50°C or lower. When Tg is within this range, the adhesion to a glass plate or the like tends to be better. Tg is more preferably 40°C or lower, still more preferably 30°C or lower.

[0037] The Tg of the interlayer film for laminated glass is determined by viscoelasticity measurement. Specifically, it is determined, for example, as follows. <Measurement Method of Tg> The test piece to be measured is stored for 12 hours in an environment of room temperature 23±2°C and humidity 25±5%. Then, using a viscoelasticity measuring device "ARES-G2" manufactured by TA Instruments, viscoelasticity is measured. A parallel plate with a diameter of 8 mm is used as the jig, and the temperature is decreased from 100°C to -20°C at a cooling rate of 3°C / min in shear mode, and measurement is performed under conditions of a frequency of 1 Hz and a strain of 1%. In the obtained measurement results, the peak temperature of the loss tangent is taken as the glass transition temperature Tg (°C).

[0038] The interlayer film for laminated glass contains a polyvinyl acetal resin. That is, the interlayer film for laminated glass has a resin layer containing a polyvinyl acetal resin. Such an interlayer film for laminated glass has good adhesion to various adherends (e.g., functional layers, glass plates, etc.), and the use of this interlayer film can provide a laminated glass structure with excellent impact resistance, etc. Furthermore, by adjusting the weight-average molecular weight of the polyvinyl acetal resin used, the glass transition temperature of the resin, and / or the intermolecular interactions, etc., it is easy to adjust the creep compliance per layer within a predetermined range. When the interlayer film for laminated glass is a multilayer film, it is preferable that at least the layer satisfying the creep compliance value is the resin layer. Note that each of the components contained in the interlayer film for laminated glass may be used alone, or two or more may be used in combination. The polyvinyl acetal resin will be described in detail below.

[0039] Polyvinyl acetal resins are obtained by acetalizing polyvinyl alcohol with an aldehyde. Each of the raw materials for the polyvinyl acetal resins may be used alone or in combination of two or more.

[0040] The aldehyde is not particularly limited, but for example, an aldehyde having 1 to 10 carbon atoms is preferably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and examples thereof include n-butylaldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, and benzaldehyde. Among these, the aldehyde is preferably n-butylaldehyde, n-hexylaldehyde, or n-valeraldehyde, and more preferably n-butylaldehyde. Therefore, the polyvinyl acetal resin is preferably a polyvinyl butyral resin.

[0041] Polyvinyl alcohol can be obtained, for example, by saponifying a polyvinyl ester such as polyvinyl acetate, etc. The degree of saponification of polyvinyl alcohol is generally 70 to 99.9 mol %.

[0042] The average polymerization degree of the polyvinyl alcohol is preferably 1000 to 3000. By using such a polyvinyl alcohol, the polyvinyl acetal resin tends to have a preferred weight-average molecular weight, which will be described later. The average polymerization degree of the polyvinyl alcohol is more preferably 1100 to 2500, further preferably 1200 to 2000, and particularly preferably 1300 to 1700.

[0043] Two or more types of polyvinyl alcohols having different average degrees of polymerization may be used as the polyvinyl alcohol. In this case, it is preferable to produce the polyvinyl acetal resin using a mixture of two or more types of polyvinyl alcohols as a raw material.

[0044] When two or more polyvinyl alcohols are used, it is preferable to use, for example, a first polyvinyl alcohol having an average degree of polymerization of 1500 or more and a second polyvinyl alcohol having an average degree of polymerization of 1200 or less. The average degree of polymerization of the first polyvinyl alcohol is preferably 1500 to 3500, more preferably 1600 to 2500, and even more preferably 1600 to 2000. The average degree of polymerization of the second polyvinyl alcohol is preferably 200 to 1200, more preferably 300 to 900, and even more preferably 400 to 850.

[0045] When the first polyvinyl alcohol and the second polyvinyl alcohol are used in combination, their blending ratio is not particularly limited. For example, the blending amount of the second polyvinyl alcohol is preferably 1 to 50 mass%, more preferably 3 to 40 mass%, even more preferably 5 to 35 mass%, and particularly preferably 10 to 30 mass%, relative to 100 mass% of the total amount of the first polyvinyl alcohol and the second polyvinyl alcohol.

[0046] The average degree of polymerization of polyvinyl alcohol is determined by a method conforming to JIS K6726 (1994) "Testing Method for Polyvinyl Alcohol." When two or more types of polyvinyl alcohol are used as raw materials, the average degree of polymerization of polyvinyl alcohol can be estimated by calculation from the average degree of polymerization of each polyvinyl alcohol.

[0047] The polyvinyl acetal resin preferably has a weight-average molecular weight of 100,000 to 300,000. This further improves the adhesion of the interlayer film to various substrates and the penetration resistance of the laminated glass structure. Furthermore, using a polyvinyl acetal resin having a weight-average molecular weight within the above range makes it easier to adjust the creep compliance per interlayer film layer within the above range. The lower limit of the weight-average molecular weight of the polyvinyl acetal resin is more preferably 180,000 or more, even more preferably 210,000 or more, and particularly preferably 220,000 or more. The upper limit of the weight-average molecular weight of the polyvinyl acetal resin is more preferably 280,000 or less, even more preferably 260,000 or less, and particularly preferably 250,000 or less. The weight average molecular weight of the polyvinyl acetal resin is more preferably in the range of 180,000 to 280,000, further preferably 210,000 to 260,000, and particularly preferably 220,000 to 250,000.

[0048] The weight average molecular weight of the polyvinyl acetal resin can be determined, for example, by the following measurement method using gel permeation chromatography. <Method for measuring molecular weight> Polyvinyl acetal resin is dissolved in N-methyl-2-pyrrolidone solution containing lithium bromide to a concentration of 10 mM to obtain a solution with a polyvinyl acetal resin concentration of 0.05% by mass. The resulting solution is filtered using a syringe filter (Millex-LH 0.45 μm, manufactured by Merck) and then the molecular weight is measured using gel permeation chromatography (e2690, manufactured by Waters). The weight-average molecular weight (Mw) is calculated using a molecular weight calibration curve prepared using monodisperse polystyrene standard samples. The column used is Shodex GPC KF-806L (Showa Denko KK), and the eluent used is an N-methyl-2-pyrrolidone solution containing lithium bromide added to a concentration of 10 mM.

[0049] The hydroxyl group content of the polyvinyl acetal resin is preferably 15 mol% or more. This tends to improve the adhesion of the interlayer film to various substrates, and the resulting laminated glass structure has excellent penetration resistance and other properties. The hydroxyl group content of the polyvinyl acetal resin is preferably 38 mol% or less. This improves the flexibility of the interlayer film and prevents the resulting laminated glass structure from becoming too hard. Furthermore, when the hydroxyl group content of the polyvinyl acetal resin is within the above range, the generation of bubbles during use in a high-temperature environment is sufficiently suppressed, further improving the high-temperature heat resistance of the interlayer film. The lower limit of the hydroxyl group content is more preferably 20 mol% or more, and even more preferably 25 mol% or more. The upper limit of the hydroxyl group content is more preferably 35% or less, and even more preferably 33 mol% or less.

[0050] When a polyvinyl butyral resin is used as the polyvinyl acetal resin, from the same viewpoint, the lower limit of the hydroxyl group content is preferably 15 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more, and the upper limit of the hydroxyl group content of the polyvinyl butyral resin is preferably 38 mol% or less, more preferably 35% or less, and even more preferably 33 mol% or less.

[0051] The amount of hydroxyl groups in a polyvinyl acetal resin is the molar fraction calculated by dividing the amount of ethylene groups to which hydroxyl groups are bonded by the total amount of ethylene groups in the main chain, expressed as a percentage. The amount of ethylene groups to which hydroxyl groups are bonded can be measured, for example, in accordance with JIS K6728 (1977) "Testing Methods for Polyvinyl Butyral."

[0052] The degree of acetalization of the polyvinyl acetal resin is preferably 47 mol% or more, more preferably 55 mol% or more, and even more preferably 60 mol% or more. The degree of acetalization of the polyvinyl acetal resin is also preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less. Note that when the acetal group is a butyral group and the polyvinyl acetal resin is a polyvinyl butyral resin, the degree of acetalization refers to the degree of butyralization.

[0053] The degree of acetalization of a polyvinyl acetal resin is a molar fraction calculated by subtracting the number of ethylene groups having hydroxyl groups and the number of ethylene groups having acetyl groups from the total number of ethylene groups in the main chain, and dividing the result by the total number of ethylene groups in the main chain, and the percentage of the molar fraction is expressed as a percentage. The degree of acetalization can be calculated, for example, from the results of measurements performed according to JIS K6728 (1977) "Testing Methods for Polyvinyl Butyral."

[0054] The degree of acetylation of the polyvinyl acetal resin is preferably 30 mol% or less. This improves the moisture resistance of the interlayer film. The upper limit of the degree of acetylation is more preferably 20 mol% or less, even more preferably 10 mol% or less, and particularly preferably 2 mol% or less. The lower limit of the degree of acetylation is not particularly limited, but is preferably 0.01 mol% or more, more preferably 0.1 mol% or more.

[0055] The degree of acetylation of a polyvinyl acetal resin is the molar fraction calculated by dividing the amount of ethylene groups bonded to acetyl groups by the total amount of ethylene groups in the main chain, and is expressed as a percentage. The amount of ethylene groups bonded to acetyl groups can be measured, for example, in accordance with JIS K6728 (1977) "Testing Methods for Polyvinyl Butyral."

[0056] The polyvinyl acetal resin is preferably an unmodified polyvinyl acetal resin, but may also be a modified polyvinyl acetal resin. A modified polyvinyl acetal resin is one having a structure (modifying group) other than an acetal group, a hydroxyl group, and an acetyl group, and preferably has a modifying group on its side chain. Examples of the modifying group include those having a polyalkylene oxide structure on the side chain, and those having an alkyl group (e.g., having about 2 to 30 carbon atoms) other than an acetal group or an acetyl group on the side chain. The modification amount is not particularly limited, but is, for example, about 0.1 mol % to 10 mol %. The modification amount refers to the ratio of functional groups to all vinyl monomer units constituting the polyvinyl acetal resin.

[0057] The interlayer film for laminated glass may further contain a thermoplastic resin other than polyvinyl acetal resin. Examples of thermoplastic resins other than polyvinyl acetal resin include (meth)acrylic resins, polyvinyl alcohol resins, polyurethane resins (PU), ethylene-vinyl acetate copolymer resins (EVA), saponified ethylene-vinyl acetate copolymers (EVOH), ethylene-methacrylic acid copolymer resins, ionomer resins, isobutylene resins, styrene-isoprene copolymer resins, and styrene-butadiene copolymer resins. However, it is preferred that the main component of the resin constituting the interlayer film for laminated glass is polyvinyl acetal resin. Specifically, out of the total 100% by mass of resin components constituting the resin layers constituting the interlayer film for laminated glass (or each resin layer if the interlayer film has multiple resin layers), polyvinyl acetal resin preferably accounts for 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and most preferably 100% by mass. That is, it is most preferred that the resin constituting the interlayer film for laminated glass is polyvinyl acetal resin alone.

[0058] The polyvinyl acetal resin is preferably produced by a production method including, for example, a mixing step of mixing polyvinyl alcohol with an aldehyde and a aging step of aging the mixture obtained in the mixing step. The acetalization of polyvinyl alcohol proceeds through the mixing step and the aging step, thereby producing the polyvinyl acetal resin. Note that, for example, when producing a thermoplastic resin such as a polyvinyl acetal resin, the intermolecular interaction can be adjusted by changing the reaction conditions and aging conditions.

[0059] In the mixing step, polyvinyl alcohol and aldehyde may be mixed according to a conventional method. In addition to polyvinyl alcohol and aldehyde, a catalyst such as an acid catalyst may be added to promote the acetalization reaction. For example, the aldehyde may be added to a mixture of polyvinyl alcohol and an acid catalyst at a low temperature of about 0 to 40°C. When two or more polyvinyl alcohols are used in combination (for example, when two or more polyvinyl alcohols having different molecular weights are used), the two or more polyvinyl alcohols may be mixed with the aldehyde.

[0060] In the aging step, for example, a catalyst such as an acid catalyst is added to the mixture (reaction mixture) obtained in the mixing step, followed by heating to an aging temperature and maintaining the mixture at the aging temperature for a certain period of time. After maintaining the reaction mixture at the aging temperature for a certain period of time, the reaction mixture may be appropriately cooled or neutralized, and then washed with water, dried, or the like, as necessary.

[0061] Examples of acid catalysts that can be added in the mixing step and the aging step include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, boric acid, sulfuric acid, etc. In the aging step, the concentration of the acid catalyst is preferably adjusted to, for example, about 0.5% by mass to about 5% by mass, and more preferably about 1% by mass to about 2.5% by mass.

[0062] The aging temperature in the aging step may be relatively low, for example, preferably 40°C to 60°C, more preferably 35°C to 60°C, and even more preferably 40°C to 57°C. The time for which the aging temperature is maintained (aging time) may be longer than a certain period, for example, preferably 75 minutes to 180 minutes, more preferably 90 minutes to 150 minutes, and even more preferably 100 minutes to 140 minutes. It is presumed that when the aging temperature and aging time are within the above ranges, hydroxyl groups in the polyvinyl acetal resin are more likely to be uniformly distributed throughout the molecule, which is thought to result in fewer low-molecular-weight components and a narrower molecular weight distribution.

[0063] (plasticizer) The interlayer film for laminated glass preferably further contains a plasticizer. That is, the resin layer preferably further contains a plasticizer. By including a plasticizer in addition to the polyvinyl acetal resin in the interlayer film for laminated glass, the interlayer film becomes more flexible, thereby improving the adhesion of the interlayer film to various substrates and the penetration resistance of the laminated glass structure obtained using the interlayer film. Furthermore, adjusting the type and content of the plasticizer makes it easier to adjust the creep compliance per interlayer film layer within a predetermined range.

[0064] Preferred examples of the plasticizer include organic ester plasticizers, organic phosphate ester plasticizers such as organic phosphate ester plasticizers and organic phosphite ester plasticizers, organic ether plasticizers such as polyalkylene glycol plasticizers, and alcohol plasticizers. Among these, the plasticizer is preferably an organic ester plasticizer and / or an organic ether plasticizer.

[0065] Preferred examples of the organic ester plasticizer include monobasic organic acid esters and polybasic organic acid esters.

[0066] Examples of monobasic organic acid esters include esters of glycols and monobasic organic acids. The glycol is preferably a polyalkylene glycol or a monoalkylene glycol. The number of carbon atoms in each alkylene unit constituting the polyalkylene glycol or monoalkylene glycol is preferably 2 to 4, more preferably 2 or 3. In addition, the number of repeating alkylene units in the polyalkylene glycol is preferably 2 to 10, more preferably 2 to 4. Specific examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and butylene glycol. In addition, examples of monobasic organic acids include organic acids having 3 to 10 carbon atoms, such as butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octylic acid, 2-ethylhexyl acid, n-nonylic acid, and decylic acid.

[0067] Specific examples of the monobasic organic acid ester include 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, tetraethylene glycol di-2-ethylhexanoate, diethylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol Examples of the diethylene glycol di-2-ethyl butyrate include glycerol di-2-ethylpentanoate, tetraethylene glycol di-2-ethyl butyrate, diethylene glycol dicaprylate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, triethylene glycol di-2-ethyl butyrate, ethylene glycol di-2-ethyl butyrate, 1,2-propylene glycol di-2-ethyl butyrate, 1,3-propylene glycol di-2-ethyl butyrate, 1,4-butylene glycol di-2-ethyl butyrate, and 1,2-butylene glycol di-2-ethyl butyrate.

[0068] Examples of polybasic organic acid esters include ester compounds of dibasic organic acids having 4 to 12 carbon atoms and alcohols having 4 to 10 carbon atoms. Examples of dibasic organic acids having 4 to 12 carbon atoms include adipic acid, sebacic acid, and azelaic acid. The alcohols having 4 to 10 carbon atoms may be linear, have a branched structure, or have a cyclic structure.

[0069] Specific examples of polybasic organic acid esters include dibutyl sebacate, dioctyl azelaate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl carbitol adipate, and mixed adipates. The polybasic organic acid ester may also be an oil-modified alkyd sebacate. Examples of mixed adipates include adipates prepared from two or more alcohols selected from the group consisting of alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms.

[0070] The organic ester plasticizer is not limited to a complete ester of each of the above esters, but may also be a partial ester. For example, the organic ester plasticizer may be a partial ester of a glycol and a monobasic organic acid, or a partial ester of a dibasic organic acid and an alcohol. Specific examples include triethylene glycol-mono-2-ethylhexanoate.

[0071] The organic ester plasticizer may also be a partial ester of a trivalent or higher alcohol such as glycerin with a monobasic organic acid. The number of carbon atoms in the monobasic organic acid is preferably 3 to 24, and more preferably 6 to 18. Specific examples include a mono- or diester of glycerin and stearic acid, and a mono- or diester of glycerin and 2-ethylhexyl acid.

[0072] Among the above-mentioned organic ester plasticizers, triethylene glycol-di-2-ethylhexanoate (3GO) is particularly preferably used.

[0073] Preferred examples of the organic phosphorus plasticizer include organic phosphate ester plasticizers, organic phosphite ester plasticizers, etc. Specific examples of the organic phosphorus plasticizer include phosphate esters such as tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

[0074] A preferred example of an organic ether-based plasticizer is a polyalkylene glycol-based plasticizer. Examples of polyalkylene glycol-based plasticizers include polyoxyalkylene compounds having a polyoxyalkylene structure, specifically polyhydric alcohol compounds such as glycol; ester compounds of glycol with a monobasic organic acid or a polybasic organic acid; and ether compounds of a monohydric or polyhydric alcohol with a polyoxyalkylene. Examples of glycols include polyoxyalkylene glycols and their derivatives, and examples of polyoxyalkylenes include polyoxyethylene, polyoxypropylene, polyoxybutylene, and random or block copolymers thereof. The polyoxyalkylene compound may be a polyhydric alcohol compound, an ester compound, an ether compound, or other compounds, as described above.

[0075] Examples of polyoxyalkylene compounds include polyoxyalkylene and its derivatives. More specifically, examples include polyoxyalkylene glycols composed of polyoxyalkylene, and ether compounds of polyoxyalkylene and polyhydric alcohols. All of these compounds may have hydroxyl groups at their terminals, or may be derivatives in which some or all of the hydrogen atoms at the terminal hydroxyl groups have been substituted with alkyl groups or acyl groups. The number of carbon atoms in the alkyl and acyl groups is not particularly limited, but may be about 1 to 8, preferably 1 to 4.

[0076] Examples of polyoxyalkylene glycols include polyoxyethylene polyoxypropylene glycols such as polyethylene glycol (polyoxyethylene glycol), polypropylene glycol (polyoxypropylene glycol), poly(ethylene oxide / propylene oxide) block copolymers and poly(ethylene oxide / propylene oxide) random copolymers, and polyoxybutylene glycols such as polytetramethylene glycol.

[0077] Examples of ether compounds of polyoxyalkylenes and polyhydric alcohols include ether compounds of polyoxyalkylenes with polyhydric alcohols such as glycerol, diglycerol, trimethylolpropane, erythritol, pentaerythritol, and bisphenol A, specifically polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether, polyoxyalkylene pentaerythritol ether, etc. Examples of derivatives in which some or all of the hydrogen atoms of terminal hydroxyl groups have been substituted with alkyl groups or acyl groups include the above-mentioned polyoxyalkylene glycols and derivatives in which some or all of the hydrogen atoms of terminal hydroxyl groups of ether compounds have been substituted with alkyl groups or acyl groups. Specific examples include polyoxyethylene glycol monomethyl ether, polyoxyethylene glycol dimethyl ether, polyoxypropylene glycol monomethyl ether, polyoxypropylene glycol dimethyl ether, polyoxyethylene polyoxypropylene glycol monomethyl ether, polyoxyethylene polyoxypropylene glycol dimethyl ether, polyoxyethylene glycol monobutyl ether, polyoxypropylene glycol monobutyl ether, and polyoxyethylene polyoxypropylene monobutyl ether.

[0078] Among the above-mentioned polyoxyalkylene compounds, compounds having a polyoxyethylene structure, a polyoxypropylene structure, or a polyoxyethylene polyoxypropylene structure are preferred, and among these, compounds having a polyoxypropylene structure or a polyoxyethylene polyoxypropylene structure are more preferred.Specifically, the polyoxyalkylene compound is preferably polyoxyethylene polyoxypropylene glycol, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, or a derivative thereof in which some of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups.

[0079] Preferred examples of the alcohol-based plasticizer include various polyhydric alcohols such as butanediol, hexanediol, trimethylolpropane, pentaerythritol, etc. Among these, trimethylolpropane is preferred.

[0080] Among the above-mentioned compounds, the plasticizer is preferably at least one selected from the group consisting of triethylene glycol-di-2-ethylhexanoate (3GO), polyoxyethylene polyoxypropylene glycol, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, and derivatives thereof in which some of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups, and 3GO is more preferred.

[0081] When the resin layer further contains a plasticizer, the content of the plasticizer (total amount when two or more types are contained) is preferably, for example, 10 parts by mass or more per 100 parts by mass of the thermoplastic resin contained in the resin layer (one layer). This makes the interlayer film moderately flexible, further improving the adhesion of the interlayer film to various substrates and the penetration resistance of the laminated glass structure. The content of the plasticizer per 100 parts by mass of the thermoplastic resin is more preferably 15 parts by mass or more, even more preferably 30 parts by mass or more, and particularly preferably 35 parts by mass or more. The content of the plasticizer is also preferably 100 parts by mass or less per 100 parts by mass of the thermoplastic resin. This sufficiently prevents the plasticizer from separating from the interlayer film. The content of the plasticizer per 100 parts by mass of the thermoplastic resin is more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, particularly preferably 50 parts by mass or less, and most preferably 45 parts by mass or less.

[0082] (Other additives) The interlayer film for laminated glass may also contain, as appropriate, known additives that can be used in combination with polyvinyl acetal resins, etc. That is, for example, the resin layer may contain known additives. Examples of additives other than plasticizers include ultraviolet absorbers, heat shielding agents, colorants, infrared absorbers, antioxidants, light stabilizers, adhesion modifiers, fluorescent brightening agents, and crystal nucleating agents. Each of the additives may be used alone, or two or more may be used in combination.

[0083] (ultraviolet absorber) When the interlayer film for laminated glass contains an ultraviolet absorber, deterioration of the functional layer due to ultraviolet rays is sufficiently suppressed. For example, it is preferable that the resin layer in at least one of the interlayer films for laminated glass further contains an ultraviolet absorber.

[0084] The ultraviolet absorber is not particularly limited, and examples thereof include compounds having a malonic acid ester structure, compounds having an oxalic acid anilide structure, compounds having a benzotriazole structure, compounds having a benzophenone structure, compounds having a triazine structure, compounds having a benzoate structure, compounds having a hindered amine structure, and compounds having an indole structure. Among these, the ultraviolet absorber is preferably a compound having a benzotriazole structure from the viewpoint of excellent compatibility with thermoplastic resins and weather resistance. Examples of commercially available compounds having a benzotriazole structure include Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 640, and Tinuvin 928 (manufactured by BAF), and Eversorb 88 and Eversorb 109 (manufactured by Everlight Chemical).

[0085] When the resin layer contains an ultraviolet absorber, the content of the ultraviolet absorbers (the total amount when two or more types are contained) is, for example, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on 100% by mass of the total amount of materials constituting the resin layer (one layer). The content of the ultraviolet absorbers is also preferably 5% by mass or less, more preferably 3% by mass or less, based on 100% by mass of the total amount of materials constituting the resin layer (one layer).

[0086] (heat shielding agent) When the interlayer film for laminated glass contains a heat-shielding agent, deterioration of the functional layer due to heat is sufficiently suppressed. For example, it is preferable that the resin layer of the polyvinyl acetal resin further contains a heat-shielding agent. Furthermore, the polyvinyl acetal resin may have, separately from or in addition to the resin layer, a layer made of a heat-shielding agent (for example, a layer made of heat-shielding particles described below) or a layer containing a heat-shielding agent.

[0087] The heat-shielding agent is a material capable of absorbing infrared rays (also called heat rays) of 780 nm or more. Specifically, the heat-shielding agent is preferably heat-shielding particles. The heat-shielding particles are made of an inorganic material, and specific examples thereof include metal oxide particles and particles other than metal oxide particles, such as lanthanum hexaboride (LaB6) particles. Examples of metal oxide particles include tin oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, and antimony-doped tin oxide particles (ATO particles); zinc oxide particles such as gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminum-doped zinc oxide particles (AZO particles), tin-doped zinc oxide particles, and silicon-doped zinc oxide particles; titanium oxide particles such as niobium-doped titanium oxide particles; indium oxide particles such as tin-doped indium oxide particles (ITO particles); sodium-doped tungsten oxide particles and cesium-doped tungsten oxide particles (CWO particles); and tungsten oxide particles such as thallium-doped tungsten oxide particles and rubidium-doped tungsten oxide particles. Heat-shielding particles other than these may also be used. Among these, from the viewpoint of high heat ray shielding function, the heat shielding agent is preferably metal oxide particles, more preferably at least one selected from the group consisting of ATO particles, GZO particles, ITO particles and CWO particles, and more preferably ITO particles and / or CWO particles.

[0088] The lower limit of the average particle size of the heat-shielding particles is preferably 10 nm or more, and more preferably 20 nm or more. When the average particle size is within this range, the heat-shielding particles have an even greater ability to shield against heat rays. Furthermore, the upper limit of the average particle size of the heat-shielding particles is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. When the average particle size is within this range, the heat-shielding particles are less able to shield against visible light. Note that the "average particle size" referred to here refers to the volume-average particle size. The average particle size can be measured using a particle size distribution analyzer ("UPA-EX150" manufactured by Nikkiso Co., Ltd.) or the like.

[0089] The heat-shielding agent may also be an organic material or an organic-inorganic composite material (also referred to as a shielding compound) capable of absorbing infrared rays, which are also near-infrared absorbers. Near-infrared absorbers have an absorption maximum in the near-infrared region, and this absorption maximum is the largest among the absorption maximums present in the wavelength region of 380 nm to 2500 nm. Specifically, near-infrared absorbers have a maximum absorption in the wavelength region of 720 nm or more, preferably in the wavelength region of 750 nm or more and 2000 nm or less.

[0090] The heat-shielding compound is preferably at least one selected from the group consisting of a phthalocyanine compound, a naphthalocyanine compound, and an anthracyanine compound. The phthalocyanine compound is phthalocyanine or a phthalocyanine derivative having a phthalocyanine skeleton, and preferably contains a metal atom. The naphthalocyanine compound is naphthalocyanine or a naphthalocyanine derivative having a naphthalocyanine skeleton, and preferably contains a metal atom. The anthracyanine compound is an anthracyanine or an anthracyanine derivative having an anthracyanine skeleton, and preferably contains a metal atom. In the phthalocyanine compound, the naphthalocyanine compound, and the anthracyanine compound, the metal atom is the central metal of the naphthalocyanine skeleton, the naphthalocyanine skeleton, and the anthracyanine skeleton, respectively.

[0091] Among the above, the heat-shielding compound is preferably at least one selected from the group consisting of phthalocyanine compounds and naphthalocyanine compounds, and more preferably a phthalocyanine compound. Furthermore, the metal atom is preferably a vanadium atom. Therefore, the heat-shielding compound is particularly preferably a phthalocyanine compound containing a vanadium atom. The vanadium atom generally exists in a state where an oxygen atom is bonded to it (V=O). Furthermore, it is also preferable to use tungsten oxide particles and a phthalocyanine compound in combination as the heat-shielding agent, and it is more preferable to use CWO particles and a phthalocyanine compound in combination.

[0092] When the resin layer contains a heat-shielding agent, the content of the heat-shielding agent (total amount when two or more types are contained) is, for example, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.15% by mass or more, based on 100% by mass of the total amount of materials constituting the resin layer (one layer). The content of the heat-shielding agent is also preferably 1.5% by mass or less, more preferably 1.2% by mass or less, and even more preferably 0.9% by mass or less, based on 100% by mass of the total amount of materials constituting the resin layer (one layer).

[0093] (coloring agent) When the interlayer film for laminated glass contains a colorant, the laminated glass structure obtained using the interlayer film is well colored to a desired color tone, improving the design. For example, it is preferable that the resin layer of the interlayer film for laminated glass further contains a colorant. Examples of the colorant include pigments and dyes, and both pigments and dyes may be used in combination. Note that there are also colorants that are classified as both pigments and dyes.

[0094] Examples of pigments include perylene compounds, threne compounds, quinacridone compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, perinone compounds, phthalocyanine compounds, indanthrene compounds, indigo compounds, isoindolinone compounds, nickel complex compounds, methine compounds, azomethine compounds, dioxazines, azo compounds, and carbon black.

[0095] Examples of dyes include perylene compounds, threne compounds, quinacridone compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, perinone compounds, phthalocyanine compounds, indanthrene compounds, indigo compounds, isoindolinone compounds, nickel complex compounds, methine compounds, azomethine compounds, dioxazines, and azo compounds.

[0096] When the resin layer contains a colorant, the content of the colorant (the total amount when two or more types are contained) is, for example, preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, and even more preferably 0.001% by mass or more, based on 100% by mass of the total amount of materials constituting the resin layer (one layer).The content of the dye is also preferably 0.15% by mass or less, more preferably 0.12% by mass or less, based on 100% by mass of the total amount of materials constituting the resin layer (one layer).

[0097] When the interlayer film for laminated glass contains a pigment as a colorant, the pigment content (total amount when two or more types are contained) is, for example, preferably 0.0001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.02% by mass or more, based on 100% by mass of the total amount of materials constituting the resin layer (one layer). The pigment content is also preferably 0.15% by mass or less, more preferably 0.12% by mass or less, based on 100% by mass of the total amount of materials constituting the resin layer. The interlayer film may contain only one type of pigment, two or more types, three or more types, or ten or fewer types, or five or fewer types.

[0098] When the interlayer film for laminated glass contains a dye as a colorant, the content of the dye (total amount when two or more types are contained) is, for example, preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, and even more preferably 0.001% by mass or more, based on 100% by mass of the total amount of materials constituting the resin layer (one layer). The content of the dye is also preferably less than 0.015% by mass, more preferably 0.01% by mass or less, based on 100% by mass of the total amount of materials constituting one resin layer. The interlayer film may contain only one type of dye, but may also contain two or more types, three or more types, or ten or fewer types, or five or fewer types.

[0099] (Thickness) The thickness of the interlayer film for laminated glass is not particularly limited, but the layer thickness of the interlayer film (meaning the total thickness in the case of a multilayer film) is preferably 100 μm or more, more preferably 200 μm or more, and even more preferably 300 μm or more. When the interlayer film for laminated glass has a certain thickness or more, residual air and bubbles are more sufficiently suppressed when the interlayer film for laminated glass is pressure-bonded to the glass sheets.

[0100] The thickness (total thickness) of the interlayer film for laminated glass is preferably 2000 μm or less, more preferably 1300 μm or less, even more preferably 1000 μm or less, and particularly preferably 800 μm or less. By keeping the thickness of the interlayer film for laminated glass at a certain level or less, for example, the laminated glass structure obtained using the interlayer film can be prevented from becoming thicker than necessary.

[0101] It is preferable that the thickness of the layer that satisfies the above creep compliance value accounts for a certain percentage or more of the total thickness of the interlayer film for laminated glass. This more sufficiently suppresses residual air and bubbles when the interlayer film for laminated glass is pressed against the glass plate. For example, when the interlayer film for laminated glass is a multilayer film, the thickness of the layer that satisfies the above creep compliance value is preferably 10 to 100%, more preferably 30 to 100%, even more preferably 50 to 100%, particularly preferably 75 to 100%, and most preferably 100%, of the total thickness (total thickness) of the interlayer film for laminated glass taken as 100%.

[0102] As will be described later, when a laminated glass structure is constructed using the above interlayer film for laminated glass, the thickness of the layer that satisfies the above creep compliance value (the total thickness when two or more such layers are included) is preferably 10 to 50%, more preferably 20 to 40%, of the total thickness of the laminated glass structure (100%).

[0103] (Uneven shape) At least one surface of the interlayer film for laminated glass preferably has an uneven shape. More specifically, at least one surface of the interlayer film preferably has a plurality of recesses and a plurality of protrusions, and more preferably both surfaces of the interlayer film have a plurality of recesses and a plurality of protrusions. Furthermore, when the interlayer film for laminated glass is a multilayer film, it is preferable that one or both surfaces of the outermost layer of the interlayer film have an uneven shape.

[0104] The recesses preferably have a groove shape with a continuous bottom. A groove shape with a continuous bottom is also referred to as a "ruled line" shape. Therefore, the surface of the interlayer film for laminated glass preferably has ruled line-shaped recesses, and it is more preferable that both surfaces of the interlayer film have ruled line-shaped recesses. For example, when attempting to pre-bond a glass plate and an interlayer film using a rubber bag to obtain a laminated glass structure, the edges may be temporarily bonded first, making it difficult for air to escape near the center. However, if the surface of the interlayer film has ruled line-shaped recesses, air near the center can also be easily released, improving adhesion during pre-bonding.

[0105] At least one surface of the interlayer film for laminated glass preferably has a plurality of ruled recesses. In this case, it is preferable that the ruled recesses are arranged in parallel, and it is even more preferable that adjacent ruled recesses are arranged in a regular, parallel arrangement. The ease with which air escapes (also referred to as degassing ability) when a laminate film in which an interlayer film is laminated between a pair of glass plates is pressure-bonded is closely related to the interconnectedness and smoothness of the bottoms of the recesses on the interlayer film surface. By forming the irregular shape of at least one surface of the interlayer film in a shape in which adjacent ruled recesses are arranged in a regular, parallel arrangement, the interconnectedness of the bottoms is improved, and degassing ability is further improved.

[0106] The spacing Sm between adjacent ruled recesses is preferably 100 μm or more and preferably 500 μm or less. When the spacing Sm between the ruled recesses is within this range, even better degassing properties are exhibited. The lower limit of the spacing Sm between the ruled recesses is more preferably 160 μm or more, and the upper limit is more preferably 350 μm or less, and even more preferably 250 μm or less. The spacing Sm between the ruled recesses is determined by observing the first and second surfaces of the interlayer film (observation area 20 mm × 20 mm) using an optical microscope (SONIC Corporation, "BS-D8000III"), measuring the spacing between adjacent recesses, and then calculating the average of the shortest distances between the bottoms of adjacent recesses.

[0107] In the regularly arranged parallel ruled recesses, adjacent ruled recesses are preferably parallel and equally spaced, but the intervals between all adjacent ruled recesses do not have to be equal. The ruled recesses do not need to have a continuous groove shape across the entire bottom, and may have a dividing wall in part of the bottom. Furthermore, as long as adjacent recesses are parallel and regularly arranged, the groove shape at the bottom does not have to be linear. For example, the groove shape at the bottom may be wavy or zigzag.

[0108] In an interlayer film having an uneven surface on at least one side, the surface roughness (RzJIS94) of the uneven surface is preferably 10 to 80 μm. When the surface roughness is within this range, the interlayer film can exhibit excellent degassing properties. The surface roughness is more preferably 20 to 65 μm, and even more preferably 20 to 50 μm.

[0109] Surface roughness (RzJIS94) can be measured in accordance with JIS B0601 (1994). When the concave portions of the surface texture are in the form of scribed lines, measurements are taken perpendicular to the direction in which the concave portions of the scribed lines continue. For example, a measuring instrument such as the "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. is used. The cutoff value during measurement is 2.5 mm, the reference length is 2.5 mm, the measurement length is 12.5 mm, the preliminary length is 2.5 mm, the palpation needle feed rate is 0.5 mm / sec, and the palpation needle shape has a tip radius of 2 μm and a tip angle of 60°. The measurement is performed in an environment of 23°C and 30% RH. The interlayer film to be measured is allowed to stand in the measurement environment for at least 3 hours before measurement.

[0110] Furthermore, in an interlayer film having an uneven surface on at least one side, the surface roughness (Rc) of the uneven surface is preferably 10 to 40 μm. When the surface roughness is within this range, the interlayer film can exhibit excellent degassing properties. The surface roughness (Rc) is more preferably 15 to 35 μm, and even more preferably 19 to 30 μm. The surface roughness (Rc) can be measured in accordance with JIS B0601 (2013).

[0111] The interlayer film for laminated glass can be produced by, for example, extrusion molding or press molding, but extrusion molding is preferred. Examples of methods for forming a textured surface on the interlayer film include the embossing roll method, the calendar roll method, the profile extrusion method, and the melt fracture method. Of these, the embossing roll method is preferred.

[0112] [Laminated film] The laminated film of the present disclosure has a structure in which the interlayer film for laminated glass of the present disclosure described above and a functional layer are laminated. For example, the laminated film of the present disclosure has a structure in which a functional layer is sandwiched between a first interlayer film and a second interlayer film, and at least one of the first interlayer film and the second interlayer film is the interlayer film for laminated glass of the present disclosure described above. The first interlayer film and the second interlayer film may have the same configuration as each other, or may be different. Furthermore, it is preferable that both the first interlayer film and the second interlayer film are the interlayer film for laminated glass of the present disclosure described above.

[0113] The functional layer is preferably located between the first interlayer film and the second interlayer film. The functional layer is not particularly limited as long as it is a layer having a predetermined function, but is preferably a functional film. The functional film is preferably, for example, a light control film, a display element film, a hologram film, or an optical film, and examples of optical films include a polarizing film, a retardation film, and an anti-reflection film. The functional layer may also be a solar cell element, as described below. An embodiment in which the functional layer is at least one selected from the group consisting of a light control film, a display element film, and a solar cell element is one of the preferred embodiments of the laminate film of the present disclosure.

[0114] The functional film is more preferably a film including electronic components such as a light control film or a display element film, and even more preferably a light control film or a display element film. That is, the functional layer is preferably at least one selected from the group consisting of a light control film and a display element film.

[0115] Typically, films equipped with electronic components tend to deteriorate or lose their functionality when autoclaved under high-temperature and high-pressure conditions. GHLC films, in particular, are prone to deterioration or loss of functionality when autoclaved under high-temperature and high-pressure conditions. Furthermore, thermal shrinkage due to pressure and temperature changes during pressure bonding can cause color unevenness in the resulting laminated glass structure, making it unsuitable for practical use. However, by using the interlayer film for laminated glass of the present disclosure, laminated glass structures can be suitably produced even by autoclaving at low temperatures, and functional layers such as GHLC films can be incorporated into the laminated glass structure without being deactivated. Therefore, laminated glass structures equipped with the laminated film of the present disclosure can effectively exhibit the functions inherent in the functional layer and sufficiently suppress the occurrence of color unevenness. Furthermore, films equipped with electronic components are prone to complex steps (thickness differences) due to the presence of electronic wiring, shielding printed portions, etc., which can easily result in residual air or bubbles between the interlayer film and the glass plate or functional layer during pressure bonding. However, in the present disclosure, even when pressure bonding is performed at low temperatures, the generation of residual air and foaming are sufficiently suppressed, and the resulting laminated glass structure has excellent transparency and a good appearance. Furthermore, a laminated glass structure (for example, window glass) incorporating a light control film or a display element film has high added value, such as excellent design properties.

[0116] A light control film is a film-like component equipped with a light control element. Specifically, a light control film preferably comprises two resin films and a light control layer disposed between the two resin films. A light control film having such a configuration has resin materials on the surfaces that contact the first interlayer film and the second interlayer film, which can improve adhesion to these interlayer films.

[0117] The resin film used in the light-control film is not particularly limited, but examples thereof include polyester resin films such as polyethylene terephthalate (PET) film and polyethylene naphthalate (PEN) film; (meth)acrylic resin film; triacetyl cellulose (TAC) film; polyethersulfone (PES) resin film; polyimide resin film; etc. Among these, from the viewpoint of ease of handling, the resin film is preferably a polyester resin film, and more preferably a PET film. Each of the two resin films may have a conductive layer that forms an electrode on the surface facing the light-control layer.

[0118] The light-controlling layer changes its visible light transmittance by switching between the application and non-application of a voltage between the conductive layers provided on each of the two resin films. Preferred examples of the light-controlling layer include liquid crystal layers such as polymer-dispersed liquid crystal (PDLC) and guest-host crystal (GHLC); suspended particle device (SPD) layers containing a resin matrix and a light-controlling suspension dispersed therein; electrochromic material layers; and electrophoretic layers containing electrophoretic particles and a dispersant for dispersing the electrophoretic particles. Therefore, the light-controlling film preferably includes at least one material selected from the group consisting of PDLC, GHLC, SPD, electrochromic devices, and electrophoretic film devices. In other words, the functional layer preferably includes at least one material selected from the group consisting of PDLC films, GHLC films, SPD films, electrochromic films, and electrophoretic film devices.

[0119] The display element film is a film-like member including a display element. Specifically, the display element film preferably includes a resin film and a display element mounted on the resin film, and more preferably includes two resin films and a display element disposed between the two resin films. A display element film having such a configuration can have improved adhesion to the first interlayer film and the second interlayer film. Note that the resin film used in the display element film can be appropriately selected from the resin films described above with respect to the light control film. Furthermore, the resin film constituting the display element film may be provided with a conductive layer constituting an electrode on the surface facing the display element.

[0120] The film having electronic components is not limited to a light control film or a display element film, but may be other functional films. In other functional films, the electronic components may be mounted on the resin film in the same manner as in the light control film and the display element film, but a preferred embodiment is one in which the electronic components are disposed between a pair of resin films.

[0121] Here, a GHLC film is a film-like member comprising a GHLC (Guest-Host Liquid Crystal). Specifically, the GHLC film preferably comprises two resin films and a GHLC layer disposed between the two resin films. The GHLC layer is composed of, for example, a liquid crystal composition in which a dichroic dye is dissolved as a guest in a liquid crystal host. The dichroic dye has a single light absorption axis and absorbs only light vibrating in the direction of the light absorption axis. Therefore, a GHLC film comprising a GHLC layer can change the orientation of the dichroic dye in accordance with the movement of the liquid crystal due to an electric field, thereby controlling the direction of the light absorption axis and thereby changing the transmission state of the liquid crystal layer.

[0122] When a GHLC film is used as the functional layer in the laminated film, a spacer may be disposed between the two resin films constituting the GHLC film to control the thickness (cell gap) of the GHLC layer. The spacer is not particularly limited, and may be, for example, a bead spacer or a spacer formed from photoresist into, for example, a cylindrical shape. The shape of the spacer is not particularly limited, and may be, for example, a spherical shape, a cylindrical shape, or a prismatic shape.

[0123] The functional layer may also be a solar cell element. By using a solar cell element in the functional layer, the laminated glass structure of the present disclosure can provide laminated glass for building-integrated photovoltaics (BIPV). The solar cell element is not particularly limited as long as it is a solar cell element used in BIPV, and examples thereof include crystalline or thin-film silicon solar cell elements; compound semiconductor solar cell elements such as CIS, CIGS, CdTe, and GaAs; and organic solar cell elements such as dye-sensitized, organic thin-film, and perovskite solar cells.

[0124] The laminated film can be produced by, for example, thermocompression bonding a first interlayer film, a functional layer, and a second interlayer film. When incorporating the laminated film into a laminated glass structure, the thermocompression bonding may be performed by first thermocompression bonding the first interlayer film, the functional layer, and the second interlayer film to form a laminated film, and then pressing the laminated film to a glass plate to form a laminated glass structure. Alternatively, the first interlayer film, the functional layer, and the second interlayer film before pressing may be disposed between two glass plates, and when pressing the glass plate and the laminated film together, the first interlayer film, the functional layer, and the second interlayer film may also be pressed together.

[0125] [Laminated Glass Structure] The laminated glass structure according to the present disclosure has a structure in which the laminated film according to the present disclosure described above is sandwiched between a pair of glass plates. For example, the laminated glass structure includes a first glass plate, a first interlayer film, a functional layer, a second interlayer film, and a second glass plate, in this order. The laminated glass structure may further include one or more optional layers between the respective layers, or may include two or more functional layers as described below.

[0126] (glass plate) The laminated glass structure has a first glass plate and a second glass plate. Each glass plate may be, for example, inorganic glass or organic glass, but is preferably inorganic glass. The first glass plate and the second glass plate may be made of the same material or different materials. For example, one of the first glass plate and the second glass plate may be inorganic glass and the other may be organic glass, but it is preferable that both the first glass plate and the second glass plate are inorganic glass or organic glass.

[0127] The inorganic glass is not particularly limited, but examples thereof include clear glass, float glass, tempered glass, colored glass, polished glass, patterned glass, wired glass, lined glass, ultraviolet absorbing glass, infrared reflecting glass, infrared absorbing glass, and green glass.

[0128] As the organic glass, what is generally called resin glass is used, and examples thereof include various organic glass plates such as polycarbonate plate, (meth)acrylic plate such as polymethyl methacrylate plate, acrylonitrile styrene copolymer plate, acrylonitrile butadiene styrene copolymer plate, polyester plate such as polyethylene terephthalate plate, fluorine-based resin plate, polyvinyl chloride plate, chlorinated polyvinyl chloride plate, polypropylene plate, polystyrene plate, polysulfone plate, epoxy resin plate, phenolic resin plate, unsaturated polyester resin plate, polyimide resin plate, etc. The resin plate may be subjected to a surface treatment or the like as appropriate.

[0129] The thickness of each glass plate is not particularly limited, but is preferably about 0.1 to 15 mm, more preferably 0.5 to 5 mm, and the thickness of each glass plate may be the same as or different from that of the first glass plate and the second glass plate.

[0130] Other members may be attached to each glass plate as necessary. For example, a functional member may be attached to at least one of the first and second glass plates, imparting various functions to the glass plate. The other members are preferably members constituting electronic devices or optical components, and more preferably members constituting display devices. Examples of display devices include liquid crystal display devices, organic EL display devices, LED display devices, and segment display devices, among which liquid crystal display devices are preferred. Examples of display devices include display panels using a glass plate as a substrate on which a display layer such as a liquid crystal layer or an organic EL layer, and light-emitting elements, etc. are provided. The glass plate as a substrate may be used as the first glass plate and / or the second glass plate. Each glass plate may also be laminated with various functional layers, such as a functional film (described below); a conductive layer constituting an electrode, sensor, etc.; an antireflection layer; or a hard coat layer.

[0131] (Layer composition) A laminated glass structure includes a pair of glass sheets (i.e., a first glass sheet and a second glass sheet) and a pair of interlayer films (i.e., a first interlayer film and a second interlayer film) sandwiching a functional layer between them. For example, it is preferable that the first interlayer film is adhered to the first glass sheet and the functional layer, and the second interlayer film is adhered to the second glass sheet and the functional layer, and thus bond these together. This results in a unified structure of the pair of glass sheets, the pair of interlayer films, and the functional layer. The layer structure of this embodiment is represented by G1 / F1 / Z / F2 / G2 (see FIG. 1 ). G1 represents the first glass sheet, G2 represents the second glass sheet, F1 represents the first interlayer film, F2 represents the second interlayer film, and Z represents the functional layer. FIG. 1 is a schematic diagram showing an example of the layer structure of a laminated glass structure.

[0132] Although the above example illustrates an embodiment in which two interlayer films and one functional layer are provided between a pair of glass sheets, three or more interlayer films and two or more functional layers may be provided between the pair of glass sheets. In this case, it is preferable that the interlayer films and functional layers are alternately arranged, and it is preferable that an interlayer film is provided at the position closest to each glass sheet. For example, when three or more interlayer films and two or more functional layers are provided between a pair of glass sheets, the layer structure of the laminated glass structure is preferably G1 / F3 / Z1 / F4 / Z2 / F5 / G2. Z1 and Z2 may be the same or different and represent functional layers. F3, F4, and F5 may be the same or different and represent interlayer films. At least one of the interlayer films F3, F4, and F5 is an interlayer film for laminated glass according to the present disclosure.

[0133] [Method for producing laminated glass structure] The laminated glass structure of the present disclosure is preferably produced by a method in which the above-described laminated film is placed between a pair of glass plates and bonded together by pressure to obtain a laminated glass structure. As described above, the use of the first interlayer film sufficiently prevents peeling at the layer interface, and the formation of residual air or bubbles. In the above-described production method, it is also possible to produce the laminated glass structure by pressure bonding the glass plates and the laminated film without disposing a gap filler on the periphery of the functional layer.

[0134] In the above manufacturing method, first, a first glass plate, a second glass plate, and the laminate film or each member constituting the laminate film (each interlayer film and functional layer) to be disposed between these glass plates are prepared.

[0135] As described above, a functional member may be attached to at least one of the first glass plate and the second glass plate. However, it is preferable that the functional member is attached to the glass plate before it is integrated into the laminated glass structure. Therefore, a glass plate having a functional member attached thereto may be prepared as at least one of the first glass plate and the second glass plate used in the above-mentioned manufacturing method. For example, as described above, when the glass plate constitutes a substrate of a display device, a display device may be prepared as at least one of the first glass plate and the second glass plate.

[0136] In the above-mentioned manufacturing method, it is preferable to next place the laminate film between a first glass plate and a second glass plate and bond them together to form an integrated laminated glass structure. It is also preferable to place each component constituting the laminate film (i.e., each interlayer film and functional layer) between the first glass plate and the second glass plate and bond them together to form an integrated laminated glass structure incorporating the laminate film. Here, each component constituting the laminate film may be arranged according to the layer structure of the resulting laminated glass structure. For example, the first interlayer film, the functional layer, and the second interlayer film may be arranged in this order between the first glass plate and the second glass plate.

[0137] The lamination (also referred to as lamination or main lamination) may be performed in a two-stage process of preliminary lamination followed by main lamination, or in one stage, but two stages are preferred. The preliminary lamination may be performed using a vacuum bag, a ring bag, a nipper roll, or a press other than these. The main lamination is preferably performed in an autoclave, but may also be performed using other presses. When laminating in one stage, lamination is preferably performed using a vacuum bag or a ring bag, but may also be performed using other presses.

[0138] In the above-described manufacturing method, the lamination may be performed at a low temperature depending on the heat resistance of the functional layer. Because the interlayer film for laminated glass according to the present disclosure has excellent fluidity, the resulting laminated glass structure can exhibit high safety even when produced by lamination at a low temperature or low pressure. By performing the lamination at a low temperature or low pressure, deterioration or deactivation of the functional layer is sufficiently prevented. Furthermore, even when a functional member or the like is attached to the glass plate, deterioration or deactivation of the member is sufficiently prevented.

[0139] From the viewpoint of more reliably preventing deterioration or deactivation of the functional layer, etc., the temperature during lamination is preferably 110° C. or lower, more preferably 100° C. or lower. Furthermore, from the viewpoint of more reliably preventing the generation of residual air and foaming, the temperature during lamination is preferably 60° C. or higher, more preferably 70° C. or higher.

[0140] Similarly, the pressure when performing the lamination is preferably 1.2 MPa or less, more preferably 0.8 MPa or less, from the viewpoint of more reliably preventing deterioration or deactivation of the functional layer, etc. The lower limit of the pressure when performing the lamination is not particularly limited, but when performing the lamination under pressure, for example, in an autoclave, the pressure is preferably 0.05 MPa or more, more preferably 0.1 MPa or more.

[0141] The time for which lamination is carried out at the above temperature and / or pressure is not particularly limited, but is preferably 1 to 120 minutes, and more preferably 5 to 60 minutes.

[0142] In the above manufacturing method, it is preferable to perform preliminary bonding (also referred to as preliminary lamination or temporary pressure bonding) before the lamination, as described above, which can sufficiently suppress a decrease in transmittance and adhesive strength that may occur during the autoclave process under low-temperature conditions.

[0143] Depending on the type of functional layer, etc., the preliminary bonding may be performed under low temperature conditions, or under low temperature and low pressure conditions, in order to further prevent deterioration or deactivation. In this case, for example, the temperature during preliminary bonding is preferably 110°C or lower, more preferably 100°C or lower. Furthermore, in order to further prevent the generation of residual air and foaming, the temperature during preliminary bonding is preferably 60°C or higher, more preferably 70°C or higher. The pressure during preliminary bonding is preferably 0.6 MPa or lower. Furthermore, when preliminary bonding is performed under negative pressure, such as when using a vacuum bag, the pressure during preliminary bonding is preferably 0.3 MPa or lower, more preferably 0.095 MPa or lower, and even more preferably 0.09 MPa or lower. The pressure during preliminary bonding under pressure is also preferably 0.01 MPa or higher, more preferably 0.05 MPa or higher.

[0144] The time for which preliminary bonding is carried out at the above temperature and / or pressure is not particularly limited, but is preferably 0 to 60 minutes, and more preferably 0 to 30 minutes, for example.

[0145] (Application) The laminated glass structure of the present disclosure can be used in a wide variety of applications. For example, the laminated glass structure of the present disclosure is used as window glass for vehicles such as automobiles and trains, various vehicles such as ships and airplanes, various buildings such as buildings, condominiums, detached houses, halls, and gymnasiums, machine tools for cutting and polishing, construction machinery such as shovels and cranes, and partitions inside various vehicles and buildings. Among these, the laminated glass structure is preferably used for vehicles such as automobiles and trains, or for buildings. Thus, both laminated glass for vehicles and laminated glass for buildings composed of the laminated glass structure of the present disclosure have been discovered by the present inventors. The laminated glass structure is particularly preferably used as window glass for vehicles or BIPV, and is particularly preferably used as window glass for vehicles. The window glass for vehicles is preferably the windshield, side glass, rear glass, or roof glass of an automobile or train.

[0146] The laminated glass structure of the present disclosure is also preferably used for various display applications. For example, window glass, partitions, etc. using the laminated glass structure may be used as displays. The laminated glass structure of the present disclosure can also be used as cover glass, etc. for various displays. For example, the laminated glass structure may be applied to in-vehicle displays, etc. [Example]

[0147] The present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass." The weight-average molecular weight of the resin, the Tg of the film, and the creep compliance at 90°C per film layer were determined according to the methods described above. The exposed area of ​​the film was also determined according to the method described above (clear glass (product name: "Float Plate Glass") manufactured by Sanshiba Glass Materials Co., Ltd. was used as the float plate glass, and image capture and image analysis were performed under the conditions described above).

[0148] <Materials, etc.> The materials or components used in the preparation examples are as follows: (1) Glass plate Clear glass manufactured by Sanshiba Glass Co., Ltd. (product name: "float plate glass"), 3 mm thick

[0149] (2)Thermoplastic resin Preparation Example A1 (Resin 1) A reactor equipped with a stirrer was charged with 1800 ml of ion-exchanged water, 150 g of polyvinyl alcohol A (average degree of polymerization 1700, degree of saponification 99 mol%), and 50 g of polyvinyl alcohol B (average degree of polymerization 800, degree of saponification 99 mol%). The mixture was heated and dissolved with stirring to obtain a polyvinyl alcohol solution. The solution was then cooled and adjusted to 40°C. 30% hydrochloric acid was added as a catalyst to a hydrochloric acid concentration of 0.9% by mass. The temperature was then adjusted to 20°C. Then, n-butyl aldehyde was added with stirring to a concentration of 15 mol%. The solution was then adjusted to 13°C, and n-butyl aldehyde was added to a concentration of 54.7 mol%, resulting in the precipitation of a white granular polyvinyl butyral resin. 20 minutes after the second addition of n-butyl aldehyde, 30% hydrochloric acid was added to a hydrochloric acid concentration of 1.1% by mass. The temperature was then raised to 48°C, and the mixture was aged at this aging temperature for 2 hours. Next, the solution was cooled and neutralized, and then the polyvinyl butyral resin was washed with water and dried to obtain Resin 1 (polyvinyl butyral resin, hydroxyl group content 30.9 mol%, acetalization degree 68.1 mol%, acetylation degree 0.99 mol%, weight average molecular weight 245,000).

[0150] Preparation example A2 (resin 2) A reactor equipped with a stirrer was charged with 1800 ml of ion-exchanged water and 200 g of polyvinyl alcohol A (average degree of polymerization 1700, degree of saponification 99 mol%), and the mixture was heated and dissolved while stirring to obtain a polyvinyl alcohol solution. Next, 30% hydrochloric acid was added as a catalyst to this solution so that the hydrochloric acid concentration was 0.2% by mass. The temperature was then adjusted to 15°C, and n-butyl aldehyde was added to 10 mol% while stirring. Subsequently, n-butyl aldehyde was added to 60 mol%, resulting in the precipitation of a white granular polyvinyl butyral resin. Ten minutes after the precipitation, 30% hydrochloric acid was added so that the hydrochloric acid concentration was 1.8% by mass. The temperature was then raised to 53°C, and the mixture was aged at this aging temperature for 2 hours. Next, the solution was cooled and neutralized, and then the polyvinyl butyral resin was washed with water and dried to obtain Resin 2 (polyvinyl butyral resin, hydroxyl group content 31.5 mol%, acetalization degree 67.8 mol%, acetylation degree 0.7 mol%, weight average molecular weight 267,000).

[0151] Preparation Example A3 (Resin 3) Resin 3 (polyvinyl butyral resin, hydroxyl group content 30.1 mol%, acetalization degree 69.2 mol%, acetylation degree 0.67 mol%, weight average molecular weight 262,000) was obtained in the same manner as Resin 1, except for the aging temperature of 53°C for 2 hours at 63°C.

[0152] (3) Plasticizer 3GO: Triethylene glycol-bis-(2-ethylhexanoate), manufactured by Sekisui Chemical Co., Ltd., molecular weight 402

[0153] (4) Interlayer film for laminated glass Preparation example B1 (membrane 1) A resin composition was obtained by mixing 40 parts of plasticizer (3GO) with 100 parts of resin 1. The obtained resin composition was fed to a twin-screw extruder and embossed using an embossing roll. A film-like membrane 1 with a thickness of 760 μm was produced. The obtained membrane 1 was measured for exposed membrane area, Tg, creep compliance J(t) at 90°C, and surface roughness (RzJIS94, Rc). The results are shown in Table 1.

[0154] Preparation example B2 (membrane 2) A film-like membrane 2 having a thickness of 760 μm was prepared in the same manner as in Preparation Example B1, except that resin 2 was used instead of resin 1. The exposed membrane area, Tg, creep compliance J(t) at 90°C, and surface roughness (RzJIS94, Rc) of the obtained membrane 2 were measured. The results are shown in Table 1.

[0155] Preparation example B3 (membrane 3) A film-like membrane 3 having a thickness of 760 μm was prepared in the same manner as in Preparation Example B1, except that resin 3 was used instead of resin 1. The exposed membrane area, Tg, creep compliance J(t) at 90°C, and surface roughness (RzJIS94, Rc) of the obtained membrane 3 were measured. The results are shown in Table 1.

[0156] (5) Evaluation test Using samples measuring 30 cm long x 30 cm wide cut from each of the films obtained above, laminated glass was produced as follows, and an impact resistance test was carried out. The results are shown in Table 1.

[0157] <Making laminated glass> Each sample was maintained at a constant temperature of 23°C and 28% RH for 4 hours. Two float glass sheets measuring 30 cm long, 30 cm wide, and 3 mm thick, conforming to JIS R3202 (2011), were separately prepared. The glass and the sample were then laminated so that the tin side of the glass contacted the sample and the sample was positioned between the two sheets of glass. The resulting laminate was pre-pressed using a heated roll at 170°C. The pre-pressed laminate was placed in an autoclave and heated to 90°C at 2°C / min. When the temperature reached 40°C during heating, the pressure was reduced to 0.1 MPa. After reaching 90°C, the temperature was maintained for 20 minutes and then cooled at 2°C / min. When the temperature reached 40°C, the pressure was returned to normal pressure. In this manner, laminated glass was produced.

[0158] <Impact resistance test> Using each of the laminated glasses prepared as described above, an impact resistance test was carried out at -20°C in accordance with JIS R3212 (1998). The presence or absence of penetration in the impact resistance test was checked, and cases where there was no penetration were rated as "Good", and cases where there was penetration were rated as "Poor". Furthermore, when there was no penetration (rated as "Good"), the size of the area where the film peeled off at the part of the impact surface where the steel ball fell was measured, and the evaluation was made according to the following criteria. ◎: No peeling ○: The size of the peeled area is less than 1 cm ×: Peeling area is 1cm or larger

[0159] [Table 1] [Explanation of symbols]

[0160] 10: Laminated glass structure G1, G2: Glass plates F1, F2: Intermediate film Z: Functional layer

Claims

1. An interlayer film for laminated glass, comprising a polyvinyl acetal resin, and having an exposed area of ​​the film calculated by the following method of 90 area % or less. <Calculation method for exposed membrane area> As a sample, one sheet of interlayer film for laminated glass measuring 30 cm in length and 15 cm in width was prepared and kept at constant temperature conditions of 23°C and 28% RH for 4 hours. Separately, two sheets of float glass measuring 30 cm in length, 15 cm in width, and 3 mm in thickness, conforming to JIS R3202 (2011), were prepared. The glass and the sample were then laminated so that the tin side of the glass contacted the sample and the sample was positioned between the two sheets of glass. The resulting laminate was pre-pressed using a heated roll at 170°C. The pre-pressed laminate was placed in an autoclave and heated to 90°C at 2°C / min. During heating, the pressure was reduced to 0.1 MPa when the temperature reached 40°C. After reaching 90°C, the temperature is maintained for 20 minutes and then lowered at a rate of 2°C / min. When the temperature has lowered to 40°C, the pressure is returned to normal pressure. The obtained optical laminate is allowed to stand for 16 hours in an environment at a temperature of -18°C±0.6°C, and then the optical laminate, fixed at an inclination angle of 45 degrees, is struck 72 times per minute with a hammer whose spring screw is adjusted so that the impact force at the top dead center of the stroke is 10.5±0.5 kg. The impact is performed so that the hammer strikes the optical laminate horizontally. The impact is applied from the bottom of the optical laminate 13 times at 11.5 mm intervals in the horizontal direction (stroke 150 mm) and 10 times at 9 mm intervals in the vertical direction (stroke 90 mm), for a total of 130 times. After the impact, an image of the optical laminate is taken, and the exposed film area (area %) of the sample where the glass has peeled off from the optical laminate and is exposed is analyzed.

2. The polyvinyl acetal resin has a weight average molecular weight of 220,000 to 310,000. The interlayer film for laminated glass according to claim 1 .

3. Further containing a plasticizer The interlayer film for laminated glass according to claim 1 .

4. The plasticizer is at least one selected from the group consisting of triethylene glycol-di-2-ethylhexanoate, polyoxyethylene polyoxypropylene glycol, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, and derivatives thereof in which some of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups. The interlayer film for laminated glass according to claim 3 .

5. Creep compliance per layer at 90°C is 6.0 x 10 －５ Pa －１ That's all The interlayer film for laminated glass according to claim 1 .

6. At least one surface of the interlayer film for laminated glass has an uneven shape. The interlayer film for laminated glass according to claim 1 .

7. A laminated structure comprising the interlayer film for laminated glass according to any one of claims 1 to 6 and a functional layer. A laminated film characterized by:

8. The functional layer is sandwiched between a first interlayer film and a second interlayer film, At least one of the first interlayer film and the second interlayer film is the interlayer film for laminated glass according to any one of claims 1 to 6. The laminated film according to claim 7 .

9. The functional layer is at least one selected from the group consisting of a light control film, a display element film, and a solar cell element. The laminated film according to claim 7 .

10. the functional layer is a light control film, The light management film comprises at least one selected from the group consisting of a polymer dispersed liquid crystal (PDLC), a guest host liquid crystal (GHLC), a suspended particle device (SPD), an electrochemical device, and an electrophoretic film device. The laminated film according to claim 7 .

11. A structure in which the laminated film according to claim 7 is sandwiched between a pair of glass plates. A laminated glass structure characterized by:

12. Fabricated without gap filler 12. The laminated glass structure according to claim 11.

Images