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

Abstract

The present disclosure provides an interlayer film for laminated glass that is excellent in adhesiveness to various adherends, gives a laminated glass structure 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 means】An interlayer film for laminated glass that contains a polyvinyl acetal resin, has an uneven shape on at least one surface, and has an embossing remaining distance calculated by a predetermined method of less than 27 mm.

Description

Technical Field

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

Background Art

[0002] Conventionally, a laminated glass structure in which an interlayer film is interposed between two glass plates and integrated is widely known. Since the laminated glass structure is safe because glass fragments are less likely to scatter even when it is damaged by an external impact, it is widely used in vehicles such as automobiles, aircraft, ships, and buildings.

[0003] In recent years, there has been a demand for imparting various functions to the laminated glass structure. For example, a functional layer such as a dimming film may be disposed between two glass plates. Patent Document 1 discloses a laminated glass including an interlayer film and a dimming element encapsulated in the interlayer film between two glass plates.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A laminated glass structure is generally manufactured by placing an intermediate film between two glass plates and subjecting the glass plates and the intermediate film to an autoclave process in which they are pressed together under high temperature and high pressure conditions such as a temperature of about 130 to 140°C and a pressure of about 1.3 MPa after a preliminary degassing process. However, when a functional layer such as a dimming film is further placed between the two glass plates, complicated steps (thickness differences) are likely to occur because electronic wiring, shielding printing portions, etc. are provided in the functional layer, and pressure unevenness is also likely to occur during pressing. Therefore, air remains or foams between the intermediate film and the glass plate or the functional layer during pressing, resulting in insufficient transparency in the obtained laminated glass structure, distortion or wrinkles in the functional layer, and the appearance of the obtained laminated glass structure not being good.

[0006] In a laminated glass structure including a functional layer such as a dimming film, a frame-shaped intermediate layer (also referred to as a gap filler) is disposed around the functional layer for the purpose of protecting the end portion of the functional layer from the external environment, and a structure in which this is sandwiched between a pair of intermediate layers and further sandwiched between a pair of glass plates is generally adopted (see, for example, Patent Document 1, etc.). If a laminated glass structure including a functional layer is manufactured without using a gap filler from the viewpoint of improving work efficiency, etc., air may remain or foam, and not only a good appearance cannot be obtained in the laminated glass structure, but there are also concerns such as the impact resistance being likely to be lower than when a gap filler is used.

[0007] The present disclosure has been made in view of the above situation, and an object thereof is to provide an intermediate film for laminated glass that is excellent in adhesiveness to various adherends, has a good appearance, and can suitably provide a highly safe laminated glass structure. Another object of the present disclosure is also to provide a laminated film and a laminated glass structure using such an intermediate film for laminated glass.

Means for Solving the Problems

[0008] In the course of various studies on interlayer films for laminated glass, the inventors have found that when the interlayer film for laminated glass contains a polyvinyl acetal resin and the emboss remaining distance calculated by a predetermined method is within a predetermined range, the adhesiveness to various adherends such as glass plates is high. By using such an interlayer film for laminated glass, it is possible to efficiently obtain a laminated glass structure having a good appearance by suppressing the remaining air and foaming during pressure bonding with a glass plate or the like without passing through an autoclave process under high temperature and high pressure conditions or without using a gap filler. Further, when a functional layer is laminated on the interlayer film for laminated glass to obtain a laminated glass structure, the laminated glass structure can effectively exhibit the effects derived from the functional layer. Thus, the inventors have completed the interlayer film for laminated glass and the like of the present disclosure. That is, the present disclosure relates to the following interlayer film for laminated glass.

[0009] The present disclosure 1 is an interlayer film for laminated glass that contains a polyvinyl acetal resin, has an uneven shape on at least one surface, and has an emboss remaining distance calculated by the following method of less than 27 mm. <Method for calculating emboss remaining distance> Prepare two float glass plates with a length of 300 mm, a width of 300 mm, and a thickness of 3 mm and conforming to JIS R3202 (2011), and further prepare two interlayer films for laminated glass with a length of 300 mm, a width of 300 mm, and a thickness of 760 μm, and one polyethylene terephthalate (PET) film with a length of 200 mm, a width of 200 mm, and a thickness of 188 μm. After that, laminate the float glass plate, the interlayer film for laminated glass, the PET film, the interlayer film for laminated glass, and the float glass plate in this order and so that the centroid of each member coincides in plan view. Degas the obtained laminate (referred to as laminate 1) at a vacuum degree of 4 kPa for 5 minutes. When measuring the transmittance (referred to as transmittance B) from the end of the laminate 1 toward the end opposite to the end along the center line passing through the centroid of the PET film when the laminate 1 after degassing is viewed in plan view, the ratio of the following transmittance A to the transmittance B ( B / A) Measure the distance between the first part where [ becomes 0.75 or less for the first time and the end part of the region where the PET film is disposed and close to the first part, and set this distance as the embossing remaining distance. The transmittance A is the maximum value of the transmittance of the following laminate 3. Prepare two sheets each of the same float plate glass and the interlayer film for laminated glass used when obtaining the above laminate 1. Then, laminate the float plate glass, the interlayer film for laminated glass, the interlayer film for laminated glass, and the float plate glass in this order and so that the centroid of each member coincides in plan view. Put this laminate (referred to as laminate 2) into a vacuum laminator "LAMINATOR 0505S" manufactured by Nisshinbo Mechatronics Inc., and degas for 5 minutes at a vacuum degree of 4 kPa. Then, while maintaining the degassed state, apply pressure up to 100 kPa to the above laminate 2 at a medium speed press (pressure increase rate: 2 kPa / s), and then hold at 100 kPa for 3 minutes. Then, perform pressure bonding for 20 minutes using an autoclave under the conditions of 140 °C and 1.3 MPa to obtain laminate 3.

[0010] The present disclosure 2 is the interlayer film for laminated glass of the present disclosure 1, wherein the polyvinyl acetal resin has a weight average molecular weight of 220,000 to 310,000. The present disclosure 3 is the interlayer film for laminated glass of the present disclosure 1 or 2, further containing a plasticizer. The present disclosure 4 is the interlayer film for laminated glass of the present 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 in which a part of the hydrogen atoms of the terminal hydroxyl groups thereof are substituted with alkyl groups. The present disclosure 5 is the interlayer film for laminated glass according to any one of the present disclosures 1 to 4, wherein at least one surface has an uneven shape, the surface roughness (RzJIS94) measured in accordance with JIS B0601 (1994) of the surface having the uneven shape is 10 to 80 μm, and the surface roughness (Rc) measured in accordance with JIS B0601 (2013) of the surface having the uneven shape is 10 to 40 μm. The present disclosure 6 is a laminated film having a structure in which an interlayer film for laminated glass according to any one of the present disclosures 1 to 5 and a functional layer are laminated. The present disclosure 7 is a laminated film according to the present disclosure 6, 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 the present disclosures 1 to 5. The present disclosure 8 is a laminated film according to the present disclosure 6 or 7, wherein the functional layer is at least one selected from the group consisting of a dimming film and a display element film. The present disclosure 9 is a laminated film according to any one of the present disclosures 6 to 8, wherein the functional layer is a dimming film, and the dimming film includes at least one selected from the group consisting of polymer dispersed liquid crystal (PDLC), guest host liquid crystal (GHLC), suspended particle device (SPD), electrochromic device, and electrophoretic film device. The present disclosure 10 is a laminated glass structure having a structure in which a laminated film according to any one of the present disclosures 6 to 9 is sandwiched between a pair of glass plates.

Advantages of the Invention

[0011] According to the present disclosure, it is possible to provide an interlayer film for laminated glass that is excellent in adhesiveness to various adherends, has a good appearance, and can suitably provide a highly safe laminated glass structure. Further, according to the present disclosure, it is also possible to provide a laminated film and a laminated glass structure using such an interlayer film for laminated glass.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0013] 〔Interlayer Film for Laminated Glass〕 The interlayer film for laminated glass of the present disclosure contains a polyvinyl acetal resin, at least one surface thereof has an uneven shape, and the emboss remaining distance calculated by the above-described method is 30 mm or less. Here, when measuring the transmittance along the above center line, the transmittance of a portion having a width of 5 mm centered on the above center line in a plan view is measured (see, for example, FIG. 4 described later). In addition, for the measurement of the transmittance, a glass transmittance measuring device “MJ-TM110 (separate sensor type)” (Sato Shoji) is used.

[0014] The interlayer film for laminated glass containing a polyvinyl acetal resin, having an uneven shape on at least one surface, and having an emboss remaining distance within a predetermined range has high adhesiveness to various adherends such as glass plates. Therefore, by using the interlayer film for laminated glass, air remaining and foaming during pressure bonding with a glass plate or the like can be suppressed without going through an autoclave process under high temperature and high pressure conditions or without using a gap filler, and a laminated glass structure having a good appearance can be efficiently obtained. Further, when a functional layer is laminated on the interlayer film for laminated glass to obtain a laminated glass structure, the effects derived from the functional layer can be effectively exhibited. From the viewpoint of further exerting these effects, the emboss remaining distance is more preferably 26 mm or less, and even more preferably 25 mm or less.

[0015] Here, for example, by appropriately adjusting the amount of hydroxyl groups contained in the polyvinyl acetal resin, the weight average molecular weight of the polyvinyl acetal resin, the stereoregularity, the surface roughness of the interlayer film for laminated glass, etc., the emboss remaining distance can be easily adjusted within the above range.

[0016] The interlayer film for laminated glass may be a single-layer film having a single-layer structure or a multi-layer film having a multi-layer structure. When the interlayer film for laminated glass has a plurality of layers, the plurality of layers may have the same configuration as each other or different configurations. For example, in the plurality of layers, the types of materials constituting the film (e.g., thermoplastic resin) and their contents may be the same as each other or different. When the interlayer film for laminated glass is a multi-layer film, when the entire multi-layer film is used as a sample in the above method, it is preferable that the emboss remaining distance is within the above range.

[0017] The interlayer film for laminated glass preferably has a creep compliance at 90 °C of 6.0×10 -5 Pa -1 or more per layer. Since such an interlayer film has high fluidity under bonding conditions, for example, a laminated glass structure can be preferably provided 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 pressed, delamination of the layer interface, residual air, and foaming are sufficiently suppressed. Further, for example, even when this pressing is performed under low-temperature conditions, residual air and foaming are sufficiently suppressed. Further, for example, even when this pressing is performed under low-pressure conditions, residual air and foaming are sufficiently suppressed. Therefore, the obtained laminated glass structure can be more excellent in transparency and have a better appearance.

[0018] The above creep compliance is more preferably 8.0×10 -5 Pa -1 or more, still more preferably 1.0×10 -4 Pa -1 or more, and particularly preferably 1.3×10 -4 Pa -1 or more. The upper limit of the above creep compliance is preferably 1.0×10 -3 Pa -1 or less, more preferably 7.0×10 -4 Pa -1 or less, and still more preferably 5.0×10 -4 Pa -1The following are more preferable. In particular, the above creep compliance is 6.0×10 -5 Pa -1 or more and preferably 1.0×10 -3 Pa -1 or less, more preferably 6.0×10 -5 Pa -1 or more and even more preferably 7.0×10 -4 Pa -1 or less, still more preferably 6.0×10 -5 Pa -1 or more and yet more preferably 5.0×10 -4 Pa -1 or less, particularly preferably 8.0×10 -5 Pa -1 or more and even more preferably 5.0×10 -4 Pa -1 or less, most preferably 1.0×10 -4 Pa -1 or more and particularly preferably 5.0×10 -4 Pa -1 or less, and most preferably 1.3×10 -4 Pa -1 or more and 5.0×10 -4 Pa -1 or less.

[0019] The creep compliance at 90°C per layer above is determined as follows. <Method for Measuring Creep Compliance> As a measuring device, a dynamic viscoelasticity measuring system "MCR702e MultiDrive" (purchased in 2023) manufactured by Anton Paar is used. Using this measuring device, a circular sample with a diameter of 8 mm and a thickness of 0.76 mm prepared from one layer of the intermediate film is subjected to a shear stress of 400 Pa at a measuring temperature of 90°C for 15 minutes to obtain the creep compliance J(t). The value at the 10-minute mark of the obtained creep compliance J(t) is taken as the value of the "creep compliance at 90°C per layer" above.

[0020] Here, when the thickness of the sample (interlayer film) to be measured is less than 0.76 mm, several such samples can be stacked and press-molded or the like to make the thickness of the samples uniform. If the physical properties of the sample change due to hot pressing, measurement can be performed at the original thickness without pressing. Also, when the thickness of the sample is greater than 0.76 mm, the thickness can be made uniform by press molding or the like, or measurement can be performed at the original thickness. From the perspective of measurement accuracy, the measured thickness of the sample is preferably 0.3 mm or more and preferably 3 mm or less.

[0021] When setting the sample in the measuring device, in order to sufficiently press-bond the sample and the jig, set the gap at room temperature to achieve a pressure of 5 - 10 N, and then heat to 140 °C with the gap fixed. Two minutes after reaching 140 °C, start cooling to the measurement temperature. After holding for 2 minutes after reaching the measurement temperature, start measuring the creep compliance. As the measuring jig, use a stainless-steel parallel plate with a diameter of 8 mm.

[0022] 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. Also, as described later, when the interlayer film for laminated glass is laminated on the 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 laminated glass structure 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.

[0023] The interlayer film for laminated glass preferably has a glass transition temperature (Tg) of -10°C or higher. When the Tg is within this range, the penetration resistance and impact resistance are further improved. The Tg is more preferably 0°C or higher, still more preferably 10°C or higher, and particularly preferably 15°C or higher. The Tg is also preferably 50°C or lower. When the Tg is within this range, the adhesiveness to a glass plate or the like is likely to be better. The Tg is more preferably 40°C or lower, still more preferably 30°C or lower.

[0024] The Tg of the interlayer film for laminated glass is determined by viscoelasticity measurement. Specifically, it is determined as follows, for example. <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%. Next, using a viscoelasticity measuring device "ARES-G2" manufactured by TA Instruments, the viscoelasticity is measured. A parallel plate with a diameter of 8 mm is used as the jig, and the measurement is carried out under the conditions of a shear mode, a temperature decrease rate of 3°C / min from 100°C to -20°C, and 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).

[0025] 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 adhesiveness to various adherends (for example, a functional layer, a glass plate, etc.), and by using this interlayer film, a laminated glass structure excellent in impact resistance and the like can be provided. Further, by adjusting the weight average molecular weight, the glass transition temperature of the resin, and / or the intermolecular interaction, etc. of the polyvinyl acetal resin used, it becomes easy to adjust the above-mentioned 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 above creep compliance value is the above resin layer. In addition, each component contained in the interlayer film for laminated glass may be used alone as only one kind, or two or more kinds may be used in combination. Hereinafter, the polyvinyl acetal resin will be described in detail.

[0026] The polyvinyl acetal resin is obtained by acetalizing polyvinyl alcohol with an aldehyde. Each raw material of the polyvinyl acetal resin may be used alone, or two or more of them may be used in combination.

[0027] The aldehyde is not particularly limited. For example, aldehydes having 1 to 10 carbon atoms are preferably used. The aldehydes having 1 to 10 carbon atoms are not particularly limited. For example, n-butyl aldehyde, isobutyl aldehyde, n-valeraldehyde, 2-ethylbutyl aldehyde, n-hexyl aldehyde, n-octyl aldehyde, n-nonyl aldehyde, n-decyl aldehyde, formaldehyde, acetaldehyde, and benzaldehyde can be mentioned. Among these, the above aldehyde is preferably n-butyl aldehyde, n-hexyl aldehyde, or n-valeraldehyde, and more preferably n-butyl aldehyde. Therefore, the polyvinyl acetal resin is preferably a polyvinyl butyral resin.

[0028] Polyvinyl alcohol can be obtained, for example, by saponifying a polyvinyl ester such as polyvinyl acetate. The saponification degree of polyvinyl alcohol is generally 70 to 99.9 mol%.

[0029] The average degree of polymerization of polyvinyl alcohol is preferably 1000 to 3000. By using such polyvinyl alcohol, the polyvinyl acetal resin is likely to have a preferable weight average molecular weight described later. The average degree of polymerization of polyvinyl alcohol is more preferably 1100 to 2500, still more preferably 1200 to 2000, and particularly preferably 1300 to 1700.

[0030] As the polyvinyl alcohol, two or more kinds of polyvinyl alcohol having different average degrees of polymerization may be used. In this case, it is preferable to produce the polyvinyl acetal resin using a mixture of two or more kinds of polyvinyl alcohol as a raw material.

[0031] When using two or more polyvinyl alcohols, for example, as the polyvinyl alcohol, it is preferable to use 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 from 1500 to 3500, more preferably from 1600 to 2500, and still more preferably from 1600 to 2000. Further, the average degree of polymerization of the second polyvinyl alcohol is preferably from 200 to 1200, more preferably from 300 to 900, and still more preferably from 400 to 850.

[0032] When the first polyvinyl alcohol and the second polyvinyl alcohol are used in combination, their blending ratios are not particularly limited. For example, based on 100% by mass of the total amount of the first polyvinyl alcohol and the second polyvinyl alcohol, the blending amount of the second polyvinyl alcohol is preferably 1 to 50% by mass, more preferably 3 to 40% by mass, still more preferably 5 to 35% by mass, and particularly preferably 10 to 30% by mass.

[0033] The average degree of polymerization of polyvinyl alcohol is determined by a method in accordance with JIS K6726 (1994) "Test Methods for Polyvinyl Alcohol". Further, when two or more polyvinyl alcohols 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.

[0034] The polyvinyl acetal resin preferably has a weight average molecular weight of 100,000 to 300,000. Thereby, the adhesiveness of the interlayer film to various adherends and the penetration resistance of the laminated glass structure are further improved. Further, by using a polyvinyl acetal resin having a weight average molecular weight within the above range, it becomes easier to adjust the creep compliance per layer of the interlayer film within the above-described range. The lower limit of the weight average molecular weight of the polyvinyl acetal resin is more preferably 180,000 or more, still 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, still more preferably 260,000 or less, and particularly preferably 250,000 or less. The range of the weight average molecular weight of the polyvinyl acetal resin is more preferably 180,000 to 280,000, still more preferably 210,000 to 260,000, and particularly preferably 220,000 to 250,000.

[0035] The weight average molecular weight of the polyvinyl acetal resin is determined, for example, by the following measuring method using gel permeation chromatography. <Method for Measuring Molecular Weight> Dissolve the polyvinyl acetal resin in an N-methyl-2-pyrrolidone solution containing lithium bromide so as to be 10 mM to obtain a solution having a polyvinyl acetal resin concentration of 0.05% by mass. After filtering the obtained solution using a syringe filter (manufactured by Merck, Millex-LH 0.45 μm), measure the molecular weight using gel permeation chromatography (manufactured by Waters, e2690). Then, calculate the weight average molecular weight (Mw) using the molecular weight calibration curve prepared with a monodisperse polystyrene standard sample. Note that Shodex GPC KF-806L (manufactured by Showa Denko KK) is used as the column, and an N-methyl-2-pyrrolidone solution containing lithium bromide so as to be 10 mM is used as the eluent.

[0036] The hydroxyl group content of the polyvinyl acetal resin is preferably 15 mol% or more. Thereby, the adhesiveness of the intermediate film to various adherends is likely to be good, and the obtained laminated glass structure is excellent in penetration resistance and the like. The hydroxyl group content of the polyvinyl acetal resin is preferably 38 mol% or less. Thereby, the flexibility of the intermediate film becomes good, and it is possible to prevent the obtained laminated glass structure from becoming too hard. Further, 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, and the high-temperature heat resistance of the intermediate film is further improved. The lower limit of the above hydroxyl group content is more preferably 20 mol% or more, and even more preferably 25 mol% or more. The upper limit of the above hydroxyl group content is more preferably 35% or less, and even more preferably 33 mol% or less.

[0037] When using polyvinyl butyral resin 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. 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.

[0038] The hydroxyl group content of the polyvinyl acetal resin is a value obtained by expressing as a percentage the mole fraction obtained by dividing the amount of ethylene groups to which hydroxyl groups are bonded by the total amount of ethylene groups in the main chain. The amount of ethylene groups to which hydroxyl groups are bonded can be measured, for example, in accordance with JIS K6728 (1977) "Test Methods for Polyvinyl Butyral".

[0039] The degree of acetalization of the polyvinyl acetal resin is preferably 47 mol% or more, more preferably 55 mol% or more, and still 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 still more preferably 75 mol% or less. When the acetal group is a butyral group and the polyvinyl acetal resin is a polyvinyl butyral resin, the degree of acetalization means the degree of butyralization.

[0040] The degree of acetalization of the polyvinyl acetal resin is a value obtained by dividing, by the total amount of ethylene groups in the main chain, the value obtained by subtracting the amount of ethylene groups to which a hydroxyl group is bonded and the amount of ethylene groups to which an acetyl group is bonded from the total amount of ethylene groups in the main chain, and expressing the resulting mole fraction as a percentage. The degree of acetalization can be calculated from the results measured by a method conforming to, for example, JIS K6728 (1977), "Test Methods for Polyvinyl Butyral".

[0041] The degree of acetylation of the polyvinyl acetal resin is preferably 30 mol% or less. Thereby, the moisture resistance of the interlayer film is improved. The upper limit of the degree of acetylation is more preferably 20 mol% or less, still 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, and more preferably 0.1 mol% or more.

[0042] The degree of acetylation of the polyvinyl acetal resin is a value obtained by dividing, by the total amount of ethylene groups in the main chain, the mole fraction obtained by dividing the amount of ethylene groups to which an acetyl group is bonded, and expressing the result as a percentage. The amount of ethylene groups to which an acetyl group is bonded can be measured, for example, in accordance with JIS K6728 (1977), "Test Methods for Polyvinyl Butyral".

[0043] The polyvinyl acetal resin is preferably an unmodified polyvinyl acetal resin, but a modified polyvinyl acetal resin may also be used. The modified polyvinyl acetal resin has a structure other than an acetal group, a hydroxyl group, and an acetyl group (modified group), and preferably has the modified group in the side chain. Examples of the modified group include those having a polyalkylene oxide structure in the side chain, those having an alkyl group other than an acetal group and an acetyl group (for example, having about 2 to 30 carbon atoms) in the side chain, and the like. The modification amount is not particularly limited, but is, for example, about 0.1 mol% or more and about 10 mol%. The modification amount represents the ratio of the functional group to all the vinyl monomer units constituting the polyvinyl acetal resin.

[0044] The interlayer film for laminated glass may further contain a thermoplastic resin other than the polyvinyl acetal resin. Examples of the thermoplastic resin other than the 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 preferable that the main component of the resin constituting the interlayer film for laminated glass is the polyvinyl acetal resin. Specifically, in 100% by mass of the total amount of the resin components constituting the resin layer of the interlayer film for laminated glass (when the interlayer film includes multiple resin layers, each resin layer), the polyvinyl acetal resin is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and most preferably 100% by mass. That is, it is most preferable that the resin constituting the interlayer film for laminated glass is only the polyvinyl acetal resin.

[0045] The polyvinyl acetal resin is preferably produced by a production method including, for example, a mixing step of mixing polyvinyl alcohol and an aldehyde, and an aging step of aging the mixture obtained in the mixing step. The acetalization of polyvinyl alcohol proceeds by the above mixing step and aging step, and thus a polyvinyl acetal resin is obtained. In addition, 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.

[0046] In the above mixing step, polyvinyl alcohol and an aldehyde may be mixed according to a conventional method. Further, a catalyst such as an acid catalyst for promoting the acetalization reaction may be added in addition to polyvinyl alcohol and an aldehyde. For example, an aldehyde may be added to a mixture obtained by adding an acid catalyst to polyvinyl alcohol under low temperature conditions of about 0 to 40°C. Further, when two or more kinds of polyvinyl alcohols are used in combination (for example, when two or more kinds of polyvinyl alcohols having different molecular weights are used), the two or more kinds of polyvinyl alcohols may be mixed with an aldehyde.

[0047] In the above aging step, for example, after adding a catalyst such as an acid catalyst to the mixture (reaction mixture) obtained by the above mixing step, it is heated to the aging temperature and held at the aging temperature for a certain period of time. After the reaction mixture is held at the aging temperature for a certain period of time, it is appropriately cooled and then neutralized, and thereafter, washing with water, drying, etc. may be performed as necessary.

[0048] Examples of the acid catalyst that can be added in the above mixing step and aging step include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, boric acid, and sulfuric acid. In addition, in the above aging step, the concentration of the acid catalyst is preferably adjusted to about 0.5% by mass or more and 5% by mass or less, and more preferably adjusted to about 1% by mass or more and 2.5% by mass or less.

[0049] The aging temperature in the above aging process may be relatively low. For example, it is preferably 40°C or higher and 60°C or lower, more preferably 35°C or higher and 60°C or lower, and even more preferably 40°C or higher and 57°C or lower. The time for maintaining at the above aging temperature (aging time) may be longer than a certain time. For example, it is preferably 75 minutes or longer and 180 minutes or shorter, more preferably 90 minutes or longer and 150 minutes or shorter, and even more preferably 100 minutes or longer and 140 minutes or shorter. When the aging temperature and the aging time are within the above ranges respectively, it is presumed that the hydroxyl groups are likely to be uniformly distributed in the polyvinyl acetal resin molecules, and thereby, it is considered that the low molecular weight components are reduced and the molecular weight distribution becomes smaller.

[0050] (Plasticizer) The interlayer film for laminated glass preferably further contains a plasticizer. That is, the above resin layer preferably further contains a plasticizer. When the interlayer film for laminated glass further contains a plasticizer in addition to the polyvinyl acetal resin, the interlayer film becomes more flexible, and the adhesiveness of the interlayer film to various adherends and the penetration resistance of the laminated glass structure obtained using the interlayer film are further improved. Further, by adjusting the type and content of the plasticizer, it becomes easier to adjust the above creep compliance per layer of the interlayer film within a predetermined range.

[0051] Examples of the plasticizer include, for example, organic ester plasticizers; organic phosphate plasticizers such as organic phosphoric acid ester plasticizers and organic phosphite plasticizers; organic ether plasticizers such as polyalkylene glycol-based plasticizers; alcohol-based plasticizers; etc. Among these, the plasticizer is preferably an organic ester plasticizer and / or an organic ether-based plasticizer.

[0052] Preferred examples of the organic ester plasticizer include monobasic organic acid esters and polybasic organic acid esters.

[0053] Examples of the monobasic organic acid ester include esters of glycol and a monobasic organic acid. The glycol is preferably a polyalkylene glycol or a monoalkylene glycol. The number of carbon atoms in each alkylene unit constituting the polyalkylene glycol and the monoalkylene glycol is preferably 2 to 4, more preferably 2 or 3. In the polyalkylene glycol, the number of repeating alkylene units is preferably 2 to 10, more preferably 2 to 4. Specific examples of the glycol include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, butylene glycol and the like. Examples of the monobasic organic acid include organic acids having 3 to 10 carbon atoms, specifically, for example, butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptanoic acid, n-octylic acid, 2-ethylhexanoic acid, n-nonanoic acid, decylic acid and the like.

[0054] Specific examples of the monobasic organic acid esters include, for example, 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 di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, triethylene glycol di-2-ethylbutyrate, ethylene glycol di-2-ethylbutyrate, 1,2-propylene glycol di-2-ethylbutyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate, 1,2-butylene glycol di-2-ethylbutyrate, and the like.

[0055] Examples of the polybasic organic acid esters include, for example, ester compounds of a dibasic organic acid having 4 to 12 carbon atoms and an alcohol having 4 to 10 carbon atoms. Examples of the dibasic organic acid having 4 to 12 carbon atoms include adipic acid, sebacic acid, azelaic acid, and the like. The alcohol having 4 to 10 carbon atoms may have a linear structure, a branched structure, or a cyclic structure.

[0056] Specific examples of the polybasic organic acid esters include, for example, dibutyl sebacate, dioctyl azelate, dihexyl adipate, dioctyl adipate, hexyl cyclohexyl adipate, diisononyl adipate, heptyl nonyl adipate, dibutyl carbitol adipate, mixed adipic acid esters, and the like. The polybasic organic acid esters may also be oil-modified sebacic acid alkyds and the like. Examples of the mixed adipic acid esters include adipic acid esters 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.

[0057] The organic ester plasticizer is not limited to the complete esters of the above-mentioned esters and may be a partial ester. The organic ester plasticizer may be, for example, 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, for example, triethylene glycol-mono-2-ethylhexanoate and the like.

[0058] The organic ester plasticizer may also be a partial ester of a trivalent or higher alcohol such as glycerin and a monobasic organic acid. The number of carbon atoms of the monobasic organic acid is preferably, for example, 3 to 24, more preferably 6 to 18. Specific examples include, for example, mono- or diesters of glycerin and stearic acid, mono- or diesters of glycerin and 2-ethylhexanoic acid, and the like.

[0059] Among the above-mentioned organic ester plasticizers, triethylene glycol-di-2-ethylhexanoate (3GO) is particularly preferably used.

[0060] Preferred examples of the organophosphorus plasticizers include organic phosphate plasticizers, organic phosphite plasticizers, and the like. Specific examples of the organophosphorus plasticizers include phosphate esters such as tributoxyethyl phosphate, isodecyl phenyl phosphate, and triisopropyl phosphate.

[0061] Preferred examples of the organic ether plasticizer include polyalkylene glycol plasticizers. Examples of polyalkylene glycol plasticizers include polyoxyalkylene compounds having a polyoxyalkylene structure, specifically, polyhydric alcohol compounds such as glycols; ester compounds of glycols with monobasic organic acids or polybasic organic acids; ether compounds of monohydric or polyhydric alcohols with polyoxyalkylene; and the like. Here, examples of glycols include polyoxyalkylene glycols and their derivatives, and examples of polyoxyalkylene include polyoxyethylene, polyoxypropylene, polyoxybutylene, random copolymers or block copolymers thereof, and the like. The polyoxyalkylene compound may be a polyhydric alcohol compound, an ester compound, an ether compound, or other compounds as described above.

[0062] Examples of polyoxyalkylene compounds include polyoxyalkylene or its derivatives. More specifically, polyoxyalkylene glycols composed of polyoxyalkylene, ether compounds of polyoxyalkylene and polyhydric alcohols, and the like are included. All of these may have hydroxyl groups at all terminals, or a part or all of the terminal hydroxyl groups may be derivatives in which a hydrogen atom is substituted with an alkyl group or an acyl group. The carbon numbers of the alkyl group and the acyl group are not particularly limited, but may be about 1 to 8, preferably 1 to 4.

[0063] Examples of polyoxyalkylene glycols include polyoxyethylene polyoxypropylene glycols such as polyethylene glycol (polyoxyethylene glycol), polypropylene glycol (polyoxypropylene glycol), poly(ethylene oxide / propylene oxide) block copolymer, poly(ethylene oxide / propylene oxide) random copolymer, and polyoxybutylene glycols such as polytetramethylene glycol.

[0064] Examples of the ether compound of polyoxyalkylene and polyhydric alcohol include ether compounds of polyhydric alcohols such as glycerol, diglycerol, trimethylolpropane, erythritol, pentaerythritol, and bisphenol A with polyoxyalkylene. Specifically, examples include polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether, polyoxyalkylene pentaerythritol ether, and the like. Further, examples of the derivative in which part or all of the hydrogen atoms of the terminal hydroxyl group are substituted with an alkyl group or an acyl group include the above-mentioned polyoxyalkylene glycols and derivatives in which part or all of the hydrogen atoms of the terminal hydroxyl group of the ether compound are substituted with an alkyl group or an acyl group. Specifically, 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, polyoxyethylene polyoxypropylene monobutyl ether, and the like.

[0065] Among the above-mentioned polyoxyalkylene compounds, compounds having a polyoxyethylene structure, a polyoxypropylene structure, or a polyoxyethylene polyoxypropylene structure are preferred. Among them, 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 in which part of the hydrogen atoms of their terminal hydroxyl groups are substituted with an alkyl group.

[0066] Preferable examples of the alcohol plasticizer include various polyhydric alcohols such as butanediol, hexanediol, trimethylolpropane, pentaerythritol, etc. Among these, trimethylolpropane is preferable.

[0067] Among the above-described 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 in which a part of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups, and 3GO is more preferable.

[0068] When the resin layer further contains a plasticizer, the content of the plasticizer (the total amount when two or more are included) is preferably 10 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin contained in the resin layer (one layer). Thereby, the intermediate film becomes moderately flexible, and the adhesiveness of the intermediate film to various adherends and the penetration resistance of the laminated glass structure are further improved. The content of the plasticizer with respect to 100 parts by mass of the thermoplastic resin is more preferably 15 parts by mass or more, further preferably 30 parts by mass or more, particularly preferably 35 parts by mass or more. The content of the plasticizer is also preferably 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Thereby, separation of the plasticizer from the intermediate film is sufficiently prevented. The content of the plasticizer with respect to 100 parts by mass of the thermoplastic resin is more preferably 70 parts by mass or less, further preferably 60 parts by mass or less, particularly preferably 50 parts by mass or less, and most preferably 45 parts by mass or less.

[0069] (Other Additives) The interlayer film for laminated glass may also appropriately contain known additives that can be used in combination with polyvinyl acetal resins or the like. That is, for example, the resin layer may contain known additives. Examples of additives other than plasticizers include ultraviolet absorbers, heat insulating agents, colorants, infrared absorbers, antioxidants, light stabilizers, adhesion adjusters, fluorescent brighteners, crystal nucleating agents, and the like. Each additive may be used alone or in combination of two or more.

[0070] (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 included in at least one of the interlayer films for laminated glass further contains an ultraviolet absorber.

[0071] The ultraviolet absorber is not particularly limited. For example, 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, compounds having an indole structure, and the like can be mentioned. Among these, from the viewpoint of excellent compatibility with thermoplastic resins and weather resistance, the ultraviolet absorber is preferably a compound having a benzotriazole structure. Examples of compounds having a benzotriazole structure include Tinuvin234, Tinuvin326, Tinuvin327, Tinuvin640, Tinuvin928 (manufactured by BASF); Eversorb88, Eversorb109 (manufactured by Everlight Chemical), etc., which are commercially available.

[0072] When the resin layer contains an ultraviolet absorber, the content of the ultraviolet absorber (the total amount when two or more are included) is 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 the materials constituting the resin layer (one layer). The content of the ultraviolet absorber 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 the materials constituting one layer of the resin layer.

[0073] Heat insulating agent When the interlayer film for laminated glass contains a heat insulating 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 insulating agent. Further, the polyvinyl acetal resin may have a layer made of a heat insulating agent (for example, a layer made of the following heat insulating particles) or a layer containing a heat insulating agent separately from or in addition to the resin layer.

[0074] The heat insulating agent is a material that can absorb infrared rays (also referred to as heat rays) of 780 nm or more. Specifically, the heat insulating agent is preferably heat insulating particles. The heat insulating 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 the 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, cesium-doped tungsten oxide particles (CWO particles); tungsten oxide particles such as thallium-doped tungsten oxide particles and rubidium-doped tungsten oxide particles; and the like. Further, heat insulating particles other than these may be used. Among these, from the viewpoint of high heat ray shielding function, the heat insulating 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 ITO particles and / or CWO particles are more preferable.

[0075] The average particle diameter of the heat shielding particles preferably has a lower limit of 10 nm or more, more preferably 20 nm or more. When the average particle diameter is within such a range, the heat ray shielding property by the heat shielding particles is further enhanced. Further, the average particle diameter of the heat shielding particles preferably has an upper limit of 100 nm or less, more preferably 80 nm or less, and still more preferably 50 nm or less. When the average particle diameter is within such a range, it becomes difficult to shield visible light by the heat shielding particles. Here, the "average particle diameter" refers to the volume average particle diameter. The average particle diameter can be measured using a particle size distribution measuring device (such as "UPA-EX150" manufactured by Nikkiso Co., Ltd.).

[0076] 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, and these are also near-infrared absorbers. The near-infrared absorber has an absorption maximum in the near-infrared region, and the absorption maximum exhibits the maximum absorption among the absorption maxima existing in the wavelength region of 380 nm to 2500 nm. Specifically, the near-infrared absorber has the maximum absorption in a wavelength region of 720 nm or more, preferably in a wavelength region of 750 nm or more and 2000 nm or less.

[0077] The heat shielding compound is preferably at least one selected from the group consisting of phthalocyanine compounds, naphthalocyanine compounds, and anthracyanine compounds. The phthalocyanine compound is phthalocyanine or a phthalocyanine derivative having a phthalocyanine skeleton, and preferably contains a metal atom therein. The naphthalocyanine compound is naphthalocyanine or a naphthalocyanine derivative having a naphthalocyanine skeleton, and preferably contains a metal atom therein. The anthracyanine compound is anthracyanine or an anthracyanine derivative having an anthracyanine skeleton, and preferably contains a metal atom therein. In the phthalocyanine compound, naphthalocyanine compound, and anthracyanine compound, the metal atom serves as the central metal of each of the naphthalocyanine skeleton, naphthalocyanine skeleton, and anthracyanine skeleton.

[0078] Among the above, the heat shielding compound is more preferably at least one selected from the group consisting of phthalocyanine compounds and naphthalocyanine compounds, and still more preferably a phthalocyanine compound. Further, as the above metal atom, a vanadium atom is preferable. Therefore, as the heat shielding compound, a phthalocyanine compound containing a vanadium atom is particularly preferable. The vanadium atom generally exists in a state where an oxygen atom is bonded (V=O). Further, 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.

[0079] When the resin layer contains a heat shielding agent, the content of the heat shielding agent (when two or more kinds are included, the total amount thereof) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.15% by mass or more in 100% by mass of the total amount of the 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 still more preferably 0.9% by mass or less in 100% by mass of the total amount of the materials constituting one layer of the resin layer.

[0080] (Colorant) When the interlayer film for laminated glass contains a colorant, the laminated glass structure obtained using the interlayer film is favorably colored in a desired color tone, enhancing the design property. For example, it is preferable that the above resin layer included in the interlayer film for laminated glass further contains a colorant. Examples of the colorant include pigments or dyes, etc., and both a pigment and a dye may be used in combination. Note that there are also colorants classified into both pigments and dyes.

[0081] Examples of the pigment 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, etc.

[0082] Examples of the dye 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 the like.

[0083] When the resin layer contains a colorant, the content of the colorant (total amount when two or more kinds are included) is preferably, for example, 0.00001% by mass or more, more preferably 0.0001% by mass or more, and still more preferably 0.001% by mass or more, based on 100% by mass of the total amount of the 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 the materials constituting the resin layer.

[0084] When the interlayer film for laminated glass contains a pigment as a colorant in particular, the content of the pigment (total amount when two or more kinds are included) is preferably, for example, 0.0001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.02% by mass or more, based on 100% by mass of the total amount of the materials constituting the resin layer (one layer). The content of the pigment 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 the materials constituting the resin layer. The pigment that can be contained in the interlayer film may be only one kind, two or more kinds, three or more kinds, ten or less kinds, or five or less kinds.

[0085] When the interlayer film for laminated glass contains a dye as a colorant in particular, the content of the dye (the total amount when two or more kinds are contained) is preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, still more preferably 0.001% by mass or more, based on 100% by mass of the total amount of the 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 the materials constituting one resin layer. Note that the dye that can be contained in the interlayer film may be only one kind, or may be two or more kinds, three or more kinds, ten or less kinds, or five or less kinds.

[0086] (Thickness) The thickness of the interlayer film for laminated glass is not particularly limited, but the layer thickness of the interlayer film (in the case of a multilayer film, it means the total thickness) is preferably 100 μm or more, more preferably 200 μm or more, still more preferably 300 μm or more. When the interlayer film for laminated glass has a thickness of a certain level or more, the remaining air and foaming during the pressure bonding with the glass plate are further sufficiently suppressed.

[0087] Also, the film thickness (total thickness) of the interlayer film for laminated glass is preferably 2000 μm or less, more preferably 1300 μm or less, still more preferably 1000 μm or less, particularly preferably 800 μm or less. When the thickness of the interlayer film for laminated glass is at a certain level or less, for example, it is possible to prevent the laminated glass structure obtained using the interlayer film from becoming thicker than necessary.

[0088] Among the total thickness of the interlayer film for laminated glass, it is preferable that the thickness of the layer satisfying the above creep compliance value occupies a certain proportion or more. Thereby, the remaining air and foaming during the pressure bonding with the glass plate are further sufficiently suppressed. For example, when the interlayer film for laminated glass is a multilayer film, when the film thickness (total thickness) of the interlayer film for laminated glass is taken as 100%, the thickness of the layer satisfying the above creep compliance value is preferably 10 to 100%, more preferably 30 to 100%, still more preferably 50 to 100%, particularly preferably 75 to 100%, and most preferably 100%.

[0089] In addition, when a laminated glass structure is formed using the above-mentioned interlayer film for laminated glass as described later, the thickness of the layer satisfying 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% or more, based on 100% of the total thickness of the laminated glass structure.

[0090] (Uneven shape) At least one surface of the interlayer film for laminated glass preferably has an uneven shape. More specifically, it is preferable that at least one surface of the interlayer film has a plurality of concave portions and a plurality of convex portions, and it is more preferable that both surfaces of the interlayer film have a plurality of concave portions and a plurality of convex portions. Further, 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.

[0091] The concave portion preferably has a groove shape with a continuous bottom. The groove shape with a continuous bottom is also referred to as a "scratched line shape". Therefore, the surface of the interlayer film for laminated glass preferably has a scratched line-shaped concave portion, and it is more preferable that both surfaces of the interlayer film have a scratched line-shaped concave portion. For example, when attempting to preliminarily bond a glass plate and an interlayer film with a rubber backing to obtain a laminated glass structure, the end portion may be temporarily bonded first, and it may be difficult for the air near the center to escape. However, when the surface of the interlayer film has a scratched line-shaped concave portion, the air near the center can also escape easily, so the adhesiveness during preliminary bonding is improved.

[0092] At least one surface of the interlayer film for laminated glass preferably has a plurality of groove-shaped recesses. In this case, it is preferable that the plurality of groove-shaped recesses are arranged in parallel. Among them, it is more preferable that the adjacent groove-shaped recesses are parallel and regularly arranged. The ease of air escape (also referred to as degassing property) when pressing the laminated film in which the interlayer film is laminated between a pair of glass plates is closely related to the connectivity and smoothness of the bottoms of the recesses on the surface of the interlayer film. By making the concavo-convex shape on at least one surface of the interlayer film into a shape in which adjacent groove-shaped recesses are parallel and regularly arranged, the connectivity of the bottoms is improved, and the degassing property is further improved.

[0093] The interval Sm between adjacent groove-shaped recesses is preferably 100 μm or more and preferably 500 μm or less. When the interval Sm of the groove-shaped recesses is within this range, more excellent degassing property is exhibited. The lower limit of the interval Sm of the groove-shaped 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 interval Sm of the groove-shaped recesses is obtained by observing the first surface and the second surface (observation range: 20 mm × 20 mm) of the interlayer film using an optical microscope (manufactured by SONIC, "BS-D8000III"), measuring the interval between adjacent recesses, and then calculating the average value of the shortest distances between the bottommost parts of adjacent recesses.

[0094] The regularly arranged groove-shaped recesses are preferably such that adjacent groove-shaped recesses are parallel and equally spaced, but the intervals between all adjacent groove-shaped recesses do not have to be equally spaced. The groove-shaped recesses do not have to be in the form of a continuous groove at the bottom, and may have a dividing wall in a part of the bottom. Also, 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.

[0095] In an intermediate film having an uneven shape on at least one surface, the surface roughness (RzJIS94) of the surface having the uneven shape is preferably 10 to 80 μm. When the surface roughness is within this range, the intermediate film can exhibit excellent degassing properties. The above surface roughness is more preferably 20 to 65 μm, and even more preferably 20 to 50 μm.

[0096] The surface roughness (RzJIS94) can be measured in accordance with JIS B0601 (1994). Here, when the concave portions of the uneven shape on the surface are in the form of engraved lines, the measurement is performed in the vertical direction so as to cross the direction in which the concave portions in the engraved line direction are continuous. For example, as a measuring instrument, "Surfcorder SE300" manufactured by Kosaka Laboratory Ltd. etc. is used, the cut-off value at the time of 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 feed rate of the stylus is 0.5 mm / second, and the stylus shape is one with a tip radius of 2 μm and a tip angle of 60°. Also, the environment at the time of measurement is 23°C and 30%RH. The intermediate film to be measured is measured after being allowed to stand for 3 hours or more under the environment at the time of measurement.

[0097] Also, in an intermediate film having an uneven shape on at least one surface, the surface roughness (Rc) of the surface having the uneven shape is preferably 10 to 40 μm. When the surface roughness is within this range, the intermediate film can exhibit excellent degassing properties. The above 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).

[0098] The intermediate film for laminated glass can be manufactured, for example, by extrusion molding or press molding etc., but it is preferably manufactured by extrusion molding. Also, as a method for forming an uneven shape on the surface of the intermediate film, for example, an embossing roll method, a calendar roll method, a profile extrusion method, a melt fracture method etc. can be mentioned. Among them, the embossing roll method is preferably adopted.

[0099] 〔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. Further, it is preferable that both the first interlayer film and the second interlayer film are the interlayer films for laminated glass of the present disclosure described above.

[0100] 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 dimming film, a display element film, or an optical film, and examples of the optical film include a polarizing film, a retardation film, an antireflection film, and a holographic film. The functional layer may also be a solar cell element as described later.

[0101] The functional film is more preferably a film provided with electronic components such as a dimming film and a display element film, and further preferably a dimming film or a display element film. That is, it is preferable that the functional layer is at least one selected from the group consisting of a dimming film and a display element film.

[0102] Generally, films with electronic components tend to have their functions deteriorated or deactivated when autoclaves under high-temperature and high-pressure conditions are applied. However, by using the interlayer film for laminated glass of the present disclosure, a laminated glass structure can be preferably manufactured even by an autoclave at low temperature. Therefore, it can be incorporated into the laminated glass structure without deactivating the functional layer. Therefore, the laminated glass structure provided with the laminated film of the present disclosure can effectively exhibit the functions derived from the functional layer. In addition, since electronic wirings, shielding printed parts, etc. are provided on the film with electronic components, complex steps (thickness differences) are likely to occur. Therefore, air remaining or foaming is likely to occur between the interlayer film and the glass plate or the functional layer during pressure bonding. However, in the present disclosure, even when pressure bonding is performed at low temperature, such generation of air remaining and foaming is sufficiently suppressed. Therefore, the obtained laminated glass structure has excellent transparency and good appearance. In addition, a laminated glass structure (for example, window glass) incorporating a dimming film or a display element film has high added value such as excellent design.

[0103] A dimming film is a film-like member provided with a dimming element. Specifically, the dimming film preferably includes two resin films and a dimming layer disposed between the two resin films. Since the surfaces of the dimming film having such a configuration that are in contact with the first interlayer film and the second interlayer film respectively are made of a resin material, the adhesiveness to these interlayer films can be improved.

[0104] The resin film used for the dimming film is not particularly limited. For example, 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. can be mentioned. Among these, from the viewpoint of handleability and the like, the resin film is preferably a polyester resin film, and more preferably a PET film. In addition, a conductive layer constituting an electrode can be provided on the surface on the dimming layer side of each of the two resin films.

[0105] The dimming layer changes the visible light transmittance by switching between applying and not applying a voltage between the conductive layers provided on each of the two resin films. Preferred examples of the dimming layer include, for example, liquid crystal layers such as polymer dispersed liquid crystal (also abbreviated as PDLC) and guest host liquid crystal (also abbreviated as GHLC); suspension particle devices (also abbreviated as SPD) layers including a resin matrix and a light adjustment suspension dispersed in the resin matrix; electrochromic material layers; electrophoretic layers comprising electrophoretic particles and a dispersant for dispersing the electrophoretic particles; and the like. Therefore, the dimming film preferably includes at least one selected from the group consisting of PDLC, GHLC, SPD, electrochromic devices, and electrophoretic film devices. That is, the above functional layer preferably includes at least one dimming film selected from the group consisting of PDLC films, GHLC films, SPD films, electrochromic films, and electrophoretic film devices.

[0106] The display element film is a film-like member provided with 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. The display element film having such a configuration can improve the adhesiveness to the first intermediate film and the second intermediate film. Note that, as the resin film used for the display element film, the resin film described above with respect to the dimming film can be appropriately selected and used. Further, an electrode-forming conductive layer may be provided on the surface on the display element side of the resin film constituting the display element film.

[0107] The film provided with electronic components is not limited to the dimming film and the display element film, and may be other functional films. In other functional films, the electronic components may be mounted on the resin film in the same manner as the dimming film and the display element film, but an aspect in which the electronic components are disposed between a pair of resin films is preferred.

[0108] 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 (also abbreviated as BIPV). The solar cell element is not particularly limited, and any solar cell element used for BIPV may be used. For example, crystalline or thin-film silicon-based solar cell elements; compound semiconductor-based solar cell elements such as CIS, CIGS, CdTe, GaAs, etc.; organic solar cell elements such as dye-sensitized, organic thin-film, perovskite, etc. may be mentioned.

[0109] The above-mentioned laminated film can be manufactured by, for example, thermocompression bonding the first intermediate film, the functional layer, and the second intermediate film. When incorporating the above-mentioned laminated film into the laminated glass structure, thermocompression bonding may be performed by first thermocompression bonding the first intermediate film, the functional layer, and the second intermediate film to form a laminated film, and then bonding the laminated film to the glass plate to form a laminated glass structure. Alternatively, before bonding, the first intermediate film, the functional layer, and the second intermediate film may be disposed between two glass plates, and when bonding the glass plate and the above-mentioned laminated film, the first intermediate film, the functional layer, and the second intermediate film may be bonded together at the same time.

[0110] Here, it is preferable to arrange the first intermediate film, the functional layer, and the second intermediate film so that the functional layer having a planar area smaller than that of each intermediate film is used and each intermediate film exists around the functional layer in a plan view (see, for example, FIGS. 2 and 3 described later). At that time, it is not necessary to arrange a gap filler on the outer periphery of the functional layer. By using the intermediate film for laminated glass of the present disclosure, a laminated glass structure can be preferably manufactured without using a gap filler.

[0111] 〔Laminated glass structure〕 The laminated glass structure of the present disclosure has a structure in which the laminated film of 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 intermediate film, a functional layer, a second intermediate film, and a second glass plate in this order. The laminated glass structure may further have one or two or more arbitrary layers between each layer, or may have two or more functional layers as described later.

[0112] (Glass plate) The laminated glass structure has a first glass plate and a second glass plate. Each glass plate may be, for example, either inorganic glass or organic glass, but is preferably inorganic glass. Note that the first glass plate and the second glass plate may be made of the same material as each other, or may be made of 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.

[0113] The inorganic glass is not particularly limited, and 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, green glass, and the like.

[0114] As the organic glass, what is generally called resin glass is used. Examples thereof include (meth)acrylic plates such as polycarbonate plates and polymethyl methacrylate plates, acrylonitrile styrene copolymer plates, acrylonitrile butadiene styrene copolymer plates, polyester plates such as polyethylene terephthalate plates, fluororesin plates, polyvinyl chloride plates, chlorinated polyvinyl chloride plates, polypropylene plates, polystyrene plates, polysulfone plates, epoxy resin plates, phenolic resin plates, unsaturated polyester resin plates, polyimide resin plates, and other various organic glass plates. The resin plate may be appropriately subjected to surface treatment or the like.

[0115] The thickness of each glass plate is not particularly limited, but for example, it is preferably about 0.1 to 15 mm, and more preferably 0.5 to 5 mm. The thickness of each glass plate may be the same or different between the first glass plate and the second glass plate.

[0116] 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 glass plate and the second glass plate. In this case, various functions are imparted to the glass plate. Other members are preferably members constituting, for example, electronic devices or optical members, and more preferably members constituting a display device. Examples of the display device include a liquid crystal display device, an organic EL display device, an LED display device, and a segment display device. Among them, a liquid crystal display device is preferable. The display device is, for example, a display panel in which a display layer such as a liquid crystal layer or an organic EL layer, a light-emitting element, etc. are provided on a glass plate as a substrate. However, the glass plate as the substrate may be used as the first glass plate and / or the second glass plate. Each glass plate may also have various functional layers laminated thereon, such as a functional film; a conductive layer constituting an electrode, a sensor, etc.; an antireflection layer; a hard coat layer; etc.

[0117] (Layer structure) The laminated glass structure includes a pair of intermediate films (i.e., the first intermediate film and the second intermediate film) that sandwich a functional layer between a pair of glass plates (i.e., the first glass plate and the second glass plate). For example, the first intermediate film is preferably adhered to the first glass plate and the functional layer to join them, and the second intermediate film is preferably adhered to the second glass plate and the functional layer to join them. Thereby, the pair of glass plates, the pair of intermediate films, and the functional layer are integrated. The layer structure in such a mode is represented by G1 / F1 / Z / F2 / G2 (see FIG. 1). G1 represents the first glass plate, G2 represents the second glass plate, F1 represents the first intermediate film, F2 represents the second intermediate film, and Z represents the functional layer, respectively. FIG. 1 is a schematic diagram showing an example of the layer structure of the laminated glass structure.

[0118] In the above description, an embodiment in which two intermediate films and one functional layer are provided between a pair of glass plates has been exemplified. However, three or more intermediate films and two or more functional layers may be provided between the pair of glass plates. In this case, it is preferable that the intermediate films and the functional layers are alternately arranged, and it is preferable that intermediate films are arranged at the positions closest to each glass plate. For example, when three or more intermediate films and two or more functional layers are provided between a pair of glass plates, the layer structure of the laminated glass structure is preferably G1 / F3 / Z1 / F4 / Z2 / F5 / G2. Z1 and Z2 represent functional layers, which may be the same or different. F3, F4, and F5 represent intermediate films, which may be the same or different. At least one of F3, F4, and F5 is the intermediate film for laminated glass of the present disclosure.

[0119] 〔Method for manufacturing a laminated glass structure〕 The laminated glass structure of the present disclosure is preferably manufactured by a method in which the above laminated film is disposed between a pair of glass plates and these are bonded by pressing them together to obtain the laminated glass structure. As described above, when the first intermediate film is used, even without using a gap filler, delamination of the layer interface, residual air, and foaming can be sufficiently suppressed. Therefore, in the above manufacturing method, the glass plate and the laminated film may be pressed together without disposing a gap filler on the outer periphery of the functional layer. In this case, the above manufacturing method can omit the operation of disposing a gap filler, so that the manufacturing process is simplified. Moreover, for example, a decrease in yield due to shrinkage of the gap filler can be sufficiently suppressed, and the cost for the material using the gap filler is also unnecessary, which is extremely useful industrially. Further, by not using a gap filler, the film thickness at the end of the laminated glass structure can be reduced, so that intrusion of moisture into the laminated glass structure is sufficiently suppressed and the effects derived from the functional layer are effectively exhibited.

[0120] In the above manufacturing method, first, a first glass plate, a second glass plate, and the above laminated film disposed between these glass plates or each member (each intermediate film and functional layer) constituting the above laminated film are prepared.

[0121] 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 be attached to the glass plate before being integrated into the laminated glass structure. Therefore, as at least one of the first glass plate and the second glass plate used in the above manufacturing method, a glass plate to which a functional member is attached may be prepared. 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.

[0122] In the above manufacturing method, it is then preferable to dispose the laminated film between the first glass plate and the second glass plate and bond them together to form an integrated laminated glass structure. Also, it is preferable to dispose each member (i.e., each intermediate film and functional layer) constituting the laminated film between the first glass plate and the second glass plate and bond them together to form an integrated laminated glass structure in which the laminated film is incorporated. Here, each member constituting the laminated film may be disposed according to the layer structure of the resulting laminated glass structure. For example, they may be disposed between the first glass plate and the second glass plate in the order of the first intermediate film, the functional layer, and the second intermediate film.

[0123] The above bonding (also referred to as pre-bonding or main bonding) may be performed in a two-step process of performing main bonding after pre-bonding, or may be performed in one step, but it is preferable to perform it in two steps. The pre-bonding may be performed by a vacuum bag, a ring bag, a nipper roll, or other pressing machines. The main bonding is preferably performed in an autoclave, but may also be performed by other pressing machines. When bonding in one step, it is preferable to bond with a vacuum bag or a ring bag, but it may also be performed by other pressing machines.

[0124] In the above manufacturing method, the lamination may be performed under low-temperature conditions according to the heat resistance of the functional layer. Since the interlayer film for laminated glass of the present disclosure has excellent fluidity, even if a laminated glass structure is manufactured by laminating under low temperature or low pressure, the obtained laminated glass structure can exhibit high safety. Note that by performing the lamination under low-temperature conditions or low-pressure conditions, deterioration or deactivation of the functional layer can be sufficiently prevented. Also, even when a functional member or the like is attached to the glass plate, deterioration or deactivation of the member can be sufficiently prevented.

[0125] From the viewpoint of more reliably preventing deterioration or deactivation of the functional layer or the like, the temperature during the lamination is preferably 110°C or lower, more preferably 100°C or lower. Also, from the viewpoint of further preventing the generation and foaming of residual air, the temperature during the lamination is preferably 60°C or higher, more preferably 70°C or higher.

[0126] Similarly, from the viewpoint of more reliably preventing deterioration or deactivation of the functional layer or the like, the pressure during the lamination is preferably 1.2 MPa or lower, more preferably 0.8 MPa or lower. The lower limit value of the pressure during the lamination is not particularly limited. For example, when performing the lamination under pressure such as in an autoclave, it is preferably 0.05 MPa or higher, more preferably 0.1 MPa or higher.

[0127] The time for performing the lamination at the above temperature and / or pressure is not particularly limited, but for example, 1 to 120 minutes is preferable, and 5 to 60 minutes is more preferable.

[0128] In the above manufacturing method, as described above, it is preferable to perform preliminary adhesion (also referred to as preliminary lamination or temporary pressure bonding) before the above lamination. Thereby, it is possible to sufficiently suppress a decrease in transmittance and a decrease in adhesive strength that may occur in the autoclave process under low-temperature conditions.

[0129] Depending on the type of the functional layer or the like, from the viewpoint of further preventing deterioration or deactivation, the preliminary adhesion may be performed under low-temperature conditions, or the preliminary adhesion may be performed under low-temperature and low-pressure conditions. In that case, for example, the temperature during the preliminary adhesion is preferably 110°C or lower, more preferably 100°C or lower. Also, from the viewpoint of further preventing the generation and foaming of residual air, the temperature during the preliminary adhesion is preferably 60°C or higher, more preferably 70°C or higher. The pressure during the preliminary adhesion is preferably 0.6 MPa or lower. Further, when performing the preliminary adhesion under a negative pressure such as when using a vacuum back, the pressure during the preliminary adhesion is preferably 0.3 MPa or lower, more preferably 0.095 MPa or lower, and still more preferably 0.09 MPa or lower. When performing the preliminary adhesion under pressure, the pressure is also preferably 0.01 MPa or higher, more preferably 0.05 MPa or higher.

[0130] The time for performing the preliminary adhesion at the above temperature and / or pressure is not particularly limited, but for example, 0 to 60 minutes is preferable, and 0 to 30 minutes is more preferable.

[0131] (Use) The laminated glass structure of the present disclosure can be used in various applications. For example, the laminated glass structure of the present disclosure can be used for vehicles such as automobiles and trains, various vehicles such as ships and airplanes, various buildings such as buildings, condominiums, single-family houses, halls, and stadiums, machine tools such as cutting and grinding machines, and construction machines such as excavators and cranes, as window glass, and for partitions inside various vehicles and various buildings. Among them, the laminated glass structure is preferably used for vehicle applications such as automobiles and trains or building applications. Thus, both the laminated glass for vehicles and the laminated glass for buildings composed of the laminated glass structure of the present disclosure are those found by the present inventors. The laminated glass structure is particularly preferably used for window glass for vehicles or BIPV, and particularly preferably used for window glass for vehicles. The window glass for vehicles is preferably the front glass, side glass, rear glass, or roof glass of an automobile or a train.

[0132] 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 a display. Further, the laminated glass structure of the present disclosure can also be used as a cover glass for various displays. For example, the laminated glass structure may be applied to in-vehicle displays and the like.

Examples

[0133] The present disclosure will be described in more detail by way of examples and the like, but the present disclosure is not limited by these examples in any way. Unless otherwise specified, "parts" represents "parts by mass" and "%" represents "% by mass". The weight average molecular weight of the resin and the creep compliance at 90 °C per layer of the film were determined according to the methods described above, respectively.

[0134] <Materials, etc.> Each material or member used in the preparation examples and the like is as follows. (1) Glass plate Glass plate: manufactured by Misawa Glass Co., Ltd., trade name "float plate glass", size 30 cm × 30 cm × 3 mm

[0135] (2) PET substrate Manufactured by Toray Industries, Inc., trade name "Lumirror (registered trademark) T60", film thickness 188 μm

[0136] (3) Thermoplastic resin Preparation Example A1 (Resin 1) Into a reactor equipped with a stirring device, 1800 ml of ion-exchanged water, 150 g of polyvinyl alcohol A (average degree of polymerization 1700, saponification degree 99 mol%), and 50 g of polyvinyl alcohol B (average degree of polymerization 800, saponification degree 99 mol%) were added, and the mixture was heated and dissolved with stirring to obtain a polyvinyl alcohol solution. Next, this solution was cooled, and after adjusting the temperature to 40 °C, 30% hydrochloric acid was added as a catalyst so that the hydrochloric acid concentration became 0.9% by mass. After adjusting the temperature to 20 °C, n-butylaldehyde was added with stirring so that the amount became 15 mol%. Thereafter, the solution was adjusted to 13 °C, and when n-butylaldehyde was added so that the amount became 54.7 mol%, white particulate polyvinyl butyral resin was precipitated. 20 minutes after the second addition of n-butylaldehyde, 30% hydrochloric acid was added so that the hydrochloric acid concentration became 1.1% by mass, and then the temperature was raised to 48 °C and aged at a ripening temperature of 48 °C 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 amount 30.9 mol%, acetalization degree 68.1 mol%, acetylation degree 0.99 mol%, weight average molecular weight 245000).

[0137] Preparation Example A2 (Resin 2) Into a reactor equipped with a stirring device, 1800 ml of ion-exchanged water and 200 g of polyvinyl alcohol A (average degree of polymerization 1700, saponification degree 99 mol%) were added, and the mixture was heated and dissolved with stirring to obtain a polyvinyl alcohol solution. Next, 30% hydrochloric acid was added as a catalyst so that the hydrochloric acid concentration became 0.2% by mass, and after adjusting the temperature to 15 °C, n-butylaldehyde was added with stirring so that the amount became 10 mol%. Thereafter, when n-butylaldehyde was added so that the amount became 60 mol%, white particulate polyvinyl butyral resin was precipitated. 10 minutes after the precipitation, 30% hydrochloric acid was added so that the hydrochloric acid concentration became 1.8% by mass, and then the temperature was raised to 53 °C and aged at a ripening temperature of 53 °C 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).

[0138] Preparation Example A3 (Resin 3) Instead of aging Resin 2 at an aging temperature of 53°C for 2 hours, it was aged at an aging temperature of 63°C for 2 hours. Otherwise, in the same manner as in Preparation Example A2 (Resin 2), 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.

[0139] (4) Plasticizer 3GO: Triethylene glycol-bis-(2-ethylhexanoate), manufactured by Sekisui Chemical Co., Ltd., molecular weight 402

[0140] (5) Intermediate film Preparation Example B1 (Film 1) To 100 parts of Resin 1, 40 parts of plasticizer (3GO) was mixed to obtain a resin composition. The obtained resin composition was fed into a twin-screw extruder, and embossing was imparted using an embossing roll to produce Film 1 with a film thickness of 760 μm. For the obtained Film 1, the creep compliance J(t) at 90°C per layer was measured. The results are shown in Table 1.

[0141] Preparation Example B2 (Film 2) A film-like Film 2 with a thickness of 760 μm was produced in the same manner as in Preparation Example B1, except that Resin 2 was used instead of Resin 1. For the obtained Film 2, the creep compliance J(t) at 90°C was measured. The results are shown in Table 1.

[0142] Preparation Example B3 (Film 3) A film-like Film 3 with a thickness of 760 μm was produced in the same manner as in Preparation Example B1, except that Resin 3 was used instead of Resin 1. For the obtained Film 3, the creep compliance J(t) at 90°C was measured. The results are shown in Table 1.

[0143] Preparation Example B4 (Film 4) The film 4 with a thickness of 760 μm in film form was produced in the same manner as in the case of film 1 except for the temperature and pressure conditions during embossing. For the obtained film 4, the creep compliance J(t) at 90°C per layer was measured. The results are shown in Table 1.

[0144] Preparation Example B5 (Film 5) The film 5 with a thickness of 760 μm in film form was produced in the same manner as in the case of film 1 except for the temperature and pressure conditions during embossing. For the obtained film 5, the creep compliance J(t) at 90°C per layer was measured. The results are shown in Table 1.

[0145] <Evaluation Test> For each film obtained in the preparation examples, the remaining embossing distance and surface roughness (RzJIS94 and Rc) were determined according to the method described above. Figure 4 is a photograph taken from above of the laminate when measuring the remaining embossing distance of film 1. T indicates the location where the transmittance was measured, and the transmittance was measured by sliding the transmittance measuring device in the T1 direction. The results are shown in Table 1.

[0146]

Table 1

[0147] (6) Laminated glass structure Test Example 1 Two glass plates, two films 1, and two PET substrates were prepared. One film 1, two PET substrates, and the other film 1 were stacked in this order on one glass plate, and then the other glass plate was stacked on top of them to obtain laminate 1. As shown in FIGS. 2 and 3, the glass plate and film 1 each had a planar size of 300 mm × 300 mm, and the two PET substrates each had a planar size of 200 mm × 200 mm. These were arranged so that the centers of the glass plate, film 1, and PET substrate overlapped in plan view. FIG. 2 is a schematic view of the layer structure of laminate 1 viewed from the side, and FIG. 3 is a plan schematic view of laminate 1. Here, in FIGS. 2 and 3, the functional layer Z is read as two PET substrates.

[0148] The above laminate 1 was placed in a vacuum laminator "LAMINATOR 0505S" manufactured by Nisshinbo Mechatronics Co., Ltd., and degassed at 90 °C and a vacuum degree of 4 kPa for 5 minutes. Then, while maintaining the degassing at 90 °C, a pressure of 100 kPa was applied to laminate 1 at a medium speed press (pressure increase rate: 2 kPa / s), and then it was held at 90 °C and 100 kPa for 3 minutes. Thereafter, under the conditions of 140 °C and 1.3 MPa, pressure bonding was performed using an autoclave for 20 minutes to obtain a laminated glass structure 1.

[0149] Test Example 2 A laminated glass structure 3 was obtained in the same manner as in Test Example 1, except that film 4 was used instead of film 1 disposed on both sides of the two PET substrates.

[0150] Test Example 3 A laminated glass structure 4 was obtained in the same manner as in Test Example 1, except that film 5 was used instead of film 1 disposed on both sides of the two PET substrates.

[0151] Comparative Test Example 1 A laminated glass structure C1 was obtained in the same manner as in Test Example 1, except that film 3 was used instead of film 1 disposed on both sides of the two PET substrates.

[0152] Comparative Test Example 2 A laminated glass structure 2 was obtained in the same manner as in Test Example 1, except that film 2 was used on both sides instead of film 1 disposed on both sides of the two PET substrates.

[0153] <Evaluation Test> Using each of the laminated glass structures obtained in the test examples and the like, the following evaluation tests were conducted. The results are shown in Table 2. Table 2 also shows the thicknesses of the interlayer film and the PET substrate constituting each laminated glass structure (the glass plates are omitted).

[0154] (Step Followability) Each of the laminated glass structures obtained in the test examples and the like was prepared (see also FIGS. 2 and 3). Assuming that the refractive index of each layer is 1.5, using a multilayer film thickness measuring instrument "OptiGauge" manufactured by Lumetrics, Inc., USA, the thickness (a) of the region without the PET substrate in the laminated glass structure and the thickness (b) at the center of the region with the PET substrate in the laminated glass structure were measured. When it is difficult to perform the measurement using an optical method, the laminated glass structure may be appropriately cut out and each thickness may be measured using a caliper or the like. Then, the ratio (a / b) of the thickness (a) to the thickness (b) was calculated and evaluated according to the following criteria. ◎(Excellent): The above value is 0.9 or more and 1.0 or less. 〇(Good): The above value is 0.8 or more and less than 0.9. ×(Bad): The above value is less than 0.8, or cracks occur and measurement cannot be performed.

[0155] Here, the "thickness (b) at the center of the region with the PET substrate in the laminated glass structure" is the sum of the thicknesses of each layer at the site corresponding to the centroid of the PET substrate when the laminated glass structure is viewed in plan. Further, the "thickness (a) of the region without the PET substrate in the laminated glass structure" is the sum of the thicknesses of each layer at the midpoint between an arbitrary end E1 of the PET substrate and an end E2 of the laminated glass structure at the position closest along the horizontal direction from the end E when the laminated glass structure is viewed in plan.

[0156]

Table 2

Explanation of Symbols

[0157] 10: Laminated glass structure 10A: Laminate used when calculating the remaining embossing distance G1, G2, G: Glass plates F1, F2, F: Interlayer films Z: Functional layer (or PET substrate)

Claims

1. It contains a polyvinyl acetal resin and a plasticizer, at least one surface has an uneven shape, and the emboss remaining distance calculated by the following method is less than 27 mm, The creep compliance at 90 °C per layer is 8.0×10−5 Pa−1 or more and 1.0×10−3 Pa−1 or less, The amount of hydroxyl groups in the polyvinyl acetal resin is 30.9 mol% or more, 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 in which a part of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups An interlayer film for laminated glass, characterized by the above. <Method for calculating the emboss remaining distance> Prepare two float glass plates with a length of 300 mm, a width of 300 mm, and a thickness of 3 mm and conforming to JIS R3202 (2011). Further, prepare two interlayer films for laminated glass with a length of 300 mm, a width of 300 mm, and a thickness of 760 μm, and one polyethylene terephthalate (PET) film with a length of 200 mm, a width of 200 mm, and a thickness of 188 μm. After that, stack the float glass plates, the interlayer films for laminated glass, the PET film, the interlayer films for laminated glass, and the float glass plates in this order and so that the centers of the members coincide in plan view. The obtained laminate (referred to as laminate 1) is degassed at a vacuum degree of 4 kPa for 5 minutes. When measuring the transmittance (referred to as transmittance B) from one end of the laminate 1 toward the end opposite to the one end along the center line passing through the center of the PET film when the laminate 1 after degassing is viewed in plan view, measure the distance between the first part where the ratio (B / A) of the following transmittance A and the transmittance B first becomes 0.75 or less and the end close to the first part in the region where the PET film is arranged, and set this distance as the emboss remaining distance. The transmittance A is the maximum value of the transmittance of the following laminate 3. After preparing two sheets each of the same float plate glass and the interlayer film for laminated glass used when obtaining the laminate 1, the float plate glass, the interlayer film for laminated glass, the interlayer film for laminated glass, and the float plate glass are laminated in this order and with the centroids of the respective members coinciding in plan view. This laminate (referred to as laminate 2) is placed in a vacuum laminator "LAMINATOR 0505S" manufactured by Nisshinbo Mechatronics Inc., and degassed for 5 minutes at a vacuum degree of 4 kPa. Next, while still degassed, a pressure is applied to the laminate 2 up to 100 kPa at a medium speed press (pressure increase rate: 2 kPa / s), and then held at 100 kPa for 3 minutes. Thereafter, a laminate 3 is obtained by performing pressure bonding for 20 minutes using an autoclave under the conditions of 140 °C and 1.3 MPa.

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, characterized in that.

3. Comprising a polyvinyl acetal resin and a plasticizer, at least one surface having an uneven shape, and the emboss remaining distance calculated by the following method being less than 27 mm, The creep compliance at 90 °C per layer is 8.0×10−5 Pa−1 or more and 1.0×10−3 Pa−1 or less, The polyvinyl acetal resin has a weight average molecular weight of 245,000 or more and 280,000 or less, 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 in which a part of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups The interlayer film for laminated glass, characterized in that. <Method for calculating the emboss remaining distance> Two float plate glasses with dimensions of 300 mm in length × 300 mm in width × 3 mm in thickness and conforming to JIS R3202 (2011) were prepared. Further, two interlayer films for laminated glass with dimensions of 300 mm in length × 300 mm in width × 760 μm in thickness and one polyethylene terephthalate (PET) film with dimensions of 200 mm in length × 200 mm in width × 188 μm in thickness were prepared. After that, the float plate glass, the interlayer film for laminated glass, the PET film, the interlayer film for laminated glass, and the float plate glass were laminated in this order and with the centroid of each member coinciding in plan view. The obtained laminate (referred to as laminate 1) was degassed at a vacuum degree of 4 kPa for 5 minutes. When measuring the transmittance (referred to as transmittance B) along the center line passing through the centroid of the PET film when viewing the degassed laminate 1 in plan view from one end of the laminate 1 toward the end opposite to that end, the distance between the first site where the ratio (B / A) of the following transmittance A and the transmittance B first becomes 0.75 or less and the end of the region where the PET film is disposed that is close to the first site is measured, and this distance is defined as the embossing remaining distance. The transmittance A is the maximum value of the transmittance of the following laminate 3. Two of each of the same float plate glass and the interlayer film for laminated glass used when obtaining the laminate 1 were prepared. Then, the float plate glass, the interlayer film for laminated glass, the interlayer film for laminated glass, and the float plate glass were laminated in this order and with the centroid of each member coinciding in plan view. This laminate (referred to as laminate 2) was placed in a vacuum laminator "LAMINATOR 0505S" manufactured by Nisshinbo Mechatronics Inc. and degassed at a vacuum degree of 4 kPa for 5 minutes. Next, while still degassed, a pressure of up to 100 kPa was applied to the laminate 2 at a medium speed press (pressure increase rate: 2 kPa / s) and then held at 100 kPa for 3 minutes. Thereafter, lamination was performed for 20 minutes using an autoclave under the conditions of 140°C and 1.3 MPa to obtain laminate 3.

4. At least one surface has an uneven shape, The surface roughness (RzJIS94) measured in accordance with JIS B0601 (1994) of the surface having the uneven shape is 10 to 80 μm, The surface roughness (Rc) measured in accordance with JIS B0601 (2013) of the surface having the uneven shape is 10 to 40 μm The interlayer film for laminated glass according to claim 1, characterized in that.

5. At least one surface has an uneven shape, and the surface roughness (RzJIS94) measured in accordance with JIS B0601 (1994) of the surface having the uneven shape is 10 to 80 μm, and the surface roughness (Rc) measured in accordance with JIS B0601 (2013) of the surface having the uneven shape is 10 to 40 μm. The interlayer film for laminated glass according to claim 3, characterized in that.

6. The laminated film has a structure in which the interlayer film for laminated glass according to any one of claims 1 to 5 and a functional layer are laminated. The laminated film is characterized by that.

7. It 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 the interlayer film for laminated glass according to any one of claims 1 to 4. The laminated film according to claim 6, characterized in that.

8. The functional layer is at least one selected from the group consisting of a dimming film and a display element film. The laminated film according to claim 6, characterized in that.

9. The functional layer is a dimming film, and the dimming film includes at least one selected from the group consisting of polymer dispersed liquid crystal (PDLC), guest host liquid crystal (GHLC), suspended particle device (SPD), electrochromic device, and electrophoretic film device. The laminated film according to claim 6, characterized in that.

10. The laminated glass structure has a structure in which the laminated film according to claim 6 is sandwiched between a pair of glass plates. The laminated glass structure is characterized by that.

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